GB814289A - Improvements in or relating to low pressure thyratrons - Google Patents

Abstract

814,289. Thermionic valves. M-O VALVE CO. Ltd., COOK, K. G., and ISAACS, G. G. July 27, 1956 [Aug. 11, 1955], No. 23237/55. Class 39(1). The anode of a thyratron is surrounded by the control electrode, and between them is interposed another electrode which also surrounds the anode, the arrangement being such that no lines of force exist between any adjacent pair of these electrodes which are more than twice as long as the minimum spacing between them. In the Fig., the control electrode 4 is shown as a cylindrical box 20 with plane ends 21, 22 parallel to the anode 6. The end 22 is perforated, and screened by a baffle 23. Concentrically within this electrode is a similar box-like electrode 5, acting as an auxiliary anode. This also has plane ends 16, 17 parallel to the anode, and a baffle 18 screening a perforated part. Suitable spacings are given for all these electrode parts. In operation, when 50 kV are applied to the main anode, the auxiliary anode is tapped off at 25 kV. The control electrode is at cathode potential, so that a p.d. of only 25 kV exists between control electrode/auxiliary anode, and auxiliary anode/main anode, which is not sufficient to cause breakdown with the specified electrode spacing and gas filling, which is hydrogen at ¢ mm. The anode 6, auxiliary anode 5, and control electrode 4 are supported by a series of coaxial glass sleeves 14, 30, 34, 37, united with the glass envelope at their upper ends. Between and adjacent these are disposed nickel sleeves 31, 39, and nickel gauze sleeves 35, 38. Sleeves 31 and 35 are attached to the auxiliary anode, enclosing between them the lead 9, and sleeves 38 and 39 are attached to the control electrode. By thus reducing the lengths of the lines of force between neighbouring electrodes, the possibility of breakdown is reduced, giving a higher holdoff voltage for the particular conditions obtaining.