Waste disposal system

• US 4,578,185 A
• Filed: 07/24/1985
• Issued: 03/25/1986
• Est. Priority Date: 07/24/1985
• Status: Expired due to Fees

• Current Assignee: Medical SafeTEC, Inc.
• Original Assignee: Medical SafeTEC, Inc.
• Inventors: Rapp, Jeffrey C., Elliott, Martin E., Wilson, Joseph H., Southern, Brian K.
• Primary Examiner(s): WYSE, THOMAS G
• Application Number:
  US06/758,439
• Time in Patent Office: 244 Days
• Field of Search: 210/143-145, 210/147, 210/148, 210/153, 210/158, 210/160, 210/171, 210/173, 210/174, 210/188, 210/192, 210/202, 210/251, 210/259, 210/297, 210/298, 210/346-401 , 210/138-140, 210/85, 210/87-89, 210/91, 210/92, 210/488-492
• US Class Current: 210/85
• CPC Class Codes: A61L 11/00 Methods specially adapted for refuse disintegrating medical waste B02C19/0075; disposal of medical waste B09B3/00
• CPC Class Codes: B02C 13/04 with beaters hinged to the rotor; Hammer mills
• CPC Class Codes: B02C 19/0075 specially adapted for disintegrating medical waste sterilisation of refuse A61L11/00; disposal of medical waste B09B3/00
• CPC Class Codes: B02C 21/00 Disintegrating plant with or without drying of the material for grain B02C9/04
• CPC Class Codes: B02C 23/18 Adding fluid, other than for crushing or disintegrating by fluid energy for tumbling mills B02C17/186; feeding devices B02C23/02
• CPC Class Codes: B09B 3/0075 Disposal of medical waste casings for used articles, e.g. sharps A61B50/362; sterilisation of refuse A61L11/00; disposal of used needles or syringes A61M5/3205; disintegrating medical waste B02C19/0075
• CPC Class Codes: Y10S 241/606 Medical/surgical waste comminution

Abstract

A waste disposal system for treating and disposing of infectious waste articles in a substantially controlled, closed, aseptic environment and for converting such infectious waste articles into a safely disposable, non-infectious non-toxic residue of solid waste independent from disinfecting liquid waste. A waste delivery conveyor transfers waste articles from an input region to preliminary waste processing apparata for preliminarily fragmenting the waste for further treatment by the system. Disinfectant spray is deposited on the waste as it enters the preliminary waste processing apparatus with the fragments resulting therefrom, together with the disinfectant liquid, being transferred to rotary hammermill elements to convert the fragment disinfectant solution to a solution of fine waste particles and disinfectant solution. Liquid solid particle separator apparata then separates the solid waste particles from the liquid disinfectant for independent evacuation of same. The system further includes vacuum ventilation elements to maintain any released bacteria or particles within the system until completely processed and disinfected with system switching controls serving to operate and sequence operation of the system components relative to one another by computer.

Claims

1. A waste disposal system for treating and disposing of infectious waste articles in a substantially controlled closed aseptic environment and for converting said infectious waste articles into a safely disposable noninfectious and nontoxic residue through the thorough disintegration and disinfection of such articles, said system comprising:

system input means into which accumulated quantities of said waste articles are initially placed for subsequent treatment and disposal of same;

waste delivery means operably connected to said waste input means at a first delivery end for transferring said accumulated quantities of said waste articles to a second delivery end, said second delivery end being positioned substantially opposite said first delivery end;

preliminary waste processing means operably positioned proximate to the second delivery end of said waste delivery means for preliminarily restructuring said waste articles into substantially small waste fragments for further treatment and disposal of same by said waste disposal system;

disinfectant spray means operably positioned adjacent one or more of said second delivery end of said waste delivery means and said preliminary waste processing means for enveloping and impregnating one or more of said waste articles and said waste fragments in a bacteria killing disinfecting liquid solution through the spray emitted by said spray means and the operation of said preliminary waste processing means;

said disinfecting liquid solution and waste fragments being jointly directed from said preliminary waste processing means by fragment-solution channeling means having a first and second end with said first end being operably positioned adjacent said preliminary waste processing means,

rotary hammermill means operably attached to the second end of said fragment-solution channeling means for receiving said waste fragment-disinfectant solution from said fragment solution channeling means, and for violently disintegrating same at a substantially high speed, into a waste particle-disinfectant solution,

said rotary hammermill means being powered by hammermill motor means operably coupled thereto;

hammermill solution transmission means having a first and second end through which said waste particle-disinfectant solution is routed out of said rotary hammermill for further treatment and disposal by said waste disposal system;

liquid-solid particle separation means operably attached to the second end of said hammermill transmission means for separating, on a continuous basis, said disintegrated particles of solid waste from said enveloping and impregnating disinfectant liquid;

said liquid-solid particle separation means including operable connections to liquid evacuation means and solid particle evacuation means for disposal of said disinfectant liquid and said solid waste particles respectively;

system vacuum ventilation means operably associated with said disposal system for effectively precluding the inadvertent release of bacteria and other contamination during the treatment and disposal of said waste articles by said system; and

system switching control means operably associated with one or more of said waste input means, waste delivery means, preliminary waste processing means, disinfectant spray means, rotary hammermill means, liquid-solid particle separation means and system vacuum ventilation means for controlling the activation and sequencing of one or more of same relative to one or more of the others.

2. The waste disposal system of claim 1 in which the invention further comprises disinfectant storage means for containing accumulated quantities of said disinfectant liquid,

said disinfectant storage means being operably connected to said disinfectant spray means for supplying, through disinfectant conduit means, desired amounts of disinfectant liquid for spraying of same onto said waste articles at said position adjacent one or more said second delivery end of said waste delivery means and said preliminary waste processing means.

3. The waste disposal system according to claim 2 in which the invention further comprises disinfectant generation means;

said disinfectant liquid comprising a disinfectant solution of sodiumhypochlorite and water;

said disinfectant generation means comprising an on-site disinfectant generator operably coupled to said disinfectant storage means for creating said sodiumhypochlorite compound through electrolytic treatment of a brine solution,

said generated sodium hypochlorite being combined with water after storage in said disinfectant storage means to form a two tenths (0.2%) percent concentrate solution having a pH of 8.5;

said generated disinfectant, upon combination with said water to form said two tenths (0.2%) percent concentrate solution, being supplied to said spraying means through said disinfectant conduit means.

4. The invention according to claim 1 in which said waste delivery means comprises a substantially inclined motorized conveyor apparatus;

said conveyor apparatus including, at a first end, said system input means for initial placement of said quantities of said waste articles for subsequent treatment and disposal,

said conveyor apparatus further including a substantially flat continuous conveyor belt with laterally positioned bars positioned thereupon for effectively transferring said waste articles to said second delivery end proximate the preliminary waste processing means, as a driving motor operably attached thereto said conveyor apparatus is activated by said system switching control means to transfer said waste articles thereupon.

5. The invention according to claim 4 in which said laterally positioned bars and said conveyor apparatus belt are formed of a substantially elastomeric material,

said elastomeric material being selected from the class of elastomeric materials composed of urethane and rubber.

6. The invention according to claim 4 in which said conveyor apparatus includes one or more draped slitted curtains suspended immediately above said conveyor belt along the longitudinal path of said conveyor belt;

said slitted curtains permitting uninterrupted passage of said accumulated waste articles thereon said conveyor belt as said conveyor belt moves same from said first delivery end to said second delivery end of said waste delivery means;

said conveyor apparatus further including a substantially sealed conveyor housing about said conveyor belt,

said slitted curtains being suspended from the top of said housing and cooperating with said housing to preclude the harboring, backflow and inadvertent release of potential bacteria and backflowing waste particles present in said system at said waste delivery means and for reducing and isolating noise associated with said system.

7. The invention according to claim 6 in which said one or more draped slitted curtains is constructed of a substantially vinyl material to more effectively enable unobstructed passage of said accumulated waste articles on said conveyor belt and to simplify the cleaning of said one or more slitted curtains;

said conveyor apparatus housing enclosure being constructed of a substantially stainless steel material in the form of a chute to preclude the undesired harboring of bacteria in the proximity of said waste delivery means.

8. The invention according to claim 1 in which said system input means includes, at a position proximate to said first delivery end, drain means located at the lowermost region of said conveyor apparatus to enable the draining of rinsing solution used to rinse said system input means and waste delivery means between operations of said waste disposal system so as to drain away accumulations of disinfectant spray, infected and bacteria laden waste particles.

9. The invention according to claim 1 in which said preliminary waste processing means comprises a dual element counter-rotating cutter-shredder apparatus,

each of said dual elements possessing a plurality of three tooth shredding disks which are respectively and sequentially articulated in alternating fashion between one another,

each of said cutting disks of said dual elements cooperating with a series of stationery jogging members operably disposed in sequential fashion within adjacent positions amongst said cutting disks,

said cutter-shredder being powered and driven by cutter-shredder motor means operably attached to each of said counter-rotating dual elements.

10. The invention according to claim 9 in which said preliminary waste processing motor means includes a torque reactive controlled motor which reacts to overloads occurring within the cutter-shredder means by deactivating and stopping said shredder in the event of jamming therewithin.

11. The invention according to claim 9 in which said preliminary waste processing means is operably disposed in a substantially sealed shredder housing immediately surrounding said dual counter-rotating shredding elements;

said shredder housing having attached thereto, at its upper region, a substantially sealed chute element in operable communication with a substantially sealed conveyor apparatus housing formed about said waste delivery means,

said sealed chute element receiving said accumulated waste articles at said second delivery end of said waste delivery means for, in turn, transferring same, through gravity, to the nip formed between said cutting disks among said dual counter-rotating shredder elements in said preliminary waste processing means.

12. The invention according to claim 11 in which said spray means comprises a substantially horizontally positioned spray bar extending the longitudinal length of said dual elements and fixedly restrained thereover, for substantially downward vertical spraying of said disinfectant liquid, from a position along the top of said substantially sealed chute;

said disinfectant spraying means serving to continuously dispense said liquid disinfectant over said accumulated quantities of waste articles as said articles reach said second delivery end, while said accumulated waste articles fall, by gravity, into said shredder-cutter apparatus for preliminary fragmentation thereof;

said liquid disinfectant surrounding and impregnating both the waste articles awaiting fragmentation by said shredder-cutter, as well as the fragments being released therefrom into said fragment-solution channeling means, in turn leading to said rotary hammermill means.

13. The invention according to claim 12 in which said sprayer means dispenses said liquid disinfectant spray at a rate approximating thirty gallons per minute onto said waste articles and said waste article fragments therebelow.

14. The invention according to claim 1 in which said rotary hammermill means comprises a high-speed hammermill apparatus capable of violently disintegrating the waste article fragments immersed and impregnated in said disinfectant liquid solution so as to effectively disintegrate said fragments into substantially small waste particles for improved penetration thereby by said disinfectant liquid to, in turn, enable the complete and substantial disinfection of bacteria carried by same,

said fragment solution channeling means comprising a substantially sealed channel member operably connected in sealed relationship to a sealed preliminary waste processing housing surrounding said preliminary waste processing means, at said first end of said channeling means and in sealed operable connection with a side entry aperture in said rotary hammermill means at the second end of said fragment solution channeling means;

said rotary hammermill means including a substantially sealed hammermill housing through which said hammermill motor means is operably coupled to the hammermill apparatus disposed therewithin,

said entry aperture operably positioned in offset fashion within one side wall of said substantially sealed hammermill housing.

15. The invention according to claim 14 in which said hammermill apparatus further comprises;

a primary rotating member directly and operably connected to said hammermill motor means through hammermill axle means,

a plurality of hammer members operably mounted for pivotal movement about the outer periphery of said primary rotating member;

a plurality of fragment jogging members operably positioned at the upper interior periphery of said hammermill apparatus housing for more effectively disintegrating said waste article fragments during rotation of said primary member and hammer members; and

a plurality of apertures located at and through the bottommost peripheral region of said hammermill housing for release of said waste particle-disinfectant solution after disintegration of same by said rotary hammermill means into the first end of said hammermill transmission means.

16. The invention according to claim 15 in which said release apertures include a plurality of substantially small circular release apertures leading through said hammermill apparatus housing into said first end of said hammermill transmission means;

and

an overload release aperture maintained in a sealed position during normal operation by a releasable covering door operably connected to door positioning means capable of opening said covering door when speed detection means disclose a jamming situation within the hammermill apparatus, thereby expediting the release of accumulated waste particle-disinfectant solution out of said rotary hammermill apparatus and into said hammermill transmission means upon such a jam occurrence,

said speed detection means comprising a rotary speed sensor positioned about said hammermill axle means for detecting an abrupt reduction in speed thereof to, in turn, activate said covering door to immediately open to more rapidly evacuate waste particle-disinfectant solution from the interior of said hammermill apparatus housing;

said door positioning means comprising pneumatic piston means operably affixed at one end to said covering door to operate same upon said occurrence of jamming, maintaining same in a closed position at all other times.

17. The invention according to claim 15 in which said primary rotating member of said hammermill apparatus is suspended for rotation about opposite faces of said hammermill housing by a plurality of hammermill bearing assemblies operably communicating with said primary rotating member through said hammermill axle means;

each of said plurality of hammermill bearing assemblies having means for withstanding contamination from migration of said waste particle-disinfectant solution emanating from within said hammermill housing and along said axle means towards portions of said bearing means, to further preclude corrosion and interference of said migrating particles-solution into said bearing.

18. The invention according to claim 17 in which said means for withstanding contamination in each said bearing assembly comprises;

a plurality of bearing spacer means each providing a cavity immediately adjacent each said bearing assembly, said bearing spacer in direct and operable communication with respective portions of said axle means;

an inlet and outlet fitting positioned in each said bearing spacer means permitting attachment thereto of an incoming and outgoing flushing conduit for operable communication with the interior of said bearing spacer means;

flushing medium pumped through said flushing conduits to enter into and exit from said bearing spacer,

said flushing medium being pumped continuously during the operation of said hammermill apparatus to flush each said bearing spacer to, in turn, clean out said portions of migrating waste particles and disinfectant solution which could otherwise enter and adversely affect said bearing assemblies.

19. The invention according to claim 18 in which said means for withstanding contamination in each said bearing assembly further comprises a slinger element operably and fixedly attached to said axle means within each said bearing spacer means for further assisting, through the creation of centrifugal dispersion, the flushing of said migrating waste particles and disinfectant solution out of said bearing spacer and through and out said exiting flushing conduit.

20. The invention according to claim 17 in which said means for withstanding contamination in each said bearing assembly comprises a continuous greasing apparatus operably and fixedly attached to bearing elements within each said bearing assembly which continuously and effectively circulate fresh greasing medium into and about said bearing elements, to further preclude the inadvertent contamination, corrosion and undesired creation of excess friction about said rotating bearing elements by constantly greasing same, while further flushing out traces of migrating waste particles and disinfectant solution reaching said rotating elements.

21. The invention according to claim 15 in which said rotary hammermill motor means are operably connected to said primary rotating member within the hammermill apparatus housing through quick release coupling apparatus means which automatically releases said motor means from connection with said primary rotating member upon the occurrence of a torque limiting jam;

said torque limiting jam situation being sensed to activate said quick release coupling through torque sensing apparatus operably communicating with the hammermill apparatus,

said quick release coupling disconnecting said motor means from said hammermill apparatus upon the occurrence of a jam and controlling, automatically, the winding down of the otherwise free riding motor means after such disconnection;

said quick release coupling further including warning means for notifying the operator of said waste disposal system of the occurrence of said hammermill motor means disconnection and wind down.

22. The invention according to claim 1 in which said hammermill transmission means comprises a substantially sealed chute assembly in operable and sealed communication with a hammermill housing operably surrounding the hammermill portion of said rotary hammermill means so as to communicate with the bottom end of said hammermill housing at said first end of said hammermill transmission means,

said hammermill transmission means communicating with said liquid solid particle separation means at said second end.

23. The invention according to claim 1 in which said liquid solid particle separation means comprises;

a substantially sealed particle separator housing means operably attached, in sealed fashion, to the second end of said hammermill transmission means;

particle separator entry means immediately adjacent the second end of said hammermill transmission means through which said disintegrated particles of solid waste and said enveloping-impregnating disinfectant liquid jointly enter said liquid solid particle separation means for separation therebetween;

continuous conveyor sieve means operably positioned immediately adjacent said particle separator entry means for collecting said solid particle--liquid solution therefrom and for separating said disinfectant liquid from said solid waste particles;

said conveyor sieve comprising a substantially continuous looped conveyor element formed by a plurality of interlocking articulated separator belt components;

each said separator belt component including means for attachment to immediately adjacent equivalently constructed separator belt components, a substantially planar surface for supporting said solid waste particles and a plurality of slotted apertures through which said disinfectant liquid may pass towards collection adjacent said liquid evacuation means;

said conveyor sieve powered by separator belt motor means to collect said particle-liquid solution on a continuous basis from said hammermill transmission means;

said conveyor sieve further positioned in a substantially upwardly inclined orientation to deliver said solid waste particles to said solid particle evacuation means and direct the flow of said separated disinfectant liquid to said liquid evacuation means for subsequent independent disposal of same, respectively.

24. The invention according to claim 23 in which each of said separator belt component is possessed of said slotted apertures of a size capable of releasing the majority of disinfectant liquid mixed with said solid waste particles thereupon, while incapable of releasing any substantial volumes of solid waste particles therethrough so as to substantially direct most of said solid waste particles to said solid waste particle evacuation means.

25. The invention according to claim 24 in which said liquid-solid particle separation means further includes;

routing plate means positioned between the upper and lower portions of said substantially continuous conveyor sieve means;

said routing plate serving to direct both said separated disinfectant liquid and particles small enough to pass through said slotted apertures in said separator belt components away from the back side of the lower portion of said conveyor sieve to a position proximate to said liquid evacuation means,

said liquid-solid particle separation means further including conveyor sieve shoulder regions immediately proximate to the longitudinal edges of said conveyor sieve with a brush element positioned operably adjacent said longitudinal edges to further route said solid waste particles towards said solid-waste particle evacuation means;

said liquid-solid particle separation means including scraper means operably positioned immediately proximate said conveyor sieve and said solid waste evacuation means to direct said solid particles from said conveyor sieve into said solid waste evacuation means.

26. The invention according to claim 18 in which said outgoing flush conduits emanating from said bearing spacers are directed for routing said flushing fluid and any associated solid waste particles and disinfectant into said liquid-solid particle separation means for treatment therewithin.

27. The invention according to claim 1 in which said solid waste particle evacuation means has placement detection means operably associated therewith;

said detection means serving to deactivate operation of said liquid-solid particle separation means when said solid waste particle evacuation means is out of position.

28. The invention according to claim 1 in which said liquid evacuation means includes evacuation filter means to preclude the undesired evacuation of accumulated solid waste particles directly through said liquid evacuation means.

29. The invention according to claim 1 in which said system vacuum ventilation means comprises an operably connected series of respective housings about said waste delivery means, preliminary waste processing means, hammermill means and liquid solid separation means, together with said fragment solution channeling means, said hammermill solution transmission means and said one or more slitted draped curtains co-operating to form a substantially sealed uni-directional ventilation circuit,

said ventilation circuit being attached at said liquid-solid waste separation means to fan exhaust means for circulating air within said ventilation circuit in said one direction, through and out from same,

said rotary hammermill means further acting as supplemental exhaust means to augment the uni-directional exhausting of potentially bacteria-laden air therethrough, at an exhaust rate less than that of said fan exhaust means, to preclude the forced release of airborne contaminants emanating from said rotary hammermill means,

said air within said ventilation circuit being directed from said system input means towards said liquid solid separation means and, in turn, through and out said fan exhaust means.

30. The invention according to claim 29 in which said fan exhaust means comprises;

two or more independent ventilation circuit extension means operably attached, in substantially sealed affixation, to said solid-liquid particle separation means housing for channeling said air within said circuit therefrom;

filtering means operably associated with each of said two or more independent ventilation circuit extension means to filter mists, vapors, waste particles, and bacteria from said air prior to release therefrom;

a blower apparatus operably associated with each of said two or more independent ventilation circuit extension means for creating said uni-directional flow of said air, for driving same through each said filtering means and for ultimately discharging said filtered air from said waste disposal system.

31. The invention according to claim 30 in which each said filtering means includes a plurality of filtering media to filter said mists, vapors, waste particles and bacteria in said air,

said plurality of media including hoghair, polyester, pleated and hepa filtering media to effectively filter said air, prior to release of same from said waste disposal system.

32. The invention according to claim 31 in which each said filtering means includes filter monitoring detectors to disclose the occurrence of an overly saturated filtering media element to an operator of said waste disposal system.

33. The invention according to claim 1 in which said system switching control means includes computer controlled switching and sequencing apparata;

said computer controlled switching and sequencing apparata including monitor means with diagnostic means to disclose switching control sequencing operations and problems as they occur and including indicia output means for disclosure of said diagnostic messages.

34. The invention according to claim 33 in which said system switching control means further includes a remote test switching apparatus capable of being physically relocated to any position along said waste disposal system to enable the remote, isolated testing of any structural components thereof by one operator while permitting simultaneous viewing of the results of said switch testing.

35. The waste disposal system of claim 1 in which the invention further comprises elastomeric mounting means operably interposed among the supporting structures for one or more of said waste delivery means, preliminary waste processing means, rotary hammermill means, liquid-solid particle separation means, system vacuum ventilation means and system switching control means, to isolate and effectively reduce the extent of vibration and noise emanating from same.

36. The waste disposal system of claim 1 in which the invention further comprises;

component corrosion control means for spraying onto and through one or more of said waste delivery means, said disinfectant spray means, said preliminary waste processing means, said fragment solution channeling means, said rotary hammermill means and said hammermill solution transmission means, a corrosion preventive coating means when said system is not being used to treat and dispose of infectious waste articles.

37. The invention according to claim 36 in which said component corrosion control means includes said disinfectant spray means for emission of said corrosion preventive coating therefrom,

said corrosion preventive coating comprising a plurality of solutions sprayed upon and through said one or more means,

said plurality of solutions including a diluted solution of said disinfecting liquid solution, water, and finally, a solution of water-soluble oil and water for coating thereonto said one or more means of said waste disposal system.