Since 1973 we design and build tanks and reservoirs on client specifications. For these tanks we often use flange drain valves because of their big inlet. When it is open it uses 100% of the diameter without any obstacles. An other advantage of this flange drain valve is that it can be easily built at the lowest part of the tank or reservoir. The opening is only 1 cm away from the outside diameter of the valve. It is also a small valve and parts can be easily replaced if necessary.