Apparatus and method for detecting moisture in a vacuum chamber

A method of operating a sterilization system having a vacuum chamber for sterilizing instruments, comprising:

• (a) initiating a timer in a digital computer;
• (b) withdrawing a first volume of air from the chamber;
• (c) repeatedly determining pressure within the chamber while withdrawing the first volume of air from the chamber;
• (d) calculating, with the digital computer, a first second-derivative value of pressure with respect to time;
• (e) calculating, with the digital computer, a second second-derivative value of pressure with respect to time, the second second-derivative value corresponding to a time subsequent to the time corresponding to the first second-derivative value;
• (f) determining, with the digital computer, that the second second-derivative value is greater than the first second-derivative value;
• and
• (g) automatically introducing a second volume of air into the chamber.

A method of operating a sterilization system having vacuum chamber for sterilizing instruments, comprising:

• (a) initiating a timer in a digital computer;
• (b) withdrawing a first volume of air from the chamber;
• (c) repeatedly determining pressure within the chamber while withdrawing the first volume of air from the chamber;
• (d) calculating, with the digital computer, a first second-derivative value of pressure with respect to time;
• (e) calculating, with the digital computer, a second second-derivative value of pressure with respect to time, the second second-derivative value corresponding to a time subsequent to the time corresponding to the first second-derivative value;
• (f) determining, with the digital computer, that the second second-derivative value is greater than the first second-derivative value;
• and
• (g) automatically introducing energy into the chamber.

A method of operating a sterilization system having vacuum chamber for sterilizing instruments, comprising:

• (a) initiating a timer in a digital computer;
• (b) withdrawing a first volume of air from the chamber;
• (c) repeatedly determining pressure within the chamber while withdrawing the first volume of air from the chamber;
• (d) calculating, with the digital computer, a first second-derivative value of pressure with respect to time;
• (e) calculating, with the digital computer, a second second-derivative value of pressure with respect to time, the second second-derivative value corresponding to a time subsequent to the time corresponding to the first second-derivative value;
• (f) determining, with the digital computer, that the second second-derivative value is less than the first second-derivative value;
• and
• (g) automatically introducing a sterilant gas into the chamber.

A method of operating a sterilization system having a vacuum chamber for sterilizing instruments, comprising:

• (a) initiating a timer in a digital computer;
• (b) withdrawing a first volume of air from the chamber;
• (c) repeatedly determining pressure within the chamber while withdrawing the first volume of air from the chamber;
• (d) calculating, with the digital computer, second-derivative values of pressure with respect to time;
• (e) calculating, with the digital computer, a summation of positive differences between consecutive second derivative values;
• (f) comparing the summation to a threshold value;
• (g) opening a valve;
• and
• (h) opening the chamber.