Selecting The Appropriate Model Of A Submersible Pump

1. The changes in the flow rate and head of the submersible pump directly affect the economic efficiency and operational reliability of its use.
Different specifications of submersible pumps have different application scopes. The flow rate and head specified on the nameplate of any submersible pump are the rated operating points for this pump, and they are generally also the optimal points for the pump's efficiency. During the use of the submersible pump, when the flow rate and head output by the pump change, the efficiency of the pump and the output shaft power of the motor also change accordingly, thereby directly affecting the heating and temperature rise of the stator winding of the motor. This, in turn, has a significant impact on the economic efficiency and operational reliability of the submersible pump's use.
2. The reasonable usage range of submersible pumps
With different structural types of the pumps configured for the submersible pump, the characteristics of the submersible pump also vary. For centrifugal pumps or mixed-flow pumps, when the used head exceeds the rated head, the required shaft power of the pump decreases; when the used head is lower than the rated head, the required shaft power of the pump increases; when the used head is much lower than the rated head, the required shaft power of the pump will increase significantly, at which point the load of the submersible pump increases significantly, the stator current increases, and the stator winding often overheats. If the submersible pump operates for a long time at a low head and high flow rate, the stator winding overheats severely and often burns out the motor. For axial-flow pumps, the characteristics are exactly the opposite: when the used head is lower than the rated head, the required shaft power of the pump decreases; when the used head exceeds the rated head, the required shaft power of the pump increases; when the used head is much higher than the rated head, the required shaft power of the pump will increase significantly, at which point the stator winding of the submersible pump will overheat. If the axial-flow submersible pump operates for a long time at a high head, the stator winding overheats severely and often burns out the motor. Submersible pumps can generally operate normally within a range of 0.7 - 1.2 times the rated flow rate (sewage and waste water submersible pumps can operate normally within a range of 0.7 - 1.3 times the rated flow rate). Beyond this range, overload may occur, so users must consider the appropriate usage range when choosing and using submersible pumps. Especially for multi-stage well-used submersible pumps, more attention should be paid: for high-head submersible pumps, they should not be used at too low a head to avoid wasting electricity and possibly damaging the submersible pump.
3. Select the appropriate specifications of the submersible pump reasonably
When purchasing a submersible pump, users should choose the specifications that are as close as possible to the required head and flow rate. In particular, the head of the selected submersible pump should not be too high (or too low) to avoid wasting electrical energy and causing adverse effects on the pump when it is used under such low (or high) head conditions.