“Magnetic Drive” refers to the coupling between the wet end of the pump and the motor. In direct drive pumps, the impeller of the pump is attached to the shaft of the motor, and this design depends on the shaft seal to contain the chemical. In a magnetic drive pump, the wet end and motor are two separate contained parts, connected by only a motor bracket.
At the end of the motor shaft, a drive magnet is attached, and as the drive magnet rotates around the rear housing, the impeller, which is fixed upon another magnet, spins in synchronization. Without a shaft seal and the possibility of leakage, magnetic drive pumps excel in applications involving corrosive, toxic, flammable, expensive, or environmentally hazardous liquids.
How Magnetic Drive Pumps Work
It is the attraction of the drive magnet and the impeller magnet which allows the full torque of the motor to be passed onto the impeller. As the shaft of the motor does not extend into the interior of the pump, there is no need for a shaft seal. As the impeller is not fixed to the motor shaft, the impeller floats inside the pump housings. The impeller spins, at the same speed as the motor, supported by a stationary shaft. The only moving part which touches the liquid is the impeller.
Without a shaft seal, the danger of leakage commonly associated with a shaft seal is eliminated. Furthermore, the maintenance cost is reduced because no time or money is spent on maintaining or replacing the shaft seal. For a pump that eliminates the problems and costs associated with mechanical seals, the March Magnetic Drive Pump has no equal.