1. Rubber flexible bellows body: Multi-layer composite structure with inner rubber sealing layer, multi-layer high-strength nylon cord fabric reinforcement layer, outer weather-resistant rubber protective layer; single sphere, double sphere and triple sphere types are optional according to displacement demand.
2. Connecting flanges: Carbon steel galvanized, stainless steel 304/316 integral flanges, available in GB, DIN, ANSI, JIS standard drilling patterns, flat full-face sealing design to eliminate leakage risk.
3. Limit restraint assembly: Symmetrically welded limit lugs on both flanges, matched with Grade 8.8 galvanized or stainless steel tie rods, double lock nuts at both ends, and spherical self-aligning gaskets.
4. Auxiliary accessories: Anti-slip flat washers, anti-loose spring gaskets, adjustable limit stoppers for fine-tuning allowable stretching distance. All components are pre-assembled and factory-calibrated, supporting direct on-site installation without secondary welding or modification.

2. Core Displacement Compensation & Vibration Isolation Performance

• Axial movement: Absorb axial elongation caused by medium temperature rise and axial compression during pipeline cooling; standard displacement ranges cover 6–35mm based on DN size.
• Lateral transverse offset: Tolerate horizontal misalignment from construction installation deviation, foundation settlement and equipment displacement.
• Angular deflection: Allow small-angle deflection between two flanges to adapt to non-parallel pipeline layout. Meanwhile, the multi-layer cord rubber structure effectively cuts off vibration transmission from pumps, fans and compressors to the whole pipe network, reduces pipeline resonance noise by over 30dB, and releases concentrated thermal stress to protect valves, pumps and pipe fittings from fatigue cracking. It features smooth full bore with low fluid resistance, no medium deposition inside.

  3. Unique Safety Protection Function of Limit Tie Rod System

  The limit tie rod set is the core safety upgrade compared to ordinary unrestrained rubber expansion joints, with multi-layer protection logic:
  1. Displacement limit calibration: Adjust the double lock nuts to preset the maximum safe stretching length of the rubber sphere, strictly restrict the expansion joint within the design displacement range during normal operation.
  2. Anti-pull-off protection against pressure thrust: Under high working pressure (PN10/PN16), water hammer instantaneous impact or pipe anchor failure, the tie rods bear all axial tensile thrust instead of the rubber body, preventing over-stretching, rubber delamination, tearing and pipeline separation accidents.
  3. Allow normal flexible movement: Spherical gaskets reserve space for lateral and angular offset; the rods only lock extreme elongation without restricting the joint’s basic shock absorption and compensation functions.
  4. Secondary safety backup: Even if the rubber bellows is damaged by unexpected overload, the symmetric tie rods can temporarily connect two pipe sections to avoid medium leakage and pipeline collapse, winning maintenance time for the system.

  4. Diversified Material Matching & Comprehensive Medium Adaptability

  4.1 Rubber Body Materials (Customized by Transported Medium)

  • EPDM: For cold/hot clean water, air, HVAC circulating water, anti-aging, weather resistance, working temperature -30℃~120℃
  • NR Natural Rubber: For general domestic water, low-cost, high elasticity
  • NBR Nitrile Rubber: For oil, fuel, oily wastewater, good oil resistance
  • PTFE Lined Rubber: For acid, alkali, corrosive chemical medium, anti-corrosion, non-stick medium
  • Hypalon/CR Chloroprene Rubber: For seawater, outdoor buried pipelines, anti-ozone, anti-salt spray

  4.2 Metal Component Materials

  • Flange: Q235 carbon steel hot-dip galvanized / SS304 / SS316 stainless steel
  • Limit tie rod & lugs: Grade 8.8 high-strength carbon steel galvanized / SS304 stainless steel for corrosive environment All rubber materials are vulcanized at high temperature, integrated molding without splicing seams, with excellent compression resistance, aging resistance and sealing performance.

  5. Complete Specification Range & Pressure Grade

  • Nominal Diameter: DN32 ~ DN1600, large size DN1800-DN3200 customizable
  • Nominal Pressure: PN6, PN10, PN16; American standard 150LB, Japanese standard 10K
  • Connection Standard: GB/T9113, DIN2501, ANSI B16.5, JIS10K
  • Product Length: Standard face-to-face dimension per national industry standards, customized short/long length available for special installation space Suitable for buried pipelines, overhead pipe racks, pump inlet/outlet sections and high-rise building vertical pipes.

  6. Wide Industrial Application Scope

  This safety-type rubber expansion joint is widely adopted in critical pipeline systems requiring anti-disengagement protection:
  1. Building HVAC & Water Supply: Chilled water, hot water circulation pipelines, fire fighting water supply pipes, high-rise water supply main pipes
  2. Municipal Engineering: Sewage treatment plants, reclaimed water pipelines, urban heating network
  3. Energy & Power: Cooling water system of power plant units, pump station outlet pipelines
  4. Petrochemical & Chemical: Oil delivery pipelines, weak acid/alkali medium conveying pipes
  5. Marine & Aquaculture: Seawater circulation pipelines, anti-corrosion fluid transmission
  6. Industrial Manufacturing: Compressor matching pipes, factory cooling circulation pipelines

  7. Installation & Maintenance Advantages

  1. Easy installation: Flange bolt connection, no welding required, greatly shorten construction period; small overall weight, convenient hoisting and alignment.
  2. No maintenance cost: All rubber and metal parts have long service life under rated working condition, no lubrication or regular replacement needed.
  3. Convenient inspection: The external limit tie rod assembly is exposed, allowing real-time visual check of stretching status without disassembling the pipeline.
  4. Good compatibility: Matches all common pipe materials including carbon steel, stainless steel, PVC, PE, cast iron without extra transition fittings.