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“MK” Series Sealless Pumps: Principles of Design
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Patented Hydraulically Balanced MagDrive Operation
Reduces Bearing Failures by Eliminating Thrust Loads
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Figure 1. The motor shaft is coupled to the outer magnet assembly. A flux path is created between the outer and inner magnets through the walls of the containment can, thereby magnetically coupling the inner magnet and its attached impeller with the outer magnet.
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Before start-up, suction piping valve(s) are opened and fluid fills the core of the stationary shaft and flows from the inlet through the impeller to the discharge outlet. Fluid also passes through the wear rings located behind the impeller to the rear of the containment can surrounding the stator.
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At start-up, the impeller and the inner magnet assembly move to its rear-most position. This occurs because the larger surface of fluid on the front side of the impeller has greater pressure than in the area behind the impeller. The higher pressure pushes the impeller assembly back towards the motor stopping the passage of fluid between the stator area and the shaft bore.
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Figure 2. Once the fluid pressure in the stator area of the containment can increases, the impeller assembly slides forward on the shaft. This axial movement opens a channel between the stationary silicon-carbide ring and the rotating rear bearing, thus allowing fluid in the stator area to travel into the hollow shaft.
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Once this axial movement occurs, fluid pressure within the back portion of the containment can become balanced with the pressure in front of the impeller. As pressure varies between these areas, the impeller assembly moves axially to maintain balanced pressure, eliminating thrust loads that cause bearing failure.
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File Format Help
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AUTOCAD: Reader download: Keyview (Windows). To download a CAD file: PC: Right click on link and choose "Save link as" from Pop-Up menu. Mac: Click and hold mouse on link, then select "Save this link as" from Pop-Up menu.
ZIP: Some files need to be unzipped. Unzip utilities available for download for Windows / Macintosh.
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Wanner Engineering, Inc.
Wanner International Ltd.