Liquid carbon dioxide cleaning using agitation enhancements at low temperature

• US 6,264,753 B1
• Filed: 07/07/2000
• Issued: 07/24/2001
• Est. Priority Date: 01/07/1998
• Status: Expired due to Term

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Chao, Sidney C., Purer, Edna M., Sorbo, Nelson W.
• Primary Examiner(s): Carrillo, Sharidan
• Application Number:
  US09/611,454
• Time in Patent Office: 382 Days
• Field of Search: 134/1, 134/1.3, 134/2, 134/10, 134/13, 134/32, 134/34, 134/35, 134/40, 134/198, 134/199, 134/200, 134/902, 210/748
• US Class Current: 134/1
• CPC Class Codes: B01F 23/4111 using vibrations
• CPC Class Codes: B08B 3/12 by sonic or ultrasonic vibrations washing or rinsing machines for crockery or tableware using sonic or ultrasonic waves A47L15/13; of natural teeth, of prostheses using ultrasonic techniques similar to those used for natural teeth A61C17/20; application of ultrasonic vibrations to chemical, physical or physico-chemical processes in general B01J19/10
• CPC Class Codes: B08B 7/0021 by liquid gases or supercritical fluids
• CPC Class Codes: C23G 5/00 Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents
• CPC Class Codes: D06B 13/00 Treatment of textile materials with liquids, gases or vapours with aid of vibration
• CPC Class Codes: D06B 19/00 Treatment of textile materials by liquids, gases or vapours, not provided for in groups D06B1/00 - D06B17/00
• CPC Class Codes: D06F 43/00 Dry-cleaning apparatus or methods using volatile solvents D06F9/00 - D06F41/00 take precedence
• CPC Class Codes: Y10S 134/902 Semiconductor wafer

Abstract

A cleaning system and method utilizing sonic whistle and other agitation methods to enhance the soil removal and mass transport capacity of the liquid carbon dioxide at low process temperatures. Agitation devices disposed in or couple to a cleaning chamber, and cause the liquid carbon dioxide to ultrasonically emulsify and disperse non-miscible liquids or insoluble solids, such as remove low solubility oils and greases. Cleaning is accomplished at temperatures between −68° F. and 32° F., and the temperature of the liquid carbon dioxide is typically below 32° F.

Claims

1. A liquid carbon dioxide cleaning method embodied in a system having a cleaning chamber, said cleaning method comprising the steps of:

providing a cleaning chamber;

disposing vigorous agitation apparatus within the cleaning chamber;

introducing liquid carbon dioxide from a storage tank to the cleaning chamber through said vigorous agitation apparatus;

disposing a medical device in the cleaning chamber having one or more surfaces on which bio-burden is disposed; and

forcing the liquid carbon dioxide out of the vigorous agitation apparatus at a temperature that is below 32°

F. to solidify the bio-burden disposed on the one or more surfaces and remove the bio-burden from the one or more surfaces, and disperse and suspend the bio-burden in the liquid carbon dioxide for transport and removal from the cleaning chamber; and

removing the medical device from the cleaning chamber.

2. The cleaning method of claim 1, wherein the temperature of the liquid carbon dioxide is below 32°

F. and above −

68°

F.