Vacuum chamber with a supersonic flow aerodynamic window

Apparatus for creating and maintaining a vacuum in a primary chamber which has an opening to the atmosphere or other region of higher gas pressure, by formation of an aerodynamic window before said opening, said apparatus comprising:

• wall means defining said primary chamber, said primary chamber adapted to be coupled to a source of vacuum pressure, and having a wall thereof provided with an orifice which communicates with the atmosphere or said region of higher gas pressure;
• ejector means connectable to a source of superheated steam for ejecting superheated steam into said primary chamber in the direction toward said orifice;
• mixing chamber means for mixing superheated steam with gas from the atmosphere, said mixing chamber means being coupled in fluid communication with said orifice, and having an aperture communicating with the atmosphere or said region of higher gas pressure;
• nozzle means for injecting superheated steam into said mixing chamber means, said nozzle means being connectable to a source of superheated steam;
• cooling means mounted to the inside of said primary chamber for effecting the condensation of superheated steam introduced into said primary chamber from said ejector means and said mixing means, said condensation thereby enhancing the vacuum condition of said primary chamber;
• and
• drain means connectable to said primary chamber for removing the condensate from said primary chamber without disturbing the vacuum condition of said primary chamber,
• whereby superheated steam is introduceable into the primary chamber from said ejector means to collide with the mixture of atmospheric gas and superheated steam injected into the primary chamber from said mixing chamber means to form an aerodynamic window in front of said primary chamber orifice which restricts the flow of gas into said primary chamber from the atmosphere or other region of higher gas pressure.