Rubber Sphere for Rubber Expansion Joint, Main Body

Product Overview

The rubber sphere is the main elastic body of flexible rubber expansion joint, also known as rubber soft joint or vibration isolator. It is integrally vulcanized under high temperature and pressure without glued seams, which effectively prevents leakage and delamination. Steel wire rings are embedded in the flange bead on both ends to avoid bead flipping, disengagement and separation from flanges under pressure. The inner high-strength cord fabric bears the working pressure and prevents bulging. This rubber sphere can be supplied separately for replacement of damaged old joints. It can also be assembled with flanges, limit tie rods and bolts to form a complete rubber expansion joint. It is flexible for spare parts stock and new project supporting.

Structure & Material

The sphere adopts a three-layer composite structure. The inner rubber layer is dense and medium-resistant, with smooth surface to resist scaling and corrosion. The middle layer is multi-layer cross-laid polyester or nylon cord fabric reinforcement. The number of cord layers is adjusted according to pressure rating to withstand internal pressure. The outer rubber layer is weather-resistant, protecting the sphere from ozone, UV, rain, dust and minor mechanical damage. Multiple rubber materials are optional: NR natural rubber for normal temperature water with good elasticity and low cost; EPDM for hot water, weak acid and alkali, widely used in HVAC and water treatment; NBR oil-resistant rubber for oil and fuel pipelines; FKM fluororubber for high temperature and strong corrosive conditions. PTFE lining is available for severe chemical service. We provide single sphere, double sphere and reducing sphere types. Double sphere achieves larger displacement compensation while reducing sphere connects pipes of different diameters directly.

Performance & Application

Thanks to its excellent elasticity, the rubber sphere compensates axial expansion, lateral offset and angular deflection of pipelines. It absorbs thermal stress from temperature change and tolerates installation misalignment, protecting pumps, valves and pipelines from extra mechanical load. It isolates vibration transmitted from pumps, fans and compressors and reduces fluid noise. It features good anti-fatigue and anti-aging performance, and can absorb water hammer impact to protect instruments and precision equipment. It is widely used in water supply & drainage, HVAC, fire protection, sewage treatment, chemical industry, power plant, metallurgy and oil & gas pipelines. It is commonly installed in pump rooms, heat exchange stations, equipment rooms and outdoor buried pipelines for municipal, industrial and construction piping flexible connection.