Challenging viscous or abrasive slurries require the right pump for the job. While centrifugal pumps are a common choice for thickener underflow pumping, peristaltic pumps offer a host of advantages that are worth considering when selecting a pump. In this comparison article, we examine the differences in cost and environmental impact between these two pumps to help you make the right decision for your next pumping application.
What are Peristaltic and Centrifugal Pumps?
Peristaltic pumps function on the principle of peristalsis. Rotor rollers or shoes compress the tube inside the peristaltic pump which creates pressure that pushes the fluid through the tube—sort of like squeezing out the last bit of toothpaste from a toothpaste tube. As the rotor moves forward, the compressed section expands to its original volume, creating suction that draws in fresh slurry. Centrifugal pumps, on the other hand, operate on a transfer of rotational energy from one or more driven rotors (referred to as impellers). These impellers increase the fluid velocity and pressure towards the centrifugal pump’s outlet.
Choosing a Pump for Thickener Underflow
For thickener underflow pumping, you can’t go wrong with a peristaltic pump. While the initial purchase cost is generally a bit higher than centrifugal pumps, that investment is returned (and then some!) by lower maintenance costs. This is in large part due to the impellers in centrifugal slurry pumps requiring expensive and frequent replacements.
Beyond the cost benefits, peristaltic pumps are more suitable for slurries with a high solids percentage, better at handling a variety of abrasive and viscous solids, and can also run in reverse in case of a blockage or if lines need to be cleaned with water. There are other benefits to choosing a peristaltic pump for thickener underflow such as their lower energy consumption, lack of mechanical seals, linear variable flow rate, and the ability to pump a higher percentage of solids. While centrifugal pumps can be less expensive for the initial buy-in, peristaltic pumps are the more cost-effective option in the long run and provide a variety of additional benefits to boot!
Reducing Costs and Environmental Impact With Peristaltic Pumps
Centrifugal pumps lose efficiency when the density of the slurry reaches 30% solid contents, which significantly increases process water demand on the pump. Peristaltic pumps can use 25% of the water and 60% of the electricity a centrifugal pump requires for the same duty (“duty” referring to the amount of solids that need to be pumped). Since peristaltic pumps can operate at a higher percentage solids, less water is required to move the same amount of solids.That can save 1.1 million litres of water per centrifugal pump replaced. Besides reducing the environmental impact, that can also mean significant power savings for you.