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Weather Conditions:
Radiant energy from the sun has a far greater
impact on foam life than air temperature. In the
absence of clouds, the surface temperature of bare
ground rises rapidly under direct sunlight,
particularly on dark soils where soil temperature
can approach 550C on a sunny day of 250C air
temperature. Foam blobs falling on bare ground
under these conditions may last less than 20
minutes. Under cloudy conditions the soil
temperature will be like that of the air and foam
blobs will generally last 30 minutes or longer,
depending on the actual temperature. Foam falling
on green vegetation will also last appreciably
longer. Under high temperatures the life of foam
blobs can be extended by increasing the amount of
concentrate added to the tank by approximately
50%.
If the air temperature rapidly falls towards 50C, as
can happen at winter sunset, the volume and
quality of foam may deteriorate noticeably. Under
such conditions it is recommended that the
temperature in the foam tank is raised by adding
concentrate which has been diluted with warm
water.
Dry, windy conditions may require an increased
strength of concentrate to keep the foam on the
ground. The amount of concentrate added can be
increased up to double the normal rate if necessary.
When using increased strength solutions, if the
discharge of foam is slower than required because
it is too thick then dilute the mix by adding water.
Storage of Diluted Solution and Concentrate
Diluted foam solutions tend to deteriorate
considerably if stored in the marker tank for more
than two days, resulting in reduced foam volume
and quality. If the solution has been in the tank for
more than 24 hours, it is recommended that it be
drained and replaced with a fresh mix.
Store concentrate in its original container with the
lid securely closed in a well ventilated, cool area.
Concentrate can tend to age when stored for longer
than 6 months and it is advisable to thoroughly stir
and agitate older concentrate before use.
Principal of Operation
Air is pumped from the electric diaphragm
compressor through a hose fitted with a non-return
valve to the bottom of the foam tank.
As the air bubbles through the mixture of water and
foam concentrate it produces foam. The pressure
produced by the entering air forces the foam out
the top of the tank and along the hose to the foam
dropper at the end of the spray boom.
Operation:
Unscrew the foam hose from the top of the tank.
Take care that any built-up pressure in the tank is
released slowly first. Fill to approximately 3/4
capacity with clean water then add foam
concentrate at the recommended rate. Completely
fill the tank with water and refit the foam hose. To
thoroughly mix the solution and avoid creating
excess foam in the tank whilst adding water, insert
the filling hose below the water surface and use a
gentle flow.
Refer to the General Considerations section for
advice on water quality and foam concentrate
dilution rates.
To start foam generation, turn the compressor on
from the control switch and allow enough time for
foam to reach the boom dropper before
commencing spraying. Once the system has been
primed, foam generation can be stopped and
started by operating the control switch.
An adjustable bleed off tap is fitted and can be used
to reduce the rate of foam production. Operating
the tap reduces airflow to the tank and consequent
foam production.
Sometimes a foam marker may “blow out” due to
excess air escaping through the foam. To correct
this problem, reduce the concentration of foam
concentrate in the mixture by adding more water.
