IQM 60 V5 Pump Revision October 2010
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5.2 Particle Counter Calibration
Flow rate
The sampling flow rate should be checked monthly and adjusted if required. To test the flow rate:
1. Remove the isokinetic probe and connect a flow meter to the barb fitting of the particle inlet using a short
piece of flexible 1/8 “ ID tubing, Tygon tubing is a good choice.
2. Turn on the IQM and note the flow meter reading. The flow rate should be 1.0 +/- 0.05 LPM
3. The flow rate can be adjusted by a screw flow adjuster located underneath the bottom panel of the IQM
(see below). To remove the bottom panel, remove the two screws located at the bottom rear corners of the
casing and the bottom panel lifts off. Use a screw diver to adjust the screw in the T piece fitting. Turn the
screw clockwise to decrease the flow and counter-clockwise to increase the flow.
Zero Check
It is recommended to periodically perform a zero count test as described below. False counts caused by air
leaks or spurious noise will cause errors that are especially apparent when sampling relatively clean
aerosols.
1. Attach a filter with a rating of 0.45µm or better to the particle inlet nozzle. The filter must be large enough
that it does not create a restriction and load down the small vacuum pump inside the IQM. One zero
particulate filter is supplied with the IQM.
2. Since the air passing through the IQM is now virtually particle free the output particle count should be
zero. If it is not, check for leaks around the tubing to the particle counter.
Span Calibration
There are no user serviceable components inside the particle counter instrument. The cover on the particle
counter should not be removed or opened for servicing, calibration or any other purpose except by a factory
authorized person. To do so will void warranty and may result in exposure to invisible laser radiation that
can cause blindness. Contact Aeroqual for service information. Calibrating particle sensors like the one in
the IQM requires specialized equipment and a skilled technician. The particle counter should be factory
calibrated on a yearly basis.
Particle Counter flow
adjustment screw
