325 Pump Components

The resistance of CFCCs to corrosion and their near transparency to electrical eddy currents make them an attractive candidate containment shell for canned and magnetic driven pumps. Canned motor pumps, widely used in chemical processing, move hazardous liquids where a leak cannot be tolerated. The pumps are used for acids, alkali salts, alcohols, aromatics, monomers, polymers, hydrocarbons, halogenides, and other chemicals. These liquids are often at high-temperature.

The outer case of the pump contains coils of electrical wires analogous to the stator windings of an electrical motor. The inner, rotating, portion of the pump contains coils of electrical wire like the rotor of an electrical motor. When an electrical potential is applied to the stator, the rotor spins, driving the pump impeller attached to it. A containment shell separates the stator from the rotor, is the guide/housing for the rotor, and seals the pumped liquid away from the pump driving mechanism. Shell materials need high hoop strength, corrosion resistance, and low electrical conductivity.

Metallic containment shells conduct electricity, causing a substantial loss of power. CFCC shells are not electrically conductive so they eliminate any eddy current and drag and thus reduce the electrical energy required to operate the pump as well as reduce heat transfer to the liquid. Dow Corning Corporation engineers teamed with Sundstrand Corporation to evaluate CFCCs as canned pump shells handling hazardous liquids in processes up to a maximum temperature of 450°C (840°F). The technology can be extended to magnetic pumps.

The thermal stability, toughness, corrosion resistance, and unique electrical properties of CFCCs and their use in canned pumps will result in reduced downtime, increased throughput, reduced energy use, and reduced operating costs. This application also demonstrates the ability to fabricate CFCCs into thin-walled structures.

0 0

Post a comment