Header: one of the important parts of the air cooled heat exchanger (air cooler). The structure of the header determines the pressure capacity of the air cooler. There are mainly the following forms:

1. Pipe header

This is a cylindrical header used for high pressure (> 200bar) in such cases, the possibilities for distributing and circulating the fluid are very limited.

2. Welded bonnet header

This is half tube that is welded to the tube plate. It is mainly used in vacuum applications where sealing against air intrusion is paramount.

3. Cover plate header- for very dirty flows

As the name suggests, this design is in the form of a plate that can be removed in a single place, thanks to its assembly, by bolting to the rectangular flange of the header. This design is ideal for very dirty flow as it is easily accessible for clean.

4. Plug headers-generally the most used

This is the most common design due to its high service pressure resistance. It allows many passes as many passe as necessary. Each tube can be serviced by removing the 2 corresponding plus for cleaning and for inspection.