GB645490A - Meter for liquids flowing in pipes - Google Patents

Abstract

645,490. Niscosimeters. DYMOTT, E. R. Sept. 2, 1948, No. 24332/47. [Class 106 (ii)] [Also in Group XXIX] In a meter for use with flowing liquids, of the type in which a member is arranged to move within a pipe section against a resisting force, the member by itself, or in conjunction with the pipe, reducing the cross-section available for flow to a value which remains constant at all positions of the member, means being provided for measuring the force exerted on the member caused by flow, the number, length and crosssection of the passages constituting the reduced flow cross-section are made such that in the case of constant viscosity and varying rate of flow, the force on the member is substantially linearly proportional to the rate of flow. If the rate of flow of different liquids remains constant, the meter can be calibrated to measure viscosity. In the form shown in Fig. 1, a piston 6 slides easily in a meter tube 3, of glass or other transparent material, has a number of relatively small bores 7, and is controlled by a tensionspring anchored to the piston by a split pin 8 and to a stirrup 9 carried by a ring 10. The tube 3 is coupled by flexible sleeves 4, 5, e.g. of rubber, between metal tubes 1 and 2, of slightly greater bore, representing a liquid line. The liquid flow is upward and to prevent damage to the spring when the flow-rate is zero, a metal sleeve 11 is provided where shown. To prevent damage to the piston and spring at excessive flow rates, a washer 12 may be placed where shown. The position of the piston on a scale 13 gives the rate of flow. The above form can be used inverted for downward flow, horizontally or inclined when a piston of suitably chosen materials, or a hollow piston, is employed. The passages may be flutes, grooves or channels in the periphery parallel with the axis. The piston may slide on a fixed rod, to provide a shallow peripheral passage. Two or more opposing springs may be used and they may be arranged to balance the weight of the piston. Instead of a spring the piston may be made to raise a chain from a support. The position of the piston in an opaque tube could be communicated by magnetic, electrical or other methods. A remote indication can be given, for example, by having a piston carrying an electrode, which co-operates with another electrode to form a condenser, the whole being enclosed within an earthed electrostatic shield, readings of capacity indicating the rate of flow. Alternatively, the piston could carry a soft iron skirt co-operating with a winding on the outside of the meter tube, inductance readings indicating the rates of flow. In the form shown in Fig. 2, the piston 6 has inclined grooves 14 in its periphery. Due to their inclination the flow tends to rotate the piston and this is resisted by a torsion strip 15 anchored to the ring 10. The strip 15 carries a mirror 16 whereby a beam of light co-operates with a scale, the tube 11 being cut away at 17 for this purpose.