Adsorption is a physical phenomenon. Gaseous molecules are attracted to solid surfaces by Van der Waals forces. It includes polar-polar attraction, ion-ion attraction, polar-ion attraction, gravitational attraction, and other intermolecular forces. These have strong adhesive forces due to which gaseous molecules adsorb onto solid surfaces even at very low concentrations in a carrier gas.
The adsorption dryer absorbs the moisture in the compressed air up to a pressure dew point of -40°F. Finally, in the after-filter, remaining particles from the drying agent are retained.
Adsorption dryers mainly consist of:
- Dryer inlet
- Condensate drain
- Lower shuttle valve
- Drying agent cartridge
- Upper shuttle valve
- Dryer outlet
- Processor control
The drying of compressed air is a multi-step process :-
- A compressor pressurizes ambient air containing moisture to an
elevated pressure, and temperature.
- The air is then cooled below the elevated vapor pressure of the
- A large amount of condensation is produced.
- The drying process begins with a mechanical separator.
- Then a coalescing filter is used to remove the bulk liquid and
water mist from the compressed air stream.
- A regenerable adsorption unit is used to reduce the water vapor
content to a very low level.
- A final filter removes the adsorbent fines entrained in the purified compressed air
- In laser cutting systems
- In bottling plants
- In dental laboratories
- In packaging machines
- In rail vehicles
- In optical measuring systems
- In sprinkler system