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The first type of automatic valve: a valve that operates by itself depending on the capacity of the medium (liquid, gas).

Such as check valve, safety valve, regulating valve, drain valve, pressure reducing valve, etc.

The second type of drive valve: the valve operated by manual, electric, hydraulic and pneumatic means.

Such as gate valve, globe valve, throttle valve, butterfly valve, ball valve, plug valve, etc.

2、 According to the structural characteristics, it can be divided according to the moving direction of the closing member relative to the valve seat:

1. Truncated gate shape: the closure moves along the center of the valve seat;

2. Gate shape: the closing member moves along the center of the vertical valve seat;

3. Cock and ball: the closing part is a plunger or ball, which rotates around its center line;

4. Swing type: the closing part rotates around the shaft outside the valve seat;

5. Disc shape: the disc of the closing member rotates around the shaft in the valve seat;

6. Slide valve shape: the closing member slides in the direction perpendicular to the channel.

3、 According to the use, the valve can be divided into:

1. Disconnection: used to connect or cut off pipeline medium, such as stop valve, gate valve, ball valve, butterfly valve, etc.

2. Check valve: it is used to prevent medium backflow, such as check valve.

3. Regulating: used to regulate the pressure and flow of medium, such as regulating valve and pressure reducing valve.

4. Distribution: used to change the flow direction of medium and distribute medium, such as three-way cock, distribution valve, slide valve, etc.

5. Safety valve: when the medium pressure exceeds the specified value, it is used to discharge excess medium to ensure the safety of pipeline system and equipment, such as safety valve and emergency valve.

6. Other special uses: such as drain valve, vent valve, blow down valve, etc.

4、 According to the driving mode, it can be divided into:

1. Manual: with the help of handwheel, handle, lever or sprocket, there is manual drive, and worm gear, gear and other reduction devices are available when driving large torque.

2. Electric: driven by motor or other electrical devices.

3. Hydraulic: driven by (water, oil).

4. Pneumatic: driven by compressed air.

5、 According to the pressure, according to the nominal pressure of the valve, it can be divided into:

1. Vacuum valve: the valve with absolute pressure less than 0.1MPa, i.e. 760mm Hg, is usually expressed in mm Hg or mm water.

2. Low pressure valve: valve with nominal pressure PN ≤ 1.6Mpa (including steel valve with PN ≤ 1.6Mpa)

3. Medium pressure valve: valve with nominal pressure of pn2.5-6.4mpa.

4. High pressure valve: valve with nominal pressure of pn10.0-80.0mpa.

5. Ultra high pressure valve: valve with nominal pressure PN ≥ 100.0mpa.

6、 According to the medium temperature, it can be divided according to the medium temperature when the valve is working:

1. Ordinary valve: suitable for valves with medium temperature of - 40 ℃ ~ 425 ℃.

2. High temperature valve: suitable for valves with medium temperature of 425 ℃ ~ 600 ℃.

3. Heat resistant valve: suitable for valves with medium temperature above 600 ℃.

4. Low temperature valve: applicable to valves with medium temperature of - 150 ℃ ~ - 40 ℃.

5. Ultra low temperature valve: applicable to valves with medium temperature below - 150 ℃.

7、 According to the nominal diameter, it can be divided into:

1. Small diameter valve: valve with nominal diameter DN < 40mm.

2. Medium diameter valve: valve with nominal diameter of DN50 ~ 300mm.

3. Large diameter valve: valve with nominal diameter of DN350 ~ 1200mm.

4. Extra large diameter valve: valve with nominal diameter DN ≥ 1400mm.

8、 According to the connection mode with pipeline, it can be divided into:

1. Flange connected valve: the valve body is provided with flange, and the pipeline is connected with flange.

2. Threaded connection valve: the valve body is provided with internal thread or external thread, and the valve is connected with the pipeline by thread.

3. Welded connection valve: the valve body is provided with welded junction and is welded to the pipeline.

4. Clamp connected valve: the valve body is provided with a clamp mouth and is connected with the pipeline by clamp.

5. Ferrule connected valve: the valve connected by ferrule and pipeline.