Shear fracture of the diaphragm in the coupling of the circulating water pump – cause analysis required
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A 10,000-cubic-meter circulating water pump showed a vibration level of 7 mm/s at midnight; the pump was not shut down. During a routine inspection at 3:30 a.m. that same day, fragments were found to have fallen off the coupling diaphragm of the pump. Upon disassembly for inspection at 8:30, it was found that the coupling diaphragm had broken apart, the coupling was damaged, and the shaft was worn. May I ask what caused such severe damage to the couplings? Additionally, our factory has 7 pumps of this type, and 3 of them have deformed or worn oil slinger rings; in some cases, these rings have even broken completely. Is this problem caused by the material quality of the oil slinger rings or by issues related to the operation of the pumps?
The shear fracture of the coupling diaphragm is caused by excessive load, and the excessive load results from shaft wear, as well as vibrations and damaged bearings.
It’s possible that there is a problem with the bearing; the vibration from other components can cause damage to the coupling, resulting in even greater vibration.
May I ask which manufacturer’s pumps are used for the circulating water pump?
First, identify the cause of the excessive vibration in the water pump. Any type of coupling will experience wear when operating under conditions of high vibration for an extended period; in severe cases, this can lead to damage or breakage of the coupling components. Strength checks were conducted before selecting the coupling, and excessive load is not the main reason.