3 Signs You Should Use a Positive Displacement Instead of a Centrifugal Water Pump

Anyone who has worked on a construction site will know that it's relatively common to find that excess water needs to be removed before building work can start or continue. As such, water pumps are often vital, and you'll find there are several types from which to choose.

Probably the most fundamental decision will be between a positive displacement water pump or a centrifugal water pump. The former moves a fixed amount of liquid into a chamber and then forces it out through a discharge pipe, whereas the latter uses rotational energy to create pressure that moves fluid into the discharge pipe.

Each one offers its own benefits and drawbacks, but here are just three signs you should choose a positive displacement pump over a centrifugal pump.

1. You'll Be Tackling Thicker Liquids

Centrifugal pumps are great for moving thin liquids, but they generally struggle with anything much thicker than clean water. In contrast, positive displacement pumps can handle thicker liquids since their flow rate can vary automatically according to how thick the fluid gets. Additionally, positive displacement pumps can run at lower speeds than centrifugal pumps, which lets them handle any solid or abrasive contaminants in the water they are pumping. This in turn dramatically reduces wear on key parts.

This isn't a concern if you'll only ever be pumping slightly muddy water, but centrifugal pumps aren't recommended if you expect water to be very heavy with mud or other contaminants. They also aren't great when you may also need to pump different liquids. Under such circumstances, positive displacement pumps make more sense.

2. You Expect Dry Periods

Sometimes water pumps will need to be turned on and off throughout a construction job as water comes and goes, especially during rainy periods. That can be tricky with centrifugal pumps because they need to have liquid in to start building pressure. However, a positive displacement pump does not need to be primed with liquid in the system, so they're ideal for handling any dry periods.

3. Pressure Changes Are Expected

Both types of water pumps can remain efficient under ideal circumstances. However, positive displacement pumps are much better at handling any changes in pressure, flow rate, or viscosity. The same cannot be said of centrifugal water pumps – they tend to become significantly less efficient under any of those variations. Such drops in efficiency can represent a significant added cost during longer construction jobs.

Contact a contractor today for more information on pumps such as Davey water pumps.