Electricity: measuring and testing – Impedance – admittance or other quantities representative of... – Lumped type parameters
Patent
1993-09-14
1995-10-10
Wieder, Kenneth A.
Electricity: measuring and testing
Impedance, admittance or other quantities representative of...
Lumped type parameters
324 714, 324698, 340631, G01N 2706
Patent
active
054573963
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD OF THE INVENTION
This invention relates to an electrode structure of a sensor for detecting metallic particles mixed in a liquid such as lubrication oil.
BACKGROUND TECHNOLOGY OF THE INVENTION
Conventionally, as means for detecting presence or absence of metal powders floating in a lubrication oil, there is known means for detecting the mixing of the metal powders by adsorbing the metal powders by a magnet disposed, for example, on a bottom wall of an oil tank and detecting the change of magnetic flux at this time.
In the above conventional floating metal powder detecting means, the detecting means are disposed in a spot-like manner to the oil tank, and the detecting ability of one detecting means is limited. Accordingly, when it is required to perform the detection over a wide range, the provision of a large number of detecting means is inevitably required. The increasing of the location positions of the detecting means results in a problem of complicated detecting control thereof. Furthermore, in the above conventional detecting means, it is impossible to utilize the detecting means in a case where the metal powder is small in size and its mixed amount is relatively small such as several tens to several thousands PPM.
SUMMARY OF THE INVENTION
This invention was conceived in view of the above facts the object thereon is to provide an electrode structure of a metallic particle detecting sensor capable of detecting metal powders floating over a wide range of an oil tank, and detecting the metal powders with high efficiency even in a case where the metal powder is small in size and its mixed amount is relatively small.
To achieve the above object, the electrode structure of the metallic particle detecting sensor according to this invention has a structure wherein a pair of electrodes, each being formed of a thin film metal, is formed on an insulation substrate in a state that the electrodes are opposed to each other and have combed, interdigitated structures.
Furthermore, the electrodes are opposed with a distance (spacing) of 1 to 50 .mu.m therebetween and each of said electrodes has a width 3 to 8 times of the opposing distance (spacing).
The thin film metal forming the electrodes may consists of a metal of Ta, W, Pt, Cr, Au or the like which does not constitute an insulator or semiconductor even when the thin film metal becomes an oxide.
In the electrode structure described above, when the metal powders exist between both of the electrodes with electric voltage of 30 - 50V being applied between the electrodes, a pulse voltage is generated between the end portions of the electrodes and this pulse voltage is detected.
According to this invention, since the metallic particle detecting sensor having a wide area in a plane can be manufactured, it is possible to detect the metal powders floating over a wide range of an oil tank and it is also possible to detect with high efficiency the floating metal powders even in a case where a small amount of the metal powders floats and its mixed amount is relatively small.
Furthermore, according to this invention, a mass production of the detection sensors can be done at once due to its structure and the combined detection of such as temperatures can be easily done. Furthermore, since the detection sensor can be formed so as to provide a curved surface, its application for the usage thereof can be widened. Still further, since the specific heat is small and the time up to the temperature balance is short, the follow-up characteristic to a temperature change of the lubrication oil is good and a stable detection result can be achieved in spite of a temperature change of the lubrication oil.
The above and other objects, modes and advantages of this invention will be made clear to those skilled in the art by the following description and explanation made with reference to the accompanying drawings showing concrete examples as embodiments in compliance with the principle of this invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic plan v
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IBM Technical Disclosure Bulletin, vol. 26, No. 5, Oct., 1983, New York, USA, pp. 2606-2607, J. Harper et al, Particle Detector.
Hirosawa Atsuhiko
Mori Akira
Uchino Ikuo
Yamasaki Kunihiro
Do Diep
Kabushiki Kaisha Komatsu Seisakusho
Wieder Kenneth A.
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