GB555710A - Improvements in electric switches for motor-driven pumps - Google Patents

Abstract

555,710. Regulating delivery of pumps ; switches held set and freed mechanically. ELECTRICAL APPARATUS CO., Ltd., and WALTON, J. R. July 16, 1942, No. 9892. [Class 102 (i)] [Also in Group XXXVII] In an arrangement wherein a pump is driven by an electric motor and the operation of a valve in one or more delivery lines of the pump also operates a switch to start and stop the motor, the switch has a delayed opening action so that repeated closing or opening of the valve for "topping up" purposes does not cause a corresponding repeated stopping and starting of the motor. The valve is controlled by a pivoted lever (not shown) which also is arranged to actuate two push rods 12, 13, pushing one in while the other is released. The rod 12, when pushed in, turns a bell-crank lever 19 into the position shown in which a contact 30 spring-supported on a horizontally-moving bar 20 engages fixed contacts 29 and the motor is started. The lever 19 is held in the position shown by a latch 23. When the valve is closed, rod 13 is pushed in and the latch 23 released, allowing the parts 19, 20 to move slowly to the left under the restraining influence of clockwork 36, so that the contacts 30, 29 are not opened till after a time interval. An emergency switch 37, 50, adapted to stop the motor by operation of a hand lever 39 projecting from the casing, may also be provided. The lever 39 when moved to the right depresses contact spring 50 and releases contact spring 37 which moves to the left. Resetting can only be effected by removing the cover 41 and actuating a push button 42.