| 摘要 |
PURPOSE:To prevent wrong operation in a valve monitor from occurring, by taking 'AND' between a threshold value of a signal level and a time variation of the signal level of an output signal out of a vibro-detector installed in a valve gear. CONSTITUTION:The detection signal obtained out of a vibro-detector 11 installed in a valve gear 1 is made to find a square mean value at a signal extractor 12, and at the next comparator circuit 14, is compared with a preset threshold value alpha in time of valve opening and that whether the valve is in a state of being opened or not is judged. At a gradient calculation circuit 15, either positive or negative in a variation of the said detection signal per unit time is discriminated whereby whether the valve is in a state of being opened or not is judged. A comparator circuit 16 calculates 'AND' of each output of a comparator circuit 14 and the gradient calculation circuit 15, and if the result is one that shows the valve opened state, the effect is displayed on a warning displayer 18. |
