Sterilizer with gas control

• US 5,641,455 A
• Filed: 12/22/1995
• Issued: 06/24/1997
• Est. Priority Date: 12/22/1995
• Status: Expired due to Term

• Current Assignee: 3M Company
• Original Assignee: 3M Company
• Inventors: Peters, David George, Rosenlund, Thomas Theodore
• Primary Examiner(s): Warden, Robert J.
• Assistant Examiner(s): MCKANE, ELIZABETH L
• Application Number:
  US08/577,196
• Time in Patent Office: 550 Days
• Field of Search: 422/3, 422/28, 422/33, 422/34, 422/110, 422/119, 422/292, 422/295
• US Class Current: 422/28
• CPC Class Codes: A61L 2/206 Ethylene oxide

Abstract

A sterilizer for sterilizing objects with biocidal gas which is designed to resist the deleterious effects of the biocidal gas. The invention provides a sterilizer having a sterilizing chamber for holding the objects to be sterilized, and a gas control system for manipulating the gaseous environment within the sterilizing chamber. The sterilizer has a vacuum control system, a vacuum line in fluid communication with the sterilizing chamber, a humidity sensor connected to that vacuum line at a point removed from or outside of the sterilizing chamber, and an isolation valve connected to the vacuum line at a point between the sterilizing chamber and the humidity sensor for temporarily isolating the humidity sensor from the sterilizing chamber. This arrangement assures that the humidity sensor received a sufficient sample for reading the adequacy of the humidification of the objects to be sterilized, while at the same time protecting it from the biocidal gas. In preferred embodiments, the sterilizer is provided with biocidal gas in disposable canisters intended to be positioned and locked inside the sterilizing chamber with the objects to be sterilized. At the appropriate time, the canister is punctured by a puncture apparatus. The preferred puncture apparatus has a metal bellows assembly that is particularly resistant to failure by chemical attack from the biocidal gas.

Claims

1. A sterilizer for sterilizing objects with biocidal gas, comprising:

a sterilizing chamber for receiving objects to be sterilized, and a control system for manipulating the gaseous environment within the sterilizing chamber, the control system comprising;

a vacuum control system which can be connected to a vacuum source for evacuating the sterilizing chamber,

a water control system which can be connected to a water source for injecting a selectable quantity of water into the sterilizing chamber, and

a biocidal gas control system which can be connected to a biocidal gas source for controlling the release of biocidal gas, wherein the vacuum control system comprises;

a vacuum line in fluid communication with the sterilizing chamber,

a humidity sensor connected to the vacuum line at a location removed from the sterilizing chamber for measuring the humidity of gas flowing from the sterilizing chamber through the vacuum line, and

an isolation valve connected to the vacuum line at a location between the sterilizing chamber and the humidity sensor for temporarily isolating the humidity sensor from the sterilizing chamber.

2. A sterilizer for sterilizing objects with biocidal gas according to claim 1 wherein the vacuum line comprises a main vacuum line in fluid communication with the sterilizing chamber, and a branch vacuum line attached to the main vacuum line, and wherein the humidity sensor is connected to branch vacuum line so that the isolation valve can activate to isolate the branch line to isolate the humidity sensor from the sterilizing chamber.

3. A method of sterilizing objects with biocidal gas, comprising the steps of:

(1) providing a sterilizing chamber for receiving objects to be sterilized;

(2) providing a vacuum line having two branches in fluid communication with the sterilizing chamber, one of the branches having a humidity sensor and an isolation valve between the humidity sensor and the sterilizing chamber;

(3) inserting objects to be sterilized within the sterilizing chamber and sealing the sterilizing chamber;

(4) drawing a partial vacuum within the sterilizing chamber through the vacuum line;

(5) injecting water into the sterilizing chamber,

(6) evaluating the humidification within the sterilizing chamber by drawing a sample of gas from the sterilizing chamber through the vacuum line and into contact with the humidity sensor;

(7) closing the isolation valve when the humidity sensor detects that the humidification within the sterilizing chamber has reached a pre-selected level; and

(8) releasing biocidal gas within the sterilizing chamber causing the objects to be sterilized.