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Metal Bellows Expansion Joints

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Metal Bellows Expansion Joints

Metal Bellows Expansion Joints

Product Parameters

Product Name Metal Bellows Expansion Joints
Item No. 1-3
Supply Type Sell
Category Industrial Supplies Hardware > Mechanical Parts > Metal Bellows

Detailed Product Description

1. Definition:

1.1 Bellows:
Bellows is the most important flexible element of an expansion joint / expansion compensator. It consists of one or more convolutions with one to five plies according to the design requirements.

The most recommended international design standards for quality expansion joint and manufacturing are EJMA (Expansion Joint Manufacturers Association) and ASME (American Society of Mechanical Engineers) Section Ⅷ.

1.2 Convolution:
The smallest flexible unit of a bellows. The total movement capacity of a bellows is proportional to the number of convolutions.

2. Type of bellows movement:

2.1 Axial extension:
Axial extension is the dimensional lengthening of an expansion joint along its longitudinal axis. Axial extension has been referred to as axial movement, traverse, elongation or extension.

2.2 Axial compression:
Axial compression is the dimensional shortening of an expansion joint along is longitudinal axis. Axial compression has been referred to as axial movement, traverse or compression.

2.3 Lateral movement:
Lateral movement or deflection is the relative displacement of the two ends of an expansion joint perpendicular to its longitudinal axis. This has been referred to as lateral movement, lateral offset, and parallel misalignment.

2.4 Angular deflection:
Angular deflection, angular displacement, angular rotation or rotational movement of the longitudinal axis of the expansion joint from its initial straight line position into a circular arc.

3. Flexibility increasing:
Flexible constants descend under the same thickness:
Single-ply bellows → Double-ply bellows → Multi-ply bellows
Advantages of multi-ply bellows:
Spring rate of multi-ply bellows is lower than of single-ply bellows.
Cycle life or fatigue life of multi-ply bellows is higher than of single-ply bellows.
Good movement
Optimum compensation in small spaces
Low adjusting forces
Indication of leakages through check hole
Isolation against impact noise

4. Bellows material:

The bellows material shall be designed, specified and must be compatible with the flowing medium, operating temperature, strength, corrosion, external environment, pipeline cleaning chemicals.
Bellows is usually made of stainless steel.

5. Main functions of bellows and expansion joint:
Compensation of thermal extension in pipelines
Compensation of relative movements between plant sections
Reductions of movements and forces at connections
Decoupling of equipment vibration from connected systems, such as compressor
Pressure reliability
Column stability
Inplane or local stability
Isolation of structure caused noise

6. Requirements of bellows and expansion joint:
Temperature resistant
Pressure proof
Corrosion proof
Vacuum tight
Maintenance free

7. Common failure reasons:
Stress corrosion
Fatigue damage
Carbide precipitation
Squirm and Rupture

8. Good solution:
Ask CDI-Bellows

Keywords: Metal Bellows  Metal Bellows Expansion Joints   

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Company Name CDI-Bellows
Country/Region Taiwan
Province / State Taiwan
City Kaohsiung County 831
Address No.84, Huadong Rd., Ta Fa Industrial District, Daliao Township
Telephone +886-7-7873488
Fax +886-7-7872755
Contact Person