How To Choose The Right Tube Expander In Tube Expansion?
What is a Tube Expander?
A lot of times while fixing and molding tubes to tube sheets in the manufacturing processes of heat exchangers like boilers & condensers we use rolling tube type expansion tools, and these tools are popularly known as tube expanders.
Tube Expanders & their Components
A tube expander is a very important tool used in any heat exchanger. And usually, any tube expanders contain four main components.
Roller
A roller has a tapered shape and is designed so that the insides of expanded tubes always acquire a spherical shape. It applies a rolling pressure to facilitate plastic deformation of the inside of the tube.
Mandrel
This component of a tune expander also has a tapered shape, just like the roller. It is mainly used to rotate the roller through contact fiction. Both mandrel & roller are required to be pressure & abrasion resistant, that’s the reason why they utilize special steel & undergo proper heat treatment.
Frame
The frame is responsible for keeping the position of the rollers at regular intervals and thus, it also helps in preventing failure. It also works towards providing a feed angle to the groove at which the roller is inserted, thus, a configuration is achieved in which the mandrel is rotated clockwise.
Bearing Collar
A bearing collar is not what makes up the tube expander, it actually is attached to the tube expander. If you want a lowering thrust at the time of tube expansion, as well as less damage occurring to the tube & tube sheet, attaching a bearing collar to your tube expander is just the way to go. Also, by adjusting the installation position forward or backward, it is possible to achieve an effective length and reach length for the roller.
Different types of Tube Expansion You will find around!
There are a vast variety of tube expansion processes followed by different companies & individuals. But, majorly these are divided into two categories, better known as parallel tube expansion and flare tube expansion.
Parallel Tube Expansion
Parallel tube expansion is primarily used during the expansion of tubes in heat exchangers, steam condensers, boilers, and other similar devices. Tube Expanders for this type of work include the MB-type, CB-type, and HB-type.
Flare Tube Expansion
Flare tube expansion helps you expand tubes by supplying a flare shape to the ends of the tubes all while acting as tensile stress reinforcement. This type of tube expansion is most commonly found in boiler tubes.
Choose the right Tube Expander before a Tube Expansion takes place!
Before we decide to roll up our sleeves, start rolling & setting up the expander, it is very important to choose the right tube expander. And with so many options available one can easily find themselves in a hard dilemma. To get you out of the same dilemma, we have a series of steps that will help you choose the right tube expander.
Tube Projection
One of the most primary steps in the process of choosing a tube expander is considering if the tube is going to be expanded flush to the tube sheet or if it will have a projection.
Roll Length
Usually, the tube expanders come in two different roll lengths: short and long roll. In order to determine the correct roll length, you will need to know the tube sheet thickness.
Reach Requirements
More than often the tube expanders come in 4”, 8”, 12”, and 18” reaches, but can be made longer to accommodate specific applications.
Space Constraints
Heat Exchangers exchangers with channel boxes or division plates where the tubes are positioned too close to a wall for the expander’s collar to access perimeter tubes will require a friction collar.
Subzero Solution is one of the leading companies in Electric Tube Expansion System Machine.
