What is pneumatic control valve and its classification method?

Pneumatic control valve is a pneumatic component that controls and adjusts the direction, pressure and flow of compressed air. They can be used to form various pneumatic circuits, so that the pneumatic actuator can work normally according to the design requirements.

1 common pneumatic control valve:

Similar to the hydraulic control valve, the commonly used basic pneumatic control valves are divided into: pneumatic direction control valve, pneumatic pressure control valve and pneumatic flow control valve. In addition, there are pneumatic logic elements, which can realize various logic functions by changing the direction of air flow and switching.

1. 1? Pneumatic directional control valve:

Pneumatic directional control valve is a kind of pneumatic component used to control the direction of compressed air flow and the interruption of air flow.

1. 1. 1? Classification of pneumatic directional control valves

Pneumatic directional valve is similar to the directional valve of hydraulic system, and it is also divided into one-way valve and directional valve, and its classification method is basically the same. However, due to the uniqueness of pneumatic transmission, pneumatic reversing valves can be classified according to valve core structure and control mode.

A. cut off the directional control valve

b.？ Sliding column directional control valve

1. 1.2? General pneumatic directional control valve

a.？ Unidirectional directional control valve

1) check valve

2) or gate shuttle valve

3) Shuttle valve

4) quick exhaust valve

b.？ Reversing control valve

Reversing valve (abbreviated as reversing valve) changes the direction of gas flow by changing the airflow channel, thus changing the movement direction of pneumatic actuator. It includes pneumatic control reversing valve, electromagnetic control reversing valve, mechanical control reversing valve, manpower control reversing valve and time control reversing valve.

(1) Pneumatic control directional valve

According to different control methods, it can be divided into three types: pressurization control, pressure relief control and pressure difference control.

According to the different structure of main valve, pneumatic reversing valve can be divided into two categories: stop valve and slide valve.

(2) Electromagnetic control direction control valve

1)? Single electronic control reversing valve

2)? Double electronically controlled electromagnetic reversing valve

(3) Mechanical control or manpower control direction control valve

(4) Time-controlled reversing valve

Time reversing valve is a reversing valve that controls the reversing time of the valve through the action of gas capacity or gas resistance. Comprise a delay valve and a pulse valve.

1.2? Pneumatic pressure control valve

Pneumatic pressure control valve mainly plays the role of adjusting, reducing or stabilizing the pressure of air source, controlling the action sequence of actuator and ensuring the safety of the system.

1.2. 1? Classification of pneumatic pressure control valves

Pneumatic pressure control valve is divided into pressure reducing valve (pressure regulating valve), sequence valve and safety valve.

1.2.2? Ordinary pneumatic pressure control valve

A. pressure reducing valve

(1) direct-acting safety valve

(2) Pilot-operated pressure reducing valve

(3) setting device

B. Sequence valve

C. safety valve

1.3? Pneumatic flow control valve

Flow control valve is an element to realize flow control by changing the flow area of the valve. The flow control valve includes throttle valve, one-way throttle valve, exhaust throttle valve and flexible throttle valve.

A. throttle valve

B. Flexible throttle valve

C. exhaust throttle valve

D. one-way throttle valve

2 Pneumatic logic control valve

2. 1? Classification of pneumatic logic elements

There are many kinds of pneumatic logic elements, which can be classified according to different characteristics.

A. According to the working pressure

(1) high pressure type? Work stress? 0.2 ~ 0.8 MPa

(2) Low pressure type? Work stress? 0.05 ~ 0.2 MPa

(3) micro-pressure type? Work stress? 0.005 ~ 0.05 MPa

B. According to the structure type

The structure of an element always consists of a switch part and a control part. The switch part moves back and forth under the action of the control air pressure signal to change the air flow path and complete the logic function. According to the composition principle, the structural types of pneumatic logic elements can be divided into three categories:

(1) cut-off type? The on-off of the gas path depends on the opening or closing of the gas port formed by the end face (plane or cone) of the movable part and the gas nozzle.

(2) Sliding column type (slider type)? According to the movement of the sliding column (or slider), the vent can be opened or closed.

(3) diaphragm type? The opening and closing of the gas path depends on the deformation of the elastic diaphragm to open or close the gas port.

C. According to the logical function

According to the nature of logic function, components with binary logic function can be divided into two categories:

(1) single function element? Each element has only one logical function, such as OR, NOT, AND, bistable, etc.

(2) Multifunctional components? Each element has a variety of logical functions, which are obtained through different connection methods. Such as a three-diaphragm multifunctional pneumatic logic element.

2.2? Main logic element

2.2. 1? High voltage cut-off logic element

A. or gate element

B. It is the gate and AND gate element.

C. Non-gate and gate prohibition elements

D. non-element

E. bistable element

2.2.2? High voltage diaphragm logic element

High-pressure diaphragm logic element uses the deformation of diaphragm valve core to realize its logic function. The most basic units are three elements and four elements.

A. Three-door element

B. Four-door element

3 Pneumatic proportional, servo and digital control valve

3. 1? Pneumatic proportional control valve

A. pneumatic proportional pressure valve

B. Electronically controlled proportional pressure valve