Centrifugal Pump Components

Generally, centrifugal pump components are include:

  1. Casing
  2. Impeller
  3. Shaft
  4. Bearing
  5. Clutch
  6. Packing & Seal
  7. Lubrication System

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Pump Casing

The first major component of a centrifugal pump is the pump case. Centrifugal pump casing is designed in the form of a diffuser that surrounds the pump impeller. This diffuser is more commonly known as a volute casing. In accordance with the function diffuser, volute casing serves to reduce the flow rate of fluid into the pump. At the pump outlet, the volute casing is designed to form a funnel that convert kinetic energy into pressure by lowering the speed and raising the pressure, also helping the balance the hydraulic pressure on the pump shaft.

Volute Casing
Volute Casing

 

Impeller

Impeller is the rotating part of the centrifugal pump, which serves to transfer energy from the motor rotation to the pumped fluid by accelerating it from the center of the impeller to the outer side of the impeller.

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Some examples of impeller types

 



The impeller design depends on pressure requirements, flow velocity, and conformance with the system. Impeller becomes the main component affecting pump performance. Modification of impeller design will directly affect the shape of the pump characteristics curve. There are various designs of centrifugal pump impeller, including closed and open type, single flow type, mix flow type, radial type, non-clogging type, single stage type, and multi stage type.

Shaft

The pump shaft is the part that transmits the rotation of the source of motion, such as the electric motor, to the pump. What we need to note is that, on a centrifugal pump working at its best efficiency point, the bending force of the shaft will be perfectly distributed throughout the pump impeller part.

Bearing

Pump bearing is to hold (constrain) the position of the rotor relative to the stator in accordance with the type of bearing used. Journal bearing serves to withstand gravity and forces in the direction of that heavy force, and thrust bearings serves to resist the axial force that arises on the pump shaft relative to the pump stator.

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Journal and Thrust Bearing

 



Coupling

Basically the coupling serves to connect two shafts, one of which is the driving shaft and the other is the driven shaft. The coupling used in the pump depends on the system design and the pump itself. The various coupling used in the pump can be rigid coupling, flexible coupling, grid coupling, gear coupling, elastrometic coupling, and disc coupling.

Packing System

The packing system at the pump is to control the fluid leak that may occur on the border between the pumping part (spindle) and the stator. Sealing systems that are widely used in centrifugal pumps are mechanical seals and gland packing.

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Mechanical Seal System

 

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Gland Packing System

 

Lubrication System

The lubrication system at the pump serves to reduce the coefficient of friction between the two surfaces that meet, thus reducing the risk of wear. Lubrication at the pump is mainly used in bearings. The system can be either lub oil or greas type depending on the pump design itself.