HÜDIG - Application of piston pumps
Piston pumps look back on a long history since ancient cultures like the Romans had reciprocating piston pumps to pump water already. In the field of wellpoint dewatering, this type of aggregate has been used since the 1930s. After a long absence due to the displacement of professional vacuum units, piston pumps have experienced a kind of renaissance since the beginning of the new century.
For most applications, our customers rely on the technically superior, low-maintenance and, above all, reliable electrical and diesel units, which are supported by at least one, especially powerful and oil-free vacuum generator. In some cases the use of piston pumps is quite sensible. Piston pumps are particularly suitable in sand-containing soils, for example, in areas which have been repelled by the ocean from sand. The advantage of this is that the continuous pulsation of the flow keeps the wellpoint filter surface clear in fine sanded soils.
However, there are also some disadvantages compared to modern vacuum units. Furthermore, the performance of the piston pumps is limited. The vacuum levels as well as the pressure levels of the currently available units are limited. If the pumping capacity of the piston pump provided is not sufficient, several units must frequently be connected in parallel. A very unpleasant side effect for the one who pays the bill at the end of the day.
The functional principle does not provide for a separation of the water-air mixture within the unit. The aggregates can only promote either water, air or a mixture of both. If a volumetric measurement is required, the extracted air must be separated from the water. If this separation is not carried out, there are errors in the presence of air traps, which will also unnecessarily burden your wallet when water charges are required. Piston pumps are also sensitive to sand-laden conveyance and no vacuum can be adjusted. This is the reason why that more groundwater is produced than necessary.