The role of pneumatic valve positioner Pneumatic valve is widely used in the electric power technology industry

The role of pneumatic valve positioner Pneumatic valve is widely used in the electric power technology industry

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Valve locator (also known as: Pneumatic valve locator) is the main control valve accessories, usually with Pneumatic Pneumatic control valve, it accepts the regulator output signal, and then to its output signal to control the Pneumatic control valve, when the control valve, the valve stem of the displacement feedback through mechanical device to valve positioner, valve position condition through the electrical signal to the upper system.
Valve positioner structure:
Valve positioner according to its structure form and working principle can be divided into pneumatic valve positioner, electric-gas valve positioner and intelligent valve positioner.
Valve positioner can increase the output power of the regulating valve, reduce the transmission lag of the regulating signal, accelerate the movement speed of the valve stem, can improve the linearity of the valve, overcome the friction of the valve stem and eliminate the influence of the unbalanced force, so as to ensure the correct positioning of the regulating valve.
Valve positioner ADAPTS variety
Commonly used actuators are divided into pneumatic actuators, electric actuators, straight stroke, Angle stroke. Used to open and close all kinds of valves and air plates automatically and manually.
Working principle of valve positioner
The valve positioner is the main accessory of the control valve. It takes the valve stem displacement signal as the input feedback measurement signal, takes the controller output signal as the setting signal, compares, when the two have the deviation, changes its output signal to the actuator, makes the actuator action, establishes the valve stem displacement times and the controller output signal between the one-to-one correspondence. Therefore, the valve positioner consists of a feedback control system with the stem displacement as the measurement signal and the controller output as the setting signal. The control variable of the control system is the output signal of the valve positioner to the actuator.
Classification of valve positioners
Valve positioner is divided into pneumatic valve positioner and electrical valve positioner according to the input signal. The input signal of the pneumatic valve positioner is the standard gas signal, for example, 20~100kPa gas signal, its output signal is also the standard gas signal. The input signal of the electrical valve positioner is the standard current or voltage signal, for example, 4~20mA current signal or 1~5V voltage signal, etc., the electrical signal is converted into electromagnetic force inside the electrical valve positioner, and then the output gas signal to the toggle control valve.
According to the direction of action can be divided into one-way valve positioner and two-way valve positioner. The one-way valve positioner is used in the piston actuator, the valve positioner only works in one direction, the two-way valve positioner works on both sides of the cylinder of the piston actuator, in two directions.
According to the valve positioner output and input signal gain symbol is divided into positive valve positioner and reaction valve positioner. As the input signal to the positive-acting valve positioner increases, the output signal also increases, so the gain is positive. Reaction valve positioner input signal increases, the output signal decreases, therefore, the gain is negative.
According to the valve positioner input signal is analog signal or digital signal, can be divided into ordinary valve positioner and field bus electrical valve positioner. The input signal of the common valve locator is the analog pressure or current, voltage signal, the input signal of the fieldbus electrical valve locator is the digital signal of the fieldbus.
According to whether the valve positioner has CPU, it can be divided into ordinary electrical valve positioner and intelligent electrical valve positioner. Common electrical valve positioners do not have CPU, therefore, do not have intelligence, can not handle the relevant intelligent operations. Intelligent valve positioner with CPU, can handle the relevant intelligent operations, for example, can carry forward channel nonlinear compensation, etc., fieldbus electrical valve positioner can also take P>
Pneumatic valves are widely used in the electric power technology industry
Follow the rapidness of electric power electronic technology and automatic control valve industry, and the development of electric valve actuators also conducted step by step, every second in intelligent s intelligent products is also gradually appear, at that time all industrial control equipment of the present also brings to the shopping mall will surely help, also received a lot of friends, pneumatic valve The development trend of pneumatic valve actuator has gradually improved, and the low-cost single chip microcomputer and new notification microprocessor will replace the imitation of electronic gas parts to become the main control unit of electric valve actuator, and then complete the complete digital control system.
Follow the rapidness of electric power electronic technology and automatic control valve industry, and the development of electric valve actuators also conducted step by step, every second in intelligent s intelligent products is also gradually appear, at that time all industrial control equipment of the present also brings to the shopping mall will surely help, also received a lot of friends, pneumatic valve The development trend of pneumatic valve actuator has gradually improved, and the low-cost single chip microcomputer and new notification microprocessor will replace the imitation of electronic gas parts to become the main control unit of electric valve actuator, and then complete the complete digital control system.
Tradition on the equipment and features from the operation of modern intelligent product lacking on the expanding of ease and integral ease at run time, in fact, the vast majority of valve actuators will attack obvious change, of course scheduling and model parameter identification from moderate control will be * * to improve the control performance of electric valve actuators. Relative to pneumatic and hydraulic valves, simple wiring and powerful function and continue to expand the scale of use. Because the pneumatic valve in the pipe network is usually opened and closed infrequently, the packing does not aging to maintain the sealing effect for a long time.


Post time: Sep-27-2022

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