New tube assembly technology

Execution of typical expanded connections

Expanded connections are similar to riveting: in both cases the outcome is a connection due to a plastic working of the material. While riveting is history in pressure engineering, expanded connections between tubes and tube sheets are invaluable.

In typical "rigid tube sheet - soft tube" arrangements, when proportions of the length of expansion, thickness of tubes, and ligament between tubes are maintained, a self-feeding expander is used, connected to a drive with electronically controlled torque.

Approximately 80% of all connections in currently manufactured shell and tube heat exchangers are expanded connections.

execution of typical expanded connections execution of typical expanded connections

Supplementary tasks:

Cleaning and degreasing the surfaces of the holes in the tube sheets, and the tube ends

Smoothness and cleanliness of adjacent surfaces of a hole and a tube are essential to a tight and durable connection between a tube and a tube sheet.

cleaning and degreasing the surfaces of the holes in the tube sheets

Inserting the tubes

Tubes are inserted using guides that prevent the tubes from becoming blocked on partitions and from being damaged.

inserting the tubes

Blocking the tubes in the holes

By fixing the tube and eliminating the space between the tube and the hole in the tube sheet, one can prevent the tube from sliding and turning during the process of expanding.

blocking the tubes in the holes

Finishing of the tube ends

Process allowances of tubes are removed with facing heads. Sockets can also be made on such faced tubes, or they can be rounded off.

finishing of the tube ends