Single Sphere EPDM Rubber Expansion Joint DN15-DN4000 PN16 Carbon Steel Epoxy Flange

This single sphere rubber expansion joint is built around a moulded EPDM body that is vulcanised together with a nylon cord fabric reinforcement and a steel wire strand pressure ring. The combination gives the sphere its shape memory under internal pressure, so the joint keeps its arch profile even after thousands of pump start and stop cycles. Both ends are fitted with carbon steel flanges finished with an epoxy coating that resists condensation, splash water and mild chemical splash in plant rooms.

Because the sphere is free to flex in all directions, the joint absorbs axial compression and extension, lateral offset and angular deflection in a single fitting. That freedom removes the need for precision pipe alignment on site and takes the stress out of pump nozzles, tank connections and riser transitions. The smooth inner bore stays flush with the flange face, so there is no step for sediment to collect and no reduction in flow area.

• Wide Size Coverage: One-piece moulded sphere available from DN15 up to DN4000, allowing a single specification to serve small branch lines and large transmission mains alike.
• Epoxy Coated Flanges: Carbon steel flanges receive a baked epoxy coating for corrosion protection in damp plant rooms, coastal air and lightly aggressive service water.
• Four-Way Movement: Axial, lateral and angular movement plus torsional deflection are all handled by the spherical arch, protecting anchors and pump casings.
• Pressure Reinforced Arch: The steel wire pressure ring and multi-ply nylon cord carcass hold the sphere against internal pressure up to PN16 with a 1.5 times hydrostatic test.
• Rotating Flange Option: Loose flange rings can be rotated on site so bolt holes line up with existing DIN, ANSI, JIS or BS counter flanges without re-drilling.
• Noise and Vibration Cut: The rubber wall breaks the structure-borne path between pump and pipework, reducing transmitted noise and mechanical vibration noticeably.

Typical installations are chilled and hot water circuits, municipal water supply lines, sewage lift stations, cooling tower connections and pump suction and discharge headers. The joint is equally at home on marine cooling systems and on irrigation mains where ground settlement would otherwise crack a rigid spool. Where the pipeline carries abrasive slurry, we recommend a wear sleeve so the rubber wall is not scoured by the flow.

Each joint is hydrostatically tested before it leaves the line, then wrapped in plastic film, boxed in carton and loaded into a wooden case measuring approximately 1100mm x 1100mm x 1100mm. Flange faces are protected with soft gaskets during transport. We supply a mill test certificate, dimensional report and pressure test record with every shipment, and the product is produced under our ISO 9001 quality system.