GB981171A - Improvements in or relating to rotary fluid flow meters - Google Patents

Abstract

981,171. Rotary liquid-flow meters. Soc. Anon. POUR TOUS APPAREILLAGES MECANIQUES. Nov. 22,1963 [Nov. 23, 1962], No. 46235/63. Heading F1F. . A rotary liquid-flow meter of the turbine type comprises a rotor having a shaft 3 (Fig. 2) mounted on stationary journals and carrying two sets of helical turbine blades 2 of identical form but opposite direction of twist and a liquid-deflecting disc 4 at its centre. Liquid entering a stationary casing 1 through a conduit 6 divides and passes through perforated baffle plates 7, 8, flow-straightening vanes 9, annular nozzles 11 and passages 10 before flowing between the blades 2. The spent liquid is deflected outwardly by the disc 4 into a passage 12 leading to a discharge conduit 13, the action of the liquid on the disc 4 serving to centre the shaft 3 and prevent end thrust on the journals, thereby minimising frictional resistance. A proportion of the liquid entering the meters through a conduit 15 (Fig. I) passes through a pair of pipes 17 containing regulating valves 18, the remainder passing into conduit 6 through a pressure-reducing non-return valve 16. The liquid passing through pipes 17 enters passages 10 through annular grooves 19, radial passages 20 in plates 8, annular grooves 26 and passages 27 arranged tangentially to passages 10, whereby the flow of liquid in passages 10 is rendered both tangential and axial to minimise errors at low flow rates. The pressure of the liquid in passages 27 is greater than that of the fluid leaving nozzles 11 owing to the loss of pressure at valve 16 and in the nozzles. In an alternative embodiment (Fig. 4) most of the liquid entering the meter passes through a pressure-reducing non-return valve 24 whilst the remainder passes through pipes 21 and fluid bearings for the shaft 3 before entering the nozzles 11; this embodiment is otherwise similar to that shown in Figs. 1, 2. Valve 24 may replace valve 16 in the first embodiment, and in both embodiments the rotor may be coupled to volume indicating or recording mechanism (not shown).