Refraction 7
DG711 and DG511 Pipe Laser User Guide 69
11 If the beam still can not be
controlled, have your backhoe
excavate five buckets full and then
one or two empty buckets as if it
were bailing water. The blower is
pushing heavy fumes in the pipe
that can not get out of the trench
without someone’s help. Cast the
empty bucket on the low side of the
surface or on the downwind side of
the cut.
12 Another solution is to have a
Homelite III-B blower (or
equivalent) at the cut end of the
trench pulling these fumes from the
cut as the electric blower blows
them out of the pipe. This method
does not tie up production and gets
the job done more efficiently.
13 In summary, if all of the above
fail to solve this problem, use the
laser in an over-the-top setup.
Model 929 Blower Operating Instructions 7.1
1Use a separate 12-volt
automotive battery to power the
blower.
2Point the nozzle into the pipe to
create a corkscrew effect. This is
the most effective way to create
temperature stabilization.
3Ensure the air intake is not
blocked and the 929 is not set in
water. The support handle/cord
wrap bracket is on the opposite
side of the air intake. This handle
can hook over a manhole step to
keep the unit out of water in the
pipe.