An automated gas mass flow calibration transfer standard
An automated gas mass flow calibration transfer standard
Keyword: Flow
The new CAL2009 was developed to provide the lowest uncertainties for flow in a commercial calibration laboratory. It has all the advantages of labour-saving automatic control and data handling and ISO/IEC 17025 compliant calibration sheets are printed immediately after the last calibration point (Plate 1).
Up to 100std.litre/min, flows are verified on-line using molbloc™precision laminar flow elements in series with 300 Series Hastings thermal mass flow controllers (MFC). The molbloc has become the standard of choice throughout the world for mass flow – it provides extremely high repeatability of its fundamental, gravimetric calibration. Data from the molblocs is handled by DH Instruments' molbox™, in which all the fundamental gas physical constants are held in memory and applied as the measurement is made.
Plate 1
Above 100slpm (and up to 2000slpm), flows are controlled and measured by Hastings Instruments' 300 Series MFCs, which have been developed for the highest repeatability and combined linearity of better than 1 per cent. The CAL2009 addresses the MFCs when required and, when handling their output, applies a sixth order polynomial to further reduce overall uncertainty.
Software for the CAL2009 has been written by engineers for convenient use by calibration engineers and all procedures are pre-programmed to comply with ISO/IEC17025, as required in our UKAS calibration laboratory.
Chell Instruments has over 25 years experience of mass flow measurement and control, all at the forefront of performance; they are thus well placed to design and construct calibration solutions for both calibration laboratories and end-users alike. Compliance with the acknowledged International Standards and provision of the lowest uncertainties commercially available, is easy using the CAL2009.
Chell maintain UKAS Calibration Laboratory No. 0687 in support of all measurement and controlling instruments it supplies, and provides service for life.
For further information contact: Ron Mitchell, Chell Instruments Ltd, Folgate House, Folgate Road, North Walsham NR28 0AJ, UK. Tel: +44 (0)1692 500555;E-mail: arm@chell.co.uk
