FLEXIBLE PIPE CONNECTIONS
Rubber Expansion Joint for Flexible Pipe Connections
LEEVOA PIPE supplies rubber expansion joints designed to accommodate pipeline movement, reduce vibration and noise, and provide flexible connections between piping and connected equipment. Available configurations include single sphere, double sphere, threaded, PTFE-lined, large-diameter and special-purpose designs.
What Is a Rubber Expansion Joint?
A rubber expansion joint is a flexible piping component installed between pipe sections or connected equipment. Its reinforced elastomer body can accommodate limited axial, lateral and angular movement while helping isolate vibration and reduce structure-borne noise.
Rubber expansion joints are commonly installed where piping movement, equipment vibration, thermal expansion or minor alignment variation needs to be accommodated without creating a fully rigid connection.
Rubber Expansion Joint Configurations
Single Sphere Rubber Expansion Joint
The single sphere design uses one reinforced rubber arch between two flange connections. It provides a compact flexible connection for absorbing pipeline movement and reducing vibration and noise.
Double Sphere Rubber Expansion Joint
The double sphere design uses two flexible arches and provides greater movement capacity than a comparable single sphere configuration. It is available with different flange, rubber and control-unit options.
Union Screwed Rubber Expansion Joint
Threaded rubber expansion joints provide a compact alternative for smaller-diameter piping systems where a threaded union connection is preferred instead of flanged ends.
PTFE-Lined Rubber Expansion Joint
PTFE-lined rubber expansion joints add an internal PTFE lining for applications involving media that require greater chemical resistance than a conventional exposed rubber surface.
Use only for compatible media after material compatibility is confirmed.
Full-Face / Large-Diameter Rubber Expansion Joint
Full-face sealed and large-diameter configurations are available for engineering pipelines requiring larger nominal diameters, alternative flange designs or project-specific dimensions.
Hand-Made / Custom Rubber Expansion Joint
Hand-made rubber expansion joints can be produced for project-specific face-to-face dimensions, flange drilling and rubber material requirements.
Elbow Rubber Expansion Joint
Elbow-type rubber expansion joints combine directional piping geometry with flexible movement and vibration isolation where a straight joint configuration is not suitable.
Food-Grade Rubber Expansion Joint
White sanitary rubber expansion joints are available for selected food and beverage piping applications using food-grade silicone rubber.
Rubber Expansion Joint Specifications
| Specification | Available Options |
|---|---|
| Product | Rubber Expansion Joint |
| Main Configurations | Single sphere, double sphere, threaded union, PTFE-lined, full-face, hand-made, elbow and sanitary types |
| Rubber Materials | EPDM, NBR, NR, CR / Neoprene; other compounds available by configuration |
| Reinforcement | Nylon cord fabric with steel reinforcement, depending on design |
| Flange Materials | Carbon steel, galvanized carbon steel, ductile iron, SS304, SS316 |
| Product-Family Size Capability | DN15–DN4000 across different configurations; actual range depends on joint type |
| Working Pressure | Configuration dependent; common PN10 / PN16 / PN25 options, with other ratings available for selected designs |
| Flange Standards | DIN / EN, ANSI / ASME, JIS and project-specific flange drilling |
| Movement | Axial, lateral and angular movement depending on design |
| Connection | Flanged or threaded union |
| PTFE Lining | Available |
| Control / Limit Units | Available for selected configurations |
| Custom Face-to-Face Length | Available for selected designs |
| OEM / ODM | Available |
Size, movement and pressure capability are configuration dependent. Final dimensions and technical requirements should be confirmed for the selected joint design.
Rubber Expansion Joint Construction
A typical flanged rubber expansion joint consists of inner and outer elastomer layers, reinforced cord fabric, steel reinforcement and metal flanges. The reinforced rubber body provides flexibility while the flange assembly connects the joint to the piping system.
- Outer Rubber Layer
- Reinforcing Cord Fabric
- Steel Reinforcement
- Inner Rubber Layer
- Rubber Arch / Sphere
- Flange
Rubber Material Options
EPDM
Commonly selected for water, hot water, air and other compatible services where EPDM resistance characteristics match the operating medium and temperature.
NBR
Commonly selected where oil, fuel or hydrocarbon resistance is required.
CR / Neoprene
Available for applications requiring an alternative balance of weather, oil and general environmental resistance.
NR / Natural Rubber
Available for selected general-service configurations where natural rubber is suitable for the medium and operating conditions.
FKM and Other Compounds
Available for selected special configurations and should be specified according to the actual medium and temperature.
Operating temperature depends on elastomer compound, medium, pressure and joint construction.
Flange Materials and Standards
Flange Materials
- Carbon Steel
- Galvanized Carbon Steel
- Ductile Iron
- Stainless Steel 304
- Stainless Steel 316
Flange Standards
DIN / EN, ANSI / ASME, JIS and project-specific flange drilling are available depending on the selected configuration.
What Problems Does a Rubber Expansion Joint Help Manage?
Pipeline Movement
The flexible rubber body can accommodate axial, lateral and angular movement within the movement capability of the selected joint.
Vibration Isolation
Rubber expansion joints can reduce vibration transfer between pumps, mechanical equipment and connected piping.
Noise Reduction
The elastomer body helps interrupt the direct transmission of structure-borne vibration and associated pipeline noise.
Thermal Expansion and Contraction
Rubber joints can help accommodate movement caused by temperature changes where the selected joint and pipeline design provide the required movement capacity.
Minor Alignment Variation
Flexible joints can tolerate limited alignment variation, but they should not be used to correct major pipeline misalignment.
Single Sphere vs Double Sphere Rubber Expansion Joint
| Feature | Single Sphere | Double Sphere |
|---|---|---|
| Rubber Arches | One | Two |
| Face-to-Face Length | Generally more compact | Generally longer |
| Movement Capacity | Standard flexible movement | Greater movement capability |
| Typical Use | General piping, pumps, HVAC, water systems | Applications requiring greater movement |
| Available Control Units | Yes, depending on configuration | Yes, depending on configuration |
When Are Limit Rods or Control Units Used?
Limit rods or control units are available for selected rubber expansion joint configurations to restrict excessive extension or movement and to support the joint in piping systems where pressure thrust or anchoring conditions require additional control.
Rubber Expansion Joint Applications
Water & Wastewater Systems
Flexible connections in water supply, treatment, drainage and wastewater piping systems.
Pump Connections
Vibration-isolating flexible connections around pumps and associated piping equipment.
HVAC & Building Services
Flexible movement and vibration control in cooling, heating, refrigeration and mechanical piping systems.
Industrial Piping
Movement compensation and flexible connections in compatible industrial fluid systems.
Marine & Seawater Systems
Selected rubber materials and flange configurations can be used in compatible seawater and marine piping services.
How to Select a Rubber Expansion Joint
1. Confirm Nominal Pipe Size
Provide the required DN or NPS.
2. Confirm the Working Medium
Specify water, seawater, air, oil, gas, chemical solution or other medium so an appropriate elastomer can be selected.
3. Provide Working Temperature
Operating temperature is essential for rubber compound selection.
4. Confirm Working Pressure
Provide normal operating pressure and any relevant test or surge pressure requirement.
5. Specify Required Movement
If known, provide axial compression, axial extension, lateral movement and angular movement requirements.
6. Confirm Flange Standard
Specify DIN / EN, ANSI / ASME, JIS or the required project flange drilling.
7. Confirm Flange Material
Carbon steel, galvanized carbon steel, ductile iron, SS304 and SS316 options are available depending on configuration.
8. Identify Installation Conditions
Indicate whether control rods, special face-to-face dimensions, PTFE lining or other project-specific features are required.
Typical Single Sphere Face-to-Face Dimensions
| DN | Face-to-Face Length |
|---|---|
| 32 | 95 mm |
| 40 | 95 mm |
| 50 | 105 mm |
| 65 | 115 mm |
| 80 | 135 mm |
| 100 | 150 mm |
| 125 | 165 mm |
| 150 | 180 mm |
| 200 | 210 mm |
| 250 | 230 mm |
| 300 | 245 mm |
| 350 | 255 mm |
| 400 | 255 mm |
| 450 | 255 mm |
| 500 | 255 mm |
| 600 | 260 mm |
Dimensions vary by configuration, flange standard and project requirement. Confirm the final approved drawing before ordering.
Rubber Expansion Joint FAQ
What is a rubber expansion joint used for?
A rubber expansion joint provides a flexible connection that can accommodate limited pipeline movement while helping reduce vibration and noise between connected pipe sections or equipment.
What is the difference between a single sphere and double sphere expansion joint?
A single sphere joint uses one flexible arch, while a double sphere design uses two. Double sphere configurations generally provide greater movement capacity but also have a longer face-to-face dimension.
What rubber materials are available?
EPDM, NBR, natural rubber and CR / Neoprene are commonly available, with additional materials for selected applications.
What flange materials are available?
Carbon steel, galvanized carbon steel, ductile iron, SS304 and SS316 flange options are available depending on the selected configuration.
What flange standards can be supplied?
DIN / EN, ANSI / ASME and JIS flange drilling are commonly available, with project-specific standards possible for selected products.
What size rubber expansion joints are available?
The overall product family includes configurations from small threaded joints through very large engineered flanged joints. The applicable DN range depends on the selected joint type rather than one universal size range.
Can PTFE-lined expansion joints be supplied?
Yes. PTFE-lined configurations are available for applications requiring an internal PTFE barrier, subject to medium, pressure and temperature compatibility.
Can custom face-to-face lengths be supplied?
Yes. Selected hand-made and project-specific configurations can be produced with customized installation lengths.
Need a Rubber Expansion Joint for Your Piping System?
Send us the DN, working medium, temperature, pressure, flange standard and required movement information. We can review the operating conditions and help identify a suitable rubber expansion joint configuration before quotation.