Patent ID: 7114384

Claim:
A system for measuring the volume V 1 of a gas in a main closed chamber, comprising: a reference chamber having a known volume V 2 and mounted in a back-to-back configuration with a common surface of said main chamber, the surface between and dividing the main and reference chambers; means disposed in said surface for equalizing the static gas pressure in the respective main and reference chambers, wherein said equalizing means comprises one or more open passages disposed in said surface communicating between said reference chamber and said main chamber; an excitation transducer for producing a volume displacement of the same magnitude in the respective chambers; an excitation source for generating an excitation signal for driving the excitation transducer; a main chamber pressure sensing means for providing a main transducer signal indicative of the differential gas pressure P 1 in the main chamber caused by the volume displacement; a reference chamber pressure sensing means for providing a reference transducer signal indicative of the differential gas pressure P 2 in the reference chamber caused by said volume displacement; and means responsive to the main and reference transducer signals for providing a signal indicative of the gas volume V 1 in the main chamber.