Problems with shielded pumps
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When selecting the shielded pump for our unit to circulate heating oil, the parameters were entered incorrectly; as a result, a pump designed for circulating heating oil was purchased. The on-site outlet valve can only be opened a little, and the current is still quite high. Could everyone help me figure out if I have no choice but to replace the pump?
Look at the specific amount of change in the parameters; if it’s not a very large change, considering machining the impeller might be an option.
I agree with this approach; after reducing the diameter of the impeller, both the rated flow rate and shaft power of the pump will decrease. However, it is necessary to verify the change in the net positive suction head between the cold oil pump and the hot oil pump to determine whether it can be used. It would be best to provide the pump selection parameters and the actual requirements before proceeding. .
Generally, the viscosity of heat transfer oil differs significantly between its cold and hot states; accurate data is necessary before cutting the impeller, as once the cutting is done, this information cannot be retrieved. Pumps that could have been used as backups should not be rendered unusable.
The pump was chosen in such a hasty manner! It is recommended that the original poster provide specific parameters, so that others can help determine what changes need to be made or whether it’s more practical for you to buy a new one.
It’s not easy to do! The impeller cut is insufficient; pumps that use hot heat-transfer oil generally have a separate cooling system – which involves issues such as high viscosity, high specific gravity of the fluid, and cooling water at low temperatures. Professional repair or modification is required. Discussing this issue within this group is not sufficient; it is recommended to contact the manufacturer to find the most cost-effective solution – their proposed solution can also be discussed further.
It is recommended to contact the manufacturer to obtain a new parameter information and consulting solution
I don’t know what parameters were set at that time; the temperature difference was around 100 degrees. Speechless
Also, the graphite bearings of the pumps keep breaking nowadays; could this be related to the low valve opening and high viscosity, as well as poor lubrication and cooling effects for the graphite bearings?
The breakdown of the graphite bearings is related to high viscosity of the coolant at the cold end, poor lubrication as a result, and the absence of a basis for axial force. By checking whether the bearing is damaged at its end face or axially, it is possible to roughly determine whether axial force or lubrication-related failure is the dominant factor. It is recommended that you pay attention to the modification of the rear cooling system and the control of the cooling water volume; as long as the motor can handle it, the temperature in the rear chamber can be kept a bit higher.