To obtain a heat-loss pressure gage which enhances the accuracy of the measurement of a pressure in a range from a low pressure up to a high pressure.
A Pirani gage is provided with a small-diameter-wire detecting element 12, a small-diameter-wire correction element 14 which is situated on the same face as it and two heat-conductive plates 16 which are separated from the elements and which are parallel and flat. The physical size, the thermal characteristic and the resistance characteristic of the detecting element 12, the correction element 14 and their coupling element are identical. The coupling element comprises a large heat-conductive property to a uniform temperature region, and both elements are placed in an identical vacuum environment. A DC heating current is used only for the detecting element 12. A comparatively small AC signal is used to detect the balance of a bridge. Then, by a simple three-dimensional pressure correction system, a correction is performed precisely, and the acquisition of calibration data is simplified.
Borenstein, Michael Dale
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