| 摘要 |
PURPOSE:To shorten the switching time of a reverse washing valve and to prevent the lowering of the efficiency of a plant by a method wherein when the operation condition of the reverse washing valve is switched, the reverse washing valve is initially rotated at high speed and then the rotational speed of the valve is slowed down. CONSTITUTION:The condenser 1 is provided with a condenser vacuum degree detector 20 whose output signal is inputted to a control signal generator 22 which generates a control signal to a reverse washing valve drive device 21. Further, the reverse washing valve 10 is attached with a valve position detector 23. When a valve body 16 of the reverse washing valve 10 opens to exceed its medium opening degree, a signal is generated from the detector 23 so as to be applied on the control signal generator 22 and the reverse washing valve drive device 21 is controlled by the output signal of the control signal generator 22. The reverse washing valve 10 is operated at high speed at which the vacuum degree of the condenser becomes lower than the plant trip limiting vacuum, until the valve body 16 opens to exceed its medium opening degree and the vacuum degree of the condenser exceeds a predetermined value at the time of switching the valve 10 and afterwards, the valve 10 is operated at a comparatively low speed at which no water hammer phenomenon takes place in the condenser so that the switching time of the valve 10 is shortened and the lowering of the efficiency of the plant is prevented. |
