Centrifugal pumps can be used for a variety of jobs across multiple industries. Due to their high efficiency and versatility, centrifugal pumps have become one of the most commonly used pump types across a range of commercial and industrial applications.
Different centrifugal pump types are available depending on the needs of a certain industry. Because of this, industrial pump manufacturers produce an extensive range of centrifugal pumps suited to various applications.
So let’s have a look at some of the different types of centrifugal pumps.
What is a centrifugal pump?
To understand the different types of centrifugal pumps, you must first understand how they work. In simple terms, these pumps use centrifugal force to move fluid through to the outlet or downstream pipes.
Centrifugal pumps are made up of two major parts: the motor and the pump. The shaft connects the two, extending from the motor all the way to the rotor inside the pump. This rotor is called the impeller and it’s responsible for creating the pressure and flow that’s needed to move the fluid. The impeller is generally submerged in the fluid during the process.
The motor converts electrical energy into the mechanical energy that then rotates the shaft. As the shaft spins the impeller, it radially pushes the fluid away from the eye of the rotor and towards the edges. This creates a low pressure area at the centre, which then allows the pump to take in water via the inlet.
When the water leaves the edge of the impeller, it will hit the inside of the pump casing at a high velocity. As it hits the wall, that kinetic energy then turns into potential energy (pressure). This pressure creates a flow of fluid through the pump’s inner chamber called the volute. The volute goes around the circumference of the impeller and increases in diameter as it reaches the outlet. As the volute expands, it decreases the velocity of the fluid which, in turn, increases pressure. This whole process is what allows the pump to efficiently transport fluids.
One way we can classify different centrifugal pumps is by looking at the way they move fluids. There are the three common flow types:
- Radial pumps
A radial centrifugal pump takes in the fluid through the inlet and then creates a flow via an outward motion. As the water rotates in the impeller, it will start to move radially until it reaches the edge. At this point, the built-up pressure will force the fluid out from the volute. In radial pumps, the output of fluid is perpendicular to the pump shaft.
Such pumps are great for applications that require high discharge pressure. They are generally used in air conditioning, irrigation systems, refrigeration systems and dairy plants. However, in instances where the pumps need to move a large volume of fluids, radial pumps may not be the best choice.
- Axial pumps
Axial pumps, on the other hand, use a lifting motion to transport fluids. The impeller in axial pumps has veins that create a propeller action. This type of movement converts rotational force into a linear thrust, ‘propelling’ the fluid through to the outlet. Unlike radial pumps, axial pumps move the fluid parallel to the pump shaft
When compared to radial types, axial flow pumps cannot provide the same level of discharge pressure. It can, however, move significantly larger amounts of fluid. This makes it suitable for sewage treatment, water circulation and dewatering.
- Mixed centrifugal pumps
As one would expect, mixed centrifugal pumps combine features of both axial and radial pumps. Mixed flow pumps use a propeller action along with radial force. As a result, the fluid flows in a semi-axial direction. This creates a pump that’s able to move large amounts of fluid with a relatively high discharge pressure.
Number of stages
Another way to classify centrifugal pumps is through their number of stages. In this case, stages refers to the number of impellers or rotors used in a single pump.
- Single stage
As the name suggests, single stage pumps only use one impeller. As such, it can only provide a certain level of discharge pressure. However, it can efficiently transport large amounts of fluid. Because of this, single stage pumps are ideal for low-pressure operations with a large flow rate.
One of the other benefits of single stage pumps is that it is relatively simple to operate. This can be beneficial when ease-of-use is necessary. For example, due to high-pressure situations, fire departments might want a pump that can be used quickly and efficiently.
- Multi stage
Multi stage pumps use multiple connected impellers in a single shaft. Potential energy increases each time the fluid flows through an impeller. By the time the fluid reaches the outlet, the discharge pressure will be much more significant compared to that of a single stage pump.
These pumps are designed for operations that require high discharge pressure. It’s also commonly used in instances where the fluid needs to travel large distances like in water towers or large buildings.
Additionally, since it uses multiple impellers, the motor won’t need to expend a lot of energy to create pressure. Thus, multistage pumps are generally more efficient and are less likely to break down prematurely.
There are different centrifugal pump solutions for a variety of commercial and industrial operations. If you work in a field that requires transporting liquid, it might be worth getting a purpose-built centrifugal pump to improve the efficiency and effectiveness of your processes.