System and methods for conversion of biohazard to municipal waste

Abstract

A system for shredding medical waste, the system comprising a medical waste treating chamber being an interior of an enclosure disposed within an environment which is not to be polluted, a motor, a shredder seated in the chamber and including a motor-driven shaft and blades rotated by the shaft, the shaft extending through the enclosure thereby to define an interface between the waste treating chamber and the environment, and interface seal apparatus preventing leakage of at least fluids from the medical waste treating chamber into the environment, via the interface.

Claims

1. A system for shredding and separating liquids from medical waste, the system comprising: a medical waste treating chamber; a rotating shredder seated in the chamber; an apertured partition seated below the rotating shredder and having at least one aperture defined therewithin, thereby to partition the chamber into two compartments communicating only via the at least one aperture; and an aperture cleaner below, and fixedly associated with, the rotating shredder and configured and arranged to sweep non-fluids away from said at least one aperture as said rotating shredder rotates; the medical waste treating chamber being an interior of an enclosure disposed within an environment; the system also comprising: at least one high-speed seal to seal off said interior from the environment; and a steam generator operative to generate steam in the chamber by pressuring a region adjacent the at least one high-speed seal so as to deter sharp particles within the medical waste, from approaching the at least one high-speed seal.

2. The system according to claim 1 wherein said chamber is cylindrical and has an axis and wherein said aperture cleaner 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 and wherein said at least one aperture comprises a plurality of apertures and wherein said apertured partition comprises a horizontal plate defining a centered circular track of radius r along which said plurality of apertures are defined and along which the at least one cleaning rod travels when the rotating shredder is rotating, thereby to sweep non-fluids away from said plurality of apertures.

3. The system according to claim 1 and also comprising at least one internal liquid sprinkler using sprinkled liquid to provide automatic cleaning of said medical waste treating chamber and wherein said sprinkled liquid travels through said at least one aperture.

4. The system according to claim 1 wherein said aperture partition 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 at least one aperture.

5. The system according to claim 1, the rotating shredder including a motor-driven shaft and blades rotated by the shaft, the shaft extending through the enclosure thereby to define an interface between the waste treating chamber 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, thereby to prevent pollution of an environment within which the enclosure is disposed.

6. The system according to claim 5 wherein the medical waste treating chamber is cylindrical and has a bottom portion and wherein said rotating shredder 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 cylindrical.

7. The system according to claim 5, the system comprising: an apertured partition seated below the rotating shredder and having at least one aperture defined therewithin, thereby to partition the chamber into two compartments communicating only via the at least one aperture; and an aperture cleaner below, and fixedly associated with, the rotating shredder, configured and arranged to sweep non-fluids away from said at least one aperture as said rotating shredder rotates.

8. The system according to claim 5 and also comprising a steam sterilizer operative to steam-sterilize contents of the medical waste treating chamber.

9. The system according to claim 1, the system also comprising: a vacuum pump operative to eliminate air pockets in the medical waste treating chamber.

10. The system according to claim 1 and also comprising a steam delivering conduit leading from the steam generator to an area adjacent the at least one high-speed seal thereby to prevent formation adjacent the at least one high-speed seal, of a region whose pressure is low, relative to the medical waste treating chamber pressure, which consequently would attract sharp medical waste particles to the at least one high-speed seal, low pressure region formation being prevented by steam pressurizing the area adjacent the at least one high-speed seal just prior to steam pressurization of the medical waste treating chamber.

11. A method for shredding and separating liquids from medical waste, the system comprising: providing a rotating shredder seated in a medical waste treating chamber and an apertured partition seated below the rotating shredder and having at least one aperture 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 below, and fixedly associated with, the rotating shredder and configured and arranged to sweep non-fluids away from said at least one aperture as said rotating shredder rotates; the medical waste treating chamber being an interior of an enclosure disposed within an environment; the method also comprising: providing at least one high-speed seal to seal off said interior from the environment; and providing a steam generator operative to generate steam in the chamber by pressuring a region adjacent the at least one high-speed seal so as to deter sharp particles within the medical waste, from approaching the at least one high-speed seal.

12. The method according to claim 11 and also including washing said chamber 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.

13. The method according to claim 11 and also including flushing a fluid through medical waste in the chamber 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.

14. The method according to claim 11, wherein providing the rotating shredder includes providing a motor-driven shaft and blades rotated by the shaft, the shaft extending through the enclosure thereby to define an interface between the waste treating chamber 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 into the environment, via the interface, thereby to prevent pollution of an environment within which the enclosure is disposed.

15. The method according to claim 11, the method also comprising: providing a vacuum pump operative to eliminate air pockets in the medical waste treating chamber, and wherein the steam generator is operative to generate the steam in the chamber after the air pockets have been eliminated, thereby to ensure steam sterilization of all waste in the chamber.

16. A system for shredding and separating liquids from medical waste, the system comprising: a medical waste treating chamber; a rotating shredder seated in the chamber; and an apertured partition seated below the rotating shredder and having at least one aperture defined therewithin, thereby to partition the chamber into two compartments communicating only via the at least one aperture; the medical waste treating chamber being an interior of an enclosure disposed within an environment, the system also comprising: at least one high-speed seal to seal off said interior from the environment; and a steam generator operative to generate steam in the chamber by pressuring a region adjacent the at least one high-speed seal so as to deter sharp particles within the medical waste, from approaching the at least one high-speed seal.

17. The system according to claim 16 wherein said chamber is cylindrical and has an axis and also comprising an aperture cleaner which 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, and wherein said at least one aperture comprises a plurality of apertures and wherein said apertured partition comprises a horizontal plate defining a centered circular track of radius r along which said plurality of apertures are defined and along which the at least one cleaning rod travels when the rotating shredder is rotating, thereby to sweep non-fluids away from said plurality of apertures.

18. The system according to claim 16 and also comprising at least one internal liquid sprinkler using sprinkled liquid to provide automatic cleaning of said medical waste treating chamber and wherein said sprinkled liquid travels through said at least one aperture.

19. The system according to claim 16 wherein said apertured partition 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 at least one aperture.

20. The system according to claim 16 and also comprising: a vacuum pump operative to eliminate air pockets in the medical waste treating chamber, and a steam generator 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.

21. The system according to claim 16 wherein said medical waste treating chamber is defined by an enclosure having an opening at its top for introducing medical waste to be treated into said medical waste treating chamber and wherein said system includes a device arranged and operative to up-end the chamber thereby to remove treated medical waste therefrom via said opening.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIGS. 1a-1c are simplified pictorial illustrations of respective possible positions of an Integrated Sterilizer & Shredder (ISS) system for on-site conversion of biohazard to municipal waste, all constructed and operative in accordance with an embodiment of the present invention.

(2) FIGS. 2a-2b, taken together, form a simplified flowchart illustration of an example method of operation for an example ISS (steam sterilizer with an integrated shredder), constructed and operative in accordance with an embodiment of the present invention.

(3) FIGS. 3a and 3b illustrate a knife block or knife module performing the shredding functionality of the system of FIGS. 1a-1c, the module including blades as well as associated elements providing rotation such as bearings and gaskets, all constructed and operative in accordance with an embodiment of the present invention.

(4) FIGS. 4a-4c are respective sectional, cut-away isometric and isometric illustrations of a bottom portion of an integrated steam sterilization and shredding system according to an embodiment of the invention which is particularly suited to preventing debris, particularly sharp particles, from contacting high speed seals 101 which seal off the chamber 4, at the location in which the shaft 17 extends through the wall of the chamber 4.

(5) FIG. 5 is a magnification of the bubble 111a drawn in FIG. 4b showing a conduit 111 which is typically the only communication path between the debris in the chamber 4 and the seals 101, all being constructed and operative in accordance with an embodiment of the present invention.

(6) FIGS. 6a and 6b are respective cut-away perspective and perspective views of the cone 107 of FIG. 4b, according to an embodiment of the invention.

(7) FIGS. 7a, 7b and 7c are respective views of the shaft 17 of FIG. 4b and external threading 190 provided thereupon according to an embodiment of the invention.

(8) FIG. 8 is a front view of an integrated sterilizer & shredder system in accordance with certain embodiments of the present invention, shown with opened top lid when the assembled vessel, including waste chamber, is in a vertical position, and wherein two side shafts are provided to enable rotating of the waste chamber e.g. between the positions shown in FIGS. 1a-1c, e.g. by means of a chain sprocket.

(9) FIGS. 9a-9f, 10 are respective views of components of a fluid straining and disposal subsystem including an apertured partition operative to partition a waste treating chamber into two compartments such that fluid collects in the lower of the two compartments and non-fluids remain in the upper of the two compartments, all as constructed and operative in accordance with an embodiment of the present invention.

(10) FIGS. 11a-d, 12a-12d, 13a-13e, 14a-14e, 15 and 17-18 are illustrations, diagrams and tables describing various embodiments of an example ISS (steam sterilizer with an integrated shredder), for treatment of medical waste.

(11) FIG. 16 is a graph of pressure (dotted line) and temperature (dashed line) vs. time, useful in understanding certain embodiments of the present invention.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

(12) Reference is now made to FIGS. 1a-1c which are simplified pictorial illustrations of respective possible positions of an Integrated Sterilizer & Shredder (ISS) system for on-site conversion of biohazard to municipal waste.

(13) Typically, the system shown and described herein includes some or all of the following subsystems:

(14) a. a medical waste treating chamber being an interior of an enclosure disposed within an environment which is not to be polluted;

(15) b. a shredding subsystem including, typically, a motor external to the medical waste treating chamber and a shredder seated in the chamber and including a motor-driven shaft and blades rotated by the shaft, the shaft extending through the enclosure thereby to define a cylindrical (e.g.) interface between the waste treating chamber and the environment; high-speed seals to seal off the interface; and a lubricant chamber of pressurized lubricant surrounding, thereby to reduce degradation of said first and second seals and maintained at a pressure which exceeds pressure in the medical waste treating chamber.

(16) Typically, a Pressure Sensor 12a (such as, for example, a commercial pressure transducer 0 to 6 bar ABS. cat 514.99012, from Huba control Swiss or perhaps, in certain embodiments, a Xi'an Chinastar M&C Limited, CS-PT1100A 0-6 bar pressure sensor) measures pressure in the lubricant chamber and alerts for seal degradation if the pressure in the lubricant chamber drops below a predetermined level. The first pressure sensor 12a provided for the lubricant chamber is suitably positioned, e.g. as shown in FIG. 4c.

(17) Typically, a steam delivering conduit leads from a steam generator to an area adjacent each of the high speed seals thereby to prevent formation adjacent said seals, 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 conduit just prior to steam pressurization of the medical waste treating chamber. Typically, the architecture is such that the only communication path between the debris in the chamber and the seals is via a typically inclined conduit defined by a ramp structure, also termed herein a cone, such that debris needs to rise along the inclined plane defined by the cone in order to reach the seals. Typically, steam is pushed along the conduit which is the only communication path between the debris in the chamber and the seals to further prevent the debris from reaching the seals. The seals are typically 15 located in an area whose pressure is high relative to the pressure in the chamber such that a pressure gradient prevents debris from reaching the seals. The shaft typically has external threading configured and arranged, e.g. relative to the conduit which is the only communication path between the debris in the chamber and the seals, to carry debris away from the seals as the shaft rotates.

(18) c. a sterilization subsystem typically including a steam sterilizer operative to steam-sterilize contents of the medical waste treating chamber, wherein the sterilizer may include a vacuum pump operative to eliminate air pockets, which resist sterilization, in the medical waste treating chamber; and a steam generator 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.

(19) d. a fluid-utilization and/or straining and disposal subsystem (FIGS. 9a-9f, 10) including an apertured partition seated below the shredder and having at least one aperture defined therewithin, thereby to partition the chamber into two compartments communicating only via the at least one aperture; and an aperture cleaner below and fixedly associated with the rotating shredder and configured and arranged to sweep non-fluids away from said aperture as said rotating shredder rotatessaid aperture cleaner comprises at least one cleaning rod (e.g. mounted on or integrally formed with a shredder blade) which is disposed at a radial distance r relative to the axis and which extends from said rotating shredder downward toward said apertured partition and wherein said apertured partition comprises a horizontal plate defining a centered circular track of radius r along which a plurality of apertures are defined and along which the rod travels when the shredder is rotating, thereby to sweep non-fluids away from said plurality of apertures. The above arrangement allows flushing waste to eliminate malodor and/or use of an internal liquid sprinkler (e.g. PNR, DDW 2294 B1) for automatic cleaning of said medical waste treating chamber and wherein said sprinkled liquid travels through said at least one aperture.

(20) A particular advantage of the apertured partition, which is swept free of debris as described above, is that it is effective to partition the waste treating chamber into two compartments such that fluid collects in the lower of the two compartments and non-fluids remain in the upper of the two compartments.

(21) As shown, typically, rather than providing mill-wheels for reducing size of bio-hazardous matter, a shredder 2 is provided within a chamber 4 which holds the bio-hazardous waste to be converted. A particular advantage of certain embodiments is that the shredder allows the chamber to be more compact than the mill-wheels would; since mill-wheels both occupy space and typically require a double allocation of space for the bio-hazard, both above the wheels for pre-milled waste material and below the wheels for milled waste material. A motor 11a, typically external to the chamber 4, drives the typically rotational motion of the shredder 2 blades. Once waste has been shredded, a steam generator 10 supplies steam to the chamber, thereby to effectively, due to the small size of the shredded particles, steam-sterilize contents of the medical waste treating chamber.

(22) It is appreciated that medical waste treating chamber 4 typically comprises an interior of an enclosure disposed within an environment which is not to be polluted. Shredder 2, seated in the chamber 4, typically includes a shaft 17 driven by a motor 11 and at least one blade assembly 18 rotated by the shaft 17. According to certain embodiments, at least one and typically more than one blade assembly 18 is provided, typically including a horizontal blade 18a and a top blade 18b, e.g. as shown in FIG. 9a.

(23) If the motor 11a is external to the medical waste treating chamber 4, the shaft extends through the enclosure thereby to define a cylindrical (e.g.) interface between the waste treating chamber and the environment.

(24) Typically, another motor, termed herein motor 11b and not shown, turns the chamber 4 up-side down and then back up again. The door 6 of the chamber 4 may be operated by a cylinder (pneumatic system).

(25) Typically, high-speed rotatable seals 101 are used to seal the cylindrical interface off thereby maintaining complete isolation of the waste treating chamber's interior, relative to the environment. Typically, a chamber or tank 106 of pressurized lubricant surrounds the seals, thereby to reduce degradation thereof. The lubricant, which may for example comprise a suitable oil, such as but not limited to a conventional high temperature (180 degrees C.) oil lubricant, may be maintained at a pressure which exceeds pressure in the medical waste treating chamber.

(26) Typically, a Pressure Sensor 12a is provided for measuring pressure in the lubricant chamber 106 and alerting for seal degradation if the pressure in the lubricant chamber drops below a predetermined level.

(27) According to certain embodiments, an apertured partition (also termed herein hole plate or strainer plate) 150 (FIGS. 9a-9f, 10) is seated below the shredder and has at least one aperture 108 defined therewithin, thereby to partition the chamber into two compartments, an upper compartment 160 which retains non-fluid material and a lower compartment 170 for accumulating and drawing off liquid, which communicates with the upper compartment only via the at least one aperture. Each aperture 108 typically is generally conical in configuration with the wide end pointing downward, e.g. as shown.

(28) Typically, an aperture cleaner 105 (which may for example be formed of or mounted on a shredder blade) is disposed below and fixedly associated with the rotating shredder and is configured and arranged to sweep non-fluids away from said aperture as said rotating shredder rotates. Aperture cleaner 105 comprises at least one cleaning rod (or a pair of such rods, as indicated by the two reference numerals 105 in FIG. 10), which is disposed, e.g. held by a radial arm, at a radial distance r relative to the axis of rotation of the shredder 2 and which extends downward from the shredder 2 toward said apertured partition 150.

(29) Typically, an internal liquid sprinkler (FIG. 11a) is provided which uses sprinkled liquid to provide automatic cleaning of said medical waste treating chamber and/or to flush waste so as to eliminate malodor. The sprinkled liquid travels through said at least one aperture, thereby accumulating in the bottom compartment for selective liquid-only evacuation from the chamber 4, e.g. to the local sewer system, such that non-liquids which are ineligible to enter the sewer system, remain inside the chamber.

(30) Typically, vacuum is created in the chamber 4 before steam is introduced, so as to eliminate air pockets which would compromise the efficacy of the steam sterilization. A vacuum pump 14 (e.g. Speck, VI 8) may be provided for this purpose. The steam generator 10 (e.g. such as the example steam generator shown in FIG. 13a) may then generate steam in the chamber, after the air pockets have been eliminated, thereby to ensure steam sterilization of all waste in the chamber 4.

(31) Typically, a cone 107 (also termed herein ramp channel 107) whose apex faces upward embraces the shaft 17, encasing the high speed seals 101, such that if the pressure adjacent the seals is equal to pressure in the medical waste treating chamber as a whole, sharp medical waste particles nonetheless do not reach said seals because they do not climb up the cone.

(32) Typically, a steam delivering conduit leads from steam generator 10 to an area adjacent each of said high speed seals 101, e.g. the area encased by cone 107, thereby to prevent formation adjacent said seals, of a region whose pressure is low, relative to medical waste treating chamber pressure. If a low-pressure region were to form adjacent the seals, this region would attract sharp medical waste particles to said seals 101. Low pressure region formation is prevented by steam pressurizing the area adjacent each of said high speed seals 101 to create a pressure gradient sufficient to keep any sharp matter away from the seals, just prior to steam pressurization of the medical waste treating chamber 4.

(33) Steam generator 10 may comprise a Tuttnauer Israel 18 KW electrical steam source or any other suitable steam source. Steam generator 10, vacuum pump 14, and a control box 16 which controls operation of the apparatus as a whole, are typically not location sensitive. An example implementation of control box 16 is provided herein with reference to FIGS. 12a-12d, 17 and 18. An example implementation of steam generator 10 is shown in FIG. 13a.

(34) A first pressure sensor 12a may be provided for the lubricant chamber and is suitably positioned, e.g. as shown in FIG. 4c. A second pressure sensor 12b may be provided for the waste chamber and is suitably positioned, e.g., as shown, on the right side on top of the holder 8 of the door 6 of the chamber 4; the sprinkler 13 may point downward from the bottom surface of the middle of the cover or door of the chamber 4. A third conventional pressure sensor termed herein sensor 12c may be provided for the steam pressure source, which may be a separate unit which is not integrally formed with the waste chamber.

(35) Motor 11a, operating the blades of the shredder 2, may for example comprise an SMEM, SM112M2-2B3 (5.5 kW 2p IEC 112 B3 400V 50 Hz IP55). A suitable separate Motor e.g. SMEM, SM080A4B14 (0.55 KW 4P B14 IEC80 400V 50 Hz), may move the waste chamber from one to another of its orientations as shown in FIGS. 1a-1c.

(36) An example method of operation (Cycle Sequence) for the system shown and described above is now described with reference to FIG. 11a. The method may include some or all of the following steps or stages, suitably ordered e.g. as follows:

(37) Loading: waste is loaded into the chamber 4, chamber's door closes. Then, chamber rotates to process position e.g. fully vertical as shown in FIG. 1c.

(38) Shredding: The shredder 2 starts working with the start of the cycle at different speeds, as required. The shredder 2 continues working in high speed for 2 minutes. After this time elapses, the shredder 2 stops working.

(39) Sterilization: The cycle starts with one vacuum pulse to 35 kPa, to remove the air from the chamber 4.

(40) Heating: Steam is introduced into the chamber until sterilization temperature is reached, e.g. 134 C. and pressure of 312 kPa. Temperature and pressure are controlled at the required sterilization level for the duration of sterilization.

(41) A Bio Filter valve (VI in FIG. 11a) typically operates in shoot mode e.g. 3 seconds opened and 30 seconds closed, throughout the sterilization stage.

(42) Exhaust: the shredder starts working at low speed. A top exhaust valve 150 opens to reduce pressure via the bio-hazard filter of FIG. 11a down to 150 kPa (Exhaust Press parameter). When pressure is lower than 150 kPa, a fast exhaust valve opens.

(43) Drain: Liquids and steam are rapidly exhausted from the chamber to the drain box, until pressure equalizes atmospheric pressure. The shredder's blades typically are operational in this stage.

(44) Drying: vacuum is created in the chamber for 5 min During the drying stage, the Bio-Filter out valve VI of FIG. 11a may operate in shoot mode of 2 seconds On and 45 seconds Off. Atmospheric pressure is achieved in the chamber by controlling the compressed air to chamber and the top exhaust valves via the bio-hazard filter, until the end of the cycle.

(45) Unloading: typically, the chamber rotates to its unloading position (FIG. 1b) and the waste is evacuated to the bin.

(46) An example method of operation of the system of the present invention is shown in FIGS. 2a-2b. The method of FIGS. 2a-2b typically includes some or all of the following steps, suitably ordered e.g. as shown; it is appreciated that all parameter values are merely exemplary since these values may be determined by a person skilled in the art:

(47) Step 15: Loading: waste is loaded into the chamber 4, chamber's door closes. Then, chamber rotates to process position e.g. fully vertical as shown in FIG. 1c.

(48) Step 20: Shredding: The shredder 2 starts its operation, typically at different speeds, as appropriate to the application. For example, the shredder may initially operate back/forward at high speed, e.g. 3 seconds forward, 3 seconds backward, for 3 minutes, and then subsequently may operate 30 seconds forward, 30 seconds backward, again at high speed till exhaust stage (step 50 below).

(49) Step 30: Prevacuum: The cycle starts with one vacuum pulse to 35 kPa, to remove the air from the chamber 4.

(50) Step 40: Heating: Steam is introduced into the chamber until sterilization temperature is reached, e.g. 134 C. and pressure of 312 kPa. temperature and pressure are controlled at a suitable sterilization level for the duration of sterilization. A Bio Filter valve (e.g. VI in FIG. 11a) typically operates in shoot mode e.g. 3 seconds opened and 30 seconds closed, throughout the sterilization stage.

(51) Step 45: Sterilization: Temperature and pressure are maintained at a suitable 30 level, e.g. 134+4 and 312 kPa+28 kPa, for 5 minutes.

(52) Cycle fail: If during the sterilization process, the cycle fails, the system goes automatically to fail mode: e.g. displays warning icon and/or text that describes the failure. The system immediately goes to special exhaust mode that reduces pressure and temperature via a bio-filter to safety conditions.

(53) Step 50: Exhaust: the shredder starts working at low speed. A Top exhaust valve 150 opens to reduce pressure via the bio-hazard filter (e.g. as shown in FIG. 11a) down to 150 kPa (Exhaust Press parameter). When pressure is lower than 150 kPa, a Fast Exhaust valve opens.

(54) Step 60: Drain: Liquids and steam are rapidly exhausted from the chamber to the drain box, until pressure equalizes atmospheric pressure. The shredder's blades typically are operational during this stage.

(55) Step 70: The shredder blades operate at slow speed. Pulses of pressure 100 kPa (low)/115 kPa (High) in the chamber may be created with periodic operation of the Fast Exhaust valve and Compressed air to the chamber valve for 5 minutes. Atmospheric pressure is achieved in the chamber by controlling the Compressed air to chamber and the top Exhaust valves via the bio-hazard filter, until the end of the cycle.

(56) Step 80: Unloading: typically, the chamber rotates to its unloading position (FIG. 1b) and the waste is evacuated to the bin.

EXAMPLE

(57) The ISS may be constructed of carbon steel and have a total height of 2 m. The cylindrical (e.g.) vessel may be constructed of Stainless Steel 316 L, 160 liters (150 liters net) for 16-25 Kg, with one automatic hinge door. The motor is of 5.5 kW and is sufficient to rotate the shaft with an RPM of 300-1400 for various operations. The blade is made of high carbon steel with hardened cutting edges. Technical Specifications may be as stipulated in the table of FIG. 14a. The example system typically complies with some or all of the following standards & directives:

(58) EN 60204-1, Safety of machineryElectrical equipment of machinesGeneral requirements;

(59) EN 61000-6-2 Electromagnetic compatibility (EMC)Generic standardsImmunity for industrial environments;

(60) EN 61000-6-4 Electromagnetic compatibility (EMC)Generic standardsEmission standard for industrial environments.

(61) Machinery Directive-2006/42/EC; Pressure Equipment Directive-PED 97/23/EC; EMC Directive 89/336/EEC Article 7 (1); Low Voltage Equipment Directive 2006/95/EC.

(62) Quality Management System Standard: ISO 9001: 2008.

(63) FIGS. 3a and 3b are side and cross-sectional views of a knife block and associated lubricant chamber, constructed and operative in accordance with certain embodiments of the present invention.

(64) FIGS. 4a and 4b are respective sectional and isometric illustrations of a bottom portion of an integrated steam sterilization and shredding system according to an embodiment of the invention which is particularly suited to preventing debris, particularly sharp matter, from contacting high speed rotatable seals 101 which seal off the chamber 4, at the location in which the shaft 17 extends through the wall of the chamber 4.

(65) O-rings 102 provide a seal between the knife block's upper and lower portions, preventing escape of the lubricant and reduction of pressure in the lubricant chamber. Cylindrical roller bearing 103 and deep groove ball-bearing 104 facilitate rotation of the shaft rotate about its axis; bearing 103 copes with radial stresses and bearing 104 functions as a holder bearing.

(66) FIG. 5 is a magnification of the bubble 111a drawn in FIG. 4b showing a conduit 111 which is typically the only communication path between the debris in the chamber 4 and the seals 101. FIGS. 6a and 6b are respective views of the cone 107 of FIG. 4b, according to an embodiment of the invention. FIGS. 7a-7c are respective views of the shaft 17 of FIG. 4b and external threading 190 provided thereupon according to an embodiment of the invention.

(67) The bronze sleeve 131 generates a narrow steam-supplying channel, typically of less than 1 mm (e.g. approximately 0.5 mm) in diameter, between itself and the shaft. If the shaft rotates in a first, forward (e.g. clockwise) direction, together with the knives, then whenever any particles enter this gap, the rotation has the effect of pushing these back into the waste chamber, thereby preserving the cleanliness of the knife block and preventing malfunction as a result of blockage.

(68) As shown in FIGS. 3 and 4b, 5, 6a-6b and 7a-7c inter alia, a steam delivering path typically leads from a steam generator to an area adjacent each of the high speed seals 101 thereby to prevent formation adjacent seals 101, of a region whose pressure is low, relative to the pressure in medical waste treating chamber 4, which consequently would attract sharp medical waste particles to the seals 101. Low pressure region formation may be prevented by steam being fed along path 111, in a direction leading away from the seals, just prior to steam pressurization of the medical waste treating chamber 4.

(69) In the illustrated embodiment, the path 111 is adjacent to the shaft 17. The path 111, in the illustrated embodiment includes, proceeding in the direction in which steam is supplied, a first horizontal path segment or conduit segment 112, a first vertical segment 113, a second horizontal segment 115, a second vertical segment 117, a third horizontal segment 119, a third vertical segment 121 (which in the illustrated embodiment comprises a narrow channel between the shaft 17 and a typically bronze sleeve as shown), a fourth horizontal segment 123, an inclined segment 125, and a fifth horizontal conduit segment or path segment 127, however it is appreciated that this is not intended to be limiting. It is appreciated, however, that the path 111, if provided, need not have this particular configuration and may be designed in any suitable manner so as to provide a narrow steam channel preserving the cleanliness of the knife block and preventing malfunction as a result of blockage, as described herein, e.g. by causing a pressure gradient adjacent the seals which distances dirt particles from the seals by providing pressure under the ramp channel or cone 107, as high as or higher than the pressure in waste chamber 4.

(70) Typically, the architecture is such that the only communication path between the debris in the chamber and the seals is via a typically inclined conduit segment 125 typically defined by a ramp structure 107, also termed herein a cone, such that debris needs to rise along the inclined plane defined by the segment 125 in order to reach the seals 101. Typically, steam is pushed along the conduit 111 which is the only communication path between the debris in the chamber 4 and the seals 101 to further prevent debris from reaching the seals 101. The seals 101 are typically located in an area, e.g. the area below the cone 107, whose pressure is high relative to the pressure in the chamber such that a pressure gradient prevents debris from reaching the seals 101. As shown in FIGS. 7a-7c, the shaft 17 typically has external threading configured and arranged, e.g. relative to the conduit 111 which is the only communication path between the debris in the chamber and the seals, to carry debris away from the seals 101 as the shaft 17 rotates.

(71) As shown in FIG. 6a, the particle ramp 107 typically surrounds the shredder driving shaft 17 and shelters the seals, enabling a high pressure area to be maintained, below the particle ramp, adjacent the seals 101. The high pressure area is typically generated via a steam feeding channel 109.

(72) The path of the steam, which typically reaches the chamber along the inclined path segment 125, is shown by a dotted line 111 in FIG. 4b. Typically, the steam can only reach the chamber via path 111. The steam provided along the path 111 pushes debris away from the seals back to the chamber 4.

(73) The external thread 190 typically provided on the shaft 17 is advantageous in that, when the shaft 17 is rotating so as to drive the shredder blades 18, the thread 190 propels debris if any, out of the vicinity of the seals 101, through the conical ramp. Typically, provision of an inclined exclusive path for the debris as shown, makes it difficult for the debris to elevate, and this feature in combination with the steam pushed into the conduit 111 makes it extremely unlikely for debris to reach and damage the seals 101. A plug 194 (FIG. 4b) is typically provided to prevent leakage of the high pressure steam.

(74) FIG. 8 is a front view of an ISS system in accordance with certain embodiments of the present invention, shown with opened top lid when the assembled vessel, including waste chamber, is in a vertical position. Typically, as shown, two side shafts are provided to enable rotating of the waste chamber 4 e.g. between the positions shown in FIGS. 1a-1c, e.g. by means of a chain sprocket.

(75) An example Steam Sterilizer with an integrated shredder, intended for treatment of medical waste in hospitals and clinics, is now described in detail with reference to FIGS. 11a-11b, 12a-12c, 13a-13b, 14a-14d and 15.

(76) The system includes an electrically heated bio-hazard sterilizer, which operates with saturated steam as a sterilizing agent, and has a temperature range of up to 138 C. (280.4 F.) and pressure up to 2.4 bars (35 psi). The device includes a large steam sterilizer in accordance with EN285, continuously operated, optionally including only ordinary equipment without applied parts and without signal input-output parts.

(77) The Chamber and the Steam Generator may for example be constructed of stainless steel and the knife of carbon steel. Heating of the waste chamber 4 may be provided by saturated steam supplied by an external steam generator. Metal parts in the inner surfaces are also typically made of stainless steel. The device's chamber is, according to one embodiment, equipped with a single door, provided with an automatic locking mechanism, activated by compressed air, preventing the opening of the door by a safety lock.

(78) The IS S's operating cycles are typically user-specified. Only one general program may be available: Sterilization and shredding 134 C./10 Minutes, bottom (fast) exhaust, 5 minutes drying. In addition, a dynamic test program and a washing 5 cycle are available. The service cycles, e.g. as below, may be protected by code for operation by technical staff only: Sterilization and shredding 134 C./10 minutes without bottom (fast) exhaust. Sterilization 134 C./10 minutes without shredding, and without bottom exhaust (fast).

(79) The control system of the device is typically based on state of the art microcomputer technology, ensuring highly reliable and safe operation. The computerized control unit typically ensures fully automatic operation through the entire cycle; hence typically, after setting the pre-selected data and starting the operation, no further intervention is necessary.

(80) The selected program, the phases of the cycle and the status of the machine are typically controlled and displayed on digital readouts.

(81) For optimal control accuracy of the sterilization parameters, the system is equipped with temperature sensors PT100 and three pressure transducers having the following functions:

(82) A temperature sensor for chamber temperature

(83) A temperature sensor for the filter's temperature

(84) A temperature sensor for the drain box's temperature (control and monitoring).

(85) A pressure transducer for chamber pressure

(86) A pressure transducer for generator pressure (control of the generator and monitoring).

(87) A pressure transducer in the over-pressurized sealing area for the knife shaft (safety and monitoring).

(88) The panel located on the front panel typically enables the operator to start and stop the cycle.

(89) The operator starts the machine after putting the waste into the vessel.

(90) An example bio-hazard sterilizer and shredder is now described. It is appreciated that the particular characteristics thereof are not intended to be limiting and any individual parameter or characteristic set out herein may be modified or omitted as suitable.

(91) The ISS processes regulated medical waste into ordinary municipal solid waste. This means that the resultant sterile output can be safely disposed as regular municipal waste. The action of the shredding blades allows steam to penetrate the waste more efficiently and eliminates the possibility of cold spots. The resultant waste is typically unrecognizable and reduced by 50-80%. Post processing, the treated waste is suitable for regular disposal.

(92) As shown in the example piping diagram of FIG. 11a, operation may be as follows or any suitable variation or generalization of the following: after loading the chamber, the door automatically closes and the chamber rotates to working position (e.g. fully vertical). At this stage, one vacuum pulse of up to 35 kPa is implemented through valve no. 9, through the bio filter. After vacuum is created, steam is introduced through a lower steam filter (valve no. 3 in FIG. 11a), until sterilization temperature is achieved. The shredder blades start rotating from the moment of cycle starting.

(93) During inflation of the chamber with steam, the bio filter valve (6) is opened, until the steam replaces the air completely. This valve releases air through the bio-filter to the drain box. The drain box includes a float switch and a temperature sensor, to verify that no blockage has occurred, and to control the temperature of water going to the drain. In case of blockage, the exhaust is stopped and a failure indication will be provided. During sterilization, the bio filter functions as an integral part of the chamber being sterilized.

(94) Compressed air is introduced through valve no. 4 (Clean filter) to clean the filter.

(95) As described above, the vessel or chamber is equipped with a multipurpose shredder/crusher blade typically on the bottom, to ensure use of the full volume of the vessel. It is regulated by an electric motor which drives the knife shaft through a tooth belt. The shaft connects the knife to the motor through the bearing housing and the sealing area. The motor is of 5.5 kW and is sufficient to rotate the shaft with an RPM of, say, 300-1400 which, according to certain embodiments, depends on the operations being performed. For example, (a first and higher rotational speed, e.g. of 1330 rpm, may be provided for fast and fine shredding useful in order to eliminate large particles, whereas a second, lower rotational speed, e.g. of 300 rpm, may be provided for slow shredding and moving of particles to allow the steam to penetrate throughout the waste. The blades are mounted on the shaft and are typically designed to shred waste such as paper, textiles, plastic and glass. The blade is typically made of high carbon steel with hardened cutting edges.

(96) Utility connections may include an electricity connection, a mineral free water connection, an external steam connection, a water inlet, a drain outlet and a compressed air inlet. For example: Electrical: 400V 3-ph, 16 or 25 kW; External Steam: 30 KG/hr. at 6 bar; 30 l/min. cold water, connection; Drain: 2-4; Compressed Air: 6 bar; HVAC: Standard computer environment, 10 air exchanges/hour in room, machine connection to outside vent. The mineral-free water supplied to the steam generator, including steam supplied from boilers installed at the customer's site, which enters the sterilizer chamber, may have the physical characteristics and maximum acceptable level of contaminants indicated in the Maximum values of contaminants in Feed water and Condensate table of FIG. 14b.

(97) A reverse osmosis water purification system, e.g. as shown in FIG. 11b, is provided according to certain embodiments, in order to improve the quality of the water used to generate steam into the device's chamber. The use of mineral-free water contributes to better performance and longer life of the sterilizers' pipes and valves.

(98) The reverse-osmosis water purification system typically obviates any need to refill water reservoirs.

(99) A dynamic test is typically performed at intervals, e.g. at least once every working week, to detect leaks which under pressure may cause infection to the operator and the environment. Operations sequence of this test may include some or all of the following steps, suitably ordered e.g. as shown:

(100) Water and steam are introduced into the empty chamber at 138 C. for a preset pressure (2.4 bar), for 5 min.

(101) The shredder is operated to create a vortex.

(102) During periodic maintenance, or if a leak has been detected during this test, leak detection foam may be used to detect the source of leakages during this test.

(103) A suitable cleaning cycle operations sequence may include some or all of the following steps, suitably ordered e.g. as shown:

(104) Water and steam are introduced into the empty chamber for 5 min; steam is introduced to the filter to clean any remaining residues.

(105) The system holds a temperature of 60 C. in the chamber for 2 minutes, while the shredder works at high speed.

(106) Pressurizing the chamber to 150 kPa with steam and compressed air.

(107) Drainage of the water and residue into the drain box via the fast exhaust valve.

(108) Adding Water for 2 minutes. The shredder's motor is stopped.

(109) Pressurizing the chamber to 110 kPa with steam and compressed air.

(110) Drainage of the water into the drain box via the fast exhaust valve.

(111) FIG. 11a is a piping diagram of a shredder of an example ISS system constructed and operative in accordance with an embodiment of the present invention. The various components of the apparatus of FIG. 11a may, for example, be as indicated in the table of FIGS. 11c-11d.

(112) FIG. 12a is an electrical schematic diagram of the control part of an example ISS system constructed and operative in accordance with an embodiment of the present invention. The controller may for example comprise a SCS2-285 or any other suitable microprocessor (e.g. as per FIG. 12b). It is appreciated that FIG. 12a is merely an example of an overview of a possible control system with all inputs and outputs connected to the control system, as well as a main power supply. FIG. 12b is a zoom-in diagram of an example controller suitable for implementing the embodiment of FIG. 12a.

(113) FIGS. 12c and 12d are schematic diagrams of components useful in conjunction with the apparatus of FIG. 12a; in particular, FIG. 12C illustrates a CPanel including GUI operator panel with power supply and connection to the control system of FIG. 12b, e.g., through the communication connector marked 12c in FIG. 12B, left side, under RS232 connector. FIG. 12D illustrates a water pump valve which may be connected to a 24 VAC power and to the control system.

(114) FIG. 13a is a piping diagram of a steam generator of an example ISS system constructed and operative in accordance with an embodiment of the present invention. The various components of the apparatus of FIG. 13a may, for example, be as indicated in the table of FIG. 13c.

(115) FIG. 13b is a pneumatic diagram of an example ISS system constructed and operative in accordance with an embodiment of the present invention. The various components of the apparatus of FIG. 13b may, for example, be as indicated in the table of FIGS. 13d-13e.

(116) FIG. 14a is a table of specifications for an example ISS system constructed and operative in accordance with an embodiment of the present invention.

(117) FIG. 14b is a table of maximum contaminant values for an example ISS system constructed and operative in accordance with an embodiment of the present invention.

(118) FIG. 14c is a table of valve numbering, which is useful in understanding the piping diagram of FIG. 11a.

(119) FIG. 14d is a table of commercially available products which are examples of possible implementations of certain components of certain embodiments of the present invention, as indicated.

(120) FIG. 14e is a table of commercially available pressure sensors which are examples of possible implementations of certain pressure sensing components of certain embodiments of the present invention, as indicated.

(121) FIG. 16 is a graph of pressure (dotted line) and temperature (dashed line) vs. time. t1-t5 are time windows, not necessarily to scale, devoted respectively to Pre-vacuum, Heating to Sterilization Temperature (Ster. Temp), Sterilization, Exhaust and Dry functionalities.

(122) FIG. 17 is an electrical schematic diagram of an example control for the AC portion of an example ISS system constructed and operative in accordance with an embodiment of the present invention.

(123) FIG. 18 is an electrical schematic diagram of an example control for the steam generator part of an example ISS system constructed and operative in accordance with an embodiment of the present invention.

(124) The system typically allows changing parameters of the selected program. Options provided may include some or all of: Change Parameters, Analog Inputs, Digital I/O, Calibration, Manual Mode, Maintenance, and Screen Contrast.

(125) Programmable Cycle Parameters may include some or all of:

(126) TABLE-US-00001 Ster Temp 134.0 Ster Time 005.0 Dry Time 005.0 Vac Pulses 0001 End Temp 090.0 SterPressAdd 012.0 ATMPressure 100.0 Pulse Vac1 070.0 Pulse VacTI 0120 Pulse Press1 050.0 Pulse Vac2 030.0 Pulse Vac T2 0025 Pulse Press2 090.0 Pulse Vac3 030.0 Pulse Vac T3 0025 Pulse Press3 050.0
(in the above list, example values are shown).

(127) Analog Inputs may include some or all of:

(128) TABLE-US-00002 ChambPress 100.0 Gen Press 308.2 Seal Press 380.1 ElectrVacH 400.0 ElectrVacL 400.0 ElectDrain 400.0 CHamb.Angle 365.9 Chamb Temp 025.0 Drain Temp 025.0 ElectrGenH 400.0 ElectrGenL 400.0 Press 3 100.0 Press 10 100.0 ElectrChamb 400.0 Temp 8 025.0
(in the above list, example values are shown).
Digital inputs may for example include some or all of:
DoorCLosesSw
Gasket Touch
RingOpenSw
Piston2_In
Piston1_In
RingCloseSw2
RingCLoseSw3
RingCloseSw4
StartButton
StopButton
Up Button
Down Button
RingCloseSw
Exh.PosFixed
ExhPipeFixed
SafetyMainSw
Digital outputs may for example include some or all of:
Heaters
Chamb.Heater
Vacuum Pump
Water Pump
Main Locker
Motor Forward
Motor Back
Shred.Fast
Shred.Slow
DigOut5v09
Separator
Water.Chamb.
Steam.Chamb.
Connect Exh
Disrupt Exh
Clean Filter

(129) Calibration of analog inputs may be provided. In this case, typically, an ANALOG INPUTS screen is provided on which the names and real-time values of all-analog inputs which the system has are displayed. Also, a CALIBRATION screen is provided which may display chamber pressure and provide user input options such as but not limited to: Change GainOffset, Compute GainOffset and Restore Values. Compute Gain & Offset, for ChambPress 101.0, may for example yield the following:

(130) AH: 300.0 RH: 300.0 AL: 100.0 RL: 100.0

(131) The displayed lists may be browsed to select values to be calibrated.

(132) Available Calibration Operations may include:

(133) Change Gain & OffsetDirect typing of Gain and Offset values.

(134) Compute Gain & OffsetComputing Gain and Offset by two points.

(135) Restore ValuesRestore Gain and Offset values with factory defaults.

(136) Typically, computation of calibration values for the analog inputs (temperature, pressure) is performed digitally way and not by adjustment of trimmer pots (potentiometers). The temperature and pressure measuring circuits are typically designed with components having a 1% precision. The temperature circuit is typically linear and has an output of 100 mV2400 mV for a temperature range 20150 C. The pressure circuit is also linear and has an output of 100 mV2400 for a pressure range 0 to 400 kPa. The measuring at the A/D is void for values higher than 2400 mV or lower than 100 mV.

(137) Even though the precision of the components of the circuit is 1%, the accumulated error might reach 5%, therefore calibration is typically provided. The system is provided with non-erasable memory in which the offset and gain data of the sensors are stored. This data may be fed to the system through programming or through the machine.

(138) Calibration of temperature and pressure through the machine is now described. Programming calibration procedure may be generally the same. The machine is based on the computation of offset and gain from two points.

(139) FIG. 15, for example, is a graph of the actual and measured values which may result if the actual pressure is 100 kPa and the system measures and displays 90 kPa and if the actual pressure is 300 kPa and the system measures and displays 310 kPa. The calibration method enables these data to be introduced into the system in order to perform automatic correction of the OFFSET and GAIN. The method may include:

(140) 1. Browse the calibration list using the UP and DOWN keys and select the required:

(141) a. Read.H:Read high value of the analog input.

(142) b. Act. H:Actual high value of the analog input.

(143) c. Read.L:Read low value of the analog input.

(144) d. Act. L:Actual low value of the analog input.

(145) Typically, a GUI enables to view system's I/O, including analog inputs, digital inputs and digital outputs e.g. as described above. Suitable stage messages may be provided. For example, exhaust stage messages may include the following:

(146) Exh Water Cooling, signifying Cooling of the chamber through the water sprinkler.

(147) Exh Pressurizing, signifying pressurizing the chamber with compressed air before water removal.

(148) Exh Water Remove, signifying removing water from the chamber.

(149) Exh Finalizing, signifying that the machine is waiting for the safety pressure and temperature in the chamber.

(150) Other status messages, some or all of which may be displayed in order to monitor the device's status and cycle progress include:

(151) Ready: This message is displayed during the standby stage when the device is ready to start a new cycle.

(152) FAIL: This message is displayed during the standby stage when sterilization cycle fails.

(153) Door Open: This message is displayed during the standby stage when the door is open.

(154) Opening Door: This message is displayed during the standby stage when the door is on unlocking process.

(155) Water Inlet: This message is displayed during the process when the water inlets to the chamber.

(156) Steam On: This message is displayed during the heating stage when the system creates pressure by steam in the chamber.

(157) Heating to Ster.: This message is displayed during the heating stage when the system creates sterilization conditions.

(158) Sterilizing: This message is displayed during the sterilization stage.

(159) Exhaust: This message is displayed during the exhaust stage.

(160) Dry: This message is displayed during the dry stage.

(161) CYCLE END: This message is displayed during the standby stage when the sterilization cycle successfully ends.

(162) TEST ENDED: The message is displayed when the dynamic test is finished.

(163) Recommendations for waste segregation include working separately on non-infectious waste, infectious waste, highly non-infectious waste, and sharp particle waste.

(164) The sterilizer is equipped with two safety valves, located at the chamber and the steam generator.

(165) The valves in FIG. 11a are numbered according to its function, as indicated in the table of FIG. 14c.

(166) It is appreciated that terminology such as mandatory, required, need and must refer to implementation choices made within the context of a particular implementation or application described herewithin for clarity and are not intended to be limiting since in an alternative implantation, the same elements might be defined as not mandatory and not required or might even be eliminated altogether.

(167) It is appreciated that software components of the present invention including programs and data may, if desired, be implemented in ROM (read only memory) form including CD-ROMs, EPROMs and EEPROMs, or may be stored in any other suitable typically non-transitory computer-readable medium such as but not limited to disks of various kinds, cards of various kinds and RAMs. Components described herein as software may, alternatively, be implemented wholly or partly in hardware, if desired, using conventional techniques. Conversely, components described herein as hardware may, alternatively, be implemented wholly or partly in software, if desired, using conventional techniques.

(168) The scope of the present invention is not limited to structures and functions specifically described herein and is also intended to include devices which have the capacity to yield a structure, or perform a function, described herein, such that even though users of the device may not use the capacity, they are if they so desire able to modify the device to obtain the structure or function.

(169) Features of the present invention which are described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, features of the invention, including method steps, which are described for brevity in the context of a single embodiment or in a certain order may be provided separately or in any suitable subcombination or in a different order. e.g. is used herein in the sense of a specific example which is not intended to be limiting. The term main and the like as used herein refer to components of the system, some or all of which may be provided according to certain preferred embodiments.

(170) It is appreciated that in the description and drawings shown and described herein, functionalities described or illustrated as systems and sub-units thereof can also be provided as methods and steps therewithin, and functionalities described or illustrated as methods and steps therewithin can also be provided as systems and sub-units thereof. The scale used to illustrate various elements in the drawings is merely exemplary and/or appropriate for clarity of presentation and is not intended to be limiting.