1. 1 INNOVATION EXPERIENCE SYNERGY COMMITMENT CREATIVITY Air Valves

2. 2 Sources of Air Sources of air in irrigation systems: Air trapped in the system during filling Water contains dissolved air Air drawn into the system by air valves and fittings under vacuum conditions Air intake when water comes from open sources

3. 3 Why Controlling the Air in Systems? High pressure surges Destructive vacuum conditions Pockets of accumulated air will impede hydraulic conductivity Accelerate corrosion of metal parts Reduce pump efficiency Inaccuracies in flow metering Accelerate cavitation damages

4. 4 Air Release & Vacuum Break Valves Kinetic Air Valves

5. 5 Sample system Pump start-up Pressurized air : Risky High pump resistance

6. 6 Risk for “air locks” (for low pressure systems) Sample system Pump start-up

7. 7 Sample system Pump start-up Kinetic air release valve : Allows high air discharge flow: –Large sized orifice Closes drip tight when all air has vented and the system filled with water.

8. 8 During system draining the internal pressure drops and may reach sub- atmospheric levels. Sample system Pipe drainage This might cause the pipe to collapse!

9. 9 Sample system Pipe drainage Kinetic vacuum break valve : Allows high air intake flow: –Large sized orifice Prevents the risk for pipe collapse.

10. 10 Air Release & Vacuum Break Valves Types AV-010 ¾”-2” DAV-P-K 1”-2”

11. 11 Air Release & Vacuum Break Valves Combination Air Valves Automatic Function Included

12. 12 During system operation (water under pressure) air is released and accumulates at local peak points. Sample system Pressurized air release

13. 13 Automatic Air Valves Small orifice Automatic release of entrapped air pockets from pressurized systems SG-10 ½”-1” DAV-P-A ¾”-1”

14. 14 Combination Air Valves Features of the two previous models are incorporated in one single valve body, for safe pipeline filling and draining and for releasing air pockets during system operation DG-10 ¾”-2” DAV-P-2”

15. 15 Combination Air Valves Principle of Operation

16. 16 Location of Air Valves  On rising from pumps, to release and admit air At local peaks in the system At transition points in hydraulic gradient  Before and after steep slopes  Every 500 m along pipeline sections of long uniform slope

17. 17 Thank You