Flowmeter

Claim 1

A FLOWMETER COMPRISING A CASING HAVING A CHAMBER WITHIN, INLET AND OUTLET PASSAGES FOR SAID CHAMBER, A NOZZLE CONNECTED TO THE INLET PASSAGE AND DISCHARGING INTO THE CHAMBER, SAID NOZZLE HAVING ITS DOWNSTREAM END OUTER WALLS TAPERED INWARDLY TO INTERSECT THE NOZZLE BORE AT AN ACUTE ANGLE SO AS TO TERMINATE THE NOZZLE WITH A SHARP EDGE, A PLATE LARGER IN AREA THAN THE CROSS-SECTIONAL AREA OF THE NOZZLE, SAID PLATE BEING MOUNTED IN A PLANE SUBSTANTIALLY NORMAL TO THE NOZZLE AXIS AND MOVABLE TOWARD AND AWAY FROM THE NOZZLE IN RESPONSE TO VARIATIONS IN FLUID FLOW THERETHROUGH TO PROVIDE A VARIABLE ORIFICE BETWEEN THE PLATE AND THE SHARP EDGE OF THE NOZZLE, A SPRING FOR URGING THE PLATE TOWARD THE NOZZLE WITH SUBSTANTIALLY CONSTANT FORCE OVER THE RANGE OF MOVEMENT OF THE PLATE, COUNTERBALANCE MEANS CONNECTED WITH THE PLATE TO RENDER THE RESTORING FORCE ON THE PLATE SUBSTANTIALLY INDEPENDENT OF GRAVITY, MEANS FOR INDICATING THE SPACING BETWEEN PLATE AND NOZZLE UPON THE FLOW OF FLUID THEREBETWEEN, AND MEANS FOR LIMITING THE MOVEMENT OF THE PLATE FROM THE NOZZLE TO A DISTANCE APPROXIMATELY ONEEIGHTH THE DIAMETER OF THE NOZZLE TO PROVIDE A SUBSTANTIALLY LINEAR RELATION BETWEEN FLUID FLOW RATE AND ORIFICE OPENING.