GB883189A - Electrical vacuum pump and vacuum gauge apparatus - Google Patents

Abstract

883,189. Discharge apparatus. VARIAN ASSOCIATES. July 2, 1958 [July 24, 1957], No. 21237/58. Class 39(1). A getter pump or vacuum gauge comprises a closed envelope connected to a structure to be evacuated and having within it a cathode structure and an anode structure with a glow discharge between them and a magnetic field, the anode structure having a plurality of spaced openings distributed transversely to the magnetic field and each defining a separate path for the glow discharge, these paths being parallel to the direction of the magnetic field. In one embodiment a cylindrical cellular anode 18 Fig. 2 of molybdenum is carried by conducting rod 19 insulated from copper envelope 20 and provided with a shield 26 to prevent deposition of cathode material on insulator 23, and cooling fins on a block 24. Cathode plates 25 are mechanically secured together forming a lining to envelope 20. Conduit 2 is connected to the system to be evaporated and magnetic pole pieces 27 are provided to increase the electron path. The cathode is of Mo, Cr, W, Ta, Ni, Fe, Ti, Zr, Ni, Ba, Al, Th, Mg, Ca, Sr or other transition elements of the 4th, 5th and 6th Group of the Periodic Table including the rare earths, which when atomised condenses particularly on the anode surfaces, to entrap gas molecules. One of the cathode plates 25 may be provided with pins projecting into the anode cells, Fig. 15 (not shown) or two opposite plates may be replaced by a number of louvres, Fig. 6 (not shown). The anode walls may be apertured to aid diffusion. In further embodiments the anode and cathode may comprise interleaved plates 75, 76 and 78 respectively, which may have apertures 81, Fig. 16, or the anode and cathode may be concentric cylinders 66, 64 Fig. 12 and 67, 71 carried by plates. A plurality of parallel anode plates may co-operate with a rectangular box cathode, Figs. 18-19 (not shown). The device operates on D.C., A.C. or pulsating D.C.