GB521886A - Apparatus for measuring fluid pressures - Google Patents

Abstract

521,886. Pressure gauges. TCHANG, T. L., and RETEL, J. M. R. Dec. 28, 1938, Nos. 37623 and 37624. Convention dates, Dec. 28, 1937, and Nov. 23, 1938. [Class 106 (ii)] Comprises apparatus in which the pressure to be measured acts upon one face of a sensitive device which is subjected on its other face to an adjustable and known opposing pressure, this apparatus comprising supports with which the sensitive device can make contact at points distributed over its surface after a predetermined deformation. A body 1 similar in shape to a sparking plug is screwed into the head of a cylinder, and contains the diaphragm 2, the edge of which is clamped with an interposed insulating ring 3 between abutment plates 4, 5. The plate 4 seats on the bottom of the body 1 and is provided with a series of concentric ribs 6 between which are holes for the passage of cylinder gases to act on the diaphragm, radial passages 8 being provided. The surface 5 is provided on its lower surface with an analogous arrangement. An annular groove around the plate 5 gives it elasticity which permits compensation for thermic expansion. The plate 5 is secured to a rod 10 concentric with a frusto-conical sleeve 11 fixed in the body 1 by a ring nut 12. An insulating washer 13 is located between sleeve 11 and member 5. On the sleeve 11 is a hollow connection 14 having a tube 15 for feeding the gas at known pressure. The rod 10 projects beyond the sleeve and is fitted with a cap 18 separated from the sleeve by an insulating washer 19. A terminal 20 connects the cap with an electric circuit comprising a battery, the primary of a transformer and the metal work of the framework. The secondary of the transformer is in circuit with a neon lamp. As long as the known regulated pressure is lower than the maximum pressure in the cylinder, the membrane is moved off the plate 4 and breaks the primary circuit causing the neon lamp to light up. As soon as the applied known pressure equals the maximum pressure in the cylinder, the lamp fails to light up. A pressure gauge on the gas supply means indicates this pressure. Instead of a membrane a thin disc or light piston moving between plates 4 and 5 may be used. The parts may be made of non-magnetic metals to avoid steel particles becoming fixed to them and affecting their operation. The gas conduit is partly throttled by a rod 31.