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The life of asphalt pumps at HMA plants depends almost entirely on the strainers used. Our asphalt pumping systems normally include two strainers: one for the unloading pump, another for the metering package.
Heatec makes two sizes of strainers: a fine and a coarse (Figure 1). The coarse strainer has 1/4-inch openings. The fine strainer has 5/64-inch openings. We currently provide the fine strainer as standard unless our customer specifically requests coarse strainers instead. We do not recommend the coarse strainer for normal use.
Obviously, fine strainers provide far better protection for asphalt pumps than the coarse strainers. But fine strainers are inherently more apt to clog and have to be cleaned more often than coarse ones.
However, after a new system has been in operation for a month or two most of the debris in the system should have been filtered out by the fine strainers. Thus, the same strainers should not need to be cleaned as often as they did during earlier operation.
When you use coarse strainers you put your asphalt pumps at risk. In the worse case, debris that can pass through the 1/4-inch openings in the strainers (Figure 2) may immediately damage your pumps (Figure 3). In any case, the life of your pumps will be shortened significantly.
Warranty on pumps is covered by the pump manufacturer or supplier. The Heatec warranty does not cover parts we do not make. So, if you experience failure of an asphalt pump, you need to contact either Heatec or the manufacturer.
The warranty on Viking pumps limits the size of the openings in the strainer to 10 mesh or 0.075-inch. This is comparable to the openings in our fine strainer. Consequently, if you choose to use a strainer with openings of a larger size, Viking is not obligated to cover the pump under warranty.
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