Method of producing a gaseous hydrogen peroxide-containing sterilization fluid

• US 5,258,162 A
• Filed: 07/31/1992
• Issued: 11/02/1993
• Est. Priority Date: 11/07/1989
• Status: Expired due to Fees

• Current Assignee: Tetra Alfa Holdings, S.A.
• Original Assignee: Tetra Alfa Holdings, S.A.
• Inventors: Martensson, Lars, Smith, Goran, Andersson, Jan, Bjerborn, Thomas
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Trembley, T. A.
• Application Number:
  US07/921,594
• Time in Patent Office: 459 Days
• Field of Search: 422/27, 422/28, 422/29, 422/30, 422/32, 422/292, 422/297, 422/298, 422/300, 422/302, 422/304, 422/306, 53/425, 53/426
• US Class Current: 422/28
• CPC Class Codes: A61L 2/20 Gaseous substances, e.g. vapours
• CPC Class Codes: B65B 55/10 by liquids or gases

Abstract

A method of producing a gaseous, hydrogen peroxide-containing sterilization fluid displaying good, uniform sterilization properties is disclosed. The method includes vaporizing liquefied hydrogen peroxide by injecting the liquefied hydrogen peroxide intermittently in finely-divided form into an air current which serves as a vaporization agent, wherein the air current is kept at a constant or insignificantly varying elevated vaporization temperature. An even vaporization temperature of the air current is ensured because the air, prior to vaporization, is heated by heat exchange with a heating element having a large mass or thermal capacity and a large heat exchange surface area which is kept at the desired elevated temperature by regulated energy supplied to the heating element. During breaks in vaporization between the intermittent injection of the liquefied hydrogen peroxide, the heat exchange surface area is heated with the aid of heat stored in the heating element.

Claims

1. A method for conducting sterilization by an air stream containing hydrogen peroxide, comprising:

(a) heating a stream of ambient air in a preheater to a temperature of about 90°

C.;

(b) conducting the heated air stream intermittently through a first conduit and into a heat exchanger to increase the temperature of the heated air stream to a hydrogen peroxide vaporizing temperature;

(c) injecting liquefied hydrogen peroxide into the hydrogen peroxide-vaporizing air stream such that the hydrogen peroxide-vaporizing air stream vaporizes all of the liquefied hydrogen peroxide resulting in an air and vaporized hydrogen peroxide stream and supplying the air and vaporized hydrogen peroxide stream into a third conduit and then into a chamber for sterilizing the contents of the chamber; and

(d) reducing flow through said first conduit and conducting the heated air stream intermittently through a second conduit and into said third conduit and then into said chamber for drying the contents of the chamber, the flow of said heated air stream in said first conduit alternating with the flow of said heated air stream in said second conduit.

2. The method according to claim 1, including filtering the heated air stream in the second conduit, and wherein the heated air stream in the second conduit is at a temperature of about 90°

C.

3. The method according to claim 1, wherein said injecting step produces a concentration of hydrogen peroxide in the hydrogen peroxide-vaporizing air stream of about 25 grams of hydrogen peroxide per kilogram of air.

4. The method according to claim 1, wherein the intermittent flow of the heated air stream in the first conduit has a duration of about one second and the intermittent flow of the heated air stream in the second conduit has a duration of about 0.5 seconds.

5. An apparatus for sterilizing articles in a chamber, comprising:

(a) a first conduit for receiving ambient air and forming an air stream;

preheater means in said first conduit for heating said air stream;

(b) an outlet conduit for conducting said air stream into a chamber;

(c) a second conduit communicating between said preheater means and said outlet conduit, said second conduit including valve means for controlling flow through said second conduit;

(d) a third conduit communicating between said preheater means and said outlet conduit, said third conduit including valve means for controlling flow through said third conduit, said third conduit also including heat exchange means for heating the air stream to a temperature sufficient to vaporize liquefied hydrogen peroxide and vaporization means for vaporizing liquid hydrogen peroxide, and means, associated with the vaporization means, for injecting liquefied hydrogen peroxide into the vaporization means such that the heated air stream vaporizes all of the injected liquefied hydrogen peroxide; and

(e) means for alternately opening said valve means in said second conduit and in said third conduit, whereby the air stream containing hydrogen peroxide flows intermittently into said chamber to sterilize articles in said chamber, and whereby the air stream through the second conduit flows intermittently into said chamber to dry articles in the chamber.

6. The apparatus according to claim 5, wherein said heat exchange means including a heat exchange element having a large thermal capacity and large surface area.