| 摘要 |
<p>An improved relay valve (10) having a supply port (16), a delivery port (18), an exhaust port (20), a control port (17), a relay piston (14) controlling communication between the supply port (16), the delivery port (18), and the exhaust port (20) in response to a pneumatic signal applied to the control port (17) and including a passage (40) extending through the piston (14) to the exhaust port (20) for draining to atmosphere moisture and other contaminants which build up on the top of the piston (14). A diaphragm element (30) having a cylindrical protrusion portion (36) is disposed in the piston (14) above the passage (40) to act as a check valve and seal the passage (40) when a pneumatic signal is applied to control port (17). The diaphragm element includes a top resilient portion (32) which serves as a spring to open the drain passage when no signal is applied to control port (17). Two flat areas (34) are provided on the top resilient portion (32) which prevents the diaphragm element (30) from prematurely sealing the drain hole (40). The cylindrical protrusion (36) keeps the diaphragm element (30) properly aligned in the tapered bore (44) leading to drain hole (40). A retaining ring (42) keeps diaphragm element (30) within the bore (44).</p> |
