| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an improved pump unit of pressure increase type comparatively simply designed and having excellent operational reliability which has a long service life and is applicable to whole casting method and metal ordinaraily. SOLUTION: A suction part in a container is disposed at the bottom part of the pump unit 1, and a valve menas is disposed in the container and openes or closes the suction port and a delivery port alternatively. A sucking and pressurizing system 40 is composed of a vacuum tank 42, a pressure tank 43, a vacuum pump/pressurizing machine unity 41 connecting these tanks and a closing circuit 49 containing the valve means and further, is connected with a chamber in the container through a conduit pipe 50. Then, a control system 19 is constituted so as to connect or disconnect the vacuum tank 42 with or from the pressure tank 43 alternatively and also, in or subtantially in synchronism with the above connection or disconnection to open or close the suction port and the delivery port alternatively.</p> |
