NPEGValves and Appurtenances

Types of ValvesAir ValvesControl ValvesPressure Relief ValvesPressure Reducing Valves

Air ValvesAir valves are needed to control air in and out of pipe lines.

Types of Air ValvesAir release valve Vacuum relief valveAir and vacuum valveCombination air and vacuum relief valve

Air Release ValveA small orifice, continuous acting valve for air release only.Used at closed summits to prevent formation of air pockets.

Vacuum Relief ValveA large orifice valve for vacuum relief only.

Air and Vacuum ValvesValves with large orifices which allow air to exhaust from the pipeline during filling (not during operation) and allow air to enter the pipeline during emptying.Generally used at either upper or lower ends of pipeline.

Slide GateUsed to let water into gravity pipeline, usually from irrigation canal.Control mechanism is disk or plate sliding over pipe opening.

Check ValvesIn-line back flow prevention valve.Generally used to prevent surge at pumps and to maintain water column in pipelines.Swing checkDouble swing checkRubber flapper check

Check Valves (cont.)Slanting disk checkSilent check (center guided)Automatic control check

Butterfly ValveIn-line distribution valveControl mechanism is a rotating disk inside of valve housing.

Ball ValveIn-line distribution valveControl mechanism is a rotating hollow ball inside of valve housing.

Gate ValveIn-line distribution valveControl mechanism is a sliding plate inside of valve housing.

Globe ValveIn-line distribution valveControl mechanism is plunger inside of valve housing.

Alfalfa ValveOutlet distribution valveControl mechanism is a threaded plate or cap on outside of valve body.Requires hydrant to open and close.

Alfalfa Valve (cont.)

Pressure Relief ValvesA valve used to relieve excess pressure that develops in the pipeline.

Flow MeterIn-line device used to measure flow.In NRCS we generally require meters that give both instantaneous flow rates and cumulative volumes.

Air Vent AssemblyUsed at at high points to provide combination air and vacuum reliefOutlet of vent must be located above the hydraulic grade line for all flows.

Air Vent Assembly (cont.)

Riser AssemblyPipe attached to underground pipeline to deliver water to surface outlets or system valves.A chamber may be required at base for certain installations.

Riser Assembly (cont.)

Drain AssemblyValve and pipe assembly used to empty a pipeline.Generally either gravity or pump out configurations are used.

Drain Assembly (cont.)

Thrust ControlAnchors or thrust blocks used to resist axial thrust in the pipeline at abrupt changes in pipe grade, at changes in pipe alignment, at reductions in pipe diameter, at points of divergence, and at ends of line.

Thrust Control (cont.)

NPRC Project

NPRC Project (cont.)

NPRC Project (cont.)

NPRC Project (cont.)

NPRC Project (cont.)

NPRC Project (cont.) 10 Pressure Reducing Valve

NPRC Project (cont.)

NPRC Project (cont.)

NPRC Project (cont.)

Final Installation

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***Air release valve (AR)Vacuum relief valve (VR)Air and vacuum valve (AV)Combination air and vacuum relief valve (CAV)********************************