Porous load vapor sterilization cycle
First Claim
1. A method of increasing the temperature and pressure within a sealable chamber wherein a porous load is disposed for processing and from both of which noncondensable gases have been substantially removed comprising:
- after sealing said chamber, subjecting said chamber to a plurality of pressurization steps wherein a condensable vapor having transferable latent heat is so injected into said chamber that (a) said plurality of pressurization steps are sufficient to so gradually elevate the temperature and pressure within said chamber to a predetermined temperature and pressure effective for processing said porous load that the opportunity for substantially surpassing said predetermined temperature is substantially eliminated, and (b) said plurality of pressurization steps are sufficient to permit such penetration of said porous load by said vapor that said porous load reaches a general temperature equilibrium with said vapor in said chamber at about the same time as said chamber reaches said predetermined temperature to avoid superheating said chamber relative to said porous load;
each said pressurization step including a pressure rise during which said vapor is injected into said chamber followed by a pressure plateau, greater than the previous pressure plateau, during which said chamber is isolated and said vapor is not injected into said chamber to permit said vapor injected during said pressure rise to penetrate said porous load to displace noncondensable gases and to permit said chamber and said porous load temperatures to stabilize.
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Accused Products
Abstract
A steam sterilization cycle having a conditioning stage, a sterilizing stage, a drying stage and an air admission stage which provides maximum removal of entrapped air from full or partial porous loads. The conditioning stage includes a plurality of pressure/vacuum pulses. The final vacuum pulses are deeper than the initial pulses. The sterilizing stage includes a diffusion dwell come-up which gradually increases the temperature and pressure of the chamber to the predetermined sterilization temperature by a sequence of pressure rises followed by pressure plateaus which permit substantially complete steam penetration of the load and substantial equalization of the actual load temperature and the temperature sensed by the sterilizer controls and substantially eliminates superheating the chamber. The cycle may also include a step for detecting and reacting to unacceptable levels of noncondensable gas present in the chamber during the sterilization stage.
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Citations
12 Claims
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1. A method of increasing the temperature and pressure within a sealable chamber wherein a porous load is disposed for processing and from both of which noncondensable gases have been substantially removed comprising:
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after sealing said chamber, subjecting said chamber to a plurality of pressurization steps wherein a condensable vapor having transferable latent heat is so injected into said chamber that (a) said plurality of pressurization steps are sufficient to so gradually elevate the temperature and pressure within said chamber to a predetermined temperature and pressure effective for processing said porous load that the opportunity for substantially surpassing said predetermined temperature is substantially eliminated, and (b) said plurality of pressurization steps are sufficient to permit such penetration of said porous load by said vapor that said porous load reaches a general temperature equilibrium with said vapor in said chamber at about the same time as said chamber reaches said predetermined temperature to avoid superheating said chamber relative to said porous load; each said pressurization step including a pressure rise during which said vapor is injected into said chamber followed by a pressure plateau, greater than the previous pressure plateau, during which said chamber is isolated and said vapor is not injected into said chamber to permit said vapor injected during said pressure rise to penetrate said porous load to displace noncondensable gases and to permit said chamber and said porous load temperatures to stabilize. - View Dependent Claims (2, 3, 4, 5)
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6. In a method for sterilizing porous loads in a sterilizer having a sealable pressure chamber and associated piping wherein a condensable vapor having transferable latent heat is employed as a sterilizing agent, said method having at least a conditioning step during which noncondensable gases are removed from said chamber and said load, followed by a sterilization step an improvement in said sterilization stem comprising:
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subjecting said chamber to a plurality of pressurization steps wherein said vapor is so injected into said chamber that (a) said plurality of pressurization steps are sufficient to so gradually elevate the temperature and pressure effective for sterilizing said porous load that the opportunity for substantially surpassing said predetermined temperature is substantially eliminated and (b) said plurality of pressurization steps are sufficient to permit such penetration of said porous load by said vapor that said porous load reaches a general temperature equilibrium with said chamber at about the same time as said chamber reaches said predetermined temperature to avoid superheating said chamber relative to said porous load, each said pressurization step including a pressure rise during which said vapor is injected into said chamber followed by a pressure plateau, greater than the previous pressure plateau, during which said chamber is isolated and said vapor is not injected into said chamber to permit said vapor injected during said pressure rise to penetrate said porous load to displace noncondensable gases and to permit said chamber and said porous load temperature to stabilize; and holding said chamber at said predetermined temperature for a predetermined period of time sufficient to sterilize said porous load. - View Dependent Claims (7, 8, 9, 10, 11, 12)
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Specification