| 摘要 |
<p>In a motor working fluid e.g. air, in a supply duct 12 acts on a piston 15 which actuates a valve- member or "disc" 20, which consequently opens an outlet 17 to exhaust e.g. the atmosphere. When the supply duct 12 is shut-off a resilient member 23 lifts the disc 20, which closes the outlet 17 and thus terminates the outlet noise. <IMAGE></p> |
