Flexible Impeller Pumps for Fluid
Flexible Impeller Pumps are often referred to as the “workhorse” of pumps. They’re inexpensive compared to similarly capable pumps, long lasting (when properly cared for), and parts are easily replaceable and readily available. The pump uses circular impeller made of an elastomer (usually NBR, silicone, or EPDM) with flexible vanes inside a tightfitting pump head. Typically, the bottom half of the internal cavity is circular with a radius that matches the impeller, and a top half that is somewhat “flattened”, resulting in the flexible vanes folding and unfolding as they pass through the upper portion of the pump head during the impeller’s rotation. This generates a vacuum at the inlet port and positive displacement at the outlet, providing a gentler product flow when combined with the kinetic energy produced by the rotation of the impeller. Increasing the size of the pump head and impeller [along with the motor and other mechanical components] not only increases the maximum flowrate of the pump, but results in the ability to transfer must (solids and liquids) due to the larger space between the vanes within the pump head.
The downside to Flexible Impeller Pumps is that, like solid centrifugal impeller pumps, they still use kinetic energy to force the product around the pump head, and the pump head must always be primed when operating to prevent damage from dry running.
