| 摘要 |
<p>A drain valve of an air braking system for vehicles has a drainage piston (54), a main sump (59) and auxiliary sump (61). Moisture passes from the main sump (59) to the auxiliary sump (61) in response to pressure at a signal port (27) which closes off air supply through ports (24, 26). A reduction in pressure at signal port (27) causes the ports (24, 26) to be reconnected and allows moisture to be expelled through drainage outlet (48).</p> |
