Like any piece of machinery on the shop floor, a dryer requires proper maintenance to ensure it is operating efficiently.
Advances in technology are positively impacting maintenance efforts, allowing operators to quickly detect changes in a dryer’s operation. Often, a potential issue can be detected before it even becomes a problem, reducing downtime and increasing efficiency.
The dryer includes process and regeneration heaters, air flow components, filters and blowers and moisture-absorbing desiccant.
It is vital to maintain an unrestricted flow of air during the drying process. Regular maintenance can ensure this. The filer elements should be cleaned on a regular schedule based on throughput. If the filters are damaged, they should be replaced. Operators should regularly check and tighten all hose connections.
If a hose has an obstruction, crimp or a collapsed lining, it should be repaired or replaced.
In a desiccate dryer, the beads should be replaced every two years. When the dew point of the process air will no longer achieve the manufacturer’s suggested temperature, or when regular filter cleaning and replacement fails to have the desired impact, bead replacement may be needed. You can perform the crush test by trying to crush some desiccant that has been dried through the regeneration cycle. If it crumbles between your fingers, it should be replaced.
When replacing desiccant, it is important to know what type of dryer you have. It could prove to be a disaster if absorbent deliquescent desiccant is put into a regenerative dryer.
How many towers does the dryer have? If there are two towers, you need an adsorbent. If there’s just one tower, you most likely need an absorbent deliquescent.
In a single-tower deliquescent dryer, replenish the deliquescent desiccant simply by adding more. Check the sight windows on the dryer vessel. When the desiccant is no longer visible, fill the vessel up to the weld seam.
For a twin-tower regenerative desiccant dryer, generally the desiccant no longer works. If the dryer is working, but not producing the required dew point, a shop will have to use a dew point meter to determine if this is the issue.
Dual bed dryers are a closed-loop system, requiring maintenance personnel to check all hoses, clamps and gaskets for leaks. Air also can enter the dryer through a vacuum loader.