| 摘要 |
<p>PURPOSE:To miniaturize a device, raise its reliability and make it possible to simplify construction by simplifying a signal transmission system while constructing a valve opening and closing control part with semiconductors and uniting the control part and a valve driving part in a body. CONSTITUTION:A valve opening detection part 13 provides reference voltage by making use of resistance 14 and a constant-voltage element 15, said reference voltage is constituted by a serial resistance circuit comprising variable resistance 16, 17, 18, and a lower voltage value divided by said resistance circuit is outputted to a valve opening and closing control part 21 as the upper limit value 19 of a valve-open state and a higher voltage value outputted as the lower limit value 20 of a valve closed state. And, the valve is operated in its opening derection by an output signal from a comparator 22 and in its closing direction by the output signal from a comparator 24. The valve is driven for its opening and closing by a valve driving part 39, and by opening and closing the valve with switches 40, 41 regardless of the control part 21 care at construction and maintenance is taken.</p> |
