43
Enclosed, is a sample of a graph to help in determining the
number and the size of “Guardian” air valves required for
vacuum protection in plastic manifolds at 1.45 psi (0.1 bar)
vacuum pressure.
The slope to be considered is the steepest slope, of any
section of the manifold, from the location of the air valve,
to the lowest point, on either side of the air valve, not
protected by another air valve.
If the Air Intake Flowrate determined by the slope is lower
WKDn WKH RSHUDWinJ ÁRZUDWH DW WKH SDUWiFXODU VHFWiRn RI
WKH PDniIROd XVH WKH RSHUDWinJ ÁRZUDWH WR dHWHUPinH DiU
valve sizing.
For instance, if the manifold is 4” (100mm) in diameter
and the slope is 5% It It P P , the air intake
ÁRZUDWH iV 300 GPM (68 m3 h , according to the graph. If
WKH RSHUDWinJ ÁRZUDWH iV VD\ 370 GPM (90 m3 /h), sizing
VKRXOd EH dHWHUPinHd E\ WKH RSHUDWinJ ÁRZUDWH. $FFRUdinJ
WR WKH ÁRZUDWH dHWHUPinHd E\ WKH VORSH *30
m3/h) RnH 1 in. ´GXDUdiDnµ ZRXOd EH VXIÀFiHnW. %XW DV FDn
EH VHHn IURP WKH JUDSK DW 370 GPM (90 m3/h ) operating
ÁRZUDWH RnH 2 in. ´GXDUdiDnµ iV UHTXiUHd Dnd WKiV iV WKH DiU
valve that should be mounted.
The graphs’ plot areas are color coded according to the
number and sizes of “Guardians” required, to make the
graphs easier to read. ■
'riSSing 6ysteP Zith 2RYaOҋs &RntrRO 9aOYes and $ 5 , *uardian
$ir 9aOYes in the 6nRZ
'riSSing 6ysteP Zith
$ 5 , $9 '7 $ir 9aOYes
A.R.I. & Ooval are happy to have contributed to the
50 years of success in drip irrigation
We congratulate the Israeli drip irrigation industry
for helping the world meet the challenges of
shortages in food and water.