08

2020

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07

General classification of valves

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Beginners to valves always mistake faucets for valves. In fact, this is not the case. Faucets strictly belong to the bathroom series. Valves are divided into gate valves, globe valves, butterfly valves, high-pressure valves, low-pressure valves, fluorine-lined valves, safety valves, pressure relief valves, anti-corrosion valves, filters, check valves, pressure reducing valves, overflow valves, ceramic valves, medium pressure valve, high temperature valve, low temperature valve, etc.

Beginners to valves always mistake faucets for valves. In fact, this is not the case. Faucets strictly belong to the bathroom series. Valves are divided into gate valves, globe valves, butterfly valves, high-pressure valves, low-pressure valves, fluorine-lined valves, safety valves, pressure relief valves, anti-corrosion valves, filters, check valves, pressure reducing valves, overflow valves, ceramic valves, medium pressure valve, high temperature valve, low temperature valve, etc.

1. Classification

▍Based on power

1 automatic valve

A valve that relies on the power of the medium itself to operate. Such as check valves, pressure reducing valves, traps, safety valves, etc.

2 drive valve

Valves that rely on external forces such as manpower, electricity, hydraulic power, and pneumatic power to operate. Such as globe valve, throttle valve, gate valve, butterfly valve, ball valve, plug valve, etc.

▍According to structural characteristics

1. Portal shape: the closing piece moves along the center line of the valve seat.

2. Gate shape: the closing member moves along the center line perpendicular to the valve seat.

3. Plug shape: The closing member is a plunger or ball, which rotates around its center line.

4. Swing type: The closing member rotates around an axis outside the valve seat.

5. Butterfly: The closing member is a disc that rotates around the axis in the valve seat.

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

▍According to usage

1. For breaking: used to cut off or connect the pipeline medium. Such as stop valve, gate valve, ball valve, plug valve, etc.

2. For adjustment: used to adjust the pressure or flow of the medium. Such as pressure reducing valve and regulating valve.

3. Distribution: used to change the flow direction of the medium and play a distribution role. Such as three-way cock, three-way stop valve, etc.

4. Non-return: used to prevent the medium from flowing back. Such as check valve.

5. For safety: when the medium pressure exceeds the specified value, discharge the excess medium to ensure the safety of the equipment. Such as safety valves and emergency valves.

6. Used for gas blocking and drainage: retaining gas and removing condensation water. Such as drain valve.

▍According to operation method

1. Manual valve: a valve operated by human power with the help of handwheel, handle, lever, sprocket, gear, worm gear, etc.

2. Electric valve: a valve controlled by electricity.

3. Pneumatic valve: a valve operated by compressed air.

4. Hydraulic valve: a valve that uses liquids such as water and oil to transmit external force to operate.

▍Press pressure points

1. Vacuum valve: The only valve whose pressure is less than PN1.

2. Low-pressure valve: a valve whose nominal pressure is less than PN16.

3. Medium pressure valve: valve with nominal pressure PN25-PN64.

4. High-pressure valve: valve with nominal pressure

5. Ultra-high pressure: valves whose nominal pressure

▍According to medium temperature

1. Ordinary valves: suitable for valves with medium working temperature -40 to 450°C.

2. High-temperature valves: Suitable for valves with medium operating temperatures of 450 to 600°C.

3. Heat-resistant valves: suitable for valves with medium operating temperatures above 600°C.

4. Low-temperature valves: Suitable for valves with medium operating temperatures of -40 to -70°C.

5. Cryogenic valves: Suitable for valves with medium operating temperature of -70 to -196°C.

6. Ultra-low temperature valve: suitable for valves with medium working temperature below -196°C.

▍According to nominal diameter

1. Small-diameter valves: valves with a nominal diameter less than 40 mm.

2. Medium-diameter valves: valves with nominal diameters from 50 to 300 mm.

3. Large diameter valves: valves with nominal diameters from 350 to 1200 mm.

4. Extra large diameter valves: valves with a nominal diameter greater than 1400 mm.

  The above classification is not exhaustive and can also be classified from other perspectives, but mastering these basic classifications will be of great benefit to us in understanding the wide range of valves.