Air Release Valve
Air release valves (also called air relief valves) are used to withdraw air or other gasses from a pump station’s force main. Gas can collect at any high point in the force main, restricting the pipe at these points and causing the fluid to be partially blocked. This causes the pumps to work harder to move the fluid. If a force main slopes down from its elevation at the valve vault, an air release valve (ARV) will be required at the force main (downstream) end of the valve assembly.
An automatic ARV releases gas automatically. A manual ARV must be opened manually. The valve is plumbed into the wet well to capture any fluid present in the released gas.
Bypass Pumping Port
A pump station’s bypass pumping port provides the means to connect a temporary pump between the wet well and the force main, bypassing the station’s pumps and valves. This could be necessary in the event of a major power outage or clog that could not be overcome using the normal redundant capabilities of the station. A bypass pumping port is also useful during certain maintenance procedures, so the station can continue operation while pumps, valves, controls or other equipment are temporarily disconnected.
The bypass pumping port is usually located at the force main (downstream) end of the valve assembly. When in use, the station’s isolation valves are closed to prevent fluid from running back into the wet well, then the discharge hose from a temporary portable pump is connected to the bypass pumping port, and the pump’s suction hose is lowered into the wet well. This enables the temporary pump to empty the wet well into the force main.
Pig Launcher
A “pig” is a device that is inserted into the force main exiting a wastewater pump station to clean the force main and remove obstructions. The pig, which fits the inside diameter of the force main, spins as it is pushed through the force main with water pressure.
A pig launcher, located at the force main (downstream) end of the valve assembly, has a removable cap that provides access to the force main. The pig is fitted into the force main, the cap closed and a high-pressure hose is connected to the launcher. The water pressure drives the pig up the pipe, spinning as it goes. This action scours the inside of the force main, removing grease and other solids that restrict the normal flow within the pipe.