| 摘要 |
PURPOSE:To linearly control a gas output without being influenced by a temperature, by controlling the back pressure of a diaphragm which is diaplaced by the relation between gas pressure and back pressure, by changing the on/off time of a solenoid valve, or the period. CONSTITUTION:A disphragm 1 is provided with a main body valve 5 connected so as to be interlocked, and executes the opening and closing control of a valve port 4 to a gas inflow port 7 and an outflow port 3. On the passage to a back pressure chamber 13 of the diaphragm 1, a solenoid valve 9 for externally controlling the back pressue is provided, and the back pressure of the diaphragm 1 is controlled linearly by changing the on/off time of the solenoid valve, or the period. When a valve hole 11 of the solenoid valve is closed, a small flow rate flowing in a by- pass orifice by which the small flow rate is set flows into the back pressure chamber 13, and minimizes the flow rate by minimizing the back pressure. When the solenoid valve 9 is left opened, comparatively plenty of gas flows in from the valve hole 11, the back pressure becomes maximum, the valve port 4 is large opened, and the flow rate becomes maximum. The intermediate flow rate turns on and off the solenoid valve, but removes pulsation of the flow rate by delaying the time of the flow rate by means of an orifice hole 15 and throttle valves 17, 18. |
