GB110053A - Improvements in and relating to Fluid Meters. - Google Patents

Abstract

110,053. White, A. E., (Cutler-Hammer-Manufacturing Co.). Nov. 29, 1916. Anemometers.-The rate of flow of a fluid is measured by supplying heat to another fluid which is brought into heat-exchanging relation with the fluid of which rate of flow is to be measured and measuring the effect of the heat transfer between the medium and the fluid. This may be effected either by measuring the temperature difference corresponding to a constant heat supply or by maintaining the temperature difference constant and measuring the heat stipply. Figs. 1 and 2 show an apparatus in which the fluid to be measured passes through the conduit 1 where it is acted on bv fluid in the coiled pipe 2 which is heated in the heater 9 by means of a fluid burner, comprising a ring 16 having a number of nozzles 15 projecting into the funnel shaped inlets 14 of the burner 6. The temperature of the heating fluid is determined by the thermometer 21 and the initial temperature of the fluid to be metred by the thermometer 22<1>. The change of temperature in the conduit is measured by the differential thermometer 22 which may be graduated directly to indicate the rate of flow. The rate of supply of fuel to the burner is maintained constant by means of pressure regulators 19, 20 and a restricted orifice 18 or the fuel may be measured by the meter 19" and the heat supply thus determined. In a modification an oil burner is used supplied with oil by means of a tank in which a constant head is maintained by a ball-cock. Fig. 4 shows an apparatus in which the fluid to be measured passes through the tubes 49 in the chamber through which passes the products of combustion and heated air from a burner which may consist of a chamber 43 having nozzles 47 under the burner sleeves 48, air being drawn in through the ports 42. The differential thermometer 22<b> having tubes 23<b>, 24<b> determines the difference of temperature. Fig. 6 shows an apparatus in which the fluid passes through the tube 55 provided with a number of perforated baffles 61 heated by means of the gas burner 64, the products of combustion of which pass around the tube and out of passage 67. The heating and thermometry may both be electrical; in Fig. 10 the fluid is heated by means of a resistance coil i, Fig. 11, in an air current passing through tubes c in the conduit a, the air being circulated by means of a fan i. The thermometer apparatus is similar to the heating apparatus, the temperature being determined by measuring the resistance of the coil. The flow of fluid may be determined either by keeping the power supply to the coil j constant and determining the difference of resistance in the thermometer coils, or by keeping the difference of resistance constant and measuring the power supplied to the heating coil. Fig. 13 shows diagrammatically an apparatus for the latter purpose similar to that described in Specification 10454/12. The thermometer coils are connected in a Wheatstone bridge the galvanometer needle 95 of which is in the mid position when the predetermined difference of temperature is maintained, but when deflected is intermittently clamped between contacts 96, 97 to energize one of the two electromagnets 90 which attracts a continuously oscillating pawl 89 and moves the contact arm of the rheostat 87 controlling the current through the heater, the power of which is measured by the wattmeter W. The current through the pawls passes through contact strips 23 of different lengths, on a rotating drum, the arrangement being such that the pawls are attracted for longer periods for a greater deflection of the needle.