GB555626A - Improvements in pressure gauges - Google Patents

Abstract

555,626. Pressure gauges. FAWCETT, PRESTON & CO., Ltd., and RHODES, A. May 29, 1942, No. 7277. [Class 106 (ii)] Comprises three coaxial and mutually displaceable elements which form a fluid chamber, one element being displaceable in accordance with the pressure in a fluid line, and a second element, having a smaller effective pressure area in the chamber than the first, to give increased movement being connected to an indicator while the third element carries a scale. A cylindrical casing 1 open to the atmosphere at 2 encloses a cylinder 3 having radial perforations 4, the cylinder 3 being open at one end to receive a double piston or ram consisting of outer and inner tubes 5, 6, the tube 5 having a liner 7. A spring 8 is disposed between a collar 9 fixed to the tube 5 and the top end of the cylinder 3, the collar being extended radially to carry an indicating finger 10 sliding through a slot 11 in an outer casing 12 which is adjustably connected by screw and nut means 13 to the inner piston 6. A plug 18 closes the lower end of the cylinder 3 which can be displaced against the influence of the spring 8 by a plunger 14 displaced in a nipple 15. The casing 1 is filled with oil or the same type of fluid as that in the pipe line connected to the nipple 15. In use, pressure from the pipe line acts on the plunger 14 which moves the cylinder 3 against its spring 8 until the perforations 4 are masked by the tube 5 which the rising pressure in the cylinder 3 will be communicated to the hollow piston element 13 driving it upwards in the tube 5 and displacing the sleeve 12 which has a scale which can be read against the index 10.