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Fumiscope Version 5.0
Operating instructions
Purpose and principles of operation October 2001 Patent Pending The
Fumiscope is a portable instrument which will measure the concentration of
gases in the air. The instrument is calibrated for the measurement of
Methyl Bromide and Vikane gases in the range of concentrations used in
fumigations for insect pest. The display indicates the concentration of
these fumigant gases in dry air to an accuracy of 2 percent of the full
scale reading, in the range from 0 - 2999 oz. per 1000 cu. ft. of Methyl
Bromide or Vikane. ( oz. per 1000 cu. ft. is the same as metric readings
).
The Fumiscope employs a thermal conductivity cell to compare the thermal
conductivity of a mixture of gas and dry air to that of ambient air. This
difference is converted into an electric current which represents the
concentration of the fumigant and is shown on the digital LED display. The
Fumiscope contains a power supply for operation from a 115 volt or 220
volt A. C. line. ( user selectable ) The Fumiscope also contains an
electric air pump and gas flow meter so the gas sample can be drawn
through the T/C cell at a controlled rate.
The Flow rate of the sample stream may be adjusted to a constant value,
regardless of the length of the sample tubing by the flow adjustment knob.
A line filter is placed in the gas sample line to prevent water and dirt
from entering the instrument. The Fumiscope , being a portable instrument,
requires no more than a level place to set the instrument, and a grounded
power source. The power requirement of the Fumiscope is only 200 watts, so
a small 12 volt inverter can be used to increase instrument portability.
The Fumiscope is complete in one case and requires no other auxiliary
equipment.
Inlet - This hose connection is the connection for the sample line to
connect to the instrument through the line filter. A 1/4 " I.D. vinyl
sample line should be used and NO adapters or couplings should be used.
Digital Display - The digital LED display registers the concentration in
oz. per 1000 cu. ft. There is no need to convert readings, however, 1 oz.
= approximately 250 ppm.
Fumigant selector switch - As marked by MeBr and Vikane this switch
changes the display to register the concentration of the selected gas.
Zero adjust knob - This adjustment is used to bring the display to read
Zero after the instrument has warmed up and settled. The instrument should
be set to zero before taking reading and reset after each reading.
Line switch - The line switch is used to turn the instrument on and off.
The switch panal contains the fuses and can be changed to accommodate 120
volt or 220 volt. The instrument can be left on for long periods of time
without harm, in fact, it is beneficial to do so.
Exhaust - An outlet fitting is provided to return exhausted gases back to
the fumigation chamber. This is recommended when the instrument is used in
confined spaces. When used outdoors this may not be necessary, however, it
is recommended the exhaust be directed away from the operator.
Flow Meter - The flow meter indicates the amount of gas sample being drawn
through the unit. The flow meter should always be set to the # 1. This is
the flow rate that is used to calibrate all Fumiscopes. The meter may need
to be adjusted after sample lines are attached and disconnected. The Flow
meter should always read 1.. Occasionally the flow meter ball may stick .
A gentle tap may be necessary to dislodge the ball.
Flow rate adjustment - This knob adjust the flow rate of the flow meter.
The flow rate should ALWAYS read 1.0 .
Operation - When using the Fumiscope to monitor the gas concentration
during a fumigation it is set up in a location outside the area to be
fumigated, but easily accessible to the operator and the line source of
power and light.
The sample tubing used is 1/4" I.D. polyvinyl tubing. Clear tubing is used
so that it may be inspected for dirt and water. If either is present do
NOT use the tubing. The tubing should be clean and dry. Water will damage
the Fumiscope. The sample tubing should be placed at some point in the
fumigation area that the fumigator feels will best represent the whole
fumigation area. Frequently several tubes are used to monitor the gas
concentration various locations within the fumigation area to check the
distribution of the gas.
When all is setup, the Fumiscope should be turned on and allowed to warm
up. This should take about 5 - 10 minutes. It is recommended the Fumiscope
be kept at the same temperature as the fumigated sight. It may take up to
2 hours for the Fumiscope to acclimate if moved from and extreme
temperature. After the display settles the flow meter should be set to the
# 1 and the display should be set to zero. The Fumiscope is now ready to
take readings.
After the gas has been introduced and allowed to reach equilibrium,
connect the sample tube to the filter and allow the pump to draw a sample
into the Fumiscope. This may take a few minutes depending on the length of
the sample tubing. Wait until the instrument reaches it's maximum reading
and does not move for 30 seconds. This is the gas reading. Make sure the
flow meter is still on 1.0 with the tube connected. When the sample tube
is disconnected the instrument should return to zero. Again check the flow
meter ( 1.0 ). If necessary re-zero the instrument before taking
additional readings.
Measuring other gases - The Fumiscope can be calibrated to measure other
gases. Carboxide can be read on the Vikane scale without having the
instrument re -calibrated.
Maintenance - The line filter should be clean and dry. Replace the filter
if the flow rate of 1.0 can not be obtained or moisture is present. This
will extend the life and calibration of the Fumiscope. Avoid letting any
water or dirt to enter the unit. Check the sample tubing to be sure there
is no moisture in the lines. It is advisable to run the Fumiscope before
going to the fumigation job. Let the instrument run for several hours
especially if the unit has not been operated for long periods of time.
Returns - Most damage is done in shipping. We suggest letting a
professional shipping company pack the instrument for return. We MUST HAVE
a return shipping address ( NO P.O. BOXES ) and a name and contact phone
number with area code.
Note: The Fumiscope has been up-dated as of October 2001. The new
instruments no longer require the use of Drierite. Older instruments can
be upgraded to this new patent pending technology. The new model Fumiscope
version 5.0 no longer has a pump switch since there is no need to use
Drierite.
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