The relative simplicity of design has made centrifugal pumps the most commonly available and widely used pump type in the market. Based on the number of impellers, centrifugal pumps can be classified into two categories - single-stage and multistage.
Single-stage pumps have a single impeller. Hence the discharge pressure is a function of the size of the impeller. So, such pumps are a better-suited solution in higher flow, lower pressure installations.
Multistage pumps are capable of providing a flexible range of flow and head and a relatively higher degree of energy efficiency, which makes them an excellent choice for many applications.
A multistage pump is a pump in which the fluid flows through two or more impellers fitted in series. Hence, such a pump will have multiple liquid chambers or stages connected in series. Each stage consists of an impeller, a combination of a diffuser, and return guide vanes, all housed within the same stage casing.
These impellers are installed in series and rotate on a single shaft driven by a power source (usually a motor). The design of multistage pumps allows the fluid to flow through the chambers only in a linear fashion.
After priming the pump, the fluid enters the pump inlet at suction line pressure into the first chamber. The fluid then passes through various impellers sequentially from left to right (or vice versa, depending on the design of the pump). Finally, the fluid leaves at some elevated pressure. Each impeller feeds into the next impeller, and at every stage, the pressure increases further.
The more the number of stages or impellers in a pump, the higher is the final discharge pressure. Although the fluid pressure increases with every stage, the flow range always remains constant for a given RPM.
Multistage pumps are available in many types, as listed below, but the most commonly used ones are vertical and horizontal pumps.
A multistage pump finds applications across a varied range of industry verticals requiring the movement of fluids. For example, High-rise buildings require higher pressure to deliver water to their overhead tanks. Multistage pumps are widely used for such applications. They are also often used to either boost the water system’s pressure or continuously circulate water in the system.
Other key applications include:
Need assistance in selecting a multistage pump for your fluid transportation requirements? Let our expert engineers assist you. As the oldest and largest pump distributor in the Northeast, Hayes has the broadest line of pump products from over 20 different manufacturers.