Electric control valve

Product Overview

The Electric Sleeve Control Valve (also known as electric cage control valve) is a sleeve‑guided control valve driven by an electric actuator. It is widely used in automatic control systems across industries such as petrochemical, chemical, power generation, metallurgy, and light industry, particularly for applications requiring high differential pressure, large flow capacity, and low noise. The valve receives a standard analog control signal (typically 4–20 mA or 0–10 V DC). The electric actuator moves the plug up and down inside the sleeve, changing the throttling area through the multi‑port windows of the sleeve to precisely regulate flow rate, pressure, temperature, or liquid level.

The sleeve design offers pressure balance, low noise, anti‑cavitation, high allowable differential pressure, and interchangeable seats. It is especially suitable for steam, gas, and high‑pressure liquid services where noise and cavitation are concerns. The valve features flanged connections, with nominal diameters from DN15 to DN400, pressure ratings from PN16 to PN160 (Class 150–900), and body materials including carbon steel and stainless steel.

Product Structure

The Electric Sleeve Control Valve mainly consists of the electric actuator and the sleeve valve body assembly.

Electric Actuator:

1. Motor: Reversible servo motor or stepper motor providing driving force.

2. Gearbox: Gear or worm‑gear reducer converting high‑speed motor rotation to low‑speed, high‑torque output.

3. Position Feedback Device: Potentiometer or Hall sensor providing real‑time valve position feedback.

4. Control Unit: Receives the external control signal, compares it with the position feedback, and drives the motor to achieve precise positioning.

5. Handwheel Mechanism: Manual override for on‑site commissioning and emergency operation.

6. Limit Switches: Mechanical or electronic limits to protect the valve from over‑travel at fully open/fully closed positions.

7. Terminal Box: For connecting power, control signal, feedback signal, etc.

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Sleeve Valve Body Assembly:

1. Body: Cast or forged body in carbon steel (WCB), stainless steel (CF8/CF8M), etc. Flanged ends conforming to GB/T 9113, ANSI B16.5, EN 1092‑1, etc. Straight‑through flow path.

2. Sleeve (Cage): Cylindrical component with multiple throttling windows, made of stainless steel (optionally hardfaced). The sleeve provides guiding, pressure balancing, noise reduction, and anti‑cavitation.

3. Plug: Balanced plunger‑type plug moving inside the sleeve. The sealing face can be hardfaced with Stellite or covered with PTFE/PEEK. Plug stroke changes the throttling area of the sleeve windows to achieve regulation.

4. Seat: Removable seat forming the sealing pair with the plug, made of matching material.

5. Valve Stem: Stainless steel stem, connected to the actuator output shaft at the top and the plug at the bottom.

6. Packing Box: Contains PTFE or flexible graphite packing, compressed by a packing gland to prevent external leakage.

7. Bonnet: Connected to the body, housing the packing and stem. Available in standard, extension (for high/low temperature), or bellows seal types.

8. Balancing Seal Ring: Installed between the plug and sleeve to reduce internal leakage and improve control accuracy.

Compact construction. The sleeve design minimizes unbalanced forces on the plug, allowing high differential pressure capability.

Function

1. Flow Regulation: By varying the plug stroke, the throttling area of the sleeve windows is changed, enabling precise flow control with linear or equal percentage characteristics.

2. Pressure Balance: The sleeve construction balances the pressure above and below the plug, greatly reducing unbalanced forces. This allows a much higher allowable differential pressure with a smaller actuator.

3. Noise Reduction & Anti‑Cavitation: The multi‑port sleeve breaks high‑velocity flow into multiple small streams, reducing turbulence noise and vibration. At the same time, multi‑stage pressure drop effectively suppresses cavitation.

4. High Allowable Differential Pressure: The balanced plug design allows a much higher differential pressure than single‑seat valves of the same size, making it suitable for high‑pressure‑drop services.

5. Interchangeable Seat: The sleeve and seat are independent components; sleeves with different flow characteristics or seats of different materials can be easily replaced for maintenance or application changes.

6. High Shut‑Off Performance: Soft sealing achieves ANSI Class VI (bubble‑tight), and metal sealing achieves Class IV.

7. No Compressed Air Required: Only electrical power and a control signal are needed – ideal for locations without an air supply.

8. Remote / Local Control: Supports remote automatic control and on‑site manual operation (via handwheel).

9. Valve Position Feedback: Can output a 4–20 mA or 0–10 V position signal for monitoring by a host system.

Working Conditions

1. Applicable Media: Water, steam, gas, oil, chemical media, corrosive liquids, etc.

2. Temperature Range: –29°C to +200°C (standard PTFE packing); –29°C to +400°C (graphite packing); –196°C to +450°C (bellows seal + extension bonnet).

3. Pressure Rating: PN16, PN25, PN40, PN63, PN100, PN160 (Class 150, 300, 600, 900).

4. Nominal Diameter: DN15 – DN400 (1/2″ – 16″).

5. Power Supply: AC 220V or AC 380V (standard); DC 24V optional.

6. Control Signal: 4–20 mA, 0–10 V DC, etc.

7. Feedback Signal: 4–20 mA (optional).

8. Typical Applications:

   1. High‑pressure steam pressure reduction and temperature control

   2. Compressor discharge flow/pressure regulation (noise reduction required)

   3. High‑pressure liquid pipelines (anti‑cavitation)

   4. Boiler feedwater control

   5. High‑differential‑pressure process control in petrochemical plants

   6. Desuperheating stations in power plants

   7. Gas regulation in air separation units

Summary

The Electric Sleeve Control Valve, with its advantages of sleeve (cage) balanced plug design, pressure balance, noise reduction, anti‑cavitation, high allowable differential pressure, and no need for compressed air, is an ideal control valve for high‑differential‑pressure, large‑flow, and low‑noise applications. Compared with single‑seat control valves, the sleeve valve offers a much higher allowable differential pressure with a smaller actuator. Compared with pneumatic control valves, the electric sleeve valve eliminates the need for an air supply system, simplifying installation and maintenance. The multi‑port sleeve effectively reduces fluid noise and suppresses cavitation, making it particularly suitable for steam, high‑pressure gas, and high‑pressure liquid services. The valve features flanged connections and can be equipped with various options to meet different automation requirements. For pipeline systems that require precise regulation under high differential pressure, noise control, or cavitation prevention, the Electric Sleeve Control Valve is a reliable, efficient, and economical solution.