Small-Bore DN15 Twin-Sphere NBR Rubber Expansion Joint with Full Rubber Encapsulated Flanges for Ship Fuel Overflow Lines
Product Overview
This custom DN15 small-bore rubber expansion joint is engineered as a direct 1:1 dimension match and performance interchange for Trelleborg marine bellows operating in JIS 5K piping networks. Purpose-built for shipyard new-builds and vessel refits, this twin-sphere rubber flexible joint is configured specifically for shipboard fuel oil overflow lines where installation space is highly restricted.
The core expansion bellow utilizes high-nitrile NBR (Nitrile Butadiene Rubber) to provide permanent resistance to hydrocarbon swells, fuel oils, and diesel permeation. To eliminate the manufacturing defects common in small-diameter molded parts, this unit is hand-wrapped to a specified 250mm face-to-face length. The twin-sphere geometry provides extended multi-axial deflection in tight layouts. Instead of standard turn-up sealing faces, a specialized full-rubber encapsulation process is applied. The NBR compound completely covers the sealing face and outer perimeters of the galvanized carbon steel flanges through high-pressure vulcanization. This seamless elastomer shield prevents galvanic corrosion from salt spray and blocks external fuel mist degradation. Production is executed according to exact CAD sketches to solve precise marine soft-connection issues with short lead times.
Key Features
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- 1:1 Trelleborg Small-Bore Fit: Engineered to exact structural profiles to serve as a direct plug-and-play replacement for equivalent Trelleborg small-diameter series.
- High-Nitrile NBR Core: Formulated for zero-leakage oil handling, offering excellent resistance to fuel oil swelling, petroleum hydrocarbons, and aromatic solvents.
- Full Rubber Encapsulated Flanges: Complete NBR encapsulation on the galvanized carbon steel flange faces and outer rims eliminates metal-to-salt-air exposure and boundary leaks.
- Twin-Sphere Small-Diameter Architecture: Hand-wrapped double-sphere configuration maximizes axial compression and lateral offset compensation within a compact 15mm nominal bore.
- JIS 5K Marine Standard Drilling: Flange bolt holes are precisely aligned to Japanese shipbuilding specifications, ensuring drop-in compatibility during urgent dry-dock overhauls.
Applications
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- Shipyard Fuel Oil Overflow Lines: Flexible connection on low-pressure petroleum oil transfer and overflow piping networks.
- Marine Generator Fuel Skids: Isolation of high-frequency mechanical vibration between diesel auxiliary engines and rigid steel feed pipes.
- Vessel Bilge & Oil-Water Separators: Corrosion-resistant soft links handling mixed oily wastewater in congested machinery spaces.
FAQ
Q: Why is a hand-wrapped DN15 twin-sphere NBR rubber compensator with encapsulated flanges required for marine fuel overflow lines?
A: Small-bore fuel lines in ship engine rooms present severe engineering challenges due to narrow spaces, constant vibration, and strict fire/leakage regulations. Our specialized rubber expansion joint meets these parameters through:
- Elimination of Small-Bore Molding Stress: Standard mass-produced molded bellows in DN15 sizes often suffer from uneven wall thickness and fabric displacement in the tight arch profile. Precise hand-wrapped processes allow layer-by-layer reinforcement positioning, ensuring structural integrity under continuous engine harmonics.
- Hydrocarbon-Proof Sealing Face: Fuel oil degrades standard EPDM or low-grade rubber rapidly, leading to softening and blowout failures. By utilizing premium NBR combined with full-face encapsulation, the internal fluid and external oil mist only contact oil-resistant elastomer, protecting the carbon steel flanges from fuel-induced degradation.
- 1:1 Interchange According to CAD Blueprints: Shipyards cannot modify rigid steel piping grids just to fit standard catalog joints during a refit. If your drawings require an exact 250mm face-to-face distance and JIS 5K flange profiles to replace worn Trelleborg parts, we provide exact custom-to-drawing production to match your files.
- Short Manufacturing Cycles for Dry-Dock Readiness: Marine logistics delays directly increase port penalties for shipyards. Factory manufacturing enforces strict industrial quality control and pressure testing, while deploying responsive production lines to guarantee rapid delivery, getting your fuel system certified without overseas waiting times.
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JIS 5K DN15 Custom 250mm Marine NBR Rubber Compensator - Twin Sphere Flexible Joint with Rubber Encapsulated Flanges | Alternative to Trelleborg
JIS 5K DN15 small-bore twin-sphere marine rubber expansion joint for fuel oil overflow pipelines. Full rubber encapsulated flanges. Custom 250mm length.
Product SKU: WCR-DN15-NBR-5K-CS-250MM
Product Brand: SONGJIANGFLEX
Product In-Stock: InStock
