Eurotron BTU 1000, Instruction Manual

Page: 9 / 47

Manual instruction MM850482 ed.04
9
3 PRINCIPLE OF OPERATION
UniGas 1000
analyzer is based on the following functional blocks:
MicroController
Built-in Impact
Printer
Keyboard
Display
Power supply
Ni-MH
batteries
Charger connector
Pt100 Tair probe input
Gas Outlet
IR printer port
P2 - ∆ 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
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 center 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 UniGas every time the instrument 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 analyzer 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 an automatic back light device for easy readings, also in poor light conditions.
3.1.1 Gas Sampling Probe
The sampling probe consists of a steel tube and a handle of thermo insulating material. A positioning cone
allows placing 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 top of the tip.