U.S. patent application number 11/364649 was filed with the patent office on 2006-07-20 for method for processing infectious waste and system for the same.
Invention is credited to Donald L. Smith.
Application Number | 20060159584 11/364649 |
Document ID | / |
Family ID | 36190825 |
Filed Date | 2006-07-20 |
United States Patent
Application |
20060159584 |
Kind Code |
A1 |
Smith; Donald L. |
July 20, 2006 |
Method for processing infectious waste and system for the same
Abstract
A processor and method for treating infectious waste utilizes a
processing chamber having an inlet for delivering processing water
at an elevated temperature and under pressure into the processing
chamber, an opening in the processing chamber for receiving of
infectious waste and for removing treated waste, an agitator for
opening the waste material to the action of the water at elevated
temperature and pressure. A basket and/or a sieve may be carried in
the processing chamber to facilitate drainage of spent processing
water, and an apparatus may be included for removing neutralized
waste through the opening in the processing chamber either by
inverting the processor or by removing and inverting the basket
and/or sieve.
Inventors: |
Smith; Donald L.;
(Greenville, SC) |
Correspondence
Address: |
DORITY & MANNING, P.A.
POST OFFICE BOX 1449
GREENVILLE
SC
29602-1449
US
|
Family ID: |
36190825 |
Appl. No.: |
11/364649 |
Filed: |
February 28, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10981138 |
Nov 4, 2004 |
7032322 |
|
|
11364649 |
Feb 28, 2006 |
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Current U.S.
Class: |
422/26 |
Current CPC
Class: |
F16J 13/06 20130101;
B09B 3/0075 20130101; A61L 11/00 20130101 |
Class at
Publication: |
422/026 |
International
Class: |
A61L 2/08 20060101
A61L002/08 |
Claims
1-55. (canceled)
56. A centrifugal agitator for use in a processing chamber that
processes infectious waste, said agitator comprising: a rotatable
internal shaft having a first end and a second end with an axis
that extends vertically therethrough; a rotatable blade carrier
mounted on said first end of said shaft, said blade carrier having
a surface tapering inwardly toward a free end of said blade
carrier; a plurality of blades pivotally connectable to said
tapered blade carrier, said blades spaced about said free end of
said blade carrier; springs carried by said blade carrier and in
communication with said blades and said blade carrier, said springs
biasing the blades upward about parallel to said axis of said
internal shaft when said blades are in a resting position; and said
blades are being extendable upon rotation of said shaft to outward
positions from said blade carrier about said pivot points as
measured from said axis of said internal shaft due to centrifugal
force.
57. An agitator as in claim 56, wherein, during operation, said
springs permitting said blades to sling waste that wraps around
said tapered blade carrier off of said tapered blade carrier and
said blades, said wrapped waste is forced upward moving said blades
upwardly overcoming said centrifugal force normally biasing said
blades into said outward positions, causing said blades to sling
off said waste, said blades returning to said outward positions
after being freed of said waste.
58. An agitator as in claim 57, wherein said blades taper from
first ends of said blades that are connectable to said blade
carrier to second free ends of said blades which are extendable out
from said blade carrier.
59. An agitator as in claim 58, wherein, when said blades are fully
extended, said blades tilt upward towards said second free ends of
said blades so that said second free ends of said blades are higher
than said first ends of said blades pivotally connected to said
blade carrier.
60. An agitator as in claim 56, further comprising a stationary
agitator housing covering said internal shaft and interacting with
said blade carrier.
61. An agitator as in claim 60, wherein a seal is disposed between
said internal shaft and said agitator housing.
62. An agitator as in claim 56, wherein said second end of said
internal shaft is connected to a drive unit.
63. An agitator as in claim 62, wherein said drive unit creates
centrifugal force that causes said blades to extend in said outward
position as said drive unit spins said shaft, said blade carrier,
and said blades.
64. An apparatus for processing infectious waste, said apparatus
comprising: a processing chamber for receiving infectious waste and
processing water with said processing water being at an elevated
temperature sufficient to process said infectious waste, said
processing chamber forming an opening through which to receive and
remove said waste; a closure member carried adjacent to said
processing chamber, said closure member positionable over said
opening formed in said processing chamber so as to seal the
processing chamber closed and removable from said opening of said
processing chamber to permit receipt of said waste and removal of
said waste after said waste has been neutralized; an agitator
extending within said processing chamber said agitator having a
rotatable internal shaft possessing an axis extending vertically
through said process chamber with a tapered blade carrier disposed
on a free end of said shaft; and a plurality of blades pivoted
about pivot points on said tapered blade carrier, said blades being
spring loaded and being biased upward parallel to said axis of the
internal shaft at rest and, upon rotation of said shaft,
centrifugal force causes said blades to extend outward from said
blade carrier about said pivot points into an angular position as
measured from said axis of said internal shaft.
65. An apparatus as in claim 64, further comprising a sieve
apparatus positioned in said processing chamber containing said
waste while within said processing chamber and facilitating
drainage of said processing water.
66. An apparatus of claim 65, wherein said sieve apparatus further
comprises a removable basket constructed to be received by said
processing chamber.
67. An apparatus of claim 64, wherein said closure member is
latchable into position by means of at least two latch arms that
pull said closure member down tight onto a sealing member located
on the lid.
68. An apparatus of claim 64, further comprising a removal
apparatus in communication with said processing chamber, said
removal apparatus facilitating the unloading of said waste from
said processing chamber.
69. An apparatus as in claim 68, wherein said removal apparatus
also facilitates the loading of said processing chamber with said
waste.
70. An apparatus as in claim 68, wherein said removal apparatus
comprises a hoist.
71. An apparatus as in claim 68, wherein said removal apparatus
comprises a rotation unit operably connected to said processing
chamber, said rotation unit rotating said processing chamber about
an axis.
72. An apparatus as in claim 64, wherein a plurality of torsion
springs operably connects said blades to said blade carrier to
permit said blades to sling said waste that wraps around said
tapered blade carrier off of said tapered blade carrier and said
blades, said wrapped waste is forced upward where said waste moves
said blades upwardly overcoming said centrifugal force normally
biasing said blades outwardly, causing said blades to forcefully
sling off said waste, said blades returning to their outward
centrifugal forced bias after being freed of said waste.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] This invention relates to a method useful for treating
infectious waste as well as a system and processing apparatuses for
carrying out the method.
BACKGROUND OF THE INVENTION
[0002] Currently, medical and biological waste, generally referred
to herein as "infectious waste," generated in hospitals and other
medical and research related facilities that contain
disease-producing organisms or pathological wastes may be disposed
through several disposal processes such as steam sterilization,
microwave or plasma radiation, or incineration. These processes
often require large expensive equipment and can pose environmental
problems.
[0003] Systems for using hot liquids to sterilize the infectious
waste have also been developed. These systems employ large tanks
wherein a pump for chopping and circulating the waste material
through the system circuit is contained within the system. These
systems required large quantities of fresh liquid that require a
long period of time to heat to the desired processing temperature.
Further, once the liquid is used to process the infectious waste,
the liquid is disposed of. Before the system can be used again, the
user must wait for the next batch of fresh process liquid to heated
to the desired temperature. Such use of large quantities of liquid
is costly not only in the use of the large quantity of liquid, but
also through the large expenditure of energy needed to heat each
batch of the liquid to the desired temperature.
[0004] Another concern with these hot liquid systems is that the
pumps used within the systems are industrial pumps having ridge
blades that pulverize waste. The pumps are prone to clogging by
flexible waste such as tubing and textile waste that wraps around
the blades and are subject to damage by metal objects such as
clamps, scalpel blade holders. Therefore, the pumps must be cleaned
on a regular basis. Due to the construction of the system, these
pumps are hard to access and clean. Further, when the pump
inevitably fails, repair is difficult and dangerous because the
pump and system are clogged with infectious waste. Further, due to
the massive size of these systems it is nearly impossible to remove
the system for off-site repair.
[0005] Therefore, a need exists for a process and system for
treating infectious waste that can increase the efficiency and
safety of treating the waste.
SUMMARY OF THE INVENTION
[0006] The present subject matter recognizes and addresses the
above briefly discussed drawbacks, and others of above-described
processes and systems for treating infectious waste. Accordingly, a
general aspect of the present subject matter is to provide a
process and a system, as well as different components of the
system, that can increase the efficiency and safety of treating
infectious waste. Additional aspects and advantages of the
invention will be set forth in part in the following description,
or may be obvious from the description, or may be learned through
practice of the invention.
[0007] In an exemplary embodiment, a method for processing
infectious waste is provided. Heated water is introduced under
pressure into a processing chamber that contains infectious waste.
The heated water should be at a temperature that biologically
neutralizes the infectious waste. The infectious waste and the
heated water are agitated through the action of an agitator to a
point where the infectious waste is neutralized by the heated
water. The temperature of the water is maintained at a temperature
that biologically neutralizes the infectious waste at least until
such neutralization occurs.
[0008] The water is then forced from the processing chamber by a
pressure differential. During the removal of the water, the water
forced from the processing chamber is strained to keep the waste
material within the processing chamber. As the water is removed, at
least a portion of the water is recycled to be reused in processing
further infectious waste. The neutralized waste is then cooled
within the processing chamber before being removed from the
processing chamber.
[0009] To perform the above-described method, an exemplary
embodiment of a system for processing infectious waste to
neutralize the waste is provided. The system includes a processing
chamber for receiving infectious waste and processing water that is
at an elevated temperature sufficient to process said infectious
waste. The processing chamber defines an opening through which to
receive and remove the waste. A closure member is carried adjacent
to the processing chamber. The closure member is positionable over
the opening defined in the processing chamber so as to seal the
processing chamber closed. Further, the closure member is removable
from the opening of the processing chamber to permit receipt of the
waste before processing and removal of the waste after the waste
has been neutralized.
[0010] A holding tank is connected to the processing chamber. The
holding tank supplies the processing water at the elevated
temperature sufficient to process the infectious waste in the
processing chamber. A filter is disposed between the processing
chamber and the holding tank. The filter cleans the processing
water that exits the processing chamber and supplies at least a
portion of the filtered processing water back to the holding tank
to be reused in the processing chamber. In this manner, water can
be recycled increasing the efficiency of the processing system.
[0011] An exemplary embodiment of an apparatus for use in a system
for processing infectious waste is also provided. The apparatus
includes a processing chamber for receiving infectious waste and
processing water that is at an elevated temperature sufficient to
process the infectious waste. The processing chamber forms an
opening through which to receive and remove the waste. A closure
member is carried adjacent to said processing chamber. The closure
member is positionable over the opening formed in the processing
chamber so as to seal the processing chamber closed. Further, the
closure member is removable from the opening of the processing
chamber to permit receipt of the waste for processing and removal
of the waste after said waste has been neutralized.
[0012] An agitator extends within the processing chamber. The
agitator has a rotatable internal shaft possessing an axis
extending through the process chamber with a tapered blade carrier
disposed on a free end of the shaft. A plurality of blades are
pivoted about pivot points on the tapered blade carrier. The blades
are spring-loaded and are biased upward parallel to the axis of the
internal shaft at rest. Upon rotation of the shaft, centrifugal
force causes the blades to extend outward from the blade carrier
about the pivot points into an angular position as measured from
the axis of the internal shaft. The agitator spins the blades
within the processing chamber when the processing chamber is filled
with heated water and infectious waste, thereby mixing the heated
water and infectious waste thoroughly to biologically neutralize
the infectious waste by rapidly exposing the waste to the heat in
the water.
[0013] An exemplary embodiment of a pressure sealable chamber
closure member which is usable in the processing apparatus includes
a lid with a rotatable hub located on the lid. A plurality of latch
arms is connected to the hub on first ends of the latch arms. The
hub is rotatable in a first direction so that the latch arms rotate
causing a second end of each of the latch arms to latch the lid
onto the processing chamber. When the hub is rotated in a second
direction, the latch arms rotate causing the second end of each of
the latch arms to unlatch the lid from the processing chamber.
[0014] Within the processing chamber, an exemplary embodiment of a
centrifugal agitator may include a rotatable internal shaft having
a first end and a second end with an axis that extends vertically
therethrough. A rotatable blade carrier is mounted on the first end
of the shaft. The blade carrier has a surface tapering inwardly
toward a free end of the blade carrier.
[0015] A plurality of blades is pivotally connectable to the
tapered blade carrier with the blades being spaced about the free
end of the blade carrier. Springs are carried by the blade carrier
and in communication with the blades and the blade carrier. The
springs bias the blades upward about parallel to the axis of the
internal shaft when the blades are in a resting position. The
blades are then extendable upon rotation of the shaft to outward
positions from the blade carrier about the pivot points as measured
from the axis of the internal shaft due to centrifugal force. In
this manner, the blades can interact with the processing water and
waste without becoming immobilized by the waste.
[0016] All the features of the subject matter will be described in
greater detail through the use of the appended figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] A full and enabling disclosure of the present invention,
including the best mode thereof, to one of ordinary skill in the
art is set forth more particularly in the remainder of the
specification, including reference to the accompanying figures, in
which:
[0018] FIG. 1 is a schematic view illustrating an exemplary
embodiment of a system for processing infectious waste in
accordance with the present invention;
[0019] FIG. 2 is a front perspective view illustrating an exemplary
embodiment of an apparatus for processing infectious waste
constructed in accordance with the present invention;
[0020] FIG. 3 is a cross-sectional view of the processing chamber
shown in FIG. 2;
[0021] FIG. 4 is a cross-sectional view illustrating a further
exemplary embodiment of a processing chamber in accordance with the
present invention;
[0022] FIG. 5 is a cross-sectional view illustrating an exemplary
embodiment of an agitator in accordance with the present
invention;
[0023] FIG. 6 is a top view illustrating a portion of a sieve in
accordance with the present invention;
[0024] FIG. 6A is a cross-sectional view along lines I of the
portion of the sieve as shown in FIG. 6;
[0025] FIG. 7A is an elevation view illustrating an exemplary
embodiment of a chamber closure member in accordance with the
present invention;
[0026] FIG. 7B is a magnified view of section II of the chamber
closure member of FIG. 7;
[0027] FIG. 8A is a top view illustrating a hub and connecting arm
of the chamber closure member of FIG. 7;
[0028] FIG. 8B is a cross-sectional view illustrating the hub and
connecting arm of FIG. 8A;
[0029] FIG. 9A is a top view of the chamber closure member of FIG.
7 with the latch arms in a closed position;
[0030] FIG. 9B is a top view of the chamber closure member of FIG.
7 with the latch arms in an opened position;
[0031] FIG. 10 is a schematic side view illustrating an exemplary
embodiment of a processing chamber and removal apparatus in
accordance with the present invention;
[0032] FIG. 11A is a schematic side view illustrating another
exemplary embodiment of a processing chamber and removal apparatus
in accordance with the present invention; and
[0033] FIG. 11B is another schematic side view illustrating the
processing chamber and removal apparatus shown in FIG. 11A.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0034] Reference will now be made in detail to the presently
preferred embodiments of the invention, one or more examples of
which are shown in the figures. Each example is provided to explain
the invention, and not as a limitation of the invention. In fact,
features illustrated or described as part of one embodiment can be
used with another embodiment to yield still a further embodiment.
It is intended that the present invention cover such modifications
and variations.
[0035] FIG. 1 illustrates a system, generally 10, for processing
infectious waste to biologically neutralize the waste so that the
waste may be safely discarded or recycled. The system 10 includes a
processing chamber 20, a holding tank 30, a filter 40, a transfer
tank 50 and a heat exchanger 60 that are used to neutralize
infectious waste using superheated water, while recycling at least
a portion of the water to be reused again in the process. Thereby,
efficiency of the processing of infectious waste can be increased
and a savings in cost can be realized through the recycling of the
heated water.
[0036] In general, the infectious waste is placed into the
processing chamber 20 and a closure member 38, such as a lid,
closes the processing chamber 20. The holding tank 30 supplies
superheated process water to the processing chamber 20 to
sterilize, or neutralize, the infectious waste contained therein.
Once the waste has been neutralized, the process water is run
through a filter 40 into a transfer tank 50. At least a portion of
the filtered process water passes through transfer tank 50 and back
into the holding tank 30. The rest of the process water remains in
the transfer tank 50 and is run through the heat exchanger 60 to
transfer heat from the process water to new water being supplied to
the holding tank 30. The holding tank 50 is used to reheat the
process water to a desired temperature for use in processing the
next batch of infectious waste. A control and/or monitoring unit
can be employed to control the system 10.
[0037] Before the system 10 can be used, water has to be introduced
into the holding tank 30. The water can be regular tap water
supplied by a municipality. To initialize the system, a valve 14
opens to allow water from a supply of water 12 to flow through the
heat exchanger 60 and into the holding tank 30. Valve 16 opens to
bypass the flow control valve 18 allowing a faster fill time. A
vent valve 22 on top of the holding tank 30 opens to permit air to
escape the holding tank 30 as the holding tank 30 fills. The size
of the holding tank 30 may vary depending on the amount of waste to
be processed which can be used to determine the amount of water
needed to neutralize the waste and, in turn, designate the size of
the processing chamber 20. For example, the holding tank 30 may be
a 60-gallon tank.
[0038] When the level of water in the holding tank 30 reaches a
first specified amount, a lower level sensor 24 activates a valve
26, causing the valve 26 to open, allowing steam from a supply of
steam 28 to enter a sparge pipe 32, thereby heating the water as it
enters the holding tank 30. For a sixty-gallon holding tank, the
first specified amount at which the lower level sensor 24 activates
the valve 26 may be twenty gallons. Water continues to flow into
the 60-gallon tank until the upper sensor is reached. An upper
level sensor 36 is set at a second specified amount of water. When
the second specified amount of water has filled the holding tank 30
and the upper level sensor 36 is reached, valve 14 and valve 16 are
activated stopping the water flow. For a sixty-gallon holding tank,
the second specified amount of water at which the upper level
sensor activates the valve 14 and 16 to stop the water flow may be
fifty gallons.
[0039] A thermocouple 34 in the holding tank 30 monitors the water
temperature. Valve 26 stays open allowing steam to continue to heat
the water and vent valve 22 on the holding tank 30 stays open until
the water temperature reaches approximately 212.degree. F. for
about a minute. This allows all of the air to escape the holding
tank 30 and the remainder of the holding tank 30 is filled with
steam. Valve 22 then closes and valve J stays open until the water
reaches a desired temperature as the pressure in the holding tank
30 builds. Once the temperature reaches the desired level, the
valve 26 closes. Valve 26 will reopen if the temperature falls
below the desired level. The temperature should be high enough to
neutralize the infectious waste. For example, a temperature of
approximately 285.degree. F. will more the adequately suffice.
Steam pressure at 285 degrees F. is approximately 40 psig.
[0040] Once the holding tank 30 is filled to the desired level and
the water is raised to the proper temperature, the processing of
waste can begin. Waste is loaded into the processing chamber 20 and
the closure member 38 is closed. When the closure member 38 on the
processing chamber 20 is closed and locked, valve 42 opens allowing
water to flow from the holding tank 30 into the processing chamber
20. The pressure in the holding tank 30 is greater than the
pressure in the processing chamber 20, so the water flows with a
great deal of force. Valve 52 opens allowing air to escape the
processing chamber 20 as the water flows from the holding tank 30
into the processing chamber 20.
[0041] A flow sensor 54 located at the bottom of the processing
chamber 20 where the water flows into the chamber 20 senses that
the flow of water stops after the second specified amount of water
has entered the processing chamber 20. The flow sensor 54 then
activates valves 42 and 52 causing the valves 42 and 52 to close.
As the water enters the processing chamber 20, it heats the
processing chamber 20 and the waste in the processing chamber 20 by
giving up some of its energy to the chamber 20 and the waste.
[0042] The temperature of the water will drop along with the
pressure within the processing chamber 20. A thermocouple 56
monitors the temperature within the processing chamber 20. If the
temperature drops below a specified level, then valve 58 opens
allowing steam to sparge into the processing chamber 20 Thereby
raising the pressure within the processing chamber 20 and raising
the temperature back up to the desired processing temperature.
[0043] For example, the temperature of the water may drop from
285.degree. F. to approximately 255.degree. F. and the pressure
will drop to approximately 18 psig. If the temperature drops below
255.degree., then valve 58 opens allowing steam to sparge into the
processing chamber raising the temperature back up to the desired
processing temperature of 255.degree. F. to 256.degree. F.
[0044] Shortly after the water has entered the processing chamber
20, an agitator located in the bottom of the processing chamber 20
starts to spin. The agitator causes the superheated process water
to mix with the infectious waste by opening bags in which the
infectious waste is contained and facilitating the exposure of the
waste to the superheated water. The temperature of the water
thereby biologically neutralizes the waste.
[0045] The waste should be exposed to the process water for a
period of time long enough to neutralize the waste. At temperatures
above 255.degree. F., the processing time is approximately 10
minutes. When the necessary time has elapsed, the agitator stops,
and the valves 62 and 64 open. Due to the pressure differential,
the water then flows through the filter 40 and the transfer tank 50
back into the holding tank 60. At this time, the holding tank 60 is
empty and has cooled sufficiently so that the pressure is at or
near zero. The vent valve 22 can be opened to assure zero pressure.
The 18 psig in the processing chamber 20 forces the water back into
the holding tank 30.
[0046] A flow sensor 78 near the bottom of the holding tank 30
senses when the flow of water stops and closes valves 62 and 64. A
portion of the water is retained in the transfer tank 50. A check
valve 66 at the entry of the transfer tank 50 prevents the back
flow of water out of the transfer tank 50. In this manner, only a
part of the original process water is recycled back in the holding
tank 30. For example, when the system uses fifty gallons of process
water, only forty gallons of the original 50 gallons of water is
returned to a 60-gallon holding tank.
[0047] Valve 14 opens allowing water from a supply of water 12 to
flow through the heat exchanger 60 and into the holding tank 30. A
flow control valve 18 controls the flow of water from the supply of
water 12 through the heat exchanger 60. Normally, water from a
municipality will flow at a rate of approximately two gallons per
minute. Therefore, in an embodiment where ten gallons of water
needs to be added to reach fifty gallons in the sixty-gallon tank,
the water will be replenished in five minutes.
[0048] At the same time valve 14 opens, valve 68 also opens
allowing the water in the transfer tank 50 to flow through the
opposite side of the heat exchanger 60. Valve 70 controls the rate
at which this water flows to approximately two gallons per minute
for 5 minutes. The heat exchanger 60 is sized to remove a portion
of the energy from the used water and return it to the fresh water
as it flows into the holding tank 30. At the same time that valves
14 and 68 open, valve 26 opens to permit steam to sparge into the
holding tank 30 in order to bring the water in that holding tank 30
back up to the desired level. In the embodiment using a sixty
gallon holding tank, this process takes approximately 10
minutes.
[0049] Also, when valves 62 and 64 close, valve 74 opens
momentarily to allow water from the supply of water 12 to spray
from the top of the closure member 38 inside the processing chamber
20 in order to cool the waste inside the chamber 20. At the same
time, valve 72 at the base of the processing chamber opens to drain
the water sprayed from valve 74 into the processing chamber 20.
When the waste has been cooled by the spray from the top of the
processing chamber 20, valve 74 closes. The cooling water flows
through valve 72 to drain. When the cooling water has drained and
the waste is cooled, the closure member 38 on the processing
chamber 20 unlocks and the closure member 38 rises to its open
position. At that time, the waste is removed from the processing
chamber 20. After the waste has been removed, the processing
chamber 20 is ready to start the next processing cycle.
[0050] By recycling and reusing the process water, water
consumption is kept to a minimum. Reclaiming a large portion of
energy from the process water that is drained and not recycled
makes for an energy efficient system. At the same time, adding
fresh water with each cycle keeps the process water from becoming
fouled. The entire system 10 can be drained periodically and
refilled to ensure the quality of the process water being used. To
ensure the effectiveness of the filter 40, the filter 40 may be
cleaned periodically by back flushing the filter with a momentary
burst of water by opening valve 76.
[0051] The systems 10 for processing infectious waste constructed
in accordance with the invention are preferably controlled and
monitored by a control system, such as conventional programmable
logic controllers ("PLC"), such as suitable PLC's manufactured by
Allen-Bradley, a division of Rockwell Automation based out of
Milwaukee, Wis., central processing units ("CPU"), microcomputers,
and the like. Through an appropriate set-up of the control system,
the valves, agitators and/or closure members can be monitored and
controlled separately or in communication with one another. Any
conventional suitable control system or systems may be
employed.
[0052] FIGS. 2 through 11 illustrate different exemplary
embodiments of the processing chambers and related components. In
FIGS. 2 and 3, a processing chamber 120 that can be used in the
exemplary system described above is provided for treating
infectious waste. The processing chamber 120 includes walls 124 and
a concave bottom 126. At a top portion of the processing chamber
120, an opening 122 is defined by the walls 124. The opening 122
provides unobstructed access to the processing chamber 120
permitting loading of the infectious waste to be neutralized into
the processing chamber 120.
[0053] The processing chamber 120 has a suitable housing 130 having
a base 134 and access doors 132. The housing 130 provides an
insulative barrier around the processing chamber 120 to prevent
injury to operators due to the temperatures the exterior of
processing chamber 120 can reach. The access doors 132 provide
access to the processing chamber 120 and other various components
to allow activities such as maintenance to be performed. The
housing 130 can be easily disassembled for major overhauls.
[0054] A closure member, or lid, 138 is provided adjacent to the
processing chamber 120 to sealably cover the opening 122 of the
processing chamber 120. The closure member 138 has a cover top 136
disposed thereon to serve as a cover for the housing 130. The cover
top 136 protects the operator from exposure to the temperatures
which the closure member 138 can reach. The closure member 138 have
seals along its rim 135 that hermetically seal the processing
chamber 120 and closure member 138 when the pressure builds in the
processing chamber from the superheated process water.
[0055] As can be seen from the cut away at the bottom of the
housing 130, a line 128 is operably attached to the processing
chamber 120 for providing the heated water from a holding tank in
the system. The line 128 delivers heated water to the processing
chamber 120 and thereafter drains the used water from the
processing chamber 120. An internal shaft 142 of an agitator 140
extends upward through the bottom 126 of the processing chamber
120. The internal shaft 142 can be driven by a drive unit to spin
the agitator 140 to thoroughly mix the process water supplied by
line 126 with the infectious waste, thereby neutralizing the
waste.
[0056] FIG. 3 shows a cross-sectional view of the processing
chamber to better illustrate the relationship of the agitator 140
to the processing chamber 120. The agitator 140 of this exemplary
embodiment is a centrifugal agitator that is located in the bottom
126 of the processing chamber 120 below a water line that the
process water will reach when processing the infectious waste. An
axis 139 of the agitator is in line with the axis of the processing
chamber 120. The agitator 140 has a plurality of blades 150
disposed on a free end 149 of the agitator 140. As the internal
shaft 142 is rotated, the blades 150 are extended by centrifugal
force in a direction F.sub.2 from a resting position 156 to an
extended position 158. The process water within the processing
chamber 120 is stirred up by the rotating agitator blades 150 along
with the waste that has been placed in the processing chamber
120.
[0057] The placement of the agitator within the processing chamber
is not critical, as long as it allows for proper circulation of the
heated water and allows for removal of the waste from the
processing chamber. Further, multiple agitators can be employed
within a processing chamber to increase the circulation of the
waste and heated water in some embodiments.
[0058] As can be seen from FIGS. 3 and 5, the internal shaft 142 of
the agitator 140 extends vertically through the bottom of the
processing chamber 120 and up through a stationary lower agitator
housing 148 and a stationary upper agitator housing 146. The
internal shaft 142 is mounted in ball bearings 143 that permit the
internal shaft 142 to rotate within the upper agitator housing 146
and the lower agitator housing 148. Due to the environment in which
the agitator 140 operates, the internal shaft 142 is protected with
a labyrinth seal 155 and interior seals 157 to prevent fluid from
the processing chamber 120 from leaking into the bearings 143 and
further, from leaking outside the processing chamber 120.
[0059] The internal shaft 142 is connected to a rotating tapered
blade carrier 144. The blades 150 of the agitator 140 are affixed
to the tapered blade carrier 144. The blades 150 are attached to
the tapered blade carrier 144 so that the blades 150 pivot at the
tapered blade carrier 144 about blade pin pivot points 152. The
blades 150 are spring-loaded via torsion springs 154 so that, when
not turning, the blades 150 reside in an upward resting position
156. By having the blades 150 biased upwards in a resting position
when the agitator is at rest, better permits removal of the
neutralized waste from the processing chamber 120.
[0060] The agitator blades 150 and the tapered blade carrier 144
are secured to the internal shaft 142 via a retaining cap 153. The
retaining cap 153 can be secured to the internal shaft 142 by
screwing the cap 153 into the internal shaft 142 and thereby
holding the taper blade carrier 144 to the internal shaft 142 as
shown in the illustrated embodiment. The retaining cap 153 may have
a threaded member 151 that is inserted through an aperture 145 in
the blade carrier 144. The threaded member can then be screwed into
a threaded aperture 141 in the top of the internal shaft 142. It
may be preferable that the retaining cap be screwed into the
threaded aperture 141 in a reverse direction to the direction in
which the internal shaft 142 spins. The retaining cap used in the
agitator 140 may employ some other conventional method to secure
the tapered blade carrier 144 to the internal shaft 142 such as an
adhesive bonding or a mechanical spring latch.
[0061] To rotate the internal shaft 142 and thus the blades 150,
the bottom of the internal shaft 142 is connected to a drive unit.
The drive unit may be any conventionally known drive system. For
example, the dive unit may be a motor that drives a belt and pulley
system. In such an example, the motor may turn a belt that in turn
rotates the internal shaft 142 in a direction F.sub.1 as shown in
FIG. 5. The internal shaft 142 may also be rotated in a direction
counter to direction F.sub.1.
[0062] As the motor spins the internal shaft 142, the tapered blade
carrier 144 also spins, and as the tapered blade carrier spins,
centrifugal force causes the agitator blades 150 to extend to an
outward position 158 into the processing chamber 120. When the
agitator blades 150 are fully extended, they remain tilted upward
at the free ends 159 so that the ends 159 of the agitator blades
150 are higher than the blade pin pivot point 152 on the tapered
blade carrier 144. These outwardly spinning agitator blades 150
cause the water in the processing chamber 120 to churn and bring
the infectious waste contents of the processing chamber 120 into
contact with the spinning blades 150.
[0063] Infectious waste is generally bagged in plastic bags, and as
such, will be put into the processing chamber while still in the
plastic bags. Much of the waste contained in the plastic bags is
plastic tubing, plastic and textile bandages and wound treatment
material and paper products. However, the waste often also contains
syringes, lancets, and other disposable medical instruments or
devices. When these bags come in contact with the spinning agitator
blades 150, the agitator blades 150 rip open the bags and expose
the infectious waste contents of the bags to the superheated
process water in the processing chamber 120. At the same time, the
fast rotating blades 150 strike the plastic tubing, paper products
and plastic and textile wound treatment material, breaking and
tearing this waste into small pieces and strands.
[0064] The dissevered infectious waste comprising the stringy
textile material, plastic tubing and bags torn apart by the blades
150 has a tendency to wrap around the tapered blade carrier 144 and
agitator blades 150. The waste tends just to wrap around the taper
blade carrier 144 and not the stationary upper and agitator
housings 148, 149 due to the rotation of the tapered blade carrier
144. The tapered blade carrier 144 is tapered toward the free end
149. The angle of the taper is such that the pressure generated by
the wrapping of material causes the resultant force to push the
material upward.
[0065] When the wrapping of waste material generates sufficient
force about the tapered blade carrier 144, the wrapped waste
material then pushes upward against the agitator blades 150. Since
the blade pin pivot points 152 of the agitator blades 150 are lower
than the blade ends 159, when the force of the wrapped material
overcomes the centrifugal force that extends the agitator blades
150 into outward positions 158, the agitator blades 150 momentarily
retract by pivoting about the blade pin pivot points 152 toward
resting blade position 156. This momentary retraction causes the
wrapped material to dislodge and sling upward and off of the
agitator blades 150. As soon as the wrapped waste slings off, the
agitator blades 150 again pivot to outward position 158. To
facilitate the dislodging and slinging off of the wrapped material,
the agitator blades 150 are also tapered from their pivot point 152
toward the free ends 159 so that the agitator blades 150 are
smaller at their extreme ends.
[0066] In this manner, the waste being neutralized can be lessened
in volume, while preventing the agitator 140 from being immobilized
or rendered inoperable for its intended duty by the waste being
neutralized. The blades 150 should be sturdy enough to withstand
contact with syringes, lancets or some other hard medical devices
disposed in a bag in the processing chamber 120. The flexibility
provided by spring loading the blades 150 allows for the blades 150
to be deflected upward if a hard piece waste such as a disposable
medical device comes in contact with one of the blades 150. Through
an appropriate set-up of a control system as described above, the
agitator 140 can be monitored and controlled. Any conventional
suitable control system or systems may be employed.
[0067] In an exemplary embodiment, a sieve apparatus may be
provided within the processing chamber to prevent the waste that
has been neutralized from flow with the process water back through
system. As shown in FIG. 3, a sieve apparatus 160 is provided in
the processing chamber 120. The sieve apparatus 160 is a sieve
basket 162. The sieve basket 162 fits inside the processing chamber
120 and is equipped with elastomeric seals 170 to seal the
sieve/processing chamber interface. The seals 170 help to contain
the waste inside the sieve basket 162 and aid in preventing waste
material from exiting the processing chamber 120 through the line
128. The sieve basket 162 is also preferably constructed with an
opening 164 in the bottom 168 of the sieve basket 162 to permit the
agitator 140 to extend through the bottom 168 of the sieve basket
162. The opening 164 has a seal 172 around the edges of the opening
164. The seal 172 interacts with the agitator 140 to prevent waste
from exiting through the opening 164 during processing and when the
process water is being drained through line 128.
[0068] The sieve apparatus 160 in the form of the sieve basket 162
define sieve holes 176 as shown in sieve section 174 in the FIG. 6.
The sieve holes 176 allow the process water to enter through the
sieve apparatus 160 so that infectious waste contained by the sieve
apparatus 160 can be neutralized. Further, the sieve holes 176
permit the process water to drain from the sieve apparatus 160
while containing the waste within the sieve apparatus 160 and the
processing chamber 120.
[0069] Due to the spinning of the agitator blades 150, the
processed waste often includes fibrous waste material from the
shredded waste. It has been found if the sieve holes are too large,
the space that separates the holes catches the fibrous waste
material near the middle of the waste, the ends of the fibrous
waste material pass through the sieve holes and become entangled on
the backside of the sieve apparatus. Once the waste becomes
entangled in this manner, it is very difficult and time consuming
to remove from the sieve apparatus. Once enough fibrous waste
material has entangled in this manner, the flow of water will
almost completely stop, adversely affecting the neutralization
process time.
[0070] It is thus advantageous for the sieve holes 176 to contain
the processed fibrous waste material by allowing process water to
pass through the sieve, while also rendering the portion of any
fibrous material that passes through the sieve holes 176 too short
to become entangled on the backside of the sieve apparatus. This
may be accomplished by having sieve holes 176 with an appropriate
diameter and spaced at an appropriate distance 178. For example,
the sieve holes 176 may have sizes from about 0.020 inch diameter
to about 0.078 inch diameter that are spaced from about 0.040
inches apart to about 0.125 inches apart. In some embodiments, it
may be preferable to have sieve hole sizes of 0.033 inches in
diameter and spaced at distances of 0.055 inches. By employing
sieve holes 176 sized at such diameters and spaced at such
distances 178, fibrous waste material will lie across the inner
surface of the sieve apparatus and will fall away from the sieve
apparatus when the sieve apparatus is emptied.
[0071] The sieve basket 162 possesses loops 166 to aid in the
loading of the waste into the processing chamber 120 and unloading
of the waste from processing chamber 120. In the exemplary
embodiment shown in FIGS. 2 and 3, a removal apparatus 180 is
provided to load and remove the waste from the processing chamber.
The removal apparatus 180 is a hoist 182 having a hooking device
186 that is extendable and retractable from a hoist arm 188. The
hooking device 186 form hooking arms 184 that are insertable into
the loops 166 of the sieve basket 162. Once the hooking arms are
inserted into the loops 166, the sieve basket 162 can be lifted
into or removed from the processing chamber 120. Due to the upward
resting position 156 of the blades 150 of the agitator 140, the
sieve basket 162 can easily be removed and returned to its position
in the processing chamber 220 without interference from the
agitator 140. The hoist arm 188 can be rotated about the hoist
support 189. The hoist 182 can thereby facilitate the insertion and
extraction of the sieve basket 162 before and after processing.
[0072] In this manner, the sieve basket 162 can be loaded with
infectious waste and then can be inserted into the processing
chamber 120, while the sieve basket 162 can then be removed from
the processing chamber 120 for dumping or removal of the
neutralized waste. The loading of the sieve basket 162 can be done
manually or through automation. For example, the sieve basket 162
may be loaded by dumping a container carrying the infectious waste
into the sieve basket 162 while the sieve basket 162 is in the
processing chamber 120 or while it is outside of the processing
chamber 120. After the processing of the waste, the sieve basket
162 can be removed from the processing chamber 120 by the hoist 182
and then automatically dump the neutralized waste onto a conveyor
belt or into a container for disposal by inverting the sieve basket
162. In this manner, operator contact with the contents of the
sieve basket 162 is eliminated. When the sieve basket 162 has been
repositioned in the processing chamber 120, the processing chamber
is ready for the next cycle.
[0073] FIG. 4 shows a further embodiment of a processing chamber
220. This processing chamber 220 has a concave bottom 226
surrounded by walls 224 and employs a different sieve apparatus
260. The processing chamber 220 is equipped with an integral sieve
262 serving as the sieve apparatus 260. The integral sieve 262 is
placed above the concave bottom 226 of the processing chamber 220,
and is equipped with elastomeric seals 270 to seal the
sieve/processing chamber interface. The exemplary integral sieve
262, as with the sieve basket described above, is constructed with
an opening 264 to permit the agitator 140 to extend through the
integral sieve 262. The opening 264 has a seal 272 around the edges
of the opening 264. The seal 272 interacts with the agitator 140 to
prevent waste from exiting through the opening 264 during
processing and when the process water is being drained through line
228.
[0074] The purpose of the integral sieve 262 is the same as the
sieve basket 162. The integral sieve 262 allows the process water
to drain out of the processing chamber 220 while keeping the
neutralized solid waste products in the processing chamber 220.
However, the processing chamber 220 is unloaded in a different
manner. Instead of removing the waste by removing the sieve
apparatus 260, the sieve apparatus 260 remains in place while
processing chamber 220 can be tilted or inverted along an axis to
dump the waste contents out through the opening 222 into a desired
container or onto a conveyor system to dispose of the waste.
[0075] A different removal apparatuses may be used to invert
processing chambers, like processing chamber 220. The removal
apparatus used to invert the processing chamber may be a manual
apparatus or an automated apparatus. The removal apparatus may also
incorporate a mechanism to aid in loading the processing
chamber.
[0076] For example, in the exemplary embodiment shown in FIG. 7, a
processing chamber 320 that can be manually inverted is
schematically illustrated. Such a processing chamber would be a
small processing chamber used in doctor offices, clinics, or other
places where a minimal amount of medical/bio waste is created on a
daily basis. The processing chamber 320 is attached to a removal
apparatus 380. The removal apparatus 380 in the form of a rotation
unit 382 includes chamber supports 325 on either side of the
processing chamber 320 with each support 325 having an aperture
through which a rotating member 332. The rotating members 332 are
secured to the processing chamber 320 and rotate on within the
supports 325 about an axis 386.
[0077] The process water supply line and the steam supply line (not
shown) pass through the rotating member 332 through the use of
rotary couplings as shown in FIG. 1. The pipes that extend outward
from the rotating members 332 on the rotating member side of the
rotary couplings and feed the steam and process water to the
processing chamber 320 rotate with the processing chamber 320. In
this manner, the process water and steam can be fed into the
processing chamber 320 from the bottom, while still permitting the
processing chamber to rotate about the axis 386. At least one
handle 384 is connected to at least one rotating member 332 to
allow rotation of the processing chamber 320 to an inverted
position 320'.
[0078] To process the waste, a closure member 338 is positioned in
an open position 338' and the waste to be treated is placed in the
processing chamber 320 on top of an integral sieve as described
above. The closure member 338 is then placed in a closed position
along a rim 318 of the process chamber 320. The process water and
steam, as needed, pass through the water and steam supply lines
into the processing chamber 320. An agitator as described above
thoroughly mixes the process water and the waste thereby
neutralizing the waste.
[0079] Once the waste in neutralized and the process water is
drained from the processing chamber 320, the closure member is
reopened to the position 338'. The handles 384 can then be used to
rotate the processing chamber 320 into an inverted position 320' to
dump the neutralized waste into a container 330 for disposal. After
the waste is removed from the processing chamber 320 in this
manner, it may be rotated back to the processing position to start
the process again.
[0080] In this manner, a light weight processing chamber which uses
less superheated process water and processes less waste can be
manually loaded and unloaded. A system employing the processing
chamber 380 allows an expensive alternative to larger system which
require mechanical assisted or automated loading and unloading for
institutions that create a limited amount of bio waste. Other
manual features of this smaller machine may include the manual
opening and closing of the closure member 338.
[0081] In a different exemplary embodiment, as shown in FIGS. 11A
and 11B, a processing chamber 420 may be loaded and unloaded
automatically. Such processing chamber 420 can be employed in
larger institutions such as hospitals, which create a large amount
of medical and bio waste on a daily basis. The processing chamber
420 is positioned in and operably connected to a removal apparatus
480. The removal apparatus 480 is an automated rotation unit 482
that mechanically rotates the processing chamber 420 about an axis
486. For example, the rotation unit may employ a hydraulic system
to rotate the processing chamber 420. As with the manual inverting
removal apparatus described above, the process water supply line
and the steam supply line (not shown) are connected to the process
water pipe and steam pipe (not shown) that feed into the processing
chamber 420 by rotary couplings to allow the process water pipe and
steam pipe to rotate with the processing chamber 420.
[0082] To process the waste in the processing chamber 420, a
container, or bin, 450 containing bagged infectious waste is placed
on a scales platform 460 and weighed to determined the amount of
bagged infectious waste to be placed in the processing chamber 420.
Upon the determination of the weight of the waste, a delivery arm
488 lifts the container 450 from the scale platform 460 in front of
the processing chamber 420 and rotates it toward the processing
chamber 420. At the same time or at some point earlier, the
rotation unit 482 rotates the processing chamber from a processing
position to a receiving position 420'. The delivery arm 488 rotates
the container 450 to a dumping position 450' where the waste
contents within the container 450 are dumped into the processing
chamber 420 in the receiving position 420'. To facilitate loading,
a rotation unit 482 is capable of rotating the processing chamber
520 45.degree. to the receiving position 420', and rotating the
container 450 135.degree. to the dumping position 450' to load the
contents of the container 450 into the processing chamber 520.
[0083] Once the delivery arm 488 returns the container 450 back to
the scales platform 460 and the processing chamber 420 is rotated
back to the upright processing position, a closure member 438 is
lowered into a closed position against the process chamber 420. The
process water and steam, as needed, pass through the water and
steam supply lines and pipes into the processing chamber 420. An
agitator 440 is rotated by a drive unit 441 to thoroughly mix the
process water and the waste thereby neutralizing the waste. As with
the process water and steam pipes, the drive unit 441 rotates with
the processing chamber 420 about the axis 486.
[0084] Once the waste in neutralized, the process water is drained
from the processing chamber 420 while an integral sieve as
described above retains the processed waste within the processing
chamber 420. The closure member 438 can then be reopened. The
closure member should be raised far enough above the processing
chamber 420 to allow the rotation unit 482 to rotate the processing
chamber 420 to an ejection position 420''. In this position 420'',
the waste is dumped from the processing chamber 420 onto a conveyor
belt 492 of a conveyor system 490. The conveyor system 490 was
walls 494 to help keep the waste on the conveyor belt. The waste
material is then carried by the conveyor system 490 to an on-site
shredder and/or compactor before being removed from the
facility.
[0085] Through an appropriate set-up of a control system as
described above, the removal apparatus 180, 380, 480 can be
monitored and controlled. Any conventional suitable control system
or systems may be employed.
[0086] The processing chambers are equipped with a chamber closure
members, or tops, that hermetically seal the unobstructed openings
in the processing chambers to allow pressure to build within the
processing chambers without allowing the pressure to escape. These
closure members can be of different construction, depending on the
size and type of processing chambers. Further, different types of
latching systems may be used to secure the closure member to the
processing chamber.
[0087] FIGS. 7, 7B, 8A, 8B, 9A and 9B illustrate an exemplary
embodiment of a closure member 538 which is used to seal the
processing chamber 520. The closure member 538 includes a lid 537
is lowered onto the processing chamber 520 and secured into
position against a chamber flange 518 of the processing chamber 520
by a latching system 525 positioned on the lid 537. In the
exemplary embodiment, the latching system 525 includes a rotatable
multi-fingered hub 530 connected to latch arms 540 by connecting
rods 550. The multi-fingered hub 530 may be rotated in a first
direction to cause the latch arms 540 to secure the closure member
538 to the processing chamber 520 and may be rotated in a second
direction to release the latch arms 540 and the closure member from
the processing chamber 520.
[0088] The multi-fingered hub 530 is centrally located on the lid
537 of the closure member 538. The lid 537 of the closure member
538 has a rim 516 around its lower edge which is contactable with
the chamber flange 518 around the opening at the top of the walls
524 of the processing chamber 520. The rim 516 has mounting
brackets 542 mounted thereto. Each of the latch arms 540 is
pivotally connected to a corresponding mounting bracket 542 by a
pivot pin 545, which is positioned through alignable apertures in
both the mounting brackets and the latch arms 540.
[0089] A connecting rod is run between the multi-fingered hub 538
and each latch arm 540. At one end of the connecting rods 550 as
shown in FIGS. 8A and 8B, the connecting rods 550 each include a
rod body 553, a ball rod end 562 and a rod end 554. Each connecting
rod 550 is attached to the multi-fingered hub 530 by a
corresponding ball rod end 562 with a bolt 563 and nut 561. Each
finger 529 of the multi-fingered hub 530 defines a receiving
aperture 531 through which the bolt 563 of the ball rod end 562
passes. The nut 561 is tightened onto the bolt 563 of the ball rod
end 562 on the opposite side of the finger 529 of the
multi-fingered hub 530. The ball rod end 562 is rotatable about the
bolt 563.
[0090] At the opposing end of the connecting rods 550 as shown
FIGS. 7B, 8A, and 8B, the connecting rods 550 are attached to the
latch arms 540 by a rod ends 554. The rod ends 554 are connected to
a swivel brackets, or clevises, 552 by pins 556 that are secured by
cotter pins 557. The swivel brackets 552 allow the rod ends 554 to
rotate about the pins 556. Each swivel bracket 552 is, in turn,
connected to a corresponding latch arm 540 by a pin 548. The body
553 of each connecting rod 550 has a threaded hole 551, 568 at each
end 558, 566. The rod ends 554 have right-handed threads 555 which
allow the rod ends 554 to be screwable into the threaded holes 551
at the latch end 558 of the body 553 of the connecting rods 550.
Conversely, the ball rod ends 562 have left-handed threads 564,
which allow the ball rod ends 562 to be screwable into the threaded
holes 568 at the hub end 566 of the body 553 of the connecting rods
550. In this manner, the length of the connecting rods 550 can be
adjusted. In particular, by rotating the body 553 in one direction
or the other, the connecting rod 550 may be lengthened or shortened
due to the orientation of the threads 555, 564 on the respective
ball rod end 563 and rod end 554. Other conventional methods and
configurations may also be used to make the lengths of the
connecting rods 550 adjustable.
[0091] Different drive mechanisms can be used to rotate the
multi-fingered hub 525, for example a hydraulic drive system. In
the exemplary embodiment, a hydraulic cylinder 534, which is
operated in a conventional manner by a hydraulic system, is
attached to a support arm 535 to stabilize the cylinder 534. The
piston arm 536 of the cylinder 534 with a cylinder bracket 533 on
its free end is connected to a hub lever 532 by the cylinder
bracket 533. The hub lever 532 is attached to the multi-fingered
hub 530.
[0092] When the piston arm 536 of the cylinder 534 is in a
retracted position as shown in FIGS. 7 and 9A, the closure member
538 is in a closed and sealed position against the chamber flanges
518 of the processing chamber 520. In the closed position, each of
the connecting rods is in an aligned position 550' in line with the
corresponding latch arm 540. The latch arms 540 have been rotated
about the mounting brackets 542 at the axes 544 so that rollers 546
held at the ends of the latch arms 540 distal from the end carrying
the swivel bracket 552 reside under the chamber flange 518 of the
processing chamber 520.
[0093] As the piston arm 536 is extended from the cylinder, the hub
lever 532 rotates the hub 530 about the hub axis 528 in a direction
V.sub.1. The rotating hub 530 pulls the connecting rods 550 in the
direction the hub 530 is rotating. As the connecting rods 550 are
pulled, the swivel brackets 552 pull on the latch arms 540 causing
them to rotate upward about the mounting brackets at the axes 544.
In this manner, the rollers 546 dislodge from under the chamber
flange 518 and the latch arms 540 are raised as shown in FIG. 9B.
The closure member 538 can then be lifted from the processing
chamber 520.
[0094] In the opened position of the closure member 538 as shown in
FIG. 9B, each of the connecting rods are in a slanted position
550'' in line with the corresponding latch arm 540. The latch arms
540 have been rotated about the mounting brackets 542 at the axes
544 so that the end of the latch arms 554 carrying the rollers 546
are extended in an outward position.
[0095] Once the processing chamber 520 is loaded again and it is
ready to be closed, the closure member 538 is placed in a closed
position and the latch system 525 is activated again. As the piston
arm 536 is retracted back into the cylinder 534, the hub lever 532
rotates the hub 530 in a direction V.sub.2. The connecting rods 550
are pushed from the slanting position 550'' to the aligned position
550'. As the connecting rods 550 are pushed, the swivel brackets
552 push the latch arms 540 causing them to rotate downward about
the mounting brackets at the axes 544. In this manner, the rollers
546 roll under the chamber flange 518 and the latch arms 540 are
placed in a closed position as shown in FIGS. 7 and 9A.
[0096] A seal is carried in the closure member 538 that interacts
with the processing chamber 520 to ensure the pressurized closing
of the processing chamber 520. The seal can be designed to increase
its sealing effective as the pressure builds in the processing
chamber 520. In such a manner, the closure member 538 and latching
system 525 can hermetically seal the processing chamber 520.
[0097] The chamber flange 518 may define a slightly raised portion
on the bottom of chamber flange 518. As the rollers 546 on the
latch arms 540 move under the chamber flange 518 on the processing
chamber 520, the rollers 546 travel over the slight raised portion
on the bottom of the chamber flange 58. As pressure builds in the
processing chamber 520, the closure member 538 is pushed upward by
the pressure, which makes it more difficult for the rollers 56 to
travel back over the raised portion on the bottom of the chamber
flange 518. The sealing member that prevents leakage between the
processing chamber 520 and the closure member 538 may be a lip
type, with the lip pointed inward so that as pressure builds in the
processing chamber 520, the pressure on the seal exerts more force
on the chamber flange 518. Such a construction also allows for a
slight upward movement of the closure member 538 without causing a
leak and locks the rollers 546 on the latch arm 540 in place.
[0098] The number of latch arms 540 used in the latch system 525
may vary. However, it is preferable that at least two latch arms
are employed to facilitate sealing of the closure member 538 to the
processing chamber 520.
[0099] The latching system 525 creates an "over-the-center" type
fastening between the closure member 538 and the processing chamber
520. The aligning of the fingers 529 of the hub 530, the connecting
rods 550 and the latch arms 554 when the connecting rods are in the
aligned position 550' in the closed position of the latching system
525 creates a more stable fastening of the closure member 538 to
the processing chamber 520. Simultaneously, the alignment of each
of the latch arms 554 so that the corresponding swivel brackets
552, axes 544 and the rollers 546 are at least proximally in a
straight line also creates a more stable fastening of the closure
member 538 to the processing chamber 520.
[0100] Through an appropriate set-up of a control system as
described above, the closure member 38, 138, 338 438, 538 and/or
latch system 525 can be monitored and controlled. Any conventional
suitable control system or systems may be employed.
[0101] It would be appreciated by those skilled in the art that
various modifications and variations can be made in the present
invention without departing from the scope of the invention. It is
intended that the present invention include such modifications and
variations as come within the scope of the appending claims and
their equivalents.
* * * * *