| 摘要 |
<p>A changeover valve (100) comprises a first valve member (20) and a second valve member (50). The first valve member (20) has an aperture (28). The second valve member (50) has first and second apertures (54, 58). The first valve member (20) is movable relative to the second valve member (50) for selective alignment of the first valve member aperture (28) with one or other of the apertures (54, 58) of th e second valve member (50). The valve (100) also has a ramp and follower means (29, 6 2) for automatically moving the valve members (20, 50) away from the one another during changeover movement of the first valve member (20) relative to the second valve member (50) so that wear on the surfaces of the valve members (20, 50) is minimised .</p> |
