End suction horizontal centrifugal pumps
The end suction horizontal centrifugal pump is highly efficient and is the most commonly used type of pump. Before start-up, the pump and suction pipe must be completely filled with water. The rotating impeller draws in liquid and builds up pressure. The impeller dimensions and speed determine the flow rate and head.
A number of centrifugal pump types are manufactured to a specific standard. Even so, one brand is not necessarily comparable to another. The comparison only holds true where pump specifications are more or less the same. Other selection criteria are often underestimated and overlooked in terms of their importance. However, these criteria make the crucial difference between a good and a poor pump selection. IB-Pompen makes the difference.
How a centrifugal pump works
A centrifugal pump consists of a pump casing containing one or more impellers. For the pump to operate, the casing must be filled with liquid at start-up. As the impeller rotates, the liquid is flung towards the outer circumference, creating a low pressure at the centre of the impeller. This causes liquid to be drawn in at this point. The liquid velocity is highest at the outer circumference of the impeller. In the pump casing, this velocity is then converted into pressure.
The wider the impeller, the more liquid can be pumped and the higher the capacity. The larger the impeller diameter, the greater the head (pressure) that can be generated. The impeller’s rotational speed has a direct influence on both the capacity and the head, and also significantly affects the power consumed by the motor. The duty point ultimately reached also depends on the characteristics of the system in which the pump is installed.
Different types of centrifugal pump
Centrifugal pumps are available in end suction and self-priming designs. The casing of a centrifugal pump must always be filled with liquid for the pump to operate. An end suction centrifugal pump cannot handle any air, or only very little. Both the casing and the entire suction pipe must therefore always be completely filled with liquid.
A self-priming centrifugal pump is usually designed such that the impeller always remains below the liquid level. If air is drawn in from the suction pipe, it mixes with the liquid present in the pump casing. The air then gradually leaves the casing via the discharge side, whilst the impeller continues to create a low pressure.
To prevent excess air from entering the pump, it is important that both the suction and discharge pipes are correctly designed.
