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EP-2640522-B1 - SYSTEM AND METHODS FOR CONVERSION OF BIOHAZARD TO MUNICIPAL WASTE

EP2640522B1EP 2640522 B1EP2640522 B1EP 2640522B1EP-2640522-B1

Inventors

  • CARMEL, ITZHAK

Dates

Publication Date
20260506
Application Date
20111004

Claims (20)

  1. A method for shredding and separating liquids from medical waste, the method comprising: providing a rotating shredder (2) seated in a medical waste treating chamber (4) and an apertured partition (150) seated below the shredder and having at least one aperture (108) defined therewithin, thereby to partition the chamber into upper and lower compartments communicating only via the at least one aperture; and providing an aperture cleaner (105) below and fixedly associated with the rotating shredder and configured and arranged to sweep non-fluids away from said aperture as said rotating shredder rotates the medical waste treating chamber (4) being an interior of an enclosure disposed within an environment which is not to be polluted, the method also comprising: providing at least one high-speed seal (101) to seal off the interior from the environment; and providing a vacuum pump (14) operative to eliminate air pockets in the medical waste treating chamber and a steam generator (10) operative to generate steam in the chamber (4) after the air pockets have been eliminated, thereby to ensure steam sterilization of all waste in the chamber, thereby to pressurize a region adjacent the seal so as to deter sharp particles within the medical waste, from approaching the seal.
  2. A method according to claim 1, also including washing said chamber (4) with a fluid which flows into the lower compartment thereby to allow selective removal of the fluid but not of non-fluid waste, from the chamber, via the lower compartment.
  3. A method according to claim 1, also including flushing a fluid through medical waste in the chamber (4) to eliminate malodor, wherein the fluid flows into the lower compartment thereby to allow selective removal of the fluid but not of non-fluid waste, from the chamber, via the lower compartment.
  4. A method according to claim 1, wherein providing the shredder (2) includes providing a motor-driven shaft (17) and blades (18) rotated by the shaft (17), the shaft (17) extending through the enclosure thereby to define an interface between the waste treating chamber (4) and the environment, the method also comprising providing interface seal apparatus operative to prevent leakage of at least fluids from said medical waste treating chamber (4) into the environment, via the interface.
  5. A system for shredding and separating liquids from medical waste, the system comprising: a medical waste treating chamber (4); a rotating shredder (2) seated in the chamber; an apertured partition (150) seated below the shredder and having at least one aperture (108) defined therewithin, thereby to partition the chamber into two compartments communicating only via the at least one aperture; and an aperture cleaner (105) below and fixedly associated with the rotating shredder and configured and arranged to sweep non-fluids away from said aperture as said rotating shredder rotates the medical waste treating chamber (4) being an interior of an enclosure disposed within an environment which is not to be polluted, the system also comprising: at least one high-speed seal (101) to seal off said interior from the environment; a vacuum pump (14) operative to eliminate air pockets in the medical waste treating chamber; and a steam generator (10) operative to generate steam in the chamber after the air pockets have been eliminated, thereby to ensure steam sterilization of all waste in the chamber, thereby to pressurize a region adjacent the seal so as to deter sharp particles within the medical waste, from approaching the seal.
  6. A system according to claim 5, wherein said chamber (4) is cylindrical and has an axis and wherein said aperture cleaner (105) comprises at least one cleaning rod which is disposed at a radial distance relative to the axis and which extends from said rotating shredder downward toward said apertured partition (150) and wherein said apertured partition comprises a horizontal plate defining a centered circular track (180) of radius r along which a plurality of apertures are defined and along which the rod travels when the shredder (2) is rotating, thereby to sweep non-fluids away from said plurality of apertures.
  7. A system according to claim 5, also comprising at least one internal liquid sprinkler (13) using sprinkled liquid to provide automatic cleaning of said medical waste treating chamber (4) and wherein said sprinkled liquid travels through said at least one aperture.
  8. A system according to claim 5, wherein said at least one aperture partition (150) has top and bottom surfaces and said at least one aperture defines a first hole in said top surface and a second hole, in said bottom surface, which is larger than said first hole, thereby to prevent particles from blocking the aperture.
  9. A system according to claim 5, wherein the medical waste treating chamber (4) is an interior of an enclosure disposed within an environment which is not to be polluted; a motor; the shredder (2) including a motor-driven shaft (17) and blades (18) rotated by the shaft, the shaft extending through the enclosure thereby to define an interface between the waste treating chamber (4) and the environment, the system also comprising interface seal apparatus preventing leakage of at least fluids from said medical waste treating chamber into the environment, via the interface.
  10. A system according to claim 5, the medical waste treating chamber (4) being an interior of an enclosure and wherein the shredder (2) includes a motor-driven shaft (17) and blades (18) rotated by the shaft (17), the shaft (17) extending through the enclosure thereby to define an interface between the waste treating chamber (4) and the environment, the system also comprising interface seal apparatus preventing leakage of at least fluids from said medical waste treating chamber (4) into the environment, via the interface, the apparatus including one or more high-speed seal/s to seal off the interior from the environment; and wherein an external threading (190) is provided on said shaft (17) such that when said shaft (17) rotates and said medical waste treating chamber (4) is pressurized, sharp medical waste particles detrimental to said seals are propelled by said threading (190), away from said seals.
  11. A system according to claim 5, wherein said medical waste treating chamber (4) is defined by an enclosure having an opening at its top for introducing medical waste to be treated into said medical waste treating chamber (4) and wherein said system includes a chamber upender to up-end the chamber thereby to remove treated medical waste therefrom via said opening.
  12. A system according to claim 5, wherein the medical waste treating chamber (4) is generally cylindrical and has a bottom portion and wherein said shredder (2) is seated in the bottom portion of the medical waste treating chamber, and wherein a motor (11a) is external to the medical waste treating chamber (4) and wherein said shredder (2) includes a motor-driven shaft (17) and blades (18) rotated by the shaft (17), the shaft (17) extending through the enclosure thereby to define an interface between the waste treating chamber and the environment; and wherein said interface is generally cylindrical.
  13. A system according to claim 5, also comprising a steam delivering conduit (111) leading from the steam generator (10) to an area adjacent said high speed seal (101) thereby to prevent formation adjacent said at least one seal, of a region whose pressure is low, relative to medical waste treating chamber pressure, which consequently would attract sharp medical waste particles to said seals, low pressure region formation being prevented by steam pressurizing the area adjacent each of said high speed seals just prior to steam pressurization of the medical waste treating chamber (4).
  14. A system according to claim 5, wherein the steam generator (10) is operative to cause steam to be present adjacent the seal.
  15. A system according to claim 9, wherein said interface has an internal end disposed interiorly of said enclosure and an external end disposed exteriorly of said enclosure, and wherein said interface seal apparatus comprises: first and second high-speed seals (101) sealing off said internal and external ends of said interface respectively, such that unless the high-speed seals have degraded, said leakage is prevented even when said shredder is operating at high speed.
  16. A system according to claim 9, wherein the medical waste treating chamber (4) is generally cylindrical and has a bottom portion and wherein said shredder (2) is seated in the bottom portion of the medical waste treating chamber, and wherein the motor is external to the medical waste treating chamber and wherein said interface is generally cylindrical.
  17. A system according to claim 9 and also comprising a steam sterilizer operative to steam-sterilize contents of the medical waste treating chamber (4).
  18. A system according to claim 15 and also comprising a lubricant chamber (106) of pressurized lubricant surrounding, thereby to reduce degradation of said seals and maintained at a pressure which exceeds pressure in the medical waste treating chamber (4).
  19. A system according to claim 15 and also comprising a cone (107) whose apex faces upwards embracing the shaft (17) encasing said high speed seals such that if pressure in an area adjacent at least one of the high speed seals is equal to pressure in the medical waste treating chamber (4) as a whole, sharp medical waste particles do not climb up said cone, hence do not reach said seals.
  20. A system according to claim 18 and also comprising a pressure sensor (12a) measuring pressure in the lubricant chamber and alerting for seal degradation if the pressure in the lubricant chamber drops below a predetermined level.

Description

FIELD OF THE INVENTION The present invention relates generally to medical waste treatment and more particularly to systems for sterilization of medical waste. BACKGROUND OF THE INVENTION Conventional technology pertaining to treatment of medical waste is described in the following US patent documents inter alia: 5078924; 5163375; 5240187; 5236135; 5271892; 5348235; 5362443; 5387350; 5401444; 5458072; 5508004; 5580521; 5639031; 5830419; 5833922; 6039724; 6113854; 7144550; 7718120; 7814851; 7815851; Hospitals and other facilities generate large amounts of medical waste daily. Existing techniques for treatment of medical waste are so unsatisfactory that some health facilities in first-world countries elect to convey only partially neutralized medical waste to poorly regulated third-world countries for disposal, thereby causing dangerous planet-wide pollution. Existing medical waste treating systems are characterized by one or more of the following: large size necessitating a facility located at a distance from the hospital or other waste-generating facility rather than within the hospital; failure to achieve adequate de-contamination; generation of large volumes of waste which are costly to dispose of due to high per-volume disposal costs; generation of a strong, unpleasant odor; requirement for distasteful manual handling e.g. to empty the system's chamber of processed waste which did not exit automatically. ECODAS is an example of a conventional system that is said to sterilize Regulated Medical Waste (RMW), reduce its volume by 80%, and render its components unrecognizable, by shredding and direct pressurized heated steam all in one enclosed system achieving complete sterilization of infectious materials. The final treated waste is said to be harmless, unrecognizable, and safe for disposal, just like ordinary municipal waste. Shredding is followed by superheated steam (138°C/280°F) under high pressure (3.8 bars/55 psi) which destroys all forms of microbial life. SUMMARY OF THE INVENTION The invention relates to a method for shredding and separating liquids from medical waste according to claim 1, as well as to a system for shredding and separating liquids from medical waste according to claim 5. Further features of the invention are described in the dependent claims. Certain embodiments of the present invention seek to provide a system for treatment of medical waste in a sterilizer, which uses both vacuum and pressure, whilst cutting the waste, thereby replacing air pockets in the chamber with steam, so as to enhance sterilization. Certain embodiments of the present invention seek to provide a reason for using vacuum is to replace the air pockets in the chamber with steam so as to achieve sterilization. Typically a mechanism is provided that creates vacuum while cutting, while preventing small parts, glass, metal etc. entering into the sealing of the unit and destroying it. Certain embodiments of the present invention seek to provide the ability to filter out and drain liquids from a chamber which performs sterilization and shredding, e.g. without shredded sharp matter blocking filters, including liquids accumulating from the treatment and or liquid used to wash the unit. Certain embodiments of the present invention seek to provide a shaft mechanism which rotates inside an external pressure tank, to prevent bio-hazardous gases/liquids from being exhausted from the main waste treating chamber through the shaft. Certain embodiments of the present invention seek to provide a mechanism which protects gaskets from dirt or shredded particles e.g. metal/glass/crystals, contact with which during the cycle would damage the gaskets. Certain embodiments of the present invention seek to provide a compact Integrated Sterilizer & Shredder (ISS) for on-site conversion of biohazard to municipal waste rapidly e.g. in as little as 25 minutes. The ISS typically performs both size reduction and waste steam sterilization in a single vessel. The vessel is typically fitted with a motor-driven shaft, with shredding/crushing blades. Shredding the waste ensures an acceptable level of sterilization. Shredded waste is typically reduced to as little as 1/10 its original volume, without emitting harmful substances. The vessel may be supported by two arms which are typically also used to rotate the vessel e.g. for 2 or more of loading (45° e.g.), treatment (0° e.g.) and unloading (135° e.g.) positions. The vessel is typically turned by a motor, and the positions are typically indicated by magnetic switches. The unit typically includes an internal steam generator, automatically controlled by the electronic system. The vessel is typically constructed with internal sprinklers for an automatic cleaning process. The vessel is typically equipped with a multipurpose shredder/ crusher blade on the bottom, regulated by an electric motor which drives the knife shaft. The shaft typically connects the knife to the motor through the bearing housing a