Title: 320- Tilbakeslagsventil.pdf
3 0 / 8 0 - K UBack-siphoning Back-siphoning When the pressure in the water supply network When the pressure in the water supply network falls, the second check valve closes against the falls, the second check valve closes against the seat. The first check valve closes against the seat. The first check valve closes against the diaphragm, the discharge opening opens to the diaphragm, the discharge opening opens to the intermediate zone, once enough overpressure is intermediate zone, once enough overpressure is created. This creates an atmospheric created. This creates an atmospheric "interference" between the water supply network "interference" between the water supply network and the contaminated water downstream. If the and the contaminated water downstream. If the check valve is contaminated, seepage is check valve is contaminated, seepage is discharged via the opening. This prevents discharged via the opening. This prevents contamination of the drinking water. contamination of the drinking water.