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Chell’s ISO17025 accredited UKAS Laboratory

Vacuum

 


The colloquial term 'vacuum' is still technically a pressure measurement and is amongst the most difficult pressure measurements to undertake.

Chell is accredited to perform vacuum calibrations down to 1.3x10-4 Pa
(1x10-6 Torr), employing a range of different fundamental and Transfer Standards. All calibrations are performed using pure oxygen free nitrogen as the test gas.
Three high accuracy capacitance manometer transfer standards are used from 1333Pa down to 1x10-1 Pa. These devices have up to 4 decades of range overlap, providing a high degree of cross-comparative confidence. Traceability is direct from the National Vacuum Standard held by NPL in Teddington and the highest level of confidence is provided by over fourteen years of NPL calibration history on these standards. Calibration and drift errors are corrected using audited bespoke linear regression software. These standards are regularly cross-compared at 1x10-1 Pa with a Spinning Roter Gauge and at 1333Pa with a 60inch Schwien manometer producing a vacuum calibration facility with outstandingly low uncertainties.

A gas friction manometer (Spinning Rotor Gauge) is used for high vacuum calibrations over the range 1x10-4 Pa to 1x10-1 Pa. Traceability is bought-in from a German DKD accredited vacuum laboratory providing traceability to the German National Standards at PTB, Berlin.

Chell has nearly thirty years' experience in the calibration and repair of vacuum instrumentation & controllers from all the major manufacturers and this knowledge ensures that these often most delicate of devices are handled appropriately.

The generic type of instruments supported include:

  • Capacitance manometers
  • Pirani & thermocouple gauges
  • Cold Cathode & inverted magnetron Ion gauges
  • Vacuum transducers & transmitters
  • Vacuum switches
  • Spinning rotor gauges

Extract from our UKAS Schedule of Accreditation, Issue 013

DETAIL OF ACCREDITATION
Measured Quantity
Instrument or Gauge
 Range Best Measurement
Capability Expressed as
an Expanded Uncertainty
(k=2)
 Remarks

Vacuum

Calibration of indicating instruments
and gauges

 

1.3 x 10-4 Pa to 7 x 10-2 Pa
7 x 10-2 Pa to 1.33 Pa
1.33 Pa to 13.3 Pa
13.3 Pa to 1.33 kPa
1.33 kPa to 13.3 kPa
13.3 kPa to 133 kPa

 6% + 4 x 10-5 Pa
1% + 2 x 10-3 Pa
0.6% + 2 x 10-2 Pa
0.5% + 8 x 10-2 Pa
0.2% + 3 Pa
0.2 % + 9 Pa

Calibration of instruments with an electrical or frequency output may
be undertaken

Calibration of thermionic and gas friction gauges can be undertaken

 

If you have any questions or would like to know more details about our calibration laboratory and the service it provides, please do not hesitate to contact us.

Email address
Telephone 01692 500555
Fax number 01692 500088



Chell Instruments