Автор: Alex-Hotmail
Дата: 03.10.07 13:46
Oleg,
I believe You may evaluate the following options:
1- turbine flowmeter. Low-cost solution; do not take in account a variation
of gas density due to the temperature variation. Negative aspects: in case
of pulsating flow (wide variations in the limited period of time) the
inertia of turbine wheel introduces additional error.
2- variable area flowmeter. Med-cost solution (price of the 4-20mA
transducer is high). In addition, You have to modify the pipe because
rotameters normally operate on the vertically rising flow; there exist
spring-loaded models operating in horizontal, but its precision is poor.
Please consult a manufacturer, because fluid velocity is too low, so it is
to be used very light floater; I do not know if very light floaters may be
equipped with magnet, necessary for the position transmission to the
transducer
3- thermal dispersion flowmeter (produced, for instance, by FCI). Cost is
high, and the responce time in case of variation of the flow is significant,
but the instrument is extremely reliable. In case of use of this type of
instrument please consult the manufacturer for the correct definition of
calibration parameters; these parameters depend on the thermal conductivity
of exhaust gas. Anyway, it is the only solution permitting You to get a mass
flow of gas; solutions 1/2 provide You volumetric flow.
For Pitot tube and vortex flowmeter, I think, pipe diameter is too small,
and flow velocities are low.
Best regards
Alex
Oleksii FILIPOV
Jordan Technologies Europe
[Non-text portions of this message have been removed]
|
|
