Is an eccentric reducer suitable for the outlet of a double-suction pump?
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Looking at the discussions, there are considerations regarding the size of the inlet and outlet; if the diameter change is not handled properly, vibration becomes severe. Some also say that there is no cavitation at the outlet. It doesn’t matter what type of flow resistance is used, and there are many reasons for vibration – how can one determine whether it is caused by the elbow fittings?
The installation of eccentric connections with different diameters is fine as per the requirements. Vibration, if it occurs, is usually caused by factors such as the prestress in the connection to the foundation (inadequate bolt tightening), secondary grouting, the position and level of shims, the clearance and alignment between the couplings, damaged bearings, and poor dynamic balance. A key illustrative case: a water pump was vibrating, resulting in consecutive shaft breaks in a short period of time. The reason is that one of the foundation bolts appears to be tightened on the outside, but in reality the screw thread is constrained by the nut, and the pump body is not secured to the foundation; as a result, vibration occurs due to the lack of proper fixation and the absence of prestress. It is also difficult to identify vibrations caused by defects in concealed works such as shims and secondary grouting that were not carried out as required. In many cases, secondary grouting is done by hand rather than using grouting material, or without vibration.