DN150 Hand-Built 5-Arch Oil-Resistant NBR Rubber Expansion Joint with 650mm Length and Carbon Steel Flanges

This heavy-duty DN150 (6-inch) hand-built rubber expansion joint is structurally engineered for large-scale hydraulic oil distribution networks, high-capacity servo pump stations, and heavy machinery testing foundations experiencing structural settlement or severe piping vibration. Featuring an extended 650mm face-to-face layout and an advanced 5-arch geometry, this multi-arch expansion bellow delivers massive multi-axis movement capability. It actively dampens continuous hydraulic fluid pulsations and structural shifts under a 1Mpa (10 bar) working pressure rating. Designed to operate flawlessly with synthetic and mineral hydraulic fluids at a stable 55°C temperature window, this rubber flexible joint serves as the critical elastomeric buffer to prevent piping stress cracks on rigid headers.

The structural matrix of the rubber bellow is meticulously hand-built, embedding multiple layers of high-tensile synthetic fiber cords at cross-plied stress-mitigating angles within a premium Nitrile (NBR) compound. The specialized internal NBR liner provides total immunity to oil-induced swelling, blistering, and structural degradation, ensuring long-term structural integrity under constant laminar or turbulent petroleum-based fluid streams. For external reinforcement, high-visibility alignment bands isolate individual arches to manage geometric volume changes under peak system pressure spikes.

Departing from standard full-face configurations, this high-performance soft-connection unit utilizes a precision ring face sealing (reduced face) profile. A rigid internal steel O-ring core is vulcanized directly into the narrow sealing rim, establishing a positive mechanical lock into the flange groove to prevent rubber bead pull-out or creeping under 1Mpa cycles. Outfitted with heavy-duty carbon steel swivel flanges, the split-ring backing plates rotate a full 360 degrees, allowing mechanical installation teams to index bolt circles across the 650mm span effortlessly without introducing harmful torsional pre-stress to the elastomer core.

While this standard configuration addresses industrial pump configurations, our manufacturing facility provides comprehensive custom-to-drawing fabrication. We tailor the elastomeric liner thicknesses, unique offset dimensions, and non-standard flange standards directly from your CAD prints. Backed by rigorous premium-grade B2B quality control protocols, we maintain reactive manufacturing pipelines to guarantee exceptionally short lead times, eliminating delivery delays and ensuring minimal downtime for critical system retrofits.

Key Features 

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  • High-Purity NBR Interior Liner: Premium Nitrile matrix provides superior resistance to petroleum-based fluids and hydraulic oils, preventing polymer softening at 55°C.
  • Multi-Arch High-Displacement Architecture: Advanced 5-arch configuration maximizes axial compression, elongation, and lateral shearing capacity across ground settlement boundaries.
  • Precision Ring Face Sealing Profile: Small-rim sealing design eliminates the need for supplementary gaskets while ensuring drop-tight performance under 1Mpa continuous pressures.
  • Embedded Anti-Pullout O-Ring Core: Internal rigid steel ring embedded in the sealing lip creates a positive mechanical shoulder to eliminate bead unseating during dynamic shifts.
  • 360° Free Rotating Swivel Flanges: Heavy-duty carbon steel backing rings spin freely to eliminate installation pre-stress and simplify misaligned bolt-hole matching.
  • High-Tensile Fabric Reinforcement Infrastructure: Multi-ply high-tensile synthetic fiber cord skeleton ensures uniform pressure distribution and prevents localized ballooning or bursting.

Applications & Equipment 

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  • Heavy Duty Hydraulic Power Units (HPUs): Elastic soft connections coupling high-capacity hydraulic pump discharge headers to central valve manifolds.
  • Structural Simulation Test Rigs: Flexible long-span interfaces isolating high-frequency hydraulic actuator feedback pulsations from buried fluid supply lines.
  • Industrial Oil Filtration Circuits: Vacuum and pressure resistant NBR rubber bellow modules connecting primary recirculation pumps to chemical oil purification skids.
  • Lubrication System Return Headers: Non-standard reduction links absorbing thermal expansion and settling on large-scale turbine or compressor oil lubrication loops.