JP2003156271A - Liquid-level detection device, liquid reservoir, refrigerating cycle device, refrigerant leakage detection system and liquid-level detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid-level detection device capable of after-setting itself against an existing liquid reservoir without applying work for setting to the liquid reservoir, detecting refrigerant leakage of a refrigerating cycle at an early stage, high in convertibility even against a different kind of a refrigerant, capable of certainly detecting refrigerant quantity of the liquid reservoir and high in an installing property and in reliability, the liquid reservoir, a refrigerating cycle device, a refrigerant leakage detection system and a liquid-level detection method. SOLUTION: This liquid-level detection device 15 to detect a liquid-level position of the refrigerant reserved in the liquid reservoir 4 set in the refrigerating cycle is furnished with a transmission part to transmit a propagating wave to inject in the liquid-level of the refrigerant after permeating a peripheral wall of the liquid reservoir 4 from the outside of the liquid reservoir 4 and a receiving part to receive the propagating wave to outgo to the outside of the liquid reservoir 4 by permeating the peripheral wall after reflecting on or permeating the liquid-level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid level detection device installed in a liquid reservoir of a refrigeration cycle apparatus, a liquid reservoir, a refrigeration cycle device, a refrigerant leak detection system, and a liquid level detection method, and more particularly to a refrigeration cycle. The present invention relates to a liquid level detection device for detecting the presence / absence of leakage of a refrigerant from a device, a liquid reservoir, a refrigeration cycle device, a refrigerant leakage detection system, and a liquid level detection method.

[0002]

2. Description of the Related Art Conventionally, in refrigeration cycle devices,
For the purpose of always circulating an appropriate amount of refrigerant in the refrigeration cycle regardless of the state of the refrigeration cycle, a liquid reservoir for storing excess refrigerant in the refrigeration cycle is installed. Further, in a refrigeration cycle apparatus having a liquid reservoir installed, a technique for detecting the presence or absence of leakage of a refrigerant from the apparatus is disclosed.

The refrigerant filled in the refrigeration cycle device will be briefly described below. Take refrigeration cycle equipment installed in supermarkets as an example. The number of showcases installed in the food section of the store, etc.
The size, type, and layout will differ from store to store. Therefore, the internal volume of the evaporator arranged in the showcase also differs. Further, the installation locations of the compressor, the condenser, and the liquid reservoir in the refrigeration cycle apparatus also differ depending on the structure of the store. For example, a compressor or the like may be installed behind the food counter or may be installed on the rooftop. In this way, the distance between the compressor, the condenser, and the liquid reservoir with respect to the evaporator is different for each store, and the length of the low pressure gas pipes and high pressure liquid pipes for connecting them is also different. Become.

On the other hand, in order for the refrigeration cycle to exhibit a predetermined performance, it is necessary to have an amount of refrigerant suitable for the internal volume of the refrigeration cycle. Therefore, as described above, if the internal volume of the evaporator and the length of the pipe are different, the amount of refrigerant required for the entire refrigeration cycle also becomes different. Since the amount of refrigerant to be filled in the refrigeration cycle device differs depending on the store, the device is filled with the refrigerant after the refrigeration cycle device is installed in the shop.

Furthermore, the required amount of refrigerant in the refrigeration cycle apparatus also differs depending on the state of the refrigeration cycle. That is, the state of the refrigeration cycle varies depending on the outside air temperature and the operating state of load side equipment such as a showcase, and the amount of refrigerant required for the refrigeration cycle varies depending on the state. Therefore, the device is filled with an amount of refrigerant suitable for the worst state so that the required amount of refrigerant is constantly supplied to each component such as the condenser and the evaporator regardless of the state of the refrigeration cycle. The amount of refrigerant distributed to the compressor, the condenser, the evaporator, and the pipes is determined by their respective internal volumes, performances, and operating conditions. Then, among the refrigerants filled in the refrigeration cycle, surplus refrigerants other than the circulating refrigerant supplied to the respective components of the refrigeration cycle are stored in the liquid reservoir.

Hereinafter, referring to FIG. 10, for example, Japanese Patent Laid-Open No. 10-
A conventional refrigeration cycle device disclosed in Japanese Patent No. 103820 will be briefly described. FIG. 10 is a refrigeration cycle apparatus having a liquid reservoir installed therein, and relates to a technique for detecting the presence or absence of leakage of a refrigerant from the apparatus. In the figure, 101 is a compressor, 102 is a condenser, 103 is a liquid reservoir,
104 is a pressure reducing device (expansion valve), 105 is an evaporator, 106
Is a high pressure gas pipe, 107 is a high pressure liquid pipe, 108 is a solenoid valve, 1
Reference numeral 09 is a low-pressure liquid pipe, 110 is a low-pressure gas pipe, 111 is a low-pressure pressure switch, 112 is an auxiliary tank, 112a is a lower communication pipe, 112b is an upper communication pipe, and 113 is a float type level sensor.

Here, the compressor 101, the condenser 102, the liquid reservoir 103, the pressure reducing device 104, and the evaporator 105 are sequentially connected to form a refrigerant cycle. And the reservoir 1
03 and the auxiliary tank 112, the communication pipe 112a, 112
It communicates by b. As a result, the liquid refrigerant in the liquid reservoir 103 and the liquid refrigerant in the auxiliary tank 112 maintain the same liquid level. The auxiliary tank 11
2, a float type level sensor 113 is arranged to detect the liquid level of the refrigerant in the auxiliary tank 112. Then, by comparing the liquid level detected by the float type level sensor 113 with a predetermined normal liquid level, the presence or absence of refrigerant leakage from the refrigeration cycle device is detected.

Hereinafter, referring to FIG. 11, for example, Japanese Unexamined Patent Publication No. 6-1
Another conventional refrigeration cycle device disclosed in Japanese Patent No. 85839 will be briefly described. FIG. 11 also corresponds to FIG.
Similarly to the above, a refrigeration cycle apparatus having a liquid reservoir installed,
The present invention relates to a technique for detecting the presence / absence of leakage of a refrigerant from a device. In the figure, 202 is a compressor, 203 is a condenser, 204 is a liquid reservoir (receiver tank), 205 is a pressure reducing device (control valve), 206 is a showcase, 207 is an evaporator, 208 is a liquid take-out pipe, and 209 is Flow site (site glass), 210 is a dryer, 211 is an accumulator, 212 is a light emitter, 213 is a light receiver, and 214 is a discrimination circuit.

Here, the compressor 202, the condenser 203, the liquid reservoir 204, the pressure reducing device 205, and the evaporator 207 are sequentially connected to form a refrigerant cycle. And the liquid reservoir 2
A flow site 209 is installed via a dryer 210 in a liquid take-out pipe 208 whose one end is connected to the bottom surface of 04. The flow site 209 confirms the state of the liquid refrigerant flowing out from the liquid reservoir 204. Specifically, the light emitter 2 is directed toward the liquid refrigerant flowing in the flow site 209.
After the light is projected from 12, the returned light is received by the light receiver 213. After that, the detection signal of the light receiver 213 is transmitted to the determination circuit 214, and the determination circuit 214 detects the presence or absence of mixing of bubbles in the liquid refrigerant, that is, the presence or absence of refrigerant leakage, according to the level of the signal.

[0010]

The above-mentioned conventional refrigeration cycle apparatus has the following problems. First, the refrigeration cycle apparatus described with reference to FIG. 10 detects the liquid surface position in the liquid reservoir at the liquid surface position in the auxiliary tank and tries to detect the refrigerant leakage based on the detection result. is there. Therefore, the liquid reservoir and the auxiliary tank must be provided with through holes in their peripheral walls for installing the communication pipes. In addition, the auxiliary tank also requires processing to install a float type level sensor. As described above, the installation of the liquid surface detection device for detecting the liquid surface position in the liquid reservoir is relatively laborious. Further, it is difficult to install the liquid level detection device afterwards on the existing refrigeration cycle device because of the necessity of processing the above-described through holes and the like. In particular,
Many of the existing refrigeration cycle devices are operating with almost no rest, which makes it difficult to retrofit the liquid level detection device.

Next, in the refrigeration cycle apparatus described with reference to FIG. 11, a flow site is installed on the downstream side of the liquid pool in the refrigeration cycle to detect the presence or absence of bubbles in the liquid refrigerant passing through the flow site, It is intended to detect refrigerant leakage. Here, the state in which bubbles are contained in the liquid refrigerant occurs when the liquid refrigerant in the liquid reservoir is almost exhausted and the liquid level of the refrigerant drops to the position of the bottom surface of the liquid reservoir. Therefore, the refrigerant leakage in the refrigeration cycle cannot be detected early, and when the refrigerant leakage is detected, the performance of the refrigeration cycle may be deteriorated due to insufficient refrigerant. That is, according to the above-mentioned supermarket example, there is a problem in that it is impossible to refill the refrigerator with the refrigerant before the food in the showcase is heated and deteriorates in freshness.

Further, as a common problem with the refrigeration cycle apparatus of FIGS. 10 and 11, when replacing an existing refrigerant circulating in the apparatus with a refrigerant of a different type, compatibility of the refrigerant leakage detection apparatus is a problem. There was a problem of being low. Specifically, the R22 refrigerant that has been widely used in the past is HCFC.
Since it is a system refrigerant, in consideration of the environment such as global warming, the shift to alternative refrigerants is being promoted within a global framework. Therefore, when it is necessary to replace the refrigerant in the existing refrigeration cycle apparatus that uses the R22 refrigerant, it is necessary to replace it with the alternative refrigerant. Here, since the alternative refrigerant has a considerable chemical property different from that of the R22 refrigerant, the alternative refrigerant cannot be directly replaced in the existing refrigeration cycle. That is, with respect to the existing refrigeration cycle apparatus, various conditions must be changed so as to be compatible with the alternative refrigerant, and a cycle equivalent to the conventional refrigeration cycle must be achieved. Similarly, regarding the refrigerant leakage detection device, it is necessary to change various conditions so that the existing detection device is adapted to the alternative refrigerant. In the device of FIG. 10, for example, it becomes necessary to change the conditions of the communication pipe, the detection conditions of the float type level sensor, and the like. Further, in the device of FIG. 11, it is necessary to change the conditions of the light emitter and the light receiver, for example.

On the other hand, if the liquid surface position of the liquid refrigerant in the liquid reservoir can be directly detected, the above problem can be solved. Details are as described below.
The amount of refrigerant in the liquid reservoir, that is, the position of the liquid surface in the liquid reservoir, changes from moment to moment depending on the state of the refrigeration cycle. However, the amount of refrigerant in each component can be calculated by measuring the pressure and saturation temperature of the refrigerant in each component such as the condenser and the evaporator. That is, if the temperature and pressure of the refrigerant are known, the amount of the refrigerant can be calculated from the equation of state and the density of the refrigerant. Here, since the calculated refrigerant amount is the amount of the refrigerant actually circulating in the refrigerant cycle, by subtracting this refrigerant amount from the refrigerant filling amount actually filled in the device, The theoretical amount of refrigerant can be estimated. Therefore, it is possible to detect the presence or absence of refrigerant leakage from the refrigeration cycle by comparing this theoretical amount of liquid refrigerant with the actual detected amount of liquid refrigerant in the liquid reservoir. For example, by comparing the amount of the liquid pool refrigerant measured at a predetermined time with the theoretical amount of the liquid pool refrigerant in the operating state of the normal refrigeration cycle or the theoretical amount of the liquid pool refrigerant at the predetermined time, the amount of the liquid pool refrigerant It will be calculated and judged whether the change of is within the normal change range. Then, when the change in the amount of the pooled refrigerant is outside the normal change range, it can be considered that the refrigerant has leaked from the refrigeration cycle device.

However, the liquid reservoir stores the high-pressure liquid refrigerant therein. Therefore, the liquid reservoir needs to be formed of a metal such as a carbon steel pipe for pressure piping to form a pressure vessel in which the pressure resistance strength in accordance with the regulations is secured. Therefore, even if a transparent peep window can be provided on a part of the peripheral wall of the liquid reservoir, it is difficult to form most of the peripheral wall with a transparent member such as glass. A practical liquid reservoir is an opaque container in which most of the peripheral wall is made of metal such as carbon steel pipe for pressure piping. Here, opaque means optically opaque. Therefore, it is difficult to optically measure the liquid surface in the liquid reservoir or to visually see through the entire liquid reservoir in the liquid reservoir in which most of the peripheral wall is made of an opaque member. As described above, it is possible to provide a viewing window in a part of the peripheral wall of the liquid reservoir, but even in that case, the liquid surface position in the liquid reservoir is constantly changing, so that liquid It is difficult to accurately measure and monitor the surface position from the viewing window.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to retrofit an existing liquid pool without performing a process for installing the liquid pool, and a refrigeration cycle. Can detect the leakage of refrigerant at an early stage and is highly compatible with different kinds of refrigerants, and can reliably detect the amount of refrigerant in the liquid pool. The installation level and reliability of the liquid level detector, liquid pool, and refrigeration cycle are high. An object of the present invention is to provide an apparatus, a refrigerant leakage detection system, and a liquid level detection method.

[0016]

The inventor of the present application has come to know the following matters as a result of repeated research for solving the above problems. That is, an ultrasonic wave (defined as a high-frequency vibration sound wave having a straight traveling property) has a property of propagating in any medium such as gas, liquid or solid. Therefore, by utilizing this property, the liquid level of the refrigerant in the liquid reservoir can be measured from the outside of the liquid reservoir via the peripheral wall.

The details will be described below. An ultrasonic wave is a propagating wave that travels linearly in any medium, that is, any medium of gas, liquid, and solid. The velocity (propagation velocity or speed of sound) of ultrasonic waves propagating in a medium is
It depends on the type of medium and temperature. FIG. 12 shows the speed of sound with respect to temperature in a typical medium. In the figure, R22, R404A, and R407C are freon-based refrigerants, and the respective sound velocities in the gas state and the liquid state are described. In addition, R404A, R407C
Is a mixed refrigerant in which a plurality of kinds of refrigerants are mixed, and is an HFC-based refrigerant (alternative refrigerant) in consideration of the environment. In the figure, a standard composition ratio is shown. Specifically, the standard composition ratio for R404A is R3
2, R125, R134A = 44 wt%, 4 wt%, 5
2 wt%, and the standard composition ratio in R407C is R125, R134A, R143A = 23 wt%,
25 wt% and 52 wt%.

As described above, the ultrasonic wave travels in a predetermined medium at a predetermined sound velocity. Then, when the ultrasonic waves reach the boundary between different media, a part of the ultrasonic waves is reflected by the boundary surface and the other is transmitted through the boundary surface. Where the ultrasound is
When the medium 1 having the density ρ ₁ and the propagation velocity c ₁ is perpendicularly incident on the medium 2 having the density ρ ₂ and the propagation velocity c ₂ , the reflectance R and the transmittance of the ultrasonic wave at the interface between the medium 1 and the medium 2 T is expressed by the following equation. R = (ρ ₂ × c ₂ −ρ ₁ × c ₁ ) / (ρ ₁ × c ₁ + ρ ₂
× c ₂ ) T = 1-R

Further, the time τ during which the ultrasonic wave propagates in a predetermined medium is obtained from the following equation from the propagation velocity c and the propagation distance L in the medium. τ = L / c Therefore, a transmitter that transmits ultrasonic waves toward the medium,
A thickness of the medium can be determined by the following equation by installing a receiver for receiving the ultrasonic wave reflected and returned by the boundary surface of the medium and measuring the time Δt from the transmission to the reception by the following equation. L = (Δt × c) / 2

Regarding the above-mentioned properties of ultrasonic waves,
Reference was made to "Fundamentals and Applications of High Frequency" (October 20, 1990, published by Tokyo Denki University Press). Also air,
As for the speed of sound of water and metal, the data of "Science chronology" (November 30, 1995, published by Maruzen) was used. further,
Regarding the sound velocity of freon, based on the data of the above-mentioned "Science chronology", "REFPROP Ver 6.01" (19
It was calculated using software released in 1998 by NIST).

The present invention has been made in order to solve the above-mentioned problems based on the above-mentioned research results, that is, the liquid level detection device according to the first aspect of the present invention is installed in a refrigeration cycle. A liquid level detecting device for detecting the liquid level position of the refrigerant stored in the liquid pool, which emits a propagating wave incident on the liquid level of the refrigerant after passing through the peripheral wall of the liquid pool from the outside of the liquid pool. The transmitter includes a transmitter, and a receiver that receives the propagating wave that is reflected or transmitted by the liquid surface and then passes through the peripheral wall and is emitted to the outside of the liquid reservoir.

The liquid level detection device according to a second aspect of the present invention is the liquid level detection device according to the first aspect, wherein the liquid level detection device is detachably installed on the peripheral wall of the liquid reservoir.

Further, the liquid level detecting device according to a third aspect of the present invention is the liquid level detecting device according to the first or second aspect of the invention, wherein the refrigerant from the refrigeration cycle is based on the detected value of the liquid level position. It is intended to detect the leakage of.

Further, in the liquid level detecting device according to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the propagating wave is an ultrasonic wave, and the ultrasonic wave is an ultrasonic wave. The controller includes a controller that obtains the liquid surface position based on the time from when the transmitter is emitted to when the receiver is reached.

According to a fifth aspect of the present invention, in the liquid level detection device according to the fourth aspect, the controller causes a detection error of the liquid level position due to the rocking of the refrigerant in the liquid reservoir. It is formed so that it can be corrected.

Further, the liquid level detection device according to a sixth aspect of the present invention is the liquid level detection device according to the fourth or fifth aspect of the invention, wherein the temperature of the refrigerant in the liquid reservoir and / or the temperature of the peripheral wall is detected. Further comprising a temperature detector, wherein the controller comprises a storage device that holds data of the propagation velocity of the ultrasonic wave depending on the temperature of the refrigerant or / and the temperature of the peripheral wall, and the detected value detected by the temperature detector. And the liquid level position of the refrigerant based on the data of the storage device corresponding to the detected value.

According to a seventh aspect of the present invention, in the liquid level detection device according to any one of the fourth to sixth aspects, the refrigerant is an R22 refrigerant in which a change in propagation velocity with respect to a temperature change. Is smaller than.

Further, the liquid level detecting device according to an eighth aspect of the present invention is the liquid level detecting device according to any one of the fourth to seventh aspects, wherein the refrigerant is a mixture composed of a plurality of types of refrigerants. The refrigerant is composed so that the fluctuation of the liquid surface position due to the fluctuation of the composition ratio of the refrigerant due to the temperature change is within the range of the detection accuracy of the liquid surface position.

A liquid level detecting device according to a ninth aspect of the present invention is the liquid level detecting device according to any of the first to third aspects, wherein the propagating wave is a light wave and the peripheral wall is the light wave. It is provided with a transparent portion through which a light wave can pass.

A liquid reservoir according to a tenth aspect of the present invention is provided with the liquid level detection device according to any one of the first to ninth aspects.

A refrigeration cycle apparatus according to an eleventh aspect of the present invention includes the liquid reservoir according to the tenth aspect.

According to a twelfth aspect of the present invention, there is provided a refrigerant leakage detection system in which the data of the liquid level detection device in the refrigeration cycle apparatus according to the eleventh aspect is
It is provided with a remote monitoring unit that obtains via a communication line.

Further, in the refrigerant leakage detection system according to the invention described in claim 13, in the invention described in claim 12, the remote monitoring unit includes the liquid level detected by the liquid level detection device via the communication line. The position is detected.

Further, in the refrigerant leakage detection system according to the invention described in claim 14, in the invention described in claim 12 or 13, the refrigeration cycle device is a plurality of networked refrigeration cycle devices. It is a thing.

A refrigerant leakage detection system according to a fifteenth aspect of the present invention is based on the liquid level position detected by the liquid level detection device in the invention according to any one of the twelfth to fourteenth aspects. A refrigerant leakage detection device for detecting leakage of refrigerant from the refrigeration cycle is provided, and the data of the liquid level detection device is transmitted to the remote monitoring unit via the refrigerant leakage detection device.

A liquid level detecting method according to a sixteenth aspect of the present invention is a liquid level detecting method for detecting a liquid level position of a refrigerant stored in a liquid reservoir installed in a refrigeration cycle. A step of transmitting ultrasonic waves from the outside of the liquid reservoir toward the liquid surface of the refrigerant; a step of receiving the ultrasonic waves reflected or transmitted by the liquid surface outside the liquid reservoir; Is detected and the liquid level position of the refrigerant is detected based on the time from the transmission to the reception.

Further, in the liquid level detecting method according to the seventeenth aspect of the present invention, in the invention of the above sixteenth aspect, the step of detecting the liquid level position is performed by a liquid due to the fluctuation of the refrigerant in the liquid reservoir. This includes the step of correcting the detection error of the surface position.

The liquid level detecting method according to the eighteenth aspect of the present invention further comprises the step of detecting the temperature of the refrigerant and / or the peripheral wall in the invention of the sixteenth aspect or the seventeenth aspect, The step of detecting the liquid surface position includes a step of obtaining the propagation velocity of the ultrasonic wave based on the detection value detected by the step of detecting the temperature.

Further, the liquid level detecting method according to the invention of claim 19 is the method according to any one of claims 16 to 18, wherein the liquid level detected by the step of detecting the liquid level position. The method further comprises the step of detecting leakage of the refrigerant from the refrigeration cycle based on the position.

According to a twentieth aspect of the present invention, in the liquid level detection method according to the nineteenth aspect of the present invention, the step of detecting the leakage of the refrigerant is performed based on the amount of the filled refrigerant filled in the refrigeration system. A theoretical liquid pool refrigerant amount minus the amount of circulating refrigerant circulating through the refrigeration cycle, and the actual liquid pool refrigerant amount obtained based on the liquid surface position detected by the step of detecting the liquid surface position, This is a step for comparison.

[0041]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will now be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and the duplicate description thereof will be appropriately simplified or omitted.

Embodiment 1. The first embodiment of the present invention will be described in detail with reference to FIGS. 1 is a configuration diagram showing a refrigeration cycle apparatus according to Embodiment 1 of the present invention. In FIG. 1, 1 is a compressor, 2 is a condenser,
3 is a condenser blower, 4 is a liquid reservoir, 5 is an electromagnetic valve, 6 is a pressure reducing device (expansion means), 7 is an evaporator, 8 is an evaporator blower,
9 is a high pressure gas pipe, 10 is a low pressure gas pipe, 11 is a liquid reservoir 4
High pressure liquid pipe on the inlet side, 12 is a high pressure liquid pipe on the outlet side of the liquid reservoir 4, 13 is a refrigerant leakage detection device (refrigerant leakage detection means),
Reference numeral 15 represents a liquid level detecting device (liquid level measuring means).

Here, the compressor 1, the solenoid valve 5, the pressure reducing device 6, the evaporator 7, and the evaporator blower 8 are respectively installed in a single number or a plurality of numbers. Further, the condenser 2 and the condenser blower 3 are installed in a machine room or outdoors. On the other hand, the evaporator 7 and the blower 8 for the evaporator are built in, for example, a showcase in the room. The liquid level detection device 15 is detachably installed on the peripheral wall of the liquid reservoir 4 and detects the liquid surface position of the refrigerant in the liquid reservoir 4 as described later.
Further, the refrigerant leakage detection device 13 is electrically connected to the liquid level detection device 15, and, as described later, based on the data of the liquid level position detected by the liquid level detection device 15, the refrigerant from the refrigerant cycle. Detect leaks.

The operation of the refrigerant in the refrigerating cycle of the refrigerating cycle device configured as described above will be described. First, the low-temperature low-pressure gas refrigerant is compressed by the compressor 1 to become a high-temperature high-pressure gas refrigerant. The high-temperature and high-pressure gas refrigerant flowing out from the compressor 1 is passed through the high-pressure gas pipe 9 to the condenser 2
Flow into. The gas refrigerant flowing into the condenser 2 is
It exchanges heat with the surrounding fluid such as air or water to radiate heat and become a high temperature and high pressure liquid refrigerant. The high-temperature high-pressure liquid refrigerant flowing out of the condenser 2 flows into the liquid reservoir 4 via the high-pressure liquid pipe 11 connected to the liquid reservoir inlet at the upper part of the liquid reservoir 4. The high-temperature and high-pressure liquid refrigerant that has flowed into the liquid reservoir 4 passes through the solenoid valve 5 via the high-pressure liquid pipe 12 connected to the liquid reservoir outlet at the bottom of the liquid reservoir 4, and then flows into the decompression device 6. The liquid refrigerant flowing into the decompression device 6 is decompressed here and becomes a low temperature and low pressure gas-liquid two-phase refrigerant. The gas-liquid two-phase refrigerant flowing out of the decompression device 6 flows into the evaporator 7. The gas-liquid two-phase refrigerant that has flowed into the evaporator 7 exchanges heat with the fluid around the evaporator 7, for example, air, and becomes a low-temperature low-pressure gas refrigerant. Due to the heat exchange at this time, the surroundings of the evaporator 7 are deprived of heat and frozen. After that, the low-temperature low-pressure gas refrigerant flowing out of the evaporator 7 returns to the compressor 1 via the low-pressure gas pipe 10.

FIG. 2 is a Mollier diagram (PH diagram) showing the operation of the refrigerant in the refrigeration cycle apparatus of FIG.
In the figure, the horizontal axis represents the enthalpy of the refrigerant, and the vertical axis represents the pressure of the refrigerant. Further, the reference numerals in the diagram correspond to the reference numerals in FIG. 1, and show the functions of the respective constituent devices constituting the refrigeration cycle for changing the state of the refrigerant. As shown in the figure, in the refrigeration cycle apparatus, a refrigeration cycle consisting of adiabatic compression, isobaric cooling, isenthalpic expansion, and isothermal isobaric expansion is repeated.

Next, referring to FIGS. 3 and 4, the liquid level detection device 15
The configuration and operation of will be described in detail. FIG. 3 is a schematic diagram showing the liquid reservoir 4 in the refrigeration cycle apparatus of FIG. In FIG. 3, 14 is a peripheral wall (housing) of the liquid reservoir 4 made of carbon steel pipe for pressure piping, 15 is a liquid level detecting device, 15a is an ultrasonic sensor of the liquid level detecting device 15, and 15b is a liquid level detecting device. A controller 15 and a liquid level 16 are shown.

In FIG. 3, the ultrasonic sensor 15a
Are closely attached to the peripheral wall 14 without air. Specifically, a mounting member made of a soft material is provided between the ultrasonic sensor 15a and the peripheral wall 14, and
Pressure is applied to the ultrasonic sensor 15a to bring it into close contact with the peripheral wall 14. Thereby, air does not enter between the ultrasonic sensor 15a and the peripheral wall 14, so that the detection accuracy of the ultrasonic sensor 15a is improved. The mounting member is, for example,
It is made of rubber or gel material. The ultrasonic sensor 15a is pressurized by, for example, a method using the magnetic force of a magnet or a method using the tension of the belt.

FIG. 4 is a schematic view showing the liquid level detection device 15 in the liquid reservoir 4 of FIG. In FIG. 4, 23 is a transmitter (transmitter) of the ultrasonic sensor 15a, 24 is a receiver (receiver) of the ultrasonic sensor 15a, and 25 is a controller 15.
b is an ultrasonic wave generation circuit, 26 is a storage device such as a memory of the controller 15b, 27 is a timer of the controller 15b, 28 is an arithmetic device of the controller 15b, 29 is an output device such as a liquid crystal display of the controller 15b, a D / A converter. , 30 are temperature detectors for detecting the temperature of the refrigerant in the liquid reservoir and the temperature of the peripheral wall. In addition, the transmission unit 23,
The ultrasonic waves emitted from the ultrasonic wave are installed so as to enter the liquid surface 16 of the refrigerant substantially vertically.

Here, the transmitter 23 of the ultrasonic sensor 15a shown in FIG. 4 can be formed of, for example, a magnetostrictive vibrator, an electrostrictive vibrator, a piezoelectric vibrator, or the like. Details are as follows. The magnetostrictive oscillator is made of a metal such as nickel or an iron-aluminum alloy, or a nickel-copper-cobalt ferrite, and expands or contracts when a magnetic field is applied to it. Utilizing this property, a high-frequency current is passed through the winding to form a magnetic field and ultrasonic vibration is generated. Further, the electrostrictive oscillator is a barium titanate porcelain, a lead zirconate titanate porcelain porcelain, etc., to which a silver electrode is applied, and it expands and deforms when a direct current electric field is formed on the silver electrode. Utilizing this property, a high-frequency electric field is formed between the electrodes to generate ultrasonic vibration. Further, the piezoelectric vibrator is made of a piezoelectric crystal such as crystal, Rochelle salt, or piezoelectric ceramic, and expands or contracts or slips when an electric field is formed on it. Utilizing this property, a high frequency voltage is applied to the piezoelectric crystal to generate ultrasonic vibration.

Here, as shown in FIG. 3, the ultrasonic sensor 15a in which the transmitter and the receiver are integrated is installed at the bottom of the peripheral wall 14 in the liquid reservoir 4. Then, the ultrasonic wave transmitted from the transmitting portion of the ultrasonic sensor 15 a enters from the outside of the peripheral wall 14 of the liquid reservoir 4. The ultrasonic waves incident on the peripheral wall 14 are propagated inside the peripheral wall 14 at a propagation velocity according to the material,
The boundary surface between the peripheral wall 14 and the liquid refrigerant is reached. Part of the ultrasonic waves that have reached the boundary surface between the peripheral wall 14 and the liquid refrigerant is reflected by the boundary surface, and then propagates through the peripheral wall 14 again, and the ultrasonic sensor 1
It is received by the receiving unit 5a. On the other hand, the rest of the ultrasonic waves reaching the boundary surface between the peripheral wall 14 and the liquid refrigerant penetrate the boundary surface. The reflectance and transmittance of ultrasonic waves at this time are
It can be calculated by the formula described above.

On the other hand, the ultrasonic waves that have passed through the boundary surface between the peripheral wall 14 and the refrigerant liquid are propagated in the liquid refrigerant at a propagation speed according to the physical properties and temperature of the liquid refrigerant, and are the boundary surface between the liquid refrigerant and the gas refrigerant. It reaches the liquid surface 16. Then, a part of the ultrasonic waves that have entered the liquid surface 16 is reflected by the liquid surface 16, then propagates again in the liquid refrigerant, further passes through the peripheral wall 14, and is received by the receiving portion of the ultrasonic sensor 15a. It It should be noted that some of the ultrasonic waves that have passed through the liquid refrigerant after being reflected at the boundary surface 16 between the liquid refrigerant and the gas refrigerant are reflected at the boundary surface between the liquid refrigerant liquid and the peripheral wall 14 when entering the peripheral wall 14. Then, after that, the reflection may be repeatedly reflected on another boundary surface to reach the receiving unit. Also,
In some cases, the ultrasonic wave that has passed through the liquid surface 16 is reflected by the upper portion of the peripheral wall 14 and then passes through the gas refrigerant, the liquid refrigerant, and the peripheral wall 14 to reach the receiving portion. In this way, the ultrasonic waves emitted from the transmitting unit reach the receiving unit by following various routes. However, the ultrasonic waves that reach the receiving unit are, for example,
By measuring the time from the transmission to the reception, it is possible to discriminate which route the ultrasonic wave has passed through by calculation.

Next, the operation of the liquid level detecting device 15 will be described with reference to FIG. First, the transmitter 23 is operated by the ultrasonic wave generation circuit 25 of the controller 15b. As a result, ultrasonic waves are generated from the transmitter 23. Then, the ultrasonic waves emitted from the transmitting unit 23 are received by the receiving unit 24 after being reflected by the liquid surface of the refrigerant, as described above. Then, the reception signal of the reception unit 24 is sent to the arithmetic unit 28. On the other hand, the storage device 26 holds data on the propagation velocity of ultrasonic waves due to the temperature of the peripheral wall 14 and data on the thickness of the peripheral wall 14. Further, the storage device 26 also holds data such as ultrasonic wave propagation speed depending on the temperatures of the liquid refrigerant and the gas refrigerant. Then, these data are calculated by the arithmetic unit 2
8 is transmitted.

The timer 27 also holds time-related data, and these data are also transmitted to the arithmetic unit 28. Further, the temperature detector 30 detects the temperature of the refrigerant in the liquid reservoir 4 and the temperature of the peripheral wall 14 and holds these data. Then, those data are also stored in the arithmetic unit 2
8 is transmitted.

Then, in the arithmetic unit 28, based on the transmitted various data, the ultrasonic waves reflected and returned at the boundary surface between the peripheral wall 14 and the liquid refrigerant and the boundary surface between the liquid refrigerant and the gas refrigerant are returned. The ultrasonic waves that have returned after being reflected and the ultrasonic waves that have returned via other various paths are separated by calculation.
Then, the position of the liquid surface 16 in the liquid reservoir 4 is detected based on the time from the transmission to the reception in the ultrasonic waves reflected and returned at the boundary surface between the liquid refrigerant and the gas refrigerant. Further, the data of the liquid surface position calculated by the calculation device 28 is transmitted to the output device 29, and the data is output to the output device 29.

As described above, according to the first embodiment, the liquid level detecting device capable of detecting the position of the liquid level 16 in the liquid reservoir 4 without performing any special processing on the peripheral wall 14 of the liquid reservoir 4. 15
Can be detachably installed on the peripheral wall 14. Then, based on the detection result of the liquid level detection device 15, the actual amount of refrigerant in the liquid reservoir 4 is obtained, and the amount of refrigerant leakage from the refrigeration cycle is calculated by subtracting it from the theoretical amount of liquid refrigerant stored. You can ask. Note that these calculations are performed by the refrigerant leakage detection device 13 to which the detection data of the liquid level detection device 15 is transmitted, with reference to FIG.

Next, a method for improving the detection accuracy of the liquid surface 16 by the liquid surface detecting device 15 in the first embodiment will be described. When the refrigeration cycle apparatus is operating, the liquid level in the liquid reservoir 4 is hardly stationary, and the liquid level in the liquid reservoir 4 is oscillating. this is,
This is because the refrigerant constantly flows into and out of the liquid reservoir 4 in the refrigeration cycle. Specifically, when the refrigeration cycle apparatus is operating, the liquid level position of the refrigerant in the liquid reservoir 4 moves up and down with a width of several mm.

The mechanism of swinging of the liquid surface 16 in the liquid reservoir 4 will be described below. Referring to FIG. 3, a high-pressure liquid pipe 11 on the liquid reservoir inlet side is installed above the liquid reservoir 4. The liquid refrigerant flowing from the high-pressure pipe 11 falls downward as it is and collides with the refrigerant liquid surface 16 due to gravity and inertial force. The collision energy at that time causes the liquid refrigerant liquid surface 16 to swing. The collision energy due to the collision between the liquid refrigerant and the liquid surface 16 varies depending on the distance between the high pressure liquid pipe 11 and the liquid surface 16 (the height of the liquid surface 16) and the amount of refrigerant circulation circulating in the refrigeration cycle.
If the collision energy is different, the swing width of the refrigerant liquid surface 16 is also different. According to an experiment conducted by the inventor of the present application, the swing width of the liquid surface 16 is approximately ± 1 mm to ± 4 m.
m, and the oscillation frequency is approximately 1 Hz to 3 H
z.

Further, since a swirl flow is generated in the liquid refrigerant in the liquid reservoir 4, the liquid surface 16 of the refrigerant is also swung by this. This vortex flow is regarded as an unsteady phenomenon in terms of fluid dynamics. Therefore, the fluctuation of the liquid surface 16 does not form a clean sine wave waveform in which the fluctuations on the plus side and the minus side are equal. According to an experiment conducted by the inventor of the present application, the ripples of the refrigerant liquid surface 16 are not constant, and the fluctuation toward the negative side (lower side) is slower than the fluctuation toward the positive side (upper side). Has become. Therefore, the coolant level 1
The average position of 6 is slightly more negative than the simple average of the liquid surface positions on the plus side and the minus side (the average of the maximum value and the minimum value) in consideration of the above-described fluctuation time. Will be in.

Liquid level detection device 15 in the first embodiment
Is formed so that the above-mentioned erroneous detection of the liquid surface position due to the rocking of the refrigerant in the liquid reservoir 4 does not occur. That is, the controller 15b in the liquid level detection device 15
Is formed so as to correct the detection error of the liquid surface position due to the fluctuation of the refrigerant. Specifically, the sampling frequency in the liquid level detection device 15 is formed so as not to match the frequency of the oscillation on the liquid level. That is, when the sampling frequency in the liquid level detection device 15 and the swing frequency in the liquid level match, the detection data of the liquid level position always detects the same height of the swinging liquid level. Therefore, the liquid surface position is erroneously detected. As a method of not matching the sampling frequency in the liquid level detection device 15 and the oscillation frequency in the liquid level, for example, two frequencies that are not multiples (for example, 3 Hz and 5).
After sampling the liquid surface position at (Hz), there is a method of averaging the sampled data and using this value as the liquid surface position of the refrigerant. Further, as another method, for example, there is a method of increasing the detection time at the same sampling frequency (for example, the detection time is several minutes at 1 Hz).

More specifically, in the liquid level detection device 15, the number of data samples and the data processing method are determined in consideration of the fluctuation width and fluctuation frequency of the liquid level. The sampling number of data is set to, for example, 10 or several tens. Further, as a data processing method, for example, an average value of sampled data is obtained, and a value lower than the average value by about 20% is set as an actual detected value. Further, the position of the liquid surface 16 of the liquid reservoir 4 changes greatly when the compressor 1 in operation stops or the compressor 1 in operation stops. Therefore, in consideration of the operating state of the compressor 1, the liquid level detection device 1
Data sampling and data processing in 5 will be performed. For example, after a predetermined time (for example, 20 minutes) after the operation of the compressor 1, the liquid level detection device 15 samples the data.

As described above, even if the refrigerant fluctuates in the liquid reservoir 4, the liquid level detecting device 15 corrects the detection error of the position of the liquid surface 16, so that the refrigerant leaks in the refrigeration cycle device. There is no problem that it is determined that a refrigerant leak has occurred even though it has not occurred, or that a refrigerant leak has occurred but a refrigerant leakage has not occurred.

The relationship between the refrigerant used in the refrigeration cycle device and the detection accuracy of the liquid level detection device 15 shown in the first embodiment will be described below with reference to FIGS. 5 and 6. Figure 5
It is a correlation diagram which shows the change of the sound velocity of the ultrasonic wave which propagates a liquid refrigerant with respect to the temperature change of a liquid refrigerant. In the figure, the horizontal axis represents the temperature of the liquid refrigerant, and the vertical axis represents the sound velocity of ultrasonic waves propagating in the liquid refrigerant. Also, in the figure, the straight line marked with ■ is R
22 shows the temperature-sonic velocity characteristics of the refrigerant (conventional refrigerant), the straight line marked with Δ indicates the temperature-sonic velocity characteristics of the R404A refrigerant (alternative refrigerant), and the line marked with ● indicates the R407C refrigerant (alternative refrigerant). The temperature-sound velocity characteristic is shown. The R404A refrigerant and the R407C refrigerant have the standard composition ratio described above.

As shown in FIG. 5, R4 as an alternative refrigerant is used.
The 04A refrigerant has a temperature-sonic velocity characteristic having a gradient substantially equal to that of the conventional R22 refrigerant in the temperature range of 20 to 60 ° C. Here, the range of the temperature of 20 to 60 ° C. is the range of temperature change (operation range) of the liquid refrigerant in the liquid reservoir 4. Therefore, even when the conventional R22 refrigerant is used in the existing refrigeration cycle apparatus in which the liquid level detection device 15 is installed and even when it is necessary to replace the R22 refrigerant with the R404A refrigerant. Since the variation rate of the ultrasonic wave propagation speed with respect to the temperature change of the liquid refrigerant in the liquid reservoir 4 is almost unchanged, the same detection accuracy as before can be obtained without changing the settings related to the data processing of the liquid level detection device 15. Obtainable. That is, it is possible to provide the liquid level detection device 15 having high compatibility with the refrigerant replacement.

On the other hand, the R407C refrigerant as the alternative refrigerant has a temperature-sound velocity characteristic with less inclination than the conventional R22 refrigerant in the operating range. Therefore, by replacing the R22 refrigerant with the R407C refrigerant in the existing refrigeration cycle apparatus in which the liquid level detection device 15 is installed, the fluctuation rate of the ultrasonic wave propagation speed with respect to the temperature change of the liquid refrigerant in the liquid reservoir 4 is reduced. Therefore, the liquid level detection device 15
It is possible to improve the detection accuracy of the liquid surface 16 at.

The R407C refrigerant is a refrigerant used in a higher pressure state than the R22 refrigerant, but according to the liquid level detection device 15 in the first embodiment, the liquid level position is independent of the pressure level of the refrigerant. Since it is possible to detect the above, it is not necessary to change the condition setting (for countermeasures against pressure, etc.) accompanying the replacement of the refrigerant. A refrigerant that improves the detection accuracy of the liquid level detection device 15 corresponding to the R22 refrigerant is R407.
The refrigerant is not limited to the C refrigerant, and may be, for example, an HC refrigerant, a natural refrigerant, or the like as long as the gradient of the temperature-sound velocity characteristic is smaller than that of the R22 refrigerant.

FIG. 6 shows changes in the composition ratio of the liquid refrigerant.
It is a correlation diagram which shows the change of liquid density. In the figure, the horizontal axis represents the composition ratio of the liquid refrigerant, and the vertical axis represents the liquid density of the liquid refrigerant. Further, in the figure, the lower straight line shows the composition ratio-liquid density characteristic of the R404A refrigerant (alternative refrigerant), and the upper straight line shows the composition ratio-liquid density characteristic of the R407C refrigerant (alternative refrigerant). Here, the composition ratio of the liquid refrigerant on the horizontal axis is a value indicating how much R134A is mixed with the R404A refrigerant or the R407C refrigerant as the mixed refrigerant. The R404A refrigerant is a low boiling point refrigerant such as R125 and R1.
43A and R134A which is a high boiling point refrigerant. The R134A in the R404A refrigerant (pseudoazeotropic mixed refrigerant) having a standard composition ratio is 4 wt%. On the other hand, R
407C refrigerant is a low boiling point refrigerant R32 and R125,
It consists of a high boiling point refrigerant R134A. R in the standard composition ratio R407C refrigerant (non-azeotropic mixed refrigerant)
134A is 52 wt%.

Thus, the R404A refrigerant or R407
Since the R134A refrigerant contained in the C refrigerant has a higher boiling point than other composition refrigerants, the R404A refrigerant or R
When the 407C refrigerant is used in the temperature range between the low boiling point and the high boiling point, the low boiling point refrigerant is gasified and the composition ratio of R134A becomes high. However, R in R404A refrigerant
Since the composition ratio of 134A is low, even if the low boiling point refrigerant is gasified due to temperature change, the composition change of R134A with respect to the whole is small. Therefore, the change in liquid density of the R404A refrigerant is relatively small. On the other hand, since the composition ratio of R134A in the R407C refrigerant is high, when temperature change occurs and the low-boiling-point refrigerant is gasified, R13A with respect to the whole is
The composition change of 4A becomes large. Therefore, R407C
The change in the liquid density of the refrigerant is relatively large. Thus, R13
When the composition ratio of 4A fluctuates and the liquid density of the refrigerant fluctuates, the gas-liquid pressure difference in the liquid reservoir changes, and the liquid surface position in the liquid reservoir changes. Such a change in the liquid level position affects the detection accuracy of the liquid level detection device.

In the refrigeration cycle apparatus according to the first embodiment, the mixed refrigerant is controlled so that the fluctuation of the liquid surface position due to the composition fluctuation of the mixed refrigerant due to the temperature change falls within the detection accuracy range of the liquid surface detection apparatus. It was selected. For example, even if the detection accuracy of the liquid surface position by the liquid surface detection device is relatively rough, when the specifications of the refrigeration system are sufficiently satisfied, the liquid density of the liquid density with respect to the temperature change like the standard composition R407C refrigerant is changed. A mixed refrigerant having a relatively large change rate may be used. On the other hand, for example, when it is desired to improve the detection accuracy of the liquid surface position by the liquid surface detection device, a mixed refrigerant having a relatively small change rate of the liquid density with respect to the temperature change such as the standard composition R404A refrigerant is used. It will be. Also, an R407C refrigerant in which the composition ratio of R134A is set low may be used.

As described above, according to the liquid level detecting device 15 of the first embodiment, the liquid reservoir 4 can be retrofitted to the existing liquid reservoir 4 without performing any special processing such as drilling. Can be installed. In addition, refrigerant leakage in the refrigeration cycle can be detected early and reliably.

In the first embodiment, the liquid level detecting device 1 is considered in consideration of dust adhesion to the liquid level detecting device 15 and temperature rise of the liquid level detecting device 15 due to sunlight or the like.
5 was placed on the bottom of the liquid reservoir 4. On the other hand, when it is not necessary to consider the above influence, the liquid level detection device 15 can be installed on the ceiling surface of the liquid reservoir 4. However, in this case, unlike the first embodiment, the ultrasonic waves emitted from the transmitting unit 23 pass through the peripheral wall 14, the gas refrigerant, and the liquid refrigerant in this order, so the calculation processing in the controller 15b is set. Need to change.

Further, in the first embodiment, the liquid level detection device 15 is installed on the bottom surface of the liquid reservoir 4, but the liquid level detection device 15 may be installed on the side face of the liquid reservoir 4. In this case, a plurality of liquid level detection devices 15 are arranged vertically on the side surface of the liquid reservoir 4. Then, each of the plurality of liquid level detection devices 15 arranged in the vertical direction detects the presence or absence of the liquid refrigerant at the corresponding position, so that the liquid level position of the liquid refrigerant can be detected stepwise.

In addition, in the first embodiment, the liquid level detection device 15 in which the transmitter 23 and the receiver 24 are integrally formed is installed on the bottom surface of the liquid reservoir 4. On the other hand, the transmitter 23 and the receiver 24 of the liquid level detection device 15 can be separated. For example, the transmitter 23 is installed on the bottom surface of the liquid reservoir 4, and the receiver 24 is installed on the ceiling surface of the liquid reservoir 4. In this case, the reception unit 24 receives the ultrasonic waves that have sequentially passed through the peripheral wall 14, the liquid refrigerant, the gas refrigerant, and the peripheral wall 14.
Then, the liquid surface position is detected based on the length of the arrival time.

Further, in the first embodiment, the coolant leak detection device 13 is connected to the liquid level detection device 15, and the coolant leak detection is performed based on the detected value of the liquid level position transmitted from the liquid level detection device 15. The refrigerant leakage was judged in the device 13. On the other hand, the refrigerant leakage device 13 may be built in the liquid level detection device 15. Further, the refrigerant leakage detection device 13 is a medium (for example, a computing device, a personal computer, a human brain, etc.) that can judge the leakage of the refrigerant based on the value of the liquid surface position detected by the liquid surface detection device 15. , May be anything.

Further, in the first embodiment, the compressor 1
Even if the inverter is connected to and the rotation speed of the motor of the compressor 1 in operation fluctuates, the controller 15b of the liquid level detection device 15 corrects the influence of the fluctuation of the rotation speed of the compressor 1. can do. Specifically, when the rotation speed of the compressor 1 is reduced by the inverter, the flow rate of the refrigerant circulating in the refrigeration cycle is reduced,
Since the energy of the refrigerant colliding with the liquid surface 16 of the liquid reservoir 4 becomes small, the vertical fluctuation of the liquid surface 16 becomes small. On the other hand, when the rotation speed of the compressor 1 is increased by the inverter, the energy of the refrigerant colliding with the liquid surface 16 of the liquid reservoir 4 becomes large, so that the vertical fluctuation of the liquid surface 16 becomes large. Therefore, the liquid surface 1
An accurate liquid surface position can be detected by correcting the fluctuations of the six positions by the controller 15b of the liquid surface detection device 15 in association with the output data of the inverter.

Embodiment 2. The second embodiment of the present invention will be described in detail with reference to FIGS. FIG. 7 is a configuration diagram showing a refrigerant leakage detection system according to Embodiment 2 of the present invention. 8 is a schematic diagram showing a liquid level detection device and a remote monitoring unit in the refrigerant leakage detection system shown in FIG. The refrigerant leakage detection system according to the second embodiment is provided with a remote monitoring unit connected to the liquid level detection device 15 of the refrigeration cycle apparatus described in the first embodiment via a wired or wireless communication line. This is different from the first embodiment.

In FIG. 7, 15 is a liquid level detection device, and 17
Is a refrigerator (heat source device) equipped with the liquid reservoir 4, 18 is a showcase, 19 is a store such as a supermarket or a convenience store, 20 is a network, and 21 is a remote monitoring unit. Here, a plurality of showcases 18 are installed inside the store 19, and a refrigerator 17 is installed outside the store 19. The refrigerator 17 and the evaporator in the showcase 18 are connected by a high pressure liquid pipe 12 and a low pressure gas pipe 10. Further, the liquid reservoir 4 is arranged inside or in the vicinity of the refrigerator 17, and the liquid level detection device 15 is closely arranged on the peripheral wall of the liquid reservoir 4 as in the first embodiment.

Further, the liquid level detecting device 15 and the remote monitoring section 21
Are connected to each other via a telephone line or a mobile line. Although not shown, the remote monitoring unit 21 is
A display unit such as a T or a liquid crystal display and an input unit such as a keyboard, a mouse, and buttons are provided. The display unit of the remote monitoring unit 21 is the liquid level detection device 1 of the refrigeration cycle apparatus.
The data of No. 5 is acquired and displayed at a remote place. The input unit of the remote monitoring unit 21 operates the liquid level detection device 15 from a remote location.

In FIG. 8, 23 is a transmitter, 24 is a receiver, 25 is an ultrasonic wave generation circuit, 26 is a storage device, 27 is a timer, 28 is an arithmetic unit, 29 is a liquid crystal display, D
/ A converter or other output device, 44 is an A / D converter or other input device, 45 is a computing device, 46 is a liquid crystal display, D /
An output device such as an A converter, and a storage device 47 such as a memory. Here, the output device 29 of the liquid level detection device 15 and the input device 44 of the remote monitoring unit 21 are connected via a network 20 in a wired or wireless manner. The refrigerant leak detection device 13 may be built in the liquid level detection device 15 as described in the first embodiment, or may be connected between the liquid level detection device 15 and the network 20. It can also be built in the remote monitoring unit 21.

Next, the operation of the refrigerant leakage detection system according to the second embodiment will be described. The operation of the refrigeration cycle device installed inside and outside the store 19 and the operation of the liquid level detection device 15 are the same as those in the first embodiment, and therefore the description thereof is omitted. First, the remote monitoring unit 2
From 1, a command signal is transmitted to the ultrasonic wave generation circuit 25 of the liquid level detection device 15 via a line. As a result, the transmitter 23 of the liquid level detection device 15 is operated to generate ultrasonic waves. Then, the receiving section 24 receives the ultrasonic wave reflected by the interface of the medium, and sends the signal to the arithmetic unit 28. The data processed by the arithmetic unit 28 is transmitted to the output unit 29. The data of the output device 29 is the information about the refrigerant liquid level in the liquid reservoir 4 detected (measured) by the liquid level detection device 15 and the refrigerant leakage obtained based on the liquid level.

Then, this information is transmitted via the line to the input device 44 of the remote monitoring unit 21 installed in the management headquarters of the store 19 or the facility management company. Input device 4
The data transmitted to the data No. 4 is subjected to calculation by the calculation device 45, and then output by the output device 46. Further, the data calculated by the calculation device 45 is
It is also transmitted to the storage device 47. The storage device 47 stores the current and past refrigerant liquid surface positions, the condensation temperature, the evaporation temperature,
Data such as presence / absence of refrigerant leakage and refrigerant leakage amount are accumulated.

As described above, according to the refrigerant leakage detection device of the second embodiment, similar to the first embodiment, the liquid reservoir 4 does not have to be specially processed such as a hole.
The liquid level detecting device 15 can be installed after the existing liquid reservoir 4. Further, since it is possible to monitor the occurrence status of refrigerant leakage of the refrigeration cycle device at a remote place away from the store 19, it is possible to detect the refrigerant leakage of the refrigeration cycle early and surely and perform appropriate maintenance. it can.

In the second embodiment, bidirectional transmission of information is possible using the communication line between the liquid level detection device 15 and the remote monitoring section 21. On the other hand, the information can be transmitted only in one direction. For example, the liquid level detection device 1
The liquid level position in 5 is detected by the controller 15b installed in the liquid level detector 15 without using a communication line.
It is done regularly. Then, the detection data of the liquid level detection device 15 can be transmitted to the remote monitoring unit 21 via the communication line.

Third Embodiment The third embodiment of the present invention will be described in detail with reference to FIG. FIG. 9 is a configuration diagram showing a refrigerant leakage detection system according to Embodiment 3 of the present invention. The refrigerant leakage detection system according to the third embodiment is
The difference from the second embodiment is that a plurality of refrigeration cycle devices are connected to the network 20.

In FIG. 9, 15 is a liquid level detection device, and 17
Is a plurality of refrigerators, 18 is a showcase connected to each of the refrigerators 17, 19 is a plurality of stores, 20 is a network, and 21 is a remote monitoring unit. Here, a plurality of showcases 18 are installed in each of the plurality of stores 19, and a refrigerator 17 is installed outside each of the stores 19. Further, the plurality of refrigeration cycle devices are networked, and each liquid level detection device 15 and
The remote monitoring unit 21 is connected via the network 20. Then, the remote monitoring unit 21 operates the input unit to operate the liquid level detection device 15 in the desired refrigeration cycle device, and monitors the data of the liquid level detection device 15 in the desired refrigeration cycle device on the display unit. . The operation of the refrigerant leakage detection system in the third embodiment is the same as that in the second embodiment except that the remote monitoring unit 21 monitors a plurality of refrigeration cycle devices.

As described above, according to the refrigerant leakage detection device of the third embodiment, as in the above-described respective embodiments, the liquid reservoir 4 does not need to be subjected to any special processing such as drilling.
The liquid level detecting device 15 can be installed after the existing liquid reservoir 4. In addition, since it is possible to collectively monitor the occurrence of refrigerant leakage in a plurality of refrigeration cycle devices at a remote location away from the store 19, the refrigerant leakage in a plurality of refrigeration cycles can be detected early and reliably and efficiently. Therefore, appropriate maintenance can be performed.

In each of the above embodiments, the ultrasonic wave is used as the propagating wave emitted from the liquid level detecting device 15, but a light wave may be used instead. In this case, a part of the peripheral wall 14 of the liquid reservoir 4 is formed of a transparent material such as glass capable of propagating a light wave, and the transmitting part and the receiving part of the liquid level detection device 15 are installed in the transparent part. . Also in this case, substantially the same effects as those of the above-described respective embodiments are exhibited.

Further, "refrigeration cycle device" in the present specification
The term is used in a broad sense including all devices that circulate a refrigerant to perform heat exchange, for example, devices such as an air conditioner and a heat pump.

It should be noted that the present invention is not limited to the above-mentioned respective embodiments, and the respective embodiments can be appropriately modified within the scope of the technical idea of the present invention, in addition to those suggested in the respective embodiments. That is clear. Also, the number of the above-mentioned constituent members,
The position, shape, etc. are not limited to those in the above-described embodiment, and can be any number, position, shape, etc. suitable for carrying out the present invention.

[0089]

EFFECTS OF THE INVENTION Since the present invention is configured as described above, it is possible to retrofit an existing liquid pool without modifying the liquid pool for installation, and to prevent refrigerant leakage in the refrigeration cycle. Highly installable and reliable liquid level detector, liquid pool, refrigeration cycle device, refrigerant leak that can be detected early and is highly compatible with different types of refrigerant, and can reliably detect the amount of refrigerant in the liquid pool. A detection system and a liquid level detection method can be provided.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a refrigeration cycle device according to a first embodiment of the present invention.

FIG. 2 is a Mollier diagram showing the operation of the refrigerant in the refrigeration cycle device of FIG.

FIG. 3 is a schematic view showing a liquid reservoir in the refrigeration cycle device of FIG.

FIG. 4 is a schematic view showing a liquid level detection device in the liquid reservoir of FIG.

FIG. 5 is a correlation diagram showing changes in the speed of sound with respect to changes in the temperature of the refrigerant.

FIG. 6 is a correlation diagram showing a change in liquid density with respect to a change in the composition ratio of the refrigerant.

FIG. 7 is a configuration diagram showing a refrigerant leakage detection system according to a second embodiment of the present invention.

8 is a schematic diagram showing a liquid level detection device and a remote monitoring unit in the refrigerant leakage detection system of FIG.

FIG. 9 is a configuration diagram showing a refrigerant leakage detection system according to a third embodiment of the present invention.

FIG. 10 is a configuration diagram showing a conventional refrigeration cycle apparatus.

FIG. 11 is a configuration diagram showing another conventional refrigeration cycle apparatus.

FIG. 12 is a diagram showing the sound velocity of ultrasonic waves propagating in a typical medium.

[Explanation of symbols]

1 compressor, 2 condenser, 3 blower for condenser,
4 Liquid Reservoir, 5 Solenoid Valve, 6 Pressure Reduction Device, 7 Evaporator, 8 Fan for Evaporator, 9 High Pressure Gas Pipe, 10
Low-pressure gas pipe, 11 high-pressure liquid pipe, 12 high-pressure liquid pipe, 13 refrigerant leakage detection device, 14 peripheral wall, 15
Liquid level detection device, 15a ultrasonic sensor, 15b controller, 16 liquid level, 17 refrigerator, 18 showcase, 19 stores, 20 network, 21
Remote monitoring unit, 23 transmitting unit, 24 receiving unit, 25
Ultrasonic wave generation circuit, 26 storage device, 27 timer, 28 arithmetic device, 29 output device, 30 temperature detector, 44 input device, 45 arithmetic device, 46
Output device, 47 storage device.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G01F 23/28 G01F 23/28 SR J H (72) Inventor Hiroshi Nakata 2-2 Marunouchi, Chiyoda-ku, Tokyo No. 3 F term in Sanryo Electric Co., Ltd. (reference) 2F014 FA01 FA03 FB01 FB04

Claims (20)

[Claims] 1. A liquid level detecting device for detecting a liquid level position of a refrigerant stored in a liquid pool installed in a refrigeration cycle, the liquid level detecting device being arranged to pass through a peripheral wall of the liquid pool from the outside of the liquid pool. A transmitting unit that emits a propagating wave that is incident on the liquid surface of the refrigerant, and a receiving unit that receives the propagating wave that is reflected or transmitted by the liquid surface and then passes through the peripheral wall and is emitted to the outside of the liquid reservoir. A liquid level detection device characterized in that 2. The liquid level detection device according to claim 1, wherein the liquid level detection device is detachably installed on a peripheral wall of the liquid reservoir. 3. The liquid level detection device according to claim 1, wherein leakage of the refrigerant from the refrigeration cycle is detected based on the detected value of the liquid level position. 4. The propagating wave is an ultrasonic wave, and a controller is provided for determining the liquid surface position based on a time from when the ultrasonic wave is emitted from the transmitting unit to when it reaches the receiving unit. The liquid level detection device according to any one of claims 1 to 3. 5. The liquid level detection device according to claim 4, wherein the controller is formed so as to be able to correct a liquid level position detection error due to the fluctuation of the refrigerant in the liquid reservoir. 6. A temperature detector for detecting the temperature of the refrigerant in the liquid reservoir and / or the temperature of the peripheral wall, the controller further comprising a temperature detector for detecting the temperature of the refrigerant and / or the temperature of the peripheral wall. The liquid level position of the refrigerant is obtained based on a detection value detected by the temperature detector and data of the storage device corresponding to the detection value. The liquid level detection device according to claim 4 or 5. 7. The liquid level detection device according to claim 4, wherein the refrigerant has a smaller change in propagation velocity with respect to a temperature change than the R22 refrigerant. 8. The refrigerant is a mixed refrigerant composed of a plurality of kinds of refrigerants, and the fluctuation of the liquid surface position due to the fluctuation of the composition ratio of the refrigerant due to the temperature change causes the detection accuracy of the liquid surface position. The liquid level detection device according to any one of claims 4 to 7, wherein the liquid level detection device is configured to have a composition within the range. 9. The liquid level detection according to claim 1, wherein the propagating wave is a light wave, and the peripheral wall includes a transparent portion through which the light wave can pass. apparatus. 10. A liquid pool comprising the liquid level detection device according to claim 1. 11. A refrigeration cycle apparatus comprising the liquid reservoir according to claim 10. 12. A refrigerant leakage detection system, comprising: a remote monitoring unit for acquiring data of the liquid level detection device in the refrigeration cycle apparatus according to claim 11 via a communication line. 13. The refrigerant leakage detection system according to claim 12, wherein the remote monitoring unit detects the liquid level position by the liquid level detection device via the communication line. 14. The refrigerant leakage detection system according to claim 12, wherein the refrigeration cycle device is a plurality of refrigeration cycle devices networked together. 15. A refrigerant leakage detection device for detecting leakage of refrigerant from the refrigeration cycle based on the liquid level position detected by the liquid level detection device, wherein data of the liquid level detection device is the refrigerant leakage. The refrigerant leakage detection system according to any one of claims 12 to 14, which is transmitted to the remote monitoring unit via a detection device. 16. A liquid level detecting method for detecting a liquid level position of a refrigerant stored in a liquid reservoir installed in a refrigeration cycle, wherein ultrasonic waves are applied from the outside of the liquid reservoir toward the liquid surface of the refrigerant. And a step of receiving the ultrasonic wave reflected or transmitted by the liquid surface outside the liquid reservoir, and a liquid surface of the refrigerant based on the time from transmitting the ultrasonic wave to receiving the ultrasonic wave. And a step of detecting the position. 17. The liquid surface according to claim 16, wherein the step of detecting the liquid surface position includes a step of correcting a detection error of the liquid surface position due to the fluctuation of the refrigerant in the liquid reservoir. Detection method. 18. The method further comprises the step of detecting the temperature of the refrigerant and / or the peripheral wall, wherein the step of detecting the liquid surface position includes the propagation of the ultrasonic wave based on the detection value detected by the step of detecting the temperature. 18. The liquid level detection method according to claim 16 or 17, further comprising the step of obtaining a velocity. 19. The method according to claim 16, further comprising the step of detecting leakage of the refrigerant from the refrigeration cycle based on the liquid surface position detected in the liquid surface position detecting step. Item 19. The liquid level detection method according to any one of Items 18. 20. The step of detecting the leakage of the refrigerant comprises a theoretical amount of liquid refrigerant that is obtained by subtracting the amount of circulating refrigerant circulating in the refrigeration cycle from the amount of refrigerant charged in the refrigeration system, and the liquid level position. 20. The liquid level detecting method according to claim 19, wherein the liquid level detecting method comprises a step of comparing with an actual amount of the liquid pool refrigerant obtained based on the liquid level position detected in the step of detecting.