FREDERIC W. BUSE
The use of composite materials is playing an increasing role in the manufacture of indus-
trial pumps due to the cost savings they offer in manufacturing, installation, and opera-
tion. Composite parts can be molded to near "net shape." This eliminates the cost of
secondary machining to attain the final part. Because one composite material can replace
two or three different grades of metal part, the combining of several parts into one assem-
bly is possible. This parts integration reduces assembly time, reduces inventory, and ulti-
mately reduces manufacturing costs.
Because composite pumps weigh less than metal pumps, they are easier to handle dur-
ing installation and maintenance. Further, because composites naturally dampen vibra-
tion, a composite pump operates more quietly than a comparable metallic pump.
The corrosion resistance of composites is superior to metals. For this reason, a com-
posite pump's life can be significantly greater than a metallic pump. When the amortiza-
tion costs of both composite and metallic pumps are calculated, the composite pump has
the cost advantage.
FACTORS TO CONSIDER ______________________________________________
Factors to consider in using composite materials for pump parts are mechanical proper-
ties, abrasion and corrosion resistance, temperature, costs, weight and insulating proper-
ties, exposure to sun, fire resistance, and chemical resistance.
Mechanical Properties The composite pump or parts must be designed to withstand
the loads/stresses of the operating conditions. If the existing metal part design were sim-
ply replicated in a composite, the composite part could fail. Excessive stresses for a com-
posite pump at the nozzle area or at the bearing housing can cause the pump housing to
creep. The result is part distortion or bending and shaft misalignment.
A solution to this problem is to calculate the stress levels in the composite part and