GB810092A - Improvements in or relating to gas meters of the dry type - Google Patents

Abstract

810,092. Gas meters. PARKINSON COWAN Ltd. [formerly PARKINSON & COWAN Ltd], Oct. 11, 1955 [Oct. 11, 1954; Feb. 28, 1955; April 25, 1955], Nos. 29284/54, 5930/55 and 11937/55. Class 54. A gas meter has a double - acting piston 20, Fig. 6, mounted between two measuring chambers 27, 28, the piston being provided with two diaphragms 25, 26 forming a space 29 which is maintained at a pressure higher than or equal to the inlet pressure or lower than or equal to the outlet pressure, but not between the inlet and outlet pressures. The space is preferably maintained at inlet or outlet pressure and receives a pivoted yoke 32 to connect the piston 20 to the valve mechanism and meter index. Fig. 8 shows a construction in which two cylindrical diaphragms 35, 36 are used. The piston may have a narrower cylindrical portion 20b than that shown and be connected to the meter mechanism by a piston-rod passing through a stuffing-box in one of the pans 21. A double diaphragm, such as that shown at 39 in Fig. 11, may be used, two wires 40 serving to secure the diaphragm to the piston 20. A series of apertures 30a connects the space 29 to that surrounding the pans 21. Fig. 13 shows a double diaphragm member moulded from rubber, synthetic rubber or synthetic plastic-covered fabric. The web 42 to which discs are clamped on either side may be apertured or omitted. In Fig. 16, the web 46 acts as a piston and has attachment points 47 for the meter mechanism. A space 48 may be inflated to a pressure above the inlet pressure with inert gas before the diaphragm is mounted or a tube for communicating pressure to the space 48 may be provided. Specifications 504,424 and 810,021 are referred to.