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Introduction
General
The ADR-1500 is a complete particulate monitoring system designed to
provide the user with continuous measurements of the concentration of
Description
airborne particles for suspended particulate and 50% cut-points ranging
from PM
down to PM
, that is, the concentration of particles smaller
10
1
than 10 μm down to 1 μm aerodynamic equivalent diameter, respectively.
Reference should be made to
Figure 5–1
of this manual for the location
and identification of various component elements of the ADR-1500,
described in this and subsequent sections of this manual.
The ADR-1500 samples the air through an omni-directional inlet, which
ensures representative sampling of suspended particles, even under windy
conditions. This inlet rises about 30 cm over the upper surface of the ADR-
1500 enclosure. The sampled air stream can then enter an optional cyclone
located downstream of the inlet, wherein particles larger than the cut-off
diameter of the cyclone are retained, and those smaller than the cut-off
diameter continue into the optical sensing stage of the monitor. The
particle cut-off size is dependent on the sampling flow rate.
After the inlet assembly, the stream enters the optical sensing stage where
the instantaneous concentration of airborne particulate matter is measured
by light scattering photometry. It is important to point out that this
sensing technique is independent of the speed with which the particles pass
through the sensing stage, and therefore changes in flow rate have no effect
on the measured concentration. However, changes in the flow rate will
affect the particle cut-point if an optional cyclone is used.
After the particle mass concentration has been sensed photometrical, the
stream passes through either a HEPA filter capsule (for long-term
monitoring) or a standard 37-mm filter holder within which a membrane
or fiber filter can be installed for further particle analysis (gravimetric,
microscopic, chemical, etc.). When using the ADR-1500 for continuous
unattended monitoring, however, it is advisable to use the HEPA capsule.
After passing through the filter stage, the filtered air stream then enters the
flow assembly. This assembly contains a rotary vane pump and a
volumetric flow rate control system based on sensing the pressure drop
across a sub-sonic orifice that is protected by an inline filter. The sampling
flow rate can be selected by keypad control on the front panel of the
instrument.
After passing through the flow assembly, the air is exhausted from the
ADR-1500 enclosure through a small bulkhead fitting. This exhaust port
can also be used as a flow return in special sampling applications where the
inlet of the ADR-1500 is connected to an environment at either positive or
negative pressure (with respect to ambient).
Thermo Fisher Scientific
MIE ADR-1500 Instruction Manual
1-3
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Troubleshooting
