GB832341A - Improvements in or relating to valve means in pressure fluid systems - Google Patents

Abstract

832,341. Pressure gauges. FENN, A. G., and HUNT, R. J. April 27, 1956 [April 28, 1955], No. 12225/55. Class 106 (2). [Also in Group XXIX] Fluid from a system 8, Fig. 1, enters a chamber 14 from which it flows to a gauge 9, via a cut-off lift valve 11 normally opened by an adjustable spring 16, and a chamber 20; fluid from the latter also enters another chamber 23 through a duct 22 to act downwardly on a diaphragm 25, the underside of which is subjected to inlet pressure by way of a duct 26. As the pressure in the system 8 rises a diaphragm 15, connected to the valve 11 and forming the lower wall of the chamber 14, is deflected against the spring 16 to close the valve 11; a further pressure rise so increases the upward force on diaphragm 25 that it is lifted to open a release lift-valve 12 normally closed by an adjustable spring 33 so that fluid trapped in the gauge 9 and chamber 23 escapes to a reservoir via valve 12, a chamber 30 and a conduit 32. The upper wall of the chamber 30 is formed by another diaphragm 31. The springs are adjusted to ensure that valve 11 opens at a lower pressure than valve 12. The valves automatically return to their normal positions on a diminution of the supply pressure. In a modification, fluid enters interconnected chambers 37, 38, Fig. 2, and since parallel levers 63, 66 are loaded upwardly by a spring 71, the cut-off valve 11 is unseated by the fluid, with upward deflection of a diaphragm 57, which then passes into chambers 51, 50, joined by a conduit 52, and the gauge 9 by duct 22. As pressure builds up in the chamber 38 a diaphragm 41, forming the bottom wall thereof, is moved downwardly since the unsupported area of this diaphragm is greater than that of diaphragm 57; the spring 71 is thereby overcome and the levers 63, 66 pivot downwardly and the valve 11 is closed. Continued pressure increase in chamber 37 causes downward deflection of a diaphragm 40, contiguous with diaphragm 41, resulting in a similar movement of a further pair of levers 64, 65 against a spring 77 and another diaphragm 58, contiguous with diaphragm 57, thus opening the release valve 12 against its spring 55 so that fluid trapped in chambers 51, 50 and the gauge 9 escapes into a chamber 56 connected to a reservoir by a duct 32. Diminishing pressure in the system enables the valve 12 to close and valve 11 to open. The valves may be arranged as separate units; where several gauges are used the pairs of valves associated with each gauge enable the fluid to be independently released from the gauges at the different pressures. Fluid is gradually applied to each gauge through a throttled opening, formed by the inlet 13 for example. According to the Provisional Specification the loading spring of the release valve may be dispensed with and the valve suitably weighted to provide the required loading.