JP7334455B2 - Refrigerant recovery device - Google Patents

Description

The present invention relates to a refrigerant recovery device.

Refrigerant recovery devices are known in which the refrigerant in the refrigeration and air conditioning cycle is recovered in the outdoor unit by pump-down operation, and then the refrigerant remaining in the indoor unit and connecting pipes is recovered using a vacuum pump (see, for example, Patent Documents 1).

JP 2004-116885 A

However, in the refrigerant recovery device as disclosed in Patent Document 1, an electric vacuum pump is used to recover the refrigerant. Therefore, the structural portion through which the refrigerant to be collected passes includes a portion that requires an electrical drive, a portion that rubs against metal, and the like. Because of this, sparks can occur in atmospheres where combustible refrigerants are present, especially when combustible refrigerants are recovered.

The present invention has been made to solve such problems. It is an object of the present invention to provide a refrigerant recovery device that is capable of efficiently recovering the refrigerant without a portion requiring electrical driving or a portion where metals rub against each other in the structural portion through which the refrigerant to be recovered passes.

A refrigerant recovery device according to the present invention is a refrigerant recovery device for recovering a refrigerant from a refrigeration cycle device having a refrigerant pipe in which a refrigerant is enclosed, comprising: a refrigerant recovery connection pipe connected to the refrigerant pipe; a refrigerant recovery container connected to the refrigerant recovery connection pipe; an adsorbent provided in the refrigerant recovery container and capable of adsorbing the refrigerant; cooling means for cooling the refrigerant recovery container; a refrigerant diluting means for adding an inert gas to the refrigerant passing through the pipe to dilute the refrigerant, the refrigerant diluting means comprising a mixing pipe for mixing the refrigerant and the inert gas, The flow path in the mixing tube is curved by a plurality of staggered walls on the inner surface of the mixing tube.

Advantageous Effects of Invention According to the refrigerant recovery apparatus of the present invention, there is no portion requiring electrical driving in the structural portion through which the refrigerant to be recovered passes and no portion where metals rub against each other, and the refrigerant can be efficiently recovered.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram schematically showing the overall configuration of a refrigerant recovery device according to Embodiment 1 of the present invention; BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view schematically showing the configuration of a refrigerant recovery device according to Embodiment 1 of the present invention; FIG. 2 is a flow diagram showing an example of a refrigerant recovery method using the refrigerant recovery device according to Embodiment 1 of the present invention; FIG. 4 is a cross-sectional view schematically showing another example of the configuration of the refrigerant recovery device according to Embodiment 1 of the present invention; FIG. 2 is a diagram schematically showing the overall configuration of a refrigerant recovery device according to Embodiment 2 of the present invention; FIG. 6 is a cross-sectional view schematically showing the configuration of a mixing tube included in a refrigerant recovery device according to Embodiment 2 of the present invention; FIG. 5 is a flow diagram showing an example of a refrigerant recovery method using a refrigerant recovery device according to Embodiment 2 of the present invention;

Embodiments for carrying out the present invention will be described with reference to the accompanying drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals, and overlapping descriptions are appropriately simplified or omitted. The present invention is not limited to the following embodiments, and can be modified in various ways without departing from the scope of the present invention.

Embodiment 1.
Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 4. FIG. FIG. 1 is a diagram schematically showing the overall configuration of a refrigerant recovery device. FIG. 2 is a cross-sectional view schematically showing the configuration of the refrigerant recovery device. FIG. 3 is a flowchart showing an example of refrigerant recovery operation by the refrigerant recovery device. FIG. 4 is a cross-sectional view schematically showing another example of the configuration of the refrigerant recovery device.

A refrigerant recovery device 20 according to this embodiment recovers refrigerant from the refrigeration cycle device 10 shown in FIG. First, the configuration of the refrigeration cycle device 10 from which refrigerant is recovered by the refrigerant recovery device 20 will be described. The refrigerating cycle device 10 is specifically mounted in, for example, air conditioners, water heaters, showcases, refrigerators, and the like. A refrigeration cycle apparatus 10 according to this embodiment includes a refrigerant circuit shown in FIG. As shown in the figure, the refrigerant circuit comprises a compressor 13, a condenser 11, an expansion valve 15, and an evaporator 12, which are cyclically connected in this order by a refrigerant pipe 16. FIG.

The refrigerant circuit is filled with refrigerant. The refrigerant with which the refrigerant circuit is filled is a hydrocarbon refrigerant and is combustible. Specific examples of refrigerants include one or more refrigerants selected from propane (C3H8: R290), propylene (C3H6: R1270), normal butane (C4H10: R600), and isobutane (C4H6: R600a) (mixed ) refrigerant can be used. Hereinafter, the hydrocarbon refrigerant may be simply referred to as refrigerant.

The compressor 13 is a device that compresses refrigerant to increase the pressure and temperature of the refrigerant. Compressed refrigerant is discharged from the compressor 13 . The condenser 11 exchanges heat between the refrigerant discharged from the compressor 13 and the surrounding air or the like, and causes the refrigerant to radiate heat and condense. The expansion valve 15 expands the refrigerant condensed by the condenser 11 and reduces the pressure of the refrigerant. The expansion valve 15 is, for example, a linear electronic expansion valve (LEV). The evaporator 12 exchanges heat between the refrigerant depressurized by the expansion valve 15 and the surrounding air or the like, causing the refrigerant to absorb heat and evaporate.

A refrigerating cycle is realized by circulating the refrigerant through the refrigerant circuit configured as described above, and the refrigerating cycle functions as a heat pump that transfers heat between the evaporator 12 side and the condenser 11 side. In addition, in the configuration example shown in FIG. 1 , the compressor 13 is connected to the refrigerant pipe 16 via the four-way valve 14 . By switching the four-way valve 14, the circulation direction of the refrigerant in the refrigeration cycle can be reversed. When the circulation direction of the refrigerant is reversed, the functions of the evaporator 12 and the condenser 11 are reversed. Therefore, by switching the four-way valve 14, the direction of heat transfer between the evaporator 12 side and the condenser 11 side can be switched.

In this manner, the refrigerant is sealed inside the refrigerant pipe 16 of the refrigeration cycle device 10 . The refrigerant recovery device 20 of this embodiment recovers the refrigerant enclosed in the refrigerant circuit including the refrigerant pipe 16 of the refrigeration cycle device 10 .

The refrigerant recovery device 20 includes a refrigerant recovery connection pipe 22 and a refrigerant recovery container 30 . During refrigerant recovery by the refrigerant recovery device 20 , the refrigerant recovery connection pipe 22 is connected to the refrigerant pipe 16 of the refrigeration cycle device 10 . In the configuration example described here, a branch portion 21 is provided in the refrigerant pipe 16 between the condenser 11 and the expansion valve 15 of the refrigeration cycle device 10 . The branch part 21 is, for example, a three-way valve. By connecting one end of the refrigerant recovery connection pipe 22 to the branch portion 21 , the refrigerant pipe 16 and one end of the refrigerant recovery connection pipe 22 are connected via the branch portion 21 . A refrigerant recovery container 30 is connected to the other end of the refrigerant recovery connection pipe 22 .

Next, an example of the configuration of the refrigerant recovery container 30 will be described with reference to FIG. The refrigerant recovery container 30 has a recovery container main body 31 . The collection container main body 31 is a hollow container having, for example, a cylindrical shape. Hereinafter, the inside of the recovery container main body 31 may be referred to as the inside of the refrigerant recovery container 30 .

A container main body inlet 32 and a container main body outlet 33 are formed in the collection container main body 31 . The container main body inlet 32 and the container main body outlet 33 are openings communicating with the inside of the collection container main body 31 . The container main body inlet 32 is arranged on one side of the collection container main body 31 . The other end of the refrigerant recovery connection pipe 22 is connected to the container main body inlet 32 . The container body outlet 33 is arranged on the other side of the collection container body 31 .

The inside of the collection container main body 31 is filled with an adsorbent 34 . The adsorbent 34 can adsorb the refrigerant filled in the refrigeration cycle device 10 . The adsorbent 34 is made of a porous material in which many pores are formed. The individual pores of the adsorbent 34 are assumed to be larger than the molecular size of the refrigerant to be adsorbed. For example, the size of each pore of adsorbent 34 may be 4 Å or greater. Zeolite, activated carbon, alumina, or the like, for example, can be used as such an adsorbent 34 .

One end of an air release pipe 35 is connected to the container main body outlet 33 . The atmosphere release pipe 35 is a hollow tubular member. The other end of the air release tube 35 is an open port 36 . The inside of the collection container main body 31 is open to the outside through a container main body outlet 33 , an atmosphere release pipe 35 and an open port 36 . As described above, the refrigerant recovery container 30 includes the atmosphere release pipe 35 that communicates the inside and the outside of the recovery container main body 31 .

The refrigerant recovery device 20 has a cooling device 37 . The cooling device 37 is cooling means for cooling the refrigerant recovery container 30 . In the configuration example described here, the cooling device 37 includes a metal tube wound around the collection container main body 31 . Liquid nitrogen supplied from a supply source (not shown) flows through the metal pipe. The collection container main body 31 is cooled by the liquid nitrogen flowing inside the metal pipe.

A refrigerant recovery valve 23 is provided at an intermediate portion of the refrigerant recovery connection pipe 22 . The refrigerant recovery valve 23 is closed before the connection of the refrigerant recovery connection pipe 22 to the refrigerant pipe 16 is completed. By opening the refrigerant recovery valve 23 after the connection of the refrigerant recovery connection pipe 22 to the refrigerant pipe 16 is completed, recovery of the refrigerant to the refrigerant recovery container 30 is started. Hereinafter, the refrigerant of the refrigeration cycle device 10 to be recovered by the refrigerant recovery device 20 may be referred to as "recovered refrigerant".

The recovered refrigerant introduced into the refrigerant recovery container 30 from the refrigerant pipe 16 through the branch portion 21 and the refrigerant recovery connection pipe 22 flows into the recovery container main body 31 from the container main body inlet 32 . The recovered refrigerant that has flowed into the recovery container main body 31 is adsorbed by the adsorbent 34 inside the recovery container main body 31 . At this time, the collection container main body 31 is cooled by the cooling device 37 . The recovered refrigerant that has flowed into the recovery container main body 31 is cooled by the cooling device 37 to reduce its volume and pressure. Therefore, it is possible to suppress the re-release of the recovered refrigerant adsorbed by the adsorbent 34 and improve the adsorption efficiency.

In addition, since the pressure inside the recovery container main body 31 can be maintained lower than the pressure on the refrigerant circuit side of the refrigeration cycle device 10, the refrigerant in the refrigeration cycle device 10 is smoothly and continuously introduced into the refrigerant recovery device 20, It is possible to improve the refrigerant recovery rate. As described above, it is possible to shorten the time required to recover the refrigerant and improve the efficiency of the refrigerant recovery operation.

At this time, the cooling device 37 preferably cools the refrigerant recovery container 30 to a temperature below the boiling point of the refrigerant. Specifically, for example, when the refrigerant is R290, the cooling device 37 should cool to −42° C. or below. By doing so, the recovered refrigerant that has flowed into the recovery container main body 31 can be liquefied, and the volume and pressure of the recovered refrigerant in the recovery container main body 31 can be greatly reduced. Therefore, it is possible to further promote refrigerant recovery by the refrigerant recovery device 20 and further improve the efficiency of the refrigerant recovery operation.

As described above, the inside of the collection container main body 31 communicates with the outside through the atmosphere release pipe 35 . A portion of the recovered refrigerant introduced into the recovery container main body 31 but not adsorbed by the adsorbent 34 is released to the atmosphere from the open port 36 through the atmosphere release pipe 35 .

Next, an example of a refrigerant recovery method using the refrigerant recovery device 20 according to this embodiment configured as described above will be described with reference to the flowchart of FIG. First, in step S<b>1 , the refrigerant recovery container 30 is connected to the refrigerant pipe 16 of the refrigeration cycle device 10 via the refrigerant recovery connection pipe 22 . At this time, the refrigerant recovery valve 23 is closed.

In subsequent step S2, cooling of the refrigerant recovery container 30 by the cooling device 37 is started. As described above, the cooling device 37 preferably cools the refrigerant recovery container 30 to the boiling point of the recovered refrigerant or lower. Cooling of the refrigerant recovery container 30 by the cooling device 37 is continued until the process of step S4 is completed and the refrigerant recovery is completed. After step S2, the process proceeds to step S3.

In step S<b>3 , the refrigerant recovery valve 23 is opened to introduce the recovered refrigerant into the refrigerant recovery container 30 . In subsequent step S<b>4 , the recovered refrigerant introduced into the refrigerant recovery container 30 flows into the recovery container main body 31 . The recovered refrigerant that has flowed into the recovery container main body 31 is cooled by the cooling device 37 and adsorbed by the adsorbent 34 in the recovery container main body 31 . Part of the recovered refrigerant that has flowed into the recovery container main body 31 and has not been adsorbed by the adsorbent 34 is released into the atmosphere from the open port 36 through the atmosphere release pipe 35 . When the processing of step S4 is completed, the series of refrigerant recovery processing ends.

Next, another example of the refrigerant recovery container 30 will be described with reference to FIG. In the configuration example shown in FIG. 4 , a tubular mesh 38 is provided inside the recovery container main body 31 of the refrigerant recovery container 30 . The inner wall surface of the collection container main body 31 and the mesh 38 are arranged so that a constant gap is generated. The inside of the mesh 38 is filled with bead-like adsorbents 34 . Also, in this example, dry ice is used as the cooling device 37 .

In another example using the refrigerant recovery container 30 configured as described above, the same effects as in the case of using the refrigerant recovery container 30 of the configuration example shown in FIG. 2 can be obtained. Furthermore, since a gap can be formed between the adsorbent 34 and the inner wall surface of the recovery container main body 31, the recovered refrigerant that has flowed into the recovery container main body 31 can spread over a wide range of the surface of the adsorbent 34 through this gap. can improve adsorption efficiency. In addition, by using the bead-shaped adsorbent 34, the surface area of the adsorbent 34 can be increased and the contact area between the collected refrigerant and the adsorbent 34 can be increased, so an improvement in adsorption efficiency can be expected. Furthermore, by using dry ice for the cooling device 37, the configuration of the cooling device 37 can be simplified.

The refrigerant recovery device 20 configured as described above introduces the recovered refrigerant into the refrigerant recovery container 30 in which the adsorbent 34 is provided, and causes the adsorbent 34 to adsorb the refrigerant. recover the refrigerant from As a result, the refrigerant can be recovered without a portion requiring electrical driving or a portion where metals rub against each other in the structural portion through which the collected refrigerant passes. At this time, by cooling the refrigerant recovery container 30 with the cooling device 37, the recovered refrigerant adsorbed by the adsorbent 34 is suppressed from being released again, and the pressure inside the recovery container main body 31 is kept low. It is possible to smoothly and continuously introduce the refrigerant of the refrigeration cycle device 10 into the refrigerant recovery device 20, thereby improving the refrigerant recovery rate and the efficiency of the refrigerant recovery work.

Embodiment 2.
Embodiment 2 of the present invention will be described with reference to FIGS. 5 to 7. FIG. FIG. 5 is a diagram schematically showing the overall configuration of the refrigerant recovery device. FIG. 6 is a cross-sectional view schematically showing the configuration of a mixing tube provided in the refrigerant recovery device. FIG. 7 is a flowchart showing an example of a refrigerant recovery method using a refrigerant recovery device.

Embodiment 2 described here is configured such that, in the configuration of Embodiment 1 described above, inert gas is added to the refrigerant to be collected to dilute the refrigerant while it is being collected. The refrigerant recovery apparatus according to the second embodiment will be described below, focusing on differences from the first embodiment. The configuration whose description is omitted is basically the same as that of the first embodiment.

A refrigerant recovery device 20 according to this embodiment includes an inert gas cylinder 40 and a gas mixing pipe 42, as shown in FIG. One end of the refrigerant recovery connection pipe 22 is connected to the refrigerant pipe 16 of the refrigeration cycle device 10 via the branch portion 21 as in the first embodiment. The other end of the refrigerant recovery connection pipe 22 is branched into two. One of the branches on the other end side of the refrigerant recovery connection pipe 22 is connected to the refrigerant recovery container 30 via the gas mixing pipe 42 .

The other branch on the other end side of the refrigerant recovery connecting pipe 22 is connected to an inert gas cylinder 40 . The inert gas cylinder 40 is a supply source of inert gas. The inert gas cylinder 40 is filled with inert gas. The inert gas filled in the inert gas cylinder 40 is specifically, for example, a rare gas such as argon, nitrogen, or the like.

A flow control valve 41 is provided between the branched portion of the refrigerant recovery connection pipe 22 and the branched portion 21 . A flow control valve 41 is also provided between the branch point of the refrigerant recovery connection pipe 22 and the inert gas cylinder 40 . With these flow control valves 41 , the flow rate of the recovered refrigerant flowing into the refrigerant recovery device 20 from the branch portion 21 and the flow rate of the inert gas supplied from the inert gas cylinder 40 can be adjusted.

The recovered refrigerant flowing into the refrigerant recovery device 20 from the branch portion 21 and the inert gas supplied from the inert gas cylinder 40 join at the branch point of the refrigerant recovery connection pipe 22 . The combined collected refrigerant and inert gas pass through the gas mixing pipe 42 and flow into the refrigerant collection container 30 .

Next, an example of the configuration of the gas mixing pipe 42 will be described with reference to FIG. As shown in the figure, a plurality of walls 43 are provided on the inner surface of the gas mixing tube 42 . The plurality of wall portions 43 are arranged alternately, and the flow path in the gas mixing tube 42 is bent by the wall portions 43 . The recovered refrigerant and inert gas passing through the gas mixing pipe 42 are sufficiently mixed through such a curved flow path. Thus, the recovered refrigerant flowing into the refrigerant recovery container 30 through the gas mixing pipe 42 is mixed and diluted with the inert gas to a uniform concentration.

The inert gas cylinder 40 and the gas mixing pipe 42 configured as described above constitute refrigerant diluting means for diluting the refrigerant by adding an inert gas to the refrigerant passing through the refrigerant recovery connecting pipe 22 . In this embodiment, the refrigerant diluting means has a gas mixing pipe 42 for mixing the refrigerant and the inert gas.

In the configuration example shown in FIG. The degree of dilution of recovered refrigerant with inert gas can be varied. Therefore, it is preferable to adjust the flow rate of the recovered refrigerant and the flow rate of the inert gas so that the concentration of the recovered refrigerant after mixing and dilution is less than the LFL concentration (LFL=Lower Flammable Limit) of the recovered refrigerant. By doing so, even if the gas containing the recovered refrigerant leaks during the refrigerant recovery operation, it is possible to suppress the immediate formation of a region outside where the refrigerant has a concentration equal to or higher than the LFL concentration. A pressure-controlled gas mixer may be used instead of the flow control valve 41 .

Next, an example of a refrigerant recovery method using the refrigerant recovery apparatus 20 according to this embodiment configured as described above will be described with reference to the flowchart of FIG. First, in step S<b>11 , the refrigerant recovery container 30 is connected to the refrigerant pipe 16 of the refrigeration cycle device 10 via the refrigerant recovery connection pipe 22 . Also, the inert gas cylinder 40 is connected to the refrigerant recovery container 30 via the refrigerant recovery connection pipe 22 . At this time, the refrigerant recovery valve 23 is closed. After step S11, the process proceeds to step S12.

In step S12, the flow rate of the recovered refrigerant and the flow rate of the inert gas are adjusted by the respective flow control valves 41 so that the concentration of the recovered refrigerant after mixing and dilution is less than the LFL concentration of the recovered refrigerant. In subsequent step S13, cooling of the refrigerant recovery container 30 by the cooling device 37 is started. As described above, the cooling device 37 preferably cools the refrigerant recovery container 30 to the boiling point of the recovered refrigerant or lower. Cooling of the refrigerant recovery container 30 by the cooling device 37 is continued until the process of step S15 is completed and the refrigerant recovery is completed. After step S13, the process proceeds to step S14.

In step S<b>14 , the refrigerant recovery valve 23 is opened to introduce the mixed gas containing the recovered refrigerant into the refrigerant recovery container 30 . In subsequent step S<b>15 , the mixed gas introduced into the refrigerant recovery container 30 flows into the recovery container main body 31 . The mixed gas that has flowed into the recovery container body 31 is cooled by the cooling device 37 and adsorbed by the adsorbent 34 in the recovery container body 31 . A portion of the mixed gas that has flowed into the recovery container main body 31 and has not been adsorbed by the adsorbent 34 is released into the atmosphere from the open port 36 through the open air pipe 35 . When the processing of step S15 is completed, the series of refrigerant recovery processing ends.

The refrigerant recovery apparatus configured as described above can also achieve the same effects as those of the first embodiment. Furthermore, by collecting the refrigerant while mixing and diluting it with an inert gas, even if the gas containing the collected refrigerant leaks during the refrigerant recovery operation, it is possible to suppress the formation of a region with a high concentration of the refrigerant outside.

In the above description, propane (R290), propylene (R1270), normal butane (R600), and isobutane (R600a) are listed as refrigerants to be recovered. However, the refrigerant to be collected is not limited to these. Other examples include tetrafluoropropene (CF3CF=CH2:HFO-1234yf), difluoromethane (CH2F2:R32), ethane (R170), 1.1.1.2-tetrafluoroethane (C2H2F4:R134a), pentafluoroethane Refrigerants such as (C2HF5:R125) and 1,3,3,3-tetrafluoro-1-propene (CF3-CH=CHF:HFO-1234ze) may be recovered.

Also, the refrigerant to be recovered may be a toxic refrigerant such as carbon dioxide (CO2: R744), ammonia (NH3: R717), R1123, or the like. When using these toxic refrigerants, the gas that dilutes the recovered refrigerant may be air or oxygen.

REFERENCE SIGNS LIST 10 Refrigeration cycle device 11 Condenser 12 Evaporator 13 Compressor 14 Four-way valve 15 Expansion valve 16 Refrigerant pipe 20 Refrigerant recovery device 21 Branch 22 Refrigerant recovery connection pipe 23 Refrigerant recovery valve 30 Refrigerant recovery container 31 Recovery container body 32 Container Body inlet 33 Container body outlet 34 Adsorbent 35 Atmospheric open pipe 36 Open port 37 Cooling device 38 Mesh 40 Inert gas cylinder 41 Flow control valve 42 Gas mixing pipe 43 Wall

Claims (3)

A refrigerant recovery device for recovering the refrigerant from a refrigeration cycle device having a refrigerant pipe in which the refrigerant is enclosed,
a refrigerant recovery connection pipe connected to the refrigerant pipe;
a refrigerant recovery container connected to the refrigerant recovery connection pipe;
an adsorbent provided in the refrigerant recovery container and capable of adsorbing the refrigerant;
a cooling means for cooling the refrigerant recovery container;
a refrigerant diluting means for adding an inert gas to the refrigerant passing through the refrigerant recovery connection pipe to dilute the refrigerant ;
The refrigerant dilution means comprises a mixing tube for mixing the refrigerant and the inert gas,
The refrigerant recovery device, wherein the flow path in the mixing tube is bent by a plurality of wall portions provided alternately on the inner surface of the mixing tube. 2. The refrigerant recovery apparatus according to claim 1, wherein the cooling means cools the refrigerant recovery container to a boiling point of the refrigerant or lower. 3. The refrigerant recovery apparatus according to claim 1, wherein the refrigerant recovery container includes an open-air pipe that communicates the inside and the outside of the refrigerant recovery container.

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