Locator
The components of the pneumatic actuator must be matched with the actuator when in use. It can improve the position accuracy of the valve and reduce the influence of the frictional force of the valve stem and the unbalanced force of the medium, so as to ensure the correct positioning of the valve according to the signal provided by the regulator. Under what circumstances need to configure a positioner for the pneumatic flow control valve:
1. When the medium pressure is high and the pressure difference is large;
2. When the caliber of the regulating valve is too large (DN>100);
3. High temperature or low temperature regulating valve;
4. When it is necessary to increase the operating speed of the regulating valve;
5. When split control is required;
6. When a standard signal is required to operate a non-standard spring actuator (the spring range is outside of 20～100KPa);
7. When realizing the reverse action of the valve (the air-to-close type and the air-to-open type are interchangeable);
8. When the flow characteristics of the regulating valve need to be changed (the positioner cam can be changed);
9. When there is no spring actuator or piston actuator, it is necessary to achieve proportional action;
10. When using electrical signals to operate pneumatic actuators, power must be distributed to the pneumatic valve positioner.
The electromagnetic valve
When the system needs to achieve program control or two-position control, it needs to be equipped with a solenoid valve. When selecting a solenoid valve, in addition to considering AC and DC power supply, voltage and frequency, attention must be paid to the relationship between the solenoid valve and the regulating valve. Normally open or normally closed can be used.
If you need to increase the capacity of the solenoid valve to shorten the action time, you can use two solenoid valves in parallel or use the solenoid valve as a pilot valve in combination with a large-capacity pneumatic relay.
Pneumatic relay
Pneumatic relay is a kind of power amplifier, which can send the air pressure signal to a far place, eliminating the lag caused by the lengthening of the 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. Another function is to amplify or reduce the signal.
converter
The converter is divided into a gas-electric converter and an electric-gas converter, and its function is to realize the mutual conversion of a certain relationship between gas and electric signals. When using electrical signals to manipulate pneumatic actuators, the converter can convert different electrical signals into different pneumatic signals.
Air filter pressure reducing valve
The air filter pressure reducing valve is an accessory in industrial automation instruments. 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 for various pneumatic instruments and solenoid valves. , Air supply and voltage stabilizing device for cylinders, spraying equipment and small pneumatic tools.
Self-locking valve (position valve)
The self-locking valve is a device that maintains the valve position. When the air source fails, the device can cut off the air source signal to keep the pressure signal of the membrane chamber or cylinder at the state immediately before the failure, so the valve position is also maintained at the position before the failure.
Valve position transmitter
When the regulating valve is far away from the control room, in order to accurately understand the valve switch position without on-site, it is necessary to equip a valve position transmitter. The signal can be a continuous signal reflecting any opening of the valve, or it can be regarded as the reverse action of the valve positioner.
Travel switch (responder)
The travel switch reflects the two extreme positions of the valve switch and sends out an indication signal at the same time. Based on this signal, the control room can turn off the switch state of the valve in order to take corresponding measures.
Post time: Oct-08-2021