What are Vacuum Wellpoints?
A Vacuum wellpoint system is a complete dewatering system that consists of a wellpoint pump, a vacuum header, and a number of wellpoint connected to the vacuum header. The wellpoint pump is used to apply a vacuum to a series of wellpoint via a vacuum header. The wellpoint is a two to three-inch diameter self-contained vacuum well composed of casing, screen drawdown tube and check valve installed into a predrilled hole or jetted into the ground, usually no deeper than 25 to 30 feet. The vacuum header pipe provides groundwater removal by suction left of a series of wellpoints or dewatering Wells. Finally, dewatering wells are assisted by vacuum in order to improve their ability to remove entrained water, particularly for soils with fine grains.
Vacuum wellpoints are well suited for a wide range of soil permeability’s (fine to coarse grained soils). They are generally 15 to 25 feet deep and constrained by the limits of the vacuum to pull water out of the ground. They typically have a 3-foot length of slotted well screen at the bottom and are most often spaced from 2 to 10 feet on center, depending on the soils type.