Valves and Appurtenances NPEG Valves and Appurtenances 1

Types of Valves Air Valves Control Valves Pressure Relief Valves Pressure Reducing Valves

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

Types of Air Valves Air release valve Vacuum relief valve Air and vacuum valve Combination air and vacuum relief valve Air release valve (AR) Vacuum relief valve (VR) Air and vacuum valve (AV) Combination air and vacuum relief valve (CAV)

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

Vacuum Relief Valve A large orifice valve for vacuum relief only.

Air and Vacuum Valves Valves 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 Gate Used to let water into gravity pipeline, usually from irrigation canal. Control mechanism is disk or plate sliding over pipe opening.

Check Valves In-line back flow prevention valve. Swing check In-line back flow prevention valve. Generally used to prevent surge at pumps and to maintain water column in pipelines. Double swing check Rubber flapper check

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

Butterfly Valve In-line distribution valve Control mechanism is a rotating disk inside of valve housing.

Ball Valve In-line distribution valve Control mechanism is a rotating hollow ball inside of valve housing.

Gate Valve In-line distribution valve Control mechanism is a sliding plate inside of valve housing.

Globe Valve In-line distribution valve Control mechanism is plunger inside of valve housing.

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

Alfalfa Valve (cont.)

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

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

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

Air Vent Assembly (cont.)

Riser Assembly Pipe 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 Assembly Valve and pipe assembly used to empty a pipeline. Generally either gravity or pump out configurations are used.

Drain Assembly (cont.)

Thrust Control Anchors 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