Image Number 6 for United States Patent #6875399.
A sterilization system (14) includes a sensor (10) for detection of a component, such as hydrogen peroxide vapor, in a multi-component vapor, such as a mixture of vapor hydrogen peroxide and water supplied to a chamber (12) of the system. The sensor preferably uses a wavelength range in which hydrogen peroxide strongly absorbs but other components of the vapor, such as water, do not. A suitable wavelength for detection of hydrogen peroxide is from about 7500 to about 8400 nm, since there is little absorption by water in this range. This avoids the need to use complex subtraction procedures normally used to remove the contribution of water from detected absorbance measurements. A control system (16, 30) controls operating conditions of the sterilization system, such as a heater (82), pressure release valves (74), vaporization rate of hydrogen peroxide by a vaporizer (22), and the like to maintain optimum sterilization conditions within the chamber.