Main Components of Centrifugal Pump

The main components of a centrifugal pump are impeller, casing, suction pipe, foot valve, strainer, delivery pipe, and are discussed below.

Impeller: Impeller is a backward curved vane. It is mounted on the shaft coupled to electric motor. Thus, it is a rotating part of centrifugal pump.

Casing: It is air tight passage surrounding the pump. Its function is to convert the kinetic energy of water into pressure energy before entering the delivery pipe. Different types of casing used in centrifugal pump are volute casing, vortex casing, and casing with guide blade as shown in Figure 9.17a–c.

Volute casing is a spiral type casing. The area of passage increases gradually so that velocity of water decreases and pressure increases. The main limitation of this casing is eddies formation which causes the loss of energy.

Figure 9.17 Different Types of Casing Used in Centrifugal Pump

In vortex casing, eddies formation is eliminated by employing a circular chamber in between impeller and casing as shown in Figure 9.17b. Thus, efficiency of vortex casing is more than that of volute casing.

Casing with guide blades allows water to enter into the guide blade without shocks. Guide blade works as diffuser, since the area of guide blade increases which converts kinetic energy of water into pressure energy.

Suction Pipe, Foot Valve, and Strainer: A pipe, whose one end is connected to the inlet of pump and other end dips into the water in a sump, is known as suction pipe. A foot valve is a non-return type valve which is fitted with lower end of suction pipe. The foot valve opens only in upward direction. A strainer is also fitted at the lower end of suction pipe. It works as a filter.

Delivery Pipe: A pipe, whose one end is connected to the outlet of the pump and other end is connected to the supply at some height, is known as delivery pipe.