Problem with the check valve installed at the outlet of the locator?
Thread Content
Some of the valve positioners in our factory are equipped with hold-down valves at their outlets, and they are double-acting positioners; when air is released from one outlet, air is also released from the other. But both lines are equipped with air circuit pressure maintaining valves; how does this valve maintain pressure? How is it possible to allow exhaust gas to be released during adjustment, while preventing it from being released in abnormal situations?
When the air supply is normal, the position maintaining valve functions as an open circuit, allowing the actuator signal to reach the cylinder properly. In the event of a gas supply failure, the position holding valve activates to block the air pressure in the cylinder, thereby ensuring that the cylinder maintains its position.
In other words, when there is a loss of air supply, the pressure of air above the holding valve disappears, causing the holding valve to close; as a result, the air in the cylinder cannot escape, thereby achieving the purpose of holding it in place
Everything mentioned above is correct; it’s exactly that thing. If you search the forums, you’ll find that someone has previously posted the schematic diagrams. So-called position control valves and locking valves mean the same thing……
Huh, isn’t a lock valve just a position control valve? What’s the difference? @Wang Tianze
http://bbs.hcbbs.com/thread-1355535-1-1.html It also mentions that a hold-back valve is also known as a locking valve or a stop valve. @Wang Tianze