What is the Difference Between a Bolted and a Welded Bonnet Gate Valve?

Introduction

Gate valves are essential in fluid isolation applications, and the bonnet design plays a critical role in valve integrity, pressure handling, and maintenance. Two popular types are bolted bonnet and welded bonnet gate valves—but what sets them apart?

Bolted Bonnet Gate Valves

• Structure: The bonnet is attached to the valve body using bolts and a gasket.

• Advantages: Easy disassembly for inspection and maintenance.

• Applications: Suitable for systems requiring frequent servicing or part replacement.

• Pressure Rating: Typically used in medium-pressure applications.

Welded Bonnet Gate Valves

• Structure: The bonnet is permanently welded to the body, forming a seal without gaskets.

• Advantages: No potential for gasket leaks; compact and ideal for high-pressure/high-temperature systems.

• Applications: Common in applications where maintenance access is limited or not required frequently.

• Pressure Rating: Designed for high-pressure environments.

Key Differences

Conclusion

Choosing between bolted and welded bonnet gate valves depends on your system’s pressure, temperature, and maintenance requirements. Bolted types offer flexibility, while welded types offer long-term sealing reliability.