In a standard centrifugal pump, the power is delivered to the pump end either through a direct connection between the rotating element and the motor shaft or through a coupling between the pump end shaft and the motor shaft. In these cases, the pumping chamber needs to be sealed from the outside. Traditionally, packing or some other sort of mechanical seal accomplishes this.
To start with the basics, a magnetic drive replaces the shaft seal, which is the most high maintenance component on a centrifugal pump of this kind. This effectively prevents a Mag Drive Pump from leaking.
The principle of a magnetic driven pump is that the rotation from the motor shaft is transferred to the pump end via a magnetic coupling which eliminates the need for the shaft seal or packing. A drive magnet is mounted to the motor shaft, which transfers the motor torque through a sealed housing to an internal driven magnet. The driven magnet is coupled directly to the impeller. This configuration is categorized as seal-less.
The following will give an idea of approximate leakage rate for various Sealing arrangements:
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Gland Packing > 1000 ppm (Parts per Million)
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Single Mechanical Seal 10 - 1000 ppm
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Double Mechanical Seal < 10 ppm
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Seal-Less 0 ppm
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