Improvements in or relating to fluid flow meters

Abstract

Abstract 286,469. Sandison, A. G. S., and Electrofio Meters Co., Ltd. March 17, 1927. Liquid-level pressure gauges.-In a fluid flow meter the measuring circuit is controlled by the differential pressure across an orifice 2 and automatic means is provided, controlled by, and to correct for pressure, temperature, or density variations by adjusting the voltage tapping on a transformer in the measuring circuit. Fig. 3 shows a differential manometer 5 varying a resistance 1 in circuit with indicating, recording or indicating instruments having a current winding 7. Correction is applied by movement of one or more contact brushes 15 over tappings 12 on the transformer 10 to vary the voltage applied to either the control winding 8 or to the circuit including the resistance 1 and the current winding 7. The contacts and brushes are preferably so arranged that no brush 15 touches two contacts 12 at once and the resistance 16 between a pair of brushes is sufficient to limit the current when two contacts are engaged. In a modification one set of brushes and contacts is arranged in the primary and another set in the secondary of an auto-transformer in the circuit including resistance 1 and the current winding 7. Fig. 5 shows a construction in which correction is made for one variable by means of a Bourdon tube 43 arranged to rotate an arm 38 carrying brushes 15 attached to flexible strips 35 moving over the tapping contacts 12 of the transformer 10. A pointer 48 is carried by the arm 38 to indicate temperature or pressure, in the former case the inlet 47 is connected to a bulb containing an expansible medium subjected to the temperature to be corrected for.

Inventors

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