Beginners of valves always mistake faucets for valves. In fact, faucets strictly belong to the bathroom series. Valves are divided into gate valves, stop 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 valves, high-temperature valves, low-temperature valves, etc.

1. Classification

▍By power

1 Automatic valve

A valve that relies on the power of the medium itself to operate, such as a check valve, a pressure reducing valve, a steam trap, a safety valve, etc.

2 drive valve

A valve that is operated by external forces such as manpower, electricity, hydraulic power, or pneumatic power, such as stop valves, throttle valves, gate valves, butterfly valves, ball valves, and plug valves.

▍According to structural characteristics

1. Sectional gate shape: The closing part moves along the center line of the valve seat.

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

3. Plug type: The closing piece is a plunger or ball that rotates around its own center line.

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

5 Disc-shaped: The closing piece is a disc that rotates around the axis inside the valve seat.

6 Sliding valve type: The closing piece slides in a direction perpendicular to the channel.

 ▍By purpose

1. Disconnection: used to cut off or connect pipeline media. Such as stop valve, gate valve, ball valve, plug valve, etc.

2. 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. Check valve: used to prevent the medium from flowing back. Such as check valve.

5. Safety: When the medium pressure exceeds the specified value, the excess medium is discharged to ensure the safety of the equipment. Such as safety valve and emergency valve.

6. Gas blocking and drainage: retain gas and remove condensed water. Such as steam trap.

 ▍According to the operation method

1. Manual valve: A valve operated by manpower with the help of handwheel, handle, lever, sprocket, gear, worm gear, etc.

2 Electric valve: a valve operated by electricity.

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

4. Hydraulic valve: A valve that is operated by transmitting external force with the help of liquids such as water and oil.

▍ By pressure

1 Vacuum valve: A valve with a maximum pressure of less than 1 kg/cm2.

2 Low-pressure valve: valve with nominal pressure less than 16 kg/cm2.

3 Medium pressure valve: valve with nominal pressure of 25-64 kg/cm2.

4 High-pressure valve: valve with nominal pressure of 100-800 kg/cm2.

5 Ultra-high pressure: valve with nominal pressure reaching or exceeding 1000 kg/cm2.

▍ According to the medium temperature

1 Ordinary valve: valve suitable for medium working temperature of -40 to 450℃.

2 High temperature valve: valve suitable for medium working temperature of 450 to 600℃.

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

4 Low temperature valve: valve suitable for medium working temperature of -40 to -70℃.

5. Cryogenic valve: valve suitable for medium operating temperature of -70 to -196℃.

6 Ultra-low temperature valve: valve suitable for medium working temperature below -196℃.

 ▍According to nominal diameter

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

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

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

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