A centrifugal pump is a relatively simple piece of equipment. Transferring electrical energy powering the pump into kinetic energy, an impeller inside the pump spins the liquid inside the pump chamber. As the pump impeller spins the liquid begins to move between the cavities of the impeller towards the outside of the chamber. As this process continues the liquid builds up centrifugal force inside the pump impeller, similar to the force that keeps water in a bucket when it is swung around. This built up force allows liquid exiting the pump to be pressurized. As high-pressure liquid exits the pump, new liquid enters the pump and continues the process.
The casing of a centrifugal pump serves to house the impeller and create a chamber for liquid to be pumped through. The drive pieces of a centrifugal pump also are housed in the casing.
Suction and Discharge Nozzles
Built into the casing itself, the suction and discharge nozzles serve as ports for water to enter and exit from, respectively. Typically, suction nozzles are placed on the end of the pump and discharge nozzles are located on the top.
Seal Chamber and Stuffing Box
Both seal chamber and stuffing box refer to the portion of the pump between the shaft and casing where the sealing mechanism of the pump is housed. Seal chambers utilize a mechanical seal, whereas stuffing boxes achieve the sealing purpose through some form of packing. Regardless of the method used, the chamber is used to prevent liquid from exiting the pump.
The bearing housing is used to enclose and protect the shaft bearings, ensuring proper alignment. The housing will also include some type of method for lubricating the bearings and cooling the pump.
The main moving portion of the centrifugal pump, an impeller is a specially designed component critical for proper functioning of the pump. Depending on the suction type and mechanical construction of the pump, the actual design of the impeller may vary.
The shaft transfers the electrical or mechanical energy powering the pump directly to the impeller. In addition, the shaft is responsible for supporting any other moving parts on the pump. The shaft is responsible for a great deal of both energy transfer and structural support and therefore must be carefully machined.