GB871172A - Delivery restricting equipment for use with pumps - Google Patents

Abstract

871,172. Dispensing liquids. SLADEN, C. B. Sept. 30, 1959 [Sept. 30, 1958], No. 31116/58. Class 116 An electronic timing device cuts off the delivery of a petrol pump after a period corresponding to a predetermined maximum delivery. When the pump is out of use a capacitor Cl is charged and renders a pentode VP non-conductive. When the pump 10 is taken into use, a switch 11 is closed to complete a circuit through a high resistance transformer primary Tl, the current being insufficient to operate the pump motor. The current induced in a low resistance secondary operates a bridge circuit to actuate relay L/2 which closes contacts L2 to prepare the pump operating circuit and closes contacts L1 to discharge capacity Cl, rendering pentode VP conductive which energises relay K/3 to close contacts K3 and open contacts K2, whereby the pump motor starts operating. Simultaneously relay KK/1 opens contacts KK1 to break the discharge circuit of capacity C1 which starts to recharge. After a predetermined time interval, corresponding to the maximum permitted delivery, the charge on capacity C1 reaches a value to render VP non-conductive which deenergises relay K/3 to open contact K3 and close contacts K2 whereby the pump motor stops automatically if it has not already been stopped by the operator. Relays L/2 and KK1 remain energised, however, so that capacity C1 cannot be discharged to render the pump operative again until relay L/2 has been released by opening of the operator's switch 11.