How To Choose The Flow Rate Of A Submersible Sewage Pump

Dec 29, 2025

Flow selection of submersible sewage pump:
1. When there is a drainage adjustment, the flow rate can be selected according to the hourly flow rate of domestic drainage. The flow rate of the drainage pump in the fire elevator water collection tank shall not be less than 10L/s. The head of the submersible sewage pump is determined based on the lifting height and pipeline loss calculation, and then a certain amount of free head is added. The free head should be 0.02-0.03MPa. The flow velocity of the suction and outlet pipes of the submersible sewage pump should not be less than 0.7m/s and should not exceed 2.0m/s. Each domestic drainage collection tank in public buildings should be equipped with a backup pump as a unit, which should be operated interactively during normal times. If there are two or more submersible sewage pumps for flushing the ground in the basement, equipment room, and garage, the use of pumps is not required.
2. When the collection tank cannot be equipped with an accident drainage pipe, the water pump should have uninterrupted power supply;

 

3. When the drainage inlet pipe can be closed, uninterrupted power supply is not required, but an alarm device should be installed.
4. When lifting sewage and wastewater with large impurities, the outlet pipes of submersible sewage pumps in different collection tanks should not be merged and discharged.
5. When lifting general wastewater, the discharge pipes of submersible sewage pumps from different collection tanks can be combined and discharged according to the actual situation. When two or more water pumps share the same outlet pipe, valves and check valves should be installed on the outlet pipe of each water pump. When a single water pump may cause backflow during drainage, a check valve should be installed. It is not allowed to merge the pressure drainage valve with the gravity drainage pipe inside the building for discharge.
6. When the submersible sewage pump is lifted with large debris, it is recommended to have a crushing device; When lifting wastewater containing a high amount of fiber, it is advisable to use a large channel submersible sewage pump.
7. When the motor power is greater than or equal to 7.5kW or the outlet pipe diameter is greater than or equal to DN100, a water pump fixed autotransformer can be used;

 

8. When the power of the submersible sewage pump motor is less than 7.5kW or the outlet pipe diameter is less than DN100, a flexible hose mobile installation can be installed. When using submersible sewage pumps for drainage in sewage collection tanks, a fixed self coupling device should be installed to facilitate pump maintenance. The drainage pump should be able to start and stop automatically and manually on site. Multiple submersible sewage pumps can operate alternately in parallel or in sections.