Instruction Manual MM850404 ed.05
14
3
PRINCIPLE OF OPERATION
The 2000 series
analyzer is based on the following functional blocks:
MicroController
Built-in Impact
Printer
Keyboard
Display
analysis
data
memory
Power supply
Ni-MH
batteries
Charger connector
External probe input
Pt100 Tair probe input
Gas Outlet
IR printer port
P2 -
Δ
P
P1 – Draft/Pressure
Differential
pressure
sensor
Gas INLET
Pump
1th Sensor O2
2nd Sensor CO
Methan sensor
TcK Tgas input
Water trap
Line Filter
Serial interface
3.1 Measurement
Principle
The gas is sampled and aspirated through the probe with a primary pump powered at constant voltage.
To position the sampling probe in the exhaust gas pathway a hole of 11mm, up to 16mm, should be drilled and the
retaining cone of the sampling probe firmly screwed in it.
The retaining screw in the cone enables the probe to be easily moved to locate the core flow, normally
correspondent to the centre of the section of the chimney
. The flue gas and exhaust gas pathway, should be
checked for gas-tightness before carrying out a measurement and, if necessary, non gas-tight points should be sealed.
The O
2
sensor is essentially an electrochemical cell, with two electrodes and electrolyte solution. The behaviour is similar
to a normal battery and therefore the sensitivity decreases with time.
The electrochemical cell grants accurate results for time intervals of approximately 60 minutes. The zero drift is
automatically corrected by the instrument every time is switched-on, using fresh ambient air as reference. This operation
should be made with the sampling probe not inserted in the chimney or with the sampling probe pneumatic connector
disconnected from the analyser gas inlet.
When a long time analysis has to be made, a new autozero procedure should be performed.
Measured and calculated parameters are indicated on a LCD alphanumeric display (40x56 mm), equipped with a
automatic back light device for easy readings, especially in poorly lit conditions.
3.1.1
Gas Sampling Probe
The sampling probe consists of a steel tube and a handle of thermoinsulating material. A positioning cone allows the
user to place the probe in holes with a diameter from 11 to 16 mm.
The gas temperature is acquired using a thermocouple type K with the junction placed on the tip of the probe.
3.1.2
Water Trap & Line Filter
The gas flows through an external combined water trap and line filter to avoid the presence of condensation and
suspended solid particles in the analysis section of the instrument. A cylinder is positioned at 15 cm from the instrument
gas inlet it is divided into two parts: the water trap and the line filter.
