GB857663A - Improvements in or relating to dry gas meters - Google Patents

Abstract

857,663. Gas meters. CONTINENTAL SPRAGUE METER ITALIANA S.p.A. Jan. 23, 1957, No. 2368/57. Class 54. A dry gas meter has a pair of diaphragms 11, 12 which drive a single shaft 20 and divide the meter into three measuring chambers 7, 8, 9, and a valve comprising an apertured disc 30 moved in a circular path over a grid 24 places each of the measuring chambers in succession in communication alternately with a gas supply chamber 59 and a gas outlet chamber 29. The diaphragms are linked by rods 14, 17 to the shaft 20, the rod 14 being connected to a slide 18a adjustable in an arm 18 by a screw 71 and the rod 17 being connected to a pin 74 which depends from a crank 19 secured to the shaft by a screw 70 and forms a pivot for the arm 18. A crank 30a on the shaft 20 has a pin 54 fitting in a bearing 13 in a lid 56 over the disc 30 and a stud 31 on the lid is connected to a crank 32 for driving an index 35 through a gear-box 35a. The disc 30, which is preferably made of glass, slides in a circular path over three lateral apertures 25, 26, 27 and central aperture 28 in the grid. An elastic membrane 38 acted on by an adjustable spring 42 is linked to a valve in the supply union and is lifted by excess pressure in the supply chamber 59 so that the valve restricts the flow of gas to the chamber. In Fig. 6, the lateral aperture 27 is exposed beyond the periphery of the disc to supply chamber 59 so that gas flows to the central measuring chamber 7 through a passage 53, while the lateral aperture 25 is exposed by the disc aperture 58 so that gas from the chamber 9 flows through a passage 51 to the discharge chamber 29 by reason of the outward movement of the diaphragm 12. As the disc travels counter-clockwise, the aperture 27 is masked and then exposed to the aperture 58 so that the central chamber can discharge as the aperture 25 is masked to terminate flow from the chamber 9 and the aperture 26 is opened to fill the chamber 8 through a passage 52 and moves the diaphragm 11 inwardly. Subsequently chamber 9 again starts to fill and both diaphragms move inwardly until the central chamber 7 is fully discharged and then the central chamber starts to fill again and causes discharge from the chamber 8. During the travel of the disc two of the lateral apertures may be exposed simultaneously by the periphery or by the central disc aperture 58 but at no time are any two lateral apertures exposed to the supply chamber at the same time as one of the two apertures is exposed to the central disc aperture so that unmetered flow is not possible.