An Electrical Device for Measuring the Flow of Fluids in Pipes

Abstract

Abstract This paper deals with the theory and experimental development of an electrical device in which an ammeter and watt-hour meter are utilized in measuring the flow of fluids in pipes. The electric current which is used is regulated by the differential pressure of the fluid passing through the pipe. The principle of the device involves a combination of the physical laws governing the flow of fluids in pipes and the flow of an electric current. The units of flow measurement are represented by general equations covering the relation between the velocity of the fluid in the pipe and the differential column obtained by the device. For the units of the electrical measurement, in the standard adopted the maximum capacity of flow is represented by a current of 1 ampere at a constant pressure of 40 volts. The diagrammatic relation of the units involved in the electric measurement of the flow is shown by two curves; one in the form of a parabola representing the relation of differential head to the current — the other in the form of a hyperbola representing the relation between the current and the corresponding resistance in the circuit. A summary is given of the experimental work in preparing a resistance which would vary according to the relation established, and which would operate under the usual conditions of flow. Particulars are given of the early experimental devices and of the improvements made until a satisfactory model was obtained, and the method of testing is discussed and a typical run described in detail. In conclusion, a number of instances are cited where the instrument described has made possible the adoption of central measuring stations in large manufacturing plants, resulting in improved economy of operation.