Capacitive capsule for aneroid pressure gauge

An aneroid capsule apparatus for use in a pressure gauge comprising:

• a first membrane having a peripherally extending side edge region;
• a second membrane having a peripherally extending side edge region and a charge retaining region, said first and second membranes extending substantially parallel to and at a distance from each other and being sealingly engaged to each other along their respective peripherally extending side edge regions to define a sealed interior space between them which is partially evacuated;
• means passing through said first membrane and extending between said sealed interior space and the exterior of said capsule apparatus for supporting a capacitor element within said sealed interior space, said support means being electrically conductive;
• means for mounting said supporting means on said first membrane in electrically insulated relationship thereto for movement therewith;
• and
• a capacitor element located within such sealed interior space affixed to and supported by said electrically conductive support means in opposed relationship to said charge retaining region of said second membrane,
• whereby the changes in distance between said first and second membranes resulting from changes in ambient pressure are measured as a function of changes in capacitance of the capacitor plate and opposed charge retaining region of said second membrane.