Sintrol S303 - Principle of Operation and Limitations; 5.1-5.2 Particle Material and Size Influence

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5 Principle of operation, physical effects, and limitations
Sintrol dust monitors are based on a unique Inductive
Electrification technology. The measurement is based on
particles interacting with an isolated probe mounted into the
duct or stack. When moving particles pass nearby or hit the
probe a signal is induced. This signal is then processed through a
series of Sintrol’s advanced algorithms to filter out the noise and
provide the most accurate dust measurement output.
Classic triboelectric technology is based on the DC signal, which is
caused by particles making contact with the sensor to transfer
charges. Compared to DC based measurements, the Inductive
Electrification technology is more sensitive and minimizes the
influence of sensor contamination, temperature drift and velocity
changes. By using the Inductive Electrification
Technology it is possible to reach a detection limit as low
as 0.01 mg/m3.
According to its position in the Triboelectric Table each material transfers a specific charge to the probe.
Inorganic, electro-conductive materials (metals) create the lowest signals, Inorganic dielectric materials
(cement, minerals) generate average signals, Organic dielectric materials (wood, flour) generate the highest
Signals. This charge is captured by our sensor and its signal level is proportional to the particle concentration.
As a unit for this signal level the Inductive Electrification Unit (IEU) is used.
The relation between Inductive Electrification Unit (IEU) and the mA output signal can be established by
performing the Auto Setup function.
The relation between Inductive Electrification Unit (IEU) and the dust concentration in mg/m
3
can be done by
calibrating the signal to a reference method e.g. to the results of a gravimetric sampling series.
5.1 Influence of particle material
The signals transmitted by different types of dust particles vary greatly from one material to the other. For
example:
 Inorganic electro-conductive materials (metals) create the lowest signals.
 Inorganic dielectric materials (cement, minerals) generate average signals.
 Organic dielectric materials (wood, flour) generate the highest signals.
This means that at the same concentration, different types of dusts generate different output signals. This
behavior can be compared to the behavior of opacity monitors, which show a different result depending on
the color of the material: at the same concentration, black dust will show less opacity than white dust.
5.2 Particle size
In terms of particle size, 425µm (40 mesh) is generally defined as the limiting size to classify a material as a
“dust.”
 The minimum particle size which the S303 or S304 is able to detect is 0.3 µm.
 The best working range of the S303 or S304 is between 1 and 200 µm.
Figure 1: Inductive Electrification Technology