Sterilization apparatus and method for multicomponent sterilant

• US 5,556,607 A
• Filed: 09/19/1995
• Issued: 09/17/1996
• Est. Priority Date: 03/13/1992
• Status: Expired due to Term

• Current Assignee: American Sterilizer Company (Steris Corporation)
• Original Assignee: American Sterilizer Company (Steris Corporation)
• Inventors: Childers, Robert W., Mielnik, Thaddeus J., Klobusnik, Kenneth J., Rickloff, James R.
• Primary Examiner(s): Warden, Robert
• Assistant Examiner(s): TRAN, HIEN THI
• Application Number:
  US08/530,577
• Time in Patent Office: 364 Days
• Field of Search: 422/26-28, 422/32-33, 422/292, 422/295, 422/300, 422/301, 422/905, 134/88-89, 134/170, 134/92, 134/166 R, 134/169 R, 433/104, 433/114, 433/132
• US Class Current: 422/300
• CPC Class Codes: A61C 1/0076 Sterilising operating fluids or fluid supply elements such as supply lines, filters sterilisation of liquid substances in general A61L2/18
• CPC Class Codes: A61C 19/002 Cleaning devices specially adapted for dental instruments disinfecting A61L2/00; cleaning in general B08B
• CPC Class Codes: A61L 2/20 Gaseous substances, e.g. vapours
• CPC Class Codes: A61L 2/208 Hydrogen peroxide
• CPC Class Codes: A61L 2/24 Apparatus using programmed or automatic operation
• CPC Class Codes: A61L 2202/122 Chambers for sterilisation
• CPC Class Codes: A61L 2202/24 Medical instruments, e.g. endoscopes, catheters, sharps

Abstract

The present invention provides a sterilization process particularly well suited for sterilizing instruments and other devices having long narrow lumens. Apparatus in which the process can be practiced is also provided. The process uses a multicomponent sterilant vapor wherein one component is water. The lumened instruments are fluidly connected to the exhaust manifold of the sterilizer. A deep vacuum is drawn in the sterilization chamber followed by the injection of pulses of the sterilant vapor until a higher, but still subatmospheric pressure level is reached. When the pressure level reaches a predetermined subatmospheric level, a flow-through sterilization phase begins. It includes successive alternating periods of sterilant flow and the discontinuance of such flow. During sterilant flow periods, there are sterilant injection pulses where the sterilant flows through the chamber and the lumened instruments to exhaust. Each such flow period is followed by a hold period. Following the sterilization phase, there are one or more aeration steps to remove sterilant from the chamber.

Claims

1. Apparatus for sterilizing items having at least two open ends and a fluid flow path between the open ends comprising:

a sterilization chamber having an inlet port and an exhaust port;

manifold means fluidly coupled to either the inlet port or the exhaust port and having a plurality of seats, each seat for fluid connection to fluid flow paths of one item;

means for creating a negative pressure differential downstream of the exhaust port;

a source of liquid sterilant;

means for vaporizing the liquid sterilant;

valve means intermediate the source of liquid sterilant and the vaporizing means for pulsing successive increments of liquid sterilant into the vaporizing means;

fluid connection means for fluidly connecting the source of liquid sterilant, the valve means, the vaporizing means and the chamber;

an air flow path through the vaporizing means and at least that portion of the fluid connection means passing from the vaporizing means to the chamber;

means for opening the exhaust port to flow the sterilant vapor and air through the inlet port and out of the chamber through the outlet port for a first period of time while maintaining the chamber pressure at a subatmospheric predetermined level, and for closing the exhaust port to stop the flow of sterilant vapor and air into and out of the chamber for a second period of time while maintaining the chamber pressure at said predetermined subatmospheric pressure; and

means for successively repeating in an alternating fashion the flowing and the stopping of the flow of sterilant vapor and air into and out of the chamber a plurality of times while maintaining the chamber pressure at said predetermined subatmospheric pressure.

2. The apparatus recited in claim 1 further comprising means for converting the sterilant vapor into constituents thereof suitable for disposal, said converting means being fluidly connected to the exhaust port of the chamber downstream of the means for creating negative pressure.

3. The apparatus recited in claim 1 wherein said chamber is a freeze dryer.

4. The apparatus recited in claim 1 wherein the inlet and exhaust ports of the chamber are constructed for releasable fluid connection to at least one removable member, said removable member being constructed to hold said items during a sterilization process so that said items are sterilized within said removable member when subjected to the sterilization process.

5. The apparatus recited in claim 4 wherein the manifold means are positioned in the at least one removable member for fluidly connecting said items to either said inlet or said exhaust ports such that sterilant vapor will flow through the fluid flow paths of the items during the sterilization process.

6. The apparatus recited in claim 4 wherein the removable member comprises first and second extension ports and wherein the inlet port and the exhaust port of the chamber each define a channel for fluid connection to the first and second extension ports, said channel housing a receiving member for receiving one of the first or second extension ports, a blocking member and an actuation member operatively connecting the receiving and blocking member and structured for slidable axial movement through the length of the channel;

means for limiting the travel of said actuation member within the channel; and

a bypass conduit fluidly joining the inlet channel and the exhaust channel, wherein when the first and second extension ports are inserted into the receiving members of each channel, each receiving member slides along a portion of each channel to effect the movement of each blocking member from a first position wherein the bypass conduit is open to a second position wherein the bypass conduit is closed.