| 摘要 |
<p>1,212,378. Centrifugal pumps. WORTHING- TON CORP. Nov.14, 1967 [April 18, 1967], No.51732/67. Heading F1C. [Also in Division F2] A self-priming pumping system has a centrifugal pump 12, Fig. 1, arranged inside a well 14 as shown or externally of a liquid storage tank (224), Fig. 7 (not shown), to draw liquid from the well or tank and discharge it through a line containing a liquid accumulator 22. Should the pump lose its prime, a by-pass valve 74 (see Division F2) is opened to permit liquid to pass from the accumulator down into the well to re-prime the pump and expel air or vapour from the well through a line 68 containing a non-return valve 70. The valve 74 may be controlled automatically by the liquid pressure in the accumulator either directly or through a fluid servomotor system, Fig. 4 (not shown). The valve may additionally be associated with an external pressure by which it can be manually or automatically controlled. The valve may be actuated by a solenoid energized through a switch controlled by the liquid pressure in the accumulator, Fig.5 (not shown), or by the liquid level in the well, Fig. 6 (not shown). The switch may be selectively by-passed to provide remote control of the solenoid.</p> |
