How to choose butterfly valve for large diameter water pipeline

In municipal water transmission and industrial water supply systems, large-diameter pipelines (DN600 and above) require valves with stable sealing performance, controllable operating torque and long service life.

Selecting an inappropriate valve construction may result in premature seat wear, leakage, or excessive actuator loading. The following technical factors should be considered when selecting butterfly valves for large-diameter water pipelines.

1. Valve structure: eccentric and concentric design

For large diameter applications, valve construction directly affects seal life and torque performance.

In a concentric butterfly valve, the disc remains in constant contact with the seat during operation. In high circulation or high pressure water systems, this may accelerate valve seat wear.

Double eccentric butterfly valve Reduce seat friction by allowing the disc to disengage from the seat shortly after opening. This structural feature improves sealing stability and extends service life of large diameter pipes.

2. Pressure Ratings and Surge Considerations

Water delivery systems may experience pressure fluctuations and hydraulic fluctuations.

The selected valve pressure rating (e.g., PN10, PN16, or PN25) should match the pipeline design pressure, including potential surge margin.

Underestimating a valve can increase leakage risk and structural stress, while excessive overestimation can unnecessarily increase procurement costs.

Engineering verification of operating pressure conditions is critical before final selection.

3. Seal type and seat configuration

Seat design significantly affects long-term performance.

Key considerations include:

• Comparison of soft seats and metal seats
• Interchangeable seat structure
• Two-way sealing requirements

In water delivery systems, replaceable valve seat designs can reduce life cycle maintenance costs. For applications involving higher temperatures or abrasive media, metal seat options may be considered.

The valve seat material should also be evaluated for compatibility with water quality and treatment chemicals.

4. Torque requirements and driving methods

Large diameter valves require careful evaluation of operating torque.

High torque possible:

• Increase actuator size
• Increase installation costs
• Affects automation reliability

Offset valve structures generally provide lower frictional resistance compared to concentric designs, which is beneficial for actuator drive systems in pumping stations and municipal networks.

Manual, gearbox operation or electric drive mode should be selected depending on project requirements.

5. Material selection and corrosion resistance

Compatibility of materials with the pipeline environment is critical.

Common considerations include:

• Ductile iron valve body for municipal water supply
• Carbon steel or stainless steel for industrial systems
• Corrosion resistant protective coating
• Shaft and fastener material strength

For harsh water environments or coastal areas, corrosion resistance becomes the main selection factor.

6. Maintenance strategies and life cycle costs

The initial purchase cost is only part of the evaluation.

Large diameter valves in municipal infrastructure are expected to operate for a long service life. Ease of maintenance, accessibility for seat replacement and availability of spare parts should be considered when choosing.

Valves designed for reduced seat friction and stable structural support can reduce the frequency of long-term maintenance.

Selecting a butterfly valve for large diameter water pipes requires an evaluation of structural design, pressure rating, seal configuration, torque performance and material compatibility.

Engineering-based choices reduce leak risks, minimize maintenance costs, and improve the long-term operational reliability of municipal and industrial water systems.

RKSfluid s double eccentric butterfly valve series is designed to meet the performance requirements of large-diameter water transmission projects. For detailed technical specifications or project inquiries, please contact our engineering team.