Seek the principle of the shut-off valves 78-80H / 08-80H of MASoneillan

Design valves according to process requirements!

The Masoneillan 78-80H and 78-80S are three-way switching valves with \"adjustable set pressure\"; the side port of these switching valves becomes blocked, turning it into a two-way port. These models can be used as locking valves. The lock valve is used as a safety device attached to the control valve in the driving position; when a power outage occurs, it shuts off the air supply system that operates the pneumatic control valve until the air pressure returns to its normal level. In my understanding, a lock valve is a position-retaining valve that ensures the valve remains in its original position when the air supply is cut off, until the air supply is restored. Principle: Inside there is a valve plug controlled by a spring; when the pressure of the air supply suddenly drops to the set value, the valve plug closes, ensuring that the air pressure in the actuator remains constant, thus achieving locking. Until the gas supply is restored, the valve plug opens. You can look up the working principle of pneumatic check valves online to learn about it*.