Method of sterilization specimen conditioning
Methods and systems for modifying a temperature of a product to be sterilized while the product is in a sterilization chamber. Temperature modification may be achieved through air circulation, through manipulation of a temperature of one or more walls of the sterilization chamber, and/or through manipulation of pressure within the sterilization chamber. Using the capabilities of the sterilization chamber to accelerate product warming may reduce the time required to warm a product to be sterilized from a refrigerated state to a temperature at which sterilization is to be performed. After sterilization, the product may also be cooled in the sterilization chamber.
1 . A method of sterilizing a product comprising:
removing the product from cold storage;
placing the product in a sterilization chamber while the product remains below room temperature;
warming the product in the sterilization chamber by cycling pressure, in a warming cycle, within the sterilization chamber between a first pressure and a second pressure, the second pressure being lower than the first pressure, the cycling pressure including:
reducing pressure over a first period of time from the first pressure to the second pressure;
dwelling at the second pressure for a second period of time;
increasing pressure over a third period of time from the second pressure to the first pressure; and
dwelling at the first pressure for a fourth period of time; and
sterilizing the product in the sterilization chamber,
wherein the first period of time is longer than the third period of time.
2 . The method of claim 1 wherein the sterilization chamber includes an air circulation device, and the step of warming the product comprises activating the air circulation device.
3 . The method of claim 2 , further comprising warming air passing through the air circulation device.
4 . The method of claim 1 , wherein the step of warming the product comprises warming the sterilization chamber wall.
5 . The method of claim 1 further comprising, after sterilizing the product, cooling the product in the sterilization chamber.
6 . The method of claim 5 , wherein the step of cooling the product comprises cooling the sterilization chamber wall.
7 . The method of claim 5 , wherein the step of cooling the product in the sterilization chamber comprises cycling pressure for cooling in the sterilization chamber between a third pressure and a fourth pressure, the fourth pressure being less than the third pressure.
8 . The method of claim 7 wherein cycling pressure for cooling comprises:
reducing pressure over a fifth period of time from the third pressure to the fourth pressure;
dwelling at the fourth pressure for a sixth period of time;
increasing pressure over a seventh period of time from the fourth pressure to the third pressure; and
dwelling at the third pressure for an eighth period of time.
9 . The method of claim 8 wherein the fifth period of time is shorter than the seventh period of time.
10 . The method of claim 5 , wherein the sterilization chamber includes an air circulation device, and the step of cooling the product comprises activating the air circulation device and cooling air passing through the air circulation device.
11 . The method of claim 1 , wherein the second pressure is an ambient pressure, and the first pressure is higher than ambient pressure.
12 . The method of claim 1 , wherein the first pressure is about 100 kPa, and the second pressure is about 75 kPa.
13 . The method of claim 1 , wherein the first pressure is about 100 kPa, and the second pressure is about 50 kPa.
14 . A sterilization system comprising:
a sterilization chamber configured to contain a product, the sterilization chamber including:
a sterilant source configured to communicate a sterilant into the sterilization chamber, the sterilant configured to sterilize the product;
a vacuum source configured to adjust pressure in the sterilization chamber; and
a blower configured to circulate air in the sterilization chamber; and
a control and monitoring system for controlling conditions in the sterilization chamber, the control and monitoring system configured to perform a method comprising:
warming the product in the sterilization chamber by cycling pressure within the sterilization chamber between a first pressure and a second pressure via the vacuum source, the second pressure being lower than the first pressure, the cycling pressure including:
reducing pressure over a first period of time from the first pressure to the second pressure via the vacuum source;
dwelling the sterilization chamber at the second pressure for a second period of time;
allowing gas to enter sterilization chamber to increase pressure over a third period of time from the second pressure to the first pressure, the first period of time longer than the third period of time; and
dwelling at the first pressure for a fourth period of time; and
sterilizing the product in the sterilization chamber using the sterilant source.
15 . The system of claim 14 , wherein the control and monitoring system is configured to perform the step of warming the product by warming the sterilization chamber wall while the pressure is cycled between the first pressure and the second pressure.