Sterilization system and method and orifice inlet control apparatus therefor

Abstract

A chemical vapor sterilization process is enhanced by concentrating a germicide via exploitation of the difference between the vapor pressures of the germicide and its solvent. A diffusion restriction can be placed into the diffusion path to assist this process and the path then opened to provide rapid diffusion of the thus concentrated germicide. The path through the diffusion restriction can be closed to allow the pressure in a sterilization chamber to be lowered prior to receiving the concentrated germicide.

1 - 18 . (canceled) 
     
     
         19 . A method of sterilizing an article, comprising:
 providing a sterilant solution which comprises a sterilant and a solvent;   vaporizing the sterilant solution in a vaporizer;   placing the vaporizer into fluid communication with a sterilization chamber through a diffusion restriction, the sterilization chamber being at a lower pressure than the vaporizer;   increasing the ratio of sterilant to solvent by preferentially drawing a vapor phase of the solvent out of the vaporizer through the diffusion restriction and exhausting at least a portion of the solvent out of the sterilization chamber then isolating the vaporizer from the sterilization chamber and lowering the pressure in the sterilization chamber to a predetermined pressure selected to enhance diffusion of the vaporized sterilant into diffusion restricted areas of the article; and   placing the vaporizer into open fluid communication with the sterilization chamber and diffusing vaporized sterilant into the sterilization chamber and into contact with the article.   
     
     
         20 . The method according to  claim 19  wherein the sterilant is hydrogen peroxide and the solvent is water. 
     
     
         21 . The method according to  claim 19  wherein the step of placing the vaporizer into open fluid communication with the sterilization chamber comprises opening a valve between the vaporizer and the sterilization chamber. 
     
     
         22 . The method according to  claim 19 , wherein increasing the ratio of sterilant to solvent occurs in the vaporizer. 
     
     
         23 . The method according to  claim 19  wherein the step of placing the vaporizer into fluid communication with the sterilization chamber through a diffusion restriction comprises interposing an orifice between the vaporizer and the sterilization chamber. 
     
     
         24 . The method according to  claim 19 , further comprising the step of having a cleaning needle penetrate the orifice during the step of isolating the vaporizer from the sterilization chamber. 
     
     
         25 . A method of sterilizing an article, comprising:
 vaporizing the sterilant solution comprising a sterilant and a solvent;   placing the vaporizer into fluid communication with a sterilization chamber through a diffusion restriction, the sterilization chamber being at a lower pressure than the vaporizer;   increasing the ratio of sterilant to solvent by preferentially drawing a vapor phase of the solvent out of the vaporizer through the diffusion restriction and exhausting at least a portion of the solvent out of the sterilization chamber then isolating the vaporizer from the sterilization chamber and lowering the pressure in the sterilization chamber to enhance diffusion of the vaporized sterilant into diffusion restricted areas of the article; and   placing the vaporizer into open fluid communication with the sterilization chamber and diffusing vaporized sterilant into the sterilization chamber and into contact with the article.   
     
     
         26 . The method according to  claim 25  wherein the sterilant is hydrogen peroxide and the solvent is water. 
     
     
         27 . The method according to  claim 25  wherein the step of placing the vaporizer into open fluid communication with the sterilization chamber comprises opening a valve between the vaporizer and the sterilization chamber. 
     
     
         28 . The method according to  claim 25 , wherein increasing the ratio of sterilant to solvent occurs in the vaporizer. 
     
     
         29 . The method according to  claim 25 , wherein lowering the pressure in the sterilization chamber occurs to a predetermined pressure selected to enhance diffusion of the vaporized sterilant into diffusion restricted areas of the article. 
     
     
         30 . The method according to  claim 25 , wherein the step of placing the vaporizer into fluid communication with the sterilization chamber through a diffusion restriction comprises interposing an orifice between the vaporizer and the sterilization chamber. 
     
     
         31 . The method according to  claim 25 , further comprising the step of having a cleaning needle penetrate the orifice during the step of isolating the vaporizer from the sterilization chamber. 
     
     
         32 . A sterilization system comprising:
 a sterilization chamber;   a vacuum pump connected to the sterilization chamber; and   a vaporizer connected to the sterilization chamber, the vaporizer comprising:   an enclosure;   a first outlet path from the enclosure into the chamber, the first outlet path being restricted by a diffusion restriction and a first valve in the first outlet path;   a second outlet path from the enclosure into the chamber and a second valve in the second outlet path, whereby the enclosure can be placed into fluid communication with the sterilization chamber unimpeded by the diffusion restriction; and   providing a controller for controlling a sterilization process, the controller being programmed to include the following process steps:
 placing the vaporizer into fluid communication with the sterilization chamber solely through the diffusion restriction; 
 vaporizing a sterilant solution in the vaporizer; 
 when the vaporizing is substantially complete closing the first valve and lowering the pressure within the sterilization chamber. 
   
     
     
         33 . The sterilization system according to  claim 32 , wherein the diffusion restriction comprises an orifice plate having an orifice therethrough. 
     
     
         34 . The sterilization system according to  claim 32 , wherein the orifice is between 1 mm and 3 mm in diameter.