Cantilever Pumps

What is a cantilever pump?

A specialized types of vertical sump pump designed to be installed in a tank or sump but with no bearing located in the lower part of the pump. Thus, the impeller is cantilevered from the motor, rather than supported by the lower bearings.

How do they work?

A cantilever pump is considered a centrifugal pump configured with the impeller submerged in the fluid to be pumped. But unlike a traditional vertical column sump pump, there are no bearings below the motor supporting the impeller and shaft. A traditional vertical column sump pump has a sleeve bearing located just above the impeller, and additional bearings located further up the shaft if the pump is more than four feet long. These bearings in a traditional vertical column sump pump are often exposed to the liquid in the sump, as the column surrounding the shaft and bearings has holes in it that allows the liquid in the sump to get to these bearings to help lubricate them. This arrangement is not possible for certain very abrasive applications, so the cantilever pump was developed for these situations. The cantilever pump has a much larger diameter shaft, since it has no lower sleeve bearings that act to support the impeller and shaft.

In general, cantilever pumps are best for relatively shallow sumps, usually around 8 to 10 feet maximum. This is because the deeper the sump, the larger the shaft diameter that is required to cantilever the impeller.

Where are they used?

Cantilever pumps are primarily used in applications that involve abrasive, solids laden liquids. These applications are most commonly found in minerals processing plants, steel mills, chemical plants, and industrial wastewater treatment facilities.

Other smaller configurations of the pump with lower flow requirements are used in plating services and for high purity deionized water cleaning systems used in semiconductor manufacturing. These applications can’t have any metal in contact with the pumped liquid. The plating application because of the corrosive nature of the plating chemicals, and the deionized water bath application because of the high purity required for deionized water. So, both of these applications use small vertical cantilever pumps made entirely of plastic material such as polypropylene, with a ceramic shaft and, of course, no bearings.

Other related Pump Types include: well pumps, water pumps, vacuum pumps.