How to Use the Magnetic Drive Centrifugal Pump Compass

Magnetic drive centrifugal pumps are an optimal solution when handling highly corrosive, toxic, polluting, or expensive liquids. It's important that the liquid is clean without suspended solids, which would otherwise obstruct the closed impeller.

With the magnetic drive pump, it is possible to handle fluids with viscosities up to 200 CPS (with the larger size) or specific gravity up to 1.8 kg/L by increasing motor power. With the same number of rotations per minute [rpm], increasing motor power does not affect the flow rate and head of the centrifugal pump but compensates for the increased effort due to denser liquids. For higher viscosity values, stronger magnetic forces would be required, exceeding the limit compromises the rotation of the impeller and thus the fluid transport;
A magnetic drive centrifugal pump is a very efficient but delicate machine. It is necessary to know the characteristics of the system and the working fluid to choose the right machine.

Due to their operating principle, centrifugal pumps create a suction depression. If the absolute pressure at the impeller inlet is lower than the vapor pressure of the working liquid, cavitation occurs (creation of evaporated liquid bubbles and implosion on the impeller). Fluimac magnetic drive centrifugal pumps should be positioned outside the fluid tanks and always installed under head so that the liquid does not have difficulty entering the pump's suction. However, the maximum suction height can be controlled through NPSH curves: The pump's NPSH (available) must always be greater than the NPSH required by the system, considering the geodetic height (difference in height between the downstream tank and the pump inlet), the head losses between these two sections, and the pressure difference between the free surface pressure of the downstream tank and the vapor pressure of the liquid.
In addition to suction conditions, it is essential to know the characteristics of the discharge pipes because they influence the calculation of the head. Before choosing a magnetic drive centrifugal pump, it is necessary to know the head required by the system: to the geodetic height (difference in height between the downstream and upstream tanks through which the fluid is to be moved) must be added all the head losses due to the system. We can divide the losses into two types: distributed and localized. The former depends on the flow of the fluid in the pipes, and it is necessary to know the dimensions and conditions of the pipes, the latter depends on localized factors in the system such as curves, valves, or filters.
Finally, it is necessary to know the working fluid. Viscosity and density also affect the calculation of head losses and also in the choice of motor power. It is important to remember that viscosity is strongly dependent on the operating temperature. Low temperatures significantly increase viscosity

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