GB219731A - Improvements relating to electric vacuum tube devices and the like - Google Patents

Abstract

219,731. Robinson, E. Y. April 27, 1923. Aspirating-apparatus, ejector.-A water-cooled exhaust pump of the Langmuir type for use with thermionic valves is provided with a protective device operated on partial or complete failure or other undesirable condition of the supply of cooling water so as to open the circuit supplying energy to the valves or connect an auxiliary supply of water. Fig. 1 shows an arrangement in which the operation of such. a protective device depends on the supply of cooling water to thermionic valves. A pressure relay is connected with the outlet pipe 5 of the cooling system and consists of a U-tube 17 containing mercury and provided with two contacts, which, when bridged by the mercury, close the circuit of a winding of a relay 23 so as to energize a winding 25 operating a switch 26, which controls the supply of energy to the valves. When the supply of water fails or is reduced the relay 23, and, consequently, the switches 26, 28 are opened, so that the supply of energy to the valve is interrupted. Alternatively, the tube 17 may connect an auxiliary of water. The tube has two bulbs as shown so as to prevent disturbance of the mercury due to fluctuations in the water supply. In the arrangement shown in Fig. 6 the anodes 2 are insulated from earth by using long glass or indiarubber pipes 91, 92, for the supply of water. If the water supply fails or falls below a predetermined minimum the relay closes the lower contacts to ring a bell 105, close the valve 95, and open the valve 103 so as to bring the auxiliary water supply 104 into operaiion. A pressure head may be provided by means of constrictions 108. The contacts of a pressurerelay for a pump are connected in series with the contacts of the pressure-relay 96. The U-tube may be of metal forming one contact, the other consisting of an adjustable insulated rod dipping into mercury. In another construction a piston operated by pressure of water normally closes the relay contacts but opens them when the pressure falls. In a modified arrangement a thermal relay is used consisting of a thermometer mounted in the cooling jacket in contact with the anode, the contacts being arranged to operate a relay of the type shown in Fig. 1, when the temperature rises due to failure of the water supply; or a pressure or ionization gauge connected with the interior of the valve may operate the relay when the temperature inside the valve rises.