Patent GB-380089-A (GB)
Title: Improvements in or relating to rotary fluid flow meters
IPC: G01F1/12
Filed: 1931-06-09
Abstract: 380,089. Recording apparatus. KENT, Ltd., G., 199, High Holborn, London, and HODGSON, J, L., Eggington House, near Leighton Buzzard, Bedfordshire. June 9, 1931, No. 16747. [Class 106 (iv).] A gas flow meter comprising a vane wheel actuated by the gas flow, and a damping device for the vane wheel, is provided with means controlled by the pressure of the gas which co-operate with the amount of gas registered by the vane wheel mechanism to enable the true flow of gas to be registered despite change in density of the gas. A vane wheel 1, mounted on a spindle 5, is rotated by gas passing through a passage 2, the main gas flow passing through an orifice 3. A paddle wheel 6, on the same spindle, moves in a liquid of constant density to damp the speed of the wheel 1. The surface of the liquid is subjected to the gas pressure, and the fluctuations in the latter cause responsive movements in a Bourdon gauge tube B which is connected to a pipe 32. The free end of the tube B is pivoted to an adjustable link 34 which through a plate 35 secured to a spindle 36, turns the spindle and a finger 37 upon which is mounted a pen 38 which presses against a chart 26. To alter the scale of the pen finger movements the plate 35 is split and the two portions may be forced apart by a wedge actuated by an adjusting screw 40. A plate 27, which supports the chart 26, is cut away at 41 to permit this adjustment. A hole 43 permits access to the pivoting screw 44 on the link 34. A toothed wheel 9 on the spindle 5 drives a train of gears 11 and a toothed wheel 12 on a second spindle 13 to which is clamped a magnet 14. A second magnet 15 moves in sympathy and turns a third spindle 16 and through bevel gears 18, 19, operates a gear train 21 which drives the counting mechanism 45. The latter is calibrated in thousands of pounds and is visible through a glass panel 46. If steam is being metered the damping liquid may be water, make-up water being provided by condensed steam. The chart operating mechanism is mounted in a casing 48 secured to tne counter casing 17 by screws 49, accessible through apertures 50. For alignment purposes a flange 52 is provided. A thrust race 29 takes end pressure due to screwing up the nut 25 which secures the chart 26. A glazed door 42 is provided. The periphery of the chart may be marked at regular intervals by a clock. The pen 38 is displaced from its zero position through a distance proportional to the corrective factor which is given by the formula Q ##<W>/W1 dN where #<W>/W1 is the corrective factor, W1 being a particular density of the gas, W a variable density, Q the true flow in weight units, N the registration of the counter geared to the vane wheel 1. The charts are also provided with pressure lines. In a modification the drive between the vane wheel and the counter is arranged to be interrupted to an extent dependent on the pressure of the gas, the arrangement comprising a transmitting gear wheel, which is moved into and out of mesh with a gear driven by the vane wheel, driving the counter mechanism, a cam device for effecting this movement being controlled by the Bourdon tube.