| 摘要 |
PURPOSE:To switch smoothly and surely the system from a manual system to an automatic system by holding a water level control valve when the change rate of the water level of a condensate head tank becomes a prescribed value or higher. CONSTITUTION:The water level signal of the condensate head tank which is attained by a water level detector 14 is inputted to a water level deviation adder 33 and a differentiator 35 for attaining the change rate of the water level. When the output value of this differentiator 35 becomes a prescribed value or higher, switches 34a and 34b are broken by a controller 36 which has the function to disconnect the water level deviation of a water level controller 15. Then, the input of a kick signal due to the manual operation to a program signal generator 32 is turned off, and a water level control valve 17 is held in its opening position by the output of the water level controller 15. Thus, the system is switched from the manual system to the automatic system smoothly and surely. |
