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1. Product Overview
Rubber expansion joints (flexible connectors) are vibration-absorbing, pressure-compensating connectors for piping systems, designed to absorb movement, reduce noise, and compensate for misalignment. They consist of elastomeric bellows with internal reinforcement and flange/threaded end connections.
✔ Vibration Damping – Reduces pipe vibration by up to 95%
✔ Movement Absorption – Compensates for axial, lateral & angular movement
✔ Noise Reduction – Lowers water hammer & system noise
✔ Corrosion Resistance – Immune to electrolytic/galvanic corrosion
✔ Easy Installation – No special tools required
2. Construction Types
|
Type |
Movement Capability |
Max Pressure |
Primary Use |
|
Single Sphere |
Axial: ±15mm Lateral: ±10mm |
PN16 |
General water systems |
|
Double Sphere |
Axial: ±25mm Lateral: ±20mm |
PN10 |
High-movement applications |
|
Tied Single Sphere |
Angular: ±15° |
PN25 |
Pressure surge protection |
|
Flanged vs. Threaded |
– |
PN10-PN25 |
Small vs. large diameter systems |
Nylon Cord – Standard pressure resistance
Steel Wire – High-pressure applications (PN25+)
Kevlar® – Extreme burst pressure resistance
3. Elastomer Options
|
Material |
Temperature Range |
Chemical Resistance |
Common Applications |
|
EPDM |
-30°C to +120°C |
Acids, alkalis, ozone, steam |
Hot water, HVAC, chemicals |
|
NBR |
-20°C to +100°C |
Oils, fuels, hydrocarbons |
Petroleum, diesel systems |
|
Neoprene |
-40°C to +110°C |
Weather, seawater |
Marine, outdoor installations |
|
Silicone |
-60°C to +230°C |
High-temperature air/steam |
Food, pharma, exhaust systems |
|
Hypalon® |
-40°C to +150°C |
Strong oxidizers, chlorinated water |
Water treatment, bleach lines |
4. Technical Specifications
|
Parameter |
Specification Range |
|
Size Range |
DN15–DN3000 (½"–120") |
|
Pressure Rating |
PN6–PN40 (ANSI 150–300) |
|
Burst Pressure |
3–5× working pressure |
|
Movement Capacity |
Axial: ±5–30mm Lateral: ±5–25mm Angular: ±5–15° |
|
Vacuum Rating |
Full vacuum (with wire reinforcement) |
5. Industry Applications
✔ HVAC Systems – Absorb thermal expansion in chillers
✔ Water Treatment – Compensate for pump vibrations
✔ Marine Engineering – Accommodate hull/pipeline movement
✔ Power Plants – Steam line vibration isolation
✔ Chemical Processing – Corrosion-resistant acid lines
6. Selection Guide
|
Application |
Recommended Type |
Elastomer |
Reinforcement |
|
Chilled Water |
Single Sphere, Flanged |
EPDM |
Nylon |
|
Fuel Oil Transfer |
Double Sphere, Threaded |
NBR |
Steel Wire |
|
Seawater Cooling |
Tied Single Sphere |
Neoprene |
Kevlar® |
|
Chemical Dosing |
Flanged, Lined |
Hypalon® |
PTFE Liner |
7. Installation Guidelines
Pre-Stretch – Extend 50% of max axial movement during installation
Alignment – Avoid permanent torsion (>5° twist)
Anchoring – Use control rods for pressure thrust applications
Avoid – Proximity to heat sources (>10cm from hot pipes)
8. Standards Compliance
ISO 9001 – Quality management
EN 14931 – European rubber joint standard
FDA 21 CFR – Food-grade compliance (silicone/EPDM)
DVGW – German water industry approval
UL Listed – Fire-resistant models
9. Why Choose Our Rubber Expansion Joints?
✅ Full Movement Compensation – Tested to EJMA standards
✅ Custom Fabrication – Odd sizes, special flanges, linings
✅ Extended Warranties – Up to 10 years for standard models
✅ Technical Support – Movement calculation services
Request our Vibration Isolation Guide or CAD Models!
It absorbs vibration, compensates for thermal expansion and angular movement, seals fluid, and protects pipelines from stress and damage.
Common materials include EPDM, NBR, NR and silicone rubber, suitable for different media, temperatures and working environments.
Yes, our rubber bellow swivels are designed for various pressure ratings and can be customized for medium and high-pressure systems.
Yes, the swivel structure allows free rotation and deflection, ensuring long service life even under frequent dynamic working conditions.





Address
20 Xingyuan South Street, Zaoqiang County, Hengshui City, Hebei Province, China