Method for steam sterilization of articles

A process for the steam sterilization of articles by controlled delivery of steam from an electrically heated boiler in free communication with a pressure chamber through a delivery conduit, said boiler having means for detecting dryness of said boiler and said pressure chamber having a venting conduit and a valve for opening or closing said venting conduit comprising:

• (a) generating a flow of saturated steam through said steam delivery conduit by the pulsed injection of a controlled quantity of water into said heated boiler only when dryness of the boiler is detected, said boiler and said pressure chamber being in free communication with each other always and jointly sealed from the atmosphere when said valve is in the closed position such that the pressure in the chamber becomes substantially the same as the pressure in the boiler;
• (b) permitting steam from the boiler to pass into the chamber at substantially atmospheric pressure with said valve open to expel the air initially in said chamber through said venting conduit and determining when substantially all air in the chamber has been expelled by measuring only the temperature of an effluent stream vented from the chamber;
• then
• (c) closing the valve after expulsion of the air so that steam generated in the boiler raises the temperature and the pressure in the chamber and monitoring the temperature in the chamber until a desired sterilization temperature is attained;
• then
• (d) controlling the temperature in the chamber to remain substantially constant at said sterilization temperature for a desired sterilization period by modulating the electric power supply to the boiler;
• and
• (e) at predetermined intervals during pressurization of the chamber in step (c) and during maintenance of the sterilization temperature within the chamber in step (d), opening said valve to cause condensed liquid water from the chamber to be purged therethrough, then closing said valve;
• and
• (f) upon completion of sterilization exposure of the articles in the chamber, turning off the boiler and opening said valve to exhaust the chamber and return it to atmospheric pressure.