Flow rate measuring device

Claim 1

A FLOW RATE MEASURING DEVICE COMPRISING A HOUSING HAVING A BASE AT A FIRST END AND A CLOSURE AT ITS SECOND END, INPUT MEANS FOR INTRODUCING INTO SAID FIRST END OF SAID HOUSING A FLUID TO BE MEASURED AND OUTLET MEANS FOR DISCHARGING SAID FLUID AT SAID SECOND END, PISTON MEANS IN SLIDING CONTACT WITH THE INNER SURFACE OF SAID HOUSING AND MOVABLE IN RESPONSE TO FLUID FLOW BETWEEN SAID FIRST AND SECOND ENDS, MEANS PROVIDING A VARIABLE ORIFICE IN THE INNER SURFACE OF SAID HOUSING COMPRISING A LONGITUDINAL TAPERED GROOVE FORMED EXTENDING GENERALLY IN THE DIRECTION OF PISTON MOVEMENT FROM A BEGINNING POSITION BEYOND THE REARMOST PORTION OF SAID PISTON WHEN SAID PISTON IS POSITIONED NEAREST TO THE FIRST OF SAID ENDS AND INCREASING IN DEPTH FROM ITS BEGINNING POSITION NEAR SAID FIRST END OF SAID HOUSING SURFACE IN THE DIRECTION OF SAID SECOND END, MEANS PROVIDED TO CONNECT SAID TAPERED GROOVE IN FLUID COMMUNICATION WITH FLUID INTROUDUCED INTO SAID FIRST END AS SAID PISTON MOVES TOWARD SAID SECOND END BEFORE THE REARMOST PORTION THEREFORE PASSES THE BEGINNING POSITION OF SAID GROOVE TO RENDER SAID GROOVE COOPERATIVELY OPERATIVE WITH SAID MOVABLE PISTON AND PERMIT VARYING AMOUNTS OF FLUID TO ENTER INTO SAID SECOND END CORRESPONDING TO THE VARIATIONS IN SAID FLOW RATE OF SAID FLUID ENTERING SAID FIRST END; A SENSING INDICATOR HAVING AN ELECTRICAL MEANS INCLUDING AN ELEMENT FIXEDLY POSITIONED AT ONE OF SAID ENDS OF SAID HOUSING AND A VARIABLE ELEMENT ELECTRICALLY ENGAGING SAID FIRST ELEMENT AND POSITIONED ON SAID MOVABLE PISTON.