Pneumatic flow cONROL VALVES : TECHNICAL VALVES

1. Speed Control Valve (One-Way Flow Control Valve)

Description: Regulates the speed of pneumatic cylinders by controlling the flow of air. It provides adjustable flow in one direction and free flow in the reverse direction via an integrated check valve.

Technical Specifications:

• Port Sizes: Rc(PT) 1/8, 1/4, 3/8; M5
• Tube Connections: Push-in for Φ4, Φ6, Φ8, Φ10, Φ12 mm
• Flow Adjustment: Precision needle valve with spring-loaded mechanism for fine, stable control.
• Knob: Ergonomically designed with a locking mechanism to prevent vibration-induced drift.
• Flow Capacity: Specified by Cv value (e.g., 0.1 to 1.5 depending on size).
• Free Flow Check: Integrated ball check valve for unrestricted reverse flow.
• Body: Brass, Nickel Plated.

Common Types:

• Inline Type: Installed directly in the line.
• Panel Mount Type: Designed for mounting in a control panel.
• With Push-in Fittings (Integrated): Combines the valve and fitting into a single compact unit.

2. Needle Valve

Description: Used to precisely throttle or shut off airflow. Unlike a speed control valve, it restricts flow in both directions, making it suitable for general flow regulation, bleeding, or precise shut-off applications.

Technical Specifications:

• Port Sizes: Rc(PT) 1/8, 1/4
• Tube Connections: Push-in for Φ4, Φ6, Φ8 mm
• Flow Adjustment: Fine-pitched needle and seat for precise metering.
• Handle: Knurled knob or screwdriver slot for adjustment.
• Flow Capacity: Lower Cv than equivalent flow control valves due to finer metering.
• Function: Bi-directional flow restriction.
• Body: Brass.

Common Types:

• Straight Pattern
• Angle Pattern
• Panel Mount Type

3. Pressure Control Valve

Description: This category includes Relief Valves and Sequencing Valves.

• Relief Valve: Protects the system by exhausting air when a preset pressure is exceeded.
• Sequence Valve: Supplies output pressure only after a preset inlet pressure is reached, used for controlling the sequence of operations.

Technical Specifications:

• Port Sizes: Rc(PT) 1/8, 1/4
• Pressure Adjustment Range: Typically 0.05 to 0.8 MPa (adjustable via spring).
• Adjustment Mechanism: Spring-loaded diaphragm or piston. Adjusting knob with lock nut.
• Accuracy: Hysteresis is minimized for stable and repeatable operation.
• Exhaust Port: Integrated port for relief function (often can be fitted with a silencer).
• Body: Brass.

Common Types:

• Manual Reset Relief Valve: Requires manual intervention to reset after actuation.
• Adjustable Sequence Valve.
• Pressure Regulator (a primary type of pressure control valve

4. Check Valve (Non-Return Valve)

Description: Allows airflow in one direction only and blocks flow in the reverse direction. Essential for maintaining pressure in circuits, preventing backflow, and enabling logic functions.

Technical Specifications:

• Port Sizes: Rc(PT) 1/8, 1/4, 3/8
• Tube Connections: Push-in for Φ4, Φ6, Φ8, Φ10, Φ12 mm
• Cracking Pressure: Very low (~0.01 MPa), allowing free flow in the forward direction with minimal pressure drop.
• Sealing Mechanism: Poppet (for low leakage) or Ball (for quick response).
• Seal Material: NBR.
• Leakage: None in reverse direction at rated pressure.
• Body: Brass.

Common Types:

• Inline Check Valve: Standard straight-through design.
• Shuttle Valve (OR Valve): Allows flow from either input to a common output.
• Quick Exhaust Valve: Exhausts air directly from the cylinder port for rapid retraction.

5. Silencer (Muffler)

Description: Reduces exhaust noise from valves and cylinders. Works by diffusing the exhaust air stream through a porous material (sintered metal or plastic), which dampens sound energy.

Technical Specifications:

• Thread Size: Rc(PT) 1/8, 1/4, 3/8, 1/2
• Noise Reduction: Typically reduces noise by 15 to 35 dB(A), depending on model, size, and pressure.
• Element Material: Sintered Bronze (standard, for high heat resistance) or Sintered Plastic/Polycarbonate (for lower cost and corrosion resistance).
• Pressure Drop: Minimal effect on exhaust flow, ensuring minimal impact on cylinder speed.
• Body/Cap: Brass or Engineering Plastic.
• Optional Features: Built-in speed control function (needle valve) to create a compact exhaust control unit.

Common Types:

• Standard Small Silencer: For individual valve exhaust ports.
• Large Capacity Silencer: For main exhaust lines or large-volume exhausts.
• Speed Control Silencer: Combines a silencer with an adjustable exhaust throttle.
• Panel Mount Silencer.