Test instrument and method for isolating and measuring the capacitance due to a particular functional group in a liquid

Claim 2

A liquid test instrument for isolating and measuring the capacitance due to oxygen functional groups in a liquid comprising: a. a sensor including a liquid retaining reservoir with a pair of spaced apart electrodes oriented so liquid contacting surfaces thereof lie in a common plane within said liquid reservoir; b. means connected to said electrodes for applying a relatively high frequency alternating signal between said electrodes; c. electronic means connected to said electrodes for measuring the capacitance therebetween; and d. indicator means connected to said electronic means for indicating any change of capacitance between said electrodes when said reservoir is filled with a liquid to be tested compared with the capacitance when the reservoir is filled with a standard liquid, e. whereby, the indication of a change in capacitance provides a measurement of the capacitance due to oxygen functional groups in said liquid.

Claim 3

A liquid test instrument comprising: a. a sensor including a dish-like liquid reservoir having a liquid capacitance of several drops and a pair of spaced apart electrodes oriented so liquid contacting surfaces thereof lie in a common plane within said reservoir wherein the electrodes form a substantial portion of the bottom thereof; b. means connected to said electrodes for applying a relatively high frequency alternating signal between said electrodes; c. electronic means connected to said electrodes for measuring the capacitance therebetween; and d. indicator means connected to said electronic means for indicating any change of capacitance between said electrodes when said reservoir is filled with a liquid to be tEsted compared with the capacitance when the reservoir is filled with a standard liquid.

Claim 4

A liquid test instrument comprising: a. a sensor including a dish-like liquid reservoir having a liquid capacitance of several drops and a pair of spaced apart electrodes oriented so liquid contacting surfaces thereof lie in a common plane within said reservoir wherein the electrodes form a substantial portion of the bottom thereof; b. means connected to said electrodes for applying a relatively high frequency alternating signal between said electrodes; c. electronic means connected to said electrodes for measuring the capacitance therebetween; and d. indicator means connected to said electronic means for indicating any change of capacitance between said electrodes when said reservoir is filled with a liquid to be tEsted compared with the capacitance when the reservoir is filled with a standard liquid.

Claim 5

A liquid test instrument as set forth in claim 16 wherein the electrodes are spaced apart a distance in the range of approximately 0.001 inches to 0.015 inches.

Claim 6

A liquid test instrument as set forth in claim 3 wherein the electrodes are formed on a substrate and have a thickness in the range of approximately 0.001 inches to 0.02 inches.

Claim 7

A liquid test instrument as set forth in claim 4 wherein the electrodes have a width not less than approximately twice the distance between the electrodes and the length of the gap formed between the adjacent electrodes is in the range of approximately 3 inches to 12 inches.

Claim 8

A liquid test instrument as set forth in claim 16 wherein the electronic means includes a bridge-type circuit with the electrodes of the sensor connected in one leg thereof.

Claim 9

A liquid test instrument as set forth in claim 16 wherein the means connected to apply a frequency to the electrodes includes an electronic oscillator operating at a frequency in the range of approximately 1 to 75 megahertz.

Claim 10

A liquid test instrument for isolating and measuring the capacitance due to oxygen functional groups in a liquid comprising: a. a bridge circuit having inductive components in two adjacent legs thereof and variable capacitance means in one of the remaining legs; b. a pair of spaced apart electrodes, oriented within a liquid-holding reservoir so liquid contacting surfaces thereof lie in a common plane, connected in the remaining leg of said bridge circuit; c. a high frequency oscillator connected across the input of said bridge circuit; and d. a detector circuit and null meter connected across the output of the bridge circuit for indicating any change in capacitance between said electrodes when said reservoir is filled with a liquid to be tested compartd with the capacitance when the reservoir is filled with a standard liquid, e. whereby, the indication of a change in capacitance provides a measurement of the capacitance due to oxygen functional goups in a liquid.

Claim 11

A liquid test instrument for isolating and measuring the capacitance due to oxygen functional groups in a liquid comprising: a. a bridge circuit having inductive components in two adjacent legs thereof and variable capacitance means in one of the remaining legs; b. a pair of spaced apart electrodes, oriented within a liquid-holding reservoir so liquid contacting surfaces thereof lie in a common plane, connected in the remaining leg of said bridge circuit; c. a high frequency oscillator connected across the input of said bridge circuit; and d. a detector circuit and null meter connected across the output of the bridge circuit for indicating any change in capacitance between said electrodes when said reservoir is filled with a liquid to be tested compartd with the capacitance when the reservoir is filled with a standard liquid, e. whereby, the indication of a change in capacitance provides a measurement of the capacitance due to oxygen functional goups in a liquid.

Claim 12

A liquid test instrument as set forth in claim 8 having in addition means surrounding the liquid contacting surfaces of the electrodes for forming a liquid receiving reservoir with a predetermined capacity.

Claim 13

A liquid test instrument as set forth in claim 8 wherein the inductance in series with the variable capacitance is small compared to the remaining inductance and the variable capacitance is large compared to the spaced apart electrodes.

Claim 14

A sensor for isolating and measuring the capacitance due to oxygen functional groups in liquid comprising: a. a substrate formed of an electrical insulating material; b. first and second electrodes of thickness less than 0.02 inches formed on said substrate to provide a uniform elongated gap therebetween of less than 0.015 inches with outwardly directed surfaces thereof lying in a common plane; c. an electrical insulating material filling said gap to form a planar surface with the outwardly directed surfaces, said gap filling material being a relatively low capacitive material; and d. means encompassing the outwardly directed surfaces of said electrodes and the gap therebetween and cooperating with the planar surface to form a liquid retaining reservoir; and e. means connected to said electrodes for comparing the capacitance between said electrodes when said reservoir is filled with a liquid to be tested with the capacitance between said electrodes when said reservoir is filled with a standard liquid.

Claim 15

A sensor for isolating and measuring the capacitance due to oxygen functional groups in liquid comprising: a. a substrate formed of an electrical insulating material; b. first and second electrodes of thickness less than 0.02 inches formed on said substrate to provide a uniform elongated gap therebetween of less than 0.015 inches with outwardly directed surfaces thereof lying in a common plane; c. an electrical insulating material filling said gap to form a planar surface with the outwardly directed surfaces, said gap filling material being a relatively low capacitive material; and d. means encompassing the outwardly directed surfaces of said electrodes and the gap therebetween and cooperating with the planar surface to form a liquid retaining reservoir; and e. means connected to said electrodes for comparing the capacitance between said electrodes when said reservoir is filled with a liquid to be tested with the capacitance between said electrodes when said reservoir is filled with a standard liquid.

Claim 18

A method of testing the degree of oxidation of various liquids as set forth in claim 12 wherein the step of comparing the capacitance includes the step of connecting the sensor in one leg of an electronic bridge circuit having a null meter in the output, zeroing said meter with a standard liquid on the sensor, and determining the meter reading with the liquid to be tested on the sensor.