GB371504A - Improvements in or relating to pressure-regulated apparatus, particularly pressure gauges - Google Patents

Abstract

371,504. Electrically-actuated valves. BECQ, A., 80, Rue Monge, Paris. Feb. 6, 1931, No. 3879. Convention date, Feb. 6, 1930. [Class 135.] In controlling fluid pressure, or temperatures, use is made of the variation of the electrical resistance of a dry surface rectifier, particularly a coppercuprous oxide rectifier, due to variation of pressure contact between the surfaces, to translate fluid-pressure variations into electric current variations which are used to effect the control of the pressures or temperatures. As shown, the apparatus comprises a chamber 25 having a diaphragm 22 subjected on one side 24 to fluid pressure while its other side is connected to a rod 21 which passes through a guide 26 and is connected to a plate 3 adapted to bear against a copper-cuprous oxide rectifier 1, 2. The rectifier is carried by a block 27 secured to a plate 28 fixed to but 'insulated from chamber 25, and leads are taken from 28, 25 to a battery or other source 30 and indicating or controlling device 31 which are thus in circuit with the rectifier. The device 31 may be a galvanometer calibrated to read pressures, or it may be an electromagnetic relay operated when the current, and therefore the pressure, reaches a critical value in order to prevent further rise of pressure. The fluid may be a gas subject to temperature it is desired to control, and the electromagnet relay may control supply of current to an electric heater. The rectifier may be spring-mounted on plate 28 so that it yields to excessive pressure or it may be arranged so that increase of fluid pressure decreases the pressure on the rectifier. If the movement of the diaphragm is too great or two small, reducing or amplifying devices such as levers may be used. The arrangement may be such that, normally, the plate 3 does not bear on the rectifier, a non-arcing contact being made when pressure increases. Where the source 30 is D.C. it must be poled so that current flows from oxide to copper, but where A.C. is used this precaution is unnecessary. To provide the necessary surface area or to limit the voltage applied across the rectifier two or more rectifying units may be used in parallel or series as the case may be.