BAM 1020-9800 Manual Rev W.docx
Page 65
follower
with a 5/64” hex wrench. The nozzle can now be lifted out of the bushings.
The cam follower, spring, and spacer can be removed from the front of the block.
7. Clean the nozzle inside and out, and inspect the nozzle face for any burrs or defects.
Clean the two brass bushing bores with a cotton-tipped applicator. This is also a good
time to clean and inspect the tape support vane since the nozzle is out of the way. The
bushings do not need to be lubricated. Reinstall the cam follower, spring, and spacer,
and align them with the bushing bores.
8. Lower the nozzle down through the bore. The two brass shims must be positioned as
shown before the set screws are tightened to retain the nozzle. The square shim must
be under the nozzle face. The slotted shim goes under the cam follower. Tighten the
set screws evenly, only a little at a time to avoid distorting or binding the nozzle.
9. Remove the shims and check the up/down action of the nozzle before reassembling
the nozzle adapter and inlet receiver. It must feel smooth and even after each step of
reassembly. If the nozzle still binds or sticks, then contact technical service.
Nozzle Removal
Cleaning the Bushings
Using Shims for Reassembly
7.7 Performing the 72-Hour Zero Filter Background Test
All BAM 1020 monitors should have a zero-filter test performed before the equipment is first
deployed so that an initial BKGD adjustment may be made if necessary. We recommend
repeating this test periodically as part of a QA/QC program, the frequency of which is up to
the user.
When the BAM 1020 is set up for the first time we recommend that a minimum of 48-72 valid
1-hour data points be collected in order to accurately determine the BKGD value. The initial
zero-test allows the
user to determine the instrument noise (σ) and to confirm that the lower
limit of detection (LLD), which is 2σ, is within specifications. For an 8-minute count cycle the
LLD is specified to be <4.8 μg/m
3
for a 1-hour measurement cycle and for a 4 minute count
cycle the LLD is specified to be <7 μg/m
3
. We recommend that the initial zero test and
subsequent zero tests be performed using an 8-minute count cycle if the BAM 1020 will be
operated with an 8-minute count cycle and that the initial zero test and subsequent zero tests
be performed with a 4-minute count cycle if the BAM 1020 will be operated with a 4-minute
count cycle.
If the BAM 1020 is to be operated with a “smart heater” (BX-826 or BX-827) we recommend
that the initial zero-filter test be performed on a laboratory bench or at the monitoring site with
the smart-
heater engaged, but running in “simmer mode” only for the duration of the test.
Simmer mode is maintained by ensuring that the RH set point on the smart heater always
exceeds the RH of the sampled air after the sampled air is warmed or cooled to the filter
2 or 3 Set
Screws
Shims
8236, 8235
