Before each THINKTANK control valve leaves the factory, our engineers will complete the material tests, NDT tests, hydraulic tests, sealing tests, leakage tests, and function tests. However, due to the collision or displacement during transportation, the control valve should be debugged again after being installed on site.
Today we will talk about how to quickly debug the mechanical electro positioner of the pneumatic diaphragm control valve.
Firstly, when the air source is connected, adjust the pressure gauge to the required pressure value of the actuator. For example, 0.2bar air supply of 40-200kpa spring diaphragm actuator, 2.4bar air supply of 80-240kpa spring range. Generally, the air source pressure of the diaphragm actuator cannot exceed 3.5bar, otherwise, the diaphragm will be easy to be damaged.
- This actuator spring range is 80-240kpa, so we first adjust pressure regulator to 2.4bar.
- Open junction box and connect the analog signal positive and negative poles.
- Open positioner cover, adjust it manually to ensure the feedback rod is in the horizontal position when valve is at 50% opening, and then fix the feedback rod clamp block.
- Calibrate the zero position. 0% travel length. This black wheel is the zero adjust knob. Set the input signal to 4 mA to see if the positioner output pressure is zero. If not, adjust the black knob to make the output pressure gauge drop to zero, indicating that the valve is in the initial position (If it is air to open, the valve should be in closed position. If it is air to closed, at 4 mA, the valve should be in the fully open position). We can see that this valve is now in closed position.
- Input 5 mA signal to see if the valve responses. If no feedback, adjust zero adjust knob till the positioner output pressure gauge and valve start action. Back to 4 mA input signal to see if the valve in closed position. In another word to see if positioner pressure gauge is in zero position. If it doesn’t back to zero, keep adjusting the knob till pressure gauge is in zero adjustment. Input 5 mA signal again, valve starts response.
- Adjust the range. 100% full travel position. Input 20 mA, whether the valve is at 100% opening. If the valve travel indicator is too low or too high, it is necessary to readjust the full position. Loosen the locking screw and adjust the travel lever. The + sign indicates an increase in travel. The – sign means to reduce travel length. If the valve does not reach 100% position after 20 mA is given, move the screw to + direction by 1 mm. Then tighten the locking screw. In particular, it is necessary to readjust the zero position after adjusting the 100% full range opening. Now input 4 mA signal and check whether the valve is 0. If not, repeat step 4 until the valve returns to zero. Give 20 mA signal again to see if the valve is in the 100% travel position. If it is not in the full range position, adjust the locking screw position again.
- After adjusting the full range and zero position, input 4 mA, 8 mA, 12 mA, 16 mA and 20 mA in turn to see if the travel indicator needle corresponds to the 0%, 25%, 50%, 75% and 100% positions of the travel plate. So far, the mechanical electrical positioner debugging is completed.
HEP15, HEP16, HEP Valve Positioner Manufacturer
|Type||HEP15: Explosion-proof, HEP16: Intrinsically-safety, HEP17:Water-proof|
|Input signal||4～20mA, 4～12, 12～20mA·DC|
|Output characteristics||Linear, equal percentage, quick-opening|
|Air consumption||4L/min (Air supply: 140kPa)|
|Flow capacity||Max.110L/min (Air supply:140kPa|
|Air connection||Rc1/4″, 1/4NPT, G1/4″|
|Ambient temp.||－40～＋60℃（Explosion Site）,－40～＋80℃（Standard Site）|
|Shell construction||HEP15:Ex. Certification dⅡCT6, as per standard GB3836.1, GB3836.2; Protection class of shell: IP65, as per standard GB4208, HEP16: Ex. Certification iaⅡCT6 Gb, as per standard GB3836.1,GB3836.4; Protection class of shell:IP65, as per standard GB4208|
|Wire connection||M20×1.5,1/2NPT, G1/2″|
|Performance||Accuracy: Within ±1% FSDead band: Within 0.1% FS|
|Speed||4mm/s（HA2D Pneumatic Actuator）|