Apparatus for storing and sterilizing bio-hazardous waste

A fluid tight waste materials receptacle is located within a housing which has an upper access opening through which infectious wastes from medical clinics or the like may be deposited in the receptacle. A lower access opening enables entry and withdrawal of a sterilized waste receiver which may, for example, be a wheeled cart. The receptacle has an open end and a closed end and is pivotable between a first orientation at which the open end is coincident with the upper access opening in order to receive wastes and a second orientation at which the open end is turned downward to discharge wastes into the receiver. A closure pivoted to the housing seats in and seals the open end of the receptacle when it is at the first orientation. The receptacle is periodically evacuated and steam is admitted to sterilize the contents prior to discharge into the receiver.

TECHNICAL FIELD 
This invention relates to apparatus for processing bio-hazardous or 
infectious waste materials and more particularly to apparatus of this kind 
in which accumulations of such wastes are sterilized prior to disposal of 
the material at a landfill or the like. 
BACKGROUND OF THE INVENTION 
Hospitals, medical clinics and the like generate waste materials which 
require special processing prior to disposal of the material. Used 
bandages, hypodermic needles, specimen containers and tissues, for 
example, may be contaminated with infectious viruses or bacteria. Wastes 
of this kind must be stored in closed containers and be rendered harmless 
prior to disposal at a garbage dump or the like. 
Processing of such wastes by incineration is subject to a number of 
problems. Much of the waste may have a high moisture content and be 
composed of materials which are not readily combustible. Consequently, 
fuel requirements are high and the incinerators are costly to operate. 
Equipment costs and operating costs are further aggravated by the need to 
suppress release of pollutants into the surrounding environment. 
Prior U.S. Pat. Nos. 4,374,491 and 5,084,250 disclose a more economical 
alternative type of infectious waste processor. The apparatus of these 
prior patents sterilizes the waste by exposure of the wastes to high 
pressure steam. Fuel costs are relatively low and prevention of pollutant 
release can be more easily accomplished. 
The waste processors described in the above identified prior patents also 
function as a temporary storage for non-hazardous wastes and include 
mechanism for compacting the wastes prior to transport of the material to 
a dump site. These additional functions make the apparatus particularly 
suitable for use at hospitals or the like which generate large amounts of 
infectious wastes. 
The compaction mechanism significantly increases the bulk and cost of the 
apparatus both directly and indirectly as structural complications are 
needed to enable transfer of wastes from the sterilizer to the compactor. 
Small medical clinics which produce relatively small amounts of waste may 
not need the benefits of these complications and may find the cost of the 
apparatus to be a difficult financial burden. Thus there is a need for a 
simplified and more compact waste sterilizer. 
The present invention is directed to overcoming one or more of the problems 
discussed above. 
SUMMARY OF THE INVENTION 
In one aspect, the present invention provides apparatus for sterilizing 
bio-hazardous waste materials which includes a housing having a front face 
with an upper access opening for enabling entry of waste materials. A 
lower access opening enables entry and withdrawal of a removable 
sterilized waste receiver. An unsterilized waste receptacle in the upper 
region of the housing has an open end and a closed end and is pivotable 
about a horizontal pivot axis which extends in parallel relationship with 
the front face of the housing. The receptacle is pivotable between a first 
orientation at which the open end is in register with the upper access 
opening of the housing and an upended orientation at which the open end is 
below the closed end and at least partially faces the lower region of the 
housing. A closure is coupled to the housing and means are provided for 
enabling movement of the closure between an open position at which 
unsterilized waste materials may be inserted into the receptacle through 
the upper access opening when the receptacle is at its first orientation 
and a closed position at which the closure seats at and closes the open 
end of the receptacle. The apparatus further includes means for 
sterilizing waste materials within the closed receptacle. 
In another aspect of the invention, apparatus for storing and sterilizing 
bio-hazardous wastes includes a housing having a front wall, back wall and 
opposite side members. An upper access opening in the front wall enables 
insertion of wastes which are to be sterilized and a lower access opening 
is proportioned to enable insertion of a sterilized waste receiver and 
withdrawal of the receiver. A fluid tight unsterilized waste receiver in 
the housing has an open end and a closed end. Pivot means enable pivoting 
of the receptacle between a first orientation at which the open end is 
substantially coincident with the upper access opening and a second 
orientation at which the open end faces at least partially in a downward 
direction. The receptacle pivots about an axis of rotation that is 
parallel with the front wall of the housing and the upper access opening. 
A receptacle closure at the front wall of the housing is pivoted to the 
housing and is movable between an open position at which the open end of 
the receptacle is exposed at the upper access opening of the housing and a 
closed position at which the closure seats at the open end and seals the 
receptacle. The apparatus further includes means for sterilizing waste 
material within the receptacle when it is at the first orientation and is 
being sealed by the closure. 
The invention provides a more economical installation for processing 
bio-hazardous wastes at medical facilities or the like. Wastes of this 
kind are typically deposited in plastic bags which are initially used as 
liners for waste baskets or the like. The unsterilized waste receptacle of 
the apparatus may be used as a sealed temporary storage for the bagged 
wastes. Periodically the accumulated wastes may be sterilized, without 
further handling, by activating the sterilizing means which may, for 
example, evacuate air from the receptacle and then inject pressurized 
steam. The sterilized wastes may then be dumped into an underlying cart or 
other receiver without manual handling by activating the pivot means which 
turns the receptacle about a transverse axis. The apparatus may be 
relatively compact in comparison with prior waste sterilizers of the 
general type. 
The invention, together with further aspects and advantages thereof, may be 
further understood by reference to the following description of the 
preferred embodiment and by reference to the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring initially to FIGS. 1 and 2 of the drawings in conjunction, a 
bio-hazardous waste processor 11 in accordance with this example of the 
invention has a housing 12 which includes frame members 13 that support a 
front wall 14, rear wall 16, opposite side walls 17 and a top wall 18. The 
housing 12 of this embodiment has an open underside. 
Front wall 14 is of less length in the vertical direction than the side 
walls 17 and is situated at the upper region of the housing. A horizontal 
shelf 19 extends outward from the lower edge of front wall 14 and the 
portions 21 of side walls 17 which are below the front wall extend outward 
for a similar distance. The forward edges of shelf 19 and the forward 
edges of side wall portions 21 jointly define a lower access opening 22 at 
the front of housing 12. The opening 22 is proportioned to enable entry 
and withdrawal of a sterilized waste receiver 23 which is preferably a 
wheeled cart. Opening 22 may be provided with a latchable door 24, 
fastened to one of the side walls 17 by a hinge 26, although this is not 
essential in all cases as the contents of receiver 23 have been sterilized 
and rendered non-infectious. 
Wastes which are to be sterilized are deposited in a fluid tight receptacle 
27 which is within the upper region of housing 12. The receptacle 27 has 
an open front end 28 and a closed back end 29 and a cylindrical side wall 
31 in this example although the receptacle may have other configurations. 
Referring now to FIGS. 3 and 4, the receptacle 27 may be pivoted between a 
first orientation at which the open end extends vertically and is adjacent 
to the inside surface of housing front wall 14 and an upended position at 
which the open end 28 is below the closed end 29 and faces at least 
partially in a downward direction in order to dump the contents of the 
receptacle into receiver 23. For this purpose, the receptacle 27 is 
supported by pivot couplings 32 formed by a pair of aligned axles 33 which 
extend outward from opposite sides of the receptacle 27 to bearings 34 
which are secured to horizontally extending frame members 13a at opposite 
sides of the housing 12. Curved plates 36 are welded to the side wall 31 
of receptacle 27 to reinforce the side wall and triangular gussets 37 
extend between plates 36 and the axles 33 to further strengthen the 
construction. 
Pivot couplings 32 are located to provide an axis of rotation which 
intersects the receptacle 27 at a location which is between the ends 28 
and 29 and between the portions of the receptacle side wall 31 that are 
uppermost and lowermost when the receptacle is at the first or horizontal 
orientation. Preferably, the pivot couplings 32 are at a substantially 
centered location on the receptacle side wall 31. This minimizes the 
amount of clearance space that must be provided within housing 12 to 
accommodate to the pivoting of the receptacle and also enables pivoting of 
the receptacle with a minimal amount of force. 
Linkage can be provided to enable manual pivoting of receptacle 27 between 
the two orientations of the receptacle but it is preferable to motorize 
the operation. In this example a hydraulic ram 39 is used for the purpose. 
The head end 41 of the ram is pivoted to a bracket 42 which is behind the 
receptacle and which is secured to housing frame member 13a. The 
extensible and retractable rod 43 of the ram 39 extends forward and upward 
along the side wall 31 of the receptacle 27 and is pivotably coupled to a 
pin 44 which extends outward from the side wall at a location that is 
higher than the axis of rotation about which the receptacle pivots. Ram 39 
positions receptacle 27 at its first or horizontal orientation when the 
ram is fully contracted and at its second or waste dumping orientation 
when the ram is fully extended. 
The hydraulic ram 24 of this embodiment of the invention may be replaced 
with other means for pivoting receptacle 27, such as an electrically 
powered actuator for example. 
Referring jointly to FIGS. 1 and 4, access to waste receptacle 27 is 
provided for by an upper access opening 46 situated in the front wall 14 
of housing 11. Opening 46 has a configuration, circular in this example, 
that conforms with the configuration of the open end 28 of receptacle 27 
and is of similar size. Thus the opening 46 and the open end 28 of 
receptacle 27 are substantially coextensive when the receptacle is at its 
first or horizontal orientation. 
A closure 47 seats in the open end 28 of receptacle 27 except at times when 
infectious material is being deposited in the receptacle or when 
sterilized wastes are being dumped into receiver 23. Closure 47 is hinged 
to housing 13 by arms 48 which extend from a rotatable vertical post 51 at 
one side of the upper access opening 46. The closure 47 has a circular 
configuration conform-to the open end 28 of receptacle 27 and seats in an 
annular stepped flange 52 which forms the open end of the receptacle. An 
annular seal 53 is carried by the closure 47 and is compressed against 
flange 52 to provide a hermetic or fluid tight sealing of the receptacle. 
The closure 47 may be of any of the known types that are used to provide a 
pressure resistant sealing effect. In this example the closure 47 is a 
door of the form which has radially directed latching arms 54 which can be 
translated and pivoted by turning of an actuator wheel 56 to enter the 
arms into openings 57 in flange 52 and to cause the closure to exert 
pressure against seal 53. The detailed construction of doors of this kind, 
which are extensively used to seal openings in the bulkheads of ships, is 
known to the art. 
Closure 47 may be provided with a lock 58 of the key or combination type to 
prevent unauthorized opening of the infectious waste receptacle 27. 
Referring again to FIGS. 3 and 4, a transverse partition 59 extends between 
housing side walls 17 within the lower region of the housing at a location 
which assures that the sterilized waste receiver 23 is positioned 
correctly to receive material which is dumped from receptacle 27. 
Waste sterilization is effected by heating the contents of receptacle 27. 
This is preferably accomplished by evacuating air from the sealed 
receptacle 27 and then injecting pressurized steam. Evacuation of air 
removes air from the plastic bags in which the wastes are typically 
contained. This shortens processing time as such air can otherwise act as 
a thermal insulator which slows heat transfer to the contents of the bags. 
Referring now to FIG. 5, fluid circuit components for effecting the 
sterilization include a vacuum pump 61 having an inlet which is 
communicated with the interior of receptacle 27 through a flexible hose 62 
and an outlet connected to a vent 63. Vacuum pump 61 in this example is 
driven by an electrical motor 65 which is actuated and deactuated by a 
manually operated switch 64 but such components can take other forms. The 
pump 61 may for example be of the aspirator type which is operated by a 
flow of steam. Cycling of controls such as switch 64 may be automated and 
be under the control of a microprocessor. Steam from a steam source 66 is 
transmitted to the interior of receptacle 27 through a solenoid piloted 
flow control valve 67 and another flexible hose 68 in response to closing 
of another switch 70. Hospitals and the like often have a pre-existing 
source of piped steam to which the flow control valve 67 may be connected. 
If a preexisting supply is not available, a steam generator may be 
installed at a location near the waste processor 11 or internally within 
the waste processor. 
A motor driven pump 69 draws hydraulic fluid from a reservoir 71 and 
provides pressurized fluid for operating the hydraulic ram 39. A ram 
control valve 72 receives the fluid from pump 69 and is communicated with 
the ram 39 through a pair of flexible hoses 73 one of which communicates 
with the head end of the ram and the other of which communicates with the 
rod end of the ram. The control valve 72 of this example of the invention 
is a three position solenoid operated valve which is spring biased to a 
center position at which the flow paths to both ends of the ram are closed 
and thus the ram is immobilized. A pilot solenoid 74a and control switch 
76a enable shifting of valve 72 to a second position at which fluid is 
applied to the head end of ram 39 and drained from the rod end. This 
pivots receptacle 27 downwardly as previously described to dump the 
contents of the receptacle. Closing of another control switch 76b causes 
another pilot solenoid 74b to shift valve 72 to the third position at 
which fluid is transmitted to the rod end of ram 39 and drained from the 
head end. This causes the ram 39 to contract and thereby return receptacle 
27 to its horizontally extending orientation. 
Referring to FIGS. 4 and 5, above described components of the vacuum and 
steam system are situated in a first sub-housing 77 behind partition 59. 
Hydraulic circuit components are in another sub-housing 78. Manual 
controls, such as switches 64 and 70, are situated at a control panel 79 
located at front wall 14 of housing 12. 
The flexible vacuum hose 62 and steam hose 68 communicate with the interior 
of receptacle 27 through fittings 81 and 82 respectively which are at the 
underside of the receptacle, the hoses being of sufficient length to 
provide slack for enabling the pivoting movement of the receptacle. 
Referring to FIGS. 1 and 2, a manifold plate 83 having spaced apart 
apertures 84 extends across the bottom region of the receptacle 27. Plate 
83 holds the wastes above any condensed steam or other liquid that may be 
present at the bottom of the receptacle, distributes incoming steam 
throughout the receptacle and prevents blockage of the vacuum and steam 
fittings 81 and 82 by wastes which are contained in the receptacle. 
Referring again to FIGS. 4 and 5, the compact and mechanically 
uncomplicated construction of the waste processor 11 enables easy movement 
or reorientation of the installation if that should be desired. 
Repositioning of the waste processor 11 is facilitated if it is provided 
with ground wheels 86 of which one pair are preferably caster wheels. 
In operation, the receptacle 27 with its closure door 47 provides a sealed 
fluid tight storage area for successive batches of infectious waste. 
Periodically the accumulated wastes are sterilized by activating vacuum 
pump 61 to withdraw air from the receptacle and then opening valve 67 to 
admit pressurized steam to the receptacle. Vacuum pump 61 may be operated 
at a reduced rate while steam is being admitted to the receptacle 27 to 
remove cooled and/or condensed steam. Steam exposure times of one half 
hour or more are typically required to effect complete sterilization. 
At the end of the sterilization cycle, the inflow of steam is stopped by 
closing valve 67. The contents of receptacle 27 may be allowed to cool or 
vacuum pump 61 may be operated for a period to remove steam and reduce 
pressure in the receptacle. Closure door 47 is then opened and swung away 
from the open end 28 of the receptacle. Ram control valve 72 is operated 
to cause extension of ram 39. This pivots the open end 28 downward in the 
previously described manner and dumps the sterilized wastes into receiver 
cart 23. A subsequent contraction of ram 39 restores the receptacle to the 
waste receiving orientation. Receiver cart 23 is then withdrawn from the 
waste processor 11 and is either emptied into a garbage dumpster or the 
like and returned or, alternately, used as a temporary storage for 
sterilized waste in which case another similar receiver cart is entered 
into the waste processor. 
Thus the invention provides for safe and efficient storage and 
sterilization of infectious wastes in an installation which is compact, 
mechanically simple and of an economical construction. While the invention 
has been described with respect to a single embodiment for purposes of 
example, many modifications and variations of the construction are 
possible and it is not intended to limit the invention except as defined 
in the following claims.