Vales

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Vales

  1. 1. 4/1/2011 Irrigation ValvesValves used either to release water into: a.distribution lines b.sprinkler headsValves can be: a.manually opened b.opened by remote c.automatic controllers d.auto shut down with pressure differentials (pumps)Opening and closing of remote valves eitherthe diaphragm type or piston type• Most used are diaphragm type because lessparts to wear• Piston types have valves and rings that needperiodic servicingElectric valves electric diaphragm valve•24 -Volt valves open and close with solenoid.• Most electric valves in closed position withpower off • When 24 volt currant. solenoid draws plunger in and pressure of water pushes diaphragm upward •Power off – pressure holds diaphragm closed Note* severed wire valve will be closedElectric valves either in line or attached tosprinklers (valve in head) 1
  2. 2. 4/1/2011 Turf Irrigation Manual By: Richard Choate http://www.superiorcontrolsco.com/product_main.html Electric valves either in line or attached to sp Turf Irrigation Manual By: Richard ChoateTips for installing electric valves1.Install a shut off valve to isolate & make repairs easier2.Do not cram valves / shut offs into service box. (Use the correct size of box)3.Place valve boxes on gravel base4.Leave at least 12 inches extra of wire. (do this for valve in head as well)5.Use Teflon tape for connections, not pipe dope6.Install valves straight for ease of service7.Use PVC Primer on welds 2
  3. 3. 4/1/2011 TYPES OF VALVES1. Globe valves Turf Irrigation Manual By: Richard ChoateHigh resistance to water flow due to small openings andsharp turns.2. Gate Valve• From outside globe and gate valves look similar.• Gate lifts and lowers as you turn• To close turn to right to open turn to left• Fully open straight run and least resistance Turf Irrigation Manual By: Richard Choate3. Ball valves• Little resistance when fully open• Works by lever action.• Place with handle perpendicular to ground for better leverage Turf Irrigation Manual By: Richard Choate 3
  4. 4. 4/1/20114.Quick coupler valves Turf Irrigation Manual By: Richard Choate5.Check Valves• Placement with relation to flow extremely important in installation• Allow flow only in one direction• Discharge side of the pump (on centrifugal pumps)Check Valves continued:TWO TYPES a. Spring loaded that pushed out of the way for flow and spring closed do to back pressure. Turf Irrigation Manual By: Richard Choate 4
  5. 5. 4/1/2011Check Valves continued: b. Wafer Swing Check Valve Turf Irrigation Manual By: Richard Choate6.Foot valves• Important with pumping systems• Used on non-submersible pumps (i.e. jet pumps)• Shut down pump foot valve closes and will not let water drain out of system. It keeps the pump primed Turf Irrigation Manual By: Richard Choate 5
  6. 6. 4/1/20117.Atmospheric Vacuum Breakers•Stops siphon action•Placed right after supply line shut off valve•Check valve that will seal when water shut down orflow reversed. Back flow directed to atmosphere Turf Irrigation Manual By: Richard Choate•Mandatory when protecting domestic water•Minimum 6-12” above highest sprinkler Turf Irrigation Manual By: Richard Choate8. Air Gap Turf Irrigation Manual By: Richard Choate 6
  7. 7. 4/1/20119. Backflow prevention valvesTwo types of back flowa. Back siphon – when water travels from area of high pressure to low pressure. Example: Example: City pressure drops due to high demand, i.e. fire hydrants turned on.Backflow prevention valves continued:b. When elevation or other causes result in a higher pressure on the irrigation system than on the supply system. For Example: If system is off and there is an elevation change from the system to the backflow then there is a back pressure on the backflow valve. The degree of pressure is dependent on the elevation System on System off Back Flow 7
  8. 8. 4/1/2011Backflow prevention valves continued:Placed right after source shut off:i.e. city shut off. > meter > backflow preventiondevice Reasons •No water back into city water •Sprinklers are ground level or below, it is conceivable that ground water could enter back into sprinklers. •Often times irrigation systems can be fitted with fertilizers or pesticide injectorsBackflow prevention valves continued:• Many types some, or most, for largeirrigation systems• Often they consist of two spring loadedvalves that are in line.• When water shuts down flow stops and thereis a “dump” after the first valve that water willexit in backflow.• Backflow devices are the law for hose bibs.(filling spray tanks)!Backflow prevention valves continued: Turf Irrigation Manual By: Richard Choate Spring loaded valves 8
  9. 9. 4/1/2011Backflow prevention valves continued:• Devices more complicated on automatic systemsunder constant pressure.• Backflow devices are the law when connected tomunicipalities.• Used when municipal or city water is used in anirrigation system• Water departments will specify device and will test(at a minimum) annually to assure proper operation. 9

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