Talking about the principle of pneumatic control valve

- May 12, 2018-

Pneumatic control valve, also known as control valve, is a device in the process control system that uses power to change the flow. Pneumatic control valve is actuated by the actuator and the body part of the actuator, and the valve body part regulates the flow. Pneumatic control valve is the type of actuator tension. The actuator is a meter that directly changes the manipulated variable and is a terminal component. In addition to regulating valves, actuators include pneumatic motors, pneumatic manipulators, solenoid valves, and electric variable speed pumps.

The actuator is a device that converts the control flag signal into a corresponding action to control the position of the closure member in the valve or the status of other adjustment mechanisms. Flag lights or driving forces can be pneumatic, electric, hydraulic or any combination of these three. The valve body part adjusts the regulating part of the pneumatic regulating valve. The tension consists of the valve housing, the valve stem, the valve core, the valve seat, the gland and the seal. They are in direct contact with the medium. Under the impetus of the actuator, the flow area between the valve plug and the valve seat is changed so as to adjust the flow.

Pneumatic regulating valve adopts multi-spring pneumatic membrane actuator. The single-seat regulating valve body adopts equal-section S-shaped flow channel design. The valve core adopts top guiding structure and has small volume, light weight and flow.

The benefits of large capacity, small leakage, etc.; sleeve, two-seat control valve with pressure balance structure, with the advantages of allowing large pressure difference, smooth operation, low noise and other benefits.

According to the allowable pressure difference, media characteristics and process piping requirements, single seat, double seat, sleeve, angle, diaphragm and three-way regulating valve can be selected;

According to the process requirements, the flow characteristics can be selected as straight line, equal percentage, quick opening;

According to the pressure situation, the nominal pressure can be PN1.6MPa, PN4.0MPa, PN6.4Mpa control valve;

According to the requirements of medium anti-corrosion and pressure grade, the control valve made of cast iron, cast steel, cast stainless steel, cast alloy steel, and forged steel can be selected;

According to the medium temperature and the special requirements, standard, high-temperature heat-dissipating, low-temperature, jacketed heat-insulating control valves can be used.

According to media leakage and safety considerations, optional hard seals, soft seals, bellows seals and other regulating valves; Our factory hard seal control valve leakage level is higher than IV; soft seal control valve can be done without leakage;

According to the air source and the control equipment, the optional banner light range is 20~100Kpa, 40~200Kpa, 4~20mA.DC, 0~10mA.DC;

According to process control requirements, can be equipped with the following accessories: hand wheel mechanism, valve positioner, air filter pressure reducer, electro-pneumatic converter, valve position transmitter, solenoid valve, position valve and so on.

Installation is more serious for every industrial instrument. What's more, it is a very sensitive pneumatic valve working principle? Then when the installation should be carefully planned to those titles advertising in order to ensure the correct installation? The installation method of the working principle of the pneumatic control valve is emphasized. The tension is because there is no correct installation, and it cannot be guaranteed that it can be used in the subsequent use. Therefore, many faults will occur, thereby affecting the service life of the pneumatic control valve.

With the corresponding straight pipe:

When installing the pneumatic control valve must have a straight pipe, and the length of the straight pipe should be more than ten times the diameter, so as to ensure that when the fluid passes through the pneumatic control valve, the heading that will not affect the flow due to the straight pipe passing through the segment will appear. .

Reducer connection:

Use this method to connect the tension is because the caliber of the regulating valve is different, then when the installation is carried out, it is necessary to elaborate on these titles. After all, the fluid direction arrow on the valve body should be aligned with the direction of fluid flow, so as to ensure that The caption does not appear when using a pneumatic valve.

To set the bypass pipe:

In the installation of pneumatic control valve, in order to be able to simply operate, you should use manual operation, and be prepared to switch, so you can ensure that in the case of one-way machine, check the working principle of the pneumatic valve to build the site costs , If you encounter a heading, it is also convenient for maintenance.

In the daily production process, the maintenance of the pneumatic control valve is limited to the fault handling of the valve, and the periodical adjustment and periodic inspection are seldom carried out. There is no strict requirement for the company's measurement and management procedures. In fact, The failure of the valve stems from the accumulation of a number of non-intrusive factors, which accumulate to a certain degree and cause failures. Therefore, these non-intrusive factors are precluded from occurring in the bud before the failure of the valve, and not only can the service life of the valve be extended, but also It can avoid the severe effect of the valve due to the failure of the production.