JP2003215040A - State detector for lubricating oil in refrigerating cycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect a state of a lubricating oil in a refrigerating cycle with satisfactory accuracy by using a compact and low-cost detector. <P>SOLUTION: The state detector for the lubricating oil in the refrigerating cycle is provided with a plurality of optical fibers 15, 16A, 16B and so on which are installed in parallel inside fixation members 14 of an airtight and pressure- resistant structure, light sources 17 and light receiving parts 18A, 18B and so on which are connected to the optical fibers 15, 16A, 16B and so on and decision means 19 which decide the state of the lubricating oil on the basis of beams of light received by the light receiving parts 18A, 18B and so on. The state detector is constituted in such a way that beams of light from the light sources 17 are irradiated at the lubricating oil via the optical fibers 15 and that light from a coloring agent added to the lubricating oil is received by the light receiving parts 18A, 18B and so on via the optical fibers 16A, 16B and so on. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating oil state detection device in a refrigeration cycle.

[0002]

2. Description of the Related Art For example, a refrigerating cycle shown in FIG. 1 is constructed by connecting a compressor 1, a condenser 2, a pressure reducing mechanism 3 and an evaporator 4 in order by refrigerant pipes 5, 6, 7 and 8.

In the refrigeration cycle having the above structure, the lubricating oil circulates together with the refrigerant. However, the lubricating oil in the compressor is diluted with the liquid refrigerant, and the viscosity of the lubricating oil decreases, resulting in poor lubrication. When the lubricating oil foams in the compressor, the lubricating oil cannot be sucked up by the oil pump for supplying the lubricating oil to the compressor, and the lubricating oil flows out from the compressor due to the transient operating state. The decrease in the oil level in the oil sump causes seizure of the compressor, which causes a problem that the refrigeration cycle cannot operate.

Therefore, measures have been conventionally taken to prevent the seizure of the compressor by detecting the state of the lubricating oil in the refrigeration cycle (for example, the degree of dilution, the foaming state or the oil level drop).

For example, a flow rate detecting device for detecting the flow rates of lubricating oil and refrigerant is provided in the suction pipe between the evaporator and the compressor (see Japanese Patent Laid-Open No. 10-288431).

In the above-mentioned flow rate detecting device, the first light-transmitting portion which makes the light from the light source enter the light-transmitting cylindrical member coaxially connected to the suction pipe, and the lubricating oil flowing inside the light-transmitting cylindrical member is the first light-transmitting portion. (1) A second light-transmitting portion that emits fluorescence emitted by receiving light incident from the light-transmitting portion to the outside of the suction pipe, and the flow rate of the lubricating oil is detected as the amount of fluorescence emitted from the second light-transmitting portion. And a fluorescence amount detecting means.

[0007]

However, in the case of the above-mentioned flow rate detecting device, since the refrigerant flowing in the light-transmitting cylindrical member has a low pressure and low temperature, dew condensation may occur on the outside of the light-transmitting cylindrical member. Light and the fluorescence emitted from the inside are blocked by dew condensation, which causes a problem that a detection error increases. In addition, since the light incident from the first light transmitting portion and the fluorescence emitted from the second light transmitting portion need to have a predetermined angle, the device itself must be large. . Furthermore, there is also a problem that highly accurate optical axis adjustment and highly accurate light-transmissive cylindrical member processing are required. In addition, there was no proper detecting means for detecting the state of the lubricating oil in the oil sump of the compressor.

The present invention has been made in view of the above points, and an object of the present invention is to make it possible to accurately detect the state of lubricating oil in a refrigeration cycle with a compact and low-cost device. .

[0009]

According to the invention of claim 1, as means for solving the above-mentioned problems, a compressor 1, a condenser 2, a pressure reducing mechanism 3 and an evaporator 4 are sequentially connected by refrigerant pipes 5-8. And a plurality of optical fibers 15, 16A, 16B, ... Installed in parallel in the fixing member 14 of the airtight pressure-proof structure, and Fiber 15,1
Light source 17 and light receiving section 1 connected to 6A, 16B
8A, 18B ... And a judging means 19 for judging the state of the lubricating oil from the light received by the light receiving portions 18A, 18B .., and the light from the light source 17 is lubricated through the optical fiber 15. The oil is irradiated, and the light from the colorant added to the lubricating oil is received by the light receiving portions 18A, 18B ... Through the optical fibers 16A, 16B.

With the above construction, the plurality of optical fibers 15, 16A, 16B, ... Installed in parallel in the fixing member 14 having the airtight pressure-proof structure, and the optical fiber 1
The light source 17 and the light receiving parts 18A, 18B ... Connected to the light receiving parts 18A, 18B.
Since the structure is provided with the judging means 19 for judging the state of the lubricating oil from the received light, it is possible to have a compact structure without requiring a high degree of machining accuracy, and due to a mounting error. There is no need to worry about noise due to sensitivity changes or vibration. Moreover, the light from the light source 17 is irradiated onto the lubricating oil through the light source side optical fiber 15, and the light from the colorant added to the lubricating oil is irradiated with the light source side optical fiber 15.
Since the light receiving portions 18A, 18B ... Are received through the light receiving portion side optical fibers 16A, 16B.

As in the invention of claim 2, claim 1
In the lubricating oil state detection device in the refrigeration cycle described above, the light receiving unit side optical fibers 18A, 18B ...
In order to selectively observe the space Y ₁ , Y ₂ ··· where the visual field X ₀ from the light source side optical fiber 15 and the visual fields X ₁ , X ₂ ··· of the light receiving portion optical fibers 18A, 18B · · intersect. In the case of the configuration, information existing in the spaces Y ₁ , Y ₂ ··· where the visual field X ₀ from the light source side optical fiber 15 and the visual fields X ₁ , X ₂ ··· of the light receiving unit optical fibers 16A, 16B · · intersect. That is, the light intensity) can be detected, and the state change of the lubricating oil can be accurately detected.

As in the invention of claim 3, claim 1
In the lubricating oil state detection device in the refrigeration cycle according to any one of 1 and 2, the determination means 19 is provided while being provided in the bottom portion of the compressor 1 or in the suction pipe 8 between the evaporator 4 and the compressor 1. The light receiving portion 18A,
When the function of detecting the dilution degree of the lubricating oil from the change of the DC value component of the intensity signal of the light received by 18B ... Is provided, the light intensity signals of the light received by the light receiving portions 18A, 18B. Since the degree of dilution of the lubricating oil can be detected from the change in the DC value component, it is possible to predict the decrease in the viscosity of the lubricating oil.

As in the invention of claim 4, claim 1
3. The lubricating oil state detection device in the refrigeration cycle according to any one of 1 and 2 above, wherein the evaporator 4 and the compressor 1 are provided.
Is provided in the suction pipe 8 between
A, 18B ... Has two types of light receiving elements sensitive to the light from the colorant and other wavelength bands, and measures the oil amount and the mist-like liquid refrigerant amount by comparing the light intensities. In the case of a configuration having a function of, the amount of oil and the amount of mist-like liquid refrigerant can be measured respectively by comparing the light intensities received by the light receiving portions 18A, 18B, ... And the amount of liquid refrigerant can be known individually.

According to the invention of claim 5, in the lubricating oil state detecting device in the refrigerating cycle according to any one of claims 1, 2, 3 and 4, the light receiving section side optical fibers 16A, 16B ... When the optical path refraction member 32 for moving the detection area is provided at the tip of the, the field of view of the light-receiving side optical fibers 16A, 16B ... Can be freely adjusted, and the installation location can be freely selected.

According to a sixth aspect of the present invention, in the lubricating oil state detecting device in the refrigerating cycle according to any one of the first, second, third, fourth and fifth aspects, the lubricating oil state detecting apparatus is provided at the bottom of the compressor 1. When the determination means 19 is configured to have a function of detecting foaming of the lubricating oil by selecting an arbitrary frequency component from the AC value component of the intensity signal of the light received by the light receiving portions 18A, 18B ... , Light receiving unit 18
A foaming of the lubricating oil can be detected by selecting an arbitrary frequency component from the AC value component of the intensity signal of the light received by A, 18B ..., It is possible to predict the insufficient supply of the lubricating oil to the compressor 1. .

According to the invention of claim 7, in the lubricating oil state detecting device in the refrigerating cycle according to any one of claims 1, 2, 3, 4, 5 and 6, a side surface of the compressor 1 is provided. The determination means 19 is provided at the oil level lower limit set height position P and the light receiving portion 18A,
When the function of detecting the oil level drop of the lubricating oil is detected from the presence or absence of the DC value component of the intensity signal of the light received by 18B ..., The intensity signal of the light received by the light receiving parts 18A, 18B. It is possible to detect a decrease in the oil level of the lubricating oil based on the presence or absence of the DC value component of, and it is possible to predict the insufficient supply of the lubricating oil to the compressor 1.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in FIG. 1, this lubricating oil state detecting device A connects a compressor 1, a condenser 2, a pressure reducing mechanism 3 and an evaporator 4 in order by means of refrigerant pipes 5, 6, 7 and 8. The compressor 1 is applied to the configured refrigeration cycle.
Is provided at the bottom of the oil tank, the oil surface lower limit set height position on the side surface of the compressor 1, or the suction pipe 8 between the evaporator 4 and the compressor 1.

First, as shown in FIG. 2, at the bottom of the closed casing 9 of the low-pressure dome type hermetic compressor 1 (that is, the bottom of the oil sump 10), the oil pump 11 (also used as the rotary shaft of the compressor). A case where the lubricating oil state detection device A is provided at a position facing the suction port 11a and the oil surface lower limit set height position P on the side surface of the closed casing 9 will be described. Reference numeral 12 is a compression unit, and 13 is a motor unit.

As shown in FIGS. 3 and 4, the state detecting device A includes a plurality of optical fibers 15, 16A, 16B arranged in parallel in a fixing member 14 having an airtight pressure resistant structure, and the optical fibers 15, 16A, 16B. Light source 17 connected to 16A and 16B
And light receiving portions 18A and 18B, and the light receiving portions 18A and 18B
A circuit board 19 which functions as a judging means for judging the state of the lubricating oil from the light received by B.
Lubricating oil is radiated from the light source 7 through the light source side optical fiber 15, and the light from the oil-soluble colorant added to the lubricating oil is passed through the light receiving unit side optical fibers 16A and 16B. The light receiving portions 18A and 18B are configured to receive light, respectively. In the present embodiment, a fluorescent agent used for refrigerant leakage detection is adopted as the colorant, and the fluorescent agent emits fluorescence upon receiving light from the light source 17. . Therefore, in the present embodiment, the light receiving portions 18A and 18B receive the fluorescence from the fluorescent agent, but when a coloring agent that does not emit fluorescence is adopted, the light receiving portions 18A and 18B are colored. The reflected light from the agent will be received.

Optical fibers 16A and 16B on the light receiving portion side
Is the space Y ₁ , Y ₂ (the space shaded in FIG. 3) where the field of view X ₀ from the light source side optical fiber 15 and the fields of view X ₁ and X ₂ of the light receiving side optical fibers 16A and 16B intersect. It is configured to observe. Since it is configured as described above, it is possible to have a compact structure without requiring a high degree of machining accuracy, and there is no fear of noise change due to sensitivity change or vibration due to mounting error. Moreover, the light from the light source 17 is applied to the lubricating oil through the optical fiber 15 on the light source side, and the light (for example, fluorescent light) from the coloring agent (for example, fluorescent agent) in the lubricating oil is irradiated on the light source side optical fiber 15.
Since the light receiving portions 18A and 18B receive light through the light receiving portion side optical fibers 16A and 16B which are parallel to the light receiving portion side optical fibers 16A and 16B, it is not necessary to perform highly accurate optical axis adjustment.

Now, a mode of detecting the state of the lubricating oil by the above-mentioned state detecting device A will be described with reference to FIG.

FIG. 5 is a schematic diagram of a signal processing system from the state detecting device A, and shows a circuit board 19 as a judging means.

Light receiving portions 18A, 1 in the state detecting device A
The signal from 8B is amplified by the amplifiers 20A and 20B to be, for example, signal waveforms a and b. In these signal waveforms a and b, when the lubricating oil is not foaming (that is, when forming is not occurring), only the DC component of the concentration transition is shown as a. When B is foaming (that is, when forming is occurring), it becomes a pulsating AC component as indicated by B.

These signal waveforms a and b are added to the confluence point P ₁ to obtain a signal waveform c, which is filtered by the bandpass filter 21 to form a signal waveform d.
The signal waveform e is obtained by 2 and is filtered by the low-pass filter 23 to obtain the signal waveform f. In the signal waveform f, the AC components are averaged to show that forming is occurring.

The forming determination can be performed only by the signal from the light receiving portion 18B, the signal waveform b is filtered by the bandpass filter 24, and the rectifying circuit 25 is used.
After that, it may be filtered by the low-pass filter 26.

On the other hand, the signal waveform from the light receiving portion 18A can be filtered by the low-pass filter 27 to obtain a signal waveform g, and the oil concentration can be detected by the light intensity-oil concentration conversion table 28. Further, by binarizing the result obtained by the light intensity-oil concentration conversion table 28, it is possible to determine whether the oil level is lower than the oil level lower limit height from the presence or absence of the light intensity signal. .

Further, the signal waveforms from the light receiving portions 18A and 18B may be added at the confluence point P ₂ , filtered by the low pass filter 29, and then the oil concentration may be detected by the light intensity-oil concentration conversion table 30.

In other words, the state detecting device A has the light receiving section 1
The function of detecting the dilution degree of the lubricating oil from the change in the direct current value component of the intensity signal of the light (for example, fluorescence) received by 8A and 18B, and the light received by the light receiving units 18A and 18B (for example,
A function of selecting an arbitrary frequency component from the AC value component of the intensity signal of (fluorescence) and detecting the foaming of the lubricating oil;
It has a function of detecting a decrease in the oil level of the lubricating oil based on the presence or absence of a DC value component of the intensity signal of the light (for example, fluorescence) received by A and 18B.

Next, the case where the state detecting device A is installed in the suction pipe 8 will be described.

In this case, as shown in FIGS.
A flow path narrowing member 31 for narrowing the flow path is provided in the middle of the suction pipe 8, and the state detection device A is attached to the flow path narrowing member 31. The reason for doing this is that the refrigerant flowing through the suction pipe 8 is a gas refrigerant and the lubricating oil has an annular flow along the pipe wall, so that the lubricating oil is moved to the center of the flow path and detected by the state detection device A. This is to facilitate

In this case, since foaming of the lubricating oil does not occur,
Only the change in the concentration of the lubricating oil will be detected.

When the pipe diameter of the suction pipe 8 is small, there may be a case where the visual field X ₀ from the optical fiber 15 on the light source side and the visual fields X ₁ and X ₂ on the optical fibers 16A and 16B on the light receiving side cannot cross each other. However, in that case, as shown in FIGS. 9 to 11, as shown in FIGS.
An optical path refraction member (for example, prism 32) for moving the detection area may be provided at the tip of 16B. In this way, the field of view of the light-receiving side optical fibers 16A and 16B can be freely adjusted, and the installation location can be freely selected.

If the fluorescence intensity transmitted in the opposite direction through the light source side optical fiber can be detected, the thickness of the oil film formed on the end face of the light source side optical fiber can be measured. is there.

Further, the lubricating oil containing the colorant may be irradiated with light in a wavelength band that is difficult to be absorbed and scattered. In that case, the amount of liquid refrigerant can be detected at the same time from the intensity of backscattered light.

In this case, the light receiving portions 18A, 18B ...
Has two kinds of light receiving elements sensitive to the light from the colorant and other wavelength bands, and has a function of measuring the amount of oil and the amount of mist-like liquid refrigerant by comparing the light intensities, respectively. It can also be configured. In that case, the amount of oil and the amount of mist-like liquid refrigerant can be measured by comparing the light intensities received by the light receiving portions 18A, 18B, ... You can know it individually.

Further, the state detection device A may be composed of an optical integrated element in which an optical fiber, a light source and a light receiving section are integrally molded.

[0038]

According to the first aspect of the present invention, the compressor 1, the condenser 2, the decompression mechanism 3 and the evaporator 4 are sequentially arranged in the refrigerant pipes 5 to 5.
A plurality of optical fibers 15, 16A, 16B, ... Installed in parallel in the fixing member 14 of the airtight pressure resistant structure, with the lubricating oil state detecting device in the refrigerating cycle provided at appropriate places in the refrigerating cycle , The optical fiber 1
The light source 17 and the light receiving parts 18A, 18B ... Connected to the light receiving parts 18A, 18B.
A determination means 19 for determining the state of the lubricating oil from the light received by the light source, irradiating the lubricating oil with the light from the light source 17 through the optical fiber 15, and coloring the lubricating oil. Since the light from the agent is received by the light receiving portions 18A, 18B, ... Through the optical fibers 16A, 16B, .. In addition, there is an effect that there is no fear of sensitivity change due to mounting error and noise generation due to vibration. Moreover, the light from the light source 17 is applied to the lubricating oil through the optical fiber 15 on the light source side, and the light from the coloring agent added to the lubricating oil is irradiated on the optical fiber 15 on the light source side.
Since the light receiving portions 18A, 18B, ... Are configured to receive light via the light receiving portion side optical fibers 16A, 16B, which are parallel to the light receiving portion side optical fibers 16A, 16B ,.

As in the invention of claim 2, claim 1
In the lubricating oil state detection device in the refrigeration cycle described above, the light receiving unit side optical fibers 18A, 18B ...
In order to selectively observe the space Y ₁ , Y ₂ ··· where the visual field X ₀ from the light source side optical fiber 15 and the visual fields X ₁ , X ₂ ··· of the light receiving portion optical fibers 18A, 18B · · intersect. In the case of the configuration, information existing in the spaces Y ₁ , Y ₂ ··· where the visual field X ₀ from the light source side optical fiber 15 and the visual fields X ₁ , X ₂ ··· of the light receiving unit optical fibers 16A, 16B · · intersect. That is, the light intensity) can be detected, and the state change of the lubricating oil can be accurately detected.

As in the invention of claim 3, claim 1
In the lubricating oil state detection device in the refrigeration cycle according to any one of 1 and 2, the determination means 19 is provided while being provided in the bottom portion of the compressor 1 or in the suction pipe 8 between the evaporator 4 and the compressor 1. The light receiving portion 18A,
When the function of detecting the dilution degree of the lubricating oil from the change of the DC value component of the intensity signal of the light received by 18B ... Is provided, the light intensity signals of the light received by the light receiving portions 18A, 18B. Since the degree of dilution of the lubricating oil can be detected from the change in the DC value component, it is possible to predict the decrease in the viscosity of the lubricating oil.

As in the invention of claim 4, claim 1
3. The lubricating oil state detection device in the refrigeration cycle according to any one of 1 and 2 above, wherein the evaporator 4 and the compressor 1 are provided.
Is provided in the suction pipe 8 between
A, 18B ... Has two types of light receiving elements sensitive to the light from the colorant and other wavelength bands, and measures the oil amount and the mist-like liquid refrigerant amount by comparing the light intensities. In the case of a configuration having a function of, the amount of oil and the amount of mist-like liquid refrigerant can be measured respectively by comparing the light intensities received by the light receiving portions 18A, 18B, ... And the amount of liquid refrigerant can be known individually.

According to the invention of claim 5, in the lubricating oil state detecting device in the refrigerating cycle according to any one of claims 1, 2, 3 and 4, the light receiving section side optical fibers 16A, 16B ... When the optical path refraction member 32 for moving the detection area is provided at the tip of the, the field of view of the light-receiving side optical fibers 16A, 16B ... Can be freely adjusted, and the installation location can be freely selected.

According to a sixth aspect of the present invention, in the lubricating oil state detecting device in the refrigerating cycle according to any one of the first, second, third, fourth and fifth aspects, the lubricating oil state detecting device is provided at the bottom of the compressor 1. When the determination means 19 is configured to have a function of detecting foaming of the lubricating oil by selecting an arbitrary frequency component from the AC value component of the intensity signal of the light received by the light receiving portions 18A, 18B ... , Light receiving unit 18
A foaming of the lubricating oil can be detected by selecting an arbitrary frequency component from the AC value component of the intensity signal of the light received by A, 18B ..., It is possible to predict the insufficient supply of the lubricating oil to the compressor 1. .

According to the invention of claim 7, in the lubricating oil state detecting device in the refrigerating cycle according to any one of claims 1, 2, 3, 4, 5 and 6, a side surface of the compressor 1 is provided. The determination means 19 is provided at the oil level lower limit set height position P and the light receiving portion 18A,
When the function of detecting the oil level drop of the lubricating oil is detected from the presence or absence of the DC value component of the intensity signal of the light received by 18B ..., The intensity signal of the light received by the light receiving parts 18A, 18B. It is possible to detect a decrease in the oil level of the lubricating oil based on the presence or absence of the DC value component of, and it is possible to predict the insufficient supply of the lubricating oil to the compressor 1.

[Brief description of drawings]

FIG. 1 is a refrigerant circuit diagram showing a configuration of a general refrigeration cycle.

FIG. 2 is a cross-sectional view of essential parts of a compressor showing an example of use of a lubricating oil state detection device in a refrigeration cycle according to an embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view of the lubricating oil state detection device in the refrigeration cycle according to the embodiment of the present invention.

FIG. 4 is an enlarged plan view of the lubricating oil state detection device in the refrigeration cycle according to the embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a schematic configuration (that is, a signal processing system) of a determination unit in the lubricating oil state detection device in the refrigeration cycle according to the embodiment of the present invention.

FIG. 6 is an enlarged cross-sectional view of a suction pipe showing another usage example of the lubricating oil state detection device in the refrigeration cycle according to the embodiment of the present invention.

7 is a sectional view taken along line VII-VII in FIG.

8 is a sectional view taken along line VIII-VIII in FIG.

FIG. 9 is an enlarged cross-sectional view of a suction pipe showing another example of use of the lubricating oil state detection device in the refrigeration cycle according to the embodiment of the present invention.

10 is a sectional view taken along line XX of FIG.

11 is a sectional view taken along line XI-XI of FIG.

[Explanation of symbols]

1 is a compressor, 2 is a condenser, 3 is a decompression mechanism, 4 is an evaporator,
8 is a suction pipe, 10 is an oil sump, 14 is a fixing member, 1
Reference numeral 5 is a light source side optical fiber, 16A and 16B are light receiving portion side optical fibers, 17 is a light source, 18A and 18B are light receiving portions, 19 is determination means (circuit board), 32 is an optical path refraction member (prism), and A is state detection. Equipment, P is the oil level lower limit setting position,
X ₀ , X ₁ and X ₂ are visual fields, and Y ₁ and Y ₂ are spaces.

Claims (7)

[Claims] 1. A compressor (1), a condenser (2), a decompression mechanism (3), and an evaporator (4) are sequentially arranged in a refrigerant pipe (5).
A lubricating oil state detecting device for a refrigerating cycle, which is provided in an appropriate place of the refrigerating cycle connected by (8), and comprises a plurality of optical fibers (15) installed in parallel in a fixing member (14) having an airtight pressure-proof structure. ), (16A), (16
B) ... and the optical fibers (15), (16A), (1
8B) ... A light source (17) and a light receiving section (1
8A), (18B) ... And the light receiving parts (18A), (1
8B) .. Determination means (19) for judging the state of the lubricating oil from the received light, and irradiating the lubricating oil with the light from the light source (17) through the optical fiber (15), Light from an oil-soluble colorant added to the lubricating oil is received by the light receiving portions (18A), (18B), ... through the optical fibers (16A), (16B) ,. A lubricating oil state detection device in a refrigeration cycle, characterized in that 2. The light receiving section side optical fiber (16A),
(16B) ... is the field of view (X ₀ ) from the light source side optical fiber (15) and the light receiving section side optical fibers (16A), (1
6B) ··· The field of view (X ₁ ), (X ₂ ) · · · intersecting space (Y ₁ ), (Y ₂ ) · · · is configured to selectively observe Item 2. A lubricating oil state detection device in the refrigeration cycle according to Item 1. 3. The determination means (19) is provided at the bottom of the compressor (1) or in the suction pipe (8) between the evaporator (4) and the compressor (1). 3. The light receiving sections (18A), (18B) ... Having a function of detecting the degree of dilution of the lubricating oil from the change in the direct current value component of the intensity signal of the light received. 13. A lubricant oil state detection device in the refrigeration cycle according to any one of claims 1 to 4. 4. The light receiving section (18) is provided in a suction pipe (8) between the evaporator (4) and the compressor (1).
A), (18B) ... have two types of light receiving elements having sensitivity to the light from the colorant and other wavelength bands, and comparing the light intensities with the oil amount and the mist-like liquid refrigerant amount. The lubricating oil state detection device in the refrigeration cycle according to any one of claims 1 and 2, wherein the device is provided with a function of measuring each of the above. 5. The optical fiber (16A) on the light receiving section side,
The refrigeration cycle according to any one of claims 1, 2, 3 and 4, wherein an optical path refracting member (32) for moving the detection area is provided at the tip of (16B). Lubricating oil condition detection device. 6. The determination means (19) is provided at the bottom of the compressor (1), and the determination means (19) includes the light receiving section (18A),
(18B) ···· The function for detecting foaming of lubricating oil by selecting an arbitrary frequency component from the AC value component of the intensity signal of the received light,
The lubricating oil state detection device in the refrigeration cycle according to any one of 2, 3, 4 and 5. 7. The determination means (1) is provided at an oil level lower limit set height position (P) of the compressor (1).
9) is characterized in that it has a function of detecting a decrease in the oil level of the lubricating oil from the presence or absence of a DC value component of the intensity signal of the light received by the light receiving portions (18A), (18B). The lubricating oil state detection device in the refrigeration cycle according to any one of claims 1, 2, 3, 4, 5 and 6.