Vertical Multistage
Pumps

A vertical multistage pump is a centrifugal pump containing two or more impellers. The impellers may be mounted on the same shaft or on different shafts. The fluid flows into the inlet of the pump where it flows into the eye of the impeller. The rotation of the impellers creates a centrifugal force, directing the fluid along the impeller vane and pushes the fluid to the outer tip of the impeller vane where it enters the stage diffuser. This process continues until the fluid has passed through each impeller stage. Each stage that the fluid passes through increases the discharge pressure. 

Vertical Multistage pumps are used when higher pressure is required which single stage pumps of the same size are unable to attain.