TSI Incorporated 8587A, Руководство по эксплуатации и обслуживанию

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3-16 Model 8587A Laser Photometer
Pressure Transducer
A pressure transducer measures the differential pressure across the orifice
and valve (see Figures 3-3 and 3-5) to ensure the required vacuum creates
the correct sample airflow. At the factory, the sample airflow is set with a
differential vacuum of 55 kPa (8 psi) or greater, generating a
“critical
airflow
” of 2 L/min (0.071 cfm).
As shown in the data table below, vacuum greater than 55 kPa (8 psi) will
result in a constant 2 L/min (0.07 cfm)
sample or “critical airflow”.
Although the ideal vacuum is >55 kPa (8.0 psi), the instrument will operate
correctly at vacuums as low as 30 kPa (4.4 psi). However, when the
vacuum across the orifice falls below 30 kPa (4.4 psi), the pressure
transducer indicates a flow error, causing the flow status light to blink.
Electronics Boards
Four electronics boards are used in the Model 8587A. The boards include
Main PC board, laser board, detector board, communication connector
board. The main board has the microprocessor and performs all intelligent
functionality, controlling valves and reading inputs and performing basic
calculations. The laser and detector boards power the laser and detect
scattered laser light from particles in the aerosol stream. The detector
board has relays for gain control. The communications board supports the
USB and RS-232 serial connectors.
kPa psi L/min cfm
18 2.6 1.50 0.053
22 3.2 1.60 0.057
26 3.8 1.70 0.060
30 4.4 1.79 0.063
42 6.1 1.90 0.067
45 6.5 1.95 0.069
55 8.0 2.00 0.071
60 8.7 2.00 0.071
71 10.3 2.00 0.071
81 11.7 2.00 0.071
Pressure Volumetric Flow
Vacuum and airflow is too low.
FLOW STATUS indicator light
blinks.
Acceptable vacuum and airflow
range. FLOW STATUS
indicator light is on.