What is the function of Stainless Steel Concentric & Eccentric Reducer? It is used to change the size of the pipe diameter. So what is the use of changing the size of the pipe diameter at the inlet and outlet of the pump? It is mainly to reduce the flow rate of the medium in the pipeline, and reduce the flow rate to reduce the friction of the medium when it flows in the pipeline.

The horizontal eccentric reducer at the inlet of the centrifugal pump is generally arranged at the top flat, but when the reducer is directly connected to the upward elbow, the bottom flat arrangement can be adopted. The reducer should be close to the pump inlet. The reason for the top flat installation is to prevent gas from accumulating in the eccentric reducer and entering the centrifugal pump, causing cavitation damage to the pump. When the inlet of the horizontal suction centrifugal pump is changed, the top flat installation is adopted when the pipeline enters the pump from bottom to top, and the bottom flat installation is adopted when the pipeline enters the pump from top to bottom (top flat installation is also adopted to prevent gas accumulation at the pump mouth). The bottom flat installation is adopted when the medium contains impurities and the suction speed is lower than the impurity sedimentation speed. The principle is not to form air bags.

Regarding the installation of eccentric reducers on the inlet pipe of end-suction centrifugal pumps (i.e., the pump inlet is horizontal), the textbooks on pump piping standards stipulate that the orientation of the eccentric reducer on the horizontal pipe (whether the horizontal part is upward or downward) is determined by whether there are liquid bags or air pockets (two situations):

1. When the medium enters the pump from top to bottom, use a bottom-flat eccentric reducer for installation, and no liquid bags will appear;

2. When the medium enters the pump from bottom to top, use a top-flat eccentric reducer for installation, and no air pockets will appear;

In summary, it is generally "bottom flat for top inlet, top flat for bottom inlet".

To understand the reason, first understand a knowledge point: cavitation phenomenon. Of course, if you are only doing industrial installation, you don't need to know so much, because there are complete and correct installation methods in the manual of each pump manufacturer, and you only need to follow the drawings for construction.