US Patent 9920767 Well pump system

Provided is a well pump system that includes a pressure pipe, a rotatable shaft surrounded by a plurality of bearings, a pumping mechanism mounted to the pressure pipe and having a plurality of pump impellers mounted to a second end of the shaft, a rotating mechanism mounted to a first end of the shaft and configured for rotating it within the bearings, thereby causing the pump impellers to move the fluid in the pressure pipe, and at least one non-return valve configured for assuming at least two states including a first, opened state, in which the second pipe chamber is in fluid communication with the first pipe chamber, and a second, closed state, in which the non-return valve obstructs the fluid communication between the first and the second pipe chambers, thereby lubricating them.