F:\MARKETING\TECHNICAL MANUALS\Air Samplers\DF Battery TECH MANUALS\DF-75 LPM SERIES.doc
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CALIBRATION INSTRUCTIONS
The adaptor secures to the air sampler with a quick connect fitting and to the calibrator with the
attached tubing. During the verification, the adaptor replaces the filter holder.
NOTE:
Be sure to insert the proper filter media into the air sampler adaptor prior to attaching
the adaptor to the air sampler.
Performing the Calibration:
Ensure the air sampler and the calibrator are on a level surface
Ensure the Calibrator has warmed up at least 10 minutes
Confirm the filter paper in the air sampler is the same filter paper to be utilized for the
sampling activity.
1.
The Digital Flow Meter Series Air Sampler indicates flow rate at a reference T
and P. The F&J Digital Calibrator also displays flow rate at a reference
temperature and pressure. Therefore, a direct comparison can be made between
them if the reference T and P are the same for the calibrator and the air sampler.
2.
Set the calibrator to display the same engineering units that the air sampler is
reading (CFM or LPM). Confirm that the filter paper is installed and that there
isn’t air leakage in the system.
3.
Start the air sampler and adjust to sample at or near maximum flow. Allow the
flow to stabilize prior to documenting the comparison of flows. This
stabilization period may take three to four minutes. Allow both the calibrator
and the air sampler to operate approximately 10 minutes prior to commencing
step No. 4 below.
4.
Compare the flow rate on the calibrator with the reading on the air sampler and
record this information on the calibration data sheet (the following page). It may
be necessary to average the readings over a 15-20 second period if there are
fluctuations in the flow rate value.
5.
Repeat the same process for three other air sampler flow rates whose range is in
the area of interest for sampling. This step is not necessary if you always sample
at a specific flow rate.
6.
Compute the deviations and the % deviations for each of the readings and record
on the calibration data sheet.
7.
Sign and date the data sheet.
8.
Investigate any unacceptable deviations between the calibrator and the air
sampler.
Note that air leakage is the most probable cause for large deviations between the
air sampler and the calibrator
.
