Valve "Encyclopedia"

1. Valve Knowledge Encyclopedia

Valves are indispensable in modern industry and daily lifeMechanical devices. It is used to control the flow of fluid, and realizes the delivery, regulation and control of fluid by regulating, opening, closing or blocking fluid channels. Valves are widely used in many fields such as oil, natural gas, chemical industry, water treatment, and construction facilities.

2. Basic concepts of valves

definition:
A valve is a device that regulates, guides and controls the flow of fluid through mechanical devices. It is usually composed of a valve body, valve cover, valve stem, valve seat, seal and other parts.

How it works:
The valve drives the valve stem through manual, pneumatic, electric or hydraulic methods, so that the valve core or valve plate can move accordingly (such as rotation, lift, slide) in the valve body, thereby changing the size of the fluid channel and realizing the opening, closing and adjustment of the fluid.

3. The main functions of the valve

Flow control:
The flow of fluid is controlled by adjusting the opening of the valve to meet the process requirements.

Flow control:
Change the flow direction of the fluid to ensure that the fluid flows in a predetermined path.

Pressure control:
Adjust and control the pressure in the piping system to keep the system running within a safe pressure range.

Media isolation:
Completely close part of the piping system, prevent fluid flow, and achieve system isolation for easy overhaul and maintenance.

Prevent backflow:
Prevent fluid backflow and protect the safety of the system and equipment.

4. Classification of valves

According to different classification standards, valves can be divided into many types:

1. Classified by function:

Gate Valve:Used to turn on or close fluid channels, usually suitable for systems that do not require frequent operation.

Ball Valve:passRotate a sphere with holes to control fluid flow, suitable for systems that require quick opening and closing.

Butterfly Valve:Adjust flow by rotating a disc, suitable for large diameter and low pressure applications.

Check Valve:Prevent fluid backflow and ensure that the fluid flows in only one direction.

Safety Valve:When the system pressure exceeds the preset value, it will automatically turn on, releasing excessive pressure to protect the system safety.

Pressure Reducing Valve:Depress the high-pressure fluid to the set low pressure to maintain stable operation of the system.

2. Classified by drive method:

Manual valve:Open and close the valve by manually operating the valve stem.

Pneumatic valve:The valve is controlled by driving the actuator through compressed air.

Electric valve:The valve opening and closing is controlled by an electric actuator.

Hydraulic valve:The valve is controlled by a hydraulically driven actuator.

5. Structural characteristics of common valves

1. Gate Valve:The structure is simple, the fluid resistance is small, but the opening and closing are slow, and it is suitable for fully open or fully closed conditions.

2. Ball Valve:It has a compact structure, low fluid resistance, and is quickly opened and closed, and is suitable for working conditions that require frequent operation and rapid opening and closing.

3. Butterfly Valve:It has a simple structure, light weight and low cost, but has low fluid control accuracy and is suitable for large-diameter pipelines.

4. Check Valve:Automatically operates to prevent backflow of fluid. It has a simple structure but high resistance.

5. Safety Valve:Automatically turn on and off to ensure the safety of the system, but requires regular checksum maintenance.

6. Application areas of valves

Oil and gas industry:Control the mining of crude oil and natural gas,输送and processing process.

Chemical Industry:Used for flow and pressure control of various chemical media.

Water treatment:Used for water delivery, treatment and distribution systems.

Energy Industry:Used for fluid control systems for power plants, nuclear power plants, etc.

Building facilities:Used for water supply, heating, air conditioning and other systems.

7. Conclusion
Valves play a crucial role in modern industry and daily life. It can not only effectively control the flow, pressure and flow direction of the fluid, but also improve the safety and operating efficiency of the system. When selecting and using valves, you need to select the appropriate type and specifications according to the specific application scenario and needs to ensure optimal performance and reliability. Understanding the basic knowledge and functions of valves can help better maintain and manage fluid control systems.