GB652880A - Improvements in or relating to differential pressure measuring devices - Google Patents

Abstract

652,880. Pressure gauges. JONES, B. Jan. 2, 1948, Nos. 159 and 160. Convention dates, June 11, 1943, and March 28, 1944. [Class 106 (ii)] Pressure responsive means such as bellows 116, 117, on opposite sides of a support 113 and rigidly connected so as to move as a unit, are normally in communication with one another and are filled with an incompressible liquid. The differential between pressures conducted to the interior of housing 110 and acting on the exteriors of the bellows causes the unit to act, e.g. on a lever 124, and communication between the bellows is closed off if this differential pressure becomes excessive. As shown, the bellows are connected by a rod 120 passing through a hole in the support 113 and the closing-off means comprise valves 122, 123 on the rod. The support 113 divides the housing into two chambers 114, 115 which receive liquid or gas from different pressure sources, e.g. opposite sides of a venturi tube. The bellows are acted on by springs 118, 119 and filled with liquid such as kerosene or glycerine through a small bore 129. An auxiliary bellows 126 allows for expansion and contraction of this liquid due to temperature changes. The lever 124 is connected to a rock-shaft 125 mounted in special bearings and connected to indicating mechanism (not shown). This lever and associated mechanism may be replaced by a hydraulic or electrical indicating device. A slightly modified pressure gauge without the auxiliary bellows 126 is also described.