F/F G1-1/4" ball check valve

Valve location in the pumping station

The primary purpose of the valve is to prevent pumped sewage from flowing back, so it is installed downstream of the pump on the discharge riser, before the shut-off valves. With this arrangement, if the valve needs to be cleaned or replaced, it is enough to pump out the sewage and close the gate valve. Working on the valve under these conditions will be much easier.

If a ball check valve is installed in a wet well where there is a risk of contact with sewage, it is best to place it above the medium level so that it is not submerged. If the valve frequently comes into contact with the medium because of the small dimensions of the tank, it is much safer to place it below the lowest sewage level, so that it passes through the sewage–air interface as little as possible. In the absence of access to air, any corrosion processes that may occur will last much longer than during continuous wetting and drying.

When two or more pumps operate in a tank, ball check valves not only prevent the pumped liquid from flowing back into the tank, but also prevent liquid pumped by one of the pumps from returning through another. Without check valves, when one pump is operating, sewage returns through the other discharge riser. This causes significant losses of energy and time, as well as very inefficient operation of the pumping unit.