Maintenance and repair of the dryer
HDK-CNG_EN_03_2016
49
Replace drying agent
Never take the dryer out of service without inerting it beforehand.
Together with air, natural gas can form an explosive gas mixture and
therefore poses a considerable danger. An explosive atmosphere can
build up especially when replacing the drying agent. To prevent this, the
dryer must therefore be purged with inert gas.
The service life of the drying agent is usually approx. 3 to 5 years. . The drying
agent can however, if installation conditions are favorable, take place must later
(for notes on installation location, also refer to page 17). The change interval
depends very significantly from the degree of contamination in the compressed
air (or the quality of the compressed air upstream filters). Oil, dust, and dirt
particles cover the drying agent surface and reduce its effective surface, in part
quite irreversibly.
Comply with the following safety notes when changing the drying agent:
Wear eye protection and dust mask due to increased dust generation!
When emptying the drying agent, increased dust generation may occur.
In order to avoid any eye irritations, wear protective goggles!
In order to avoid any dust inhalation, wear dust mask!
Risk of skidding!
If drying agent has been spilt on the floor, there is a risk of skidding
caused by the drying agent beads. Therefore, spilt drying agent must
always be taken up immediately.
Remove used drying agent
Avoid the creating of sparks!
An ignition source can arise through the friction caused by emptying and
filling drying and purifying agents. That in turn entails the hazard of
sparks being caused.
For work in Ex-protected rooms, the vessels must all be
earthed/grounded while being filled and emptied.
When emptying, only use Ex-protected suction tools.
► Depressurise the dryer and shut it down (see page 39).
► Provide a suitable collecting hopper.
► Unfasten connection between lower pipe bridge and upstream filter (1).
► Unfasten cap nuts between lower pipe bridge and vessels (2, 3).
► Drain drying agent into collecting hopper. Carefully remove residues with an
industrial vacuum cleaner.
► Then reinstall lower pipe bridge and connection to upstream filter.
► Dispose of the used drying agent in accordance with all applicable
regulations.
