double spheres rubber expansion joint

# Double Sphere Rubber Expansion Joint – Product Overview
## Key Features & Benefits
**Superior Displacement Compensation** – The double-sphere configuration allows for axial compression and extension, lateral deflection, and angular movement, accommodating pipeline shifts caused by thermal expansion, foundation settlement, or equipment vibration. Compared to single-sphere joints, the double-sphere design provides enhanced displacement capacity.
**Vibration Damping & Noise Reduction** – The rubber body effectively absorbs mechanical vibrations from pumps, compressors, and other rotating equipment. When installed between vibrating machinery and rigid metal pipes, it can reduce structure-borne noise by 15 to 25 decibels.
**Pressure Resistance & Durability** – The multi-layered nylon cord reinforcement provides high tensile strength, enabling the joint to withstand high internal pressures without deformation or bursting. Working pressures typically range up to 1.0 to 2.5 MPa (10 to 25 bar), with corresponding burst pressures up to 4.5 MPa.
**Easy Installation & Maintenance** – Lightweight and compact, the joint requires minimal space. The self-sealing full-face rubber flange eliminates the need for separate gaskets. Rotating flanges simplify alignment with piping systems.
**Long Service Life** – When installed indoors under normal conditions, the product can provide up to 20 years of reliable service.
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## Materials & Construction
The joint features an inner and outer rubber layer available in multiple material grades to suit different media, including Natural Rubber (NR), Nitrile Rubber (NBR), EPDM, Neoprene, Hypalon, and Viton. The reinforcement layer consists of multi-ply nylon cord fabric with a bias-ply tire cord construction for maximum strength. A steel wire or solid steel pressure ring is incorporated to prevent vacuum collapse. Flanges are available in carbon steel with galvanized or zinc-plated finish, as well as stainless steel options.
For material selection, EPDM is recommended for water, seawater, hot water, moderate chemicals, and applications requiring weathering and ozone resistance. NBR (Nitrile) is ideal for oil, grease, and petroleum-based media. Neoprene serves as a good all-purpose material with resistance to moderate chemicals, oils, and sunlight. Natural Rubber is suitable for air, water, and abrasive applications.
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## Performance Specifications
The product is available in size ranges from DN32 to DN1200, corresponding to 1¼ inches through 48 inches. Working pressure ratings typically range from 1.0 to 2.5 MPa (10 to 25 bar), with burst pressures reaching 2.0 to 5.5 MPa. The vacuum rating can achieve up to 86.7 kPa (650 mmHg). Standard temperature range is from -15°C to +115°C, with special grades available for extreme conditions from -30°C up to +250°C.
In terms of movement capabilities, axial compression can reach up to 25 to 30 millimeters depending on size, while axial extension ranges up to 16 to 18 millimeters. Lateral deflection capacities range from 22 to 45 millimeters, and angular deflection can accommodate up to 30 to 35 degrees. It is important to note that specific dimensions and ratings vary by manufacturer and size, so users are advised to refer to the product datasheet for detailed technical specifications.
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## Flange Standards & Drilling Options
The double sphere rubber expansion joint is available with flanges drilled to meet major international standards, including ANSI and ASME B16.5 for Class 150 and 300 ratings, EN and DIN standards for PN10, PN16, and PN25, BS-10 British Standard, JIS 10K and 16K, as well as AWWA standards for water works applications. Custom drilling patterns are also available upon request to accommodate specific project requirements.