MIL-HDBK-1164
Table 4
Eductor Submergence Required for Various Well Depths
Depth of Well
Submergence of Eductor
(feet)
(m)
(percent of well depth)
10-50
(3.0-15.2)
70-66
51-100
(15.5-30.5)
65-55
101-200
(30.8-61.0)
54-50
201-300
(61.3-91.4)
49-43
301-400
(91.7-121.9)
42-40
401-500
(122.2-152.4)
39-33
(2)
Cap the 4-inch (100-mm) eduction line with a tapped pipe
plug through which the air line runs. Connect the air pipe by means of an air hose (or
non-rigid system) to an air compressor having a minimum capacity of 110 cubic feet per
minute (cfm) or 50 liters per second (Lps).
(3)
With the eduction valve open, build up the air pressure until
the water is discharged and pressure reaches a constant value. Pump the water until it
runs clear.
(4)
Release the air pressure, close the 4-inch discharge valve,
and apply air until static pressure is reached. At this point, air escapes from the bottom
of the 4-inch eduction pipe and causes both air and water to surge through the screen
and create movement in the sand and gravel.
(5)
Open the 4-inch (100-mm) valve and allow the air-lift to
pump out the loosened sand and silt.
(6)
When the water is clear, repeat steps (4) and (5) above.
Faster results can be obtained if water can be pumped into the well casing while the air
is being added (step (4) above).
(7)
Check results after each series of operations. An increase
in pumping pressure on the gage indicates increasing inflow into the well and less
drawdown.
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