| Автор | Weinheimer, Andrew J. |
| Автор | Ridley, Brian A. |
| Дата выпуска | 1990 |
| dc.description | Commercial mass flow controllers are widely used in atmospheric research where precise and constant gas flows are required. We have determined, however, that some commonly used controllers are far more sensitive to ambient pressure than is acknowledged in the literature of the manufacturers. Since a flow error can lead directly to a measurement error of the same magnitude, this is a matter of great concern. Indeed, in our particular application, were we not aware of this problem, our measurements would be subject to a systematic error that increased with altitude (i.e., a drift), up to a factor of 2 at the highest altitudes (∼37 km). In this note we present laboratory measurements of the errors of two brands of flow controllers when operated at pressures down to a few millibars. The errors are as large as a factor of 2 to 3 and depend not simply on the ambient pressure at a given time, but also on the pressure history. In addition there is a large dependence on flow setting. In light of these flow errors, some past measurements of chemical species in the stratosphere will need to be revised. |
| Формат | application.pdf |
| Копирайт | Copyright 1990 by the American Geophysical Union. |
| Тема | ATMOSPHERIC COMPOSITION AND STRUCTURE |
| Тема | Middle atmosphere: composition and chemistry |
| Тема | Instruments and techniques |
| Название | A cautionary note on the use of some mass flow controllers |
| Тип | article |
| DOI | 10.1029/JD095iD07p09817 |
| Electronic ISSN | 2156-2202 |
| Print ISSN | 0148-0227 |
| Журнал | Journal of Geophysical Research: Atmospheres |
| Том | 95 |
| Первая страница | 9817 |
| Последняя страница | 9821 |
| Выпуск | D7 |
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