JP6067255B2 - Refrigerant recovery device and refrigerant recovery method - Google Patents

Description

  The present invention relates to a refrigerant recovery apparatus and a refrigerant recovery method for recovering and processing refrigerant and refrigeration oil used in, for example, a refrigeration air conditioner.

  Conventionally, chlorofluorocarbons and fluorocarbons are used as refrigerants used in vapor compression refrigeration air conditioners such as air conditioners because of their thermal properties and chemical stability. These refrigerants destroy the ozone layer and have a great global warming effect. Therefore, when the product is repaired or when the product is used, the refrigerant is collected and detoxified. .

  In particular, small refrigeration air conditioners such as home air conditioners often use a hermetic compressor to prevent leakage of the refrigerant in use, and the refrigeration oil that serves as the lubricating oil for the compressor is the refrigerant. At the same time, it is enclosed in a refrigeration circuit. Since refrigeration oil lubricates the compressor mechanism while circulating in the refrigeration circuit together with the refrigerant, oil having solubility with the refrigerant is often used. In order to recover the refrigerant dissolved in the refrigeration oil when the refrigerant is recovered from the product, methods such as simultaneously extracting the refrigerant and the refrigeration oil from the product are performed (see Patent Document 1).

Japanese Unexamined Patent Publication No. 09-152233 (FIG. 7)

  In recent years, countermeasures against global warming have been studied in various fields, and refrigerants used in refrigeration and air-conditioning equipment have also been recovered and properly treated, so they can be replaced with substances that have less impact on global warming. Is also being considered.

  Currently, the refrigerant used in home air conditioners is a mixture of R-32A (CH2F2: difluoromethane) and R-125 (C2HF5: pentafluoroethane) called R-410A. This R-410A has a GWP (Global Warming Potential: coefficient when the global warming impact of CO2 is 1), which is an index of the global warming impact, of 2,088, and has a great impact on global warming. Therefore, R-32 (GWP: 675), 1234yf, 1234ze (both C3H2F4: tetrafluoropropene, GWP is 1234yf is 4, 1234ze is 9) and mixtures thereof as an alternative to R-410A. Yes.

  However, these alternative substances are substances that are flammable in the atmosphere. In addition, these alternative substances are sometimes referred to as slightly flammable because they have lower combustibility and a smaller combustible range than propane (C3H8) and butane (C4H10) used as fuel gas. However, many refrigerants that have been sealed in refrigeration and air-conditioning apparatuses so far are nonflammable, and in the application of these alternative substances (alternative refrigerants), a function for an unexpected situation is desired.

  Among them, although R-32 has a small GWP, it is considered that recovery and proper processing are indispensable when the apparatus is repaired or used. Since the recovery operation of the refrigerant can be an opportunity for the refrigerant to come into contact with the atmosphere, the recovery device and the recovery method need a measure for suppressing the deterioration of an unexpected situation.

  In the refrigerant recovery operation, the recovered refrigerant is compressed, cooled and liquefied, and stored in a dedicated cylinder. On the other hand, when the refrigerating machine oil recovered at the same time is discharged, the conventional refrigerant recovery apparatus has a problem that the refrigerating machine oil in a state where some refrigerant is dissolved is discharged into the atmosphere. For this reason, a mechanism for reducing the refrigerant dissolution amount of the refrigerating machine oil to be discharged, a mechanism for discharging the refrigerating machine oil in a state separated from the refrigerant, and the like are required.

  Generally, it is conceivable to use an inert gas such as nitrogen or argon for discharging the recovered refrigeration oil. However, if these inert gases are used in a sealed space, there is a risk of creating a suffocating environment. Because it is not realistic.

  The present invention has been made in order to solve the above-described problems. When recovering refrigerant and refrigerating machine oil from a refrigerating and air-conditioning apparatus using a refrigerant exhibiting flammability in the atmosphere, an unexpected situation is unlikely. It is intended to provide a refrigerant recovery apparatus and a refrigerant recovery method that reduce the deterioration of the temperature.

The refrigerant recovery apparatus according to the present invention is supplied with a mixed liquid of refrigerant and refrigerating machine oil, and is connected to the gas-liquid separator that separates the refrigerant from the mixed liquid by negative pressure, and the gas-liquid separator. A compressor that generates a negative pressure therein, discharges the refrigerant separated in the gas-liquid separator, recovers and compresses the refrigerant, and a heat exchange device that cools and liquefies the compressed refrigerant And a refrigerant discharge unit having a refrigerant discharge unit that is connected to the gas-liquid separator and stays in the gas-liquid separator and in which at least a part of the refrigerant is separated is provided to be discharged out of the gas-liquid separator. The refrigerating machine oil discharge unit and the refrigerating machine oil discharge unit connected to the gas-liquid separator, sending dry air having a humidity of 5 g / kg or less into the gas-liquid separator and separating at least a part of the refrigerant And a dry air supply unit for discharging the gas-liquid separator to the outside. Characterized in that was.

According to the refrigerant recovery apparatus of the present invention, in the gas-liquid separator to which the mixed liquid of the refrigerant and the refrigerating machine oil is supplied, the refrigerant is separated from the mixed liquid by the negative pressure generated by the compressor of the refrigerant discharge unit. In the refrigerant discharge section connected to the gas-liquid separator, the compressor discharges the refrigerant separated in the gas-liquid separator, collects and compresses it, and the heat exchange device compresses it in the compressor The cooled refrigerant is cooled and liquefied. The refrigerating machine oil that is connected to the gas-liquid separator and is refrigerating machine oil that stays in the gas-liquid separator and in which at least a part of the refrigerant is separated can be discharged out of the gas-liquid separator. Connected to the discharge unit and the gas-liquid separator, the dry air having a humidity of 5 g / kg or less is fed into the gas-liquid separator, and the refrigerating machine oil in a state where at least a part of the refrigerant is separated is removed via the refrigerating machine oil discharge unit. Since it is equipped with a dry air supply unit that is discharged outside the liquid separator, the flammable refrigerant is recovered from the refrigerating air conditioner together with the refrigerating machine oil, and the unexpected situation is worsened when the refrigerating machine oil is discharged from the collecting apparatus. Can be reduced. Moreover, even if the refrigerant leaks from the refrigerant recovery device, it is possible to reduce the deterioration of the situation that may occur.

It is a figure which shows the structure of the refrigerant | coolant collection | recovery apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows an example of the ignition experiment apparatus of the liquid mixture with which collection | recovery is assumed with the refrigerant | coolant collection method which concerns on Embodiment 1 of this invention, (a) is a figure which shows ignition experiment preliminary processing, (b) is an ignition experiment. It is a figure which shows an apparatus. It is a table | surface which shows the ignition test result of the liquid mixture with which collection | recovery is assumed with the refrigerant | coolant collection method which concerns on Embodiment 1 of this invention. It is a figure which shows the structure of the refrigerant | coolant collection | recovery apparatus for comparison with the refrigerant | coolant collection | recovery apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the structure of the refrigerant | coolant collection | recovery apparatus which concerns on Embodiment 2 of this invention. It is a figure which shows the structure of the refrigerant | coolant collection | recovery apparatus which concerns on Embodiment 3 of this invention. It is a figure which shows the refrigerant | coolant collection method which concerns on Embodiment 4 of this invention.

Embodiment 1 FIG.
1 is a diagram illustrating a configuration of a refrigerant recovery apparatus according to Embodiment 1. FIG. The configuration of the refrigerant recovery apparatus and the refrigerant recovery method using the refrigerant recovery apparatus according to the present embodiment will be described with reference to FIG.

  The refrigerant recovery apparatus 11 is a refrigerant processing apparatus that recovers and processes refrigerant and refrigeration oil from a product to be recovered using a refrigeration cycle in which refrigerant and refrigeration oil that is lubricating oil are enclosed. The product to be collected using the refrigeration cycle is, for example, a refrigeration air conditioner such as an air conditioner.

  As shown in FIG. 1, the refrigerant recovery apparatus 11 includes a gas-liquid separation container 14, a dehumidifying device integrated valve 15, a refrigerator oil discharge port 16, a vacuum pump 17, a compressor 18, an oil separator 19, a heat exchange device 100, and a refrigerant storage. A container 111 and a switching valve 112 are provided.

  First, referring to FIG. 1, the refrigerant is separated from the mixed liquid of the refrigerant and the refrigerating machine oil, discharged from the gas-liquid separation container 14, and recovered by the refrigerant recovery apparatus 11 that recovers the discharged refrigerant in the refrigerant recovery cylinder 12. The refrigerant separation / recovery process (refrigerant discharge process) of the refrigerant recovery method will be described.

  The refrigerant recovery device 11 is a gas-liquid separation container 14 that stores a mixed liquid of refrigerant and refrigeration oil, and evaporates and separates at least a part of the refrigerant from the mixed liquid stored in the gas-liquid separation container 14, The gas-liquid separation container 14 (an example of a gas-liquid separator) which discharges the evaporated gaseous refrigerant | coolant with the compressor 18 grade | etc., Is provided. Here, the compressor 18 etc. which discharge a refrigerant | coolant are an example of a refrigerant | coolant discharge part.

  More specifically, the refrigerant recovery device 11 sucks the refrigerant and the refrigerating machine oil in a mixed state from the outdoor unit of an air conditioner that is a product to be collected through the suction port 13 and stores the refrigerant in the gas-liquid separation container 14.

  Since the inside of the gas-liquid separation container 14 is in a negative pressure state by the compressor 18, only the refrigerant evaporates from the mixed liquid of the refrigerant and the refrigerating machine oil. The evaporated gas refrigerant is further separated by the oil separator 19.

  The gas refrigerant that has passed through the oil separator 19 is taken into the compressor 18 via the switching valve 112 and is compressed by the compressor 18 to be in a high temperature and high pressure state, and then cooled and liquefied by the heat exchange device 100. The cooled and liquefied refrigerant is stored in the refrigerant storage container 111 and then enclosed in the refrigerant recovery cylinder 12.

  As described above, the refrigerant is separated and recovered from the mixed liquid of the refrigerant and the refrigerating machine oil. At this time, what remains in the gas-liquid separation container 14 is the refrigeration oil in a state where the refrigerant is separated, but some refrigerant may remain. Therefore, it can be said that the refrigeration oil that stays in the gas-liquid separation container 14 is in a state where at least a part of the refrigerant is separated.

  Next, the refrigerating machine oil discharge process (refrigerating machine oil discharge process) of the refrigerant recovery method by the refrigerant recovery apparatus 11 that discharges the refrigerating machine oil will be described.

  The refrigerant recovery device 11 includes a refrigerating machine oil discharge port 16 (an example of a refrigerating machine oil discharge unit) that discharges refrigerating machine oil (mixed liquid) in a state where at least a part of the refrigerant has evaporated. Further, the refrigerant recovery device 11 sends dry air to the gas-liquid separation container 14, and the refrigerating machine oil in a state where at least a part of the refrigerant stored in the gas-liquid separation container 14 is evaporated by the pressure of the supplied dry air. A dehumidifying device integrated valve 15 (an example of a dry air supply unit) that discharges from the refrigerator oil discharge port 16 is provided.

  The refrigerator oil discharge processing method will be described in detail below. The refrigerating machine oil left in the gas-liquid separation container 14 is placed in a negative pressure atmosphere for a certain period of time, so that the refrigerant is sufficiently removed. Therefore, as described above, “a refrigerating machine oil in which at least a part of the refrigerant has evaporated” is a refrigerating machine oil in which the refrigerant has been sufficiently removed, but it cannot be said that the refrigerant has been completely removed from the refrigerating machine oil. Is.

  After removing the refrigerant by the refrigerant separation and recovery method described above, the suction side switching valve 112 of the compressor 18 and the suction port 13 of the gas-liquid separation container 14 are closed. And the dehumidification device integrated valve 15 attached to the upper part of the gas-liquid separation container 14 is opened, and dry air is introduced into the gas-liquid separation container 14.

  Here, when the refrigerating machine oil discharge port 16 is opened, the refrigerating machine oil in the gas-liquid separation container 14 (that is, “freezing in which at least a part of the refrigerant has evaporated” is caused by the pressure of the dry air introduced into the gas-liquid separation container 14. Machine oil ”) is discharged from the refrigerator oil discharge port 16. In other words, by replacing the refrigeration oil in the gas-liquid separation container 14 (ie, “refrigeration oil in which at least a part of the refrigerant has evaporated”) with the dry air introduced into the gas-liquid separation container 14, the refrigeration oil (ie, , “Refrigerating machine oil in which at least a part of the refrigerant is evaporated”) is discharged from the refrigerant recovery device 11.

  The dehumidifying device integrated valve 15 includes a dehumidifying device that dehumidifies gas, dehumidifies the surrounding air by the dehumidifying device, and sends the dehumidified surrounding air to the gas-liquid separation container 14 as dry air. The moisture adsorbing substance of the dehumidifying device at this time may be any material that adsorbs moisture such as silica gel, slaked lime, zeolite, activated carbon, etc., and may be a freezing and dehumidifying device such as a Peltier device.

  After all the refrigerating machine oil is discharged from the gas-liquid separation container 14, the refrigerating machine oil discharge port 16 is closed, and the provided vacuum pump 17 (an example of an air discharge unit) is operated to fill the gas-liquid separation container 14 filled with dry air. Exhaust inside. After the gas-liquid separation container 14 is evacuated, the recovery operation of the refrigerant and the refrigerating machine oil is started again. That is, the mixed liquid of the refrigerant and the refrigerating machine oil is sucked from the suction port 13, and the refrigerant separation and recovery process step and the refrigerating machine oil discharge process step are executed.

  By working according to the above procedure, the refrigerant is sufficiently removed from the refrigeration oil recovered by the refrigerant recovery device 11, and the refrigeration oil is released to atmospheric pressure in an atmosphere of dry air. That is, even if a small amount of refrigerant remains in the refrigerating machine oil, it is released in an atmosphere of dry air.

  In addition, since air is a non-condensable gas, the pressure does not drop sufficiently even if cooling is performed by the heat exchange device 100 when mixed in the liquefaction process of the refrigerant, and the inside of the refrigerant storage container 111 and the refrigerant recovery cylinder 12 Since the pressure rises, continuous refrigerant recovery becomes difficult. However, since the dry air in the gas-liquid separation container 14 is exhausted to the outside by the vacuum pump 17 after the refrigerating machine oil is discharged, the refrigerant recovery can be continued without being mixed into the refrigerant compression and liquefaction process. .

  The refrigerant | coolant of the to-be-collected product mentioned above is R-32, 1234yf, 1234ze, ammonia, etc. which show slight flammability, for example. Hereinafter, an example of an experiment showing that moisture in the air greatly affects the ignition and combustion behavior of these R-32, 1234yf, 1234ze, ammonia and the like will be described.

  FIG. 2 is a diagram showing an example of a mixed liquid ignition experiment apparatus that is assumed to be recovered by the refrigerant recovery method according to the first embodiment. FIG. 2A is a diagram showing an ignition experiment preliminary process. b) is a diagram showing an ignition experimental apparatus. FIG. 3 is a table showing the ignition test results of the mixed liquid assumed to be recovered by the refrigerant recovery method according to the first embodiment.

  In order to grasp the actual behavior of the refrigerating machine oil (mixed liquid) in which the refrigerant was dissolved, the ignition behavior was confirmed with the ignition experimental apparatus shown in FIG.

  First, the preliminary process shown in FIG. As a pretreatment, a refrigerating machine oil in which a refrigerant was dissolved was produced. 50 cc of refrigerating machine oil was sealed in an autoclave 21 having an internal capacity of 100 cc, and after sufficiently deaerated with a vacuum pump, R-32 was sealed from the R-32 cylinder 20 through the regulator 22.

  At this time, a general VG (viscosity grade) 32 refrigerant ester oil (pentaerythritol type polyol ester) was used as the refrigerating machine oil. The set value of the regulator 22 was set to 90 kpa · abs, which is slightly higher in pressure than a normal refrigerant recovery machine. The container (autoclave 21) was allowed to stand for about one night in a room temperature-controlled at 25 ° C., and then subjected to an ignition experiment.

  Next, an ignition experiment performed with the ignition experiment apparatus shown in FIG. In the ignition experiment, a series of ignition experiment devices were installed in a draft chamber so as to be almost sealed. The inside of the draft chamber was replaced with dry air in advance, and the humidity was adjusted by the nebulizer 26.

  The refrigerating machine oil adjusted by the pretreatment is taken out from the autoclave 21, put in the refrigerating machine oil container 24 on the hot plate 23, and the ignition source installed about 100 mm above the liquid level of the refrigerating machine oil while raising the temperature of the hot plate 23. The combustion state in the vicinity of 25 was visually observed. An arc discharge terminal was used as the ignition source 25, and the discharge energy was adjusted by a transformer to about 15 kv and 20 mA, and discharge was performed for about 1 second every about 10 seconds. The temperature setting of the hot plate 23 was 70 ° C. Observation was performed for a certain period of time from the start of temperature rise to about 10 minutes after reaching 70 ° C.

  As shown in the experimental result table of FIG. 3, the result of the above-described ignition experiment shows that the smaller the amount of moisture in the surrounding air, the smaller the fired flame. In either case, however, the flame was observed only during the discharge, and did not become a continuous flame, and did not reach the oil level of the refrigerator. In this experiment, the slightly flammable refrigerant dissolved in the refrigeration oil was vaporized and ignited as the temperature of the refrigeration oil increased, but it reproduced the influence of ambient moisture on the combustion of the refrigerant at a practical level. In addition, since it is a refrigerant with low flammability, the flow of ambient air has a great influence on the generation and growth of flames, so the state in the draft chamber is sufficiently stabilized for highly reproducible experiments. It is important to make it happen. The same behavior was exhibited with other slightly flammable refrigerants such as 1234yf, 1234ze, and ammonia.

  From the above experimental results, it can be said that if the moisture content in the air is low, the deterioration can be suppressed even when an unexpected situation such as refrigerant leakage or ignition occurs. That is, it is understood that it is important to manage the amount of moisture in the air around the refrigerant and refrigerating machine oil. However, the numerical values shown in the experimental result table of FIG. 3 vary depending on the temperature conditions in this experiment, the type of refrigerant, refrigerating machine oil, and the like, and humidity management according to individual conditions is required.

  FIG. 4 is a diagram illustrating a configuration of a refrigerant recovery apparatus for comparison with the refrigerant recovery apparatus 11 according to the first embodiment. As shown in FIG. 4, the refrigerant recovery device 90 for comparison often uses the vapor pressure of the recovered refrigerant in order to easily discharge the recovered refrigeration oil to atmospheric pressure. That is, the refrigerant having a pressure equal to or higher than the atmospheric pressure recovered through the refrigerant return pipe 61 is returned into the gas-liquid separation container 14 having a negative pressure, and the refrigerating machine oil is discharged from the refrigerant recovery device 90 at that pressure. Accordingly, the refrigerant is also discharged into the atmosphere together with the refrigerating machine oil, and a combustible region due to the refrigerant exists in the vicinity of the refrigerating machine oil discharge port 16. Also, exposure to high-pressure refrigerant causes the refrigerant to dissolve again in the refrigerating machine oil and gradually evaporate after being released to atmospheric pressure. Will remain a risk to unforeseen circumstances.

  In the refrigerant recovery apparatus 90 for comparison, when the refrigerator oil discharge port 16 is measured with a refrigerant sensor, it is confirmed that a high-concentration refrigerant is discharged, and the refrigerant amount in the discharged refrigerator oil is 2 to 10 wt. %Met.

  On the other hand, as a result of the refrigerant recovery operation in the refrigerant recovery apparatus 11 according to the present embodiment, the refrigerant in the discharged refrigeration oil is less than 1 wt%, and measurement is performed by the refrigerant sensor in the vicinity of the refrigeration oil discharge port 16. No refrigerant was detected. Furthermore, since the refrigerating machine oil is discharged in a state of being wrapped in dry air, in the unlikely event that an ignition source exists near the refrigerating machine oil discharge port 16, Deterioration can be suppressed.

  As described above, the refrigerant recovery apparatus 11 according to the present embodiment extracts the refrigerant and the refrigerating machine oil from the refrigerating and air-conditioning equipment that uses the flammable refrigerant in the atmosphere, and removes the refrigerant and the refrigerating machine oil from the gas and liquid. A refrigerant recovery apparatus having a separation mechanism is characterized in that refrigeration oil staying in a gas-liquid separation container having a negative pressure is discharged under atmospheric pressure by replacing with dry air.

  Further, the refrigerant recovery apparatus 11 according to the present embodiment is characterized in that the dry air sealed in the gas-liquid separation container is generated from the surrounding air by passing through the dehumidifying device integrated with the valve. .

  Further, the refrigerant recovery device 11 according to the present embodiment has a mechanism for exhausting dry air in the gas-liquid separation container.

  The refrigerant recovery apparatus 11 according to the present embodiment can be applied to a flammable refrigerant heavier than air. In particular, when the flammable refrigerant is difluoromethane, tetrafluoropropene, or a mixture containing any one of these, the effect that it is possible to suppress the worsening of an unexpected situation becomes remarkable.

Embodiment 2. FIG.
FIG. 5 is a diagram illustrating a configuration of the refrigerant recovery apparatus according to the second embodiment. FIG. 5 is a diagram corresponding to FIG. 1 described in the first embodiment, and the same functional configuration as that in FIG.

  5 is different from FIG. 1 in that an air compressor 31 for feeding dry air into the gas-liquid separation container 14 is provided. That is, the refrigerant recovery apparatus 11 a according to the present embodiment supplies the dry air sealed in the gas-liquid separation container 14 by the air compressor 31. Therefore, the refrigerant recovery apparatus 11a according to the present embodiment does not include the dehumidification device integrated valve 15 included in the refrigerant recovery apparatus 11 of FIG.

  The refrigerant recovery apparatus 11a according to the present embodiment includes an air compressor 31 that generates dry air. The air compressor 31 sucks ambient air, generates dry air by condensing and separating moisture in the sucked ambient air, and sends the generated dry air to the gas-liquid separation container 14. The air compressor 31 is an example of a dry air supply unit.

  Moisture in the atmosphere is condensed and separated in the compression process by the air compressor 31 and discharged through the condensed water drain 32, so that dry air can be easily generated. Generation of dry air using a dehumidifying device requires periodic replacement of dehumidifying substances and regeneration treatment, but with this method, only drain water needs to be discharged. Further, since high-pressure dry air can be introduced into the gas-liquid separation container 14, the refrigerating machine oil recovered at high speed can be discharged.

  In the refrigerant recovery device 11a shown in FIG. 5, the vacuum pump 17 is used for exhausting the gas-liquid separation container 14 after discharging the refrigerating machine oil, as in the refrigerant recovery device 11 shown in FIG. However, the air compressor 31 may have a function (pump) having both functions of an air compressor and a vacuum pump. If the air compressor 31 is such a pump, it is also possible to combine intake and exhaust with a single pump by connecting the suction port of the pump to the gas-liquid separation container 14 and arranging the valves appropriately.

Embodiment 3 FIG.
FIG. 6 is a diagram illustrating a configuration of the refrigerant recovery apparatus according to the third embodiment. FIG. 6 is a diagram corresponding to FIG. 5 described in the second embodiment. The same functional components as those in FIG. 5 are denoted by the same reference numerals, and the description thereof is omitted.

  6 is different from FIG. 5 in that the vacuum pump 17 is not provided. As shown in FIG. 6, the refrigerant recovery device 11 b includes a switching valve 112 a at the discharge port of the compressor 18. The switching valve 112 a switches the connection between the discharge port of the compressor 18 and the heat exchange device 100 and the connection between the discharge port of the compressor 18 and the air discharge port 41. When exhausting the gas-liquid separation container 14, the switching valve 112 a is switched to the air discharge port 41 side to operate the compressor 18. Thus, by providing the switching valve 112a at the discharge port of the compressor 18, the compressor 18 can be used as a vacuum pump function.

  As described above, according to the refrigerant recovery apparatus 11b according to the present embodiment, the compressor 18 can be used as a vacuum pump for exhausting the gas-liquid separation container 14, so that the cost can be reduced and the refrigerant recovery apparatus 11b. Can be realized.

Embodiment 4 FIG.
FIG. 7 is a diagram illustrating a refrigerant recovery method according to the fourth embodiment. In the present embodiment, a refrigerant recovery method will be described in which the refrigerant recovery apparatus 11 (11a, 11b) that extracts refrigerant from a refrigeration air conditioner or the like that uses a flammable refrigerant in the atmosphere is operated in a low humidity environment. In FIG. 7, the refrigerant recovery apparatus 11 is accommodated in a refrigerant recovery apparatus installation room 52 that is a closed space, the room is dehumidified by the air conditioner 51, and the room is in a low humidity environment.

  It is known that LFL (Low-Flammable-Level: lower combustion concentration) of R-32, which is a slightly flammable refrigerant, burns at a relatively high concentration of 14.4 vol% and LFL of 1234yf is 6.5 vol%. . Therefore, in the unlikely event that a refrigerant leaks from the refrigerant recovery device 11 or the like, a combustible space exists only in the vicinity of the leakage place, and the leaked refrigerant diffuses at a certain distance from the leakage place, and the LFL It is difficult to think that the concentration will increase.

  Therefore, as described above, if the space having the flammable concentration is maintained in a low humidity environment, it is possible to reduce the worsening of an unexpected situation. At this time, the humidity value to be managed is different for each combustible gas refrigerant, and is preferably determined based on the data shown in the first embodiment.

  As described above, the level of humidity to be controlled is determined based on the combustible gas refrigerant to be handled and the assumed danger source, but is determined based on the result obtained by the method shown in the first embodiment. Thus, the performance of the dehumidifying device is not excessive. Therefore, according to the refrigerant recovery apparatus and the refrigerant recovery method described in the first to fourth embodiments, waste of the dehumidifying device is reduced, and cost reduction can be realized.

  Further, when the refrigerant recovery apparatus 11 is used in a closed space such as the refrigerant recovery apparatus installation room 52, a danger such as suffocation is assumed if the exhaust of the refrigerating machine oil is an inert gas such as nitrogen or argon. However, according to the refrigerant recovery apparatus and the refrigerant recovery method described in the first to fourth embodiments described above, the refrigerant recovery apparatus can be suitably used because it has a mechanism for discharging the refrigeration oil with dry air.

  Further, the refrigerant recovery apparatus and the refrigerant recovery method described in the first to fourth embodiments are not limited to the above-described refrigerating machine oil and combustible refrigerant, and may be oil or refrigerant other than the above-described refrigerating machine oil and combustible refrigerant. Applicable. Furthermore, even if the refrigerant is not a flammable refrigerant, where there is a risk of flammability due to dust or oil, the risk is reduced by the refrigerant recovery device and the refrigerant recovery method described in the first to fourth embodiments. Can be reduced.

  As mentioned above, although Embodiment 1-4 was demonstrated, you may implement combining 2 or more among these embodiments. Alternatively, one of these embodiments may be partially implemented. Alternatively, two or more of these embodiments may be partially combined.

  Further, the refrigerant recovery apparatus and the refrigerant recovery method described in the first to fourth embodiments described above are not limited to the refrigerant recovery apparatus and the refrigerant recovery method described in the embodiment described above and illustrated in the drawings. . For example, two series of gas-liquid separation containers are provided to provide a refrigerant recovery apparatus that realizes continuous refrigerant recovery work, or when a refrigerant recovery apparatus is installed in a low humidity space, a dehumidification device is used, and refrigerant recovery Various changes can be made as necessary without departing from the spirit of the present invention, such as making the entire work and related space a low humidity environment.

  11, 11a, 11b Refrigerant recovery device, 12 Refrigerant recovery cylinder, 13 Suction port, 14 Gas-liquid separation container, 15 Dehumidification device integrated valve, 16 Refrigerator oil discharge port, 17 Vacuum pump, 18 Compressor, 19 Oil separator, 20 R -32 cylinder, 21 autoclave, 22 regulator, 23 hot plate, 24 refrigerator oil container, 25 ignition source, 26 nebulizer, 31 air compressor, 32 condensate drain, 41 air outlet, 51 air conditioner, 52 refrigerant recovery device Installation room, 61 Refrigerant return pipe, 90 Refrigerant recovery device for comparison, 100 Heat exchange device, 111 Refrigerant storage container, 112, 112a Switching valve.

Claims (8)

A gas-liquid separator that is supplied with a mixture of refrigerant and refrigerating machine oil and separates the refrigerant from the mixture by negative pressure;
A compressor that is connected to the gas-liquid separator, generates a negative pressure in the gas-liquid separator, and discharges, collects, and compresses the refrigerant separated in the gas-liquid separator from the gas-liquid separator. And a heat exchange device that cools and liquefies the refrigerant compressed by the compressor, and a refrigerant discharge unit,
Refrigeration oil that is connected to the gas-liquid separator and is refrigerating machine oil that stays in the gas-liquid separator and in which at least a part of the refrigerant is separated, is provided so as to be discharged out of the gas-liquid separator. A machine oil discharge section;
Connected to the gas-liquid separator, feeds dry air having a humidity of 5 g / kg or less into the gas-liquid separator, and supplies the refrigerating machine oil in a state where at least a part of the refrigerant is separated through the refrigerating machine oil discharge part. A refrigerant recovery apparatus, comprising: a dry air supply unit that is discharged to the outside of the separator. The dry air supply unit
The refrigerant recovery apparatus according to claim 1, further comprising a dehumidifying device for dehumidifying gas, dehumidifying surrounding air by the dehumidifying device, and sending the dehumidified surrounding air as the dry air to the gas-liquid separator. . The dry air supply unit
2. The dry air is generated by sucking ambient air, condensing and separating moisture in the sucked ambient air, and feeding the generated dry air to the gas-liquid separator. Refrigerant recovery device. The refrigerant recovery device further includes:
The refrigerant recovery apparatus according to any one of claims 1 to 3, further comprising an air discharge unit that discharges the dry air sent to the gas-liquid separator from the gas-liquid separator.   The refrigerant recovery apparatus according to claim 1, wherein the refrigerant exhibits flammability in the atmosphere.   The refrigerant recovery apparatus according to claim 5, wherein the refrigerant is a mixture containing at least one of difluoromethane and tetrafluoropropene, difluoromethane, or tetrafluoropropene.   The refrigerant recovery method according to claim 1, wherein the refrigerant recovery apparatus is operated in a low humidity environment. In a refrigerant recovery method for processing a mixed liquid of refrigerant and refrigeration oil,
Operating the compressor, storing the mixed liquid in a gas-liquid separator, separating at least a part of the refrigerant from the mixed liquid stored in the gas-liquid separator by negative pressure, and separating the separated refrigerant A refrigerant discharge step of discharging and collecting from the gas-liquid separator, compressing and compressing, operating the heat exchange device to cool and liquefy the refrigerant compressed by the compressor;
A state in which dry air having a humidity of 5 g / kg or less is fed into the gas-liquid separator, and at least a part of the refrigerant is separated from the refrigerating machine oil stored in the gas-liquid separator by the pressure of the fed dry air And a refrigerating machine oil discharging step for discharging the refrigerating machine oil from the gas-liquid separator.

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