| 摘要 |
The direct acting pneumatic control circuit is for controlling a dual diaphragm, or double acting cylinder type automatic web guiding system. A control valve (15) is equipped with a follower (18) which follows the web (10) and continually monitors the web position and activates a control valve spool (37) to modulate the flow-exhaust rates to bring the web (10) to a corrected position with no over-run or hunting for position. The palm (18) and its associated rod follow the web when the web is moving away from the palm by a helical spring (40), totally enclosed within the valve body (36), and acting directly on the valve spool (37). In the neutral position inlet (45) is connected to outlets (46,47) and exhaust (36d) closed. |
