Instrumentation valve overview

Instrument valve: The use of analog signal regulator, also known as analog instrument valve. It determines the deviation of the simulated form measurement value of the controlled object parameter from the given value, and generates an analog output signal according to a certain regulation rule to push the actuator to eliminate the deviation, so that the controlled parameter is maintained near a given value or changes according to a predetermined rule. In automated meters, meter valves are often used to synthesize the output signals of the meter to achieve control of the production process. The parameters that are adjusted include temperature, pressure, flow, level, composition, and the like.

Instrument valve classification

According to the energy used, the instrument valves are divided into three categories: pneumatic instrument valves, hydraulic instrument valves, and electric instrument valves; according to the principle and structure, they can be divided into self-operated instrument valves, base-type regulation instrument valves, simple regulation instrument valves, and unit instrument clusters. Valves and assembled integrated control devices. The instrument valve is further divided into two instrument valves, proportional instrument valves, PI instrument valves (proportional integral instrument valves), PID instrument valves (proportional-integral differential adjusters), feed-forward instrument valves, and the like.

1 The self-operated instrument valve can be adjusted automatically by adjusting the energy of the medium itself or after a simple conversion. Float-type liquid level regulators (such as toilets) use the buoyancy of the float on the liquid surface to actuate the regulating valve. This regulator does not require external energy and is an on-site adjustment device. It has a simple structure and is easy to maintain. It is suitable for single parameter adjustment systems with low control accuracy. It is very similar in principle and structure to pneumatic actuators and is often referred to as actuators.

2 Base type instrument valve An indicator recording instrument with an additional adjustment mechanism. It accepts the signal sent by the detection element, drives the adjustment mechanism to issue a control signal by the instruction and recording mechanism, and sends it to the actuator to achieve automatic adjustment. Dynamic coil indicating and regulating instruments, electric and pneumatic recording instruments with electric or pneumatic actuators belong to this type, and they are widely used to control single production equipment.

2 simple instrument valve A signal that can directly receive the detection element, without indicating mechanism, special and strong and simple structure of the adjustment instrument. It can also accept transmitter signals. No indicator regulators and temperature alarms are simple regulators and are widely used in small and medium-sized enterprises.

4-unit combination meter A set of adjustment meters consisting of several standard units with independent functions. It can fully meet the requirements of large-scale units and process control, and can achieve complex control of multiple circuits (see electric unit combination meter, pneumatic unit combination meter).

5 Assembled type integrated control device For short assembly type instrument, it is a special control device that 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 user's needs and therefore has great flexibility.