| 摘要 |
PURPOSE:To make it possible to minimize the transitional variation of the level of water in a condensate head tank by a method wherein in addition to the conventional control of a flow rate adjust valve according to the level of water in the condensate head tank, the flow rate adjust valve is precedingly controlled by detecting the variation of the flow rate of water in a condensate purification system according to the signal from a flow rate detector procived midway in a pipe extending from a condensate purification device to the condensate head tank and a second hot-well. CONSTITUTION:The output (h) of a water level detector 13 for a condensate head tank is compared to a predetermined output value (hO) and the flow rate adjust valve 11 is constantly controlled by the output signal from a proportional integrating operator 14a corresponding to the difference between the output values (h) and (hO). That is, the output signal Q from the flow rate detector 9 is usually constant and does not change. However, when the flow rate detected by the flow rate detector 9 varies at the time of tripping a single condensate purification pump, a differential operator 14b detects the rate of variation (q) corresponding to the variation of the flow rate and the variation of the flow rate is precedingly controlled through an adder 14c. In short, the flow rate adjust valve 11 is choked a little earlier in response to the abrupt lowering of the output signal Q of the flow rate detector 9 to thereby prevent the lowering of the level (h) of water in the condensate head tank. |
