Valve positioner is the main accessory of pneumatic actuator. It is used together with pneumatic actuator to improve the position accuracy of the valve, overcome the influence of friction force of the valve stem and unbalanced force of the medium, and thus ensure the correct positioning of the valve according to the signal sent by the regulator.
A locator is required in the following cases:
1, when the medium pressure is high and the pressure difference is large;
2. When the diameter of the regulating valve is large (DN >；; 100);
3, high temperature or low temperature regulating valve;
4. When it is necessary to improve the action speed of the regulating valve;
5. When operating the actuator of non-standard spring with standard signal (the spring range exceeds 20 ~100 kPa);
6. When used for distance control;
7. When the valve is reversed (gas-closed and gas-open switching);
8. When it is necessary to change the flow characteristics of the valve (the positioner cam can be changed);
9, no spring execution
Mechanical device or piston actuator to realize proportional action;
10. When pneumatic actuators is operated by electrical signals, the power distribution-air valve positioner must be distributed.
solenoid valve
When the system needs to realize program control or two-position control, it needs to be equipped with solenoid valve. When selecting solenoid valve, besides AC and DC power supply, voltage and frequency, we should also pay attention to the relationship between solenoid valve and regulating valve, which can be equipped with "normally open" or "normally closed".
If it is necessary to increase the capacity of solenoid valves to shorten the action time, two solenoid valves can be used in parallel, or the solenoid valves can be used as pilot valves in combination with large-capacity pneumatic relays.
The regulating valve produced by our factory is usually used in conjunction with the solenoid valve produced by Dandong Solenoid Valve Factory. Dandong Solenoid Valve Factory imported advanced solenoid valve technology from HERION Company in Germany, and realized localization. Among them, direct-acting two-position three-way single electric control solenoid valve (including explosion-proof); A 10 1ED-SB024000 series (specifications: 3, 5, 8, 10, 12, 15, 20, 25, 40, 50 mm); Two-position four-way (five-way) single electric control solenoid valve A 102ED-SF025000 series (specifications: 5,8, 12,15,20,25mm). Advantages of direct-acting type: 1 The working medium can work from 0MPa; 2. It can be installed and used at will; 3. The working medium is suitable for water, gas and oil; 4. What's the action? Low power, long service life and high action frequency; 6. The explosion-proof head adopts the combination of additional installation type and flame-proof type, which is convenient for users to wire.
Pilot solenoid valve P4 1 1EI-WFM80200 series (specification: 6,12mm); Two-position five-way single electric control double electric control solenoid valve P4 13EI-WFM2630 series (specification: 6, 12mm).
Please refer to the product samples of Dandong Solenoid Valve Factory for technical parameters during selection.
Pneumatic relay
Pneumatic relay is a kind of power amplifier, which can send the air pressure signal to a long distance and eliminate the lag caused by the long signal pipeline. It is mainly used between the field transmitter and the regulating instrument in the central control room, or between the regulator and the field regulating valve, and has another function of amplifying or narrowing the signal.
converter
Converter is divided into gas-electric converter and electric converter, and its function is to realize the mutual conversion between gas-electric signals. It is mainly used to convert 0 ~ 100 mA or 4 ~ 20 mA electric signal or 0 ~ 100 kPa electric signal into 0 ~ 100 mA or 4 ~ 20 mA electric signal when operating pneumatic actuator with electric signal.
Air filter pressure reducing valve
The pressure reducing valve of air filter is an accessory in industrial automation instrument. Its main function is to filter and purify the compressed air from the air compressor and stabilize the pressure at the required value. It can be used as a gas supply and pressure stabilizing device for various pneumatic instruments, electromagnetic valves, cylinders, spraying equipment and small pneumatic tools.
Self-locking valve (check valve)
Self-locking valve is a device to keep the position of the valve. Pneumatic control valve When the air source fails, the device can cut off the air source signal, so that the pressure signal of the diaphragm chamber or cylinder can be kept in the state of the moment before the failure, so that the valve position can also be maintained in the position before the failure, which plays the role of maintaining the position.
Valve position transmitter
When the regulating valve is far away from the control room, in order to know the on-off position of the valve accurately without going to the scene, a valve position transmitter is needed, that is, the displacement of the valve opening is converted into an electrical signal according to a certain law and sent to the control room. This signal can be a continuous signal reflecting any opening of the valve, or it can be considered as the reverse action of the valve positioner.
Travel switch (transceiver)
The travel switch reflects the two limit positions of the valve switch, and at the same time sends out an indication signal. According to this signal, the control room can close the on-off state of the valve so as to take corresponding measures.
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