| 摘要 |
PURPOSE:To aim at economic prevention, for pump overheating by setting up escape piping for overheat prevention use and a solenoid valve in a pump discharge line, while controlling the solenoid valve so as to release a minimum necessary flow of liquid discharge in proportion to the discharge line's flow and pressure. CONSTITUTION:A flow signal Qi and a pressure signal Hi of the pump discharge line are inputted into an arithmetic unit and, if the status satrsfied Hi>=alphaQi<2> (alpha:constant), a solenoid valve installed in escape piping for overheat prevention is fully opened and afterward when the operated value comes to satisfy Hi<=beta Qi<2> (beta:constant), the solenoid valve is fully closed but it keeps up a fully opened state until this time. In this connection, when Hi>=alphaQi<2> is not satisfied the solenoid valve is left intact without being fully opened switching control takes place with the following result of calculation, Hi<=betaQi<2>. |
