METHOD FOR ACTUATING VACUUM PUMP IN VACUUM DRAINAGE SYSTEM

摘要

PURPOSE: To smoothly effect starting by introducing the atmosphere into a suction pipe before starting to make starting torque of a pump smaller than that of a motor. ;CONSTITUTION: A switch 10 is turned on to detect and determine the inner pressure of upper space of a drain tank 3 by means of an inner pressure determining means 11, and when the inner pressure is higher than a set negative pressure value, a vacuum pump 1 is actuated to collect water under vacuum. And when said pressure is lower than said value, a motor-operated ball valve 9 is opened to cause a suction pipe 2 to communicate with an atmosphere introducing port 5a of a silencer 5 with separator through a bypass pipe 7 and exhaust pipe 4, thereby admitting the atmosphere into the pipe 2. Next, after the lapse of a time period set by a timer circuit 12 during which the pressure in the pipe 2 becomes atmospheric pressure, a motor 6 is actuated to start the pump 1. After the start of the pump 1, after the lapse of a second time period set by the timer 12, the valve 9 is opened to effect a predetermined suction and exhaust operation from the tank 3 through the pump 1, the pipe 4 to the silencer 5. As a result, starting can be effected surely with a simple constitution and acceleration characteristics and efficiencies can be improved.;COPYRIGHT: (C)1994,JPO&Japio