| 摘要 |
<p>An automatic drain valve for discharging accumulations of condensables and foreign materials from a pneumatic system. The drain valve (10) comprises a reservoir (14) defining an inlet (30) and an outlet (86) for flow-through communications with a pneumatic system. A pilot valve (41) is mounted in the reservoir (14) for selectively communicating pressurized air to a valve operator (57), such that the valve operator selectively opens and closes a drainage valve (82) communicating with the outlet (88) of the reservoir (14) for selective draining the reservoir. The pilot valve (41) includes a sensor tube (42) which defines a valve seat (44) and includes a magnetized valve plug (46) for selectively engaging the valve seat (44), the valve plug (46) having a selected magnetic polarity. A level sensing float (52) disposed within the reservoir (15) carries an annular magnet (56) normally having a polarity opposite that of the valve plug (46) such that the annular magnet (56) acts upon the valve plug (46) selectively opening and closing the pilot valve (81) as the float (52) rises and falls from a raised position to a lower position with the level of liquid within the reservoir (14).</p> |
