Well Pumps
Well Pumps are commonly used to extract water from water wells. The main pump, often Centrifugal Pumps, are powered and installed at ground level. Its discharge is split, with the greater part of the flow leaving the system, while a portion of the flow is returned to the well pump installed below ground in the well. This recirculated part of the pumped fluid is used to power the jet. At the well pump, the high-energy, low-mass returned flow drives more fluid from the well, becoming a low-energy, high-mass flow which is then piped to the inlet of the main pump.
Types
Shallow well pumps
Shallow well pumps are those in which the jet assembly is attached directly to the main pump and are limited to a depth of approximately 5-8m to prevent cavitation.
Deep well pumps
Deep well pumps are those in which the jet is located at the bottom of the well. The maximum depth for deep well pumps is determined by the inside diameter of and the velocity through the jet. The major advantage of well pumps for deep well installations is the ability to situate all mechanical parts at the ground surface for easy maintenance. The advent of the electrical submersible pump has partly replaced the need for jet type well pumps, except for driven point wells or surface water intakes.