2 Way Air Pilot Operated Valves

What is pilot operated?

Pilot operation is the main force required to open the valve is provided by the media pressure. The pilot can be very small as it only controls the flow of a small diameter impulse line that allows the fluid to open the main diaphragm or piston.

What does 2 way mean?

2 Way or 2 port air operated valves refer to the line connections in that there is a single inlet and outlet which makes them ideal for flow isolation. For most of these valves, the flow direction through the valve must be from the inlet to the outlet as reverse flow will cause the valves to fail or operate unreliably.

Depending on the model, 2 way pilot operated valves are used with liquid or gaseous media and can incorporate many varieties of options:

• Functional – normally open or normally closed
  
• Feedback – limit switches, visual position indicators
  
• Various elastomers for compatibility with a wide range of gases and liquids 
  

Normally closed or normally open?

In valve terms:

• Normally closed means that the valve is shut and fluid cannot flow from the inlet to the outlet. When the pilot pressure is applied, the internal valve parts move and the media flows from inlet to the outlet, as long as the pressure is higher at the inlet.
  
• Normally open means that the valve is open and fluid flows from the inlet to the outlet when the pressure at the inlet is higher than the outlet. When pneumatic pressure is applied to the pilot, the internal valve parts move and the valve will close.
  

Most air operated valves will only stay in the applied pilot pressure position while the pilot pressure exists. They will revert to the rest position as soon as pilot pressure is removed.

View 2 Way Pilot Operated Valves