GB691537A - Improvements in or relating to connections for pressure gauges - Google Patents

Abstract

691,537. Pressure gauges. GRANT, C. R. A., and PRESSURE GAUGES, Ltd. July 18, 1951 [July 21, 1950], No. 18297/50. Class 106 (ii). [Also in Group XXIX] In a gauge connection for connecting a pressure gauge to a gas pressure system, the gas pressure is transmitted to the gauge through a column of liquid in which there is interposed an obturating member, the obturating member being carried, in the event of failure of the gauge, to a position in which it closes, or substantially closes, the said connection. In Fig. 1 the obturating member is a piston 27 in a cylinder 11, the gas pressure acting through a port 23 on the liquid in a chamber 25, the liquid extending up the cylinder 11, coaxial with the chamber 25, to a pressure gauge mounted on a stem 10. The piston 27 is so dimensioned in relation to the cylinder 11 that it provides a restricted leakage path between the cylinder and the gauge, the spacing between the surfaces providing this restricted leakage path being not more than fifteen ten thousandths of an inch. Should the gauge fail, the piston 27 is carried upwards by the liquid until it engages a shoulder 13 to substantially close the connection. A valve controlled supply fitting 19 between the cylinder 11 and the pressure gauge enables liquid to be introduced to the connection. In a modification the liquid chamber 25 and the cylinder 11 are arranged side-by-side and are connected together at their lower ends. According to a further modification, Fig. 3, pipes 53 and 50 connected respectively to the gas pressure system and the cylinder 11 extend into a closed chamber 51 and communicate with said chamber through orifices 52, 54 in the tubes 50,.53 submerged in liquid in the chamber 51. Specification 670,344 is referred to.