Product Overview
The flanged bellows expansion joint (compensator) is a flexible pipe connection element designed to absorb dimensional changes in piping systems caused by thermal expansion, contraction, vibration, and mechanical movement. It consists of one or more convoluted stainless steel bellows assembled between two matching flanges, with adjustable tie rods that control the maximum extension and compression travel while allowing controlled flexibility.
The bellows are hydroformed from high-quality austenitic stainless steel to ensure uniform wall thickness, excellent fatigue life, and pressure-tight performance. The tie rods not only protect the bellows from over-extension during pressure testing, transportation, and installation, but also transmit the main anchoring loads, reducing stress on adjacent equipment such as pumps and valves. This product is widely used in HVAC, water supply and drainage, fire protection, chemical processing, and power generation piping systems.
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Key Features
Multi-Directional Compensation — Absorbs axial, lateral (shear), and angular movements in a single unit, accommodating thermal displacement of long pipeline runs and equipment misalignment.
Tie-Rod Protection — Four adjustable tie rods with nuts limit bellows over-travel, absorb pressure thrust, and enable safe pre-setting (pre-stretch/compression) during installation.
Superior Fatigue Life — Hydraulically formed AISI 304/316L bellows with multi-ply construction deliver thousands of movement cycles with consistent elastic performance.
Reliable Sealing — Integral bellows construction provides a fully leak-tight metal seal — no gaskets in the flow path — suitable for zero-leakage requirements.
Easy Flanged Installation — Standard PN10/PN16 flanges (ISO 7005-1 / EN 1092-1, DIN 2576, or ANSI B16.5 on request) allow quick bolting between pipe sections or equipment.
Vibration & Noise Reduction — Effectively isolates mechanical vibration and pump pulsation noise, protecting downstream equipment and extending system service life.
| Item | Specification |
|---|---|
| Product Name | Flanged Bellows Expansion Joint (Tie-Rod Type Compensator) |
| Model Series | JDZ / JTW Series (e.g., JDZ-100×16-F); custom markings available |
| Nominal Diameter (DN) | DN50 – DN1200 (2" – 48") |
| Pressure Rating | PN6 / PN10 / PN16 / PN25 (Class 150 / Class 300 on request) |
| Axial Compensation | ±10 mm to ±80 mm depending on size and number of convolutions (customizable) |
| Lateral Compensation | Up to ±15 mm (varies with DN and bellows length) |
| Angular Compensation | Up to ±5° |
| Bellows Material | AISI 304 / 321 / 316L stainless steel, multi-ply hydroformed |
| Flange Material | Carbon steel (Q235B / 20#), stainless steel 304/316 optional |
| Tie Rods | Carbon steel with galvanized finish; nuts adjustable for pre-setting |
| Connection Type | Fixed flange connection (weld neck / plate flange options available) |
| Working Temperature | -20 °C to +250 °C (up to +450 °C with high-temperature design) |
| Applicable Media | Hot & cold water, steam, HVAC chilled water, oil, air, gas, weak acids and alkalis (per bellows material selection) |
| Design Standard | EJMA / GB/T 12777 / GB/T 26007 |
| Flange Standard | EN 1092-1 (PN10/16), DIN 2576, ANSI B16.5 Class 150 optional |
| Testing | 1.5 × rated pressure hydrostatic test; 100% leak & dimensional inspection |
| Service Life | ≥ 1,000 – 5,000 movement cycles (design-dependent); service life ≥ 10 years under normal conditions |
Customization: Non-standard sizes, special flange drilling, multi-ply reinforced bellows, protective sleeves (liners), and external covers are available on request. Please provide pipe diameter, working pressure, media, temperature, and expected movement when ordering.
Typical Applications
HVAC & Chilled Water Systems: Absorbs thermal expansion in chilled / hot water risers and headers of central air-conditioning plants, protecting chillers and pumps.
Water Supply & Drainage: Compensation for ground settlement and thermal movement in municipal and building water pipelines.
Fire Protection Pipelines: Flexible connection at pump rooms and risers subject to seismic or building movement.
Chemical & Petrochemical: Corrosion-resistant 316L bellows options for process lines carrying steam, condensate, and mild chemical media.
Power Generation: Turbine condensate lines, boiler feed lines, and auxiliary cooling circuits.
Compressed Air & Gas: Vibration isolation at compressor outlets and gas transmission stations.
Selection & Installation Guidelines
Determine the total expected movement (axial ± lateral ± angular) of the pipeline before selecting the compensation capacity.
Fixed points (main anchors) and guides must be arranged per EJMA recommendations; tie rods shall not be used as pipe alignment tools.
During installation, pre-set the joint according to the ambient installation temperature to maximize available compensation travel.
Avoid torsion during installation; do not rotate the bellows with pipe wrenches.