Met One E-BAM, Руководство по эксплуатации

Страница: 42 / 64

E-BAM-9805 Manual Rev B.docx Page 42
13. Go to the Operate menu and select Stop Sample to stop the current sample, if the monitor is
still sampling.
14. Remove the zero filter from the inlet tube and install the size selective inlet(s)
15. Resume normal sampling.
NOTES:
For best results, the zero-filter background test should be performed during a period of fairly stable
weather.
The zero-filter cartridge should be replaced if there are any obvious signs of discoloration due to
aging or the aspiration of water. See section 7.1 for ordering details.
To determine the hourly zero noise and hourly lower detection limit, calculate the standard deviation
of the most recent 48 hourly PM concentrations (the values used in step 9 above). The standard
deviation (σ) should be less than 5 µg. The hourly detection limit is defined as two times the
standard deviation (2σ).
If the standard deviation is greater than 5 µg, the cause should be investigated. Contact the Met
One Instruments service department (see section 1.2) for assistance.
5.5 Nozzle/Vane Cleaning
The inside of the E-BAM sample nozzle should be periodically cleaned to remove any particulate
which may have settled on the inside surfaces. This cleaning prevents any buildup of particulate
which could result in artifacts falling out of the nozzle and onto the tape, causing undesired positive
concentration spikes.
The nozzle and vane (located under the tape) must be cleaned regularly to prevent leaks and
measurement errors. The cleaning must be done at least each time the filter tape is changed,
though monthly cleaning is highly recommended. Some sites will require more frequent cleaning as
determined by the site administrator. The worst environment for nozzle contamination is hot, humid
environments. This is because damp filter tape fibers more easily stick to the nozzle and vane. The
fibers can quickly build up, creating air leaks or punching small holes in the filter tape which will
cause measurement errors.
5.5.1 Nozzle/Vane Cleaning
Use the following steps to clean the nozzle/vane interface:
1. It is advisable to perform an as-found leak check (section 5.2) before cleaning the nozzle, in
order to validate past data as being leak-free.
2. If the nozzle is down, raise it by pressing the NOZZLE button in the Leak Test screen.
3. Remove the filter tape (if installed) from the nozzle area to allow access to the vane.