| 摘要 |
<p>A centrifugal pump comprising a pump body (1) housing an impeller (3) keyed onto a motor shaft (4) and provided with a suction mouth (7) and a discharge mouth (8) capable of being made to communicate with, respectively, a suction pipe (9) and a discharge pipe (10). Between the suction mouth (7) and the suction pipe (9) there is provided a chamber (22) that communicates with a tank (11) situated at a level higher than the level of the pump, said tank being interposed between the discharge mouth (8) and the discharge pipe (10) and in communication with both of them and communicating also with the chamber (22) through a recirculation duct (28) having a section smaller than the section of the suction pipe (9). Between the tank (11) and the chamber (22) there is also provided means (13) for cutting off the flow that are controlled by the pressure existing in the tank to automatically cause the liquid to be recirculated in the tank to automatically cause the liquid to be recirculated through the chamber 822) and into the pump whenever the pressure in the tank drops below a predetermined value.</p> |
