The external regeneration design makes these dryers independent of compressor operation and in addition, the variable regeneration energy quantities as heat carrier result in flexible economical application possibilities, also in explosion proof areas. The dewpoint peak after switch over from regeneration to adsorption is so low that it can be neglected. The same pressure dewpoints using less energy, respectively lower pressure dewpoints for the same expenditure of energy, can be achieved under favourable conditions through the lower residual load on the drying medium. Purge air consisting of already treated compressed air becomes unnecessary, and pressure dewpoints down to -70°C are reached with continuous operation.There is no heat gain with vacuum regeneration and this has a favourable effect on cooling. However, during desorption, there is also no additional heat. When the dryer is installed in damp or high temperature conditions, then special care must be taken to ensure that the vacuum pump is working within its design parameters and is not affected by the conditions. The rise of the pressure gradient in the adsorber reduces the quantity of regeneration air, so that inadequate pump performance extends the heating period in proportion. Regeneration and cooling air, as well as high inlet temperatures accompanied by low operating pressure, have a considerable negative influence on dryer design.
