If a waste water tank is being emptied using a powerful shore based pump-out station, it is possible that insufficient air enters through the vent line causing the tank to implode. To prevent this possibility, this Vetus valve type VRF will automatically open with the increasing vacuum, thus letting air into the tank.
Model VRF56 has a free flow area of more than 1100 mm2 and thus fulfils the requirements of the relevant ISO 8099 standard. The hole in the tank must be Ø 56 mm, which is the same size as the hole for a Vetus extraction pipe. This valve is an indispensable safety factor if the vent line has a smaller diameter than Ø 19 mm, or for tanks of more than 400 litres, a vent line less than Ø 38 mm. By using this valve, the necessity to fit a large diameter vent line is avoided, thus saving cost and space whilst still meeting the ISO 8099 standard. This valve is made entirely from synthetic materials and is therefore absolutely corrosion-free.