1. Classification by function and use

(1) Cut-off valve: Cut-off valve is also called a closed-circuit valve. Its function is to connect or cut off the medium in the pipeline. Cut-off valves include gate valves, globe valves, plug valves, ball valves, butterfly valves and diaphragm valves, etc.

(2) Check valve: Check valve is also called one-way valve or check valve. Its function is to prevent the medium in the pipeline from flowing back. The bottom valve of the water pump suction valve also belongs to the check valve category.

(3) Safety valve: The function of the safety valve is to prevent the medium pressure in the pipeline or device from exceeding the specified value, thereby achieving the purpose of safety protection.

(4) Regulating valve: Regulating valves include regulating valves, throttle valves and pressure reducing valves. Their function is to regulate the pressure, flow and other parameters of the medium.

(5) Diverter valve: Diverter valves include various distribution valves and traps, etc., and their function is to distribute, separate or mix the media in the pipeline.

(6) Exhaust valve: The exhaust valve is an essential auxiliary component in the pipeline system and is widely used in boilers, air conditioners, oil and gas, water supply and drainage pipelines. It is often installed at commanding heights or elbows to eliminate excess gas in pipelines, improve pipeline efficiency and reduce energy consumption.

2. Classification by nominal pressure

(1) Vacuum valve: refers to a valve whose working pressure is lower than the standard atmospheric pressure.

(2) Low-pressure valve: refers to valves with nominal pressure PN ≤1.6Mpa.

(3) Medium pressure valve: refers to valves with nominal pressure PN of 2.5, 4.0, and 6.4Mpa.

(4) High-pressure valve: refers to a valve with a nominal pressure PN of 10 to 80Mpa.

(5) Ultra-high pressure valve: refers to valves with nominal pressure PN≥100Mpa.

3. Classification according to working temperature

(1) Ultra-low temperature valve: valve used for medium working temperature tlt; -100℃.

(2) Low temperature valve: used for valves with medium working temperature -100℃≤t≤-40℃.

(3) Normal temperature valve: used for valves with medium operating temperature -40℃≤t≤120℃.

(4) Medium temperature valve: used for medium working temperature 120℃

(5) High temperature valve: used for valves with medium working temperature tgt; 450℃.

4. Classification by driving method

(1) Automatic valves refer to valves that do not require external driving, but rely on the energy of the medium itself to operate the valve. Such as safety valves, pressure reducing valves, traps, check valves, automatic regulating valves, etc.

(2) Power-driven valve: Power-driven valve can be driven by various power sources.

Electric valve: A valve driven by electricity.

Pneumatic valve: A valve driven by compressed air.

Hydraulic valve: A valve driven by pressure from a liquid such as oil.

In addition, there are combinations of the above driving methods, such as gas-electric valves, etc.

(3) Manual valve: Manual valve uses handwheel, handle, lever and sprocket to control the valve action manually. When the valve opening and closing torque is large, this wheel or worm gear reducer can be installed between the handwheel and the valve stem. When necessary, universal joints and drive shafts can also be used for remote operations.

5. Classification by nominal diameter

(1) Small diameter valves: valves with nominal diameter DN≤40mm.

(2) Medium diameter valve: a valve with a nominal diameter DN of 50 to 300mm.

(3) Large diameter valve: a valve with a nominal valve DN of 350 to 1200mm.

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

6. Classification by structural characteristics

(1) Globe valve: the closing part moves along the center of the valve seat;

(2) Plug valve: the closing part It is a plunger or ball that rotates around its center line;

(3) Gate shape: the closing member moves along the center of the vertical valve seat;

(4) Swing valve: The closing member rotates around the axis outside the valve seat;

(5) Butterfly valve: the disc of the closing member rotates around the axis inside the valve seat;

(6) Slide valve: closed The piece slides in a direction perpendicular to the channel.

7. Classification by connection method

(1) Threaded connection valve: The valve body has internal threads or external threads and is threadedly connected to the pipe.

(2) Flange connection valve: The valve body is equipped with a flange and is connected to the pipe flange.

(3) Welded connection valve: The valve body has a welding groove and is welded to the pipe.

(4) Clamp connection valve: The valve body is equipped with a clamp port and is connected to the pipe clamp.

(5) Card sleeve connection valve: Use a card sleeve to connect to the pipe.

(6) Clamp connection valve: a connection form in which the valve and the pipes at both ends are directly clamped together with bolts.

8. Classification by valve body material

(1) Metal material valves: The valve body and other parts are made of metal materials. Such as cast iron valves, carbon steel valves, alloy steel valves, copper alloy valves, aluminum alloy valves, lead alloy valves, titanium alloy valves, Monel alloy valves, etc.

(2) Non-metallic material valves: The valve body and other parts are made of non-metallic materials. Such as plastic valves, ceramic valves, enameled valves, fiberglass valves, etc.

(3) Metal valve body lined valve: The valve body is made of metal, and all the main internal surfaces in contact with the medium are lined, such as rubber-lined valves, plastic-lined valves, ceramic-lined valves, etc.

9. Valve model arrangement

The valve model should usually indicate the valve type, driving method, connection form, structural characteristics, sealing surface material, valve body material and nominal pressure and other factors. The standardization of valve models facilitates the design, selection, and sales of valves. Today, there are more and more types and materials of valves, and the model system of valves is becoming more and more complex. Although my country has a unified standard for valve model compilation, it is increasingly unable to meet the needs of the development of the valve industry. At present, valve manufacturers generally use a unified numbering method; if a unified numbering method cannot be used, each manufacturer will develop a numbering method according to its own needs.

"Valve Model Preparation Method" is applicable to gate valves, throttle valves, ball valves, butterfly valves, diaphragm valves, plunger valves, plug valves, check valves, safety valves, pressure reducing valves, and drains for industrial pipelines. valve. It includes the valve model number and the valve naming.

Valves have a wide range of uses, many types, and many classification methods. Generally speaking, it can be divided into two categories:

The first type of automatic valve: a valve that relies on the ability of the medium (liquid, gas) itself to act on its own. Such as check valves, safety valves, regulating valves, traps, pressure reducing valves, etc.

The second type of driven valve: a valve that uses manual, electric, hydraulic, or pneumatic controls to operate. Such as gate valves, globe valves, throttle valves, butterfly valves, ball valves, plug valves, etc.

In addition, there are several ways to classify valves:

1. According to structural characteristics, they can be divided according to the direction of movement of the closing member relative to the valve seat:

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

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

3. Plug and ball: The closing member is a plunger or ball that rotates around its center line.

4. Swing type; the closing member rotates around the axis outside the valve seat.

5. Disc: The disc of the closing member rotates around an axis within the valve seat.

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

According to the type of structure, they mainly include:

Plug valve, gate valve, globe valve, ball valve - used to open or close the flow of media in pipelines.

Check valve (including foot valve) - used to automatically prevent the backflow of media in the pipeline. Throttle valve - used to regulate the flow of pipeline media.

Butterfly valve - used to open or close the medium in the pipeline. It can also be used for adjustment.

Safety valve - used in boilers, containers, equipment and pipelines. When the medium pressure exceeds a specified value, it can automatically eliminate excess medium pressure to ensure safe production and operation.

Pressure reducing valve - used to automatically reduce the pressure of the medium in pipelines and equipment. When the medium passes through the gap of the valve disc, resistance is generated and pressure loss is achieved to achieve the purpose of pressure reduction.

Drain trap - used to automatically remove condensed water from steam pipelines to prevent steam loss or leakage.

2. According to the purpose, the valves can be divided into different uses:

1. For breaking: used to connect or cut off pipeline media, such as globe valves, gate valves, and ball valves , butterfly valve, etc.

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

3. For regulation: used to regulate the pressure and flow of the medium, such as regulating valves and pressure reducing valves.

4. Distribution: used to change the flow direction of the medium and distribute the 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 the pipeline system and equipment, such as safety valves and emergency valves.

6. Other special uses: such as traps, vent valves, sewage valves, etc. lt;![endif]gt;

Classified by purpose and function

Cut-off valves - mainly used to cut off or connect the flow of media. Including gate valves, globe valves, diaphragm valves, ball valves, plug valves, butterfly valves, plunger valves, ball plug valves, needle instrument valves, etc. Regulating valves - mainly used to regulate the flow and pressure of media. Including regulating valves, throttle valves, pressure reducing valves, etc.

Check valve - used to prevent the backflow of media. Including check valves of various structures.

Diversion valve - used to separate, distribute or mix media. Including distribution valves and traps of various structures.

Safety valves - used for safety protection when medium overpressure. Includes various types of safety valves.

3. According to the driving mode, it can be divided into different driving modes:

1. Manual: with the help of handwheel, handle, lever or sprocket, etc., it is driven by human power and the transmission is relatively slow. When the torque is high, reduction devices such as worm gears and gears are installed.

2. Electric: driven by a motor or other electrical device.

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

4. Pneumatic; driven by compressed air.

4. Pressing pressure can be divided according to the nominal pressure of the valve:

1. Vacuum valve: absolute pressure lt; 0.1MPa, which is a valve with a height of 760mm mercury, usually mm mercury Column or mm

A column of water represents pressure.

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

3. Medium pressure valve: nominal pressure PN2.5-6.4 MPa valve.

4. High-pressure valve: valve with nominal pressure PN10.0-80.0MPa.

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

5. According to the temperature of the medium, the valve can be divided according to the temperature of the medium when it is working:

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

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

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

4. Low temperature valve: suitable for valves with medium temperature of -40~-150℃.

5. Ultra-low temperature valve: suitable for valves with medium temperature below -150℃.

6. According to the nominal diameter, the valve can be divided according to its nominal diameter:

1. Small diameter valve: nominal diameter DNlt; 40mm valve.

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

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

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

7. According to the connection method with the pipeline, the valve can be divided according to the connection method with the pipeline;

1. Flange connection valve: the valve body has a flange and is connected to the pipeline using the method Orchid connected valve.

2. Threaded connection valve: The valve body has internal threads or external threads and is threadedly connected to the pipeline.

3. Welded connection valve: The valve body has a welding port and is welded to the pipeline.

4. Clamp connection valve: a valve with a clamp on the valve body and connected to the pipeline by a clamp.

5. Cutting sleeve connection valve: a valve that uses a cutting sleeve to connect to the pipeline.

Classification by valve body material

Non-metal material valves - such as ceramic valves, fiberglass valves, plastic valves.

Metal material valves - such as copper alloy valves, aluminum alloy valves, lead alloy valves, titanium alloy valves, Monel alloy valves, cast iron valves, carbon steel

Valves, cast steel Valves, low alloy steel valves, high alloy steel valves.

Metal body lined valves - such as lead lined valves, plastic lined valves, and enamel lined valves.

General classification method

This classification method is divided according to principles, functions and structures. It is currently the most commonly used classification method internationally and domestically. General gate valves, globe valves, throttle valves, instrument valves, plunger valves, diaphragm valves, plug valves, ball valves, butterfly valves, check valves, pressure reducing valves, safety valves, traps, regulating valves, bottom valves, filters, Drainage valve, etc. Because the valve has a wide range of uses, it also plays a great role. For example: in power plants, valves can control the operation of boilers and steam turbines; in petroleum and chemical production, valves also play a role in controlling the normal operation of all production equipment and processes. The same is true in other departments. Despite this, valves are often overlooked compared with other products. For example: when installing machinery and equipment, people often focus on the main machinery and equipment, such as compressors, high-pressure vessels, boilers, etc.; some are also improperly selected... These practices will reduce the entire production efficiency or stop production, or cause various other accidents. Therefore, the selection, installation, and use of valves must be done carefully and responsibly. This is especially true for modern industrial production and construction