Single Axial Bellows Expansion Joint

Single Axial Metal Bellows Expansion Joint, Flanged / Welded End, SS304 / SS316L

3“-20”
Single Axial Metal Bellows Expansion Joint is designed to absorb axial thermal displacement of straight pipelines. It consists of a single metal bellows with welded or flanged ends. Limit tie rods are optional for over-travel protection only, not to bear internal pressure thrust. Suitable for steam, hot water and chemical medium pipelines. Available in SS304, SS316L, compliant with GB/T12777 and EJMA standards.
Delivery
EXW
minimum order
10 pieces
Supply Ability
10pieces / Day
Country of Origin
CHINA
Stock Time
7Day
Quantity:
US $100.00 - US $799.00 / pieces
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1. Product Overview & Working Principle

The Single Axial Metal Bellows Expansion Joint is a non-restrained expansion device designed to absorb axial thermal expansion and contraction of straight pipeline sections. It consists of a single corrugated metal bellows (single-layer or multi-layer) welded or formed between two end connections — either welding ends (pipe stubs) or flanges. When the pipeline heats up and expands, the bellows is compressed along its axis; when the pipeline cools and contracts, the bellows extends. In this way, the bellows flexes elastically to take up the linear thermal movement of the pipe.

⚠️ Important: This type absorbs axial displacement only. It does not absorb lateral (transverse) offset or angular rotation. Because it is non-restrained, the internal pressure generates a large pressure thrust which must be fully borne by fixed anchors (main anchors), not by the compensator itself. Optional limit tie rods serve purely as over-travel / anti-collapse protection and must never be relied upon to carry the pressure thrust.

2. Technical Specifications

Below are the typical design parameters. Final values should be confirmed against the customer's working conditions and the applicable standard.

ParameterTypical Range / Options
Nominal Diameter (DN)DN32 – DN3000 (larger sizes on request)
Design PressurePN0.6 / PN1.0 / PN1.6 / PN2.5 MPa; Class series available
Design TemperatureSS304: -20℃ ~ 425℃; SS316L: -20℃ ~ 450℃
Bellows MaterialSS304 / SS316L / SS321, etc.
Layer ConfigurationSingle-layer or multi-layer
Axial CompensationTypically ±6 mm ~ ±50 mm, per wave count & layers
End ConnectionWelded (stub end) or Flanged
Optional AttachmentLimit tie rods (over-travel protection only)
Applicable StandardGB/T12777, JB/T8195.1; EJMA, ISO15348, ASME

3. Features, Applications & Selection Notes

Advantages: simple structure, low cost, compact footprint, easy installation — ideal for straight pipe runs. Limitations: limited compensation capacity, and demanding pipe-support design; fixed anchors plus guide supports must be provided to prevent lateral buckling of the bellows. It cannot absorb lateral or angular movements.

Typical applications: steam, hot water, compressed air, oil and chemical medium lines in thermal networks, power plants, petrochemical, metallurgy and HVAC systems — where displacement is purely axial and the pipe layout allows proper anchors and guides.

Selection / enquiry checklist (for your sales side): always confirm DN, design pressure, medium, temperature, required axial compensation, connection type, bellows material, whether limit tie rods are needed, and bellows layer number. Critically remind customers that fixed anchors must take the pressure thrust — many overseas clients mistakenly think the tie rods carry it, which is a common design failure point.