Valves in action -
Bleeding and venting valve EB 3.51
Bleeding and venting valves as overflow protection in artesian wells

The Department of Public Works in a large city in southwestern Germany has part of the necessary ground water pumped from artesian wells. This type of well may only be used in areas that are lower than the surrounding ground, for example valley basins. The location of an artesian well also requires an impermeable stratum above the rock layer that contains the ground water. The artesian well is drilled into the basin below the ground water table. The replenishing ground water from the hillsides generates a hydrostatic pressure onto the valley-sided ground water. Hence the water rises through the well shaft without requiring further auxiliary tools. Consequently, only the pressure from the banked-up water will be used for conveying the ground water upwards.