Air Release
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Air/Vacuum Valves Air and vacuum control is essential to the safety, longevity, efficiency, and performance of an irrigation system. Air must be allowed to exit pipelines 1) upon startup to prevent water hammer, 2) during normal operation to prevent the development of air pockets, and 3) air must be allowed to enter pipelines and laterals at shut down to prevent vacuum suction. Various types of valves and vents are available to perform these functions. Application: Removal of Air from Pipelines • Avoid Water Hammer: Air must be allowed to escape pipelines at the same rate as water enters the pipeline during system startup to avoid dangerous water hammer from occurring. • Remove entrained or dissolved air: Air that has accumulated at high points during system operation must be allowed to escape to avoid air pockets which restrict the flow of water and can cause water hammer. Allow the Entry of Air into Pipelines • Prevent Vacuum Suction in Pipelines: Air must be allowed to re-enter main and submain pipelines as water drains during system shut down to prevent negative suction from occurring and potential collapse of the pipelines. • Prevent Vacuum Suction in Laterals: Laterals which are buried or submerged in water may ingest dirty water and/or soil through the emitters as a result of vacuum suction if air is not allowed to enter the laterals during system shut-down and drainage.

Continuous Acting Air Release Valves 1" & 2" Combination Large Volume Air Relief and Continuous Acting Air Release & Vacuum Relief Valve • Install at highest points on filter and pump stations to provide both instantaneous and continuous air relief • Install on main manifolds every 1000 feet to introduce air into the irrigation system at shutdown to prevent pipe collapse • Install at highest point of slope to provide vacuum relief at system shutdown

1" & 2" Air Release & Vacuum Relief Valves • Install on manifolds to exhaust air at system start-up • Install on manifolds to introduce air into the pipeline and provide vacuum relief after system shutdown • Install downstream of valves to introduce air into the pipeline and provide vacuum relief after valve shutdown • Install at highest point of slope to introduce air into the pipeline and provide vacuum relief after valve shutdown

Application: The Aluminum Air Vent series can be used on gravity or higher pressure systems, allowing for operation up to 150 psi on the 2" model and 100 psi on 3" and 4" models. The float and precision O-Ring provide a tight seal at a very low pressure, while the strong aluminum alloy body and full baffle allow for maximum vent capacity without premature closing. Features and Benefits: • Cast Aluminum body combines lightweight strength and corrosion resistance • Synthetic rubber O-ring assures a positive seal even with low head applications • Simple design ensures trouble-free...

Application: The 1 /2" Air & Vacuum Relief Valve (ARV) is specifically designed to prevent soil ingestion of emitters from back siphoning. Air Intake Flow Chart 1/2" Vacuum Breaker (ARV) - 0.4 - 0.3 <1) • Large Air Passage • High resistance to chemicals • Smooth, reliable operation • Easy to handle and maintain • Plastic construction • Buna-N Seal Application: The 1" Plastic Air Vent provides instant air and vacuum relief. The brightly colored cap allows for easy visibility and is removable for easy maintenance.

Installation* The simplest method for selecting the proper size of air/vacuum relief valves is called the "four-to-one" rule. This rule specifies that the clear opening diameter of the air/vacuum relief valve be no less than 1/4 the inner diameter of the pipe. Thus, for an 8-inch pipe, the air/vacuum relief valve should have a clear opening diameter of no less than 2 inches.** Air vents (vacuum relief) should be installed downstream of all shut-off valves. Air vents (vacuum relief) should ideally be installed at or near all high points in manifolds (both inlet and flushing manifolds). Air...