Met One E-BAM, Руководство по эксплуатации

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E-BAM-9805 Manual Rev B.docx Page 36
5.2 Basic Leak Check
The E-BAM PLUS flow system must be checked for leaks periodically (see Table 5-1), after every
filter tape change, and before any flow calibrations are performed. Enter the Leak Test screen (see
section 3.5.1). The tape will automatically advance to a clean spot and the vane will rise when this
screen is entered.
Figure 5-1 Leak Test
Under test conditions, vacuum in the flow system is several times greater than during normal
sampling. This state exaggerates any leaks. If a leak found during this test is less than or equal to
1.5 lpm, there should not be a significant leak during normal operation. A leak of greater than 1.5
Lpm must be corrected immediately.
As-found leak checks (before cleaning the nozzle and vane) may be performed for data validation
purposes. The recommended threshold for invalidating as-found leak values (before cleaning
nozzle and vane) is 1.5 lpm or higher.
Routine cleaning of the Nozzle/Vane interface is recommended to prevent leaks from developing.
See section 5.5.1 for cleaning instructions.
Important Notes About Leak Checks:
Leaks may be caused by degraded O-rings or an improper inlet tube to receiver connection, but
almost all air leaks in the E-BAM occur where the nozzle contacts the filter tape. Because the
airflow sensor is located downstream of the filter tape the E-BAM has no way of automatically
detecting a leak at this interface.
There will normally be a small amount of leakage at the tape, but an excessive leak lets an
unknown amount of air enter the system through the leak instead of the inlet. This will cause the air
volume calculation and the concentration measurement to be incorrect.
Allowing a leak to persist
may cause data to be invalidated back to the last known good leak check.
Required Tools : Leak Check Valve (Part No. BX-305 or included as part of the BX-302)
Use the following steps to conduct the basic leak check:
1. Remove the PM
10
head from the inlet tube. Install a BX-305 leak test valve, BX-302 zero
filter, or equivalent valve for leak checking FRM samplers onto the inlet tube (see Figure
5-2). If a PM2.5 inlet cyclone is used, it is usually best to install the leak valve above the
cyclone in order to test it for leaks as well. The BX-305 valve should be open.
2. Navigate to the TEST>TAPE TEST menu. Move tape and exit.
3. Navigate to the TEST>LEAK TEST screen.
4. Verify the nozzle is in the down position. If it is not, press the NOZZLE control button to lower