Description:
A
portable and passive gas dilutor that is “charged” with a Standard gas mixture
and when connected onto a cylinder of diluting gas provides a flow of “zero” gas
and seven selectable dilutions of the Standard mixture.
Main
Features
The
AGS is portable, rugged, weather proof and requires no power, so is
intrinsically safe. Little Standard gas is consumed due to the high dilution
ratios of ~1:1000.
Applications
The AGS is ideal for
in-fi eld calibration and linearity testing of gas analyzers and some laboratory
applications, especially to provide low concentration mixtures that would not be
stable if stored in cylinders
Development
Status
Small
quantities have been built using dedicated investment castings and standard
components. Tests demonstrate the dilution ratio accuracy of ±1%, relative, is
maintained from 0°C to 40°C and stable over 6 months.
Availability
Technology is
available for licence
IP
Status
UK
Patent Application GB2446409A, published 13.08.2008
PCT
Application WO 2008/096101 A2, published 14.08.2008
USA
and Japan patent applications are in progress.
Technical
Critical orifices and
a pressure regulator determine the flows of the Standard and Diluent gases.
Operation uses the principle that gas dilution ratio is defined by gas flow
ratio, with no need to accurately control absolute flow rates. Both gases are
supplied to the orifices at equal pressures and temperatures to ensure that the
flow ratios are constant. Three taps are switched in combination to select seven
different flows of the Standard mixture that are added to a fixed flow of
diluent gas. These flows can be configured to give seven equal increments of
concentration with dilutions of 1:2000 through 7:2000, or tailored to meet
specific requirements.
