| 摘要 |
<p>A solenoid valve (27) has an energising coil (40) for a shuttle (41) arranged to control movement of a valve member (28) relative to a valve seating (25) to open and close an outlet port (24). The shuttle (41) includes a permanent magnet (42) arranged to generate a repulsion force when the coil (40) is energised for displacing the shuttle (41) against the biassing of a return spring (48) to move the valve member (28) away from the valve seating (25) to open the outlet port (24), and displacement of the shuttle (41) is adjustable by varying the energising voltage to provide a range of open positions of the valve member (28) for controlling the flow rate. The valve (27) is preferably incorporated in a flow control device (1) including a flowmeter (9) for monitoring the flow rate and generating a signal related to the flow rate for adjusting the energising voltage to maintain a selected flow rate substantially constant.</p> |
