| 摘要 |
PURPOSE:To prevent entaglement or choking of pump even when used for suction/discharge of mud by constructing such that liquid is fed from supply source not through a pump but through a storage tank to the liquid deivery port through operation of four-way valve. CONSTITUTION:When sucking liquid from supply source, it is sucked through a suction port 1a into a liquid storage tank 1 by means of a vacuum pump 2 and a four-way valve 9. While when discharging liquid, a gate valve 7a at the liquid suction port 1a is closed while a gate valve 7b at the liquid delivery port 1b is opened to lead the open end of liquid discharge port (not shown) coupled with said port 1b to predetermined discharge place, then the pump discharge port 2b and liquid storage tank 1 are communicated through operation of four- way valve 6 and the vacuum pump 2 is driven under the state where the pump suction port 2a is communicated to the atmosphere thus to deliver liquid in the storage tank 1 through liquid delivery port 1b. With such arrangement, entaglement of solid material or choking of pump can be prevented even when used for suction/discharge of mud. |
