Fan Types in Centrifugal Pumps
The main function of the fan is to transfer the mechanical energy coming from the engine through the shaft to the fluid passing through it and to provide a certain pressure and flow to the liquid or gas.
Considering the variety of raw materials used in production, it is essential to transfer liquids with very different properties. As these liquids and their properties change, the type of fan used in the pump must also change. For example, the fans of a mud pump, an irrigation pump and a wastewater pump used in a mine must be different from each other. Each fan type has certain advantages and disadvantages depending on its intended use.
Open Fan
As seen in the figure, the open fan is a type of fan that consists of blades coming at an angle from a certain center and has no restrictions at the front and a semi-opening at the back. It is generally used to transfer wastewater containing solid particles or fluids containing food made of stainless material.
Since its solid part permeability is high, it is ideal for processes with a risk of clogging. However, since the fluid is not compressed by the fan, pump efficiency is unfortunately low.
Close Fan
Close Fan, It is closed on both the front and back surfaces in order to fully pressurize the fluid. In this way, the fluid entering the fan is compressed by the front and rear covers, and with the rotation movement of the fan, energy flow directly from the blades to the fluid. It is used in many applications and is the main type of fan used unless there is a special situation. Although it is possible to use different types of fluids by enlarging the fan or changing the blade opening, there is a risk of clogging when there are particles in the fluid and cleaning is very difficult.
Half Open Fan
This fan type is actually the type where the back side of the open fan we mentioned above is completely closed. In other words, while the rear surface of the fan prevents the escape of fluid, there is no restriction on the front. Semi-open fan is preferred in fluids where solid particles may occasionally occur but are smaller in size and less frequent. Although it is more efficient than the open fan, it is not possible to reach the efficiency of the closed fan.
These three fan groups we mentioned constitute the basic structure and logic. Apart from these, there are a wide variety of fan types developed by manufacturers according to the processes they specialize in, some examples of which are as follows. The important point at this point is to determine the type of fan that is most suitable for the process to be used.
Source: KSB Global
