A tool for expanding heat exchanger tubes, boilers, etc., which are of shell and tube type. Expanders expand the pipe to prevent fluid leakage by expanding. There are various methods of pipe expansion, which in most cases, due to the lack of quality expanders, the old method is used, which is welding. In this method, the heat from welding usually causes burns and cracks in the pipes and the network, and finally causes leaks in the pipes, which must be replaced, which causes a lot of damage. In addition to the unsafe work, the welding process is long and expensive. In this regard, we have designed and produced high quality tube expanders or waltzes that are competitive with European and American models.
Advantages of using tube expanders:
1. Prevent fluid leakage
2. Expand tubes in the shortest possible time
3. Completely safe and without damaging the pipes
4. Reasonable and cost-effective compared to other methods
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Application of tube expanders:
Used in the construction and sealing of condensers, boilers, heat exchangers, air conditioners and pressure vessels, which are used in refineries, power plants and sugar and food industries.
Important requirements for using tube expanders:
- Ensure that the tubes and plate are standard.
- Remove rust from inside and outside the tube.
- Rust around the tubes may damage the expander components and cause a tight connection.
If the tubes are lubricated, they must be cleaned because the oils prevent the expander pressure on the tube.
- Expanders should be selected at a speed appropriate to the size and material of the tube. Proper speed makes work safe and is an important factor in the expansion life of tubes. After rolling each tube, check the rolls and mandrels and replace any crushed rolls or mandrels immediately. Failure to replace will damage the components of the tool or the whole.
- If, after inspection, you find that the tube is not expanded enough, you can make sure that the tubes are fully expanded by re-rolling, but care must be taken to observe the allowable expansion limit and prevent damage to them.
Proper maintenance of tube expanders:
- Expanders must be washed in a suitable solvent before use to remove protective coating, contamination, grease and ensure that the rolls and mandrels are in good condition and working properly.
- For longer life of the expander, the surface of the tubes should be free of any scratches, dents, cracks and other defects.
- Each time after rolling, the expander should be cooled in a solvent or light oil and then lubricated properly, but it is better to use two expanders so that another one is used during the cooling time.
- After finishing the work, the expander should be cleaned with light oil and its parts should be prevented from rusting.
Calculate the outer diameter of the expander:
Practical rule: Harder materials need less diameter reduction.
Guide to reducing the percentage of diameter:
|Copper and Nickel
|Steel, Carbon Steel, Admiralty Brass
|Stainless steel and titanium
|3003 or 4004 aluminum
The above are for guidance but are not required in certain cases.
If the material of the pipes is one of the following, 4 or 5 roll expanders (bullets) are used:
Super alloys with thick tube sheets,
Materials that harden quickly,
Thin tube sheets with triangular steps