Classification of regulating function of instrument valves

Classification of regulating function of instrument valves
According to the energy used, instrument valves can be divided into pneumatic instrument valve, hydraulic instrument valve and electric instrument valve; According to the principle and structure, it can be divided into self operated instrument valve, base type regulating instrument valve, simple regulating instrument valve, unit combined instrument valve and assembled integrated control device.
According to the regulation function, instrument valve is divided into two position instrument valve, proportional instrument valve, PI instrument valve (proportional integral instrument valve), PID instrument valve (proportional integral differential regulator), feed-forward instrument valve, etc.
1. Self operated instrument valve
The regulating valve is driven by the energy of the regulated medium itself or after simple conversion to realize automatic regulation. Floating ball liquid level regulator (such as toilet) is to use the buoyancy of floating ball on the liquid surface to make the regulating valve act. This kind of regulator does not need external energy and is a kind of local regulating device. It is simple in structure and easy to maintain. It is suitable for single parameter regulation system with low control accuracy. It is very similar to pneumatic actuator in principle and structure, and is often classified as actuator.
2. Base type instrument valve
The utility model relates to an indicating and recording instrument with an additional adjusting mechanism. It receives the signal from the detecting element, drives the regulating mechanism to send out the control signal by the action of the indicating and recording mechanism, and sends it to the actuator to realize the automatic adjustment. Moving coil indicating and regulating instruments, electric and pneumatic recording instruments with electric or pneumatic regulators all belong to this type. They are widely used to control single production equipment. Simple instrument valve is a kind of adjustment instrument which can directly accept the signal of detection elements, without indication mechanism, with strong specificity and simple structure. It can also receive signals from the transmitter. Non indicating regulator and temperature alarm are simple regulating instruments, which are widely used in small and medium enterprises.
3. Unit combination instrument
A set of regulating instruments composed of several standard units with independent functions. It fully meets the requirements of large units and process control, and can realize complex control of multiple loops (see electric unit combination instrument and pneumatic unit combination instrument).
4. Assembled integrated control device
The assembled instrument is a special control device which is composed of various independent functional components according to the requirements of a large unit or process control. It can be assembled according to the needs of users, so it has great flexibility.