Transformer Corrugated Pipe (Expansion Joint) Industry Guide
1. Overview & Standard Sizes
Transformer corrugated pipes (also called expansion joints) are flexible, bellows-style connectors installed between the transformer tank and radiators, conservators, or oil pipes. They absorb thermal expansion/contraction, vibration, and mechanical stress while maintaining a leak-tight oil seal.
Standard Models & Dimensions
Based on the provided size table, common specifications include:
| Model Type | Nominal Size | Key Dimensions (mm) | Notes |
|---|---|---|---|
| DW-80 | DN80 | H:160, L:160, B:160, D:160, Bolt Hole: Φ19 | Large flange straight pipe |
| W-80 | DN80 | H:160, L:160, B:160, D:160, Bolt Hole: Φ19 | Bent pipe |
| W-50 | DN50 | H:150, L:150, B:125, D:125, Bolt Hole: Φ14 | Bent pipe |
| Z-801 | DN80 | L:500, B:150, D:150, Bolt Hole: Φ22 | Straight pipe |
| Z-50 | DN50 | L:500, B:125, D:125, Bolt Hole: Φ14 | Straight pipe |
Flange options include fixed/flanged, movable/flanged, or one fixed + one movable end, as specified in the note.
2. How to Use & Install
Orientation: Install the corrugated pipe in the direction of thermal expansion (typically along the pipe axis). For bent models, ensure the bend angle matches the pipeline layout.
Alignment: Align the pipe with the mating flanges on the transformer and radiator. Avoid forcing misaligned connections, as this can damage the bellows.
Bolt Installation: Insert bolts through the flange holes and tighten them evenly in a crisscross pattern to distribute pressure and prevent leaks.
Free Movement: Ensure there is enough space around the bellows to allow full expansion/contraction without obstruction. Do not weld or fix the pipe to rigid supports that restrict movement.
3. Critical Usage & Maintenance Notes
No Welding on the Bellows: Never weld or modify the corrugated section, as this can weaken the metal and cause leaks.
Avoid Over-Tightening Flange Bolts: Excessive torque can deform the flange or crush the sealing gasket.
Prevent Mechanical Damage: Keep the bellows clear of sharp edges, debris, and tools during installation to avoid punctures or tears.
Check for Leaks: After installation, perform a pressure test to ensure there are no oil leaks around the flanges or bellows.
Regular Inspection: Periodically check for signs of cracking, corrosion, or fatigue in the corrugated section, especially after extreme temperature cycles.
4. How to Select the Right Corrugated Pipe
Nominal Size (DN): Match the pipe diameter to the transformer/radiator connection (DN50 or DN80 are common).
Pipe Type:
Choose straight pipe (Z-type) for linear connections.
Choose bent pipe (W-type) for angled pipeline layouts.
Flange Configuration:
Both ends fixed: For rigid, non-adjustable connections.
One fixed + one movable: For systems requiring alignment flexibility.
Specify your flange preference clearly when ordering.
Length (L): Select the length based on the required expansion allowance and pipeline layout.
Operating Conditions: Confirm the pipe material (usually stainless steel or carbon steel with anti-corrosion coating) is compatible with transformer oil and the operating temperature range.
5. Ordering Checklist: What to Provide
When placing an order, please include these key details to ensure the correct product is supplied:
Full model code (e.g., TH.WWB.001, DW-80, W-50, Z-801).
Nominal diameter (DN) (DN50 or DN80).
Pipe type: Straight (Z-type), bent (W-type), or special angle.
Flange configuration: Both fixed, both movable, or one fixed + one movable.
Required dimensions: Length (L), height (H), or special custom sizes.
Quantity and delivery requirements.