Double vacuum for wellpoint dewatering
Dewatering applicatins according to the Wellpoint System
In dewatering jobs according to the wellpoint system, it is typical that the water level is higher at the beginning and decreases after some time. After the groundwater level is lowered, the so-called steady state occurs, which is described as follows:
The steady state is the somewhat stationary state of a groundwater flow over the duration of the measure, within the lowered area. This means that the volume of water pumped is completely replaced per unit of time by groundwater flowing in from further outside, and thus the subsidence area does not expand significantly further.
In this condition, the suction lines of the dewatering system are filled with an air-water mixture consisting of air. Therefore, it is particularly important to be able to evacuate the accumulating air volumes in addition to sufficiently dimensioned suction pipes. At the later stage of lowering the groundwater level, the air capacity, i.e. the ability to pump a large quantity of air, comes to the foreground for this reason. Based on this knowledge, HÜDIG has developed the HC488 and HC487 series, each of which is equipped with two vacuum pumps and a total pumping capacity of 200m³/h. This makes it possible to evacuate even larger volumes of water. In this way, even larger dewatering projects can be operated with only one vacuum unit - and with a particularly high energy efficiency. This statement is explained by the control for the individual aggregate components water and vacuum pumps. These switch on or off automatically, depending on the operating conditions.
Note: For smaller groundwater lowering projects, smaller units (each equipped with a water pump and an air pump) are also available.