Fluid dielectric constant comparing device using plural fluid dielectric capacitors alternately connected to a single oscillator

Claim 1

IN APPARATUS OF THE CLASS DESCRIBED FOR DETERMINING THE DIFFERENCE BETWEEN THE DIELECTRIC CONSTANTS OF A REFERENCE FLUID AND THAT OF A FLUID UNDER TEST, THE COMBINATION INCLUDING A PAIR OF SAMPLING CHAMBERS, ONE OF WHICH IS ADAPTED FOR PLACING THEREIN A REFERENCE FLUID AND THE OTHER ADATED FOR PLACING THERIN FLUID UNDER TEST, A PAIR OF TUNING CONDENSERS PLACED RESPECTIVELY IN SAID REFERENCE AND TEST CHAMBERS AND BEING ADAPTED TO HAVE AS THEIR DIELECTRIC SUBSTANCES THE REFERENCE AND TEST FLUIDS RESPECTIVELY, A SINGLE OSCILLATOR HAVING A TUNING CIRCUIT INCLUDING ALTERNATELY ONE OF THE AFOREMENTIONED TURNING CONDENSERS, SWITCH MEANS FOR ELECTRICALLY CONNECTING SAID OSCILLATOR TO ONE OR THE OTHER OF SAID TUNING CONDENSERS AT A GIVEN SWITCHING FREQUENCY, THE CIRCUIT CONSTANTS OF SAID OSCILLATOR AND CONDENSER CIRCUITS BEING ADJUSTED WHEREBY THE OUTPUT FREQUENCY OF THE OSCILLATOR WHEN TUNED BY THE CONDENSER IN THE TEST CHAMBER IS SUBSTANTIALLY EQUAL TO THE FREQUENCY WHEN IT IS TUNED BY THE CONDENSER IN THE REFERENCE CHAMBER WHEN THE FLUIDS IN SAID TWO CHAMBERS ARE IDENTICAL, A FREQUENCY DISCRIMINATOR CONNECTED TO THE OUTPUT OF THE SINGLE OSCILLATOR TO PRODUCE D.C. OUTPUT SIGNALS HAVING INSTANTANEOUS VALUE PROPORTIONAL RESPECTIVELY TO THE OSCILLATOR OUTPUT FREQUENCY AS DETERMINED BY THE VALUE OF THE RESPECTIVE TUNING CONDENSER THEN CONNECTED TO THE OSCILLATOR WHEREBY A SQUARE WAVE OUTPUT SIGNAL OF VARIABLE AMPLITUDE AND PHASE AS DETERMINED BY THE RELATIVE VALUES OF THE TUNING CONDENSERS IS PRODUCED BY THE FREQUENCY DISCRIMINATOR, AND PHASE DETECTOR MEANS DRIVEN AT THE SWITCHING FREQUENCY AND CONNECTED TO THE OUTPUT OF THE FREQUENCY DISCRIMMINATOR TO PRODUCE AN OUTPUT SIGNAL HAVING AN AMPLITUDE EQUAL TO THE DIFFERENCE IN OUTPUT SIGNALS PRODUCED BY SID FREQUENCY DISCRIMINATOR OF SAID GIVEN SWITCHING FREQUENCY.