Operation Manual HORIBA APDA-371
Particulate Monitor
Date:
April, 2010
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HORIBA Europe GmbH, Julius-Kronenberg-Str. 9, D-42799 Leichlingen,
: +49(0)2175-8978-0,
: +49(0)2175-8978-50
Page 46
•
Some users replace the pump muffler with a 30 inch length of air tubing. This will
not clog and reduces the pump noise as well as the mufflers do.
•
The pump may need to be rebuilt after about 2 years.
•
Medo pumps slowly loose flow capacity as the pump wears out. Eventually, the flow
capacity drops below 16.7 lpm when connected to a APDA.
•
Check the inlet and PM heads for obstructions.
Problem:
The airflow is stuck at a particular rate, and will not change.
Cause/Solution:
•
The flow controller unit on some older units can become stuck. If your flow controller
does not have a small circuit board mounted directly on the motor, it needs to be
upgraded. Contact the Service dept.
•
Set the flow rate in the SETUP > SAMPLE screen to 14.0 and 17.5 lpm, and turn
the pump on in the TEST > PUMP screen. The APDA should try to regulate to these
values. If the flow does not change, the flow controller is probably stuck. If the flow
regulates lower, but not higher than 16.7 lpm, the pump is probably worn out, or
there is a leak. Be sure to set the flow back to 16.7 lpm when done.
Problem:
The nozzle gets stuck in the UP position, or won’t press down onto the tape fully.
Cause/Solution:
•
This is often caused by a misaligned inlet tube. Make sure it is straight up and
perpendicular to the top of the unit.
•
The nozzle o-ring eventually breaks down and needs to be replaced. Contact
HORIBA for detailed instructions. Special shims are required to reinstall the nozzle.
•
The brass nozzle bushings may have grit in them. Remove the nozzle and clean the
parts. Contact HORIBA for detailed instructions. BX-308 tool kit required.
•
Lift the nozzle with your fingers and determine if it feels sticky or gritty.
Problem:
The unit has flow leaks, even after cleaning the nozzle and vane.
Cause/Solution:
•
The nozzle may be sticking as described above. Verify that the nozzle up/down
motion is smooth and complete. If the nozzle feels sticky or gritty, it will not seal
properly. Contact HORIBA for instructions for removing the nozzle and replacing the
internal o-ring.
•
Check the o-rings on the sharp-cut cyclone (if used). These frequently leak.
•
Check the zero of the flow sensor in the APDA: Perform another leak check, but
disconnect the tubing between the pump and the APDA, so there can be no air flow
through the unit. Verify that the flow reading on the APDA reads less than 0.2 lpm. If
not, the flow sensor C
v
and Q
0
settings may need to be recalibrated as described in
Section 5.8 of the APDA manual.
•
Check for bad o-rings on the APDA inlet receiver.
•
Remove the APDA case cover and inspect all air fittings inside the APDA. These
are compression fittings, and must be fully inserted to prevent leaks.
•
Inspect the internal and external flow system for split or cracked air tubing.
Problem:
The unit over-measures or under-measures concentrations compared to a collocated
FRM filter sampler.
Cause/Solution:
•
The most common cause is moisture getting on the filter tape or being absorbed by
the particulate. Review the Smart Heater settings for proper operation.
•
Test the filter RH sensor calibration, and log the filter RH on channel 4 if possible.
RH should be controlled to 35%.
•
Verify the flow rate and temperature and pressure calibrations.
•
Make sure that the K-factor setting has not been changed on the APDA. This would
appear as a slope error in the APDA concentration data.
•
Verify the BKGD (background) value is correct, and perform a 72-hour BX-302 zero
filter test to verify. If the BKGD value is not correct, it will offset the APDA data by up
to several micrograms.
•
Check for leaks at the nozzle. A leak can cause either a positive or a negative
measurement bias depending if the air leaking around the nozzle is cleaner or dirtier
than ambient air.
