Oil degradation detection device

Abstract

To provide an oil degradation detection device that can stably and continuously measure over a long period of time. [Solution] The cavity resonator 10 of the oil deterioration detection device 1 has a through hole 11 and a high-frequency hole 12 for passing the liquid to be detected. On one side of the outside of the high-frequency hole 12 of the cavity resonator 10, a first iris 41, a first spacer 51, and a high-frequency emitting circuit 20 are arranged in this order, and on the other side of the outside of the high-frequency hole 12 of the cavity resonator 10, a second iris 42, a second spacer 52, and a high-frequency receiving circuit 30 are arranged in this order. Depending on the degree of deterioration of the liquid passing through the cavity resonator 10, the high-frequency receiving circuit 20 receives a high-frequency signal input from the high-frequency emitting circuit 20 to the cavity resonator 10 and outputs a high-frequency signal from the cavity resonator 10, and detects changes in the frequency and amplitude of the received high-frequency signal compared to when the liquid deterioration has progressed, and obtains information on the degree of liquid deterioration from these changes in frequency and amplitude.

Description

Technical Field

[0001] The present invention relates to an oil deterioration detection device capable of detecting the deterioration state of oil, which detects the deterioration of oil (a state in which the oxidation and hydrolysis states of oil have advanced).

Background Art

[0002] As a method for detecting the deterioration state of oil, there is known a method for detecting the deterioration of an engine of an internal combustion engine using an engine oil deterioration coefficient calculated according to the temperature of the engine oil of the internal combustion engine (for example, Patent Documents 1 and 2). However, it does not directly detect the deterioration of the engine oil, but is merely a method for estimating deterioration.

[0003] There is also a method for detecting the amount of polar compounds in fats and oils using a conversion table indicating deterioration based on the hot water temperature and the current value corresponding to the voltage applied to the fats and oils (for example, Patent Document 3).

[0004] In addition, there are methods for detecting the deterioration of oil from the correlation between the amount of polar compounds and the deterioration of fats and oils. However, this method requires inserting electrodes into the fats and oils and has problems such as risks of ignition (for example, Non-Patent Document 1).

[0005] Furthermore, there is also a method for detecting the deterioration of deep-fried oil using the amount of bubbles generated on the surface of the deep-fried oil as an index (for example, Patent Document 4). Since the invention disclosed in Patent Document 4 is a method for measuring the illuminance on the surface of deep-fried oil using an illuminometer, there is a problem that when used for a long period of time, the light-receiving part of the illuminometer becomes dirty and the error increases.

[0006] In addition to the above, there has been proposed a method for determining the deterioration of lubricating oil from the absorbance or the amount of transmitted light at each wavelength of the lubricating oil using two lights of short wavelength and long wavelength in the range of 0.4 to 2.5 μm (for example, Patent Document 5). However, it is difficult to measure the degree of deterioration of deep-fried oil during frying work due to its structure.

Prior Art Documents

Patent Documents

[0007] [Patent Document 1] Japanese Patent Publication No. 2002-276326 [Patent Document 2] Japanese Patent Publication No. 2002-317615 [Patent Document 3] Japanese Patent Publication No. 2005-55198 [Patent Document 4] Japanese Patent Application Publication No. 8-182624 [Patent Document 5] Japanese Patent Application Publication No. 8-62207 [Non-patent literature]

[0008] [Non-Patent Document 1] Journal of Food Chemistry and Engineering, Vol. 51, No. 1, January 2004, pp. 23-27 [Overview of the project] [Problems that the invention aims to solve]

[0009] Conventional methods for detecting oil degradation present many challenges in terms of being simple and stable. Therefore, the present invention aims to provide an oil degradation detection device that can stably and continuously measure over a long period of time. [Means for solving the problem]

[0010] One aspect of the present invention is, Cavity resonator and, A high-frequency oscillator circuit capable of generating high-frequency signals in the gigahertz range, A high-frequency receiving circuit capable of receiving high-frequency signals in the gigahertz band, A first iris and a first spacer are positioned between the cavity resonator and the high-frequency oscillator circuit, A second iris and a second spacer are positioned between the cavity resonator and the high-frequency receiving circuit, An oil deterioration detection device having means for electrically connecting a high-frequency oscillating circuit and a high-frequency receiving circuit, A cavity resonator has a through-hole for passing the liquid to be detected, and a through-high frequency hole drilled perpendicular to the through-hole. A shield is provided at the opening of the high-frequency hole on the through-hole side to prevent the liquid to be detected from entering. On one of the outer sides of the high-frequency hole of the cavity resonator, the first iris, the first spacer, and the high-frequency oscillator circuit are arranged in this order. On the other side of the high-frequency hole of the cavity resonator, a second iris, a second spacer, and a high-frequency receiving circuit are arranged in this order. This oil degradation detection device works by detecting changes in the frequency and amplitude of the received high-frequency signal compared to when the liquid has degraded, based on the degree of degradation of the liquid passing through the cavity resonator. This is done by a high-frequency receiving circuit that receives a high-frequency signal input from a high-frequency oscillating circuit to the cavity resonator and outputs from the cavity resonator, and obtaining information on the degree of liquid degradation from these changes in frequency and amplitude.

[0011] Conventional oil degradation detection devices had to use a configuration in which a cavity resonator was sandwiched between waveguides. In contrast, the oil degradation detection device of the above configuration uses a high-frequency oscillating circuit and a high-frequency receiving circuit equipped with elements, making it possible to reduce the size of these circuits. Furthermore, by reducing the size of these circuits, it becomes possible to connect them directly to the cavity resonator without using waveguides. Thus, the reduction in size is achieved not only by reducing the size of each circuit, but also by eliminating the need for waveguides that would have been sandwiched between each circuit and the cavity resonator. As a result, a smaller device compared to conventional devices is realized, enabling high-precision detection with a compact device.

[0012] The oil deterioration detection device described above may also include means for detecting the temperature of the oil in the oil deterioration detection device and a table of the relative permittivity of the oil based on its temperature.

[0013] In the oil deterioration detection device as described above, the diameter of the through hole may be in the range of 1 to 10 mm.

[0014] In the oil deterioration detection device as described above, the means for electrically connecting the high-frequency transmission circuit and the high-frequency reception circuit may be a flexible printed circuit board.

[0015] In the oil deterioration detection device as described above, the frequency of the high-frequency signal transmitted from the high-frequency transmission circuit may be 30 to 90 GHz.

[0016] In the oil deterioration detection device as described above, a high-frequency transmission IC may be mounted on the high-frequency transmission circuit.

[0017] In the oil deterioration detection device as described above, a high-frequency reception IC may be mounted on the high-frequency reception circuit.

[0018] In the oil deterioration detection device as described above, the high-frequency transmission IC and the high-frequency reception IC mounted on the high-frequency transmission circuit may be the same IC.

[0019] The oil deterioration detection device as described above may further include means for transmitting alarm information of oil deterioration abnormality to the outside when the deterioration of the oil has progressed more than a predetermined level.

[0020] In the oil deterioration detection device as described above, the relative permeability of the oil may be 2 to 3.

Advantages of the Invention

[0021] According to the present invention, it is possible to provide an oil deterioration detection device that can perform continuous measurement stably and over a long period of time.

Brief Description of the Drawings

[0022] [Figure 1] (A) Plan view, (B) front view, and (C) side view showing an example of the oil deterioration detection device. [Figure 2](A) A plan view, (B) A front view, and (C) A side view are shown, illustrating an example of a cavity resonator that constitutes an oil degradation detection device. [Figure 3] (A) Front view and (B) Side view show examples of shielding structures for cavity resonators in oil degradation detection devices. [Figure 4] This figure shows an example of the circuit board configuration for a high-frequency oscillator circuit and a high-frequency receiver circuit. [Figure 5] This graph shows a comparison of the relative permittivity of oils after undergoing a thermal history. [Modes for carrying out the invention]

[0023] Hereinafter, preferred embodiments of the oil deterioration detection device according to the present invention will be described in detail with reference to the drawings (see Figures 1 to 5).

[0024] The oil degradation detection device 1 described herein is a device for inspecting whether there are any abnormalities due to oil degradation caused by equipment, the surrounding environment, the manufacturing process, etc., targeting liquid samples F such as lubricating oil produced through various manufacturing processes. The oil degradation detection device 1 generates standing waves of electromagnetic waves having a predetermined resonant frequency inside a cavity resonator 10, and the electromagnetic waves are incident on the measurement target F inside the cavity resonator 10. Resonance occurs at a predetermined frequency determined by the dielectric constant of the internal medium and the measurement target F, and the device detects oil degradation by capturing the change in frequency that occurs when oil degradation products with different dielectric constants are present.

[0025] Here, "oil degradation products" refer to oils that have undergone oxidation, hydrolysis, etc. Oxidation is a phenomenon that occurs when oil reacts with oxygen molecules in the air, and is a phenomenon that occurs due to oil degradation. It is sometimes expressed by an index called the "peroxide value." It is accelerated by "light, high temperature, and air," and leads to an increase in viscosity, foaming, and odor generation. Hydrolysis, on the other hand, refers to the breakdown of fatty acids, which are part of the oil molecule, due to water released from food. When oil degrades in this way due to oxidation, hydrolysis, etc., a change occurs in the relative permittivity of the oil, as will be described later. This invention detects and evaluates the degree of oil degradation by capturing this change.

[0026] In this disclosure, electromagnetic waves with a frequency of 3 GHz or higher and less than 30 GHz, and a wavelength of approximately 10 centimeters to 1 centimeter, are referred to as microwaves, and electromagnetic waves with a frequency of 30 GHz or higher and less than 300 GHz, and a wavelength of several millimeters, are referred to as millimeter waves. However, it goes without saying that the distinction between millimeter waves and microwaves is not strictly defined with 30 GHz as the boundary.

[0027] The oil degradation detection device 1 according to this disclosure consists of a cavity resonator 10, a high-frequency oscillating circuit 20, a high-frequency receiving circuit 30, an introduction iris (first iris) 41, an exit iris (second iris) 42, a first spacer 51, a second spacer 52, a flexible printed circuit board (electrical connection means) 60, etc. (see Figure 1, etc.). If it is difficult to directly install the high-frequency oscillating circuit 20 and the high-frequency receiving circuit 30 in the cavity resonator 10 as shown in Figure 1, a waveguide (not shown) may be used between the spacers 51, 52 and the high-frequency oscillating circuit 20 and the high-frequency receiving circuit 30.

[0028] Figure 2 shows a cavity resonator 10. This cavity resonator 10 has a through-hole 11 for passing the oil to be detected, and a high-frequency hole 12 that penetrates the center of the cavity resonator 10 perpendicular to the through-hole 11. A shield 11S is provided to prevent the oil from flowing from the through-hole 11 to the high-frequency hole 12. This shield 11S may be constructed, for example, by inserting a straw structure made of a resin material with a low electrical dielectric constant from the through-hole 11 side, as shown in Figure 3.

[0029] The high-frequency hole 12 contains a medium that readily transmits electromagnetic waves in the resonant frequency band, and in this embodiment, this medium is air. The cavity resonator 10 is configured to generate standing waves within the high-frequency hole 12. The standing waves generated within the high-frequency hole 12 have predetermined resonant frequency components. At least the inner surface of the high-frequency hole 12 is made of metal. In this embodiment, the housing 14 is made of metal walls. Furthermore, as can be seen from the fact that the resonant frequency f for a cavity resonator 10 with the dimensions shown in Figure 2 is expressed by the following equation 1, the smaller the dimensions of the cavity resonator 10 and the lower the dielectric constant of the medium (for example, air in the internal space of the cavity resonator 10), the more the electromagnetic waves generated within the cavity resonator 10 tend to resonate at a higher frequency f. In the equation, ε is the dielectric constant of the medium (dielectric), μ is the permeability of the medium (dielectric), and l, m, and n are the resonant modes.

number

[0030] Here, by reducing dimensions a, b, and c to miniaturize the cavity resonator 10, it is possible to generate a standing wave with a predetermined resonant frequency inside the cavity resonator 10 even when millimeter waves are used, and the electric field strength distribution inside the cavity resonator 10 can be adjusted by the generation of the standing wave. As a result, the amplitude of the standing wave with a predetermined resonant frequency can be increased, that is, the electric field strength can be concentrated and strengthened in a specific range (region). In a cavity resonator 10 configured in this way, when a sample MF containing oil degradation products passes through a range with a relatively strong electric field strength, the range of change in the frequency or intensity of the generated electromagnetic wave becomes larger, and the detection accuracy can be improved.

[0031] As an example, in this embodiment, a cavity resonator 10 is used with dimensions a=3.0mm and b=1.5mm as shown in Equation 1, l=1, m=0, and n=3, i.e., 3 being adopted as the odd number of antinodes of the standing wave, so c=7.2mm. This makes it possible to generate a standing wave with a resonant frequency of 79GHz inside the cavity resonator 10.

[0032] It should be noted that the dimensions a, b, and c above are merely examples, and the dimensions of the cavity resonator 10 can be appropriately adjusted based on the desired electromagnetic waves to be generated inside it. With such an inspection device, even minute changes in the oil degradation state can be detected compared to conventional methods, improving detection accuracy.

[0033] The cavity resonator 10 of this embodiment is composed of a housing 14 comprising one opening 12A through which electromagnetic waves are introduced, a high-frequency hole 12, the other opening 12B through which electromagnetic waves are led out from the high-frequency hole 12, and a through hole 11 through which the sample F passes (see Figure 2, etc.).

[0034] The shape of the housing 14 is not particularly limited, but can be, for example, a rectangular parallelepiped. One opening 12A and the other opening 12B are arranged to face each other inside the high-frequency hole 12. The high-frequency hole 12 is configured such that one or more antinodes, with an odd number of antinodes n, are generated from one opening 12A toward the other opening 12B. As an example, in this embodiment, the number of antinodes n of the standing wave generated inside the high-frequency hole 12 is set to 3, so that the electromagnetic wave resonates in a specific vibration mode.

[0035] The through-hole 11 is provided in the housing 14 of the cavity resonator 10 as a hole through which the sample F to be detected for oil degradation can pass, forming a passage for the sample F to pass through (see Figure 2, etc.). In this embodiment, the through-hole 11 penetrates in a direction Y perpendicular to the direction of propagation X of electromagnetic waves (coinciding with the direction of dimension b, which will be described later). During measurement, the sample F moves from above to below (or from below to above) the through-hole 11 at a predetermined speed and passes through it. That is, the sample F passes through the high-frequency hole 12 of the cavity resonator 10 in the direction of the amplitude of the standing wave generated within the high-frequency hole 12. In this embodiment, a pair of through-holes 11, consisting of an insertion opening into which the sample F is inserted and an outlet opening into which the sample F is discharged, are provided on the widest surface of the housing 14 and its opposite surface, the bottom surface (see Figure 2). It is desirable that the through-hole 11 formed by the pair of communication openings is formed so as to pass through the portion of the standing wave formed inside the cavity resonator 10 where the electric field strength is strong. In other words, the through-hole 11, which is composed of a pair of connecting openings, is preferably formed at a location where the peak of the antinode of the standing wave formed inside the cavity resonator 10 occurs. In this embodiment (not shown), where the number of antinodes n of the standing wave generated inside the through-hole 11 is 3, a pair of through-holes 11 are provided in the central parts of the upper surface 14a and the lower surface of the housing 14, respectively, so that the through-hole 11 passes through the central part of the middle antinode among the three antinodes with strong electric field strength. The diameter of the through-hole 11 is constant so as to generate a standing wave of a high-frequency signal. The diameter of the through-hole 11 is preferably in the range of 1 to 5 mm.

[0036] A shield 11S may be provided around the through-hole 11 to define the through-hole 11. In this embodiment, for example, a shield 11S with a straw structure (hollow structure) made of a material with a relative permittivity of 10 or less is provided to prevent the sample F from entering the high-frequency hole 12 from the through-hole 11 (see Figures 2 and 3). The shield 11S is provided, for example, with a straw-shaped resin with a low dielectric constant to define the boundary with the high-frequency hole 12.

[0037] On one opening 12A side of the housing 14, the input iris (first iris) 41, the first spacer 51, and the high-frequency oscillator circuit 20 are arranged in that order. On the other opening 12B side of the housing 14, the output iris (second iris) 42, the second spacer 52, and the high-frequency receiver circuit 30 are arranged in that order (see Figure 1). The high-frequency oscillator circuit 20, the first spacer 51, and the input iris 41 are fixed to the housing 14 by fixing screws 71, and the high-frequency receiver circuit 30, the second spacer 52, and the output iris 42 are fixed to the housing 14 by fixing screws 72 (see Figure 1).

[0038] Figure 4 shows a circuit block diagram. The high-frequency oscillator circuit 20 is a circuit equipped with an element that emits a high-frequency signal in the gigahertz band. In the oil degradation detection device 1 of this embodiment, the high-frequency oscillator circuit 20 is equipped with a high-frequency oscillator IC 21 that can emit a high-frequency signal in the 60 GHz band, for example (see Figure 3). The frequency of the high-frequency signal emitted from the high-frequency oscillator IC 21 of the high-frequency oscillator circuit 20 may be, for example, 30 to 90 GHz. The high-frequency oscillator circuit 20 further includes a connector 39 for connecting a flexible printed circuit board.

[0039] The high-frequency receiving circuit 30 is a circuit equipped with an element that receives signals emitted from the high-frequency emitting circuit 20 and derived from the cavity resonator 10. The high-frequency receiving circuit 30 in the oil deterioration detection device 1 of this embodiment is equipped with a high-frequency receiving IC 31 as an element that can receive high-frequency signals, and further includes a control microcontroller 32, a power supply IC (not shown), an ADC 33, an alarm indicator LED 34, an operation indicator LED 35, an alarm output port 36, a reset input port 37, a sensitivity adjustment potentiometer 38, and a connector 39 for connecting a flexible printed circuit board (see Figure 4). The control microcontroller 32 controls the circuit by sending and receiving various signals. The operation indicator LED 35 is lit during operation. The output signal port 36 is an output port for outputting an oil deterioration detection signal to the outside when the oil deterioration state is detected. The sensitivity adjustment potentiometer 38 is a device for adjusting threshold information for determining whether or not oil deterioration is present, and the threshold voltage determined by the potentiometer is input to the control microcontroller 32 as digital threshold information via the ADC 33.

[0040] As described above, the oil degradation detection device 1 of this embodiment, which uses high-frequency receiving and transmitting elements (in this embodiment, high-frequency transmitting IC 21 and high-frequency receiving IC 31) in the high-frequency transmitting circuit 20 and high-frequency receiving circuit 30, is easier to miniaturize compared to conventional devices. That is, while conventional oil degradation detection devices 1 had to be configured to sandwich the cavity resonator 10 with waveguides, the oil degradation detection device 1 of the above embodiment uses high-frequency transmitting circuit 20 and high-frequency receiving circuit 30 equipped with elements (in this embodiment, high-frequency transmitting IC 21 and high-frequency receiving IC 31). More specifically, by adopting a circuit equipped with an integrated IC that includes an oscillator, frequency multiplier circuit, frequency divider circuit, signal processing circuit, etc., it is possible to reduce the size of the circuits of these high-frequency transmitting circuit 20 and high-frequency receiving circuit 30. Furthermore, by reducing the size of the circuits of these high-frequency transmitting circuit 20 and high-frequency receiving circuit 30, it becomes possible to connect these circuits directly to the cavity resonator 10 without using waveguides. Incidentally, it might be possible to directly connect the circuits by sandwiching the cavity resonator 10 even if the circuit size is large. However, if the size of the circuits (high-frequency oscillator circuit 20, high-frequency receiver circuit 30) is about the same as the cavity resonator 10 (for example, if the cavity resonator 10 is about 30mm square (a square with sides of about 30mm) and the circuit size is about 30 x 40mm), then no special support for the circuits is necessary. On the other hand, if the circuit is larger than the size of the cavity resonator 10, then a jig to support the circuit board will inevitably be required. In this embodiment, however, by miniaturizing the circuit size of the high-frequency oscillator circuit 20 and the high-frequency receiver circuit 30, the jig mentioned above is not only eliminated, but the waveguide that would have been sandwiched between each circuit and the cavity resonator 10 is also eliminated, contributing to the miniaturization. As a result, a smaller device than conventional devices is realized, and high-precision detection can be performed with a compact device. Note that the high-frequency oscillator IC 21 and the high-frequency receiver IC 31 may be the same IC that has both oscillator and receiver functions.

[0041] The flexible printed circuit board 60 is connected to connectors 29 and 39, electrically connecting the high-frequency oscillator circuit 20 and the high-frequency receiver circuit 30 (see Figure 4). Using such a flexible printed circuit board 60 as a means of electrically connecting the high-frequency oscillator circuit 20 and the high-frequency receiver circuit 30 allows for flexibility in placement and connection, which contributes to miniaturization of the oil degradation detection device 1 as a whole.

[0042] The first spacer 51 is a spacer that prevents the cavity resonator 10 from directly touching the element that outputs a high-frequency signal (high-frequency oscillator IC 21) located on the high-frequency oscillator circuit 20. The second spacer 52 is a spacer that prevents the cavity resonator 10 from directly touching the element that receives a high-frequency signal (high-frequency receiver IC 31) located on the high-frequency receiver circuit 30.

[0043] The introduction iris (first iris) 41 and the derivation iris (second iris) 42 are made of thin metal with a hole in the center and are arranged to sharpen the resonance peak. Ideally, a resonator should be completely surrounded by a metal wall, but when it is necessary to make a hole to allow electromagnetic waves to pass through, as in the case of a cavity resonator 10, if the narrow hole for passing electromagnetic waves is made too long, the electromagnetic waves will not be able to pass through, and the intensity will be greatly reduced due to attenuation. Therefore, it is preferable to make a small hole in the electromagnetic wave input stage of the cavity resonator 10 with a thin metal foil to reduce attenuation. In the oil deterioration detection device 1 of this embodiment, as described above, the high-frequency oscillating circuit 20 and the high-frequency receiving circuit 30 have been miniaturized, making it possible to connect them directly to the cavity resonator 10.

[0044] The operation of the oil degradation detection device 1 configured as described above will now be explained. In the following explanation, a liquid oil sample F will be used as an example, but the sample F targeted by the oil degradation detection device 1 of this embodiment is not limited to this. The oils targeted for detection in this embodiment include, specifically, edible oils, lubricating oils, and the like.

[0045] To detect oil degradation, a high-frequency signal in the 60Hz band is emitted from the high-frequency oscillating circuit 20 and input to the high-frequency hole 12 of the cavity resonator 10 via the first spacer 51 and the introduction iris 41. When a sample F without oil degradation passes through the cavity resonator 10 (through hole 11), the input frequency is shifted from 60GHz by the difference between the dielectric constant ε1 of the sample F and the dielectric constant of air, as shown in Equation 1, and input to the high-frequency receiving circuit 30 via the derivation iris 42 and the second spacer 52.

[0046] Here, we will use Figure 5 to explain the effect of oil degradation on the dielectric constant. When frying oil is subjected to a thermal history, it was found that a significant difference in relative permittivity was clearly visible when measured using a cavity resonator. Based on this finding, the present invention detects changes in the relative permittivity of oil by interpreting them as oil degradation.

[0047] Next, when the degraded oil sample F enters the cavity resonator 10, the frequency changes significantly from 60 GHz because the dielectric constant of the degraded oil is significantly different from that of the undegraded oil. This change is detected by the high-frequency receiving IC 31 or the control microcontroller 32, which determines that oil degradation has been detected. When oil degradation is detected, the output signal port 36 is activated to output to an external control device (not shown), etc.

[0048] The embodiments described above are merely examples of preferred implementations of the present invention, and are not limited thereto. Various modifications are possible without departing from the spirit of the invention. For example, the embodiments described above describe a case where the element 21 (31) mounted on the high-frequency oscillator circuit 20 (high-frequency receiver circuit 30) is a high-frequency oscillator IC 21 (high-frequency receiver IC 31), that is, a multifunctional device. However, this is merely one preferred example, and it goes without saying that circuits with so-called discrete components (individual electronic components, etc.) mounted on them may be used instead. [Industrial applicability]

[0049] The present invention is suitable for application to an oil degradation detection device. [Explanation of symbols]

[0050] 1… Oil degradation detection device 10...Cavity resonator 11…Through-hole 11S...Shield 12… High-frequency holes 12A... One opening 12B... The other opening 14…Cabinet 14a…Top surface 20…High-frequency oscillator circuit 21…High-frequency oscillator IC (device) 29… Connector 30…High-frequency receiving circuit 31…High-frequency receiving IC (element) 32... Microcontroller for control 33…ADC 35… LED for operation indicator 36…Output signal port 38... Sensitivity adjustment volume 39… Connector 41... Introduction Iris (First Iris) 42... Derived Iris (Second Iris) 51…First spacer 52…Second spacer 60… Flexible printed circuit board (electrical connection means) 71… Fixing screws 72… Fixing screws F... Specimen

Claims

1. Cavity resonator and, A high-frequency oscillator circuit capable of generating high-frequency signals in the gigahertz range, A high-frequency receiving circuit capable of receiving high-frequency signals in the gigahertz band, A first iris and a first spacer are disposed between the cavity resonator and the high-frequency oscillator circuit. A second iris and a second spacer are disposed between the cavity resonator and the high-frequency receiving circuit. An oil deterioration detection device having means for electrically connecting the high-frequency oscillating circuit and the high-frequency receiving circuit, The cavity resonator has a through hole for passing the liquid to be detected, and a through-high frequency hole drilled perpendicular to the through hole. A shield is provided at the opening of the high-frequency hole on the through-hole side to prevent the liquid to be detected from entering. On one of the outer sides of the high-frequency hole of the cavity resonator, the first iris, the first spacer, and the high-frequency oscillator circuit are arranged in this order. On the other side of the cavity resonator, outside the high-frequency hole, the second iris, the second spacer, and the high-frequency receiving circuit are arranged in this order. An oil degradation detection device that, depending on the degree of degradation of the liquid passing through the cavity resonator, detects changes in the frequency and amplitude of the received high-frequency signal compared to when the liquid has degraded, using a high-frequency receiving circuit that receives a high-frequency signal input from the high-frequency oscillating circuit to the cavity resonator and outputs from the cavity resonator, and obtains information on the degree of liquid degradation from these changes in frequency and amplitude.

2. The oil deterioration detection device according to claim 1, characterized in that it comprises means for detecting the temperature of the oil in the oil deterioration detection device and a dielectric constant table of the oil based on the oil temperature.

3. The oil deterioration detection device according to claim 1, characterized in that the diameter of the through hole is in the range of 1 to 10 mm.

4. The oil degradation detection device according to claim 1, characterized in that the means for electrically connecting the high-frequency oscillating circuit and the high-frequency receiving circuit is a flexible printed circuit board.

5. The oil deterioration detection device according to claim 1, characterized in that the frequency of the high-frequency signal emitted from the high-frequency oscillator circuit is in the 30 to 90 GHz range.

6. The oil deterioration detection device according to claim 1, characterized in that a high-frequency oscillator IC is mounted in the high-frequency oscillator circuit.

7. The oil deterioration detection device according to claim 1, characterized in that a high-frequency receiving IC is mounted in the high-frequency receiving circuit.

8. The oil degradation detection device according to claim 1, characterized in that the high-frequency transmitting IC and the high-frequency receiving IC mounted in the high-frequency oscillating circuit are the same IC.

9. The oil deterioration detection device according to claim 1, characterized in that it has means for transmitting an alarm information about an abnormal oil deterioration to an external source when the oil deterioration progresses beyond a predetermined level.

10. An oil deterioration detection device according to any one of claims 1 to 9, characterized in that the relative permeability of the oil is 2 to 3.

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