Apparatus for measuring the mass flow of fluids

Claim 1

A MASS-FLOW METERING DEVICE COMPRISING: STATIONARY DEFLECTOR MEANS ARRANGED IN A DUCT TO IMPART TO FLUID FLOWING ALONG THE DUCT A SWIRL ABOUT THE AXIS OF THE DUCT, SAID DEFLECTOR MEANS INCLUDING VANES WHICH ARE ADJUSTABLE AS TO THEIR ANGLE OF ATTACK WITH RESPECT TO THE AXIAL DIRECTION OF THE DUCT; RATE-SENSOR MEANS PRODUCING A DIGITAL OUTPUT CORRESPONDING TO THE RATE OF SWIRL THUS PRODUCED; TORQUESENSOR MEANS DETERMINING A TORQUE REACTION PRODUCED BY THE THUS PRODUCED SWIRL OF THE FLUID FLOWING THROUGH THE DUCT AND PRODUCING A DIGITAL OUTPUT CORRESPONDING TO THE SAID TORQUE REACTION; DIGITAL COMPUTER MEANS PRODUCING A DIGITAL OUTPUT, MEANS FEEDING TO SAID COMPUTER MEANS THE RESPECTIVE DIGITAL OUTPUTS OF THE RATE-SENSOR MEANS AND OF THE TORQUE-SENSOR MEANS, THE COMPUTER MEANS BEING CONSTRUCTED TO DETERMINE THE MASS FLOW AS THE QUOTIENT OF SAID DIGITAL OUTPUTS; A SERVOMOTOR OPERATIVELY CONNECTED TO THE DEFLECTOR MEANS TO VARY THE ANGLE OF ATTACK OF THE DEFLECTOR VANES WITH RESPECT TO THE AXIAL DIRECTION OF THE DUCT; AND CONTROL MEANS INCLUDING AN ALGEBRAIC ADDER SERVOMOTOR-CONTROL MEANS INCLUDING AN ALGEBRAIC ADDER TO WHICH THE DIGITAL OUTPUTS OF THE COMPUTER MEANS AND OF THE RATE SENSOR ARE DIFFERENTIALLY FED, AND MEANS SENSITIVE TO THE SIGN OF THE ADDER OUTPUT AND OPERATIVE TO SELECT THE DIRECTION OF OPERATION OF THE SERVOMOTOR.