Your Leading Control Valve Manufacturer in China
JiangHeng brand control valves in the industrial field, shipbuilding field, construction field and other industries with 1% (with positioner) industry-top control accuracy, precision control of the smooth and effective use of various media in its field, for customers of the medium loss has also brought a significant reduction.
JiangHeng control valve, through intelligent electric drive collocation, makes it have a self-learning flow characteristic, which can control the accuracy at ±0.5% (with positioner).
For extreme applications, it is also possible to customize control valves containing rare materials, sizes, sealing surface materials, drive methods, pressure sizes, colors, etc. according to your requirements in JiangHeng.
Whether you choose a control valve for industrial or general use. JiangHeng is your best supplier. We offer competitive prices while also guaranteeing quality.
FAQ—Industrial Control Valve
The control valve accurately controls process parameters such as flow, pressure, and temperature by adjusting the opening . The core difference is:
- Automation integration : receiving 4-20mA, pneumatic signals, etc., and linking with DCS/PLC systems;
- Dynamic performance : high-precision positioner, fast response design (such as electro-hydraulic actuator);
- Flow characteristics : linear, equal percentage, quick opening and other curves to match process requirements.
Classification by driving mode and structure:
- Actuators : pneumatic (most commonly used), electric, electro-hydraulic (high pressure difference);
- Valve body type : single-seat valve (high sealing), double-seat valve (large flow), cage valve (noise reduction), V-type ball valve (slurry control);
- Selection key : CV value calculation, pressure difference (ΔP), medium characteristics (corrosiveness/viscosity), leakage level (ANSI Class IV/V).
- Q = flow rate (GPM);
- SG = medium specific gravity;
- ΔP = differential pressure (psi).
Key installation specifications:
- Flow direction mark : ensure that the arrow on the valve body is consistent with the flow direction of the medium (especially single-seat valve);
- Straight pipe section : 10D before the valve and 5D after the valve (to prevent turbulence interference);
- Bypass setting : Install a manual stop valve for easy maintenance;
- Positioner Calibration: Perform zero/span calibration after installation (HART protocol or local adjustment).
Possible reasons:
- Improper PID parameters : adjust gain (Gain), integral time (Ti);
- Mechanical friction : Insufficient valve stem lubrication or packing too tight, use low friction graphite packing;
- Positioner failure: Check the air source pressure (≥1.4Bar) or upgrade the smart positioner (such as Fisher DVC6200).
According to process requirements:
- Linear characteristics : pressure/liquid level control (ΔP stable);
- Equal percentage : temperature/flow control (large ΔP change);
- Quick opening feature: when only quick opening and closing is required (such as safety cut-off).
According to ANSI FCI 70-2 standard:
- Class II : 0.5%×CV (general regulation);
- Class IV : 0.01%×CV (critical sealing, such as high-temperature steam);
- Class VI: Bubble seal (soft seal, for hazardous media).
Advantages of smart positioners (such as Siemens SIPART PS2, Emerson DVC):
- Self-diagnosis function : real-time feedback of valve health status (friction, stroke deviation);
- HART/FF communication : remote parameter configuration and calibration;
- Adaptive control: Automatically compensates for pressure fluctuations and improves response speed.
Key Materials:
- Valve body/valve core : Inconel 718 (temperature resistance ≤700℃), Stellite 6 alloy coating;
- Valve seat : metal hard seal (surfacing Stellite alloy);
- Actuator: High temperature resistant diaphragm (fluororubber FKM) or electro-hydraulic drive.
Maintenance strategy:
- Monthly inspection : draining of air source filter and loosening of positioner feedback rod;
- Annual overhaul : valve seat sealing test, actuator air tightness test;
- Predictive maintenance : Analysis of travel time/pressure curves via valve diagnostic software such as Emerson AMS.