KIN-TEK’s Span Pac™ I – SD (secondary dilution) uses readily available Trace Source™ Permeation Tubes to add a precisely known flow of span vapor into a controlled, adjustable flow of clean matrix gas to create a PPM calibration standard.
A second dilution stage then takes an adjustable aliquot of that primary mixture and further dilutes it with matrix gas to create substantially lower concentrations. This two-stage dilution method allows the output concentration to be varied seamlessly over a range of up to 10,000:1 from a single permeation tube. Higher rate Trace Source™ permeation tubes are more precise and readily available than extremely low rate tubes.
An alternate function of the two-stage dilution system is to create adjustable concentration while maintaining constant total flow. In this mode, the concentration can still be varied over a range of up to 400:1.
The Standard Additions Technique is used to compensate for residual contamination in the matrix gas. In use, accuracy of the measuring device is achieved by calibration on the differential response due to calibration gas addition.