Function of the return line in a centrifugal pump
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What is the purpose of the return line in a centrifugal pump? Is it necessary to open the manual valve on the return line before starting the pump?
Prevent pressure buildup at the outlet from damaging the equipment. It can also serve to regulate flow at the same time.
Agree with the opinion above. The manual valve on the return line must not be opened when starting the pump, as this can cause excessive current to flow through the pump at the moment it starts, potentially damaging the motor. Unless the high-pressure pump has special requirements.
It is used rarely under normal circumstances. It is all regulated directly through the outlet valve; I have seen this valve used for regulation in purification workshops in actual operations before. But it is rarely used in reality.
It can be used right after testing the pump! Adjusting the flow rate is also an option, but it’s used less often. The return pipeline is the same as the main pipeline! Close before starting the pump!
The return line is generally used during pump testing; at that time the system flow path isn’t yet established – it’s just a way to test the pump to see if its performance is normal. Further actions are taken only after the pump is working properly, and it’s not needed during normal operation
Sometimes, such a large volume isn’t required from a technical standpoint, but the pump needs to operate at a certain current level to function properly, and this can be adjusted using a return valve.
You mean the pipeline with the minimum flow rate, right? It can’t be compared to the return pipeline.
Generally, backflow valves must be installed on high-pressure pumps; pumps such as those used for high-pressure ash water in coal chemical industries and condensate pumps must all be operated in accordance with the relevant procedures. . . . . . . . . . . . .
Generally, high-pressure centrifugal pumps are equipped with a minimum backflow setting, especially multi-stage pumps, which require this setting to be activated before starting. When the pump’s operating flow rate is below 20% of its rated flow rate, a radial thrust in the vertical axis direction is generated. Moreover, since the pump operates at reduced efficiency, the liquid temperature at the inlet increases, leading to a rise in vapor pressure and an increased risk of cavitation. Generally, flow control orifice plates are installed at the minimum backflow of multi-stage pumps.