GB800072A - Improvements in apparatus for controlling the flow of liquids and slurries - Google Patents

Abstract

800,072. Automatic flow control systems. VICKERY'S, Ltd., and BARDING, E. April 25, 1955 [May 27, 1954], No. 15696/54. Class 38 (4). [Also in Groups XXIX and XXXVII] In a system for automatically controlling the rate of flow of liquid or slurry upwards through a tube, movement of a float within the tube relative to a pair of vertically spaced elements outside the tube electrically controls a valve adjusting the rate of flow. In Fig. 1 slurry is pumped through valves V4, V3 and upwards through a vertical pipe A. Within pipe A a venturi is formed by a sleeve 13 having V-shaped notches so that a suitably weighted plastic float E carrying an iron ring remains in the neutral position shown when the rate of flow of slurry has the desired value. If the rate of flow varies, movement of the float in a corresponding sense increases the inductance of a coil C1 or C2 so that the outputs of transformers T1 and T2 are unbalanced to operate a D.C. differential relay 17 and thus energize a relay R2 or R1. This in turn energizes a solenoid-operated valve VI 1 or V2 to increase or decrease the pressure applied to the pneumatically operated valve V4 and thereby close or open it to the extent necessary to correct the rate of flow. Valves 44, 45 may be set manually to determine the rate of change of pressure-operating valve V4 or they may be respectively adjusted automatically in dependence on the coil currents of differential relay 17. The characteristics of the control system may be adjusted by alteration of the shape of sleeve 13, by alteration of the spacing of coils C1, C2 and by alteration of the weight of float E. The construction of the float, differential relay and valves is described. Arrangements in which the float differentially controls electromagnetic or electrostatic couplings are referred to. Operation of valve V3 by a reversible servomotor is also referred to.