New methods to calibrate low gas flow

The aim of the project is to calibrate low mass gas flows and standard / fixed leaks with good accuracy.

For Swedish industry, low mass flows are measured in many different ways. To ensure the output and quality of industrial processes dependent on gas flow, it is necessary to get so-called "reference leaks" calibrated. In the Nordic countries it is today not possible to obtain an accredited calibration for these at all, and services abroad give large uncertainties.

New contact-less method

Current methods to calibrate small flows and gas leaks have relatively large measurement uncertainties. The aim of the project is to create a method and build up a service in Sweden which offers the possibility to get internationally recognized and improved measurement techniques. The idea is to combine optical refractometer measurements and vacuum technology in order to get a more accurate and also contact-less method.

Accurate density measurement

A feasibility study has been performed, exploring the possibilities to implement contact-less determination of gas density using laser refractometry. The study shows that with this method, changes of gas density in the gas flow gauge at the leak calibration can be determined with a better accuracy than today.

Better measurement uncertainty

A measurement method in which the gas flow is not affected by the test would mean a major development in the area. Methods used by other laboratories currently have largest uncertainty contributions just from the measurement of the flow.

Cooperation with Universities and academies

Ultimately, the equipment developed in this project could also be used for calibration of ultra-high vacuum (UHV) gauges. The project is implemented within the framework of a doctoral collaboration with Uppsala University which led during the first half of 2006 to a licentiate. During spring 2009 a Master’s student from Umeå University, Sweden, is active in the project.

Courses and seminars

In this project, we have held several courses and seminars on density control and leak detection. These have mainly been focused on the industrial need for leak detection.

Calibration of vacuum gauges

Vacuum gauges that indicate that a process is operating at the ”correct” pressure level are important in many industrial processes. Read more...
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