| 摘要 |
PURPOSE: To make the temperature of secondary side cooling water fit to the temperature of primary side cooling water, by performing temperature control, in the manner in which the reference value of temperature is changed according to the duty of switching time of a solenoid valve on the primary side cooling water supply side of a heat exchanger. CONSTITUTION: A heat exchanger 50 is connected with primary side cooling water FW via a solenoid valve 72. Secondary side pure water CW is made to circulate around the heat exchanger 50, a tank 56 and a chamber 14 by a pump 52. A temperature detection signal St of the pure water CW in the tank 56 is detected by a temperature sensor 64 and a temperature detection circuit 66. The signal St is compared with a reference value Pt. When the signal St is lower than the reference value Pt, the solenoid valve 72 is closed. When St is higher than Pt, the valve 72 is opened. Thus the temperature control is performed, and the reference value Pt is set simultaneously. Firstly, the reference value Pt is set as an initial value P0 , and the duty is obtained on the basis of the switching time of the valve 72. The duty is compared with the previously set value. In the adequate case, the reference value Pt is kept constant. In the high case, the reference value Pt is increased. In the low case, the reference value Pt is decreased. |
