How is the stage calculated in a submersible pump?
“A submersible pump suitable for a 6” (inch) bore well, will have outer diameter of the main pump body (motor + pump) at about 5 and odd inches to allow necessary margin of gap for lowering and rotation of the pump.
The outer diameter of a pump suitable for a 6” bore is already fixed by the pump manufacturers. Usually the diameter of the rising pipe which brings water to the surface for a 10 HP pump is to the order of 2” – 3” depending on discharge.
The pump itself is a multi-stage unit with the number of stages being determined by the operating requirements. Each stage includes an impeller and diffuser.
Each impeller is coupled to the rotating shaft and accelerates fluid from near the shaft radially outward. The fluid then enters a non-rotating diffuser, which is not coupled to the shaft and contains vanes that direct fluid back toward the shaft.” For more info, check out @ tftpumps.com.