Abstract: Method and apparatus for providing a low temperature environment at a substantially constant and uniform temperature. A closed chamber is provided with an inlet and outlet. The chamber is operated at subatmospheric pressure. Steam is introduced into the chamber for providing the heating environment at a preselected temperature. A vacuum is applied to the chamber to regulate the steam about its saturation point for a preselected temperature.

Abstract: A seal for a pressure chamber is provided. The seal is formed by welding a loop of rigid tubular material to the perimeter of the entry of a pressure chamber, conforming to the shape of the parameter. A side wall of this tubing is machined off to produce a continuous slot and a "C"-shaped channel running along the perimeter of the entry. Tubular gasket material is positioned in this "C"-shaped channel to extend partially out of the slot to seal against the door of the pressure chamber. A large diameter gasket may be used, and the interior of the gasket may be pressurized by a vent channel connected with the interior of the pressure chamber.

Abstract: An apparatus for exposing objects to saturated steam at subatmospheric pressure is computer controlled during a conditioning phase prior to the commencement of an exposure phase to apply vacuum to a sealed chamber while steam is simultaneously being injected to that chamber. The fluid stream flowing through the chamber sweeps air and condensate from the chamber and creates a partial vacuum within the chamber. The steam flow rate is controlled to establish the desired exposure temperature within the chamber. Vacuum is controlled to establish an exposure pressure at which steam is saturated at the exposure temperature. The exposure phase commences after the exposure temperature and pressure are established within the chamber.