Sealless Centrifugal Pumps
Mag-drive or magnetically-driven pumps are a type of centrifugal pump. Their most notable feature is their sealless design. This greatly reduces the initial cost of the pump as well as its operational costs as there aren’t any mechanical seals, seal-fluid pots, or cooling lines that may break during pumping.
Mag-drive pumps come in a variety of materials of construction including cast iron / ductile iron, 316 stainless steel, and Hastelloy. This type of pump contributes to the technical standardisation in process engineering thanks to its universal applications. Also, mag-drive pumps are available in close-coupled and long-coupled (frame-mounted) configurations.
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.