High-Performance Round Duct Expansion Joint
1. Premium circular round rubber expansion joint engineered for low-pressure gas pipelines and air blower networks.
2. Exceptional vibration isolation targeting 10Hz-100Hz frequency range from fans, blowers, and compressor equipment.
3. Multi-directional movement compensation: axial compression 50mm, extension 25mm, lateral shear, and angular rotation.
4. Artisan hand-wrapped bias-ply tire cord construction (45-54.7 degrees) far superior to mass-produced molded alternatives.
5. Chemical resistant inner liner options: Chlorobutyl standard, FKM/Viton for acid service up to 204°C, EPDM, Neoprene, Nitrile.
6. Massive diameter range DN100-DN4000 (4″-160″) with zero leakage integral full-face rubber flange design.
7. Vacuum service option with integrated solid steel wire helix prevents deformation and collapse.
8. Ideal for FD/ID fans, FGD systems, SCR units, cement plant ducts, steel mill extraction, and HVAC ventilation.
High-Performance Round Duct Expansion Joint
DEVEL Round Rubber Expansion Joint is a flexible fitting optimized for industrial low-pressure, high-volume air and gas handling networks.
Constructed from advanced multi-layer reinforced elastomers, these components function as structural dynamic balancers designed to mitigate thermal expansion stresses, absorb high-frequency mechanical vibrations from fans and blowers, and correct complex structural misalignments in large-scale ducting systems.
The precise circular geometry guarantees isotropic stress distribution — preventing localized stress concentrations under both positive pressure spikes and full vacuum conditions.
Engineered for forced draft and induced draft fan connections in power generation plants, high-temperature abrasive dust extraction piping in steel mills, flue gas desulfurization (FGD) systems, selective catalytic reduction (SCR) environmental protection units, cement plant air ducts, and industrial HVAC/ventilation networks.
Key Features at a Glance
- Exceptional Vibration Isolation Performance
The heavy-duty, high-density rubber matrix exploits elastomeric hysteresis to convert mechanical vibration waves from fans, blowers, and compressors into negligible thermal energy. Targets the critical 10Hz–100Hz frequency range, effectively isolating upstream rotating equipment from sensitive downstream inline instrumentation and ductwork structures. - Multi-Directional Movement Compensation
Utilizing optimized arch profile design ratios, this joint concurrently accommodates axial compression up to 50mm, axial extension up to 25mm, lateral shear deflection, and angular rotation — all within a compact face-to-face installation dimension while keeping spring rates exceptionally low for minimal reaction loads on connected equipment. - Bias-Ply Hand-Wrapped Construction
Each joint is manufactured using a hand-wrapped process, with multiple plies of high-tenacity synthetic tire cord fabric wrapped at 45° to 54.7° angles to optimize burst pressure rating and vacuum collapse resistance. - Chemical & Thermal Degradation Resistance
To counter aggressive acidic condensates such as sulfur oxides (SOx) and nitrogen oxides (NOx) present in flue gas streams, the inner liner can be formulated from Chlorobutyl or FKM (Viton) elastomer — ensuring polymer cross-linking remains intact without premature embrittlement or cracking even under prolonged acid exposure. - Zero Leakage Integral Full-Face Flange Design
The vulcanized integral full-face rubber flanges eliminate all critical leakage pathways entirely through elastic deformation of the joint body itself against the mating pipe flange — removing any requirement for auxiliary gaskets and ensuring a 100% airtight seal in sensitive negative-pressure dust extraction and environmental control setups. - Massive Diameter Range (DN100 – DN4000 / 4″ – 160″)
Available in an extraordinary size spectrum from small ventilation connectors at 100mm (4-inch) through massive power plant main duct joints at 4000mm (160-inch). Non-standard over-sized custom diameters available upon requisition for specialized project requirements beyond standard catalog sizes. - Wide Elastomer Material Portfolio
Standard Chlorobutyl liner for superior thermal rating and gas impermeability. Optional materials include EPDM for hot air service, FKM/Viton for extreme chemical/acid resistance up to 204°C, Neoprene for general-purpose use, Nitrile for oil-laden air streams, and Hypalon (CSM) for outdoor weathering environments. - Vacuum Service Capability with Wire Helix Option
For vacuum service applications requiring enhanced collapse resistance, an internal solid steel wire helix is integrated into the reinforcement core to prevent localized deformation or vacuum implosion while maintaining full flexibility for vibration isolation performance.
Materials & Construction Specification
Technical Parameters
Engineering Best Practices: Installation & Maintenance
- Torque Sequence Protocol: Mating bolts must be tightened using an incremental star (cross-diagonal) pattern. Tighten in 3 to 4 sequential stages to ensure even compression across the entire elastomeric face-to-face flange area. Excessive unilateral tightening will cause flange damage or structural seating leaks.
- Control Rods Integration: It is highly recommended to install limit/control rods on pipeline segments subjected to unexpected or uncontrolled thrust forces to prevent over-extension beyond the 25mm design threshold. Control rods protect both the flexible connector and adjacent equipment from displacement-induced failure.
- Weld Splatter Safeguards: If field welding operations occur adjacent to the flexible connector, the rubber body must be completely insulated using certified high-temperature welding blankets. Direct slag contact will compromise the cross-linked outer cover rubber matrix and void warranty coverage.
Primary Industrial Sectors
Steel Mills Dust Extraction
Flue Gas Desulfurization (FGD)
Selective Catalytic Reduction (SCR)
Cement Plant Air Ducts
Industrial HVAC Ventilation
Chemical Vapor Processing Lines
Smelting Plant Exhaust
Product Tags
Circular Duct Connector
Rubber Expansion Joint
Vibration Isolation
FD ID Fan Connector
FGD System
Chlorobutyl Lining
FKM Viton Liner
EPDM Rubber
Hand Wrapped Construction
Full Face Flange
Zero Leakage
Cement Plant Duct
Dust Extraction Piping
Request a Custom Quote for Your Project
Factory-direct pricing available. DEVEL engineering team ready to assist with material selection, sizing calculations, and installation guidance.





