Introduction to Valve Connection Methods

Overview

In the design and manufacturing of valves, the connection method between the valve body and the bonnet is crucial. It directly affects the valve's performance, reliability, and ease of maintenance. Below is a detailed introduction to several common connection methods, along with their characteristics and application ranges.

1. Threaded Connection

• Characteristics: Threaded connections can be divided into internal and external threads. This method is simple and compact, making it easy to install. However, the threads are prone to corrosion, which can make disassembly difficult once rust occurs.
• Application Range: Typically used in low-pressure environments for small valves, such as household water taps.

2. Flanged Connection

• Characteristics: Flanged connections are often integrated with the valve body. While they tend to be larger in size, they are easy to disassemble and provide reliable sealing. Additionally, flanged connections allow for convenient inspection and maintenance.
• Application Range: Widely used across various pressure levels and valve sizes, from low-pressure to high-pressure applications, and from small to large-diameter valves.

3. Clamp Connection

• Characteristics: A clamp connection does not require a flange. It only requires two bolts for assembly, making installation and disassembly quick and convenient. While more compact than flanged connections, its complex structure and higher machining difficulty make it less commonly used in practice.
• Application Range: Primarily used in medium to high-pressure environments for large-diameter valves, such as certain applications in industrial piping systems.

4. Welded Connection

• Characteristics: Welding is a permanent connection method, providing extremely high sealing reliability. However, if internal valve components are damaged and cause leakage, the non-detachable nature of welded connections makes repairs more complicated.
• Application Range: Suitable for situations that require extremely high sealing reliability and do not require frequent maintenance or replacement, such as key components in nuclear power plants.

5. Pressure-Sealed Connection

• Characteristics: Pressure-sealed structures rely on the pressure of the fluid itself to form a seal. As the pressure of the medium increases, the sealing effect becomes stronger, making this method ideal for extreme conditions.
• Application Range: Particularly suitable for high-temperature and high-pressure valve applications, such as high-pressure valves in the petrochemical industry.

Conclusion

From the above descriptions, it is clear that each connection method has its own advantages and disadvantages, and is suited for different applications. Choosing the right connection method is crucial to ensuring the stable operation of the valve throughout its service life.

FAQs

1. What are the most common valve connection methods used in industrial applications?
   • Flanged and welded connections are the most commonly used methods in industrial applications due to their reliability and versatility.
2. What challenges can arise with threaded connections?
   • Threaded connections can suffer from corrosion, making them difficult to disassemble, especially in harsh environments.
3. Why is welding not suitable for valves that require frequent maintenance?
   • Welded connections are permanent, making disassembly for repairs or maintenance highly challenging and time-consuming.
4. In what situations are pressure-sealed connections most effective?
   • Pressure-sealed connections are most effective in high-temperature and high-pressure environments, where increased pressure enhances the sealing effect.
5. How does a clamp connection compare to a flanged connection?
   • A clamp connection is more compact and faster to install but is less commonly used due to its complex structure and higher machining difficulty compared to flanged connections.

By considering the specific operating conditions and maintenance needs, selecting the appropriate connection method can greatly enhance the valve's performance and longevity.