PRESSURE-MEASURING CELL, PRESSURE-MEASURING DEVICE AND METHOD FOR MONITORING PRESSURE WITHIN A CHAMBER

摘要

The present invention relates to a simple and compact pressure-measuring cell (3) which is arranged in a protection tube (1) and which can be produced at low cost. In order to cover a wide measuring range from about 10-6 mbar to about 10 bars, the cell comprises a ceramic membrane (6) on a support plate (5), wherein said membrane forms together with the plate (5) a capacitive measuring element for determining pressures between about 0.1 mbar and 10 bars. The cell also includes two measuring wires (11, 12) which are arranged by the membrane (6) and which form a thermal-conductivity measuring element with a substantial compensation for the influence of the wall temperature, wherein said element is used for measuring pressures from about 10-6 mbar to 10 mbars. A protection ring (16) is used for protecting the membrane (6) against the radiation from the measuring wires (11, 12). In order to improve stability in the long run, the offset of the capacitive measuring element under pressures of less than 50 mbars can be compensated by comparison with the thermal-conductivity measuring element.