WO2007105425A1

WO2007105425A1 - Method of recovering refrigerator oil

Info

Publication number: WO2007105425A1
Application number: PCT/JP2007/053061
Authority: WO
Inventors: Junichi Shimoda; Sadayuki Wada; Kazushi Yamaoka
Original assignee: Daikin Industries, Ltd.
Priority date: 2006-02-23
Filing date: 2007-02-20
Publication date: 2007-09-20
Also published as: CN101379351B; JP3956997B1; AU2007225990B2; EP1992893A1; CN101379351A; EP1992893A4; AU2007225990A1; JP2007225184A

Abstract

A method of recovering refrigerator oil has a first step and a second step that are performed in sequence. In the first step, the refrigerator oil is recovered from a gas side port (28) together with a part of refrigerant in that part of a refrigerant circuit (20) which communicates with the gas side port (28). The gas side port (28) is open to an interconnecting line (24) that is on the gas side of the position closed by a closing valve (26) installed at one end of a heat source side circuit (21). In the second step, the refrigerator oil is recovered from a liquid side port (27), with the gas side closing valve (26) closed, together with a part or the whole of the refrigerant in that part of the refrigerant circuit (20) which communicates with the liquid side port (27). The liquid side port (27) is open to an interconnecting line (23) that is on the liquid side of the position closed by a closing valve (25) installed at the other end of the heat source side circuit (21).

Description

Specification

Refrigerating machine oil recovery method

Technical field

[0001] The present invention relates to a refrigeration apparatus comprising a refrigerant circuit configured by connecting a heat source unit and a utilization unit by a gas side communication pipe and a liquid side connection pipe, from the gas side communication pipe and the liquid side connection pipe. The present invention relates to a method for recovering refrigerating machine oil for recovering refrigerating machine oil. Background art

Conventionally, regarding a refrigeration apparatus having a refrigerant circuit configured by connecting a heat source unit and a utilization unit through a communication pipe, a method for efficiently removing refrigeration oil in the communication pipe is known. It has been. This type of refrigerating machine oil recovery method is used, for example, when the connection pipe is used as it is when the heat source unit and the utilization unit are updated.

[0003] Specifically, Patent Document 1 discloses a residual oil recovery method as a recovery method of this type of refrigeration oil. In this residual oil recovery method, the refrigerant storage operation and the refrigerant charging operation are performed after the pump-down for collecting the refrigerant in the refrigerant circuit into the heat source circuit. In the refrigerant storage operation, one of the liquid side shutoff valve and the gas side shutoff valve is closed and the other is opened, and the collector is connected to the port of the closed shutoff valve so that the refrigerating machine oil is combined with the refrigerant in the refrigerant circuit. Recover. In the refrigerant charging operation, the closing valve that is closed by the refrigerant containing operation is opened while the opening valve that is opened is closed. Then, a recovery unit that stores the refrigerant recovered by the refrigerant storage operation is connected to the port of the closed closing valve via the refrigerant regenerator, and the refrigerant is discharged from the recovery unit and refrigerated by the refrigerant regenerator. Fill the refrigerant circuit with the refrigerant from which machine oil has been removed. In this residual oil recovery method, the refrigerant storage operation and the refrigerant charging operation are repeated as necessary.

Patent Document 1: Japanese Patent Laid-Open No. 2003-194437

Disclosure of the invention

Problems to be solved by the invention

[0004] By the way, in the conventional method for recovering refrigeration oil, it is necessary to perform not only the refrigerant storage operation but also the refrigerant charging operation in order to collect more refrigeration oil with connecting pipe power. That means Since the refrigerant charging operation was performed after the refrigerant storage operation and further refrigerant storage operation was required, at least three operations were required. Therefore, the operation of recovering the refrigeration oil has been very laborious.

[0005] The present invention has been made in view of the points to be applied, and an object of the present invention is to provide a communication piping force for a refrigeration apparatus including a refrigerant circuit in which a heat source unit and a utilization unit are connected by a communication piping. In the method of recovering refrigeration oil, the effort to recover refrigeration oil efficiently is reduced.

Means for solving the problem

[0006] In the first invention, the heat source side circuit (21) in the heat source unit (11) and the utilization side circuit (22) in the utilization unit (13) are connected to the gas side communication pipe (24) and the liquid side communication pipe. For the refrigeration apparatus (10) that performs the refrigeration cycle in the refrigerant circuit (20) connected by (23), the gas side communication pipe (24) and the liquid side communication pipe (23) are also used for the refrigerating machine oil. The method of collection is targeted. Then, this method includes the gas side port (28) opened to the gas side connection pipe (24) side of the closed position of the gas side shutoff valve (26) provided at one end of the heat source side circuit (21). In the refrigerant circuit (20), the first stage for collecting the refrigeration oil together with a part of the refrigerant communicating with the gas side port (28), and the gas side shut-off valve (26) being closed From the liquid side port (27) opened to the liquid side connecting pipe (23) side of the liquid side closing valve (25) provided at the other end of the heat source side circuit (21), the refrigerant circuit (20) Of these, the second step of collecting the refrigerating machine oil together with part or all of the refrigerant communicating with the liquid side port (27) is sequentially performed.

[0007] In a second aspect based on the first aspect, the first step is performed with the gas side closing valve (26) closed.

[0008] In a third invention according to the first or second invention, the first step and the second step are performed with the liquid side closing valve (25) opened.

[0009] In a fourth invention according to any one of the first to third powers, the third step of recovering the refrigerant of the heat source side circuit (21) is performed after the end of the second step.

[0010] A fifth invention is the refrigerant of the heat source side circuit (21) from the gas side port (28) while gradually opening the gas side shut-off valve (26) in the third step in the fourth invention. Recover.

[0011] In a sixth aspect based on the fourth aspect, in the third step, the heat source side circuit (21) The operation of recovering the refrigerant in the heat source side circuit (21) from the open heat source side port (9), and gradually opening the gas side stop valve (26) from the gas side port (28) to the heat source side circuit ( 21) Collect the refrigerant.

[0012] One action

In the first invention, the first step and the second step are performed in order. By the way, before the first step, it is normal that more liquid coolant is present in the use side circuit (22) and liquid side connection pipe (23) than in the gas side connection pipe (24). . In this state, when the refrigerant is sucked out in the first step, at least the gas side port (28) communicating with the gas side communication pipe (24), the use side circuit (22), and the liquid side communication pipe (23) is sucked. The refrigerant from the use side circuit (22) and the liquid side connection pipe (23) flows into the gas side connection pipe (24). Then, the refrigeration oil adhering to the gas side communication pipe (24) is peeled off by the flow of the refrigerant. The peeled refrigeration oil is recovered from the gas side port (28) together with the refrigerant.

[0013] At the end of the first step, refrigerant remains in the liquid side communication pipe (23), the use side circuit (22), and the gas side communication pipe (24) in the refrigerant circuit (20). become. In this state, when the refrigerant is sucked out from the liquid side port (27) communicating with at least the liquid side connecting pipe (23), the use side circuit (22), and the gas side connecting pipe (24) in the second step. The refrigerant from the gas side connecting pipe (24) flows into the liquid side connecting pipe (23). Then, the refrigerating machine oil attached to the liquid side connecting pipe (23) is peeled off by the flow of the refrigerant. The peeled refrigeration oil is collected from the liquid side port (27) together with the refrigerant. In the second step, since the gas side shut-off valve (26) is closed, the refrigerant or refrigeration oil does not flow into the gas side communication pipe (24) from the heat source side circuit (21).

[0014] In each of the connecting pipes (23, 24) in the first step and the second step, the energy loss is smaller when the near port (27, 28) force also sucks the refrigerant! / Becomes larger. Therefore, much of the refrigerant adhering to the gas side connecting pipe (24) is peeled off during the first step of sucking out the refrigerant from the gas side port (28), and the refrigerant adhering to the liquid side connecting pipe (23) is separated from the liquid side port. A large amount of the second step of sucking out the refrigerant from (27) is peeled off. In the first invention, the refrigerant is sucked out from the separate ports (27, 28) in the first step and the second step, so that a relatively large number of each of the connection pipes (27, 28) can be obtained. Refrigerating machine oil is peeled off. In the second invention, the refrigerant is also sucked out by the gas side port (28) force with the gas side closing valve (26) closed in the first step. Therefore, the refrigerant in the heat source side circuit (21) does not suck out the gas side port (28) force through the gas side closing valve (26).

[0016] In the first step of the third invention, the gas side port (28) includes not only the gas side communication pipe (24), the use side circuit (22), and the liquid side communication pipe (23). The heat source side circuit (21) communicates with the liquid side stop valve (25). In the first step, the refrigerant is sucked out from the gas side port (28) in this state. Therefore, in the first step, the refrigerant in the heat source side circuit (21) flows into the utilization unit (13) through the liquid side shut-off valve (25), so the first side with the liquid side shut-off valve (25) closed. Compared with the case where the process is performed, the amount of refrigerant going back and forth on the use unit (13) side between the gas side port (28) and the liquid side port (27) increases in the first step and the second step.

[0017] In the fourth invention, the refrigerant in the heat source side circuit (21) is recovered in the third step after the second step.

Therefore, the amount of refrigerant remaining in the heat source side circuit (21) after performing this method of recovering refrigeration oil is reduced.

[0018] In the fifth aspect, in the third step, the operation of recovering the refrigerant in the heat source side circuit (21) from the gas side port (28) while gradually opening the gas side closing valve (26) is performed. Here, before the start of the third step, the gas side communication pipe (24) side from which the refrigerant and the refrigeration oil were recovered in the first step and the second step is sandwiched between the gas side shut-off valve (26) and the heat source side circuit. There is a risk that the pressure will be lower than the (21) side! In this case, if the gas side closing valve (26) is suddenly opened, the refrigerant in the heat source side circuit (21) or the refrigerating machine oil flows into the gas side connection pipe (24). In the fifth aspect of the invention, the refrigerant and the refrigeration oil in the heat source side circuit (21) flow into the gas side communication pipe (24) by collecting the refrigerant while gradually opening the gas side stop valve (26). To suppress.

[0019] In the sixth invention, the refrigerant in the heat source side circuit (21) is recovered by the heat source side port (9) and the gas side port (28). Therefore, the amount of refrigerant remaining in the heat source side circuit (21) after performing this refrigerating machine oil recovery method is further reduced. Similarly to the fifth aspect of the invention, the operation of recovering the refrigerant in the heat source side circuit (21) from the gas side port (28) is performed by gradually opening the gas side shut-off valve (26) so that the heat source Refrigerating machine oil in the side circuit (21) is prevented from flowing into the gas side connecting pipe (24).

The invention's effect [0020] In the present invention, the gas side port (28) force is sucked out in the first step, and the refrigerating machine oil adhering mainly to the gas side connecting pipe (24) is peeled off, and the liquid side port (27) in the second step. The refrigerant is sucked out from the refrigeration oil to remove mainly the refrigeration oil adhering to the liquid side communication pipe (23). In other words, when all the refrigerant is sucked out from any port (27,28), the refrigeration oil in the connecting pipe (23,24) on the opposite side of the sucking out port (27,28) is hard to be recovered! / However, since the first step of sucking the refrigerant from the gas side port (28) and the second step of sucking the refrigerant from the liquid side port (27) are performed, a relatively large amount of refrigeration is performed from the respective connecting pipes (23, 24). Machine oil can be recovered. In addition, the conventional method in which the refrigerant filling operation is performed in order to increase the recovered amount of refrigerating machine oil requires at least three operations, but in the method of the present invention, the first step and the second step are performed twice. In this operation, the refrigeration oil in the gas side communication pipe (24) and liquid side communication pipe (23) can be efficiently recovered. Since the amount of refrigerant to be recovered is reduced by the amount of refrigerant not charged, the time required for recovery of the refrigerant can be shortened. Therefore, according to the present invention, it is possible to reduce the labor of collecting the refrigerating machine oil efficiently.

In the second invention, in the first step, the refrigerant in the heat source side circuit (21) passes through the gas side closing valve (26) by closing the gas side closing valve (26). The gas side port (28) is not sucked out. Therefore, compared with the case where the first step is performed with the gas side shutoff valve (26) open, the flow rate of the refrigerant in the gas side communication pipe (24) increases, so the force on the gas side communication pipe (24) also increases. The amount of refrigerating machine oil that is peeled off and recovered increases.

[0022] In the third invention, the first step is performed with the liquid side shut-off valve (25) opened, so that the gas side port (28) and the liquid side port are connected to the liquid side closing valve (25) over the first step and the second step. The amount of refrigerant going back and forth between the side ports (27) on the side of the utilization unit (13) is increased. That is, the total amount of refrigerant flowing through the gas side connecting pipe (24) and the liquid side connecting pipe (23) increases. Therefore, more refrigeration oil can be removed and recovered from the gas side communication pipe (24) and the liquid side communication pipe (23).

[0023] In addition, in the fourth invention, the refrigerant remaining in the heat source side circuit (21) after performing this method of recovering refrigeration oil by performing the third step of recovering the refrigerant in the heat source side circuit (21). The amount is reduced. Therefore, when the heat source unit (11) is updated, the trouble of collecting the refrigerant from the removed heat source unit (11) can be omitted or reduced. In addition, the cooling of the refrigerant circuit (20) When replacing the medium, the reliability of the refrigeration apparatus (10) can be improved.

[0024] In the fifth aspect of the invention, the operation of recovering the refrigerant in the heat source side circuit (21) from the gas side port (28) in the third step is performed while the gas side shut-off valve (26) is gradually opened. The refrigerant in the heat source side circuit (21) is prevented from flowing into the gas side communication pipe (24) from which the refrigerant and the refrigerant oil are recovered. Therefore, it is possible to avoid a state in which it is necessary to recover the refrigerant or the refrigerating machine oil from the gas side communication pipe (24) after the third step.

[0025] According to the sixth invention, the refrigerant of the heat source side circuit (21) is recovered from the heat source side port (9) and the gas side port (28). After the operation, the refrigerant remaining in the heat source side circuit (21) is further reduced. Therefore, when the heat source unit (11) is updated, the trouble of collecting the refrigerant from the removed heat source unit (11) can be omitted or further reduced. In addition, when the refrigerant in the refrigerant circuit (20) is replaced, the reliability of the refrigeration apparatus (10) can be further improved. Similarly to the fifth aspect of the invention, the operation of recovering the refrigerant in the heat source side circuit (21) from the gas side port (28) is performed while gradually opening the gas side shut-off valve (26). Gas side communication pipe after 3 steps (24) Force It is possible to avoid the situation where it is necessary to recover the refrigerant or the refrigerating machine oil.

Brief Description of Drawings

FIG. 1 is a schematic configuration diagram of a refrigeration apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram at the time of a first step of the refrigeration apparatus in the embodiment.

FIG. 3 is a schematic configuration diagram at the time of a second step of the refrigeration apparatus in the embodiment.

Explanation of symbols

9 Heat source side port

10 Refrigeration equipment

11 Outdoor unit (heat source unit)

13 Indoor unit (indoor unit)

20 Refrigerant circuit

21 Outdoor circuit (heat source side circuit)

22 Indoor circuit (use side circuit)

23 Liquid side connection piping 24 Gas side communication piping

25 Liquid side stop valve

26 Gas side shut-off valve

27 Liquid side service port (Liquid side port)

28 Gas side service port (gas side port)

BEST MODE FOR CARRYING OUT THE INVENTION

[0028] An embodiment of the present invention will be described. In the following, an air conditioner as a refrigeration apparatus to which a method for recovering refrigeration oil according to the present invention is applied will be described first, and then a method for recovering refrigeration oil according to the present invention will be described.

[0029] Configuration of refrigeration equipment

FIG. 1 is a schematic configuration diagram of a refrigeration apparatus (10) according to this embodiment. This refrigeration system (10

) Is an air conditioner including an outdoor unit (11) that is a heat source unit and an indoor unit (13) that is a utilization unit, and is configured to perform switching between a cooling operation and a heating operation. The number of indoor units (13) is not limited to one, and may be plural.

[0030] An outdoor circuit (21), which is a heat source side circuit, is provided in the outdoor unit (11). In the indoor unit (13), an indoor circuit (22) which is a use side circuit is provided. In this refrigeration system (10), a refrigerant circuit that performs a vapor compression refrigeration cycle by connecting an outdoor circuit (21) and an indoor circuit (22) with a liquid side connecting pipe (23) and a gas side connecting pipe (24). (20) is configured.

[0031] Outdoor unit

The outdoor circuit (21) of the outdoor unit (11) includes a compressor (30), a four-way selector valve (33), an outdoor heat exchange ^ (34), an expansion valve (36), a receiver (39) and an accumulator (35 ) Is provided. One end of the outdoor circuit (21) is provided with a liquid side shut-off valve (25) to which the liquid side communication pipe (23) is connected. The other end of the outdoor circuit (21) is provided with a gas side closing valve (26) to which a gas side communication pipe (24) is connected.

The liquid side shut-off valve (25) is provided with a liquid side service port (27). The liquid side service port (27) opens to the liquid side connecting pipe (23) side of the liquid side closing valve (25) in the closed position. On the other hand, the gas side stop valve (26) is provided with a gas side service port (28). The gas side service port (28) opens to the gas side connecting pipe (24) side of the closed position of the gas side closing valve (26). These ports (27, 28) are used when collecting refrigerant and refrigerating machine oil in the refrigerant circuit (20) or filling refrigerant into the refrigerant circuit (20), and during cooling operation and heating operation. It is closed.

[0033] The compressor (30) is configured as a hermetic and high-pressure dome type compressor. The discharge side of the compressor (30) is connected to the first port (P1) of the four-way switching valve (33) via the discharge pipe (40). The suction side of the compressor (30) is connected to the third port (P3) of the four-way switching valve (33) via the suction pipe (41).

[0034] The outdoor heat exchanger (34) is configured as a cross-fin type fin-and-tube heat exchanger. An outdoor fan (12) is provided in the vicinity of the outdoor heat exchanger (34). In the outdoor heat exchanger (34), heat is exchanged between the outdoor air sent by the outdoor fan (12) and the circulating refrigerant. One end of the outdoor heat exchanger (34) is connected to the fourth port (P4) of the four-way selector valve (33) via the connecting pipe (32). The other end of the outdoor heat exchanger (34) is connected to the liquid side shut-off valve (25) via the liquid pipe (42). The second port (P2) of the four-way selector valve (33) is connected to the gas side shutoff valve (26).

[0035] The connection pipe (32) is provided with a heat source side port (9) that opens to the connection pipe (32). The heat source side port (9) is used when recovering the refrigerant in the heat source side circuit (21) in the third step described later, and is closed during the cooling operation and the heating operation.

[0036] The liquid pipe (42) is provided with a receiver (39) and an expansion valve (36) in order of the outdoor heat exchange (34) side force. The receiver (39) is formed in a sealed container shape and can temporarily store the high-pressure refrigerant condensed in the outdoor heat exchanger (34). The expansion valve (36) is configured as an electronic expansion valve with variable opening.

[0037] The suction pipe (41) is provided with an accumulator (35). The accumulator (35) is formed in a closed container shape and is directed to the compressor (30) so that the compressor (30) does not suck the liquid refrigerant. It is comprised so that it may store.

[0038] The four-way selector valve (33) is in the first state in which the first port (P1) and the second port (P2) communicate with each other and the third port (P3) and the fourth port (P4) communicate with each other. (Indicated by the solid line in Fig. 1) and the first point Port (PI) and the fourth port (P4) are in communication with each other, and the second port (P2) and the third port (P3) are in communication with each other. Switching is possible.

[0039] 《Indoor unit》

The indoor circuit (22) of the indoor unit (13) is provided with an indoor heat exchanger (37). At one end of the indoor circuit (22), a liquid side flare joint (38) to which the liquid side communication pipe (23) is connected is provided. The other end of the indoor circuit (22) is provided with a gas side flare joint (39) to which the gas side communication pipe (24) is connected.

[0040] The indoor heat exchange (37) is configured as a cross-fin fin 'and' tube heat exchange. An indoor fan (14) is provided in the vicinity of the indoor heat exchanger (37). In this indoor heat exchanger (37), heat is exchanged between the indoor air sent by the indoor fan (14) and the circulating refrigerant.

[0041] Operation of refrigeration equipment

Next, the operation of the refrigeration apparatus (10) will be described. The refrigeration apparatus (10) can perform a cooling operation and a heating operation by switching the four-way switching valve (33).

[0042] Cooling operation>

In the cooling operation, the four-way selector valve (33) is set to the second state. When the compressor (30) is operated in this state, a vapor compression refrigeration cycle in which the outdoor heat exchanger (34) serves as a condenser and the indoor heat exchanger (37) serves as an evaporator in the refrigerant circuit (20). Done. In the cooling operation, the opening degree of the expansion valve (36) is appropriately adjusted.

[0043] Specifically, the refrigerant discharged by the compressor (30) is condensed by exchanging heat with outdoor air in the outdoor heat exchanger (34). The refrigerant condensed in the outdoor heat exchange (34) is depressurized when passing through the expansion valve (36), and then evaporates by exchanging heat with the indoor air in the indoor heat exchange (37). The refrigerant evaporated in the indoor heat exchanger (37) is sucked into the compressor (30) and compressed.

[0044] <Heating operation>

In the heating operation, the four-way selector valve (33) is set to the first state. When the compressor (30) is operated in this state, a vapor compression refrigeration cycle in which the outdoor heat exchanger (34) serves as an evaporator and the indoor heat exchanger (37) serves as a condenser in the refrigerant circuit (20) is performed. Is called. Even in the heating operation, the opening degree of the expansion valve (36) is appropriately adjusted. [0045] Specifically, the refrigerant discharged from the compressor (30) is condensed by exchanging heat with indoor air in the indoor heat exchanger (37). The refrigerant condensed in the indoor heat exchange (37) is depressurized when passing through the expansion valve (36), and then evaporates by exchanging heat with the outdoor air in the outdoor heat exchange (34). The refrigerant evaporated in the outdoor heat exchanger (34) is sucked into the compressor (30) and compressed.

[0046] Refrigerating machine oil recovery method

Next, a method for recovering refrigeration oil from the gas side communication pipe (24) and the liquid side communication pipe (23) of the refrigeration apparatus (10) will be described. This refrigerating machine oil recovery method can be used when the outdoor unit (11) and the indoor unit (13) are replaced with new units when the gas side connecting pipe (24) and liquid side connecting pipe (23) are used as they are. Used when replacing refrigerant in refrigerant circuit (20). In this refrigerating machine oil recovery method, the first, second, and third steps are sequentially performed. Each step will be described below.

[0047] First step>

In the first step, the gas side closing valve (26) is closed and the liquid side closing valve (25) is opened. Since the four-way switching valve (33) and the expansion valve (36) of the outdoor circuit (21) are not particularly adjusted, they are in a state when the operation of the refrigeration apparatus (10) is finished. In this state, the gas-side service port (28) communicates with the gas-side connecting pipe (24), the indoor circuit (22), and the liquid-side connecting pipe (23), and further via the liquid-side shutoff valve (25). It also communicates with the outdoor circuit (21).

[0048] Then, as shown in FIG. 2, the refrigerant recovery unit (45) is connected to the gas side service port (28). The refrigerant recovery unit (45) is a device including a vacuum pump and a recovery container. The refrigerant recovery unit (45) is configured so that the refrigerant sucked by the vacuum pump can be stored in the recovery container. When the refrigerant recovery unit (45) is connected to the gas side service port (28), the vacuum pump of the refrigerant recovery unit (45) is operated.

[0049] Prior to operation of the vacuum pump, the indoor circuit (22) and the liquid side communication pipe are connected to the gas side connection pipe (24).

Normally, (23) there are many liquid refrigerants. When the vacuum pump is operated in this state, the refrigerant in the refrigerant circuit (20) communicating with the gas service port (28) moves toward the gas service port (28). As the vacuum pump is operated, the refrigerant in the indoor circuit (22) and the liquid side communication pipe (23) flows into the gas side communication pipe (24) as it is or flows into the gas-liquid two-phase state. To do. And attached to the gas side communication pipe (24) The refrigerating machine oil that arrives dissolves in the liquid refrigerant (gas-liquid two-phase refrigerant) or is pushed away by the flow of the refrigerant. The removed refrigeration oil is recovered from the gas service port (28) together with the refrigerant. The operation of the vacuum pump in the first step is performed for a predetermined time (for example, 1 minute). The operating time of the vacuum pump is set so that all of the refrigerant in the refrigerant circuit (20) communicating with the gas side service port (28) is not collected. At the end of the first step, the refrigerant remains in the liquid side communication pipe (23), the indoor circuit (22), and the gas side communication pipe (24) in the refrigerant circuit (20).

[0050] Second step>

In the second step, as in the first step, the gas side shutoff valve (26) is closed and the liquid side shutoff valve (25) is opened. In this state, the liquid side service port (27) communicates with both sides of the closing position of the closing valve (25). That is, the liquid side service port (27) communicates with the liquid side communication pipe (23), the indoor circuit (22), and the gas side communication pipe (24), and further communicates with the outdoor circuit (21). Then, as shown in Fig. 3, the refrigerant recovery unit (45) removed from the gas side service port (28) is connected to the liquid side service port (27), and the vacuum pump of the refrigerant recovery unit (45) is operated. Let

[0051] When the vacuum pump is operated, the refrigerant in the portion of the refrigerant circuit (20) communicating with the liquid side service port (27) moves toward the liquid side service port (27). With the operation of the vacuum pump, the liquid refrigerant (gas-liquid two-phase refrigerant) in the indoor circuit (22) and the gas side communication pipe (24) flows into the liquid side communication pipe (23). Then, it dissolves in the refrigeration hydraulic fluid refrigerant (gas-liquid two-phase refrigerant) adhering to the liquid side connecting pipe (23) or is peeled off by being pushed away by the refrigerant flow. The removed refrigeration oil is recovered from the liquid side service port (27) together with the refrigerant. In the second step, measurement is made at the liquid side service port (27) so that most of the refrigerant on the indoor unit (13) side is recovered from the gas side shutoff valve (26) and liquid side shutoff valve (25). The vacuum pump is operated until the pressure falls below the predetermined first pressure value.

[0052] Third step>

In the third step, the first work and the second work are performed. In the first operation, as in the first and second steps, the gas side closing valve (26) is closed and the liquid side closing valve (25) is opened. Then, connect the refrigerant recovery unit (45) removed from the liquid side service port (27) to the heat source. Connect to the side port (9) and operate the vacuum pump of the refrigerant recovery unit (45). When the vacuum pump is operated, the refrigerant in the outdoor circuit (21) is recovered. In the first operation, the vacuum pump is operated until the pressure measured at the heat source side port (9) falls below a predetermined second pressure value smaller than the first pressure value.

Here, only in the first work, the refrigerant on the gas side shut-off valve (26) side of the compressor (30) in the outdoor circuit (21), that is, the four-way switching valve (33) is in the first state. If the four-way selector valve (33) is in the second state, the refrigerant between the compressor (30) outlet and the gas-side shutoff valve (26), and the compressor (30) inlet and gas side Since there is a possibility that the refrigerant between the closing valve (26) cannot be recovered, perform the second operation. In the second operation, the refrigerant recovery unit (45) from which the heat source side port (9) force has been removed is connected to the gas side service port (28). Then, the vacuum pump is operated while the gas side closing valve (26) is gradually opened from the state where the gas side closing valve (26) is closed and the liquid side closing valve (25) is opened. When the vacuum pump is operated, the refrigerant remaining in the outdoor circuit (21) after the first work is recovered. In the second operation, the vacuum pump is operated until the pressure measured at the gas service port (28) is smaller than the second pressure value and below the predetermined third pressure value. As a result, most of the refrigerant in the outdoor circuit (21) is recovered.

[0054] Note that the reason why the second operation is performed while the gas side shut-off valve (26) is gradually opened is to prevent the refrigerant in the outdoor circuit (21) from flowing into the gas side communication pipe (24). It is. That is, after the first operation, there is a possibility that the gas side connecting pipe (24) side is at a lower pressure than the outdoor circuit (21) side across the gas side shutoff valve (26). In this case, if the gas side shut-off valve (26) is suddenly opened, the refrigerant in the outdoor circuit (21) flows into the gas side connection pipe (24) that collects the refrigeration oil. Therefore, perform the second operation while gradually opening the gas-side stop valve (26).

[0055] In this embodiment, in each of the connection pipes (23, 24) in the first step and the second step, the energy loss is smaller when the near port (27, 28) force refrigerant is sucked out! /, As a result, the flow rate of the coolant increases. Therefore, much of the refrigerant adhering to the gas side connecting pipe (24) is peeled off during the first step of sucking out the refrigerant from the gas side service port (28), and the refrigerant adhering to the liquid side connecting pipe (23) is separated from the liquid side. It is often peeled off during the second step of sucking out refrigerant from the service port (27). In this embodiment, separate ports (27, 28) are used for the first step and the second step. By sucking out the refrigerant, a relatively large amount of refrigerating machine oil is peeled off in each connecting pipe (27, 28).

[0056] Further, in this embodiment, since the gas side shut-off valve (26) is closed in the first step, the refrigerant in the outdoor circuit (21) passes through the gas side shut-off valve (26) to the gas side. It is not sucked or discharged from the service port (28). Further, since the liquid side closing valve (25) is opened in the first step, the refrigerant in the outdoor circuit (21) flows into the indoor unit (13) through the liquid side closing valve (25). Therefore, compared with the case where the first step is performed with the liquid side closing valve (25) closed, the gas side service port (28) and the liquid side service port (27) are connected in the first step and the second step. The amount of refrigerant going back and forth in the indoor unit (13) increases.

[0057] Effects of one embodiment

In the present embodiment, the refrigerant is sucked out from the gas side service port (28) in the first step and the refrigeration oil adhering mainly to the gas side connection pipe (24) is peeled off, and in the second step, the liquid side service port (27 ) Force The refrigerant is sucked out to remove the refrigeration oil adhering mainly to the liquid side communication pipe (23). In other words, when all the refrigerant is sucked out from one of the ports (27, 28), the refrigeration oil in the connecting pipe (23, 24) on the opposite side of the sucking out port (27, 28) is difficult to be recovered. Service side (28) force Since the first step of sucking out the refrigerant and the second step of sucking out the refrigerant from the liquid side service port (27), a relatively large amount of refrigeration oil is connected to each connecting pipe (23, 24). Can be recovered. In addition, the conventional method in which the refrigerant filling operation is performed in order to increase the recovery amount of the refrigerating machine oil requires at least three operations, but in the method of the present invention, the first step and the second step are performed twice. Refrigerating machine oil in the gas side communication pipe (24) and the liquid side communication pipe (23) can be efficiently recovered during work. Since the amount of refrigerant to be collected is reduced by the amount not filled with the refrigerant, the time required for refrigerant collection can be shortened. Therefore, it is possible to reduce the trouble of collecting the refrigerating machine oil while efficiently collecting it.

[0058] In the present embodiment, there is no need to perform pump down for collecting the refrigerant in the refrigerant circuit (20) in the outdoor circuit (21). In addition, since pump down is not performed, it is possible to recover the refrigeration oil even when the compressor (30) is out of order.

[0059] In the present embodiment, in the first step, the gas side shut-off valve (26) is closed. This prevents the refrigerant in the outdoor circuit (21) from being sucked out of the gas side service port (28) through the gas side closing valve (26). Therefore, compared with the case where the first step is performed with the gas side shut-off valve (26) open, the flow rate of the refrigerant in the gas side communication pipe (24) is increased, so the gas side communication pipe (24) The amount of refrigerating machine oil recovered by removing the force increases.

In the present embodiment, the first step is performed with the liquid side closing valve (25) open, so that the expansion valve (36) is opened and then accumulated in the receiver (39). Liquid refrigerant may flow into the liquid side connecting pipe (23). In the first step and the second step, the amount of refrigerant going back and forth on the indoor unit (13) side between the gas side service port (28) and the liquid side service port (27) increases. That is, the total amount of refrigerant flowing through the gas side connecting pipe (24) and the liquid side connecting pipe (23) increases. Therefore, the gas side communication pipe (24) and the liquid side communication pipe (23) force can remove and collect more refrigeration oil.

[0061] Further, in the present embodiment, by performing the third step in which the refrigerant in the outdoor circuit (21) is recovered, the refrigerant remaining in the outdoor circuit (21) is reduced after the method for recovering refrigeration oil is performed. It is doing so. In particular, in this embodiment, in the third step, the first operation of recovering the refrigerant in the outdoor circuit (21) from the heat source side port (9) and the second operation of recovering from the gas side service port (28) are performed. Thus, the refrigerant in the outdoor circuit (21) is reliably recovered. Therefore, when the outdoor unit (11) is updated, the trouble of collecting the refrigerant from the removed outdoor unit (11) can be omitted. In addition, when replacing the refrigerant in the refrigerant circuit (20), the reliability of the refrigeration apparatus (10) can be improved.

[0062] In the present embodiment, in the third step, from the gas-side service port (28) to the outdoor circuit

The refrigerant in (21) is collected while the gas side shut-off valve (26) is gradually opened, so that the refrigerant in the outdoor circuit (21) is connected to the refrigerant on the gas side where the refrigerant and the refrigerant oil are recovered. It does not flow into the pipe (24). Therefore, it is possible to avoid the situation where it is necessary to recover the refrigerating machine oil if the gas side connecting pipe (24) force is also chilled after the third step.

[0063] Modification of Embodiment

A modification of the embodiment will be described. This modification is a method for recovering refrigeration oil in the case of a refrigeration apparatus (10) not provided with a heat source side port (9). The first step and the second step are the same as in the above embodiment, but only the second operation is performed in the third step. First In step 2, the refrigerant recovery unit (45) removed from the liquid side service port (27) is connected to the gas side service port (28). Then, the gas-side closing valve (26) is closed and the liquid-side closing valve (25) is opened. The vacuum pump is operated while the gas-side closing valve (26) is gradually opened.

[0064] << Other Embodiments >>

According to the above embodiment, the following configuration may be adopted.

In the above embodiment, in the first step, the vacuum pump is operated for a predetermined time! Until the pressure measured at the gas-side service port (28) is equal to or lower than the predetermined pressure value. You can make the vacuum pump run.

[0066] In the above embodiment, the first step may be performed with the liquid side closing valve (25) closed. The second step may also be performed with the liquid side shut-off valve (25) closed.

[0067] In the embodiment described above, the first step may be performed with the gas-side stop valve (26) opened.

[0068] In the above embodiment, the first work and the second work may be performed simultaneously in the third step. Specifically, separate refrigerant recovery units (45) are connected to the heat source side port (9) and the gas side service port (28). Then, the gas side closing valve (26) is closed and the liquid side closing valve (25) is opened. The vacuum pumps of both refrigerant recovery units (45) are operated while the gas side closing valve (26) is gradually opened. Let Also, do the first work after the second work.

[0069] In the above embodiment, the expansion valve (18) may be forcibly opened to perform the first step with force. In this case, compared with the case where the first step is performed with the expansion valve (18) closed, the gas service port (28) and the liquid service port (27) are not connected in the first step and the second step. The amount of refrigerant going back and forth on the indoor unit (13) side increases.

It should be noted that the above embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its application, or its use.

Industrial applicability

[0071] As described above, the present invention relates to a refrigeration apparatus including a refrigerant circuit in which a heat source unit and a utilization unit are connected by a gas side communication pipe and a liquid side communication pipe. Of refrigeration oil to recover refrigeration oil from gas side communication piping and liquid side communication piping Useful for the law.

Claims

The scope of the claims

[1] The heat source side circuit (21) in the heat source unit (11) and the utilization side circuit (22) in the utilization unit (13) are connected by the gas side communication pipe (24) and the liquid side communication pipe (23). In the refrigeration apparatus (10) that performs the refrigeration cycle with the refrigerant circuit (20) configured as described above, the gas side communication pipe (24) and the liquid side communication pipe (23) force are used to recover the refrigeration oil. And

From the gas side port (28) opened to the gas side connecting pipe (24) side of the gas side closing valve (26) provided at one end of the heat source side circuit (21), the refrigerant circuit (20) The first step of collecting the refrigerating machine oil together with a part of the refrigerant communicating with the gas side port (28), and the heat source side circuit (21) with the gas side shut-off valve (26) closed. From the liquid side port (27) that opens to the liquid side connecting pipe (23) side of the liquid side closing valve (25) provided at the other end, the liquid side port (27 And a second step of recovering the refrigerating machine oil together with a part or all of the refrigerant in the part communicating with the refrigerating machine) in order.

[2] In claim 1,

A method for recovering refrigerating machine oil, wherein the first step is performed with the gas side shut-off valve (26) closed.

[3] In claim 1 or 2,

A method for recovering refrigerating machine oil, wherein the first step and the second step are performed with the liquid side closing valve (25) opened.

[4] In claim 1,

A method for recovering refrigerating machine oil, comprising performing a third step of recovering the refrigerant of the heat source side circuit (21) after completion of the second step.

[5] In claim 4,

In the third step, the refrigerant for recovering refrigeration oil, wherein the refrigerant in the heat source side circuit (21) is recovered from the gas side port (28) while gradually opening the gas side stop valve (26).

[6] In claim 4,

In the third step, the heat source side port (9) force that opens to the heat source side circuit (21), the operation of recovering the refrigerant of the heat source side circuit (21), and the gas side shut-off valve (26) are gradually opened. While A method for recovering refrigerating machine oil, comprising: performing an operation of recovering the refrigerant of the heat source side circuit (21) from a gas side port (28).