Microwave-assisted steam sterilization of dental and surgical instruments

• US 20040112894A1
• Filed: 09/29/2003
• Published: 06/17/2004
• Est. Priority Date: 02/08/2002
• Status: Active Grant

• Current Assignee: Ecofriend Technologies, Inc.
• Original Assignee: Ecofriend Technologies, Inc.
• Inventors: Varma, Ravi
• Granted Patent: US 6,900,421 B2
• Time in Patent Office: Days
• US Class Current: 219/679
• CPC Class Codes: A61C 19/002 Cleaning devices specially adapted for dental instruments disinfecting A61L2/00; cleaning in general B08B
• CPC Class Codes: A61L 2/07 Steam
• CPC Class Codes: A61L 2/12 Microwaves
• CPC Class Codes: H05B 6/806 for laboratory use

Abstract

A surgical and dental instrument sterilizer is described. Liquid water is rapidly vaporized by microwave heating and steam is generated to attain a steam pressure of approximately 47 psi and a temperature of approximately 135° C. in the region of the articles to be sterilized. Micron-size water-droplets are intermittently sprayed onto the articles which are arranged on a tray, from both the top and from underneath thereof so as to thoroughly wet the surfaces. A 30-90 s duration of droplet spray is followed by pulsed microwave irradiation of the top and underneath surfaces for a similar period, as an example; this is followed by a plurality of spray/microwave cycles. Sterilizing conditions in the sterilizer chamber are maintained in the presence of the water spray/microwave flashing cycles since introducing small aliquots of water will not affect the desired sterilizing condition provided by superheated steam augmented by microwave radiation necessary to kill microbes including spores; however arcing from metal instruments when subjected to microwave radiation is substantially reduced.

Claims

1. A sterilization apparatus comprising in combination:

(a) a sealed first chamber capable of withstanding internal pressure and vacuum and having a sealable opening for introducing and removing articles to be sterilized;

(b) at least one tray disposed within said first chamber for holding items to be sterilized;

(c) a first microwave radiation generator;

(d) a first waveguide for directing microwave radiation generated by said first microwave radiation generator onto the articles to be sterilized;

(e) a sprayer for directing droplets of water onto the articles to be sterilized;

(f) means for generating steam at greater than one atmosphere of pressure and for introducing the steam into said first chamber;

(g) a pump for evacuating said first chamber before the steam is introduced thereto and for removing the steam after the sterilization process is completed; and

(h) means for detecting arcing in said first chamber and for shutting down said first microwave radiation generator in response thereto.

2. The sterilization apparatus as described in claim 1, further comprising a filter capable of removing pathogens, and means for venting said sealed chamber through said filter.

3. The sterilization apparatus as described in claim 2, wherein said filter comprises a HEPA filter.