Patent ID: 6396064
Filing Date: 2002-05-28
Classification: F04F,H01J

Abstract:
A device for generating and maintaining a gas pressure difference between two chambers, which comprises:(a) first and second chamber interconnected via an aperture; (b) said aperture being defined by the inside wall of an inner nozzle; (c) third chamber connected via an annular orifice with said first chamber; (d) said annular orifice being defined between the outside wall of said inner nozzle and the inside wall of an outer nozzle which surrounds the inner nozzle; (e) said first chamber being maintained at a given gas pressure; (f) said third chamber being maintained at a substantially higher gas pressure than the pressure of first chamber so that gas flows and forms a supersonic annular gas jet in the direction from third to first chamber; (g) said second chamber being maintained at substantially lower gas pressure by the action of said annular gas jet flow; (h) means for supplying a gas in said third chamber; (i) means for removing gas from said first chamber.