dear sir
we already buy a submersible pump with flow rate = 50 m3/h and head =20m
and for some changes in site condition we forced to operate this pump in a different conditions
the new head needed = 10m only
what is the most common method to reduce the head and making the pump to operates in its operating region
thanks a lot
You may want to talk with the manufacturer to trade in the pump for one that matches the system better.
If it is a multi-stage pump, you can remove a stage but this one probably isn't. If it is a single stage, you can trim or replace the impeller. You can install a variable speed drive to slow down the pump. You can throttle a discharge valve to waste head and efficiency. Or you can run the pump inefficiently and replace it when the motor burns up.
but what i knew throttling valve will increase the head not waste it.