ANNEXES
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Manual EC 24 · EN05 · 2015-02
41
Functional description
The measuring element directly measures the flow rate at measurement conditions and in the top-
mounted meter head or corrector the measured values are integrated so that the result is the gas
volume which flowed through the meter. The gas flow drives a turbine wheel whose speed is
recorded through non-contact measurement by a sensor. Therefore, the meter is characterized by
long-term stability and low wear.
An aerodynamic flow straightener (8) fitted into the meter case constricts the effective cross
section of the pipe to form a ring-shaped cross-sectional area and substantially eliminates
turbulence. The velocity of the flowing gas increases and the gas is directed to the turbine blades.
The turbine wheel (7) is dynamically balanced and mounted with dust-proof ball bearings (6). A
permanent magnet (4) located at the end plate of the turbine shaft induces the sensor element (3)
to give a voltage pulse with each rotation of the turbine wheel. This pulse is further processed by
the electronic system of the meter head (1).
Inside the meter head or corrector, the number of pulses is divided by the meter factor (number of
pulses per m
3
) and the result is used to calculate the volume at measurement conditions. In the main
totalizer, the sum of the volume at measurement conditions which flowed through the meter is formed
and you can read the gas volume which flowed through the meter per time unit on the flow rate display.
At the HF output (only in the case of an electronic measuring element), the unchanged signal
frequency of the sensor element is outputted, whereas, for the LF output, this HF frequency can be
reduced by two programmable scaling factors.
Operating conditions
Permissible types of gases
The
standard design
of the TRZ 03 – TE / TEL turbine meters can be used for all non-aggressive
gases, such as
Natural gas
Air
Town gas
Acetylene
Methane Helium
Ethane
Carbon dioxide (dry)
Propane Nitrogen
Butane Hydrogen
Special designs
(PTFE lining, special lubrication, special material, etc.) can be used for aggressive
and humid gases, such as
Ethylene Digester
gas
Biogas Sulphur
dioxide
Acid gas
etc.
