An electro-pneumatic valve positioner is the core control accessory of a pneumatic control valve: it receives a standard 4-20 mA DC current signal and outputs a proportional air pressure to drive the actuator, compensating for packing friction and process differential pressure so the valve travel tracks the command linearly. The HEP design uses a mechanical feedback linkage rather than digital electronics, which gives it strong immunity to vibration and dust and makes it a robust choice for conventional industrial modulating service. Direct- and reverse-acting modes can be switched on site, and the standardized pneumatic module fits both single- and double-acting diaphragm and cylinder actuators. With a control accuracy of +/-0.5% FS, IP65 enclosure and a 0.14-0.7 MPa supply range, it is a cost-effective, easy-to-maintain positioner for standard plant loops.
Where a smart positioner is chosen for diagnostics, the HEP is bought for reliable, low-cost modulation on everyday loops. Because we machine the positioner's pneumatic valve block and feedback linkage in-house instead of buying finished sub-assemblies, we can match the output characteristics to our own diaphragm, cylinder and scotch-yoke actuators and tune the friction compensation on the bench. This universal matching means a buyer ordering a complete control valve receives the positioner already mounted and commissioned to that actuator, rather than a generic unit that needs field re-setting.
Specifications
|
Parameter |
Specification |
|
Input control signal |
4-20 mA DC |
|
Supply air pressure |
0.14-0.7 MPa |
|
Output pressure |
0-0.5 MPa linear output |
|
Control accuracy |
+/-0.5% FS |
|
Action mode |
Direct / reverse acting, field switchable |
|
Compatible actuators |
Diaphragm and cylinder pneumatic actuators |
|
Protection rating |
IP65 |
|
Ambient environment |
-20 C to +70 C, dust- and vibration-resistant |
Applications
1. Diaphragm pneumatic control valves in chemical and HVAC loops
The mechanical feedback compensates stem packing friction, so the valve modulates linearly despite sticky packing without needing a digital controller.
2. Cylinder-type high-pressure control valves
The 0.14-0.7 MPa supply range and linear 0-0.5 MPa output give stable thrust control on high-differential-pressure service where a diaphragm actuator alone cannot hold position.
3. Eccentric rotary and V-ball valves on steam and micro-pressure nitrogen-seal service
Direct/reverse on-site switching and dust/vibration resistance keep commissioning simple in standard plant environments where explosion-proof electronics are not required.
Customization
- Direct / reverse acting configuration per the loop requirement
- Mounting brackets for diaphragm, cylinder and scotch-yoke actuators
- Matching with filter regulator, solenoid valve and limit-switch kits
- Low-temperature / corrosion-resistant variants on request
- OEM/ODM supply and labeling
- Sample testing under the customer's working conditions
Packaging & Transportation
Standard export packing of the positioner with its mounting fittings. Before shipment we supply the signal-calibration test video, packing photos, packing list and export customs documents. The cargo is tracked throughout; on arrival damage is handled by remote video guidance or immediate replacement-part shipment.
FAQ
Q. Is the HEP positioner compatible with our existing diaphragm or cylinder actuators?
A. Yes. The HEP is a universal electro-pneumatic positioner that fits single- and double-acting diaphragm and cylinder actuators, with direct/reverse acting switchable on site.
Q. Can you provide samples for testing?
A. Yes. We charge only the material cost for samples and no high sample-service fee; we do not provide free samples.
Q. How do you guarantee quality?
A. We run an ISO9001 quality system and each positioner is tested for signal linearity and air tightness before delivery, with after-sales support from our technically trained team.
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