| 摘要 |
<p>A process gas controller (2), connected to sources of purging and process gas (20 and 10), includes five valves (24, 28, 30, 32, and 40) and a pressure regulator (8) between the process gas source (10) and the equipment (18). Operating the valves (24, 28, 30, 32, and 40) provides process gass to the equipment (18) and allows the controller (2) to be vented of process gas and purged using the purging gas. A novel pneumatic valve controller (4), used to control the opening and closing of the valves (24, 28, 30, 32, and 40), provides seven different valving combinations to supply process gas to the equipment (18), vent process gas and purge the system. The valve controller (4) includes a program member (52) having a number of passageways (62a-62e), each connected to one of the valves (24, 28, 30, 32, and 40) and to a program surface (74) via program ports (96). A movable valve selection member (54), overlies the program surface (74) and includes an inlet passage (94) coupled to a compressed source (48) so that when the inlet passage (94) becomes aligned with one of the various sets of program ports (96), compressed air is provided to the corresponding valves (24, 28, 30, 32, and 40) to actuate them.</p> |
