GB529615A - Improvements in means for electrically indicating instantaneous values of a variablesuch as rate of fluid flow - Google Patents

Abstract

529,615. Measuring fluid flow. LEMMENS, F. J. G., (Representative of Lemmens, G. J. F.), June 5, 1939, Nos. 16432, 31229 and 31230. [Class 40 (i)] [Also in Group XXVI] In a fluid meter, a bladed impulse wheel and its casing are made of non - magnetic material with the exception of two diametrically opposite wheel blades 30, Fig. 1, and two fixed guide vanes 34. The guide vanes are the pole pieces of an electromagnet 44, Fig. 4, outside the meter casing and the rotation past them of the two blades of magnetic material produces current pulses in the magnet windings which are used to secure the rotation of a ratchet toothed wheel 52 of an indicating or registering device. In the normal condition, the driving magnet of the registering device is energized via its winding 70 and self-operated springs 74, 76, the circuit of electromagnet 44 is completed via springs 78, 80, and the driving pawl 54 is in its highest position. When the magnetic blades pass the guide vanes, the impulse induced in winding 46 on electromagnet 44 de-energizes the driving magnet and the pawl drops, breaking the contact between springs 74, 76 to complete the de-energization and finally dropping behind the next tooth and allowing the springs 74, 76 to close again. The driving magnet is thus re-energized and the pawl drives the ratchet wheel one step. During the relapse of the driving magnet, the electromagnet 44 is disconnected and a third winding on the driving magnet is shortcircuited to delay its re-energization. By this means, electromagnet 44 is not connected up until the magnetic blades are clear of the guide vanes, and no load is put on the fluid meter.