Tube expansion is the process of joining tubes mechanically. They are most widely used in power plant equipment like heat exchangers, boilers, etc. In this article, we brief you about condenser tube expanders. By employing these devices, tubes of any complex design can be rolled and sealed effectively.
How to Select:
Before selecting the tube expanders, make sure that you consider the following factors strongly:
- Outer diameter of the tube.
- The thickness of tube walls and sheets.
- The material used in the manufacture of the tubes.
Features:
Check out for the following features:
- It should be designed to have a rugged construction.
- The device must absorb the torque developed so as to reduce vibrations.
- The rolling operation has to be performed with ease.
- The materials employed in the manufacture of the device should resist corrosion and withstand extreme working conditions.
Special Tool Expanders:
Here under, a few tools which are designed to meet specific applications are detailed:
- Linsen flaring expander: It is used to handle the tubes made of copper, brass and aluminum. The ends of these tubes are expanded so that another tube of similar cross section can be inserted into the expanded portion.
- Diesel engine expander: It is purposely used to roll injection sleeves into the diesel engine heads. They are specifically designed based on the dimensions of injection sleeve and engine head.
- Step rolling expander: Tubes can be rolled into thick tube sheets at a faster rate using these devices. In this process, the expander need not be removed from the tube. The expander cage in this device is grooved which facilitates faster step rolling.
- Collins expander: They are specifically used to handle thin sheets. These expanders are self feeding type.
Accessories:
- Extensions with quick change chuck: Expanders can be changed quickly with the help of this device. The extension lengths can be varied which makes the expander reach the tubes easily.
- Sleeve type extensions: If the tubes are too close to the shell of the condenser, employ these devices.
- Internal tube calipers: They are used to measure tube lengths quickly and accurately. In general, they are calibrated in metric and English systems.
- Tube wall caliper: They are used to measure the wall thickness of the pipes or tubes to be rolled.
Care and Maintenance:
- The presence of dirt or foreign materials doesn’t result in perfect joints. Clean the apparatus thoroughly before use.
- Lubricate the moving parts regularly to avoid friction.
- To ensure a prolonged life time of the expander, clean it regularly. Use the prescribed solvent by the manufacturer for cleaning.
- Damaged or chipped rolls must be replaced immediately. It is capable of damaging the entire set of mandrel and rolls.
- After every single operation, clean the device thoroughly and lubricate the specified lubricant.
- Select the speed of the expander in accordance with the tube size and type.
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