The electric valve positioner is the main accessory of the control valve. It takes the valve stem displacement signal as the input feedback measurement signal, and uses the controller output signal as the setting signal to perform the comparison. When the two are deviated, the actuator is changed to the actuator. The output signal causes the actuator to act, establishing a one-to-one correspondence between the displacement of the valve stem and the output signal of the controller. Next Xiaobian introduced the role of the electric valve positioner and the characteristics of the electric valve positioner.
Electric valve positioner function
1. The electric valve positioner is an adjustment system that requires high adjustment quality. It needs to increase the positioning accuracy of the regulating valve and increase the reliability.
2. Installation is where the differential pressure across the valve is greater than 1 MPa. By increasing the air pressure to increase the output force of the starter to overcome the force generated by the fluid on the spool to reduce the error in the stroke.
3. To avoid external leakage, when the flowing fluid contains high temperature, high pressure, low temperature, toxic, flammable, explosive and other states, the filler is usually squeezed very tightly, and the friction between the valve stem and the filler is used. Increase, and then use the positioner to overcome the time lag.
4. When the fluid is a viscous fluid or the fluid contains a solid suspension, the use of a positioner can reduce the resistance of the fluid to the movement of the valve stem.
5, the positioner also has to overcome the transmission delay of the control signal and improve the reaction speed of the valve.
6, improve the flow characteristics of the regulating valve.
7. Two positioners can be used when a single regulator controls two actuators, one for low and the other for height. Accept the low input signal and the high input signal respectively to achieve the split-range adjustment state.
Electric valve positioner features
1. Wide application scope: The amplifier of the positioner is applicable to both single-acting actuators and double-acting actuators.
2. The pneumatic power is large, the movement speed is fast, and the power balance adopts multiple circuits, which is not easy to oscillate and the performance of the movement is stable.
3, the locator has a positive and negative role of action, can be easily and easily replace the installation correction.
4. The constant flow orifice of the general positioner will often block and cause the phenomenon that the positioner does not work properly. However, the constant orifice mechanism designed and manufactured by the positioner can operate with the through pin to facilitate the solution of the through hole and maintain the work. The airway is unobstructed.
5, has a good composite explosion-proof function: As the coil components and junction boxes using a reliable explosion-proof structure, the design of the various components into components, so the product has a good composite explosion-proof function of this product, it also has intrinsic safety "i "(ExdIICT6), flameproof "d" (ExdIIBT6).
6. The positioner's enclosure protection class is IP65.
7, compact structure, precise and reliable. This product parts precision die casting, exquisite appearance and internal structure technology. The optimized design of each organization, the overall structure is compact, the use of stainless steel fasteners and advanced spray process, production and manufacturing permanent, etc., has a good anti-corrosion properties.
8, simple adjustment, easy installation: The positioner does not need to open the shell can also achieve zero adjustment, easy adjustment of the stroke range, a wide range of width. The locator case (cover) is fastened with two stainless steel screws. The installation is reliable and convenient. The case (cover) screws are free from loosening and seizure. In the bottom surface of the positioner, screw holes for installation and mounting plates with transitional couplings are provided according to requirements, which can be applied to the convenient installation of various pneumatic actuators.
The role of electric valve positioner
1. It is used to adjust the important quality of the important adjustment system to improve the positioning accuracy and reliability of the regulating valve.
2. Used for occasions where the pressure difference between the two ends of the valve is large (â–³p>1MPa). The output force of the actuator is increased by increasing the pressure of the air source to overcome the unbalanced force generated by the liquid on the spool and reduce the stroke error.
3. When the medium to be adjusted is high temperature, high pressure, low temperature, toxic, flammable and explosive, in order to prevent external leakage, the packing is often pressed tightly, so the friction between the valve stem and the packing is large, and at this time Locator can overcome the time lag.
4. When the medium to be adjusted is a viscous fluid or contains a solid suspension, the positioner can overcome the resistance of the medium to the movement of the valve stem.
5, for large diameter (Dg> 100mm) control valve to increase the actuator's output thrust.
6. When the distance between the actuator and the actuator is over 60m, the positioner can overcome the transmission delay of the control signal and improve the reaction speed of the valve.
7, used to improve the flow characteristics of the regulating valve.
8. When one regulator controls two actuators to perform split-range control, two positioners can be used to respectively accept low input signals and high input signals, and then one actuator performs a low movement and another elevation moves constitutes a division process. adjust.
Editor's summary: The role of the electric valve positioner and the characteristics of the electric valve positioner is introduced here, and I hope to be helpful to everyone. If you want to know more related information, you can pay attention to this website information.
Electric and electric valve positioner function
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