double block &bleed plug valve | Classification of valves
01 Jan

double block &bleed plug valve | Classification of valves

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 and so on.
1. Classification
▍According to power points
1 automatic valve
A valve that operates on the strength of the medium itself. Such as check valves, pressure reducing valves, traps, safety valves, etc.
2 Drive the valve
Valves operated by external forces such as manpower, electric power, hydraulic power, and pneumatic power. Such as globe valve, throttle valve, gate valve, butterfly valve, ball valve, plug valve, etc.

▍According to structural characteristics
1. Sectional door shape: The closing piece moves along the center line of the valve seat.
2. Gate shape: The closing piece moves along the center line perpendicular to the valve seat.
3. Cock shape: The closing part is a plunger or a ball, which rotates around its centerline.
4. Swing shape: The closing piece rotates around an axis outside the valve seat.
5. Butterfly shape: The closing part is a disc, which rotates around the axis in the valve seat.
6. Slide valve shape: The closing piece slides in the direction perpendicular to the channel.

▍According to purpose
1. For breaking: used to cut off or connect pipeline medium. Such as cut-off 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, regulating valve.
3. Distribution: used to change the flow direction of the medium and play a role in distribution. Such as three-way cock, three-way stop valve, etc.
4. Non-return use: used to prevent the medium from flowing back. Such as a check valve.
5. For safety: When the medium pressure exceeds the specified value, discharge excess medium to ensure the safety of the equipment. Such as safety valve, accident valve.
6. Gas barrier drainage: retain gas and remove condensed water. Such as traps.

▍According to the operation method
1. Manual valve: The valve is operated by manpower with the help of handwheels, handles, levers, sprockets, gears, worm gears, etc.
2. Electric valve: a valve operated by electric power.
3. Pneumatic valve: a valve operated by means of compressed air.
4. Hydraulic valve: The valve is operated by transferring external force with the help of water, oil and other liquids.

▍Press pressure points
1. Vacuum valve: a valve whose absolute pressure is less than PN1.
2. Low pressure valve: a valve whose nominal pressure is less than PN16.
3. Medium pressure valve: the valve with nominal pressure PN25-PN64.
4. High-pressure valve: a valve with a nominal pressure of PN100-PN800.
5. Ultra-high pressure: the valve whose nominal pressure reaches or exceeds PN1000.

▍According to the temperature of the medium
1. Ordinary valve: suitable for valves with medium working temperature -40 to 450°C.
2. High temperature valve: suitable for valves with a working temperature of 450 to 600 ℃.
3. Heat-resistant valve: suitable for valves whose working temperature is above 600℃.
4. Cryogenic valve: suitable for valves with medium working temperature of -40 to -70°C.
5. Cryogenic valve: suitable for valves with medium operating temperature -70 to -196°C.
6. Ultra-low temperature valve: suitable for valves whose working temperature is below -196℃.

▍According to the nominal diameter
1. Small-caliber valve: a valve with a nominal diameter less than 40 mm.
2. Medium-caliber valves: valves with a nominal diameter of 50 to 300 mm.
3. Large-diameter valves: valves with a nominal diameter of 350 to 1200 mm.
4. Extra large diameter valves: valves with a nominal diameter greater than 1400 mm.

The above classification is not absolute, it can also be classified from other angles, but mastering these basic classifications is of great benefit to our understanding of a wide range of valves.