Function of a Bi-Directional Pilot Operated Check Valve (Blocking Valve)

A bi-directional pilot operated check valve, also known as a blocking valve, is a type of flow valve used in pneumatic and hydraulic systems. It offers several unique functionalities:

• Bi-directional: Unlike standard check valves that only allow flow in one direction, these valves can control flow in both directions. This is achieved by using a separate pilot signal to actuate an internal check element.
• Blocking: When no pilot signal is present, both flow directions are blocked, essentially "locking" the flow path. This prevents pressure loss or unintended movement in the system.
• Pilot Controlled: Applying a pilot signal to a designated port opens the internal check element in the desired direction, allowing controlled flow. The pilot pressure required is typically lower than the main system pressure.

Applications:

• Securing Pneumatic Cylinders: These valves are commonly used to hold the position of pneumatic cylinders when not actively extended or retracted. This prevents movement due to pressure fluctuations or external forces.
• Preventing Backflow: In circuits with multiple actuators, they can prevent backflow from affecting other components while isolating specific sections.
• Safeguarding Equipment: Blocking valves can enhance safety by ensuring equipment or actuators remain stationary during maintenance or unexpected shutdowns.

Advantages:

• Increased Safety: The blocking function improves safety by preventing unintended movement or pressure loss.
• Enhanced System Performance: These valves can optimize performance by isolating sections, directing flow efficiently, and preventing backflow issues.

Please note: This description is for general understanding and specific functionalities may vary depending on the specific Camozzi VBO & VBU models you are considering. It's always recommended to refer to the manufacturer's datasheet for detailed specifications and performance information.

 

A uni-directional pilot-operated check valve essentially combines the functions of a regular check valve with an external control mechanism. Here's a breakdown:

Regular Check Valve:

• Allows flow in one direction (typically the higher pressure side) and blocks flow in the opposite direction.
• Operates automatically based on pressure differential across the valve.

Pilot-Operated Check Valve:

• Adds a separate "pilot" port that allows independent control of the main valve.
• When pilot pressure is applied, it overrides the internal pressure mechanism and allows flow in the normally blocked direction.
• When pilot pressure is off, the valve functions like a regular check valve again.

Uni-Directional:

• In this specific case, the valve only allows flow in one direction even when pilot pressure is applied.
• This means the pilot only unlocks the valve, it doesn't enable flow in the opposite direction.

Therefore, a uni-directional pilot-operated check valve:

• Prevents flow in one direction (typically the lower pressure side) regardless of pressure.
• Allows controlled flow in the opposite direction (higher pressure side) by applying pilot pressure.
• Offers flexibility in controlling flow and preventing backflow in specific applications.

Here are some key features and benefits:

• Prevents unintended flow reversal: Useful for protecting equipment or maintaining pressure in a system.
• Controlled release of pressure: Enables controlled venting or draining of fluids when needed.
• Remote operation: Pilot pressure allows for remote control of the valve operation.
• Compact and versatile: Available in various sizes and materials for diverse applications.

Overall, uni-directional pilot-operated check valves provide a reliable and controllable solution for preventing backflow and managing flow direction in systems requiring precise control.