Rotating-drum absorber

Although, the use of all the types in Table 7 and 8 are advised repeatedly (71,72,76), it is our opinion that some have only a historical value. For instance, a conical wetted wall column (77) has no advantage over that of a cylindrical one, but it has the disadvantage that the end effect due to a rigid film at the liquid exit will be increased. For instance, the results from a disk column are difficult to reproduce (78) thus a string of spheres column may be preferred. Other types which have only historical value include the rotating drum and moving band absorbers... 

In this case, an absorbent material is fixed to a drum or disk. Part of this drum is immersed in the water. When the drum is rotated in the water pan, it absorbs moisture, which is then transferred into the airstream by evaporation. 

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