| 摘要 |
PURPOSE:To measure a state of stuck scale automatically, highly accurately and continuously by discriminating the scale stuck state on the basis of the evaluation value for concentrated state at prescribed conditions corresponding to the scale stuck state. CONSTITUTION:An evaluation value operating part 8 evaluates the concentrated state of boiler water independently of steam load. A monostable multivibrator MM is triggered at the completion of the evaluation operation and, FF 10e is reset when a complete blow switch 11 is closed at the trailing edge of an output from the monostable multivibrator MM. The opening of an AND gate 10b in a scale stuck state discriminating part 10 is controlled through the MM 10d and the FF 10e and the high level output of a comparator 10c is produced through the gate 10b when the evaluation value corresponding to the scale stuck state calculated by the operating part 8 exceeds a prescribed value just after the boiler water is replaced with fresh water by blowing the steam completely. The stuck scale higher than the prescribed quantity can be automatically, highly accurately and continuously measured. |
