Air coolers header box

The mechanical construction of the tubes in an air cooler create some rather nasty problems. Figure 14.4 shows the exterior appearance at either end of an air cooler. The small black circles are threaded steel plugs. They are not connected to the ends of the tubes. Allow me to rotate the air-cooler header box, shown in Fig. 14.4, by 90°, and display a cross-sectional view in Fig. 14.5. Note that the plugs are not connected to individual tubes. Unscrewing a plug just gives one access to the end of a tube, for cleaning purposes. 

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