Large Cast Power-Core (TM) Propeller Dives Into Paper Pulp Mixing

Most engineering polymers won’t stand up to the harsh conditions found inside the mixing tanks used in pulp and paper processes. High shear forces, elevated temperatures, aggressive chemicals and continuous wear can mean an early death for ordinary polymer pumps and impellers. And in fact, internal mixer components are typically made from expensive stainless steel grades or platings, not plastics.

Our Power-Core(tm) PA12GC Gravity Cast monomer, however, is different than other engineering plastics, and it has emerged as a emerged as a cost effective alternative to composites and metals in tank propeller applications. This ability to withstand the challenging conditions found in pulp and paper processing also makes Power-Core(tm) a natural fit for other types of mixers and processing machines.

Power-Core(tm) has four key characteristics that allow its use in these propeller applications:

• Resists Aggressive Chemicals. Power-Core resists the strong acids and bases found in pulp and paper processing. As a result, the material avoids the environmental stress cracking and brittle failure that would put an end to propellers made from less capable plastics.

• Fights Wear. Because of their continuous contact with viscous liquids, mixer propellers tend to suffer from hydroabrasion. Power-Core has an innate resistance to this wear mechanism.

• Scales Up. The propellers measure 1,500 mm across. So none of Power-Core’s chemical and wear resistance would make much of a difference in this application if the material didn’t lend itself to large structural parts. Regarding size, Power-Core’s proprietary gravity casting process can produce stress-free parts that measure more than 3 meters across. What’s more, the Power-Core gravity casting process allows the polymer to be cast over structural steel parts. The propellers, for example, have a structural steel hub to optimize the power transmission from the shaft to the blades.

Costs Less. No one would replace steel propellers unless there was a clear advantage to polymers. Power-Core has just such an advantage in the form of a longer life than steel, which tends to give into hydroabrasion prematurely. Power-Core also has a manufacturing advantage in that it can be cast net shape, eliminating expensive machining and finishing operations required by stainless propellers.