centrifugal pump
Shipping Industry

Centrifugal Pump Working Principal, Maintenance

This article discusses about the complete information related to  centrifugal pumps.

Types of Pumps

Following are the main pumps which are used in any industry:
1) Centrifugal Pump
2) Reciprocating Pump
3) Screw Pump
4) Gear Pump

Centrifugal Pump

The centrifugal pump is the most common pump in any industry and the reason for it is that they are easy  pumps and requires less maintenance. Talking about the pump in terms of shipping, then they are mostly used in ship and comprises of around 60 % pumps which are used on ship. This pump is not a self primed pump. So before starting, you have to prime it.

Parts and design of the centrifugal pump

Following is the part of the centrifugal pump:

Inlet and outlet opening
Casing
Impeller
Wear ring
Water seal
Motor as a driver
Coupling
Bearings

centrifugal pump
The Centrifugal Pump (Radial-flow turbomachines)

centrifugal pump

Material used in making of centrifugal pump

Casing: Casing of the centrifugal pump is made of cast iron. Cast iron has the good property by taking the desired shape, so easy to mold into any shape.
Wear rings: these rings are usually made of the metal brass.
Mechanical seal: This can be made of brass metal. In this bearing there are two dissimilar metals which are fitted together at close
clearance. Graphite or ceramic materials are also in great use!!

Working principle of centrifugal pump

This thing is taught during the course and it is the base which makes you to understand the working of the centrifugal pump. Actually centrifugal pump uses the centrifugal force to make water pressurized. This effect can be seen in the diagram in the design part. Now the basic function of nay pump used in any industry is to give higher head to the fluid to pump or to make it pressurize. A centrifugal pump is mostly used to make large discharges.

Before starting of the pump we have to do the priming of the pump. The reason for doing is that, this pump is not a ‘positive displacement pump’. So the flow can go both sides. But at the start of the pump we have to provide certain water or the fluid to be pumped into the inlet line, so that water or fluid can be pumped. This thing has to be taken care of while stating. The air vent valve is also opened which is situated at the outlet, to remove any air trapped in the pump.
So an impeller is fitted in the pump and this impeller turns the water present in the cavity. This energy from the impeller is transmitted
from the impeller to the water and then water is pushed forward. So this is how the pumping of the water takes place. The arrangement of the pump can be seen above. So the impeller takes the water from the inlet and forwards it to the outlet.
Note: The outlet of the pump is having fewer diameters then the inlet. The reason for this anomaly is that, the pump needs larger area for suction so that more water can enter and the outlet is smaller because the pressure is more. So water can easily go out.

Maintenance required on the centrifugal pump

Since centrifugal pump is a mechanical device and that too which contains the moving part, so we have to carry out the maintenance time to time, so that pump performs well. Following are the maintenances which are carried out in the pump:
1. Wear ring which is fitted in the centrifugal pump is used to provide the close clearance between the impeller and the casing. But as time
passes this ring starts getting wear and tear. So we have to use the new ring and replace it. This is the major maintenance which is carried out on the pump.
2. Gland packing is used in the pump to provide a seal on the shaft where shaft drive driving the impeller protrude out. So there is a mechanical seal there. This also gets to wear down time to time. So we have to take care of this gland packing.3. Impeller which is the heart of this pump has to be removed sometimes and changes completely. The reason for this is that the serious effects of the pitting on the impeller due to water or fluid led to damage to metal surface. So pitting or cavitations is a very bad phenomenon in this pump.
centrifugal pump

Uses of pump

These pumps are mainly used for general service like the ballast water system, cleaning purposes at deck and engine room. So these pumps find their use where there are high flow requirements but a low head at discharge is needed.

Advantages of Centrifugal Pumps

Following are the advantages of the centrifugal pump:
  1. The centrifugal give us a higher flow rate and this much flow is not given by nay other pump.
  2. The maintenance of the centrifugal pump is very less and can be operated at low maintenance.
  3. These pumps give us continuous flow.
  4. The initial cost of installation and their huge size does not affect performance at any cost.

Disadvantages of the centrifugal pump

  1. The head generated by the centrifugal pump is very less or you can say that the pressure developed by this pump is very less.
  2. There is a need of priming, starting the pump.

Conclusion

There is no doubt in this fact that the centrifugal pump has least maintenance and operating cost. But on the other hand if you want more pressure and high heat at discharge, then you have to use.

Mark Eriscson
Love to write about topics related to maritime sector. Was born in sailor's family, so love to ride on those high seas. In free time i would like to go for a good sunbath and some soothing guitar music. Want to have my own boat one day.

8 Replies to “Centrifugal Pump Working Principal, Maintenance

  1. if i want to use centrifugal pump to fill a tank which is situated at the 3rd floor of my house, is it possible? If it is possible then ok if it is not then why it is not possible? kindly explain….

    1. Yeah you can use this type of pump to get your water to reach at the 3rd floor. Most of the pumps used in the cities to fill the overhead tank are centrifugal pumps.

    1. Rotary pump is a broad category of pumps viz. reciprocating pumps. In rotary pumps, fluid pumping is achieved by rotary motions. Centrifugal pump is a type of rotary pump. Centrifugal pump consists of an impeller, rotation of which causes energy to be transferred to the fluid & thus pumping is achieved .
      Hope its clear. Any doubts are welcome. 🙂

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