GB890875A - Improvements in or relating to methods of operating a high vacuum pump and a pump therefor - Google Patents

Abstract

890,875. Getter pumps. PFEIFFER G.m.b.H., ARTHUR. March 8, 1960 [May 29, 1959], No. 8193/60. Class 8(1). A getter pump comprises two communicating casings 1, 2, casing 1 being connected with the vessel to be evacuated at 5 and casing 2 being connected to a high vacuum pump at 14, means operable to deliver to casing 1 a liquid metal e.g. gallium or gallium alloy getter and to expose the liquid metal getter to gas contained in the first casing while a vacuum is maintained therein by the pump connected at 14 whereby gas is absorbed by the liquid metal getter, means to deliver gas charged liquid metal getter from casing 1 to casing 2, means co-operating with casing 2 to effect degassing of gas charged liquid metal delivered thereto, and means to return the degassed liquid metal getter to the first easing The gallium or gallium alloy is liquid at somewhat above room temperature, e.g. 30‹C. The liquid metal falls as a drizzle from three circular concentric finely perforated pipes 7 on the sloping floor whence it flows via pipe 21 to heat exchanger 20 where it is heated by 600‹C. and then upwardly by pipe 18 to helical channel 16 where coil 25 heats it a further 70‹C. The liquid at 700‹C. is then taken by pipe 19 through the heat exchanger where it is reduced to 100‹C. and then to 30‹C. in cooler 22 after which it is pumped back to pipes 7 through pipe 24. The gas released during the heating is removed by a high vacuum pump connected at 14 and cooling pipes 26 serve to condense metal vapour. A liquid seal is formed by bell 28 and ring 29, bell 28 being secured to angle lever 30 with armature 31 attracted by magnet 32. The bell 28 can thus be opened to produce a high vacuum in 1, 2.