How Are Heat Pipe and Heat Exchanger Tubes Closed? Copper and Stainless Tube Closing
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Tubes in heat pipes and heat exchangers must hold the working fluid's pressure through repeated heating and cooling, so the closure cannot have weld porosity or a plug gap.
Common closing methods
| Method | Description |
|---|---|
| Plug or welded cap | Needs welding and leak testing; welds may have porosity |
| Spin closing | A closing machine cold-spins the tube end into a one-piece seamless closure, no heat |
Round end or flat end
- Round end: more even under pressure, suits stainless and pressure-bearing heat exchanger tubes.
- Flat end: a flat face, suits small copper heat pipes whose end sits against a heat sink.
Copper and stainless tips
- Copper: very ductile and easy to form; watch end appearance and size consistency.
- Stainless: softer grades form more easily; no heat is used, so no heat discolouration.
- On seamed stainless tube the weld seam must be sound.
TONG DA heat pipe and heat exchanger closing machines
| Model | End shape |
|---|---|
| TD-31040 for heat pipes and heat exchangers | Round end, optional center hole |
| TD-21025 flat-end closing machine | Flat end, optional hole |
Why TONG DA
- TONG DA has designed and built tube processing machines since 1989 and runs contract processing on its own machines.
- Tooling is designed to your tube and drawing; sample trials available.
- CE certified; machines sold to the USA, Germany, Turkey, the UK, India, China and more.
FAQ
Is welding needed after closing?
A fully spin-closed end needs no welding; for higher pressures see Closing pressurized tubes.
Can I send samples for a trial?
Yes, please send the tube specification and closed-end drawing.
How do I request a quotation?
Send the tube OD, wall, material, length and closed-end drawing to sales@tdco.com.tw and we will reply promptly.