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Pneumatic Diaphragm Regulating Valve

Pneumatic Diaphragm Regulating Valve

Valve Body Structure (Two Main Parts)

1. Upper Part: Pneumatic Diaphragm Actuator (Diaphragm Head)

• Diaphragm: Rubber/Fluororubber, generates thrust under pressure

• Spring: Resets and balances air pressure (multi-spring structure is more compact)

• Push Rod: Connects the diaphragm and valve stem, transmits linear motion

• Bracket: Connects the valve body

2. Lower Part: Valve Body Adjustment Mechanism

• Valve Body: WCB, 304, 316, etc.

• Valve Core/Seat: Controls the flow area

• Valve Stem/Packaging: Seals against leakage

• Common Valve Body Types:

◦ Single-seat valve: Low leakage, high precision

◦ Double-seat valve: Low unbalanced force, suitable for large pressure differentials

◦ Sleeve valve: Stable, noise-reducing, erosion-resistant

◦ Angle valve: Anti-clogging, suitable for slurries and crystallizing media
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Product Description

Working Principle

 

1. Signal Input: The control system (DCS/PLC) outputs a 4~20mA electrical signal.

2. Positioner Conversion: The valve positioner converts the electrical signal into 0.02~0.10MPa air pressure.

3. Diaphragm Drive: Air pressure pushes the diaphragm, compresses the spring, and drives the push rod/valve stem/valve core to move.

4. Flow Regulation: The valve core displacement changes the gap with the valve seat, controlling the medium flow rate.

5. Force Balance: Air pressure thrust = spring reaction force + medium force, stabilizing the valve position.

 

Key Characteristics

 

1. Operating Mode (Safety Mode)

• Air-to-Open (FC): Opens with air pressure, closes without air pressure (preferred for fuels and hazardous media)

• Air-to-Close (FO): Closes with air pressure, opens without air pressure (preferred for cooling water and venting)

2. Flow Characteristics (Determined by Valve Core Shape)

• Linearity: Stroke is proportional to flow rate (stable load)

• Equal percentage: Small opening, slow adjustment; large opening, fast adjustment (most commonly used, suitable for temperature/pressure control)

• Fast opening: Small opening, rapidly maximizes flow (on/off control)

 

Applicable operating conditions

 

• Chemical industry: Reactors, distillation columns, pipeline flow/pressure regulation

• Petroleum industry: Crude oil transportation, oil-gas separation, heating furnaces

• Power industry: Boiler feedwater, desuperheating and pressure reduction, flue gas desulfurization

• Metallurgy: Hot blast stoves, water treatment, blast furnace gas

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Related Products

Electric Single-Seat Regulating Valve

Electric Single-Seat Regulating Valve

Core Structure

• Electric Actuator: Servo motor + reduction gear + position feedback, converting electrical signals into linear thrust, with manual operation.

• Valve Body Assembly:

◦ Single valve core + single valve seat (single seat structure)

◦ Valve stem, valve cover, packing seal

◦ Straight-through flow path, moderate flow resistance

Working Principle
1. Control system (DCS/PLC) outputs a 4~20mA signal.
2. The actuator receives the signal and drives the valve stem to raise and lower the valve core.
3. Changing the flow area between the valve core and the valve seat adjusts the medium flow rate.
4. Position feedback forms a closed loop, ensuring the opening degree is consistent with the signal.

Three-Way Regulating Valve

Three-Way Regulating Valve

Basic Structure and Types

Based on valve core structure, there are two main types:

1. Confluence Type Three-Way Valve (Two Inlets, One Outlet)

• Two inlets, one outlet

• Mixes two different temperatures/mediums before outputting

• Mostly used for temperature control of hot and cold fluids

2. Diverter Type Three-Way Valve (One Inlet, Two Outlets)

• One inlet, two outlets

• Diverts one flow path proportionally to two pipelines

• Mostly used for bypass regulation and flow distribution

Common Actuators:
• Pneumatic Diaphragm Type (Most Common)

• Electric Actuator (Electric Three-Way Control Valve)

• Can be equipped with a positioner to achieve 4–20mA automatic adjustment

Pneumatic Regulating V-Type Ball Valve

Pneumatic Regulating V-Type Ball Valve

Working Principle

1. The ball core has a V-shaped notch, and the valve stem drives the ball to rotate 0-90°;

2. A wedge-shaped throttling channel is formed between the V-shaped notch and the valve seat. As the rotation angle changes, the flow cross-sectional area changes synchronously;

3. When paired with a pneumatic valve positioner, it receives 4-20mA analog signals to precisely control the opening degree, achieving continuous regulation of pressure, flow rate, and liquid level;

4. When closed, the V-shaped notch fits tightly against the valve seat, achieving reliable shut-off.

Self-Regulating Valve

Self-Regulating Valve

Working Principle
• No compressed air or power supply required.
• It directly utilizes the pressure, pressure difference, and temperature of the medium itself as power.
• This drives the internal actuator of the valve, automatically maintaining the pressure/temperature within the set range.
• Simple structure, maintenance-free, and long-term stable operation.

+86 19858780995

+86 19858780995

+86 19858780995

+86 19858780995

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