While dealing with power plant equipment, sugar factories, oil refineries, a major problem encountered is sealing of the tubes. A tight mechanical seal between the tubes can be achieved by tube expansion methods. In this process, a tube is expanded into the other tube. Their point of contact is sealed by applying intense pressure on it. Check out the info about the tube expansion systems, which are detailed below.
Tube Expansion Methods:
In any of the processes employed, the ultimate aim is to force the space between the tube sheets. A few processes are detailed here under:
- Hydraulic expansion: Hydraulic pressure is applied at directly at the surface of the section to be sealed.
- In case of explosive type of expansion, we place explosives along the tubular column of the section to be sealed. The high pressure developed during the explosion results in tight joint between the tubes.
- In the process of mechanical rolling, rolls are used to exert high pressure along the contact surface of the tubes.
Components Of The Tube Expander:
The basic components of the tube expander are listed below. It is to be noted that the design of the tube changes with the type of expander and the application.
- Roller: The internal surface of the tube is deformed plastically under the action of this component. It is so designed that, even under the expansion process, the internal surface of the tube remains in perfect cylindrical shape.
- Mandrel: The rollers are rotated with the help of these mandrels. They are designed to be tapered in shape similar to that of the roller design. The materials employed in the manufacture of the mandrels and rollers must withstand the high pressure and friction developed.
- Frame: Multiple rollers can be held at equal distances with the help of the frame. In general, the frame is designed to carry 3-7 rollers.
- Bearing collar: The high thrust developed during the expansion process is minimized with these devices to safer levels. Tube ends and tube sheets can be protected from damages by employing bearing collars.
Accessories:
- Eledrive: As the name suggests, electricity is the driving force for this device. The load torque during the expansion process is detected and the tube expansion is confined to its predetermined size while expanding with the help of this device.
- Tube roller: the driving unit of the tube expansion system is the tube roller. Clockwise and counter clockwise rotations are possible with this unit.
- Servo drive: Installing servo drives reduces the work time to appreciable levels. It is a high speed machine which yields truly precise results.
- Grooving tool: Often, we may have to make grooves on the internal surface of the tubes. This can be done with ease by employing a grooving tool which is supported by a drilling machine.
- Expander oil: Any moving part undergoes friction which results in wear and tear of the machine. If unchecked, the tool life gets diminished. Expander oil is a lubricant which is used to minimize the friction of the expansion system.
- Spring balancer: The effort of the operator to handle the expansion tools can be reduced greatly by using spring balancers.
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