GB768003A - Improvements in high vacuum pumps - Google Patents

Abstract

768,003. High vacuum pumps. WIS CONSIN ALUMNI RESEARCH FOUN DATION. Nov. 17, 1954 [Nov. 23, 1953] No. 33276/54. Class, 8(1) [Also in Group XL(a)] In a high vacuum pump comprising a chamber 10 connected to a system to be evacuated and containing a crucible which is intermittently or continuously fed with gettering material 16. e.g. titanium wire, the chamber contains gas ionizing means which comprises a cathode 21 and two spaced concentric anodes 22, 23 electrically connected and of grid like construction. The potentials on the cathode, anodes and chamber walls are arranged to cause electrons to oscillate between the cathode and chamber walls. A continuous or oscillating magnetic field may be used to increase the electron path. Ionized gas is driven into the walls and covered by successive layers of getter material. In a modification the getter material is vaporized by engagement with a post heated by electron bombardment. The getter wire may be heated by periodic intense pulses of electrons. The chamber is first evacuated by a fore pump connected through a valve 15 and subsequently a primer getter charge may be vaporized. The Specification gives details of a wire feeding device enclosed within the chamber and actuated by a rotary shaft on the exterior. Mention is also made of a further feeding device operated by expansion and contraction of a steel strip. The getter wire may be supported on another wire which is bound from one reel on to another. The wire feeding device may be shielded to prevent condensation of the getter thereon and the wire may be heated to straighten it.