Steam sterilization system for sterilizing medical waste

• US 7,815,851 B1
• Filed: 04/13/2006
• Issued: 10/19/2010
• Est. Priority Date: 04/13/2006
• Status: Expired due to Fees

• Current Assignee: Assured Waste Solutions, LLC
• Original Assignee: Robert W. Lewis
• Inventors: Lewis, Robert W.
• Primary Examiner(s): McKane; Elizabeth L
• Application Number:
  US11/403,670
• Time in Patent Office: 1,650 Days
• Field of Search: None
• US Class Current: 422/3
• CPC Class Codes: A61L 2/07 Steam
• CPC Class Codes: A61L 2/24 Apparatus using programmed or automatic operation
• CPC Class Codes: A61L 2202/122 Chambers for sterilisation

Abstract

An integrated sterilization and materials handling system for sterilizing and handling items such as medical waste, paper, or other things comprises a cart for carrying a removable bin for holding the items to be sterilized, and a sterilization chamber that receives the bin when it is removed from the cart. The various embodiments include a bin that is dumpable with the cart using existing dumping apparatus, a bin that pivots on the cart to permit dumping of the items from the bin by tilting the bin, and a bin used primarily in a dry heat sterilization process of the invention when sterilizing items that are not to be discarded after sterilization to facilitate loading and unloading of the bin. The system has thermal energy booster plates mounted in the sterilization chamber for providing dry radiant heat to the chamber, and the system may vary process times, process pressures, and process temperatures to predetermine settings that correlate to the weight of the items to be sterilized.

Claims

1. A method of sterilizing regulated medical waste using a steam autoclave that uses high temperature steam greater than 250 degrees Fahrenheit as an agent for sterilization, comprising the steps of

weighing the regulated medical waste to be sterilized to measure its weight,

selecting a waste type from a plurality of waste classifications that may be treated by the autoclave, the waste type selected pertaining to the medical waste type to be sterilized,

automatically varying process times, including residence time that the waste to be sterilized is exposed to steam in the autoclave, process temperatures, and process pressure, including vacuum for negative pressure and steam injection for positive pressure, to predetermined settings that correlate to the selected waste type and to the weight measured during the weighing step, and automatically varying duration of vacuum drawn and steam injection in the autoclave to predetermined settings that correlate to the selected waste type and to the weight measured during the weighing step, and

sterilizing the regulated medical waste to be sterilized with the autoclave using the predetermined settings that correlate to the selected waste type and to the weight measured during the weighing step.

2. The method of claim 1, the autoclave including a pressure vessel, the pressure vessel having a sterilization chamber for steam sterilization, the sterilizing step including

placing the medical waste contained in waste containment systems into the sterilization chamber of the autoclave,

displacing the air in the sterilization chamber with steam,

heating the sterilization chamber with the steam to an effective temperature for killing all airborne pathogens in the waste containment systems and maintaining the temperature in the sterilization chamber at or above the effective temperature until the airborne pathogens are killed,

drawing a vacuum in the sterilization chamber after the airborne pathogens in the containment systems have been killed,

introducing steam into the sterilization chamber again,

heating the sterilization chamber with the steam to an effective temperature to sterilize the medical waste and maintaining the temperature in the sterilization chamber at or above the effective temperature until the medical waste is sterilized, and

drawing a vacuum in the sterilization chamber after the medical waste has been sterilized to vaporize condensate.

3. The method of claim 1, the autoclave including a pressure vessel, the pressure vessel having a sterilization chamber for steam sterilization, wherein the sterilization step takes place in the sterilization chamber, and wherein a bin is used for holding the medical waste in the sterilization chamber, the bin having bin walls that form the bin, and further including the step of spraying cooling water from nozzles affixed inside the sterilization chamber on outer surfaces of bin walls for cooling the bin after sterilization.

4. The method of claim 1, wherein the sterilization step takes place in a sterilization chamber of the autoclave, and further including the step of providing steam generated dry radiant heat in the sterilization chamber to vaporize fluids present in the sterilization chamber on the medical waste after sterilization.

5. The method of claim 4,

the steam generated dry radiant heat being provided from a thermal energy booster plate mounted in the sterilization chamber, the thermal energy booster plate having a conduit formed therein for carrying steam to heat the plate to produce dry radiant heat to radiate from the plate.

6. The method of claim 1, the sterilization step including multiple times both drawing a vacuum in the sterilization chamber and introducing steam to the sterilization chamber.

7. The method of claim 1,

wherein the sterilization step takes place in a sterilization chamber of the autoclave, and

wherein a bin is used for holding the medical waste in the sterilization chamber, and

further including the steps of

inserting the bin into the sterilization chamber after the medical waste held in the bin has been sterilized and emptied from the bin,

providing steam generated dry radiant heat in the sterilization chamber to heat the bin,

spraying pressurized wash water from nozzles mounted in the sterilization chamber onto the bin to wash the bin,

after the spraying step is completed, drying the bin by continuing to provide steam generated dry radiant heat in the sterilization chamber, and

after the drying step is completed, discontinuing providing steam generated dry radiant heat in the sterilization chamber and removing the bin from the sterilization chamber for reuse.

8. A sterilization system, comprising

an autoclave, the autoclave having a sterilization chamber, the chamber having an interior, the chamber having an opening through which access to the interior of the chamber is obtained, and the chamber having the door mounted at the opening for sealingly closing the opening when closed,

a scale integrated with a control computer for weighing the items to be sterilized, and

a programmable logic controller controlled by the control computer, the programmable logic controller configured to manage sequential sterilization process steps and configure to automatically vary programmable logic controller set points including process times, including residence time that the waste to be sterilized is exposed to steam in the autoclave, process temperatures, process pressure, including vacuum for negative pressure and steam injection for positive pressure, and duration of vacuum drawn and steam injection in the autoclave, based upon predetermined settings that correlate to a waste type selected from a plurality of waste classifications for treatment by the autoclave that pertains to the medical waste type to be sterilized and to the weight measured by the scale.

9. The sterilization system of claim 8, further including

a bin for holding items to be sterilized, and

a water spraying assembly for cooling the bin after sterilization, the water spraying assembly having nozzles mounted in the interior of the chamber and aligned to spray cooling water on outer walls of the bin.

10. The sterilization system claim 8, further including

a thermal energy booster apparatus mounted in the sterilization chamber for providing steam generated dry radiant heat to the sterilization chamber, the thermal energy booster apparatus having a conduit formed therein for carrying steam to heat the thermal energy booster apparatus to produce dry radiant heat to radiate from the thermal energy booster apparatus.

11. A method of sterilizing things using an autoclave, comprising the steps of

weighing the things to be sterilized to measure their weight,

selecting a type from a plurality of types of things that may be treated by the autoclave, the type selected pertaining to the type of things to be sterilized,

automatically varying process times, process temperatures, and process pressures for sterilizing the things to be sterilized to predetermined settings that correlate to the selected type and to the weight measured during the weighing step, and

sterilizing the things to be sterilized with the autoclave using the predetermined settings that correlate to the selected type and to the weight measured during the weighing step.

12. The method of claim 11, the sterilizing step including

placing the things to be sterilized into a sterilization chamber of the autoclave,

displacing the air in the sterilization chamber with steam,

heating the sterilization chamber with the steam to an effective temperature for killing all airborne pathogens among the things to be sterilized and maintaining the temperature in the sterilization chamber at or above the effective temperature until the airborne pathogens are killed,

drawing a vacuum in the sterilization chamber after the airborne pathogens in the containment systems have been killed,

introducing steam into the sterilization chamber again,

heating the sterilization chamber with the steam to an effective temperature to sterilize the things to be sterilized and maintaining the temperature in the sterilization chamber at or above the effective temperature until the things to be sterilized are sterilized, and

drawing a vacuum in the sterilization chamber after the things to be sterilized have been sterilized to vaporize condensation.

13. The method of claim 12, wherein the sterilization step takes place in a sterilization chamber of the autoclave, and further including the step of providing steam generated dry radiant heat in the sterilization chamber to vaporize fluids present in the sterilization chamber.

14. The method of claim 13,

the steam generated dry radiant heat being provided from a thermal energy booster plate mounted in the sterilization chamber, the thermal energy booster plate having a conduit formed therein for carrying steam to heat the plate to produce dry radiant heat to radiate from the plate.

15. The method of claim 11, wherein the sterilization step takes place in a sterilization chamber of the autoclave, and wherein a bin is used for holding the things to be sterilized in the sterilization chamber, the bin having bin walls that form the bin, and further including the step of spraying cooling water from nozzles affixed inside the sterilization chamber on outer surfaces of bin walls for cooling the bin after sterilization.

16. The method of claim 11, wherein the sterilization step takes place in a sterilization chamber,

the sterilization step comprising heating the things to be sterilized with steam generated dry radiant heat to an effective temperature to sterilize the things to be sterilized and maintaining the temperature at or above the effective temperature until sterilization of the things to be sterilized has been accomplished, by providing thermal energy from a thermal booster apparatus positioned in the sterilization chamber, the thermal energy booster apparatus having a conduit formed therein for carrying steam to heat the thermal energy booster apparatus to produce dry radiant heat to radiate from the thermal energy booster apparatus.

17. A method of treatment for Regulated Medical Waste by an autoclave that is controlled by variable data inputs to a computer programmed to reset a programmable logic controller (PLC) for the distinctive waste characteristics of each individual Regulated Medical Waste load being treated, comprising the steps of

inputting data pertaining to the waste classification of the Regulated Medical Waste to be treated into the computer,

inputting data pertaining to the weight of the waste load of the Regulated Medical Waste being treated into the computer,

using the computer, setting the programmable logic controller (PLC) to predetermined settings that correlate to the data inputted pertaining to the waste classification of the individual Regulated Medical Waste load to be treated,

using the computer, setting the programmable logic controller (PLC) to predetermined settings that correlate to the data inputted pertaining to the weight of the individual Regulated Medical Waste load to be treated, and

treating the individual Regulated Medical Waste load to be treated in the autoclave using the predetermined settings that correlate to the data inputted pertaining to the waste classification of the individual Regulated Medical Waste load to be treated and that correlate to the data inputted pertaining to the weight of the waste load of the Regulated Medical Waste load to be treated to disinfect/sterilized the individual Regulated Medical Waste load,

the individual Regulated Medical Waste load treating step including using high temperature steam greater than 250 degrees Fahrenheit in the autoclave as an agent for disinfection/sterilization.

18. A method of sterilizing things using an autoclave, comprising the steps of

weighing the things be sterilized to measure their weight,

selecting a cycle of treatment by the autoclave from a plurality of cycles of treatment by the autoclave that pertains to the type of things to be sterilized,

automatically varying process times, process temperatures, and process pressures of the autoclave for sterilizing things to predetermined settings that correlate to the cycle of treatment selected that pertains to the type of things to be sterilized and to the weight measured during the weighing step, and

sterilizing the things to be sterilized with the autoclave using the predetermined settings that correlate to the cycle of treatment selected that pertains to the type of things to be sterilized and to the weight measured during the weighing step.

19. The method of claim 18, the sterilizing step including

placing the things to be sterilized into a sterilization chamber of the autoclave,

displacing the air in the sterilization chamber with steam,

heating the sterilization chamber with the steam to an effective temperature for killing all airborne pathogens among the waste and maintaining the temperature in the sterilization chamber at or above the effective temperature until the airborne pathogens are killed,

drawing a vacuum in the sterilization chamber after the airborne pathogens in the containment systems have been killed,

introducing steam into the sterilization chamber again,

heating the sterilization chamber with the steam to an effective temperature to sterilize the things to be sterilized and maintaining the temperature in the sterilization chamber at or above the effective temperature until the things to be sterilized are sterilized, and

drawing a vacuum in the sterilization chamber after the things to be sterilized have been sterilized.

20. The method of claim 18, wherein the sterilization step takes place in a sterilization chamber of the autoclave, and wherein a bin is used for holding the things to be sterilized in the sterilization chamber, the bin having bin walls that form the bin, and further including the step of spraying cooling water from nozzles affixed inside the sterilization chamber on outer surfaces of bin walls for cooling the bin after sterilization.

21. The method of claim 18, wherein the sterilization step takes place in a sterilization chamber of the autoclave, and further including the step of providing steam generated dry radiant heat in the sterilization chamber to vaporize fluids present in the sterilization chamber after sterilization.

22. The method of claim 18, the sterilization step including multiple times both drawing a vacuum in the sterilization chamber and introducing steam to the sterilization chamber.

23. The method of claim 18,

wherein the sterilization step takes place in a sterilization chamber of the autoclave, and

wherein a bin is used for holding the things to be sterilized in the sterilization chamber, and

further including the steps of

inserting the bin into the sterilization chamber after the things to be sterilized held in the bin have been sterilized and emptied from the bin,

providing steam generated dry radiant heat in the sterilization chamber to heat the bin,

spraying pressurized wash water from nozzles mounted in the sterilization chamber onto the bin to wash the bin,

after the spraying step is completed, drying the bin by continuing to provide steam generated dry radiant heat in the sterilization chamber, and

after the drying step is completed, discontinuing providing steam generated dry radiant heat in the sterilization chamber and removing the bin from the sterilization chamber for reuse.