Portable chemical sterilizer

• US 7,976,791 B2
• Filed: 06/10/2009
• Issued: 07/12/2011
• Est. Priority Date: 11/10/2004
• Status: Active Grant

• Current Assignee: The United States Of America As Represented By The Secretary Of The Army
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Kustin, Kenneth, Doona, Christopher, Taub, Irwin A., Curtin, Maria, Feeherry, Florence, Baer, David, McManus, Albert T., Kandlikar, Satish
• Primary Examiner(s): Conley; Sean E
• Assistant Examiner(s): YOO, REGINA M
• Application Number:
  US12/476,701
• Publication Number:
  US 20090263291A1
• Time in Patent Office: 762 Days
• Field of Search: 422/292, 422/295, 422/297, 422/299, 422/300, 422/28, 422/29, 422/37, 422/305
• US Class Current: 422/292
• CPC Class Codes: A01N 2300/00 Combinations or mixtures of active ingredients covered by classes A01N27/00 - A01N65/48 with other active or formulation relevant ingredients, e.g. specific carrier materials or surfactants, covered by classes A01N25/00 - A01N65/48
• CPC Class Codes: A01N 37/36 containing at least one carboxylic group or a thio analogue, or a derivative thereof, and a singly bound oxygen or sulfur atom attached to the same carbon skeleton, this oxygen or sulfur atom not being a member of a carboxylic group or of a thio analogue, or of a derivative thereof, e.g. hydroxy-carboxylic acids
• CPC Class Codes: A01N 43/08 with oxygen as the ring hetero atom
• CPC Class Codes: A01N 43/16 with oxygen as the ring hetero atom
• CPC Class Codes: A01N 59/00 Biocides, pest repellants or attractants, or plant growth regulators containing elements or inorganic compounds
• CPC Class Codes: A01N 59/02 Sulfur; Selenium; Tellurium; Compounds thereof
• CPC Class Codes: A01N 59/16 Heavy metals; Compounds thereof
• CPC Class Codes: A01N 59/20 Copper
• CPC Class Codes: A61L 2/186 Peroxide solutions
• CPC Class Codes: A61L 2/208 Hydrogen peroxide
• CPC Class Codes: A61L 2202/16 Mobile applications, e.g. portable devices, trailers, devices mounted on vehicles
• CPC Class Codes: C11D 3/0042 Reducing agents
• CPC Class Codes: C11D 3/046 Salts
• CPC Class Codes: C11D 3/1206 free metals, e.g. aluminium grit or flakes
• CPC Class Codes: C11D 3/2086 Hydroxy carboxylic acids-salts thereof
• CPC Class Codes: C11D 3/3947 Liquid compositions
• CPC Class Codes: C11D 3/3956 Liquid compositions
• CPC Class Codes: C11D 3/48 Medical, disinfecting agents, disinfecting, antibacterial, germicidal or antimicrobial compositions

Abstract

A portable, lightweight, easy-to-carry, reusable, durable, and environmentally-friendly assembly for sterilizing contaminated equipment using conditions of a chemical sterilant, heat, and humidity generated in situ without requiring external electricity, fuels, or other exogenous energy sources for operation. The carry assembly includes a plastic carry-case or insulated aluminum pressure vessel having an inner chamber for accepting microbiologically contaminated objects, a vessel disposed in the chamber for serving as a reaction chamber and/or boiler, a chemical combination which upon mixing generates at least minimally sufficient conditions of the sterilant, heat, and humidity to effect sterilization of the objects, and outlet valves mounted on the carry-case for controllably venting pressures above ambient air pressure.

Claims

1. An assembly for sterilizing of a plurality of microbiologically contaminated objects, using in situ generated chlorine dioxide sterilant, heat, and humidity, the assembly comprising:

a unit comprising a closable, portable, hand carried carry case weighing up to about 35 pounds and having an inner chamber for accepting microbiologically contaminated objects;

an interior vessel disposed in the inner chamber for serving as a reaction chamber, said vessel for receiving and combining dry chemical precursors with water, within the case, said vessel being adapted for rinsing and cleaning, independently from the case, for reusing the vessel on other contaminated objects;

a combination of dry chemical precursors which upon combining with water generates in situ biocidal sterilization agents, and subsequently generates at least minimally sufficient conditions of the chlorine dioxide sterilant, heat, and humidity to effect microbiological sterilization of the objects, said combination of dry chemicals excluding acids and consisting of iron-activated magnesium Mg(Fe), chlorite ion ClO₂⁻

as an oxidant, sulfite ion SO₃²⁻

as a reductant, and sodium hydrogen ascorbate ion AH⁻

as an effector, said sodium hydrogen ascorbate being in an amount less than a stoichiometric amount, and said combination of dry chemical precursors being combined with water causing a reaction by electron transfer, and not acidification, during sterilization, at neutral pH, for producing heat and humidity and chlorine dioxide in amounts sufficient to effect said sterilization, under which reaction by electron transfer the ascorbate initiates a reduction of chlorite by a transfer of an electron from chlorite to ascorbate for causing a release of heat, a decrease in solution pH, and a release of chlorine dioxide in heated gaseous and acqueous forms, said reaction between ascorbate and chlorite inducing chemical reaction between chlorite and sulfite for producing heat and increasing solution pH for generating heated chlorine dioxide at neutral pH for affecting said objects to expose any contaminating microorganisms to said chlorine dioxide and sterilizing said objects;

a pressure release outlet check valve mounted on said unit for automatically periodically controlling pressures at ambient during sterilization and venting pressures above ambient and releasing any heated gases and sterilant after sterilization, whereby said outlet check valve prevents accumulation of pressures above ambient air pressures in the inner chamber during a sterilization process cycle, and vents pressures above ambient and releases any heated gases and sterilant after sterilization of the objects for flushing said gases and sterilant from the unit for allowing access to said objects;

a dry gas scrubber, comprising porous sponge material, engrafted onto and with a protective framework of said outlet check valve, a reductant comprising sulfur ions being embedded in the sponge material, said scrubber, valve and framework not protruding beyond the unit, for absorbing any chlorine dioxide gas exiting the unit during any stage of a sterilization process, said gas scrubber for inactivating the chlorine dioxide gas passing through the scrubber, the chlorine dioxide being reduced by the ions for forming a reaction converting chlorine dioxide and the reductant to inert ionic chloride and sulfate, respectively; and

an inlet valve, being a filtered one way valve, mounted on said unit, for permitting incoming air to flow into the unit after sterilization, said incoming air being distributed within the unit and mixing with any gaseous products remaining in the unit, said incoming air increasing pressure from ambient to greater than ambient in the unit and thereby flushing any remaining gaseous products from the unit through the outlet valve after sterilization of the objects, said inlet valve preventing any gases from flowing out of the unit through the inlet valve, and said inlet valve having a filter for filtering incoming air and preventing introduction of contaminating air-borne particulate matter and microbiological contaminants to re-contaminate the sterilized objects, whereby the outlet check valve and the inlet valve cooperate to maintain ambient pressure during sterilization, to increase pressure, after sterilization, and to flush any gaseous products from the unit;

wherein the assembly, including the unit, vessel, combination of dry chemical precursors with water, outlet check valve and dry scrubber, and filtered inlet valve, is self-contained, reusable and is free of any external source of power for controllably generating sufficient amounts of chlorine dioxide, heat, and humidity to sterilize the contaminated objects, for preventing accumulation of pressures above ambient air pressures during sterilization, for increasing pressure after sterilization, and for venting and deactivating chemical reaction products from the unit.

2. The assembly in accordance with claim 1, wherein said unit comprises a generally rectangular-shaped bottom wall, four side walls respectively upstanding from side edges of said bottom wall, and a top wall pivotally mounted on one of said side walls and adapted to be moved between an open position and a closed position so as to define, in conjunction with said bottom wall and said side walls, the inner chamber, said vessel being placed in the inner chamber and adapted to receive said combination of dry chemical precursors for combining with water, and a support structure for receiving and supporting the contaminated objects, said outlet check valve and said dry gas scrubber, being mounted in at least one of said walls, and said filtered inlet valve being mounted in one of said walls, and wherein said filtered inlet valve is in communication with an air circulator tube, said tube being perforated and disposed within said chamber, and wherein the chemical combination comprises water, iron-activated magnesium, chlorite ion, sulfite ion, and hydrogen ascorbate ion.

3. The assembly in accordance with claim 1 and further comprising an air circulator tube in communication with said inlet valve and said chamber, said tube being perforated and disposed within the chamber in a manner, generally circular, for circulating incoming air throughout the unit and mixing said air with said any gaseous products for forming a mixture and increasing pressure inside the chamber, said mixture flowing out of said outlet check valve, said outlet check valve automatically opening and closing periodically for assuring said mixing and for flowing said mixture out of the unit.

4. The assembly in accordance with claim 3 wherein said inlet valve is connected to a portable air pump for flowing air into the unit and providing a flow of air into the chamber and acting in concert with operation of the outlet valve engrafted with the scrubber for flushing and removing sterilant gas from the chamber after a sterilization process is completed.

5. The assembly in accordance with claim 1 wherein said unit is insulated aluminum.

6. The assembly in accordance with claim 1 wherein said chemical combination comprises about 600 mL H₂0, 85 g Mg(Fe), 185 g NaClO₂, 126 g Na₂SO₃, and 50 g NaC₆H₇O₆.

7. The assembly in accordance with claim 1 wherein said unit is plastic.

8. The assembly in accordance with claim 1 wherein said reductant for the scrubber is selected from the group consisting of sulfite (SO₃²⁻

), dithionite (S₂O₅²⁻

), and thiosulfate (S₂O₃²⁻

).

9. The assembly in accordance with claim 1, wherein said combination of chemical precursors and water is varied in relative proportions of chemical components depending on size of unit in which sterilization occurs.

10. The assembly in accordance with claim 1, wherein said combination of chemical precursors and water is varied in relative proportions of chemical components depending on different characteristics of the combination of chemicals.

11. The assembly in accordance with claim 1, wherein a chlorine-containing oxidant is derived from any one of several salts having different counter ions.

12. The assembly in accordance with claim 11, wherein any one of several salts is selected from the group consisting of lithium, sodium, potassium, and calcium cations.

13. The assembly in accordance with claim 1, wherein a hydrogen ascorbate salt is an effector.

14. The assembly in accordance with claim 13, wherein said effector is selected from the group consisting of ionic conjugate base forms of ascorbic acid (ascorbate), erythorbic acid (erythorbate), tartaric acid (tartarate), and any of their respective ions.

15. The assembly in accordance with claim 1, wherein said scrubber consists of two layers of wire gauze sandwiching said porous sponge material, said sponge material being embedded with said reductant for inactivating chlorine dioxide gas exiting the unit.

16. The assembly in accordance with claim 15, wherein the reductant is sodium sulfite.