GB1094885A - Meter for measuring unsteady fluid flow - Google Patents

Abstract

1,094,885. Measuring fluid-flow electrically. MARTIN MARIETTA CORPORATION. Sept. 21, 1966, No.42167/66. Headings G1N and G1R. The rate of flow of a fluid through a conduit is determined by dividing the conduit into two passageways of varying cross-section, thereby creating a pressure difference along the passageways which is indicative of the rate of flow, and is measured electrically. As shown (Fig. 1), a frustro conical member 25 is located axially in a conduit C, supported centrally by vanes 30, having a bellmouth entry 28 leading to a constant diameter bore 26. Attached to the base 29 of the cone by a neck 34 (Fig. 2) is a thin ferromagnetic ring 31 with a longitudinal slot 32. The changes in cross-sectional area between the inner and outer passageways produce a pressure difference which causes the ring 31 to expand, thereby altering the width of the slot 32 in accordance with the overall rate of fluid-flow. Mounted over the slot 32 is a U-shaped core assembly 35 with the two legs 36 in the slot 32 so that the magnetic circuit is completed through the ring 31. Two coils 42, 43 are wound on the core 35, and their inductances, as measured in a bridge circuit, are indicative of the width of the slot 32. The construction of the insert in the conduit C may be modified by (a) providing more than one change in flow crosssectional area Fig. 7 (not shown), (b) combining the conical member 25 and the split ring 31 Fig. 8 (not shown), (c) adding a further conical member on the other side of the split-ring to measure flow in either direction Fig. 10 (not shown). In a further embodiment (Fig. 11), the inner passageway comprises a tube 65 tapered from the middle outwards. The pressure at th throat 67 is fed by taps 68 to a manifold ring 69, nd the corresponding pressure in the outer passageway is fed by taps 68a to a manifold ring 7. The pressure difference is indicative of the rate of flow in either direction.