Centrifugal vs Positive Displacement Pumps: What Are the Differences?

green centrifugal pump

green centrifugal pumpIn many industries, a pump is part and parcel of the process. It’s necessary to move gases, fluids, and slurries through mechanical energy.

There are different types of pumps that perform a variety of applications. These include the following:

Centrifugal Pump

Centrifugal pumps are devices that use an impeller blade. This component rotates at a specific speed to generate velocity. This kinetic energy via rotation then helps move the fluid. The system also includes a casing. This part is responsible for capturing the impeller’s velocity. When fluid passes through the impeller, pressure goes up, and it gains velocity.

An excellent way to explain how these pumps work is to think about propellers in a boat. These propellers turn at very high speeds to generate velocity. It then allows the vessel to move forward.

Contrary to popular belief, the movement of the fluid is not due to centrifugal force but rather by inertia.

Positive Displacement

A different mechanism of pumping fluids is the positive displacement. In this system, there are two main movements. First, the device suctions the fluid to pass through a part of the displacement pump then goes out towards the discharge pipe. In some instances, the pumps have cavities, which can expand as the fluid enters and then narrows to release the fluid.

These movements can create the pressure necessary to move the fluids, but the flow tends to remain constant despite pressure changes. Perhaps a significant disadvantage is the risk of internal leakage. It can quickly change the way the fluid flows.

In a centrifugal pump, you can avoid this problem since the casing ensures the fluid doesn’t leak outside.

A positive displacement pump can also use a rotary device. It may then create confusion with the centrifugal pump, which uses an impeller blade that also rotates. There are major differences, though. One, the rotary device only suctions, draws in, or captures the fluid. It doesn’t create help create pressure. Moreover, it needs to rotate at a much slower speed.

When you don’t know which between the two to use, always reach out to professionals. Working with experts ensure you have an efficient design and operation.