Rubber expansion joints are widely used in piping systems for water supply, HVAC, pump rooms, and air conditioning. They help absorb vibration, compensate for displacement, and reduce noise. However, leakage problems sometimes occur during operation, which may seriously affect the safety of the entire system.
Root Cause of Leakage: Improper Flange Connection
The sealing performance of a rubber expansion joint largely depends on the quality of its connection with the pipeline flanges. In most leakage cases, the problem is not with the rubber joint itself, but rather with improper flange selection or incorrect installation. For example, using a standard flat welding flange with a rubber joint can result in poor sealing due to mismatched inner diameters or uneven sealing surfaces—leading to leakage, noise, or even joint rupture.
Technical Solution: Use Butterfly Valve Dedicated Flanges
To solve sealing issues effectively, we recommend using butterfly valve dedicated flanges, also known as “butterfly flanges” or “soft-seal flanges.” These flanges are specifically designed to match rubber expansion joints and offer the following advantages:
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Perfect Inner Diameter Matching: The inner diameter of the flange matches exactly with the rubber joint, ensuring smooth fluid flow and preventing turbulence that may cause leakage.
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Smooth and Flat Sealing Surface: The flange contact surface is precisely machined to be flat and smooth, providing a 100% sealing fit with the rubber joint.
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Designed for Soft Seals: The structure of the flange accommodates the flexibility of rubber joints, maintaining strong sealing performance even under high pressure or vibration.
Installation Notes
When using butterfly valve flanges with rubber expansion joints, please pay attention to the following:
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Ensure a tight, clean contact between the rubber joint and the flange with no debris in between.
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Tighten bolts symmetrically in a crisscross pattern to prevent uneven stress and deformation of the sealing surface.
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Regularly inspect flange surfaces for rust or scratches that could affect sealing.
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Use suitable gasket materials as needed to enhance overall sealing performance.
Conclusion
Rubber expansion joints are mature and reliable products. Leakage issues usually stem from improper flange selection or installation errors. Using butterfly valve dedicated flanges is a proven method to improve sealing performance and extend product lifespan. We encourage all users to follow technical guidelines during installation to maximize the effectiveness of rubber expansion joints.
For more technical support and product specifications, please contact:
Shanghai Songjiang Shock Absorber Group Co., Ltd. – Technical Support Department
📧 Email: [email protected]
🌐 Website: www.shsjflex.com
📱 WhatsApp: +86 13032112360
