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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 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. In some embodiments, a detection system for determining
a presence and/or a quantity of waste items within a container is
also provided. In some embodiments, access to discarded waste items
is restricted once the waste items have been placed in a container.
Medical Patent Claims
What is claimed is:
1. A method for sorting a plurality of medical waste items, the
method comprising: providing a plurality of container compartments,
each container compartment configured to receive a removable container;
providing a plurality of removable containers, wherein each of said
removable containers comprises an opening; providing 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 position; providing a handheld waste item
identification device configured to determine a information on a
medical waste item; providing a control system that compares information
obtained from the handheld waste item identification device with
medical waste item classification information contained in a database;
assigning the waste item to at least one medical waste category;
and identifying one of the removable containers based on the medical
waste category; allowing the movable lid of the identified removable
container to move to the open position to permit disposal of said
medical waste item; and locking the movable lid after receipt of
a medical waste item.
2. The method of claim 1, further comprising locking the movable
lid after the container coupled with said lid has reached a pre-set
fill level.
3. The method of claim 1, wherein the handheld waste item identification
device comprises a barcode scanner that scans said medical waste
item.
4. The method of claim 1, further comprising communicating information
from the handheld waste item identification device to said control
system.
5. The method of claim 1, further comprising wirelessly communicating
information from the handheld waste item identification device to
said control system.
6. The method of claim 1, wherein said handheld waste item identification
comprises a display.
7. The method of claim 1, further comprising displaying information
regarding the waste item being discarded.
8. The method of claim 1, wherein said waste item classification
information comprises classification information based on environmental
or drug enforcement regulations.
9. The method of claim 1, wherein said handheld waste item identification
device comprises a manual input system for manually entering information
regarding the waste item.
10. The method of claim 9, wherein said handheld waste item identification
device comprises a manual input system that queries a user for information
as to whether the waste item is a sharps or whether the waste item
is empty.
11. The method of claim 1, wherein at least one of said moveable
lids is configured to be manually closed.
12. The method of claim 1, wherein at least one of said moveable
lids is configured to be automatically closed or locked upon disposal
of the waste item.
13. The method of claim 1, further comprising: sensing disposal
of said waste item into at least one of said containers, automatically
closing or locking the lid associated with said container upon receiving
information based on said sensor.
14. The method of claim 1, further comprising providing at least
one said containers with a machine-readable identification key,
thereby enabling said container to be hot-swapped.
15. The method of claim 1, further comprising restricting access
to the internal contents of at least of said container while said
container is open and still capable of receiving waste.
16. The method of claim 1, wherein at least one of said containers
is reusable.
17. The method of claim 1, wherein at least one of said containers
is configured to contain sharps.
18. The method of claim 1, further comprising configuring said
control system to automatically determine the waste category associated
with at least one of said containers after said container is placed
into said container compartment.
19. The method of claim 1, further comprising configuring said
control system to automatically determine the waste category associated
with at least one of said containers based on a machine readable
key that is located on said container.
20. The method of claim 1, further comprising providing said database,
wherein said database comprises rules and regulations governing
the disposal of pharmaceutical waste.
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 and individuals 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 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.
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, the invention comprises a system and method
for sorting waste using one or more restricted access containers.
In a preferred embodiment, the system and method comprises a plurality
of containers associated with a plurality of waste categories, wherein
at least one of the containers is configured to restrict access
to the internal portion of the container when the container is open.
The system and method may also include a waste item identification
device configured to determine a qualitative parameter of an item
of waste, and a database comprising waste item classification information.
The system and method may also include a control system programmed
to compare the qualitative parameter of the item to information
contained in the database, and assign the item to a waste category.
The system and method (e.g., the control system in one embodiment)
can be further configured to identify at least one of the containers
based on the waste category.
In one embodiment, the container prevents unauthorized personnel
from accessing the waste item once the item has been deposited into
the container, thereby restricting access to the internal contents
of that container.
In one embodiment, at least one of the containers comprises a lid.
In one embodiment, one of the containers comprises a lid. In another
embodiment, all of the containers comprise lids. In yet another
embodiment, some of the containers comprise lids. In a further embodiment,
one lid is used to cover two or more containers. In one embodiment,
the system comprises one or more lids, wherein the lid is formed
integrally with the container.
The lid may comprise a V-shaped cross-section and circular outer
edges. A "V-shaped cross-section" as used herein shall
be given its ordinary meaning and shall also include substantially
V-shaped configurations. In one embodiment, the V-shaped lid comprises
an angle of about 135 degrees. Shapes other than "V" may
also be used. In some embodiments, the angle is greater than 0 degrees
and less than 180 degrees. In one embodiment, the V-shaped lid (or
similar shaped lid, such as a U-shape or L-shape, or T-shape) has
an angle that is about 120, 125, 130, 135, 140, 145, or 150 degrees.
In one embodiment, at least one of the containers comprises a shield.
In one embodiment, the shield acts in concert with the lid to physically
restrict access to the inside of the container. In one embodiment,
the shield cooperatively moves with the lid. In one embodiment,
the shield is positioned at one end of the lid. The shield may be
positioned at the end of the lid, at the center of the lid, or positioned
somewhere in between.
In one embodiment, the system comprises a latch assembly. In one
embodiment, the latch assembly is coupled to the container and/or
the lid. The latch assembly can cause the lid to open and/or close.
In one embodiment, a system and method for sorting waste based
on primary and alternate disposal strategies is disclosed. In a
preferred embodiment, the system and method comprises a plurality
of containers associated with a plurality of waste categories. The
system and method may also comprise a waste item identification
device configured to determine a qualitative parameter of a waste
item. In one embodiment, the system also comprises a database comprising
waste item classification information. The system and method may
also comprise a control system programmed to compare the qualitative
parameter of the waste item to information contained in the database,
assign the waste item to a waste category, determine the preferred
container in which the waste item should be placed based on the
assigned waste category, determine if said preferred container is
capable of accepting the waste item and direct a user to perform
an alternative disposal action if the preferred container is not
capable of accepting the waste item.
In one embodiment, the user is directed to dispose of the waste
item in an alternative waste container. In a further embodiment,
the user is directed to dispose of the waste item in a waste container
located in another room. In yet another embodiment, the user is
directed to dispose of the waste item in a waste container located
on another floor.
In one embodiment, the user is directed to dispose of the waste
item in a bulk container. In a further embodiment, the user does
not have access to the internal contents of the containers.
In one embodiment, a system and method for sorting waste using
a manual input system is disclosed. In one embodiment, the system
and method comprises a plurality of container compartments, with
each container compartment configured to receive a removable container.
The system may also comprise a plurality of removable containers,
wherein each removable container comprises an opening and a movable
lid. In another embodiment, 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 waste categories. In one embodiment, the movable lid is movable
to an open position and/or a covered position. The system may comprise
a manual input system for entering additional information regarding
the waste item. The system and method may also comprise a waste
item identification device configured to read a barcode on an item
of waste. The system and method may further comprise a database
comprising waste item classification information derived from rules
and regulations affecting the disposal of waste item. In yet another
embodiment, a control system configured to compare information obtained
from the barcode to information contained in the database is provided.
The control system may further configured to assign the item to
at least one waste category, to identify at least one of the removable
containers based on the waste category, to allow the movable lid
of the identified removable container to move to the open position
and/or to lock the movable lid in the covered position when the
control system determines that the removable container is full.
In another embodiment, the system comprises a plurality of containers
associated with a plurality of waste categories and a waste item
identification device is configured to determine a qualitative parameter
of an item of waste. The system may also comprise a manual input
system for entering additional information regarding the waste item.
In a further embodiment, the system includes a database comprising
waste item classification information. In one embodiment, the system
may also comprise a control system programmed to compare the qualitative
parameter of the item to information contained in the database,
and assign the item to a waste category based on the manually entered
additional information and the waste item classification information.
In yet another embodiment, the control system may be configured
to identify at least one of the containers based on the waste category.
In one embodiment, the control system is further configured to
notify a user of the assigned waste category. In another embodiment,
the control system is configured to notify a user of the assigned
waste category by indicating an appropriate container into which
the item should be deposited. In one embodiment, the control system
may be configured to indicate the appropriate container by opening
a door. In other embodiments, the control system may be configured
to indicate the appropriate container by illuminating a light. In
yet other embodiments, the control system may be configured to indicate
the appropriate container by both opening a door and illuminating
a light. In one embodiment, the control system may be configured
to indicate the appropriate container by indicating the necessary
information on a fixed and/or handheld display.
In some embodiments, the manual input system comprises a display
and a keyboard having at least one button. In one embodiment, the
keyboard comprises two buttons. In another embodiment, the keyboard
comprises four buttons. In one embodiment, the keyboard is an alphanumeric
keyboard, permitting the user to enter more detailed information.
In one embodiment, the manual input system comprises one or more
soft keys on a display. In one embodiment, the display is a low
cost display. In another embodiment, the manual input system queries
the user for information regarding the waste item. In some embodiments,
the system queries the user visually and/or audibly. In some embodiments,
at least one button and/or soft key includes a graphical description.
In other embodiments, the manually entered additional information
is related to the volume of remaining contents in a waste item.
In yet other embodiments, the manually entered additional information
is whether the waste item is a sharps. In further embodiments, the
manually entered additional information is related to both the volume
of remaining contents in a waste item and whether the waste item
is a sharps. In one embodiment, the system comprises keys, buttons,
or other means to input whether or not the waste is sharps or not
sharps, empty or not empty.
In some embodiments, the waste item identification device is at
least partially available or situated on a handheld electronic device.
In one embodiment, the additional information is manually entered
into a handheld electronic device. In a further embodiment, access
to the internal contents of the containers is restricted.
In one embodiment, a system and method for sorting waste using
different modes of operation is disclosed. In a preferred embodiment,
the system comprises a plurality of container compartments, each
container compartment configured to receive a removable container.
A plurality of removable containers may also be provided, wherein
each removable container comprises an opening and a movable lid.
In one embodiment, the removable containers are configured to be
placed within the container compartments, wherein each removable
container is associated with at least one waste category. In one
embodiment, the movable lid is movable to an open position and/or
a covered position. The system and method may be further configured
to allow a user to select a mode of operation. In one embodiment,
a waste item identification device is configured to read a barcode
on an item of waste. In a further embodiment, a database comprising
waste item classification information derived from rules and regulations
affecting the disposal of waste items is provided. In another embodiment,
a control system is configured to compare information obtained from
the barcode to information contained in the database and to assign
the item to a waste category. In another embodiment, the control
system is further configured to identify one or more removable containers
based on the waste category. In a preferred embodiment, the control
system is also configured to allow the movable lid of the identified
removable container to move to the open position and to lock the
movable lid in the covered position when the control system determines
that the container is full.
In another embodiment, the system comprises a plurality of containers
associated with a plurality of waste categories, and a waste item
identification device configured to determine a qualitative parameter
of an item of waste. In one embodiment, a database comprising waste
item classification information may be provided. In one embodiment
at least one mode of operation may be selected by a user. In another
embodiment, a control system is programmed to compare said qualitative
parameter of the item to information contained in the database and
to assign the item to a waste category according to the selected
mode of operation. In a preferred embodiment, the control system
is further configured to identify at least one of the containers
based on the waste category.
In some embodiments, the mode of operation differentiates between
economic and environmental benefits. In some embodiments, the mode
of operation depends on the accommodation of available waste haulers.
In further embodiments, access to the internal contents of the containers
is restricted.
In one embodiment, a system and method for sorting waste using
at least one authenticated network connection is disclosed. In one
embodiment, the system comprises a plurality of containers associated
with a plurality of waste categories. In one embodiment, a waste
item identification device is configured to determine a qualitative
parameter of an item of waste. In a further embodiment, a database
comprising waste item classification information is provided. In
other embodiments, a control system is programmed to compare the
qualitative parameter of the item to information contained in the
database and to assign the waste item to a waste category. In other
embodiments, the control system is further configured to identify
at least one of the containers based on the waste category. In one
embodiment, at least one network connection is provided, permitting
the control system to communicate with at least one other component
of the system. In a further embodiment, the one or more network
connections are authenticated.
In some embodiments, the one or more network connections comprise
a hardwired connection. In one embodiment, the hardwired connection
comprises an Ethernet connection. In other embodiments, the one
or more network connections comprise a wireless connection. In one
embodiment, the one or more network connections may comprise both
hardwired and wireless connections. In one embodiment, authentication
is accomplished by using the entry of at least one necessary code.
In one preferred embodiment, the necessary code or codes are entered
using one or more flash drives and/or keyboarded devices. In one
embodiment, the keyboarded device is a personal computer. In one
embodiment, the one or more necessary codes is entered using one
or more Ethernet ports. In some preferred embodiments, the one or
more network connections are secured by one or more firewall systems.
In other embodiments, access to the waste items after the waste
item is placed into said container is restricted to authorized personnel.
In one embodiment, a system and method for sorting waste comprising
updated waste information is disclosed. In one embodiment, the system
comprises a plurality of containers associated with a plurality
of waste categories. In one embodiment, a waste item identification
device is configured to determine a qualitative parameter of an
item of waste. In a further embodiment, a database comprising waste
item classification information configured to receive updates to
the information is provided. In yet a further embodiment, a control
system is programmed to compare the qualitative parameter of the
item to information contained in the database and assign the item
to a waste category. The control system may be further configured
to identify at least one of the containers based on the waste category.
In one embodiment, the updates are received in real-time. In one
embodiment, the updates are received from one or more networks.
In a further embodiment, the updates are received at least once
during a pre-determined time period. In some embodiments, the one
or more networks are secured by one or more firewall systems. In
other embodiments, access to the internal contents of the containers
is restricted.
In one embodiment, a system for determining the level of contents
within a container is disclosed. In a preferred embodiment, the
system comprises a plurality of containers, with each of container
associated with at least one waste category. In one embodiment,
waste is placed in the containers based on a determination by a
database that comprises waste classification information. In one
embodiment, the system comprises a bar passing through each container
at approximately the fill level of the container. The system may
also comprise one or more detectors positioned to detect movement
of the bar. In one embodiment, the system further comprises one
or more position indicators attached to the bar. In one embodiment,
movement of the bar is detected by having the one or more detectors
detect movement of one or more position indicators. In some embodiments,
the detector may be an optical detector, a non-optical detector,
a photo-detector, a photo-interruptor, a mechanical sensor, an electrical
sensor or an acoustical sensor.
In some embodiments, each container further comprises a lid which
works in conjunction with the bar of the corresponding container.
In a further embodiment, when it is determined that the container
is not capable of accepting any additional waste items, the lid
operates to exclude further access to that container. In some embodiments,
the position indicator may be situated on the outside of the container.
In other embodiments, the position indicator may be situated on
the inside of the container. In some embodiments, the detector may
be situated on the outside of the container. In other embodiments,
the detector may be situated on the inside of the container. In
a preferred embodiment, the bar is released at intervals to sweep
across the container to determine the level in the container. In
one embodiment, the bar is released every time the lid is opened.
In some embodiments, access to the internal contents of the containers
is restricted.
In some embodiments, the waste identification device comprises
a handheld device. In some embodiments, the waste identification
device may comprise a wireless handheld device that is operable
to open the appropriate container for disposal of the waste item.
In yet other embodiments, the waste identification device comprises
a wireless handheld device that is operable to signal the appropriate
container for disposal of the waste item.
In one embodiment of the invention, a system for sorting a plurality
of waste items is disclosed. In one embodiment, the system comprises
a plurality of containers, with each container associated with at
least one waste category. In a preferred embodiment, a handheld
waste item identification device is configured to determine a qualitative
parameter of an item of waste. In one embodiment, a database comprising
waste item classification information is provided. In a further
embodiment, a control system is configured to compare information
obtained from the handheld waste item identification device to information
contained in the database. In another embodiment, the control system
is further configured to assign the item to at least one waste category.
In yet another embodiment, the control system is further configured
to identify at least one of the containers based on the waste category.
In some embodiments, the handheld waste item identification device
comprises a barcode scanner. In some embodiments, the handheld waste
item identification device is wireless. The wireless handheld waste
item identification device, in some embodiments, communicates wirelessly
using infrared technology, Bluetooth technology, and/or radiofrequency.
In a preferred embodiment, the handheld waste item identification
device displays information regarding the waste item being discarded.
In one embodiment, the information displayed on the handheld device
comprises information regarding the particular waste container in
which the waste item should be placed. In some embodiments, the
handheld device may be capable of determining the user's location
so that the nearest waste container in which the waste item should
be placed may be identified.
In one embodiment, the system comprises a handheld device that
is used to scan the waste item. The system then determines in which
remote container the waste item should be disposed. The handheld
can provide text instructions to the user as to the proper container.
Alternatively, the system can automatically open the proper container
for disposal. After the waste item is disposed, the container can
be manually or automatically shut.
In some embodiments, the waste comprises medical or pharmaceutical
waste. In some embodiments, the waste item classification information
comprises classification information based on local, state, or national
environmental laws or regulations. In other embodiments, the waste
item classification information comprises classification information
based on local, state, or national drug enforcement laws or regulations.
In other embodiments, the waste item classification information
comprises classification information based on a user's customized
requirements. In yet other embodiments, the waste item classification
information comprises classification information based on one or
more different bases, including environmental laws or regulations,
drug enforcement laws or regulations and/or a customized system.
In one embodiment, at least one container comprises at least one
lid that is operable to be manually closed by the user. In some
embodiments, one or more containers comprise a machine-readable
identification key enabling said container to be hot-swapped.
In some embodiments of the invention, a method of sorting waste
is disclosed. In one embodiment, the method comprises receiving
an identifier associated with waste to be disposed. In one embodiment,
the method further comprises retrieving, based on the identifier,
information from a database, wherein the information is derived
from applicable rules regarding disposal of waste items. In one
embodiment, the method also comprises assigning the waste to a disposal
category based on the information retrieved from the database. In
one embodiment, the method further comprises locating a container
associated with the assigned disposal category. In a preferred embodiment,
the method comprises providing access to an opening of the container
while simultaneously restricting access to the interior contents
of that container. In some embodiments, receiving an identifier
associated with waste is accomplished using a handheld device.
In one embodiment, a method of sorting waste is disclosed. In some
embodiments, the method comprises receiving an identifier associated
with waste to be disposed of using a handheld device. In one embodiment,
the method further comprises retrieving, based on the identifier,
information from a database, wherein the information is derived
from applicable rules regarding disposal of waste items. In one
embodiment, the method may also comprise assigning the waste to
a disposal category based on the information retrieved from the
database. In one embodiment, the method may comprise locating a
container associated with the assigned disposal category. In a preferred
embodiment, the method may comprise facilitating disposal of the
waste item into the container associated with the assigned disposal
category. In other embodiments, access to the internal contents
of the container is restricted. In other embodiments, locating a
container associated with the assigned disposal category also takes
into consideration a machine-readable identification key located
on each container that enables the containers to be hot-swapped.
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 container
and portions of an interface with a sorting and disposal station;
FIG. 14 is a perspective view of an alternative embodiment of a
container and portions of an interface with a sorting and disposal
station;
FIG. 15 is a perspective view of an alternative embodiment of a
container;
FIG. 16 is a perspective view of an embodiment of a 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 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 flowchart illustrating one embodiment of a sorting
algorithm for use by embodiments of a medical waste sorting and
disposal system;
FIG. 25 is a flowchart illustrating a container-checking subroutine
for use by embodiments of a medical waste sorting and disposal system;
FIG. 26 is a diagram of one embodiment of machine-readable patterns
for containers;
FIG. 27 is a table of examples of a 2-button action file;
FIG. 28A is a schematic of one embodiment of a 2-button keyboard
and display indicating a first prompt;
FIG. 28B is a schematic of one embodiment of a 2-button keyboard
and display indicating a second prompt;
FIG. 29 is a table of examples of a 4-button action file;
FIG. 30A is a schematic of one embodiment of a switch arrangement
utilizing graphic images;
FIG. 30B is a schematic of one embodiment of a switch arrangement
utilizing graphic images;
FIG. 31 is a flowchart illustrating a decision logic for identifying
and categorizing a particular waste item;
FIG. 32 is an isometric view of one embodiment of the invention,
showing a cart version of a pharmaceutical waste collection and
sorting device;
FIG. 33 is a perspective view of one embodiment of the invention,
showing a wall unit version of a pharmaceutical waste collection
and sorting device.
FIG. 34A is a perspective view of one embodiment of a sorting and
disposal system, shown presenting a waste item near the scanner;
FIG. 34B is a perspective view of one embodiment of a sorting and
disposal system, shown dropping a waste item into a container;
FIG. 34C is a perspective view of one embodiment of a sorting and
disposal system, shown closing the container;
FIG. 35a is a perspective view of one embodiment of a substantially
vertically-oriented sorting and disposal system;
FIG. 35b is a perspective view of one embodiment of a sorting and
disposal system;
FIG. 35c is a perspective view of one embodiment of a sorting and
disposal system, showing a handheld waste identification device;
FIG. 36 is a perspective view of a container with a lid and a bar;
FIG. 37 is side elevation view of a lid and a bar in the closed
position;
FIG. 38 is a perspective view of a lid and a bar in the closed
position;
FIG. 39 is a perspective view of a lid and a bar in the partially
open position;
FIG. 40 is a side elevation view of a lid and a bar in the partially
open position;
FIG. 41 is a perspective view of a lid and a bar in the open position;
FIG. 42 is a side elevation view of a lid and a bar in the open
position;
FIG. 43 is a perspective view of a bar blocked by the container
contents;
FIG. 44 is a side elevation view of a bar blocked by the container
contents;
FIG. 45 is a perspective view of a latch assembly;
FIG. 46 is an elevation view of a latch assembly;
FIG. 47 is a perspective view of a lid and a bar position detectors;
FIG. 48 is an elevation view of a lid and a bar position detectors;
and
FIG. 49 is a schematic of one embodiment of a firewall system used
for data network protection.
FIG. 50 is a schematic of one embodiment of a prescription drug
label that facilitates proper disposal of the item.
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. As used herein, the terms receptacle and container are
broad terms that can be used interchangeably.
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 removable 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.
As used herein, the term "removable" shall be given its
ordinary meaning, and shall include disposable or reusable containers.
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 one or more particular categories or
classifications of pharmaceutical waste. In one embodiment, a single
container is associated with a single waste category. In another
embodiment, a single container is associated with multiple waste
categories.
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), the abbreviated name
of the drug (or mnemonic), or other data associated with a particular
item of waste. For example, a 325 mg dose of aspirin can be identified
by ASPIOT3272. In one embodiment, 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 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
container, which may be removable.
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 for the user to indicate
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 correct
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, if a composite waste item
could be deposited in more than one container, the containers within
a sorting station can be ranked in order from "less" to
"more" desirable in order to facilitate a determination
of which container is the "most appropriate" hazard container
in a given station. A determination of whether a particular container
type (and corresponding waste category or categories) is more or
less appropriate can be determined by a variety of suitable methods.
In some cases, a selection priority can be determined empirically,
while in other embodiments, the choice may be determined by comparing
properties, such as amount of residual content, relative chemical
toxicity, etc. bioactivity, etc., of elements of a particular waste
item.
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 one embodiment,
the system may be equipped with a dedicated container that is exclusively
used for disposing such unrecognized waste items. The subsequent
handling of waste items in such a dedicated container may depend
on regulatory requirements, the facility's personal preferences
or any other relevant consideration.
In another embodiment, 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 an alternate container if the station does not
include a container associated with the assigned category. In one
embodiment, for example, the alternate container is a container
associated with the highest hazardous level will be opened. In another
embodiment, the alternate container is a container associated with
the "next best" disposal category for the waste item.
In one embodiment, the alternate container is located adjacent
to the preferred (or "first choice") container. In another
embodiment, the alternate container is located in a different location
from the preferred container. For example, the alternate container
can be located in a different room or on a different floor. In yet
another embodiment, if an alternate container is unavailable, then
the item may be rejected. In this situation, the user may be instructed
to obtain additional information on disposal.
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 an alternate container if the station does not include a
container associated with the assigned category. In one embodiment,
for example, the alternate container is a container associated with
the highest hazardous level will be opened. In another embodiment,
the alternate container is a container associated with the "next
best" disposal category for the waste item.
In one embodiment, the alternate container is located adjacent
to the preferred (or "first choice") container. In another
embodiment, the alternate container is located in a different location
from the preferred container. For example, the alternate container
can be located in a different room or on a different floor of a
hospital or other institution.
In some embodiments, 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
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 other
embodiments, the system may be configured to alert a user of other
nearby waste containers capable of accepting the waste.
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.
In some embodiments, the waste sorting and disposal system can
be significantly simplified by appropriately labeling of products
that will eventually be disposed as waste. For example, in one embodiment,
a prescription drug label may provide disposal information at the
time the label is generated. For example, the drug vial or other
pharmaceutical product label may indicate in what waste category
the item should be disposed. As illustrated in FIG. 50, in one embodiment,
the label may provide alternative waste categories under which it
should be disposed, depending on whether the item is empty or not
empty and/or whether the items is or is not a sharps. Such waste
categorization information printed on such labels may be obtained
from a waste disposal database as discussed herein.
For example, in one embodiment, an institution may print its own
specific labels that are based on waste categories. In one embodiment,
multiple labels are generated, each with its own simple code (color,
numerals, letters, etc) and affixed to a drug vial. At the time
of disposal, the scanner (which is configured to read these institution
specific codes) is able to associate the waste item with the appropriate
waste container. In one embodiment, a scanner is not needed. Rather,
the user can read the symbol and dispose of the waste accordingly.
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, consistent with a hospital protocol.
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. In other embodiments, the apertures are
designed to selectively occlude and reveal openings or access ports.
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 container 80, which may be removable.
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.
FIG. 11 shows the cart in an unfolded form, so that it may be placed
or mounted against a wall. FIG. 12 shows the cart in a folded form,
and thus suitable for use as a cart.
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.
FIG. 32 shows another embodiment of the invention comprising a
wheeled cart 60g, a display 70 (which in some embodiments may be
a touch-screen display), and a barcode scanner 74. The display 70
and barcode scanner 74 are supported by a post 38 of suitable size
and shape to orient the display 70 and scanner 74 for convenient
access by a user.
According to one embodiment, a user holds a pharmaceutical waste
item to be discarded near the scanner 74 and responds to one or
more questions presented on the display 70. Using a database lookup
and a specialized computer algorithm, a CPU then determines the
proper container to receive the waste item. In other embodiments,
the user simply scans the item to be discarded without answering
any questions or inputting any information into the system.
The cart 60g is equipped with a plurality of lids 82. As shown
in FIG. 32, each lid 82 is latched in a closed position by a release
mechanism 62. When a particular lid 82 is directed to open, electronics,
a solenoid, and a spring (not shown) cause the lid 82 to rotate
to an open position revealing a container (not shown) for receiving
the pharmaceutical waste item. Following manual deposit of the item
into the appropriate container, the user closes the lid 82 by applying
hand pressure to a lever 66, which, in one embodiment, is an extension
of the lid 82. The release mechanisms 62 can be protected by covers
68 to prevent tampering with the release mechanisms 62 contained
therein.
The cart 60g is further provided with a deck 42, side skins 44,
and doors 48 to prevent damage resulting from spills and unauthorized
access of the mechanisms 62, internal components, and the containers.
The doors 48 are provided with a key lock 46 so that only authorized
service personnel may change out the containers when full.
A power entry module 36 provides an electrical cord for connection
to a wall outlet for powering the cart and/or charging an internal
battery (not shown). One of ordinary skill in the art will recognize
that other means for supplying power may also be used.
The cart 60g is also equipped with a base 30, wheels 32, and one
or more handles 34 to enable pushing the cart 60g from one location
to another.
In some embodiments, the invention is provided as a wall unit.
FIG. 33 shows one embodiment comprising a wall unit 60h, a display
70 (which in some embodiments may be a touch-screen display), and
a barcode scanner 74. The display 70 and barcode scanner 74 are
oriented for convenient access by a user.
In one embodiment, a user holds a pharmaceutical waste item to
be discarded near the scanner 74 and responds to some questions
presented on the display 70. Using a database lookup and a specialized
computer algorithm, a CPU then determines the proper container to
receive the waste item. In other embodiments, the user simply scans
the item to be discarded, without answering any questions or imputing
any information into the system.
The wall unit 60h is equipped with a plurality of lids 82 arranged
in an array. As shown in FIG. 33, each lid is latched in a closed
position by a release mechanism 62. When a particular lid 82 is
directed to open, electronics, a solenoid, and a spring (not shown)
cause the lid 82 to rotate to an open position revealing a container
(not shown) for receiving the pharmaceutical waste item. Following
manual deposit of the item into the appropriate container, the user
closes the lid 82 by applying hand pressure to a lever 66, which
in one embodiment is an extension of the lid 82. The release mechanisms
62 can be protected by covers 68 to prevent tampering with the release
mechanisms 62 contained therein.
The wall unit 60h is further provided with a deck 42 (one at each
level in the array), side skins 44, and doors 48 to prevent damage
resulting from spills and unauthorized access of the mechanisms
62, internal components, and the containers. The doors 48 are provided
with a key lock 46 so that only authorized service personnel may
change out the containers when full.
The wall unit 60h, in one embodiment, can include an electrical
connection or other means (not shown) for powering the unit and
mounting brackets (not shown) for anchoring the unit 60h to a wall.
FIGS. 34A, 34B and 34C show an embodiment, which may be provided
in cart form or as a wall unit. In one embodiment, a user holds
a waste item to be discarded near a barcode scanner 74. In one embodiment,
using a database lookup and a specialized computer algorithm, a
CPU determines the proper container to receive the waste item. The
waste item can be discarded into the appropriate container after
the corresponding lid 82 has been opened. Once the waste item has
been discarded, the user may push the lid 82 to its default, closed
position.
FIGS. 35a, 35b, and 35c show alternative embodiments of the waste
collection system. FIG. 35a shows a sorting device that is oriented
in a substantially vertical position. FIG. 35b shows a sorting device
that has a plurality of top and side access regions. As in other
embodiments, using a database lookup and a specialized computer
algorithm, a CPU determines the proper container to receive the
waste item. The waste item can be discarded into the appropriate
container after the corresponding lid has been opened. This embodiment
is advantageous in healthcare facilities where available space is
limited. In some embodiments, the sorting device is further provided
with a deck 42, side skins 44 and doors 48 to prevent damage resulting
from spills and unauthorized access of the mechanisms, internal
components and the containers. In one embodiment, the doors 48 are
provided with a key lock 46 so that only authorized service personnel
may change out the containers 80 when full. In some embodiments,
the sorting device may also be equipped with a base 30, wheels 32
and/or one or more handles 34 to enable pushing the cart from one
location to another. FIG. 35c shows alternative embodiments (for
example, alternatives of FIGS. 32 through 35b) in which the waste
identification device (such as barcode scanner 74) is provided as
or on a handheld 73 or other portable device. The display 70 may
be provided as or on the handheld 73 or other portable device. Handheld
embodiments may be used instead of or in addition to waste identification
devices that are attached or fixed to a sorting station or other
location.
In some embodiments, the container lid or other mechanism that
provides access to the interior of the container, may be configured
to open and close automatically. In other embodiments, for safety
purposes, the container lid or other mechanism that provides access
to the interior of the container, may not be capable of closing
automatically. In such embodiments, the user is required to manually
close the lid or other mechanism.
In a preferred embodiment, as illustrated in FIGS. 34a, 34b and
34c, the sorting system may be configured to automatically open
a container lid following a barcode scan of the waste item. The
user can then manually close the lid after discarding the waste
item in the container. In one embodiment, the container automatically
opens and closes. In another embodiment, the container automatically
opens and can be closed manually. In yet another embodiment, the
container is operable to be manually opened and closed. In a further
embodiment, the container is opened manually, and closes automatically.
Automatic closure of the container can be based on a pre-determined
time interval. Alternatively, once a waste item is disposed within
the container, the container may use one or more sensors to determine
that the waste has been appropriately discarded, and automatically
closes upon this sensor determination. In yet another embodiment,
the user can communicate to the system (e.g., by pressing a button)
to close the container automatically.
Containers
In some embodiments, the 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, 2-gallon, 3-gallon, 5-gallon, 8-gallon, and 13-gallon
sizes. Other sizes can also be used.
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 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
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, 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 chemotherapeutic waste. Color-coded containers
can advantageously simplify the tasks associated with manual transportation
and processing of the containers, and can aid in ensuring 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 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 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 allow 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 (e.g., automatically 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 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.
Level sensors are commonly used in many fields to determine a quantity
of a solid or liquid within a container. Three popular level sensors
include floats, sight glasses and ultrasonic systems.
In a float system, a buoyant device or "float" is placed
in the container, where it remains partially submerged in the liquid
retained within the container. The float is used to detect a level
of a fluid in the container by activating a switch located at a
pre-determined point. Alternatively, the float detects the container's
fluid level by activating a potentiometer, which reports the fluid
level over a calibrated range.
Sight glass type level sensors evolved from manual systems in which
an operator observed the level in a container through a transparent
window. Sight glass type sensors which today are implemented using
light sensors, generally require a window through which to project
and receive light.
Ultrasonic fill level sensors direct a beam of ultrasonic energy
toward an object and detect the time delay associated with that
beam of energy reflecting off the object and returning to the sensor.
Thus, the time delay correlates to a particular height of the contents
in the container.
The assignee of the present application also owns technology related
to the optical detection of the level of material in a translucent
plastic waste container. See, e.g., application Ser. Nos. 10/945,223;
10/946,252; 10/946,161; 10/945,773; 10/946,164; 10/946,207; 10/946,208;
and 10/946,054, herein incorporated by reference. As described below,
in some embodiments, measurements are made by illuminating one side
of the container and collecting the light received by an array of
photo detectors located on the opposite side of the container. In
one embodiment, a microprocessor interprets the light received at
the array of receptors, compensates for ambient light and the relative
transmissivity of individual containers, and determines whether
the container is full.
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 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 be 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 affect 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 affected 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 |