Measuring instrument for volumetric mass of gas - uses micro-flowmeter to measure pressure between two points difference while chamber is oscillated in rectilinear manner

摘要

Gas flowing in a pipe (10) is leaked through an expansion chamber (11) into a cylindrical chamber (12) from which it exhausts through an outlet pipe (15) and regulator valve (16). The cylindrical chamber is coupled to an exciter (17) which provides rectilinear oscillation for the chamber and its thermally insulated enclosure (22). The temp. within the enclosure is thermostatically controlled. A micro-flowmeter measures pressure difference between two separate points along the path of travel of the chamber in the direction of the action of an oscillating membrane (31) excited by an oscillator (32). This flowmeter uses a wire detector (28) in a bridge circuit (29) whose output is amplified and applied to memories (33,34). An accelerometer (37) measures chamber acceleration and a processing circuit (38) determines the volumetric mass from the acceleration and differential pressure signals.