Valve assembly location – 3 options makes a difference
Valve assemblies in Romtec Utilities pump stations
Romtec Utilities pumping systems include the complete valve assembly between the pumps and force main. The basic valve assembly includes a check valve and a plug (isolation) valve in the discharge line from each pump. But that’s about it for basics, because each pump station has unique requirements for the valves and where they are located. Depending on various factors, the valve assembly can be located within the wet well, within a separate underground vault or above ground within an enclosure or right out in the open.
In-well valves – For submersible pump stations, reduced cost is an important factor in locating the valve assembly inside the wet well. Less pipe, fewer fittings and no underground vault or above ground enclosure are required, thus reducing cost.
Sufficient space inside the wet well can be a factor; the valves have to fit in the vertical pipe riser. The pre-assembled manifold with valves and piping for one, two or three pump systems can be quickly lowered in place, fitted to the pump discharge elbows and secured with brackets to the wet well.
Consideration must be given to how to maintain valves and pumps when the valves are located inside the wet well. Confined space safety requirements add some maintenance costs, so it is very advantageous to have less frequent valve maintenance. This is partly why pumping systems with in-well valves are often specified for stormwater or clean water rather than municipal wastewater since the hazard of entering the wet well to maintain valves is somewhat lessened. Sewage lift stations with in-well valves are often equipped with grinder or chopper pumps, because there is less potential for damage or clogging of a valve when solids are macerated, thus reducing the potential for valve maintenance inside the wet well.
Underground valve vaults – Most Romtec Utilities pump stations are supplied with an underground valve vault with pre-assembled valves and piping tested to 100 psi. The complete unit is delivered to the project site, positioned near the wet well and connected to the discharge pipes leaving the pumps. Prefabricating the valve assembly inside an underground concrete or fiberglass vault offers many advantages:
1. Protection from freezing and security for equipment
2. Fast installation without expensive field assembly
3. Safe valve operation and maintenance without entering confined space
4. Space in vault for other equipment: emergency pumping port/pig launcher, pressure sensors, etc.
Above-ground valve assemblies – In climates where freezing is not a factor, valves can be located above ground without insulation. In cold weather areas, above-ground valve assemblies must be fitted with insulating jackets.
Romtec Utilities offers a variety of valve assemblies with precast concrete pads ready for placement at the project site. Discharge pipes leaving the wet well are field fitted to the valve assembly. Various kinds of pumping systems often use above-ground valves:
1. Industrial plants frequently prefer the simplified operation and maintenance offered by above-ground valves.
2. Vertical turbine pumps are often fitted with above-ground valves.
3. Emergency pumping systems generally have the valves exposed for quick access.
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