| 摘要 |
<p>The double seat valve has an inlet (9) and outlet (10) separated by the valve seat (3) and piston valve (7). The valve piston has an inner seat (37) sealed by the valve head (32) attached to the actuating rod (8). A helical coil spring (44) tends to lift the valve head (32) off the seat (37). With the piston valve (7) on its seat (3) the coned disc spring (47) tends to push the valve head (32) on to the seat (37) with a force greater than that of the coil spring (44). When the rod (8) is lifted upwards to open the inner valve (32), in order to open the main valve (7), the coned disc spring is deflected past its neutral position and then exerts an upward force which keeps the inner valve open.</p> |
