Measuring device for the mass or mass flow of gas or fluid

Claim 1

AN AREAL TYPE METER COMPRISING A VERTICAL TAPERED PASSAGE THROUGH WHICH A FLUID IS ARRANGED TO FLOW. A SHIELDING PLATE LOCATED IN SAID PASSAGE TO FORM AN ANNULAR ORIFICE BETWEEN SAID PLATE AND SAID PASSAGE, MEANS ELASTICALLY FIXING SAID PLATE WITHIN SAID PASSAGE AGAINST THE FLOW OF SAID FLUID TO CAUSE THE FLOW OF SAID FLUID TO MOVE SAID PLATE ALONG THE AXIS OF SAID PASSAGE AGAINST THE ELASTIC FORCE OF SAID MEANS, A BLADE MOUNTED FOR ROTATION ON SAID PLATE WITHIN SAID PASSAGE, MEANS MOUNTED ON SAID BLADE TO CAUSE THE LATTER TO BE ROTATED BY THE FLOW OF SAID FLUID THROUGH SAID ORIFICE, AND MEANS CONJOINTLY RESPONSIVE TO THE ROTATION AND THE AXIAL POSITION OF SAID BLADE TO MEASURE A TIME PERIOD REQUIRED FOR A POINT ON SAID BLADE TO ROTATE THROUGH AN ANGLE WHICH IS DEPENDENT UPON THE AXIAL DISTANCE BETWEEN SAID POINT ON SAID BLADE AND A POINT ON SAID PASSAGE, THE LAST-MENTIONED MEANS INCLUDING AT LEAST TWO ELONGATED, BELT-SHAPED DETECTORS MOUNTED ALONG SAID PASSAGE IN THE GENERAL DIRECTION OF THE AXIS THEREOF AND CONVERGING AS THEY EXTEND DOWNWARDLY ALONG SAID PASSAGE, SAID ANGLE BEING THE ROTARY ANGLE BETWEEN SAID DETECTORS AND DECREASING PROGRESSIVELY FROM THE UPPER PORTION OF SAID PASSAGE TO THE LOWER PORTION THEREOF, AND AN ELEMENT CARRIED BY SAID BLADE AND PROVIDING AN EFFECT WHICH IS DETECTABLE BY SAID DETECTORS SO THAT SAID TIME PERIOD REQUIRED FOR SAID BLADE TO ROTATE THROUGH SAID ANGLE, FROM A POSITION IN WHICH ONLY ONE OF SAID DETECTORS RESPONDS TO SAID EFFECT OF SAID ELEMENT TO A POSITION IN WHICH ONLY THE OTHER OF SAID DETECTORS RESPONDS TO SAID EFFECT, IS DEPENDENT CONJOINTLY UPON THE SPEED OF ROTATION OF SAID BLADE AND THE AXIAL POSITION OF SAID BLADE ALONG SAID PASSAGE.