1. Number of Impellers
• Multi-stage pump – This pump has three or more impellers for more efficient head service.
• Two-stage pump – This pump has side by side impellers operating for medium-head applications.
• Single-stage pump – It only has one impeller and the simplest design among the three pumps. This is the most commonly-used in pumping services.
2. Impeller Design
• Single Suction – These pumps allow fluid enter the blades only through one side.
• Double Suction – This type of pump comes with double suction impeller that allows fluid to enter from both sides of the blade. Split-case pumps are the most common type of pump that has a double suction impellers.
3. Shaft Orientation
• Horizontal – This is the most popular due to ease of servicing and maintenance. It is also considered whenever it is wished to be inside a facility. It is sometimes overhung or placed between bearing design. It can be coupled directly to a variety of drivers including an electric motor, engine and turbines like steam, gas, or power recovery turbines.
• Vertical – This pump utilizes a unique shaft and bearing support configuration that allows the volute to hang in the pump while the bearings are outside the pump. It is suitable for direct coupling to an electric motor. Lastly, it can easily withstand higher pressure service because of its simplified bolting and confined-gasket design.