TM 10-6665-297-13&P
3-2
CALIBRATION (continued)
3-2.2
Calibrating a System with Two Detectors per CD800/830 Control Unit. (continued)
4.
Record meter responses to each detector to aid in evaluating future performances of the
detectors.
3-2.3
CALIBRATING A SYSTEM FOR VOLATILE HYDROCARBONS WITH FLASH POINTS BELOW
70F. The following materials are required to calibrate a detector/module system for response to
volatile liquid vapors:
Graduated pipette, 0-1 ml (lcc).
One-gallon jug with cap
Piece of aluminum foil
Thermometer
Sample of volatile liquid
Calibrate detector/module system for response to volatile liquid vapors as follows. Before exposing
detector to sample mixture, confirm that meter reads zero with detector sampling fresh air. Adjust
ZERO control R24 of CDS00/830 Systems, or Channel 1 Z1 (R9) and Channel 2 Z2 (R13) of
CD802/832 Systems, if necessary.
1.
Using pipette, drop 0. 2cc of liquid from which vapors are to be detected in a one-gallon jug.
Place aluminum foil on jug to aid in mixing vapor in air.
2.
Cap jug and agitate until liquid has completely evaporated and vapor has diffused.
NOTE: Benzene, toluene, hexane, and xylene may take up to half an hour to
evaporate and diffuse.
3.
Remove cap and place mouth of jug over detector. Invert jug if position of detector permits,
since vapors of all flammable liquids are heavier than air.
4.
Note reading on module indicating meter after 45 seconds. Reading should approximate
percent L. E. L. value for same liquid at temperature of 70°F as listed in Table 3-2. (Heat or
cool vaporizing jug to therometer reading 70° for testing. )
5.
Adjust GAIN potentiometer R10 on control module circuit board to move meter indicator to
read on scale at approximate Table 3-2 value.
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