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Medical Patent Abstract
A system for disposing of medical waste is generally configured
to sort waste items into a plurality of disposable containers according
to applicable rules and regulations governing the handling and/or
disposal of such items. In some embodiments, a system comprises
sorting stations, each of which houses a number of disposable containers.
Each station can identify an item of waste, determine the most appropriate
container for the item, and facilitate disposal of the item in the
appropriate container.
Medical Patent Claims
What is claimed is:
1. A system comprising: a plurality of container compartments,
each container compartment configured to receive a removable container;
a plurality of removable containers, wherein each of said removable
containers comprises an opening; a movable lid coupled with each
of said removable containers; wherein the removable containers are
configured to be placed within the container compartments, wherein
each of the removable containers is associated with at least one
of a plurality of medical waste categories, wherein the movable
lid is movable to an open position; and wherein the movable lid
is movable to a closed locked position; a manual input device configured
to receive information on a medical waste item; a control system
configured to classify said waste item based on the information
received from the manual input device; wherein the control system
is further configured to assign the medical waste item to at least
one medical waste category; and wherein the control system is further
configured to identify one of the removable containers based on
the medical waste category; wherein the control system is further
configured to allow the movable lid coupled to the identified removable
container to move to the open position; and wherein the control
system is further configured to lock the movable lid in a closed
position.
2. The system of claim 1, wherein at least one of said containers
comprises a translucent portion.
3. The system of claim 1, wherein said moveable lid is coupled
to said removable container via a hinging mechanism.
4. The system of claim 1, wherein said moveable lid is coupled
to said removable container via a sliding mechanism.
5. The system of claim 1, wherein at least one of said containers
is disposable or reusable.
6. The system of claim 1, wherein the manual input device comprises
a touch screen.
7. The system of claim 1, wherein the manual input device comprises
a keyboard.
8. The system of claim 1, further comprising a barcode scanner
that reads a barcode located on said medical waste item.
9. The system of claim 1, wherein at least one of said containers
comprises a viewing window configured to allow a user to visually
determine a contents of the container.
10. The system of claim 1, further comprising a sensor configured
to detect the level of waste within at least one of said containers.
11. The system of claim 1, further comprising a machine-readable
key located on at least one of the removable containers, wherein
said key is configured to indicate the container's waste category
type to the system.
12. The system of claim 11, wherein the machine-readable key is
optically readable.
13. The system of claim 11, wherein the machine-readable key is
alphanumeric.
14. The system of claim 11, wherein the machine-readable key is
graphical.
15. The system of claim 11, wherein the machine-readable key comprises
a color.
16. The system of claim 11, wherein the machine-readable key is
magnetically readable.
17. The system of claim 11, wherein the machine-readable key comprises
at least one microchip.
18. The system of claim 11, wherein the machine-readable key comprises
a physical feature associated with the container.
19. The system of claim 18, wherein the physical feature is molded
into the container.
Medical Patent Description
BACKGROUND
1. Field of the Invention
The invention relates in general to the field of waste disposal
systems, and in particular to a system for sorting medical waste
for disposal.
2. Description of the Related Art
The Environmental Protection Agency (EPA) enforces the Resource
Conservation & Recovery Act (RCRA) which was enacted in 1976
in order to control the disposal of harmful or hazardous waste materials.
There are currently over 100,000 drugs commercially available in
the United States, of which about 14,000 are considered hazardous
by RCRA requirements. A typical medium size hospital utilizes thousands
of different drugs in a year of which hundreds are considered hazardous.
The EPA is increasingly enforcing hospitals' compliance with the
RCRA requirements because it has been shown in several studies that
the 72 million pounds of pharmaceutical waste generated each year
by hospitals is contributing to the pollution of groundwater and
endocrine system damage in humans and other species. In addition,
many organizations including Hospital for a Healthy Environment
(H2E) and Joint Council for Accreditation of Healthcare Organizations
(JCAHO) are pressing hospitals to be more environmentally friendly.
In view of these changes, hospitals are increasing efforts to audit
their own compliance with the laws. As a result, these hospitals
are becoming more aware of the difficulty of sorting the numerous
pharmaceutical waste streams that the EPA, Department of Transportation
(DOT), Drug Enforcement Administration (DEA), and some states require.
More than 3.2 million tons of medical waste is generated by hospitals,
medical clinics and pharmaceutical manufacturers each year. Half
of this waste is considered infectious. Most of the infectious waste
was treated in over 2400 incinerators throughout the country, until
1998 when the EPA began to enforce tough environmental emission
laws that have reduced the number of incinerators to just over a
hundred nationwide. Now much of the infectious waste is hauled to
these remaining incinerators, often a substantial distance, or is
treated by alternative technologies such as autoclaves and chemical
processors. There is very little choice for hospitals because of
the upfront cost and large footprint of the processing equipment.
Although many companies have offered different kinds of equipment,
the prices vary from a few hundred thousand dollars for smaller
units to a few million for large units. Because of the long cycling
times to decontaminate the waste, the equipment typically is very
large in order to provide acceptable throughput. There are also
several companies that provide a service to hospitals by utilizing
chemical processors mounted on trucks. They go to a facility and
decontaminate the infectious waste, allowing the treated waste to
be hauled to a local landfill. There are concerns that this technology
may not completely treat the waste in all circumstances and the
chemical residue left after processing may remain an ecological
issue.
Increasingly, hospitals are required to comply with the recent
and projected enforcement of federal and state hazardous pharmaceutical
waste regulations. Currently, clinicians must manually sort pharmaceutical
waste streams into different colored containers for proper disposal
of the separate waste streams. It is often not clear to a clinician
which pharmaceuticals or waste materials are hazardous simply by
looking at the container. Such confusion may lead to clinicians
throwing hazardous drugs in non-hazardous containers such as sharps
containers, infectious waste bags, non-hazardous pharmaceutical
containers or simply down the drain.
SUMMARY OF THE INVENTION
There remains a need for a system for allowing clinicians to more
easily sort medical waste items for appropriate disposal. There
also remains a need for an automated system of waste disposal that
encourages and facilitates hospital compliance with the relevant
federal and state regulations.
Several embodiments of the present application describe systems
and devices to sort and process infectious and pharmaceutical waste
streams. Embodiments of a medical waste sorting system advantageously
provide a labor savings for doctors, nurses and other clinicians
by taking the bulk of the decision making associated with sorting
medical waste away from the clinician. In one embodiment, a medical
waste sorting system is provided, which will help clinicians conveniently
comply with the recent and projected enforcement of federal and
state hazardous waste laws. In some embodiments, the system can
be configured to scan a bar code, RFID tag, or other system for
identifying a spent drug. The spent drug can then be classified
into an appropriate waste category, and a door can be automatically
opened to provide access to a unique waste container for convenient
disposal of the drug in compliance with applicable regulations.
According to another embodiment, a system is provided which will
render infectious hospital or laboratory waste non-infectious. This
embodiment will provide an economical service to a hospital by utilizing
a self-contained truck-mounted version. Alternatively, a stand alone
version can be made available for hospital purchase.
In another embodiment, a system for treating hazardous medical
waste items in order to render them non-hazardous is provided.
In addition to the need for medical and pharmaceutical waste sorting,
there exists a need to improve areas of water quality analysis and
workplace safety. These areas include sampling water quality throughout
the hospital to pinpoint inappropriate dumping of hazardous materials
down the drain and improved programs that reduce hospital worker
exposure to hazardous materials in the workplace.
In one embodiment, a system for sorting waste is provided. The
system of this embodiment comprises a plurality of containers associated
with a plurality of waste categories. A waste item identification
device is configured to determine a qualitative parameter of an
item of medical waste. A database is provided with medical waste
item classification information. A control system is programmed
to compare the qualitative parameter of the waste item to information
contained in the database in order to assign the item to a medical
waste category. The system also includes a sorting mechanism configured
to place the item into one of the containers based on the medical
waste category.
In another embodiment, a system for sorting waste comprises a waste
item identification means for identifying a qualitative parameter
of an item of medical waste, and a database means for classifying
medical waste items into categories according to rules and regulations
affecting the disposal of medical waste items. The system also includes
control means for comparing the qualitative parameter of the waste
item to information contained in the database, and for assigning
the item to a unique medical waste category. A sorting means is
also provided for placing the item into a container associated with
the waste category.
In another embodiment, a system for determining the level of contents
within a waste container is provided. The system of this embodiment
comprises a plurality of containers, each one being associated with
at least one of a plurality of a waste categories. Waste is placed
in the containers based on a determination by a database that comprises
medical waste classification information. At least one optical source
is positioned on one side of at least one of the containers, and
at least one optical detector is positioned on an opposite side
of at least one of the containers. A processor is configured to
determine a level of contents of a container by analysis of the
data received from the optical detector.
Another embodiment of a system for determining the level of contents
within a container comprises a means for containing waste items
comprising a plurality of containers, and a means for producing
an optical signal on one side of at least one of the plurality of
containers. A means for receiving an optical signal is positioned
on an opposite side of at least one of the containers, and means
for processing signals from the respective means for producing and
means for receiving is configured to determine a level of contents
within at least one of the containers.
In another embodiment, a system comprises a container for storing
sorted waste and a sensor configured to measure a presence of waste
within the container without physically contacting the container.
In another embodiment, a system comprises a means for storing sorted
waste and a means for determining a quantity of waste within the
container.
In another embodiment, a disposable container for use in a medical
waste system comprises a plurality of walls defining an internal
space and an opening configured to provide access to the internal
space. An automatically operable door is configured to selectively
occlude and reveal the opening, and the door is configured to be
operated by a machine in which the container is placed. A machine-readable
identification key is provided on at least a portion of the container.
The machine-readable identification key bears a container type which
defines a category of waste to be placed in the container.
In another embodiment, a disposable container for use in a medical
waste system comprises a plurality of walls defining an internal
space and an opening configured to provide access to the internal
space. A flange extends from a portion of the container and comprises
a pattern of holes configured to indicate a container type. The
container type defines at least one category of waste to be placed
in the container.
In another embodiment, a system comprises a plurality of disposable
containers of different types. Each container type corresponds to
a category of medical waste, and each container comprises a machine-readable
key configured to indicate the container's type to a sorting machine.
Each container also comprises an automatically-operable gate configured
to selectively occlude and reveal an opening of the container. The
gate is further configured to be automatically locked.
In another embodiment, a container for use in a medical waste system
comprises a means for defining an internal space, and an aperture
means for providing access to the internal space. An openable means
for selectively occluding and revealing the aperture means is operable
by an automated machine. A key means is also provided for indicating
a container type to the machine.
In another embodiment, a disposable container for use in a medical
waste system comprises a means for defining an internal space and
a means for provide access to the internal space. A flange means
extends from a portion of the container and indicates a category
of waste to be placed in the container.
In another embodiment, a method of using a disposable container
comprises receiving a disposable container in a sorting machine.
The method is continued by reading an identification key on the
container. The identification key defines a category of waste to
be placed in the container. The method is continued by directing
a user to place a plurality of waste items in the container and
alerting a user when the container is full.
In another embodiment, a method of using a disposable container
comprises receiving a plurality of disposable containers in a sorting
machine, wherein each container corresponds to a waste category.
The method further comprises reading an identification key on each
container. The identification key defines a category of waste to
be placed in the container. The method further comprises determining
a waste category to which an item of waste belongs, providing access
to a selected one of the containers, and directing a user to place
the waste item in the selected container.
In another embodiment, a method of using a disposable container
for sorting and disposing of medical waste comprises placing a plurality
of containers in a sorting machine. Each container comprising an
opening configured to provide access to an internal space. The method
further comprises operating the machine to read an identification
key from each container to determine a category of waste to be placed
in each container and to automatically operate a door to selectively
occlude and reveal the opening.
In another embodiment, a method of sorting medical waste comprises,
in no particular order, receiving an identifier associated with
waste to be disposed of, and retrieving (based on the identifier)
information from a database. The information is derived from applicable
rules regarding disposal of waste items. The method further comprises
assigning the waste to a disposal category based on the information
retrieved from the database, locating a container associated with
the assigned disposal category, and facilitating disposal of the
waste item into the container associated with the assigned disposal
category.
In another embodiment, a method of sorting medical waste for disposal
comprises identifying a plurality of containers in a sorting station
and determining a waste category associated with each container,
identifying an item of waste to be disposed of, and assigning the
item to a waste category.
In another embodiment, a method of sorting medical waste comprises
identifying a plurality of containers in a sorting station and determining
at least one waste category associated with each container. The
waste categories are ranked from least to most hazardous. The method
further comprises identifying an item of waste to be disposed of,
and assigning the item to a first waste category. The method further
comprises determining whether a container associated with the first
waste category is present in the sorting station, and if one is
not present, re-assigning the waste item to a second waste category
that is ranked more hazardous than the first waste category.
In another embodiment, a method of sorting medical waste items
for disposal comprises identifying a plurality of containers in
a sorting station and determining a waste category associated with
each container. The waste categories are again ranked from least
to most hazardous. The method further comprises identifying an item
of waste to be disposed of, and assigning the item to a first waste
category. The method further comprises determining whether a container
associated with the first waste category is present in the sorting
station, and if one is not present, directing a user to another
sorting station which does have a container associated with the
first waste category.
In another embodiment, a system for sorting medical waste items
comprises a sorting station in electronic communication with a classification
database which lists a plurality of waste item identifiers distributed
into a plurality of waste categories. A plurality of containers
are positioned in the sorting station. Each container is sized and
configured to receive a plurality of medical waste items. A waste
item identification device is configured to receive a waste item
identifier from a waste item. A decision system is configured to
classify the waste item into a waste category using the waste item
identifier and information contained in the classification database.
Each of the containers is associated with one of the waste categories,
and the decision system is further configured to indicate into which
of the containers a waste item should be deposited based on the
waste category.
In another embodiment, a waste sorting and disposal system comprises
a sorting and disposal station comprising a waste item identification
device and a plurality of container compartments. The system also
has a database which comprises medical waste item classification
information derived from rules and regulations affecting the disposal
of medical waste items, and a plurality of containers positioned
in the container compartments. Each container comprises a machine-readable
identification key and an automatically operable door formed integrally
with the container. The station is configured to read each identification
key upon placement of a container in a container compartment, and
to selectively open and close the doors of each of the plurality
of containers.
In another embodiment, a system for sorting medical waste items
comprises a sorting station in electronic communication with a classification
database which lists a plurality of waste item identifiers distributed
into a plurality of waste categories. The waste categories are ranked
from least to most hazardous. A plurality of containers are positioned
in the sorting station, each container being sized and configured
to receive a plurality of medical waste items. A waste item identification
device is configured to receive a waste item identifier from a waste
item, and a decision system is configured to assign the waste item
to a waste category using the waste identifier and information contained
in the classification database. Each of the containers is associated
with at least one of the waste categories, and the decision system
is further configured to indicate into which of the containers a
waste item should be deposited based on the waste category. The
decision system is further configured to open a container associated
with a highest hazardousness level if the station does not include
a container associated with the assigned category.
In another embodiment, a system for sorting medical waste items
comprises a plurality of sorting stations in electronic communication
with one another via a central processing unit in a centralized
network. The sorting stations and the central processing unit are
often physically separated from one another. A classification database,
which lists a plurality of waste item identifiers distributed into
a plurality of waste categories, resides in the central processing
unit. Each sorting station comprises a plurality of containers,
and each container is sized and configured to receive a plurality
of medical waste items. A waste item identification device is configured
to receive a waste item identifier from a waste item, and a decision
system is configured to classify the waste item into a waste category
using the waste identifier and information contained in the classification
database. Each of the containers is associated with one of the waste
categories, and the decision system is further configured to indicate
into which of the containers a waste item should be deposited.
In another embodiment, a system for sorting medical waste items
comprises a plurality of sorting stations in electronic communication
with one another in a de-centralized network. The sorting stations
are physically separated from one another, and a classification
database resides on a data storage device in at least one of the
stations. The database lists a plurality of waste item identifiers
distributed into a plurality of waste categories. Each sorting station
comprises a plurality of containers, and each container is sized
and configured to receive a plurality of medical waste items. Each
container is designated as a specific type which defines a group
of items to be placed therein. A waste item identification device
is configured to receive a waste item identifier from a waste item,
and a decision system is configured to classify a waste item into
a waste category using the waste identifier and information contained
in the classification database. The decision system is further configured
to indicate into which of the containers a waste item should be
deposited.
In another embodiment, a method of sorting medical waste items
comprises joining a plurality of physically separated sorting stations
in electronic communication with one another in a network. The method
further comprises joining each sorting station in electronic communication
with a classification database which lists a plurality of waste
item identifiers distributed into a plurality of waste categories.
The method further comprises placing a plurality of containers in
each station, each container being sized and configured to receive
a plurality of medical waste items. The method further comprises
providing each station with a waste item identification device configured
to receive a waste item identifier from a waste item, and configuring
a decision system in each station to classify waste items into waste
categories using the waste identifier and information contained
in the classification database.
In another embodiment, a waste system comprises a station comprising
a waste identification device and a plurality of container compartments.
A plurality of containers are positioned in the container compartments,
and each container comprises a machine-readable identification key.
The station is configured to read each identification key upon placement
of a container in a container compartment.
In another embodiment, a waste system comprises a means for sorting
waste comprising a means for identifying waste and means for supporting
a container. Each one of a plurality of means for containing waste
comprises a means for machine identification of the means for containing
waste. The means for sorting further comprises a means for reading
each means for machine identification upon placement of a means
for containing in a means for supporting.
In another embodiment, a waste sorting and disposal system comprises
a sorting and disposal station comprising a waste identification
device and a plurality of container compartments A plurality of
containers are positioned in the container compartments, each one
comprising a machine-readable identification key which identifies
a waste category defining characteristics of the waste to be placed
in each container. The station is configured to read each identification
key upon placement of a container in a container compartment, and
the waste category of each container is independent of the container
compartment in which each container is positioned.
In another embodiment, a sorting system for separating waste into
a plurality of containers based on a classification of the waste
item is provided. The system comprises a plurality of containers,
each associated with at least one of a plurality of a waste categories.
A waste detector is configured to identify waste presented to the
detector. A sorting mechanism is configured to place waste into
one of the containers based on information received from the waste
detector. The system also comprises a sensor configured to determine
whether at least one of the containers has waste therein.
In another embodiment, a sorting system for separating waste into
a plurality of containers based on a classification of the waste
is provided. The system of this embodiment comprises a plurality
of containers, each associated with at least one of a plurality
of a waste categories. A database comprises waste classification
information derived from rules and regulations affecting the disposal
of waste items. A waste detector is configured to identify waste
presented thereto, and a sorting mechanism is configured to place
waste into one of the containers based on information received from
the waste detector. A sensor is configured to determine whether
at least one of the containers has waste therein.
In another embodiment, a sorting system is provided for separating
waste into a plurality of containers based on a classification of
the waste. The system comprises a plurality of means for containing
medical waste. Each of said means for containing medical waste is
associated with at least one of a plurality of a waste categories.
A means for identifying waste is provided, as is a means for sorting
waste into one of the means for containing using information received
from the means for identifying waste. The system also comprises
a means for determining whether at least one of the containers has
waste therein.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a schematic illustration of one embodiment of medical
waste sorting and disposal system including a plurality of interconnected
sorting and disposal stations in a centralized network;
FIG. 2 is a schematic illustration of one embodiment of medical
waste sorting and disposal system implemented in a decentralized
network;
FIG. 3 is a perspective illustration of an embodiment of a wall-mounted
sorting and disposal station;
FIG. 4 is a perspective illustration of one embodiment of a floor-standing
sorting and disposal station;
FIG. 5 is a front perspective view of one embodiment of a rolling
cart sorting and disposal station;
FIG. 6 is a rear perspective view of one embodiment of a rolling
cart sorting and disposal station;
FIG. 7 is a perspective view of one embodiment of a sorting and
disposal station incorporated into a rolling medications cart;
FIG. 8 is a rear perspective view of one embodiment of the cart
of FIG. 7;
FIG. 9 is an alternative embodiment of the cart of FIG. 7;
FIG. 10 is a partially exploded perspective view of one embodiment
of a sorting and disposal station comprising pivotable containers
and sleeves;
FIG. 11 is a perspective view of one embodiment of a sorting and
disposal station in the form of a convertible rolling cart in a
first configuration;
FIG. 12 is a perspective view of one embodiment of the convertible
rolling cart in a second configuration;
FIG. 13 is a perspective view of one embodiment of a disposable
container and portions of an interface with a sorting and disposal
station;
FIG. 14 is a perspective view of an alternative embodiment of a
disposable container and portions of an interface with a sorting
and disposal station;
FIG. 15 is a perspective view of an alternative embodiment of a
disposable container;
FIG. 16 is a perspective view of an embodiment of a disposable
container and an alternative embodiment of portions of an interface
with a sorting and disposal station;
FIG. 17 is a perspective view of an embodiment of a disposable
container and an alternative embodiment of portions of an interface
with a sorting and disposal station;
FIG. 18 is a schematic side elevation view of an embodiment of
a fill level sensor;
FIG. 19 is a block diagram of one embodiment of a fill-level detection
system;
FIG. 20 is a an overview flow chart of one embodiment of a software
algorithm for measuring a fill level of a container;
FIG. 21 is a detailed flow chart of one embodiment of a method
of measuring a fill level of a container
FIG. 22 is a continuation of the flow chart of FIG. 21;
FIG. 22A is an electronic schematic of one embodiment of an array
of light detectors, illustrated further in FIGS. 22A.sub.1-A.sub.5;
FIG. 23 is a block diagram of an alternative embodiment of a level
sensor system employing a video camera;
FIG. 23A is an electronic schematic of one embodiment of an alternative
embodiment employing a video system, illustrated further in FIGS.
23A.sub.1-A.sub.7;
FIG. 24 is a flow chart illustrating one embodiment of a sorting
algorithm for use by embodiments of a medical waste sorting and
disposal system; and
FIG. 25 is a flow chart illustrating a container-checking subroutine
for use by embodiments of a medical waste sorting and disposal system.
DETAILED DESCRIPTION
Waste Sorting and Disposal System
Embodiments of devices and methods for sorting a plurality of medical
wastes will now be described with reference to the attached figures.
In several embodiments, the waste sorting and disposal system is
automated. In some embodiments, a medical waste sorting system comprising
a plurality of individual sorting and disposal stations connected
to one another via a centralized or de-centralized network is provided.
Alternatively, a medical waste sorting system can comprise one or
more stand-alone sorting and disposal stations configured to operate
independently of any other device. Although some of the following
embodiments are described in the context of individual stand-alone
stations, it should be recognized that such individual stations
can be connected in a networked system to provide additional functionality
or to improve efficiency. Conversely, some embodiments are described
below in the context of networked systems, certain features and
advantages of which can be readily applied to individual stand-alone
systems as will be clear to the skilled artisan. The term "sorting"
is a broad term and shall be given its ordinary meaning and generally
refers to the distribution of one or more waste items into one or
more appropriate waste receptacles. The term "disposing"
is also a broad term and shall be given its ordinary meaning and
shall, in some embodiments, generally refer to the discarding or
"throwing out" of one or more items of waste into an appropriate
receptacle.
In one embodiment, a waste sorting and disposal station comprises
a sorting station or machine, which includes a series of container
positions or compartments, each compartment being configured to
receive a disposable container for collecting waste belonging to
a particular category or classification. Some embodiments of a sorting
station comprise a waste-identifying device, a processor configured
to carry out a waste-sorting algorithm, and a waste-sorting mechanism.
In some embodiments, a sorting machine comprises one or more sensors
for determining the presence of a container, a type of container,
and/or a volume or weight of a container. In another embodiment,
the sorting machine includes one or more sensors (e.g., an optical
sensor) to determine which container the item was deposited into
and/or a time at which an item is deposited. Additionally, a sorting
machine/station can include any of a variety of computer peripherals,
such as user input devices (e.g., touch screens, keyboards, pointer
devices, etc.), display devices, sound-producing devices (e.g.,
speakers or buzzers), or any other peripheral device.
In many embodiments, several container types are provided, each
type being associated with a particular category or classification
of pharmaceutical waste. For example, in some embodiments, container
types can include sharps containers, chemotherapy agent containers,
infectious waste containers, ignitable waste containers, hazardous
P-list waste containers, hazardous U-list waste containers, toxic
pharmaceutical waste containers, non-toxic pharmaceutical waste
containers, chemotherapy sharps containers, corrosive waste containers,
or reactive waste containers. Additional container types can also
be used as desired. In one embodiment, the container types are pre-designated
by the container provider. In other embodiments, the container types
are assigned by the hospital so that the hospital can individually
customize its waste sorting system. For example, some hospitals
may desire to define their own waste categories in order to comply
with internal goals, thus user-defined container types can also
be provided.
In a preferred embodiment, a waste identifying mechanism is provided.
In several embodiments, the waste identifying mechanism is configured
to identify a particular item of waste. Identification is preferably
accomplished prior to deposit into the appropriate container. Identification
of the waste item can be accomplished by scanning a barcode, reading
a label (e.g., using an optical scanner and Optical Character Recognition
software), reading a Radio Frequency identification (RFID) tag,
chemical sensors, spectroscopic analyzers, or by measuring or evaluating
any other qualitative parameter of the waste item presented for
identification. Alternatively still, an item of waste can be identified
by user input of information such as a trade name, a generic name,
a chemical name, National Drug Code (NDC) or other data associated
with a particular item of waste. For example, a user can simply
read a waste identifier from an item of medical waste and enter
the identifier into the system via a keyboard, touch screen or other
user input device.
In one embodiment, once an item of waste is identified, the sorting
algorithm determines to which of a plurality of waste categories
the item belongs. The station then indicates to the user which container
is associated with that category. For example, in some embodiments
the station indicates a correct container by opening a door providing
access to the container. Alternatively, such an indication can be
provided by illuminating a light or displaying a name or number
of a container on a display device. In some embodiments, a waste
sorting mechanism can carry out or instruct a user in delivery of
the waste item to the appropriate disposable container.
In some embodiments, the waste sorting mechanism comprises a plurality
of openings providing access to the plurality of containers. For
example, each of the containers can be configured to interface with
an automatically operable door or other means to present the container
opening to the user. Some embodiments of such an interface are described
in further detail below. Alternatively, the sorting machine can
be configured to provide access to an appropriate container in other
ways, such as by moving a container relative to the machine in order
to present a container opening to a user. In further alternative
embodiments, the sorting mechanism can include a series of lights
or other indicators configured to inform a user of the correct container
for a particular item of waste. Alternatively still, the sorting
mechanism can include an apparatus configured to receive an item
of waste from a user and physically convey the item to the appropriate
disposable container.
In some embodiments, a single waste item may call for disposal
in multiple containers. For example, a syringe might contain a quantity
of a hazardous or controlled substance, which requires disposal
in a first container. However, the syringe itself may require disposal
in a second, separate container. In such embodiments, it is desirable
for the system to determine an appropriate sequence for the disposal
of the separate parts of a single item. In the event that a waste
item contains information (such as a barcode or label) sufficient
to inform the system of the need for a sequence of disposal steps,
the system can determine the optimum sequence, and can then inform
the user of the appropriate sequence. The system may inform a user
of the appropriate sequence by sequentially opening appropriate
doors and/or by displaying instructions on a display screen. In
one embodiment, a means can be provided to determine whether an
item of waste is empty or contains residual or bulk hazardous or
non-hazardous contents.
Alternatively, it may be desirable for a user to determine the
best sequence for disposal, in which case, the user may enter information
into the system requesting a particular sequence. Additionally,
it may also be desirable for the system to include "shortcut
keys" in order to provide quick access to frequently-used containers,
such as sharps containers. Such shortcut keys can be configured
to quickly open a selected container.
In some embodiments, when a single waste item comprises a composite
of elements falling into different waste categories, such as a syringe
containing a controlled substance, which might, if disposed separately,
be sorted into two different containers, the waste sorting system
can indicate disposal of the composite waste item into the highest
hazard level container. In this manner, when it is inefficient,
ineffective or even dangerous to separate the single composite waste
item into its individual components, hospitals can still achieve
compliance by disposing of such hybrid or composite items into the
most conservative hazard container. In some embodiments, the containers
within a sorting station can be ranked in order from "least"
to "most" hazardous in order to facilitate a determination
of which container is the "most conservative" hazard container
in a given station. A determination of whether a particular container
type (and corresponding waste category or categories) is higher
or lower on a hazardousness spectrum can be determined by a variety
of suitable methods. In some cases, a hazardousness spectrum can
be determined empirically, while in other embodiments, the varying
degrees of hazardousness may be determined by comparing properties
such as relative reactiveness, bioactivity, etc. of elements of
a particular category.
In some embodiments, when a waste item is unrecognized by the identification
means, the sorting system will indicate disposal to the highest
hazard waste container. The system will notify the disposer that
the waste item was unrecognized. In another embodiment, the sorting
system may also notify a database or database personnel that the
waste item is unrecognized, thus facilitating a database upgrade
to include that waste item for future disposals.
In some embodiments of the invention, it may be advantageous to
determine the quantity of waste that has already been deposited
into one or more containers. In some embodiments, one or more sensors
are used to quantitatively assess one or more parameters of the
container and/or waste. These quantitative sensors include, but
are not limited to, sensors that detect the weight, volume, density,
and/or fill level of the waste in the container.
In one embodiment, one or more fill sensors are provided. A fill
level sensor can be used to monitor a fill level of each of the
disposable containers to determine when a particular container is
full. Once a container is determined to be full, the sorting system
can signal a user to replace the full container with a new empty
container. Additionally, once a particular container is full, some
embodiments of the system can be configured to determine the weight
or volume of waste material within the full container. The system
can also be configured to print a label to be affixed to the container.
The label can include a variety of information relating to the disposal
of the waste items, the quantity, weight or volume of the items
contained therein, a waste category name or code, etc.
In some embodiments, quantitative sensors are not used. Instead,
in one embodiment, the quantity of waste is determined by direct
visualization of the waste in a container. Transparent or translucent
containers are provided to facilitate visualization in some embodiments.
In several embodiments, the containers are opaque, but provide a
section or "view-strip" of translucent or transparent
material to permit visualization. In one embodiment, one or more
sensors are provided in conjunction with means to directly visualize
waste quantity. In one embodiment, means for detecting a quantity
of waste are not needed because the containers are replaced at regularly
scheduled intervals, as determined by a waste transport company,
a disposal company or hospital staff and independent of how much
waste is in any given container.
In some embodiments, when a new container is placed in a sorting
and disposal station, the system can be configured to identify the
new container according to the type of waste the container it is
permitted to hold. In some embodiments, a waste sorting and disposal
station can be configured to recognize containers in a static mode
in which each container position within the station/machine is associated
with a specific container type. Upon insertion of a new container
into the station, the system can recognize the type of container
and can determine whether the new container is the correct type
for the position in which it was placed. Thus, a system of this
type can insure that a consistent arrangement of container types
is maintained.
Alternatively, and more preferably, a sorting and disposal station
is configured to recognize container types in a dynamic mode in
which the machine is able to recognize and adapt to changing container
arrangements. Thus, according to this embodiment, each container
position/compartment in a station will recognize and accept any
new container regardless of the container type, and the software
will adapt a sorting routine to account for the new configuration.
In some cases, it may be desirable for a single station to have
multiple containers of a single type. For example, an oncology department
may desire several chemotherapy containers and no hazardous pharmaceutical
containers, while an area of the hospital that does not use chemotherapeutic
drugs may want several sharps containers and no chemotherapy containers.
This allows for substantial flexibility and customizability in system
set up. In further embodiments, a sorting and disposal station can
exhibit aspects of both static and dynamic systems, such as by allowing
any type of container in any container position, while requiring
a minimum number of containers of a particular type.
Network-Implemented System
In some embodiments, a waste sorting and disposal system can be
configured on a hospital-wide level by providing a plurality of
cooperating sorting and disposal stations throughout the hospital.
The system can include a plurality of individual sorting and disposal
stations in a variety of types, arrangements, sizes, functionalities,
etc.
FIG. 1 illustrates an exemplary embodiment of a centralized waste
sorting and disposal network. As shown, a centralized network 50
can include a main central unit 54 provided in electronic communication
with a plurality of smaller "satellite" units 60 throughout
a facility. In such a centralized network, the main unit 54 can
include a server containing the classification database 56 and any
other information to be shared with the satellite units 60. As information
is needed by a satellite unit 60, it can query the database via
the network in order to obtain that information. Alternatively,
or in addition, the main unit 54 can be configured to push updates
to the satellite units at regular intervals, or as new information
becomes available. In some embodiments, the main unit 54 can also
act as a central hub for various communications, tracking, maintenance
and other system functions.
FIG. 2 illustrates an embodiment of a de-centralized medical waste
sorting and disposal system. The network 64 of FIG. 2 is substantially
decentralized and comprises a plurality of sorting and disposal
stations 60 which can communicate with one another according to
any suitable method. For example, in a decentralized network, each
of the individual units may locally store a copy of the classification
database. In order to keep the classification database updated,
the individual units can share information with one another according
to any of a variety of peer-to-peer network protocols. The individual
stations can also share other information with one another as will
be further described below.
In either case (centralized or decentralized network), the network
elements can be configured to communicate with one another via any
suitable wired and/or wireless network communication protocol. Many
hospitals already have existing wired and/or wireless networks connecting
computers and communications devices throughout the facility. Thus,
in some embodiments, a networked medical waste sorting and disposal
system can be configured as an add-on to an existing network. Alternatively,
a networked medical waste sorting and disposal system can be configured
as an independent network. Additionally, the main unit (if present)
and/or the satellite unit(s) can further be connected to external
networks (e.g., the internet) via wireless or wired connections
as desired.
In some embodiments, it may be desirable for one sorting and disposal
station to have access to information about one or all of the other
stations in the network. For instance, it may be desirable for any
one station to determine an arrangement of containers in one or
more nearby stations. For example, if a clinician presents an item
of waste to a station which does not presently have a container
suitable for disposal of the presented item, that station can direct
the clinician to the nearest station that does have an appropriate
container installed. In further embodiments, a log of such re-directions
can be kept in order to increase efficiency by arranging the sorting
and disposal stations to include the most frequently used containers
for a given location.
Some embodiments of a waste sorting and disposal system are configured
to communicate information directly to a technician, maintenance
person, clinician or other person. For example, the system can be
configured to alert a maintenance person when a container is full
by sending an alert signal to a pager, cell phone, PDA, computer
terminal, or any other suitable device. The maintenance person can
then remove the full container and replace it with an empty container
(of the same or a different type).
Individual Sorting/Disposal Stations
A medical waste sorting and disposal station can take a variety
of forms depending on the specific needs of a given clinic, hospital,
department, clinician, etc. For example, some embodiments of sorting
and disposal stations 60 are illustrated in FIGS. 3-12. For example,
a station can be provided in a wall-mounted unit 60a (e.g., see
FIG. 3), in a floor-standing unit 60b (FIG. 4), on a wheeled cart
60c (FIGS. 5 and 6), attached to a patient bed, attached to an IV
pole, attached to an existing wheeled medications cart 60d (FIGS.
7-9), or any of a variety of other shapes, forms and mounting locations.
The embodiment of FIGS. 5 and 6 also includes a display device
70, a weight scale 72, a scanner 74 for identifying waste items
and a plurality of apertures 78 configured to reveal openings to
respective containers 80.
With reference to FIGS. 7-9, some embodiments of a station can
comprise a movable lid 82 with a single aperture 84. The lid 82
can be substantially flexible such that it can be driven to translate
above the containers in order to selectively provide access to any
one of the containers below the lid 82.
In some embodiments, the sorting machine can be configured to provide
access to an appropriate container in other ways, such as by tilting,
raising, lowering, pivoting, translating or otherwise moving a container
relative to the machine in order to present the container opening
to a user.
FIG. 10 illustrates an embodiment in which a sorting station comprises
a series of hinged sleeves 86 configured to pivot relative to a
fixed portion of the sorting station. Each sleeve 86 is generally
configured to temporarily house a disposable container 80. The station
60e comprises a series of actuators configured to pivot each sleeve
86 and its associated container 80 outwards, thereby exposing the
container opening 88. In one embodiment, an actuator 90 can be located
adjacent an upper portion of a container 80 and can be configured
to push the upper portion of the container outwards from the station.
Alternatively the sleeve 86 can be biased outwards by a spring or
simply by gravity, and an upper actuator can be configured to release
the sleeve/container to allow it to pivot outwards to open. The
upper actuator can then pull inwards to return the container/sleeve
to a closed position.
Alternatively or in addition, a lower actuator 92 can be provided
adjacent a bottom portion of the container/sleeve combination. In
one embodiment, a lower actuator 92 can comprise a drive axle 94
rigidly mounted to the sleeve 86. The axle 94 can be driven by a
motor or other mechanism in order to pivot the sleeve 86 inwards
and outwards. A container 80 can be inserted into the sleeve 86
and pivoted back so that a fixed portion of the station 60e covers
the container opening 88. During use, the actuator 90 or 92 causes
the sleeve 86 to pivot outward from the station 60e, thereby exposing
the container opening for use. The container 80 can be removed by
sliding it out of the sleeve 86. In an alternative embodiment, the
above system can be provided without a sleeve 86 by incorporating
an actuator and a pivot point into the container itself. In further
alternative embodiments, other actuators, drive mechanisms, etc
can be used in order to selectively provide access to a container
opening.
In another embodiment, the station can be configured to house each
of the containers in a sliding drawer. The drawers can include actuators
configured to move the drawer outwards until an opening is exposed.
The containers can then be easily removed once they are full.
FIGS. 11 and 12 illustrate another embodiment of a waste sorting
and disposal station 60f in the form of a convertible rolling cart.
In a first orientation, illustrated in FIG. 11, the station 60f
is a two-sided rolling cart. The station 60f of this embodiment
can be provided with a hinge 96 configured to allow the two sides
98a, 98b of the cart 60f to unfold into a one-sided arrangement.
In this second configuration (shown in FIG. 12), the station can
be mounted or placed against a wall.
In some embodiments, a sorting and disposal station 60 can include
a scale configured to determine a weight of a full container. Thus,
a scale 72 can be provided on an upper or other accessible portion
of the station. Alternatively, the station can include a scale (e.g.,
a load cell) to continuously or repeatedly weigh each container
within the station. Such information can be useful in creating a
manifest for the containers before transportation of the containers
to an appropriate disposal facility. Additionally, or alternatively,
a station can include a fill level sensor for continuously or intermittently
determining a fill level of a container. Embodiments of a fill-level
sensor are described in further detail below.
Disposable Containers
In some embodiments, the disposable containers are generally designed
to be low cost, yet include features that provide a functional interface
with mechanisms in a sorting station to perform several desired
functions. For example, in some embodiments, each container includes
a door or lid which can be opened and closed automatically in order
to allow or prevent access to a particular container at a particular
time. Additionally, the containers can be configured to interface
with sensors for determining a quantity of contents within the container,
and/or sensors for determining a type of container.
In some embodiments, the containers 80 are blow molded (or otherwise
formed) from polypropylene, high molecular weight polyethylene,
polyvinylchloride or any other suitable plastic or other material
as desired. In some embodiments, the containers 80 have substantially
frosted or translucent side walls. The containers will typically
be sized to have an internal volume of anywhere from 1 to 20 gallons,
however greater or smaller volumes can also be used as desired.
For example, in some particular embodiments, containers can be provided
in 1-gallon, 3-gallon and 8-gallon sizes.
The shape of the containers can vary widely. In some preferred
embodiments, the containers include a lifting handle, a primary
opening which can be automatically and/or manually closed or sealed,
and a bottom surface configured to allow the container to stand
upright. Additionally, the disposable containers can also include
features such as an automatically-openable door or lid, a manually
closable lid, features for accurately locating the container in
a container compartment of a station, a viewing window for visually
verifying a fill level, and/or identification information for informing
a user of a container's contents (or intended contents).
The containers can be provided with an opening 88 having a variety
of shapes and/or features. For example, in one embodiment, the opening
88 is substantially circular and has a minimum internal diameter
of at least about three inches (.about.76 mm). In other embodiments,
the opening 88 can be substantially elliptical, rectangular, polygonal
or otherwise shaped, and can be any suitable size, including sizes
smaller than three inches in diameter. The particular type or types
of waste to be deposited in a particular container can be a significant
factor that can be used in determining a suitable size and/or shape
of a container opening. In general, the container opening should
be sized to easily accept the largest waste item that is expected
to be deposited in the container. For example, some containers might
receive full or partially full liter-sized IV bags, gallon-sized
biohazard bags or other large items. It is generally desirable that
the container opening be configured to accept these large items
easily and without tearing the bags or otherwise damaging or causing
spillage of a waste item. The skilled artisan will recognize that
other factors may also affect a choice of container opening size
or shape.
In some embodiments, disposable containers are provided in a plurality
of types, each type corresponding to a respective waste category
or waste classification. In order to allow clinicians, maintenance
people, and any other persons who may handle the containers to quickly
and easily differentiate containers of various types, the containers
can be color-coded to correspond with a particular type or category
of waste. In some embodiments, a color-coding scheme can be selected
to match industry standards for various types of medical waste.
Red, for example, typically signifies infectious waste, while yellow
typically signifies chemo therapy drugs. Color-coded containers
can advantageously simplify the tasks associated with manual transportation
and processing of the containers, and can aid in insuring that such
tasks will be handled correctly for each waste stream.
Alternatively, such visual verification of a container's type can
be provided by any other suitable method. For example, the various
container types can be indicated by labels bearing numeric, alphanumeric,
graphical or symbolic information. Such labels can include printed
stick-on labels or various features molded or formed directly into
portions of the containers themselves. If desired, such type-identification
features can be provided in addition to color-coding of the containers
in order to further simplify identification of a container's type.
Providing simple visual verification of a given container's type
advantageously simplifies and facilitates handling of medical waste
materials throughout many aspects of collection and disposal.
In some embodiments, the containers can be configured in such a
way that a sorting and disposal station can automatically identify
a type of container. Such automation allows a station/machine to
detect the mix and arrangement of container types in the station
at any given time. In some embodiments, each container includes
an identification key that can be read by corresponding structures
in a sorting station. The key generally allows the sorting station
to automatically identify the type of each container occupying a
compartment or container position within the station. As discussed
above, the station can be configured to identify container types
in either a static or dynamic mode depending on a desired degree
of flexibility for a given station.
Identification keys may be physical features such as fingers molded
into or attached to each container. Alternatively, identification
keys can be holes, notches, or grooves molded or cut into a portion
of each container. In some embodiments, identification keys include
optically-readable features such as holes, dark or light colored
dots, text, symbols, graphics, etc. A physical key may be configured
to be read by mechanical or optical switches associated with each
compartment or container position within the station. For example,
FIG. 13 illustrates an embodiment of a container 80 with an identification
key 104 made up of a series of holes 110 in a flange 112 extending
from an upper portion of the container 80. The holes 110 of FIG.
13 can be detected by a plurality of optical switches 138 mounted
to a portion of the station adjacent a container position. Thus
the various container types can be identified by providing holes
(or other features) in varying combinations and positions.
Alternatively, a key may be an optical mark, such as a bar code,
that can be interpreted by a sensor such as a bar code reader. Alternatively
still, the key may be a radio frequency identification (RFID) tag
that can be read by a transponder associated with each compartment.
In still further embodiments, container identification keys can
comprise microchips, magnetic strips, or other electronic media
that can be read by a waste sorting and disposal station into which
the container is placed. In one alternative embodiment, a polychromatic
sensitive optical sensor can be provided to directly determine a
color of a container.
As discussed above, some embodiments of a disposable container
are provided with automatically operable doors. In such embodiments,
a container can be closed by default to prevent insertion of items
into an incorrect container. Then, once an item is scanned or otherwise
identified, the station can open the appropriate container or otherwise
signify the single correct container to receive that particular
waste item.
FIGS. 14-17 illustrate embodiments of containers comprising integrally-formed
automatically operable doors and corresponding structures in a sorting
station. The illustrated structures are generally configured to
provide an automated interface between a container 80 and portions
of a sorting and disposal station in order to allow the station
to automatically recognize and operate a container. According to
these illustrated embodiments, each compartment includes an actuator
mechanism configured to automatically and selectively open and close
the corresponding container 80. The selective opening and closing
of each container may be accomplished via interaction of structures
on both the disposable container and the station, and can ultimately
be controlled by a computer system within the sorting and disposal
station.
In some embodiments, a container may include a movable lid molded
or otherwise joined to the container opening. The lid can generally
be configured to pivot, slide, hinge or rotate relative to a container
in order to reveal or cover the container opening. In some embodiments,
the lid is configured to mate with a mechanical actuator in the
station upon installation of the container in a given container
compartment. The actuator can be configured to cause the lid to
open and close by translating, rotating or pivoting the lid. The
actuator and lid can be further configured to separate from one
another when the container is removed from the station.
FIG. 13 illustrates one embodiment of an interface between a container
80 and portions of a sorting station. In the illustrated embodiment,
the container 80 comprises a gate 116 covering an opening 88 and
configured to slide in tracks 118 between an open position and a
closed position. The gate 116 can include a latch 120 configured
to lock the container opening when the gate 116 is completely closed.
When a new container 80 is inserted into a station, a drive pin
122 on the gate control arm 124 is engaged by the gate 116 of the
container. The control arm 124 is configured to open and close the
gate 116. The gate control arm 124 can be coupled to a drive motor
128 via a transmission element such as a disc 132 or a similarly
functioning arm. If desired, a position switch 134 can also be provided
on the disc 132, control arm 124, gate 116 or other component in
order to detect a position of the gate 116. In the illustrated embodiment,
the position switch 134 is an optical switch configured to detect
one or more holes 136 in the disc 132. Additionally, the sorting
station can include a plurality of optical switches 138 for detecting
the presence of a container and/or the type of container 80 inserted
into the sorting station. The embodiment of FIG. 14 replaces the
gate control arm 124 of FIG. 13 with a slot 140 in the gate 116
in order to convert the rotational motion of the pin 142 extending
from the disc 132 into linear motion of the gate 116.
In alternative embodiments, other configurations of automatically
openable doors/gates can be provided For example, FIG. 15 illustrates
an alternative embodiment of a container comprising a sectioned
door 150 configured to slide along tracks 152 extending from the
exterior surface of the container 80. The slidable lids of the above
embodiments can be provided with a latch (such as that shown in
FIGS. 13 and 14) which can be automatically engaged in order to
lock the container once a sorting station determines the container
is full. The embodiment illustrated in FIG. 16 can include a slidable
door 116 driven by a rack and pinion drive mechanism 156. Alternatively,
the drive mechanism 156 of FIG. 16 can comprise a driven friction
wheel configured to engage a portion of the slidable lid 116. A
similar pinion or friction wheel drive system can be used to automatically
operate the sectioned door 150 of the embodiment shown in FIG. 15.
FIG. 17 illustrates an embodiment of a container 80 with a lid 158
configured to open by pivoting relative to the container 80. In
further alternative embodiments, a door can be opened or closed
by any of a variety of other mechanisms. For example, worm screws,
pneumatic pistons, hydraulic pistons, solenoids, or any other motion-transferring
mechanism can be used to selectively open and close a container
door.
In some embodiments it may also be desirable to provide an outer
lid configured to seal a container opening once the container is
full. The outer lid is preferably configured to attach to the container
sufficiently securely to prevent spillage or tampering. An outer
seal also shields users from contaminants that may have come in
contact with the container top area during use. For example, in
some embodiments a flexible lid can be configured to seal over a
top of the automatically actuated door by frictionally engaging
a lip, groove, or other structure in a manner similar to many flexible
lids used in food storage containers. In alternative embodiments,
outer seals can be provided in the form of a bag or shrink-wrap
material that surrounds a substantial portion of a container's exterior.
In some embodiments, it may be desirable to provide a container
configured to render waste items non-recoverable by providing a
substance within an "empty" container that can react chemically
with waste items. In another embodiment, a solidifying agent can
be provided within a container in order to solidify non-hazardous
pharmaceuticals allowing for their disposal in a landfill. In some
embodiments, such solidifying agents can include materials capable
of absorbing a quantity of a liquid non-hazardous pharmaceutical
material. For example, such absorbent materials can include ceramic
materials, sponge materials or other porous materials. Alternatively,
such solidification may involve a chemical reaction between the
waste material and a substance provided within the container.
Fill-Level Detection System
In some embodiments, it is desirable to measure a fill level of
waste within a container throughout the sorting and filling process.
In some embodiments, such fill level sensing can be performed by
measuring a weight of a container, such as by using a load cell,
balance, or other weight measurement device. In further embodiments,
float systems can be adapted for use in determining a level of a
waste material in a waste sorting system. In some cases, it is also
desirable to perform such fill level measurements without the sensor
physically contacting the container or the container contents.
In some embodiments, a piezo transducer can be used to determine
a volume of air remaining in a container by conducting a frequency
sweep of the transducer to determine the resonance of the air in
the container. Once the volume of air in the container is known,
the air volume can be subtracted from the known total container
volume to obtain the volume occupied by the container contents.
In another alternative embodiment, a distance-measuring sensor (such
as SONAR, RADAR or optical distance-measuring sensors) can be located
above and directed through the opening of the container in order
to determine a "height" of the container contents. In
another embodiment, a sensor can be provided for determining whether
a container includes any waste at all. Such a "waste presence"
sensor can be used in combination with a timer to determine a replacement
schedule for a particular container based on a maximum acceptable
dwell time for a particular waste item in a container. Still other
embodiments may use optical sensors to measure a fill level of a
container.
FIGS. 18-19 illustrate one embodiment of a level sensor which can
be used to automatically determine a fill level of a container using
an optical method. As shown in the schematic illustration of FIG.
18, one embodiment of a fill level sensing system comprises a light
source 230 and a light detector 232 positioned on opposite sides
of a disposable container 80. In alternative embodiments, the light
detector 232 need not be located immediately opposite the light
source, for example, in some embodiments the detector can be located
on a wall adjacent to the source 230. The sensor system of FIGS.
18 and 19 generally operates on the principle that an "empty"
container will permit more light to pass from the source, through
the container, and to the sensor than will a "full" container.
This is simply due to the fact that the contents of the container
80 will absorb and/or reflect a substantial portion of the light
which enters the container from a light source.
As used herein, the terms "empty" and "full"
shall be given their ordinary meaning and shall be used to define
relative amounts of debris, or other matter, in a container. For
example, in certain embodiments, the sensor may indicate that the
container is ready to be emptied or discarded, not because it is
completely saturated, but because it has reached the desired point
of fill or saturation. In some situations, it may be desirous to
empty or remove a container when anywhere from about 1% to about
100%, often from about 25% to about 100% of that container contains
waste material. In other situations, it may be desirable to remove
a container when about 50% to about 95% of its volume is occupied
by waste material.
In some other embodiments, a parameter other than weight or filled
volume may be used to determine when a container is "full."
For example, in one embodiment, a sensor to detect radioactivity
is used to determine the amount of radioisotope in a container or
receptacle. The radioactivity sensor may used in connection with
a fill sensor, or it may be used alone. Thus, in some embodiments,
a container may be emptied, discarded, or replaced based on a certain
amount of radioactivity, rather than (or in addition to) the surface
area, volume, weight, density and/or another parameter of the material
in that container.
In yet another embodiment, a sorting and disposal system can be
provided without any automatic level detection apparatus. For example,
in such an embodiment, the containers can be configured to allow
a clinician, maintenance person, or other user to visually verify
a fill level of the container. In such embodiments, the containers
can be made of a substantially transparent or translucent material.
Alternatively, the containers may be substantially opaque but can
include a transparent viewing window to allow visual verification
of a fill level. Such viewing windows could extend substantially
an entire height of the container, or could extend only a height
of a desired portion of the container.
In some embodiments, the source 230 and detector 232 are located
along a "fill line" which generally defines a "fill
plane." The fill plane 240 is generally the level within the
container 80 which a processor 242 defines as "full."
In some embodiments, the actual free surface of contents within
a container may not necessarily be planar. In such embodiments,
the "fill plane" used by the processor and fill level
sensing system is simply an average height of the material.
In the embodiment illustrated in FIG. 18, a light source 230 is
located at a "front" of the container and a detector 232
is located at a "rear" of the container. In alternative
embodiments, the positions of the light source 230 and detector
232 can be reversed, or positioned at any other position around
the container 80. In still further embodiments, multiple sources
and/or detectors can also be used as desired.
As discussed above, the containers 80 are typically made of a translucent
material which allows at least some amount of light to pass through
its walls. The embodiments of a fill level sensor illustrated in
FIGS. 18 and 19 are particularly advantageous when used to measure
a fill level of a container with translucent sidewalls. However,
the skilled artisan will recognize that certain advantages of the
embodiments described herein may be advantageously applied to systems
using containers having transparent sidewalls or containers with
transparent windows in otherwise relatively opaque sidewalls. As
used herein, the term "translucent" is used in its ordinary
sense and refers without limitation to a material which allows the
diffuse transmission of light when illuminated, while remaining
substantially non-transparent when not illuminated.
The light source can comprise any suitable source of light such
as incandescent bulbs, white or colored LED's, or other sources.
In some embodiments, the light source 230 is located such that it
is vertically centered on a desired "fill line" 240 of
the container. The light source can be laterally centered relative
to the container, or can comprise a width that is about as wide
as the container 80. In still further embodiments, a plurality of
light sources can be used to illuminate a container from multiple
points.
As illustrated in FIG. 19, the light detector 232 can comprise
an array of photo detectors 236 such as cadmium sulfide photo detectors
or photodiodes. In the illustrated embodiment, the array of photo
detectors 236 comprises three rows 244, 246 and 248 of detectors
236. The upper row 244 contains a single detector 236 while the
middle 246 and lower 248 rows contain a plurality of detectors 236
(three in the illustrated embodiment). In alternative embodiments,
the upper row 244 can be provided with additional detectors which
equal or exceed the number of detectors in the other rows. Similarly,
the middle 246 and lower 248 rows can include fewer or more than
three detectors as desired. The number of detectors in each row
will typically be determined by the algorithm used to determine
the fill level of the container and/or the degree of accuracy desired.
In some embodiments, it may also be desirable to provide more than
three rows of detectors. For example, in some embodiments, a fill
level detection system can be provided with four, five or more rows
of detectors.
In some embodiments, the middle row of detectors is positioned
to lie just above the fill line 240 of the container 80, and the
lower row 248 of detectors 236 is positioned just below the fill
line 240. The upper row 244 of detectors 236 can be located substantially
above the fill line, and can be used to calibrate the detectors
middle 246 and lower 248 rows as will be described in further detail
below.
In some embodiments, the upper and middle rows can be spaced by
a distance 250 of between about 1/2'' and about 2 inches, in other
embodiments the upper and middle rows can be spaced by a distance
250 of between about 1 inch and about 11/2 inches, and in one particular
embodiment, the upper and middle rows are spaced by a distance 250
of about 11/4 inches. Similarly, the middle and lower rows can be
spaced by a distance 252 of between about 1/2'' and about 2 inches,
in other embodiments, the middle and lower rows can be spaced by
a distance 252 of between about 1 inch and about 11/2 inches, and
in one particular embodiment, the middle and lower rows are spaced
by a distance 252 of about 11/4 inches. In some embodiments, the
detectors 236 of the middle 246 and lower 248 rows are spaced horizontally
by a distance 254 of between about 1/2 inch and about 3 inches,
in other embodiments, the detectors 236 of the middle 246 and lower
248 rows are spaced horizontally by a distance 254 of between about
1 inch and about 2 inches, and in one particular embodiment by a
horizontal distance 254 of about 11/2 inches. In some embodiments,
the sensors are evenly spaced, while in other embodiments, the sensors
of the middle row are horizontally spaced differently than the sensors
of the lower row. In further alternative embodiments, the spacing
of the detectors 236 can be determined by factors such as the size
of the container or the material to be placed within the container.
In operation, the individual photo detectors 236 pick up light
transmitted through the container and output corresponding signals
to a processor 242. On one hand, the light intensity arriving at
the detectors 236 depends on the fill level of the container 80.
In addition, a number of secondary factors also effect the light
intensity reaching the detectors 236. These include the strength
of the light source 230, the color and opacity of the container
80, the amount of ambient light, and other factors such as dust
in the air. The light intensity at the top detector row 244 is almost
completely governed by these secondary factors, since it is located
well above the fill line 240. By contrast, the light intensity arriving
at the middle 246 and lower 248 detector rows will be effected more
by the fill level of the container contents as the container 80
becomes more full (e.g., as the fill level approaches the fill line).
When the container 80 is empty and the overall light intensity
is greatest, a baseline reading is recorded and calibration coefficients
are generated for each of the detectors 236 and detector rows 244,
246, 248. As the container fills, the received light reaching the
detectors decreases slightly as material in the container blocks
a portion of the diffused light transmitted through the container
80. During this phase, the top detector reading is used to compensate
the readings of the middle and lower detector rows accordingly.
When the container contents reaches the fill line, the bottom row
of detectors will be blocked by the container contents, while the
middle 246 and upper 248 detector rows remain unobstructed. This
results in a substantial drop in the light intensity reaching the
bottom row 248 of detectors, and correspondingly, a substantial
difference in signal strength between the middle 246 and lower 248
detector rows. When this signal difference reaches a pre-determined
threshold level, the processor determines that the container is
"full."
In some embodiments, the items being deposited into a container
may be stacked unevenly or oddly oriented within a container so
that the contents of a container vary from a neat horizontal fill
level. For example, some large items, such as syringes or other
contaminated medical devices, may stack oddly within a container,
thereby creating voids of unfilled space in a central portion of
a container, above which waste items may be stacked. Such variations
in filling can lead to lead to measurement errors. Thus, in some
embodiments, a level sensing system can be provided with error processing
capabilities to account for variations in orientation and/or uneven
loading of a container.
For example, in some embodiments, the signals from the plurality
of detectors in each row are averaged to provide a consensus value
for the respective detector row. This advantageously allows the
processor to determine an average fill level in the event of an
uneven fill surface. For example, in an idealized case, a container
filled with a plurality of spherical particles through a hole in
the top center of a regularly-shaped container will typically have
a free surface in a shape of a cone with a peak at the center, and
dropping off evenly in each direction. In such a case, the center
detector of the lower row 248 will typically receive a lower light
intensity than the detectors on either side. Thus, by using the
data from all of the detectors in a horizontal row, a processor
can calculate an approximate average fill level in order to prevent
over-filling of the container.
These or other error-processing techniques can also be used to
compensate for manufacturing defects in a container that might result
in erroneous results. For example, if a plastic container wall comprises
an air bubble or a dark spot in a region adjacent one or more of
the detectors, these abnormalities could cause erroneous readings
by those detectors. To compensate for this, a system may give less
weight (or no weight at all) to signals from detectors that are
out of a statistically expected range of variation from the remaining
detectors. By taking an average signal across all detectors in various
combinations and/or by assigning varying weights to individual detectors,
a control algorithm can teach itself to recognize and adapt to such
error-causing situations in order to obtain consistent readings.
In some embodiments, the functionality of a fill level sensing
system employing a light source and a plurality of optical detectors
can advantageously be enhanced by containers with "frosted"
or translucent walls. Another advantage of certain embodiments of
a level sensing system as described herein is that such systems
can be polychromatic sensitive (i.e. configured to sense light of
various colors with consistent accuracy). Thus, in addition to measuring
a fill level of a container, the above-described sensors can be
configured to determine a color of a container (each container color
being associated with a particular container type as discussed above).
In some embodiments, these and other advantages are achieved through
the use of cadmium sulfide photosensitive cells. In alternative
embodiments, optical level sensors can be constructed using other
optical detectors, including other photoconductive cells, photo
diodes, or other sensors capable of detecting light in the visible
or infrared spectrum.
In some embodiments, each one of a plurality of fill-level sensors
is controlled by a single processor in a waste sorting system. In
one embodiment, a plurality of photo detector arrays can be connected
to a single multi-channel bus, and a plurality of light sources
can be controlled by a processor. In this embodiment, the processor
can illuminate a single container at a time. Thus, the detectors
behind each of the "dark" containers would be at high
impedance, and would therefore be out of the circuit.
In some embodiments, a fill level sensing system employing optical
sources and detectors can include an additional photo detector that
is generally configured to measure changes in "ambient"
light within the system in order to appropriately adjust the readings
from the detector arrays measuring fill level. An ambient light
detector can comprise a single optical detector, or a plurality
of detectors in a circuit. In one such embodiment, an additional
ambient light detector is provided within a waste sorting system
in a location selected to measure any light entering the system
from the exterior of the sorting system. For example, the ambient
light detector can be located adjacent a container-replacement door
or any other portion of the system that is open to external light.
FIG. 22A illustrates one embodiment of a circuit schematic which
can be used in building an optical fill level sensor such as that
illustrated in FIGS. 18 and 19. The skilled artisan will recognize
that this is merely one exemplary schematic, and that alternative
embodiments of the system of FIGS. 18 and 19 can be built using
any appropriate components.
FIGS. 20-22 are flow charts illustrating embodiments of software
algorithms used by a level detector for use in a sorting system.
FIG. 20 is a flow chart illustrating an overview of a level testing
algorithm. When the system determines that a new container has been
inserted, the level sensor establishes new baseline values for the
detectors in order to define the "empty" state. The level
sensing system then reads values of the detectors 236 and inputs
the detector values to an inference engine (FIGS. 21 and 22).
The inference engine can use a "fuzzy logic" method similar
to the Sugeno method. In one embodiment, the inference engine uses
a table of empirically-determined data to establish rule weights.
The inference engine can also use multiple grouping of detectors
in addition to individual detector levels to calculate a final fill
level of the container. In some embodiments, the empirically-determined
lookup table can be developed by performing various calibration
experiments using an optical level sensing system to measure containers
at known fill levels. In addition to any controlled experiments,
the lookup table can be supplemented by analysis of information
it receives during use in measuring fill levels of new containers.
For example, as optical anomalies are detected and accounted for,
the software can adapt to correct for them.
FIGS. 21 and 22 are flow charts illustrating one embodiment of
an inference engine. In order to avoid misleading readings during
filling, the system can be configured to determine when the detectors
are at a steady state (e.g., when the movement of waste within the
container drops below a threshold level). This is particularly helpful
in embodiments in which a waste material is a liquid, and thus may
continue moving for a period of time.
Once steady state is reached, the inference engine compares the
values of the detector readings and ultimately derives a final fill
value which can be stored and/or output to a user-readable device
such as a liquid crystal display. In alternative embodiments, an
output of the system can include other visible, audible or tactile
alerts, such as LEDs, buzzers, bells, vibrators, etc. In some embodiments,
an output signal is used to notify the user that a particular container
is ready to be emptied, discarded, replaced etc. In an alternative
embodiment, an output signal is provided substantially continuously
or at various intervals, so that the user can determine or monitor
the amount of material in a given container at any given time. For
example, in some embodiments, the fill-level of a container can
be measured at regular intervals, such, as every ten minutes, every
hour, every two hours, every six hours, every 12 hours, or every
24 hours. In still further embodiments, the system can comprise
a sensor (such as an optical sensor) to determine when an item is
deposited into a container. Then a fill-level of the container can
be measured after each item is deposited in the container.
FIG. 23 illustrates an alternative embodiment of a video fill level
sensing system. The embodiment of FIG. 23 employs a camera 270 to
continuously detect an intensity of light exiting the container
from the source. In the illustrated embodiment, a light source 270
is positioned to illuminate the container 80, and a curved mirror
274 and pinhole video camera are located adjacent another side of
the container 80. The system can also include a software-based processor
276 and other electronic hardware. In the illustrated embodiment,
the light source 270 is located adjacent one vertical side of the
container 80 and the camera and mirror are positioned on the opposite
side of the container. In alternative embodiments, the light source
270 and camera/mirror assembly can be located on adjacent sides
of the container 80. Alternatively still, the light source 270 can
be located above the container such that light is directed downward
into the container, thereby allowing the waste to absorb as well
as reflectively diffuse the light source onto the walls of the container
80.
In some embodiments, the camera 270 is directed at the mirror 274
to detect light emitted from the container 80 and gathered by the
mirror 274. The curved mirror 274 provides a linearization of scanline
width by distorting the optics of the camera. In one embodiment,
the camera 270 is a pinhole camera, which is selected due to the
depth of field this type of lens provides. In one embodiment, the
curved mirror 274 has a shape substantially similar to a shoehorn,
e.g., it is curved about two perpendicular axes (e.g., longitudinal
and transverse axes). Alternative mirror configurations can also
be used as desired. The particular curvature of the mirror 274 is
determined empirically depending on the width of scanline needed
and the height of the measured area (e.g., the height of the container
wall). Variation in the curvature of the mirror along its length
allows the scanline to be optimized in order to emphasize areas
of higher interest and to de-emphasize lower interest areas. The
mirror can be convexly curved at the height of higher interest areas,
and concavely curved to de-emphasize lower interest areas.
In some alternative embodiments, the light source can include bands
of varying color or intensity along the height of the container
in order to provide emphasis to portions of the container, or to
provide "watermark" levels that can be measured against.
In some embodiments, the software can be configured to interpret
information received from the camera to learn about points of interest
in order to further optimize a measurement algorithm. For example,
rather than programming an algorithm to anticipate areas of higher
or lower interest, the algorithm can be configured to recognize
variations in light intensity during calibration in order to detect
such areas of higher or lower interest.
The processor and its support hardware provide the sampling of
multiple luminance intensities along the wall of the container 80
adjacent the mirror 274. The analog video signal is amplified and
ground-referenced by the video amplifier. This amplified signal
is scanned for a selected scanline to digitize for quantifying its
luminance value. The amplified video is also applied to the Sync
Separator module, which produces timing pulses for the scanline
selector module. The processor receives the scanline data from the
scanline selector, digitizer and sync separator. The video level
sensor can determine a current fill level of the waste in the container
80 using a similar software method to that described above with
reference to FIGS. 18 and 19. FIG. 23A illustrates one embodiment
of a circuit schematic which can be used in building a video fill
level sensor such as that illustrated in FIG. 23. The skilled artisan
will recognize, however, that this is merely one exemplary embodiment.
In alternative embodiments, the system of FIG. 23 can be built using
any appropriate components.
Many of the above embodiments of fill level sensors were described
with reference to a single disposable container. In some alternative
embodiments, it may be desirable to provide a single fill level
detection system configured to selectively measure a fill level
of any one of a plurality of containers. For example, in one embodiment,
a light source may be provided on a first side of a plurality of
containers, and a light detector can be movable into a position
opposite the light source of the containers. In one embodiment,
this may take the form of a circular arrangement of containers in
which a light detector is located at a center of a circular arrangement
of containers. One or more light sources can be positioned on an
outer portion of the circular arrangement such that the light source
and/or the light detector is capable of measuring a fill level of
each one of the plurality of containers around the circle.
In some embodiments, the sorting system can also include a weight
scale (such as a load cell, pressure transducer, mechanical scale
or other device) configured to weigh either a single spent drug,
container or individual segregated spent drugs. In one embodiment,
the information from the scale can be sent to a printer providing
a means for printing a manifest for the container. Additionally,
such information could be combined with other information available
to a clinician in order to determine a quantity of a drug or substance
that has been used or consumed. Many hospitals are automating the
dispensing of drugs. The automation is usually embodied in a piece
of equipment that a doctor or nurse accesses with a patient and
clinician code and the correct amount of drug is dispensed. The
automation provides pharmacists, nurses, doctors and administrators
with information from a database on what drugs are dispensed and
to which patient. These systems can typically indicate how much
of a drug was administered, but entering this information typically
requires a clinician to return to the dispenser (which may be inconvenient,
and thus not done regularly). This information can be quite useful
because it will demonstrate any inefficiencies or mistakes in administrating
the drugs as well as point out any theft of drugs. In some embodiments,
a sorting and disposal system can be configured to track dispensing
information because at the point of throwing the spent drug away,
they are automatically providing information to a central database.
Sorting Algorithm
Embodiments of a pharmaceutical waste sorting and disposal system
will generally employ a waste sorting algorithm to assign each item
of waste to a particular waste category and correspondingly to a
particular waste container. A waste sorting algorithm can take a
variety of forms, and can include a range of functionalities.
In some embodiments, as discussed above, determination of the waste
categories themselves can depend on a number of factors, including
RCRA hazardous waste definitions, state and federal EPA regulations,
OSHA regulations, and any institution-specific regulations. For
example, RCRA definitions generally include a P list, a U list and
four characteristics of hazardous waste: ignitability, corrosivity,
toxicity and reactivity. Materials exhibiting each of these characteristics
typically call for different handling, treatment and/or disposal.
Thus, in some cases waste categories can be defined based on groups
of materials that require the same or similar handling, treatment,
or disposal. However, in some cases, two materials that may be handled
and/or treated in a similar manner might react adversely if they
are combined with one another. Thus, in further embodiments, determination
of the waste categories can also depend on the combinability of
materials exhibiting one or more of the above characteristics.
Once a series of unique waste categories is established, lists
of known pharmaceuticals, chemicals, materials and waste items can
be selectively assigned to at least one of the waste categories.
In some embodiments, as discussed above, when a waste item is presented
to a sorting station, the item is identified according to a waste
item identifier. Such identifiers can include a trade name, a generic
name, a National Drug Code (NDC), one or more components or ingredients
of the item, or any other sufficiently unique or relevant waste-identifying
datum. Thus, a category database can be developed which correlates
a number of known waste identifiers with respective waste categories
according to existing federal, state, local, institution-specific
or other rules and regulations.
In some embodiments, it may also be desirable to provide a database
which lists ingredients of a plurality of known pharmaceuticals
or other chemicals that have not yet been correlated to a waste
category by the category database. Such an ingredient database can
be used by the sorting algorithm in an intermediate step between
identifying an item and assigning the item to a category on the
basis of one or more ingredients. In some embodiments, an ingredient
database may reside within the waste sorting and disposal system.
In alternative embodiments, an ingredient database can reside at
a remote location, such as on a server operated by a manufacturer
of a particular item, or another remote location. The waste sorting
and disposal system can be configured to access such remote databases
via any available network, including the internet.
In some embodiments, on a first level, assignment of waste items
to waste categories can be performed simply by sorting the items
according to known characteristics. In some embodiments, a waste
sorting algorithm simply involves locating a waste item identifier
in a look-up table or database which lists known identifiers correlated
to respective waste categories, such as the category database described
above. Thus, to the extent that an item can be assigned to a waste
category based solely on one or more waste item identifiers, the
sorting algorithm can comprise a simple look-up routine. If needed,
the sorting algorithm may also seek additional information such
as from the ingredient database described above, or any other available
source of additional information.
Cases may arise where a single waste item possesses two or more
waste identifiers (such as ingredients) belonging to two or more
different waste categories. Thus, in the event that a particular
waste item can reasonably be assigned to two or more waste categories,
yet is only physically capable of being placed in a single container,
the waste sorting algorithm can be configured to assign the item
to a single category by reviewing a number of secondary variables.
Such secondary variables may include a dosage or quantity of specific
ingredients; a dilution or concentration level of one or more ingredients;
a relative hazardousness level of one or more specific ingredients;
a relative reactiveness of one or more ingredients; a shape, size,
type or other feature of a waste item container (e.g., a pill bottle,
syringe, etc); a physical property of the item (e.g., liquid, solid
or gas), or any other datum that may be available to a user, but
that might not be automatically determinable by the sorting station.
If such a piece of additional information is needed in order to
complete an assignment of an item to a container, the sorting station
can prompt a user to input further information. Such additional
information can be input by selecting from multiple answer choices
or by typing.
FIG. 24 is a flow chart illustrating one embodiment of a sorting
algorithm. In the illustrated embodiment, a user initiates the process
by presenting 300 a waste item to be identified by the sorting station.
The sorting station then detects 302 a waste item identifier in
any manner discussed above, such as scanning a barcode, reading
an RFID tag, or scanning a textual or graphic label. The system
then searches 304 the category database using any information or
identifier determined from the item in an attempt to discover whether
the determined identifier has previously been correlated to a waste
category. If the identifier is found 306 to have been correlated
to a waste category, the system continues by assigning the item
to the appropriate waste category, and facilitating disposal of
the item in the appropriate container.
On the other hand, if the identifier is not found in the category
database (e.g., if the system discovers that the determined waste
item identifier is insufficient to determine an appropriate waste
category), the system may search an ingredient database 308 for
additional information or further details about the item. If additional
information is found 320 in an ingredient database, the additional
information, along with the originally-detected waste item identifier
can be used to again search the category database 322. If this information
is found to be sufficient 324 to assign the item to a waste category,
then the system assigns the item 326 to that category, determines
an appropriate container 328 and facilitates disposal 330 of the
item in a container associated with the assigned category. The system
can also store 340 the identifier/category assignment combination
in the category database for use in accelerating the sorting of
future waste items with the same identifier.
However, if the search of the ingredient database yields insufficient
information to assign the item to a waste category, the system may
seek additional information by prompting a user 342 to input additional
information. Such a prompt may request specific information, such
as a choice between known alternatives, or may be more general in
nature. The information received 344 from the user can then be combined
with previously-obtained information about the item, and the category
database can again be searched in an attempt to assign the item
to a category. If this information, in combination with the previously-obtained
information, is sufficient to assign the item to a waste category
346, then the system assigns the item 326 and facilitates disposal
330 of the item in the appropriate container. As above, the system
can also store 340 the identifier/category assignment combination
in the category database for use in accelerating the sorting of
future waste items with the same identifier.
If the information received 344 from the user is insufficient 346
for the system to make a category assignment, the system can either
prompt the user for still more information 342, or the system can
simply assign 350 the item to the most conservative waste category
for disposal of the item as hazardous waste.
FIG. 25 illustrates one embodiment of a portion of a sorting algorithm
which can be used in determining the best container for a particular
item. Once the sorting algorithm has assigned an item to a waste
category, the system determines 328 the container type associated
with the assigned waste category. In the illustrated embodiment,
the station searches the stock of the containers currently loaded
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