Multiple flashpoint vaporization system

• US 6,077,480 A
• Filed: 06/19/1997
• Issued: 06/20/2000
• Est. Priority Date: 06/19/1997
• Status: Expired due to Term

• Current Assignee: Steris Corporation
• Original Assignee: Steris Corporation
• Inventors: Geist, Stephen G., Edwards, Steven J., Steen, Paul A.
• Primary Examiner(s): McKane, Elizabeth
• Assistant Examiner(s): Moazzam, Fariborz
• Application Number:
  US08/878,539
• Time in Patent Office: 1,097 Days
• Field of Search: 422/27, 422/306, 422/28, 422/305, 422/3, 422/29, 422/105, 422/108, 422/110, 422/119, 422/292, 422/298
• US Class Current: 422/28
• CPC Class Codes: A61L 2/208 Hydrogen peroxide
• CPC Class Codes: A61L 2/24 Apparatus using programmed or automatic operation
• CPC Class Codes: A61L 2202/15 Biocide distribution means, e.g. nozzles, pumps, manifolds, fans, baffles, sprayers

Abstract

A multiple flashpoint vaporization system rapidly sterilizes large enclosures. A plurality of vaporizers (10) inject hydrogen peroxide vapor into streams of carrier gas supplied by a generator (20). Supply lines (30) transport the mixture of carrier gas and hydrogen peroxide vapor to a plurality of regions of an enclosure (32). Monitors (52) monitor hydrogen peroxide vapor concentration or other conditions in each region of the enclosure. A control system (50) adjusts the hydrogen peroxide vapor supply rate in response to the corresponding monitored conditions.

Claims

1. A hydrogen peroxide sterilization system comprising:

(a) a plurality of vaporizers which independently inject vaporized hydrogen peroxide into a carrier gas at differently adjustable rates, each vaporizer including a separate liquid hydrogen peroxide regulator for simultaneously, variably, and independently controlling a rate of injection of hydrogen peroxide into the vaporizer;

(b) a carrier gas supply for supplying a flow of the carrier gas to the vaporizers;

(c) at least one supply line for transporting the hydrogen peroxide vapor and the carrier gas from each vaporizer to different regions of an enclosure to be sterilized; and

a control system for controlling each of the vaporizers to adjust independently the rate at which each vaporizer injects vaporized hydrogen peroxide into the carrier gas so as to provide each of the regions with a selected concentration of hydrogen peroxide vapor.

2. The system as set forth in claim 1, wherein each vaporizer further includes a carrier gas flow regulator for separately controlling a flow rate of carrier gas to the vaporizer to regulate a rate of hydrogen peroxide vapor production.

3. A hydrogen peroxide sterilization system comprising:

(a) a plurality of vaporizers, each of the vaporizers independently injecting vaporized hydrogen peroxide into a carrier gas at an independently regulated variable rate;

(b) a carrier gas generator for supplying a flow of the carrier gas to the vaporizers; and

,

(c) at least one supply line for each vaporizer for transporting the hydrogen peroxide vapor and the carrier gas from each vaporizer to different regions of an enclosure to be sterilized, each of the vaporizers supplying hydrogen peroxide vapor to a different region of the enclosure;

(d) a plurality of monitors for detecting conditions in each of the different regions of the enclosure; and

(e) a control system for controlling each of the vaporizers to adjust independently the rate at which each vaporizer injects vaporized hydrogen peroxide into the carrier gas in accordance with the detected conditions in the different regions.

4. A hydrogen peroxide sterilization system comprising:

(a) a plurality of vaporizers for injecting hydrogen peroxide vapor into a carrier gas;

(b) a carrier gas generator for supplying a flow of carrier gas to the vaporizers;

(c) at least one supply line for transporting the hydrogen peroxide vapor and the carrier gas from each vaporizer to different regions of an enclosure to be sterilized, each of the vaporizers supplying hydrogen peroxide vapor to at least one of the different regions of the enclosure;

d) a plurality of monitors for detecting conditions in each of the different regions of the enclosure; and

,

e) a control system for independently regulating a rate at which hydrogen peroxide vapor is supplied by each vaporizer in accordance with the detected conditions in each region of the enclosure.

5. The system as set forth in claim 4, wherein the control system includes a comparator for comparing the enclosure condition signals from the monitors with reference values to determine a deviation therebetween.

6. The system as set forth in claim 5, wherein the control system further includes a processor for addressing a preprogrammed look-up table in accordance with the deviations determined by the comparator and retrieving vaporizer adjustments values therefrom.

7. The system as set forth in claim 6, wherein the vaporizer adjustment values include a liquid hydrogen peroxide adjustment value and a carrier gas adjustment value and wherein each vaporizer includes:

a liquid hydrogen peroxide regulator for regulating a supply rate of liquid hydrogen peroxide to the vaporizer, the processor controlling the liquid hydrogen peroxide regulator in accordance with the hydrogen peroxide adjustment value retrieved from the look-up table; and

,

a carrier gas regulator for regulating a supply rate of the carrier gas to the vaporizer, the processor controlling the liquid hydrogen peroxide regulator in accordance with the carrier gas adjustment value from the look-up table.

8. A method for supplying vaporized hydrogen peroxide to an enclosure comprising:

at a first site, vaporizing a liquid solution of hydrogen peroxide to form hydrogen peroxide vapor at a first rate of vaporization;

at a second site, vaporizing a liquid solution of hydrogen peroxide to form hydrogen peroxide vapor at a second rate of vaporization which is independent of the first rate;

providing streams of carrier gas to the first and second sites;

entraining the hydrogen peroxide vapor into the streams of carrier gas at the first and second sites;

independently transporting the hydrogen peroxide vapor and carrier gas from the first and second sites to first and second regions of the enclosure; and

,

independently regulating the first and second rates of vaporization at the first and second sites and entraining hydrogen peroxide vapor into the streams of carrier gas.

9. The method as set forth in claim 8, further including:

holding the hydrogen peroxide vapor within the enclosure until sterilization is achieved.

10. The method as set forth in claim 8, further including drawing a vacuum within the enclosure prior to sterilization.

11. The method as set forth in claim 8, further including monitoring conditions in the first and second regions of the enclosure.

12. A method for supplying vaporized hydrogen peroxide to an enclosure comprising:

at a first site, vaporizing a liquid solution of hydrogen peroxide to form hydrogen peroxide vapor;

at a second site, vaporizing a liquid solution of hydrogen peroxide to form hydrogen peroxide vapor;

providing streams of carrier gas to the first and second sites;

entraining the hydrogen peroxide vapor into the streams of carrier gas at the first and second sites;

independently transporting the hydrogen peroxide vapor and carrier gas from the first and second sites to first and second regions of the enclosure;

monitoring conditions in the first and second regions of the enclosure;

determining deviations of the monitored conditions in each region from preselected conditions; and

,

independently regulating (i) a first variable rate at which the liquid hydrogen peroxide solution is vaporized and entrained in the carrier gas at the first site in accordance with the determined deviations in the first region and (ii) a second variable rate at which liquid hydrogen peroxide solution is vaporized and entrained in the carrier gas at the second site in accordance with the determined deviations in the second region.