Above-Ground Valve/Meter Assemblies
Above-Ground Valve/Meter Assemblies
Above-Ground Valve & Mechanical Assembly
Yes, having a check valve on each discharge line is very important. The check valves keep the liquid that is being pumped from flowing back into the wet well through the pumps. The check valve can either be installed in the wet well or in a separate vault.
Yes, Romtec Utilities offers a wide variety of different option for flow metering of any water type. Romtec Utilities can provide physical flow metering in a precast concrete meter vault, which senses and records the actual water passing through the discharge piping. Romtec Utilities can also offer a control panel that can provide calculated flow rates, which uses the specified pumping rate in gallons per minute and the time of operation to calculate the flow.
Restrained flange couplers help connect flanged end pipes to plain end pipes. One end bolts to the flanged pipe and the other has bolts that lock down around the outside of the plain end pipe holding it in place (see figure below). One of the advantages to this kind of adapter is that it can connect a wide variety of pipe types where both pipes are the same material or different materials. You can mix pipe materials as long as the flanged end can bolt/fit onto the specified flanged pipe and the other receiving end is sized for the correct pipe material diameter. For example, it is quite common to use a pvc adapter to connect a plain end pvc pipe to a flanged pump elbow (often cast iron or other metals). The biggest advantage is often the flexibility of the connection. The restrained flange coupler offers a little movement for pipe alignments so small errors in alignment can be compensated for. This make pipe installation much easier especially in applications like wet well discharge piping where having a little “wiggle” room in to install the pipes (often above 10 ft in length) is almost necessary.
Sealed and non-sealed plug valves each accomplish the same function in the system, but site layout and price can determine which type is used in the design. Site layout determines whether a valve vault is even a possibility. Valve vaults take up space, and some project sites do not allow for much construction outside the wet well. When a valve vault is not feasible, plug valves are located in the ground outside of the wet well, and are accessible through valve boxes, aka cans. These valve boxes allow for the operators to access the sealed valves and to manually change the valve parameters. While sealed valves are more expensive than non-sealed valves, the cost of a valve vault is far more expensive than using sealed valves with cans. When a valve vault is part of the design, non-sealed plug valves can be used. These valves are protected within the valve vault and are completely accessible to the lift station operators. However, some customers still want sealed service plug valves within a valve vault in case the vault were to flood.
A pumping port provides a tie-in to the force main in case there is a problem with the lift station that causes the wet well to fill to capacity. This allows for an emergency mobile pumping system to drop in to the wet well and pump the inflow to the existing force main. The pumping port is located downstream of the check valve in either a valve vault or a separate enclosure. The check valve prevents the water from reentering the wet well. This method is an affordable way to prevent overflow in emergency scenarios; otherwise, the inflow would need to be pumped to trucks and hauled to a discharge point or treatment. Romtec Utilities always suggests designing a pumping port into a lift station package.
Air release valves (ARVs) are used to help resolve air entrapment issues. ARVs are typically located at high point elevations in force mains. The ARV released any entrapped air caught at the high point of the system (see image below 1). This air can come from pressure changes, the pumps, through any openings, and/or through fittings. There is air trapped at high point elevations because air is lighter then water and there is nothing forcing it down the pipe system. If this air is left in the system it can reduce efficiency or can cause water hammering. In more extreme cases it can cause a total “air lock” within the system. ARVs are also used in a lift station design when the piping leaving the system has a high point. For example, the force main may be slightly down hill or it could be an industrial site where the piping comes out the top but then descends again to be underground (see picture below). This is typically done so that the valves and pressure gauges can be above ground to help aid in maintenance. ARVs can also be placed inside a valve vault of the lift station for easy access for maintenance. Without the ARV, cavitation can occur along with the other problem listed above causing damage to the lift station and pumps.