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PRODUCT
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CAPILLARIES
BASED GAS BLENDER FOR
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GAS
ANALYSERS TEST - BETACAP30
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DESCRIPTION
Sometime
it's required the availability of many gas concentrations for the
calibration of an analyser in various points of the range or in various
ranges. Zero and sensitivity calibrations are not enough for assuring the
instrument accuracy because the non linearity response is disregarded. The
response check of an instrument in some point of the range is not only
suggested by “good practice”, but requested by environmental laws and by
norms for approval of components which involves combustion (engines, burners, boilers, …).
BetaCAP30 is made by 30 identical
capillaries, which are individually connected to the gas to be diluted or
to the diluting gas. It's then generated a mixture which may have one of 31
different concentration values, depending on the ratio of the capillaries
number connected to one source and the capillaries number connected to the
other source.
Each capillary will be crossed by
the gas to be diluted or by the diluting gas : the diluted flow will be 30
times the single capillary flow.
To assure the matching of all the
capillary flows, the pressure of the 2 gas inlets must be adjusted at the
same value or at suitable values to compensate the differences in density
and viscosity of the different gases. For that reason, differential pressure
across capillaries is continuously measured and displayed to support the
user.
A suitable adjustment of inlet
pressures, allows the production of different gas flows : selecting
pressures in the range 50...200 kPa, the output flow may change in the range
1...4 litres/min. Upon request, different capillary sizes may be selected
to cover different ranges.
Two fine filters protects from dust
the pressure regulators and capillaries : keeping clean that area is the
best assurance for high accuracy and long life of the gas blender.
In addition, the mechanical
assembling is rugged and shocks absorbing, to avoid misalignments or cracks
and compact in size to be easily transported.
The main part of the instrument is
a manifold which holds in place and create the circuit for the capillaries
: they are got by cutting one long capillary tube . On the same manifold,
solenoid valves with separation diaphragm are faced to address the right
gas inlet to the right capillaries group. Individuals capillaries are
selected by fluid-dynamic test and matched before installation, to get the
best accuracy of the unit .
All of the internal parts may be
inspected for cleaning or replacement, and the used materials are highly
resistant to aggressive gases : Aisi 316, borosilicate glass, PVDF, PEEK,
Kalrez, epoxy resin.
A microprocessor electronic circuit
manages all the functions interfacing with the user through an alphanumeric
display and five function keys.
Two main menus are used to
calibrate the input pressure measurements and the input current signal from
the instrument under test. One menu is used to define parameters like test
gas bottle concentration and analyser measuring range. Two menus are ready
for operating the dilutor locally or remotely from a PC via RS232.
The user inputs test gas bottles
and analyser data, and then selects the number of dilution steps :
theoretical and measured concentration is automatically displayed.
Through the serial interface, a PC
with the suitable software (Terminal or a dedicated program) may send to
the gas divider the dilution ratio and receive the instrument measuring
signal : recording
those values for each step, the
test report may be automatically drawn.
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TECHNICAL SPECIFICATIONS
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Dilution ratio:
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adjustable from 0 to 100% in 32 steps
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Pneumatic taps inlets :
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diluting gas and gas to be diluted
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outlet :
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diluted gas
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Accuracy:
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better than 0.2 % of the concentration to be diluted
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Repeatability :
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better than 0.1 % of the
concentration to be diluted.
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Gas contact. materials :
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AISI 316, borosilicate glass,
PVDF, PEEK, Kalrez, epoxy resin.
Analog measurements 2
differential pressures and gas analyser measurement
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Size and weight :
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portable version 270 x 250 h 180 mm - weight 10 kg - IP67
laboratory version rack 19” std. 3UT - dept 250 mm
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Serial interface :
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RS232 to download test data to a PC
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Power supply :
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110 / 220 Vac - 2 A - (different values ac / dc at request)
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Internal
view, with filters pressure sensors..
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