Process for cleaning, disinfecting, and sterilizing materials using the combination of dense phase gas and ultraviolet radiation

• US 5,996,155 A
• Filed: 07/24/1998
• Issued: 12/07/1999
• Est. Priority Date: 07/24/1998
• Status: Expired due to Term

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Chao, Sidney C., Beach, Robert W., Sorbo, Nelson W., Purer, Edna M.
• Primary Examiner(s): Coe, Philip R.
• Application Number:
  US09/122,390
• Time in Patent Office: 501 Days
• Field of Search: 134/1, 134/1.3, 134/2, 134/10, 134/12, 134/40, 134/902, 8/158, 8/159, 8/137, 8/142, 68/18 R, 68/13 R, 210/634, 210/774, 210/805, 210/806
• US Class Current: 8/158
• CPC Class Codes: A61L 2/10 Ultraviolet radiation

Abstract

A process is provided for cleaning, disinfecting, and sterilizing substrates comprising the steps of: (a) placing the contaminated substrate in a cleaning vessel; (b) contacting the contaminated substrate with dense phase carbon dioxide in liquid form; (c) subjecting the substrate and the dense phase carbon dioxide to ultraviolet radiation having a wavelength within the range of about 180 to 300 nm for a duration and intensity sufficient to produce a photochemical reaction capable of destroying the DNA of microorganisms on the substrate; (d) substantially simultaneously subjecting at least the dense phase carbon dioxide to agitation; and (e) removing the dense phase carbon dioxide from the cleaning vessel and thereby transporting the contaminants from the substrate such that the substrate is cleaned and, in the case of contaminated garments, disinfected or, in the case of medical and dental instrumentation, sterilized. Substantially simultaneously with the UV exposure and agitation, the substrates are also subjected to an oxidizing sterilant, such as H₂ O₂.

Claims

1. A process for sterilizing fabrics and garments and removing soils therefrom, including microorganisms comprising organic molecular bonds in the form of DNA, said process comprising the steps of:

(a) placing at least one said garment containing said soils in a cleaning and disinfecting vessel;

(b) contacting said at least one garment containing said soils with dense phase carbon dioxide in liquid form;

(c) subjecting said at least one garment and said dense phase carbon dioxide to ultraviolet radiation having a wavelength within the range of about 180 to 300 nm for a duration and intensity sufficient to produce a photochemical reaction that breaks said organic molecular bonds, thereby destroying said DNA and resulting in fragmented biological contaminants;

(d) substantially simultaneously subjecting said at least one garment to mechanical agitation; and

(e) removing said dense phase carbon dioxide from said cleaning and disinfection vessel and thereby transporting said soils, including said fragmented biological contaminants, from each said garment such that each said garment is cleaned and disinfected.

2. The process of claim 1 wherein said mechanical agitation is performed by a set of fluid jet manifolds to mechanically agitate said garment and said dense phase carbon dioxide.

3. The process of claim 1 wherein said radiation has a wavelength within the range of about 253 to 254 nm.

4. The process of claim 1 wherein step (b) further comprises contacting said at least one garment with a sterilizing agent to enhance destruction of said microorganisms.

5. The process of claim 4 wherein said sterilizing agent is an oxidizing agent selected from the group consisting of an oxygen-containing compound and a hydrogen-containing compound.

6. The process of claim 5 wherein said sterilizing agent is selected from the group consisting of hydrogen peroxide and ozone.

7. The process of claim 6 wherein said hydrogen peroxide is mixed with said dense phase gas prior to introduction into said cleaning and disinfecting vessel.

8. The process of claim 1 wherein said biological contaminant is selected from a group consisting of bacteria and spores.