Gas concentration-detecting device for detecting concentration of gas in oil

A gas concentration-detecting device for detecting a concentration of gas in oil, comprising:

• an outer electrode portion comprising an outer hollow casing and a first electrode fitted in a first end of the outer hollow casing, said outer hollow casing comprising a side wall formed with a slit;
• a first lead wire electrically connected to the outer electrode portion;
• an inner electrode portion comprising an inner hollow casing and a second electrode fitted in a first end of the inner hollow casing, said inner electrode portion mounted in the outer electrode portion, such that the first electrode is opposed to and spaced from the second electrode by a predetermined distance;
• a second lead wire electrically connected to the inner electrode portion;
• and
• a gas concentration detector for outputting a signal indicative of said concentration of said gas in said oil, said signal being dependent on a capacitance between said electrodes,
• wherein said slit provides access to a space between the first and second electrodes and said predetermined distance between said electrodes is set to a value equal to or larger than a predetermined value at which an amount of drift of said signal output from said gas concentration detector dependent on variation in a temperature of said oil starts to gradually decrease as a distance between said electrodes is increased.

A method of detecting a concentration of gas in oil, comprising the steps of:

• providing a gas-concentration detecting device, comprising a plurality of electrodes being opposed to each other and spaced from each other by a predetermined distance and a gas concentration detector for outputting a signal indicative of said concentration of said gas in said oil, said signal being dependent on a capacitance in said oil;
• arranging the electrodes in a supply of oil, such that the alectrodes are opposed to each other and spaced from each other by a predetermined distance, wherein said predetermined distance between the electrodes is set to a value equal to or larger than a predetermined value at which an amount of drift of said signal output from said gas concentration detector dependent on vacation in a temperature of said oil starts to gradually decrease as a distance between said electrodes is increased;
• measuring a capacitance between the electrodes using the gas-concentration detector;
• and
• correlating the capacitance in the oil to the concentration of the gas in the oil.

A gas concentration-detecting device for detecting a concentration of gas in oil, comprising:

• a plurality of electrodes for being arranged in said oil such that said electrodes are opposed to each other and spaced from each other by a predetermined distance;
• and
• gas concentration detector for outputting a signal indicative of said concentration of said gas in said oil, said signal being dependent on a capacitance between said electrodes,
• wherein said predetermined distance between said electrodes is between about one millimeter and about five millimeters, such that an amount of drift of said signal output from said gas concentration detector dependent on variation in a temperature of said oil starts to gradually decrease as a distance between said electrodes is increased.

A gas concentration-detecting device for detecting a concentration of gas in oil, comprising:

• a plurality of electrodes for being arranged in said oil such that said electrodes are opposed to each other and spaced from each other by a predetermined distance to form an open space therebetween;
• and
• gas concentration detector for outputting a signal indicative of said concentration of said gas in said oil, said signal being dependent on a capacitance between said electrodes,
• means for setting the predetermined distance between said electrodes to a value equal to or larger than a predetermined value at which an amount of drift of said signal output from said gas concentration detector dependent on variation in a temperature of said oil starts to gradually decrease as a distance between said electrodes is increased.

A gas concentration-detecting device for detecting a concentration of gas in oil, comprising:

• a plurality of electrodes for being arranged in said oil such that said electrodes are opposed to each other and spaced from each other by a predetermined distance to form an open space therebetween;
• and
• gas concentration detector for outputting a signal indicative of said concentration of said gas in said oil, said signal being dependent on a capacitance between said electrodes,
• wherein said predetermined distance between said electrodes is set to a value equal to or larger tan a predetermined value at which an amount of drift of said signal output from said gas concentration detector dependent on variation in a temperature of said oil stars to gradually decrease as a distance between said electrodes is increased.