For most managers of critical cleaning operations, drying may not be synonymous with evaporation. Drying of rinse water by evaporation can be the most costly, energy, and time-consuming stage in the cleaning of parts. Even worse, whatever is non-volatile in the rinse water (minerals, detergents, ions), is left behind as surface imperfections. In some critical applications that can be fatal; the point of cleaning work, after all, is to remove surface imperfections—not generate them.

MAY THE FORCE BE WITH YOU
The second general method for drying parts of liquid films is to apply force to the films so as to dislodge them from surfaces. At least three types of force may be used: centrifugal, mechanical, and surface tension.

CENTRIFUGAL DRYERS
This approach makes too much sense to have been ignored in industrial cleaning. One simply places the parts in a circular-shaped basket, rotates the basket, the water is pulled off by the centrifugal force, and the dry parts are removed.

Relative to evaporation, energy consumption is negligible. Some heat air and blow it onto the rotating parts which makes no sense as the point is to avoid the energy debit necessary for evaporation. Cycle time can be 30 seconds to ten minutes.

There is mistaken concern about the force causing part movement within the basket, and therefore possible damage. Actually the centrifugal force holds parts in place and keeps them from moving.

Yet, there are good reasons why centrifugal dryers aren’t commonly used in critical cleaning: (1) not all water is removed, perhaps only 95% (which could serve as a preliminary drying step), and (2) most cleaning machines are built to use square baskets, and not circular-shaped ones.