An eductor is a form of jet pump used in the dewatering process. It takes advantage of the nature of fluid dynamics to extract water from excavation sites that may be below the groundwater table.
Eductor systems are effective in trenchless construction operations in areas where soils are less permeable.
Trenchlesspedia Explains Eductor
An understanding of fluid flow is of great benefit when attempting to clear water from excavation sites. It is of particular interest when implementing methods of dewatering such as those that employ eductor systems. Central to the theory of fluid dynamics is the work of the Swiss mathematician Daniel Bernoulli in the 1700s. Bernoulli determined that certain factors in fluid flow, including pressure and velocity, are constants that can be calculated with some precision.
The concept of an eductor, which comes from a Latin word meaning “to lead out,” is to cause groundwater to join a flow of pressurized water as it moves into and back out of the excavation site. Especially when using something called a venturi, which is a section of hose or pipe that is narrower than the others, an eductor system transforms pressure to velocity, essentially unleashing energy through controlled fluid flow. It involves creating a vacuum that sucks the groundwater, which is at a lower pressure, up to the surface.