In particular morphological and operational situations, it may be necessary to use lifting rods over 6 meters long, leading to the exclusion of the traditional wellpoint system. Unlike the latter, the eductor system doesn’t use atmospheric pressure to raise the water and therefore, can theoretically suck water from any depth. It is based on the circulation of pressurized water through an ejector, located at the base of each needle. By accelerating the speed of the flow, the ejector causes a depression in the area behind it, occupied by the wellpoint filter, and therefore the raising of a water flow.
The system is characterized by the following differences compared to the wellpoint system: