Signal Group’s highly accurate but simple to operate Gas Divider, the 821S is designed for testing the linearity and calibration of almost any gas analyser. This instrument only requires one calibration gas and a zero gas in order to conduct a full range calibration check.
The linearity of all gas analysers should be checked regularly as part of an effective QA/QC regime. To conduct a reliable, accurate check, users simply connect the calibration gas, the zero gas and the outlet flow connector to the analyser to be tested, and then switch the calibration gas in 10 equal steps from zero to the full concentration. These steps are accurate to within 0.2% and a calibration certificate is supplied with each instrument. Repeatability is 0.5% of the dilution step, and the European and US standards specify 2% accuracy, so if the 10% dilution is selected, 500ppm will be diluted to 50ppm with an uncertainty of 0.25ppm – significantly better than the +/- 1ppm required by international standards.