Zhengda Valve
One-Stop Supplier for Rubber Joints, Bellows, and Waterproof Casings
Rubber Reducer Expansion Joint
The Rubber Reducer, also known as Rubber Reducing Joint, Rubber Eccentric Reducer, or Flexible Reducer Connector, is specially designed to connect pipelines of different diameters. It helps compensate for displacement, reduce vibration, and eliminate installation mismatches. Commonly used in HVAC systems, water treatment plants, and industrial pipelines, it supports both concentric and eccentric structures based on flow needs.
Key Features
• Size Transition – Connects pipelines with different diameters seamlessly.
•Shock & Noise Absorption – Reduces mechanical stress and noise during operation.
•Eccentric & Concentric Options – Available for various flow direction needs.
•Flexible Installation – Easy to align and install in limited spaces.
•Corrosion Resistance – Suitable for water, oil, and weak acid/alkaline media.
•Also Known As – Flexible Reducer, Rubber Eccentric Coupling, Concentric Rubber Joint.
Technical Specifications
| Nominal Diameter (DN) | Inch | Length (L) mm | Flange Thickness (b) mm | Bolt Qty (n) | Bolt Hole Dia. mm | Bolt Circle Dia. (D1) mm | Axial Extension mm | Lateral Displacement mm | Angular Deflection (°) |
|---|
| DN32×25 | 1¼”×1″ | 95 | 16 | 4 | 18 | 100 | 6 | 9 | 9 |
| DN40×32 | 1½”×1¼” | 95 | 18 | 4 | 18 | 110 | 6 | 10 | 9 |
| DN50×40 | 2″×1½” | 105 | 18 | 4 | 18 | 125 | 7 | 10 | 10 |
| DN65×50 | 2½”×2″ | 115 | 20 | 4 | 18 | 145 | 7 | 13 | 11 |
| DN80×65 | 3″×2½” | 135 | 20 | 4 | 18 | 160 | 8 | 15 | 12 |
| DN100×80 | 4″×3″ | 150 | 22 | 8 | 18 | 180 | 10 | 19 | 13 |
| DN125×100 | 5″×4″ | 165 | 24 | 8 | 18 | 210 | 12 | 19 | 13 |
| DN150×125 | 6″×5″ | 180 | 24 | 8 | 23 | 240 | 12 | 20 | 14 |
| DN200×150 | 8″×6″ | 210 | 24 | 8 | 23 | 295 | 16 | 22 | 14 |
| DN250×200 | 10″×8″ | 230 | 26 | 12 | 23 | 350 | 16 | 25 | 14 |
| DN300×250 | 12″×10″ | 245 | 28 | 12 | 23 | 400 | 16 |
| Project | Unit | CRJ-1 | CRJ-2 | CRJ-3 |
|---|---|---|---|---|
| Model | – | CRJ-1 | CRJ-2 | CRJ-3 |
| Working Pressure | MPa (kgf/cm²) | 1.0 (10) | 1.6 (16) | 2.5 (25) |
| Burst Pressure | MPa (kgf/cm²) | 2.0 (20) | 3.0 (30) | 4.5 (45) |
| Vacuum Resistance | KPa (mmHg) | 53.3 (400) | 86.7 (650) | 100 (750) |
| Operating Temperature | °C | -15 ~ 115°C (Special: -30 ~ 250°C) | -15 ~ 115°C (Special: -30 ~ 250°C) | -15 ~ 115°C (Special: -30 ~ 250°C) |
| Applicable Media | – | Air, Compressed Air, Water, Seawater, Hot Water, Oil, Acid, Alkali, etc. | Air, Compressed Air, Water, Seawater, Hot Water, Oil, Acid, Alkali, etc. | Air, Compressed Air, Water, Seawater, Hot Water, Oil, Acid, Alkali, etc. |
| Material | Temperature Range (°C) | Oil Resistance | Acid & Alkali Resistance | Elasticity | Abrasion Resistance | Typical Applications |
|---|
| EPDM | -40 ~ 120 | Poor | Excellent | Excellent | Medium | Water, Steam, Air |
| NR (Natural Rubber) | -30 ~ 80 | Poor | Medium | Excellent | Excellent | Industrial Water, Air |
| NBR | -20 ~ 100 | Excellent | Medium | Good | Good | Oil, Lubrication Systems |
| Neoprene | -35 ~ 100 | Good | Good | Medium | Good | Seawater, Mild Chemicals |
| Silicone | -60 ~ 200 | Poor | Poor | Good | Low | Food Grade, Medical |
| FKM (Viton) | -20 ~ 250 | Excellent | Excellent | Medium | Excellent | Chemical, High Temp Oil |
| Butyl (IIR) | -40 ~ 120 | Poor | Good | Excellent | Medium | Gas, Acidic Gases |
1.Inspection Before Installation
•Check whether the rubber joint is damaged, aged, or defective.
•Confirm the model, pressure rating, and flange size match the system requirements.
2.Installation Environment
•Avoid installation under direct sunlight, ozone, or in environments with high temperature or strong corrosive chemicals.
•If outdoor installation is necessary, use UV-protective shields or covers.
3.Installation Instructions
•Align the rubber joint with the center of the pipe flanges. Avoid pulling or twisting during installation.
•Tighten bolts crosswise and evenly to avoid uneven force or deformation.
•Use proper washers and gaskets.
4.Precautions
•Ensure the pipeline is properly fixed; rubber joints are not designed to bear the full weight.
•Do not over-extend, over-compress, or apply excessive torsion to the joint.
•Allow for movement as specified (axial, lateral, angular) within rated limits.
•Install limit rods or anti-pull devices if the pipe system lacks sufficient fixation.
5.Working Pressure & Temperature
•Observe the rated pressure and temperature range during operation.
•Standard range: -15°C to +115°C (or as specified).
6.Routine Inspection & Maintenance
•Inspect every 6–12 months for signs of aging, damage, or leakage.
•Replace if any abnormalities are found.
1. Inspection Before Installation
•Check whether the rubber joint is damaged, aged, or defective.
•Confirm the model, pressure rating, and flange size match the system requirements.
2.Installation Environment
•Avoid installation under direct sunlight, ozone, or in environments with high temperature or strong corrosive chemicals.
•If outdoor installation is necessary, use UV-protective shields or covers.
3.Installation Instructions
•Align the rubber joint with the center of the pipe flanges. Avoid pulling or twisting during installation.
•Tighten bolts crosswise and evenly to avoid uneven force or deformation.
•Use proper washers and gaskets.
4.Precautions
•Ensure the pipeline is properly fixed; rubber joints are not designed to bear the full weight.
•Do not over-extend, over-compress, or apply excessive torsion to the joint.
•Allow for movement as specified (axial, lateral, angular) within rated limits.
•Install limit rods or anti-pull devices if the pipe system lacks sufficient fixation.
5.Working Pressure & Temperature
•Observe the rated pressure and temperature range during operation.
•Standard range: -15°C to +115°C (or as specified).
6.Routine Inspection & Maintenance
•Inspect every 6–12 months for signs of aging, damage, or leakage.
•Replace if any abnormalities are found.
What kind of documents are included with the shipment?
We provide a full set of export documents, including packing list, commercial invoice, product test report, and material certificate. Custom clearance documents are also available upon request.
What sizes and materials are available for rubber expansion joints?
Our rubber joints are available in sizes from DN32 to DN1200, and materials include EPDM, NBR, Neoprene, PTFE-lined rubber, and food-grade silicone. Custom materials are available for specific industries.
Can you produce customized rubber joints according to our drawing?
Yes. We support OEM and ODM services. Just send us your drawing or specifications, and our technical team will provide a matching solution with fast production.
Why Choose Zhengda Valve & Pipeline Co., Ltd.?
•18+ Years of Experience: Trusted manufacturer of rubber expansion joints and pipeline solutions since 2005.
•Certified Quality: ISO certified factory with strict quality control and full material traceability.
•Custom Solutions: OEM & ODM supported with fast turnaround and technical support.
•Competitive Pricing: Factory-direct pricing ensures cost-effective solutions for global buyers.
•Reliable Service: Fast response, on-time delivery, and long-term partnership mindset.
Let Us Help With Your Pipeline Needs
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Let Us Help With Your Pipeline Needs
We respond quickly to inquiries and provide expert support on rubber joints, metal hoses, and customized solutions.