Most blower systems have inlet air filters. Preventative maintenance for inlet air filters involves cleaning, or replacing, them regularly.  Just like the automotive air filter, clogged air filters easily effect the operation. If the blower can't get air, it can cause a variety of problems. Oftentimes it is not readily apparent that the cause of the problem is due to the air filter. That is why the filters should be replaced, or at least checked, every year. In some environments they can go bad in less than six months.

The use of filtered air in centrifugal air blowers is not so much to protect the blower from dirt and grime, but more to protect the system diffusers, piping, and other components in the blower system. Some blower manufacturers and suppliers, have been using special air filters that can be quite costly. Using a pre-filter, or foam wrap, can help considerably to extend the life of a filter. This throwaway wrap is relatively inexpensive, $5-$10, but will catch most of the bees, insects, and cottonwood seeds that can shorten the life of the filter. Flat panel filters often have their own 1" or 2" thick pre-filter that can be replaced without replacing the larger(and more expensive) 6" - 12" deep filter panel.

Polyester coated cloth filters may cost more than paper filters, but cloth filters accept approximately 4 times the amount of dirt that paper filters do.  According to an engineer I've talked with about this, he proved it by monitoring how long it takes the differential pressure to increase to a given point(Dwyer gauge).  The filter manufacturers already know this when they size up filters for different applications.  Cloth filters last 4 times longer than paper.   Another advantage of the polyester coating is it allows you to wash the filter and reuse it, if desired. I strongly recommend cloth filters over paper filters for this reason. Some of my customers previously paid $100 per year for paper filter until I provided a $125 cloth filter that only needs replacing every 2 to 3 years, or more. Having a second washable cloth filters on hand allows one to keep a washed and dried filter as a backup.

Often overlooked in landfill gas applications is the filter media in the water separator tank. When it clogs with dirt and grime, the blower cannot draw enough gas to operate the flare. Or it can't provide enough pressure to supply the downstream system. More often, landfill gas systems have so much moisture mixed with the gas that water separation can be more of an operational problem.

Regular monitoring & inspection is the best defense in preventing unexpected problems.  Installing an inlet filter guage(Magnehelic), is an inexpensive way to ensure you always have adequately clean filters. Invest in PM, it can save you money.