Single-Seat Control Valve

I. Product Overview
The single-seat control valve is the most commonly used linear-motion control valve in industrial automation systems. It consists of a valve body, plug, seat, stem, packing assembly, and a pneumatic or electric actuator. By receiving a 4–20 mA analog signal, it precisely adjusts the plug opening to achieve continuous regulation and stable control of pipeline media flow, pressure, temperature, and liquid levels.
The valve body features a streamlined S-shaped flow path, offering low flow resistance, high control precision, and excellent sealing performance. It is characterized by low leakage, responsive operation, and stable performance. Suitable for the vast majority of clean and mildly corrosive industrial fluid applications, it serves as a core control component in automation systems for the chemical, power, HVAC, and water treatment industries.
II. Structural Features

1. Single-seat sealing structure: Features a single-plug, single-seat design that ensures superior sealing performance and extremely low leakage (meeting National Standard Class V leakage requirements), making it ideal for applications demanding high sealing integrity.
2. Top-guided structure: Utilizes top guiding for small sizes and retaining-ring guiding for large sizes; the plug operates smoothly without vibration or jamming and offers strong vibration resistance.

• Streamlined flow path: Ensures unobstructed flow, low pressure drop, and a high flow coefficient; offers a wide rangeability and precise control linearity.
• Modular configuration: Compatible with pneumatic diaphragm or smart electric actuators; supports the addition of valve positioners, solenoid valves, handwheel mechanisms, and explosion-proof components.
• Easy disassembly and maintenance: Features a top-entry design, allowing for internal inspection and the replacement of the plug and packing without removing the valve from the pipeline.
• Reliable packing seal: Uses graphite or PTFE packing to ensure high-temperature resistance and durable sealing, preventing external leakage during long-term operation. III. Common Material Configurations
  Valve Body: WCB Carbon Steel, 304 (CF8), 316L (CF8M), 2205, 2507, 904L
  Valve Plug/Seat: 304, 316L, Stellite hard-facing (wear-resistant and erosion-resistant)
  Packing: PTFE, Flexible Graphite
  Gasket: Stainless steel spiral wound gasket, PTFE gasket
  IV. Technical Parameters

1. Nominal Diameter: DN20–DN200
2. Pressure Rating: PN16, PN25, PN40, PN64; CL150–CL300
3. Flow Characteristic: Linear, Equal Percentage, Quick-opening
4. Control Signal: 4–20mA DC / 0–10V DC
5. Leakage Class: Class IV, Class V (High-precision sealing)
6. Operating Temperature: -20°C to +420°C (selected based on material)
7. Connection Type: Flanged, Welded, Threaded
8. Actuation: Pneumatic diaphragm, Electric intelligent
   V. Applicable Working Conditions and Scope of Use
   Single-seat control valves are suitable for regulating clean fluids with low impurity levels and low-to-medium pressure differentials; they have a wide range of applications:
9. Petrochemical and fine chemical industries: Acid/alkali medium regulation
10. Power plants and district heating: Steam and hot water temperature/pressure regulation
11. Water treatment: Pure water and sewage process flow regulation
12. HVAC and energy-saving equipment: Fluid automatic control systems
13. Food, pharmaceutical, and light industries: Clean pipeline regulation
14. Gas systems: Pressure and flow stabilization for natural gas, air, nitrogen, etc.
    Not suitable for: Media containing large amounts of particles, or causing high erosion or severe abrasion (use of sleeve-type or hard-sealed control valves is recommended instead).
    VI. Applicable Standards
15. Design Standard: GB/T 4213, IEC 534, ASME B16.34
16. Connection standards: GB/T 9113, ASME B16.5
17. Pressure testing standards: GB/T 13927, API 598
18. Leakage standard: IEC 60534-4
    VII. Installation and Operating Instructions
19. Valves should preferably be installed upright with the actuator facing upwards; inverted, horizontal, or excessively tilted installations are prohibited.

• Clean debris from the pipeline before installation to prevent welding slag from scratching the valve plug or seat, which could cause internal leakage.

1. During commissioning, input a standard 4-20mA signal and verify smooth full-stroke operation without sticking or abnormal noise.

Select explosion-proof actuators for hazardous areas; opening the cover while energized is strictly prohibited, and the equipment must comply with on-site explosion-proof rating requirements.
VIII. Product Advantages
Featuring high control precision, excellent sealing, stable operation, low failure rates, easy maintenance, and high cost-effectiveness, this is a standard control valve offering exceptional versatility and widespread application in industrial fluid control scenarios.

Periodically inspect the packing seal and stem movement; perform full-stroke cycling if the valve has been idle for an extended period.