PO check valves (PO checks) are used to hold pressure in a cylinder in the event of a drop in line pressure, total loss of pressure, or loss of power to the control valve
The valve locks air in a cylinder until the pilot signal is energized, at which time the valve opens and air evacuates the cylinder
PO checks are normally closed valves that can be held open by application of an external pilot pressure signal
The PO check can be opened with an optional manual override button:
Buttons are sometimes required by application, as a way to safely release trapped air
Standard (extended) buttons and flush buttons are available
Where are PO Checks Used?
NGT’s PO checks can be used in any pneumatic application where a sudden drop in pressure would harm personnel, damage products, or otherwise hinder the manufacturing process
Typical applications of PO checks are:
Clamping
Work holding
Lifting equipment, doors, platforms, and material
Pilot signal to open valve typically comes from:
For single acting cylinders, another port on the control valve
For double acting cylinders, the other side of cylinder
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