| 摘要 |
<p>A pump circuit employs a safety device (11) to shut down power to a pump (12) in the advent of adverse pressure conditions existing in the pump circuit. The pump circuit includes a pump inlet conduit (13) communicating with an inlet (14) of the pump (12), an outlet conduit (13) communicating with an outlet (16) of the pump (12), a pump inlet pressure sensing line (17) and a pump outlet pressure sensing line (18). The sensing lines (17, 18) are coupled to a power shut down control unit (19) which is connected in series with the power supply to the pump (12) through power lines (20 and 21). As long as the pressure upstream or downstream of the pump (12) remains normal, power to the pump (12) will be maintained by the control unit (19). Should the pressure sensed vary beyond predetermined limits, then power to the pump (12) would be shut down by the control unit (19).</p> |
