Thermo Scientific 5030i SHARP, Инструкция по эксплуатации

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Introduction
Principle of Operation
1-6 Model 5030 i SHARP Instruction Manual Thermo Fisher Scientific
A clean filter spot is introduced by an automatic filter change to the
combined sampling and detection chamber at least every 24 hours, usually
centered at midnight. However, the official filter tape change frequency for
TUV and U.S. EPA testing is for both PM
2.5
and PM
10
is every 8 hours.
The automatic filter changes are controlled by the instrument firmware
which halts the pump operation, lowers the vacuum chamber plate,
advances the filter tape a fixed length, raises the vacuum chamber plate, and
initiates the pump operation and a zeroing of the sample spot. Immediately
after a filter change, a new measurement cycle is initiated with an
automatic zero adjustment of the mass signal. The filter change interval and
time of day can be user adjusted. Additionally, automatic filter changes will
occur if the mass on the filter exceeds 1,500 μg since the last filter change
or if the flow rate through the filter tape is reduced by more than 5% due
to potentially restrictive particle deposition.
Using the example of PM
2.5
monitoring, ambient air is drawn into a 10
micron (μm) size selective inlet which discriminates against 50% of the
particles with an equivalent aerodynamic diameter above 10 μm. This inlet
has been approved previously through prior U.S. EPA designations (RFPS-
0699-130, 131, and 132) and is also listed within 40 CFR Part 50,
Appendix L as a 10-MICRON INLET (including model SA246b). Further
particle discrimination is achieved by inserting a PM
2.5
cyclone between the
10-micron inlet and sample tube. European-style inlets are also available
with the 5030
i .The volumetric flow rate at the inlet entrance is 16.67 liters
per minute (1 m 3 /hour). In addition, the ambient temperature and relative
humidity is measured via a naturally aspirated radiation shield and standard
sensor as part of the volumetric flow control and dynamic heating system.
The ambient particulate is then drawn down a vertically mounted heated
sample tube. The heat applied to the sampe is adjustable to either a fixed
temperature or a RH-threshold at the filter spot. The purpose of heating
the sample is to reduce particle bound water and to decrease the relative
humidity (RH) of the sample stream. This is done to reduce positive
artifact measurement that can potentially occur as a result of condensation
on the filter tape or conditions of elevated humidity. The heater is
controlled by the CPU and the power applied is proportional to the
conditions.
Downstream of the heated tube, is the nephelometer assembly. The
particulate travels through the insulated nephelometer in a laminar pathway
and is introduced to the radial tube upstream of the beta attenuation head.
The nephelometer assembly contains an 880 nanometer pulsed light
source, a reference detector for illumination output control, a hybrid silicon
photodetector, temperature sensor, relative humidity sensor, programmable
PCB, and communications cable.
The nephelometer assembly has six ranges that are automatically selected to
provide the most precise reading possible. During scheduled auto-zeroing