JP3494069B2 - Refrigerant recovery device and refrigerant recovery method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerant recovery device and a refrigerant recovery method, and more particularly, to a countermeasure for ending refrigerant recovery.

[0002]

2. Description of the Related Art Conventionally, a large number of air conditioners have been known as refrigeration devices. For example, Japanese Patent Laid-Open No. 8-
As disclosed in Japanese Patent No. 100944, a compressor, a four-way switching valve, an outdoor heat exchanger, an electric expansion valve, a receiver, and an indoor heat exchanger are sequentially connected by a refrigerant pipe to form an air conditioner. There is something. The air conditioner is
The cooling operation and the heating operation can be performed.

[0003]

When the existing refrigerant pipes are to be diverted as they are, when the demand for renewal of various air conditioners including the above-mentioned air conditioner is required, the inside of the refrigerant pipes must be washed. That is, in many cases, lubricating oil or dust adheres to the inner surface of the refrigerant pipe. In particular, conventional CFC-based refrigerants and the like used mineral oil as lubricating oil, whereas HFC-based refrigerants used synthetic oil as lubricating oil. Therefore, if the lubricating oil of the mineral oil remains in the existing refrigerant pipe, foreign matter (contamination) occurs in the newly installed refrigerant circuit. There arises a problem that the foreign matter blocks the throttle mechanism or damages the compressor.

Therefore, the applicant of the present application has already proposed a pipe cleaning apparatus (Japanese Patent Application No. 9-295641). This pipe cleaning device is composed of a connection circuit connected to an existing refrigerant pipe to form a closed circuit, and a refrigeration circuit for circulating a refrigerant. The refrigeration circuit is composed of a refrigeration cycle including two heat exchangers, and each heat exchanger heats and cools the refrigerant in the closed circuit to give a conveying force, and circulates the refrigerant to separate the connection circuit. I try to remove foreign matter with.

However, in the above-mentioned pipe cleaning apparatus, when the refrigerant in the closed circuit is collected in the container after cleaning, the refrigerating circuit is driven in the same manner as in the cleaning to collect the refrigerant. Since the recovery of the refrigerant is completed according to the recovery time, there is a problem that the accurate completion determination is not performed.

That is, the recovery time is determined by the refrigerant charge amount and the pipe length. In this case, there is a problem in that a recovery residue of the refrigerant occurs if the refrigerant charge amount or the pipe length is slightly different. On the contrary, there is a problem that the recovery operation is performed for a long time despite the completion of the recovery of the refrigerant.

The present invention has been made in view of the above points, and an object thereof is to prevent uncollected refrigerant and long-term recovery operation regardless of the refrigerant filling amount and the pipe length. is there.

[0008]

SUMMARY OF THE INVENTION The present invention has been so as to determine the end of the refrigerant recovery by detecting the state of the refrigerant feed transportable.

[0009] To achieve the above object, as shown in FIG. 1, the first solving means, the refrigerant flow path connected to the container (91) a coolant (13), conveying means (40) While being heated by the carrier refrigerant, the refrigerant in the refrigerant flow passage (13) is cooled by the carrier refrigerant to apply a carrier pressure to the refrigerant in the refrigerant flow passage (13), and the refrigerant is stored in the container (91). The target is a refrigerant recovery device for recovery. Then, the present solving means detects the state of the carrying refrigerant of the carrying means (40),
When the state of the carrier refrigerant reaches a predetermined value, the refrigerant recovery ends.

The second solution is intended for a refrigerant recovery device for recovering the refrigerant in the container (91). A refrigerant flow passage (13) connected to the container (91) is provided. Further, it is constituted by a refrigeration cycle in which a carrier refrigerant circulates, the carrier refrigerant heats and pressurizes the refrigerant in the refrigerant flow passage (13), and the carrier refrigerant cools the refrigerant in the refrigerant flow passage (13). Then, the pressure is reduced, and the refrigerant is placed in a container (9
A transfer means (40) for applying a transfer pressure for recovery to the refrigerant is provided in 1). In addition, the transport means (4
0) State detection means (14) for detecting the state of the carrier refrigerant.
Is provided. In addition, based on the detection signal of the state detection means (14), the state of the conveying refrigerant Ru have <br/> recovered ending means (81) is provided to terminate the refrigerant recovery when a predetermined value.

The state detecting means (14) may be configured to detect the pressure of the carrying refrigerant of the carrying means (40), and the recovery ending means (81) is the carrying means (40).
The refrigerant recovery may be completed when the pressure of the carrier refrigerant is reduced to a predetermined value.

Further, the state detecting means (14) may be arranged to detect the liquid amount of the carrying refrigerant of the carrying means (40), and the recovery end means (81) may be arranged to detect the carrying refrigerant. liquid volume but it may also be configured to terminate the refrigerant recovery drops to a predetermined value.

Another means for solving the problem is a refrigerant recovery method for recovering the refrigerant in the container (91). Then, the refrigerant in the refrigerant flow passage (13) connected to the container (91) is
While being heated and pressurized by the carrier refrigerant of the carrier means (40) constituted by a refrigeration cycle, the refrigerant flow passage (1
The method further includes a step of cooling the refrigerant in (3) with a carrier refrigerant to reduce the pressure in the refrigerant flow path (13), applying a carrier pressure to the refrigerant, and collecting the refrigerant in the container (91). in addition,
When the state of the carrying refrigerant reaches a predetermined value based on the detection signal of the state detecting means (14) for detecting the state of the carrying refrigerant of the carrying means (40), the recovery end means (81) ends the refrigerant recovery. It has a process to do.

That is, in the present solution means, a carrier pressure is applied to the refrigerant in the refrigerant flow passageway (13), and for example, a carrier pressure is applied to the refrigerant in the refrigerant flow passageway (13) by the transfer means (40). 91) to you recover the refrigerant.

Specifically, the carrying means (40) is composed of a so-called heat pump, and heats and pressurizes the refrigerant in the refrigerant flow passage (13) with the carrying refrigerant, and at the same time, the refrigerant flows with the carrying refrigerant. Cool the refrigerant in (13) to reduce the pressure,
A carrier pressure is applied to the refrigerant. Hand, when the upper Symbol recovery, the state detecting means (14) detects the state of conveyance for the refrigerant of the conveying means (40), based on a detection signal of the state detection means (14), the state of the conveying refrigerant When the predetermined value is reached, the recovery end means (81) ends the refrigerant recovery.

In particular, the state detecting means (14) may detect the pressure of the carrying refrigerant of the carrying means (40) or the liquid amount of the carrying refrigerant. And the collection end means (81)
Ends the refrigerant recovery when the pressure of the carrier refrigerant in the carrier means (40) drops to a predetermined value or when the liquid amount of the carrier refrigerant drops to a predetermined value.

[0017]

Effect of the Invention] Thus, according to the present solving means, since determining the end of the refrigerant recovery such as by the pressure of the conveying refrigerant conveyance means (40), the state detecting means for various sensors (1
4) can be combined. As a result, it is possible to omit a dedicated sensor for determining the end,
An increase in the number of parts can be suppressed, and the configuration can be simplified.

In particular, when the carrier means (40) heats and cools the refrigerant in the refrigerant flow passage (13) with the carrier refrigerant to apply the carrier pressure to the refrigerant, the recovery speed is increased and the recovery rate is improved. By achieving the above, the overall efficiency at the time of collection can be improved.

Further, it is possible to perform highly reliable refrigerant recovery with less troubles as compared with mechanical pumps.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, will be described in detail with reference to embodiments of the present invention with reference to the drawings. Therefore, first of all,
Explain the prerequisite technology as a prerequisite.

As shown in FIG. 1, a pipe cleaning device (10)
Is for cleaning the refrigerant pipes (2A, 2B) in the existing refrigerant circuit using the secondary refrigerant system, and is connected to the existing refrigerant pipes (2A, 2B). Note that FIG. 1 shows two existing refrigerant pipes (2A, 2B). The existing refrigerant pipes (2A, 2B) are communication pipes that connect an outdoor unit and an indoor unit in an existing refrigerant circuit (not shown), and are vertical pipes in this embodiment.

A first cleaning circuit (11) is connected to one end of the two existing refrigerant pipes (2A, 2B), and a second cleaning circuit (12) is connected to the other end. First cleaning circuit (11)
Is composed of one connecting pipe, and both ends are joints (21, 21)
Is connected to two existing refrigerant pipes (2A, 2B). The connection part of the first cleaning circuit (11) is, for example, a part to which the indoor unit is connected in the existing refrigerant circuit.

The second cleaning circuit (12) has a connection circuit (3
0) and a refrigeration circuit (40). Both ends of the connection circuit (30) are connected to two existing refrigerant pipes (2A, 2B) via joints (21, 21). And the above 2
The existing refrigerant pipes (2A, 2B) of the book and the connection circuit (30) of the first cleaning circuit (11) and the second cleaning circuit (12) constitute a closed circuit (13). The connection part of the connection circuit (30) is, for example, a part to which the outdoor unit is connected in the existing refrigerant circuit.

The closed circuit (13) is provided in the existing refrigerant pipe (2A,
2B) is filled with a secondary refrigerant for cleaning to form a refrigerant flow passage. As the secondary refrigerant, for example, a new clean refrigerant used for newly installed air conditioning is used. Specifically, the secondary refrigerant is R-407C or R-4.
It is an HFC type refrigerant such as 10A.

The connection circuit (30) includes a first closing valve (V1).
And check valve (31), separator (50), pressurizing / depressurizing part (60) and second
The shut-off valve (V2) and the shut-off valve (V2) are sequentially connected by a connecting pipe (34).

The separator (50) is constituted by a separation heat exchange coil (52) and a filter (53) housed in a tank (51), and has a separating means for separating foreign matters such as lubricating oil from the secondary refrigerant. I am configuring. The tank (51) stores the liquid-phase secondary refrigerant flowing through the existing refrigerant pipes (2A, 2B).

The separation heat exchange coil (52) is connected to the refrigerating circuit (40) described later, and the two liquid phases in the tank (51) are connected.
It constitutes a heating means for heating and evaporating the next refrigerant.
The filter (53) is attached to the upper part of the tank (51) and removes foreign substances from the secondary refrigerant by passing the gas phase secondary refrigerant evaporated by heating the separation heat exchange coil (52). Constitutes a means.

The pressurizing / depressurizing part (60) forms two parallel passages (61, 61) in the middle of the connecting pipe (34), and also has a first transfer heat exchanger (7A) and a second transfer heat exchanger. (7B) is provided in each parallel passage (61, 61). Further, each transfer heat exchanger (7A, 7A,
7B) are provided with check valves (62, 62, ...) Allowing the refrigerant to flow in only one direction on the upstream side and the downstream side.

The refrigeration circuit (40) is a compression circuit section (4C).
And a transfer circuit section (4A) to constitute an independent transfer means for one refrigeration cycle. The carrier circuit section (4A)
However, it is connected to the compression circuit section (4C) by a four-way switching valve (42) so that the refrigerant flow direction is reversible.
As the refrigerant with which the refrigeration circuit (40) is filled, that is, the primary refrigerant that is a carrier refrigerant, various refrigerants such as an HFC refrigerant in addition to R22 are used.

The compression circuit section (4C) comprises an air-cooled condenser (4e) on the discharge side of the compressor (41) and an accumulator (46) on the suction side of the compressor (41). There is. The air-cooled condenser (4e) suppresses a rise in high pressure on the discharge side of the compressor (41). That is, when the condensation amount of the primary refrigerant decreases, the high pressure on the discharge side of the compressor (41) increases. When the high pressure becomes equal to or higher than a predetermined value, the air cooling fan (4f) is driven so that the air cooling condenser (4e) condenses the refrigerant discharged from the compressor (41).

On the other hand, the transfer circuit section (4A) is constructed by connecting a first transfer heat exchanger (7A), a rectifying circuit (47) and a second transfer heat exchanger (7B) in series. . And
A one-way passage (48) is connected to the rectifier circuit (47).

The rectifier circuit (47) is configured as a bridge circuit having four one-way valves (CV). Of the four connection points of the rectifier circuit (47), two are 1
The directional passage (48) is connected, and the other two connecting points are respectively the first transfer heat exchanger (7A) and the second transfer heat exchanger (7A).
B) is connected.

A separation heat exchange coil (52) and an expansion valve (EV) are sequentially connected to the one-way passage (48) from the upstream side. The expansion valve (EV) constitutes a throttle mechanism whose degree of superheat is controlled. The temperature sensing tube (TB) of the expansion valve (EV) is attached to the inflow side of the accumulator (46). The separation heat exchange coil (52) is housed in the tank (51) of the separator (50) as described above.

The two transfer heat exchangers (7A, 7B) are plate heat exchangers, for example. Each of the transfer heat exchangers (7A, 7B) is configured to alternately repeat the cooling operation and the pressurizing operation. That is, the transfer heat exchangers (7A, 7B) alternately serve as cooling means and pressurizing means.

The cooling operation is an operation of cooling the gas-phase secondary refrigerant having undergone the phase change in the separator (50), changing the phase to the liquid phase, and reducing the pressure. The pressurizing operation is an operation of heating and pressurizing the liquid-phase secondary refrigerant in the liquid phase.

Specifically, for example, in the state where the secondary refrigerant in the liquid phase for cleaning is accumulated in the first transfer heat exchanger (7A) on the left side of FIG. 1, the second transfer heat exchange on the right side of FIG. The gas-phase secondary refrigerant for cleaning is stored in the vessel (7B). In this state, the first transfer heat exchanger (7A) functions as a pressurizing unit and the second transfer heat exchanger (7B) functions as a cooling unit.

The high-temperature primary refrigerant discharged from the compressor (41) heats and raises the pressure of the liquid-phase secondary refrigerant in the first transfer heat exchanger (7A) to impart a transfer pressure to the secondary refrigerant. Is pushed out to the existing refrigerant piping (2A, 2B). On the other hand, the primary refrigerant is decompressed by the expansion valve (EV) via the separation heat exchange coil (52) and evaporated in the second transfer heat exchanger (7B). The primary refrigerant cools the gas-phase secondary refrigerant, changes the phase of the secondary refrigerant to the liquid phase, and reduces the pressure. As a result, the second carrier heat exchanger (7B) sucks the gas-phase secondary refrigerant from the separator (50) and stores the secondary refrigerant.

After that, the first transfer heat exchanger (7A) is switched to the cooling means, and the second transfer heat exchanger (7B) is switched to the pressurizing means. Then, the high temperature 1 discharged from the compressor (41)
The secondary refrigerant flows into the second carrier heat exchanger (7B) and pushes the liquid-phase secondary refrigerant into the existing refrigerant pipes (2A, 2B). On the other hand, the primary refrigerant evaporates in the first carrier heat exchanger (7A), cools the gas-phase secondary refrigerant, and stores the secondary refrigerant in the first carrier heat exchanger (7A). This operation is repeated.

A low pressure sensor (P1) is provided on the suction side of the compressor (41) in the compressor circuit (4C).
High pressure sensor (P2) and temperature sensor (T
2) is provided. The low pressure switch (LPS) is
It constitutes a detection means for detecting the pressure of the secondary refrigerant, the saturation temperature equivalent to the pressure, and the like.

Further, the connecting pipe (3
In 4), a low pressure switch (LPS) is provided downstream of the separator (50). The low-pressure pressure switch (LPS) is you detect a pressure or pressure corresponding saturation temperature of the secondary coolant.

In the refrigeration circuit (40), the discharge pressure of the compressor (41) becomes a predetermined value or more, the discharge temperature of the compressor (41) becomes a predetermined value or less, or the separator (50) The four-way switching valve (42) is configured to be switched when the internal pressure becomes equal to or higher than a predetermined value or under any condition. In the refrigeration circuit (40), the flow direction of the refrigerant in the transfer circuit section (4A) is switched by switching the four-way switching valve (42).

For example, one of the transfer heat exchangers (7A, 7B)
When the (cooling side) is filled with the liquid-phase secondary refrigerant, the heat exchange amount of the primary refrigerant in the carrier heat exchanger (7A, 7B) decreases. As a result, since the expansion valve (EV) is under superheat control, the throttle amount increases and the low pressure on the suction side of the compressor (41) decreases. This low pressure is the low pressure sensor (P1)
Is detected, and when it becomes less than a predetermined value, the four-way switching valve (42) is switched.

Further, the connection circuit (30) is provided with a hot gas passage (15) for filling and recovering the secondary refrigerant and an auxiliary circuit (90). That is, the pipe cleaning device (10) of the present embodiment is configured to function as a refrigerant recovery device that recovers the secondary refrigerant in addition to cleaning the pipe.

The hot gas passage (15) supplies the high-temperature and high-pressure secondary refrigerant to the existing refrigerant pipes (2A, 2B) after cleaning, and remains in the existing refrigerant pipes (2A, 2B). The next refrigerant liquid is evaporated and recovered. The inflow side of the hot gas passage (15) is branched into two, and the two inflow ends are parallel passages (61, 6) on the inflow side of each of the transfer heat exchangers (7A, 7B).
1) connected to. In addition, the hot gas passage (1
The outflow end of 5) is connected between the second shutoff valve (V2) and the existing pipe (2B). A one-way valve (CV) is provided at a branch portion on the inflow side of the hot gas passage (15), and a third closing valve (V3) is provided at a confluent portion on the outflow side.

The auxiliary circuit (90) includes a refrigerant cylinder (91) as a container and four auxiliary passages (92 to 95).

The first auxiliary passage (92) is branched into two outflow sides from a main part on the inflow side. An inflow end of the first auxiliary passage (92) communicates with the refrigerant cylinder (91), and two outflow ends of the first auxiliary passage (92) are connected to the parallel passages (61, 61) on the downstream side of the connection portion of the hot gas passage (15). It is connected. A fourth closing valve (V4) is provided in the main part on the inflow side of the first auxiliary passage (92), and a one-way valve (CV) is provided in the branch part on the outflow side.

The third auxiliary passage (94) is the sixth closing valve (V6)
Is provided. One end of the third auxiliary passage (94) communicates with the refrigerant cylinder (91), and the other end of the third auxiliary heat exchanger (7).
It is connected to the parallel passage (61) on the outflow side of B).

The second auxiliary passage (93) is the fifth closing valve (V5)
Is provided. One end of the second auxiliary passage (93) is
It is connected to the third auxiliary passage (94) on the downstream side of the sixth closing valve (V6), and the other end is on the main portion of the first auxiliary passage (92) on the downstream side of the fourth closing valve (V4). It is connected.

The fourth auxiliary passage (95) is the seventh closing valve (V7)
Is provided. One end of the fourth auxiliary passage (95) is
The hot gas passage (15) is connected to the gathering portion on the upstream side of the third closing valve (V3), and the other end is connected to the first auxiliary passage (9).
It is connected to the main part of 2) on the upstream side of the fourth closing valve (V4).

A charging circuit (9S) for charging the closed circuit (13) with the secondary refrigerant is provided with a part of the hot gas passage (15), the fourth auxiliary passage (95) and the second auxiliary passage (95). It is formed by the auxiliary passage (93), a part of the first auxiliary passage (92) and a part of the second auxiliary passage (93).

A recovery circuit (9R) for recovering the secondary refrigerant into the refrigerant cylinder (91) includes a hot gas passage (15), a first auxiliary passage (92) and a third auxiliary passage ( 94)
It is formed by and.

The refrigeration circuit (40) includes a controller (8
Controlled by 0). The controller (80) receives the detection signals of the low-pressure pressure sensor (P1), the high-pressure pressure sensor (P2), the temperature sensor (T2) and the low-pressure pressure switch (LPS), while the recovery end section (81) is It is provided.

The recovery end section (81) ends the refrigerant recovery when the pressure of the secondary refrigerant in the closed circuit (13) drops to a predetermined value based on the detection signal of the low pressure switch (LPS). Are configured.

That is, the secondary refrigerant in the closed circuit (13) is
As shown in FIG. 2, the refrigerant recovery rate A increases and the secondary refrigerant pressure B decreases as the refrigerant recovery progresses. Therefore, when this secondary refrigerant pressure B drops to a predetermined value, it is possible to determine the end of refrigerant recovery. Therefore, the recovery end unit (81) of the present embodiment ends the recovery of the refrigerant when the pressure of the secondary refrigerant drops to a predetermined value.

<Cleaning Operation of Existing Refrigerant Pipe> Next, the existing refrigerant pipe (2
The cleaning operation of A and 2B) will be explained including the recovery method.

First, in the existing refrigerant circuit, the outdoor unit and the indoor unit are removed from the existing refrigerant pipes (2A, 2B) which are the connecting pipes. Then, the first cleaning circuit (11) is connected to the upper ends of the two existing refrigerant pipes (2A, 2B), while the second cleaning circuit is connected to the lower ends of the two existing refrigerant pipes (2A, 2B). Closed circuit (13) by connecting the connection circuit (30) of (12)
To form.

Next, the closed circuit (13) is filled with the secondary refrigerant. That is, in the initial stage of filling, for example, the closed circuit (13) is brought into a vacuum state, and the refrigerant cylinder (91) is connected to the first auxiliary passage (92). Then, the fourth closing valve (V4) is opened to fill the closed circuit (13) with the secondary refrigerant from the refrigerant cylinder (91) through the first auxiliary passage (92).

Further, when additionally charging the secondary refrigerant, in the auxiliary circuit (90), the third closing valve (V3), the fourth closing valve (V4) and the sixth closing valve (V6) are closed, while Open the 7th stop valve (V7) and the 5th stop valve (V5).

In this state, when the refrigeration circuit (40) is driven, the hot gas in the closed circuit (13) becomes hot from the upstream side of the transfer heat exchanger (7A, 7B) as shown by the solid arrow in FIG. It flows into the refrigerant cylinder (91) from the gas passage (15) through the fourth auxiliary passage (95). The inside of the refrigerant cylinder (91) is pressurized by this hot gas, and the refrigerant in the refrigerant cylinder (91), that is, the secondary refrigerant, passes through the third auxiliary passage (94) and the second auxiliary passage (93). It passes through the first auxiliary passageway (92) and is filled in the closed circuit (13).

Subsequently, the operation for cleaning the pipe is started, and the above third step is performed.
The refrigeration circuit (40) of the second cleaning circuit (12) is driven while the closing valve (V3) to the seventh closing valve (V7) are closed. That is, the compressor (41) is driven to circulate the primary refrigerant. The high-temperature high-pressure primary refrigerant discharged from the compressor (41) flows through the air-cooled condenser (4e), and then through the four-way switching valve (42) to one of the transfer heat exchangers (7A or 7B).

Therefore, in a state where the liquid-phase secondary refrigerant for cleaning is accumulated in the first transfer heat exchanger (7A) on the left side of FIG.
The state in which the secondary refrigerant in the gas phase for cleaning is accumulated in the second transfer heat exchanger (7B) on the right side of FIG. 1 will be described.

In this state, the four-way switching valve (42) is switched to the state shown by the solid line in FIG. 1, the high temperature primary refrigerant flows through the first transfer heat exchanger (7A), and the primary refrigerant is condensed. Liquid phase 2
The next refrigerant is heated to raise the pressure. Due to this boosting, the secondary refrigerant in the liquid phase is transferred to the existing refrigerant pipes (2A, 2B) by carrying the carrying pressure, that is, the carrying force, flowing out of the first carrying heat exchanger (7A).

At this time, the secondary refrigerant first flows through the large-diameter gas-side existing refrigerant pipe (2B), and then the first cleaning circuit (11).
Through a small diameter liquid side existing refrigerant pipe (2A).

Further, the primary refrigerant having passed through the first carrier heat exchanger (7A) passes through the rectifier circuit (47) and the one-way passage (48), and the separation heat exchange coil (52) of the separator (50). And the liquid-phase secondary refrigerant accumulated in the tank (51) of the separator (50) is evaporated.

Thereafter, the condensed primary refrigerant is decompressed by the expansion valve (EV) and flows into the second transfer heat exchanger (7B), where
The next refrigerant evaporates. By this evaporation, the gas-phase secondary refrigerant for cleaning is cooled and changes into a liquid phase. Due to this phase change, the secondary refrigerant is reduced in pressure and sucks the gas phase secondary refrigerant from the separator (50), and also stores the secondary refrigerant in the second transfer heat exchanger (7B).

On the other hand, the primary refrigerant evaporated in the second transfer heat exchanger (7B) is passed through the four-way switching valve (42) to the compressor (41).
Return to and repeat this operation.

After that, when the second carrier heat exchanger (7B) is filled with the liquid-phase secondary refrigerant, the four-way switching valve (42) is switched. That is, when the heat exchange amount of the primary refrigerant in the second transfer heat exchanger (7B) decreases, the expansion valve (EV) controls the superheat degree, so the throttle amount increases and the compressor (4
The low pressure on the suction side of 1) decreases. And, for example,
The low-pressure pressure sensor (P1) detects this low-pressure pressure, and when it falls below a predetermined value, the four-way switching valve (42) is switched.

By switching the four-way switching valve (42), the primary refrigerant discharged from the compressor (41) flows into the second carrier heat exchanger (7B), and the secondary refrigerant is transferred to the existing refrigerant pipes (2A, 2B). )
Send to. On the other hand, the primary refrigerant is the separation heat exchange coil (52).
Via the first transfer heat exchanger (7A) to evaporate and cool the secondary refrigerant and store the secondary refrigerant. Repeat this operation 2
The next refrigerant is circulated in the closed circuit (13).

This liquid-phase secondary refrigerant is the existing refrigerant pipe (2
A, 2B), and foreign matter such as lubricating oil adhering to the inner surface of the existing refrigerant pipe (2A, 2B) melts. This secondary refrigerant is
In the separator (50), the separation heat exchange coil (52) is heated to evaporate and foreign matter is separated and accumulated in the tank (51). At the same time, when the secondary refrigerant passes through the filter (53), foreign matters such as lubricating oil mixed in with the secondary refrigerant are removed, and the secondary refrigerant flows into one of the above-mentioned carrier heat exchangers (7A or 7B). , Repeat this operation.

When the amount of condensation of the primary refrigerant decreases during the transportation of the secondary refrigerant, the high pressure on the discharge side of the compressor (41) increases. The high pressure is detected by the high pressure sensor (P2), and when the pressure becomes equal to or higher than a predetermined value, the air cooling fan (4f) is driven. As a result, part of the high-temperature high-pressure primary refrigerant is condensed in the air-cooled condenser (4e), and then the gas-liquid two-phase primary refrigerant is
It flows through the four-way switching valve (42) to one of the transfer heat exchange coils (71 or 72). The condensation of the air-cooled condenser (4e) reduces the high pressure of the primary refrigerant.

After the cleaning operation is completed, a secondary refrigerant recovery operation is performed. That is, the second closing valve (V2), the fifth closing valve (V5), and the seventh closing valve (V7) are kept closed while the first closing valve (V1), the third closing valve (V3), and the fourth closing valve. (V4) and 6th stop valve (V6) are opened.

Depending on this valve state, the refrigeration circuit (4
0) continuously, as shown by the dashed line arrow in FIG.
Hot gas in the closed circuit (13) is supplied from the hot gas passage (15) to the existing refrigerant pipes (2A, 2B) and the like.

That is, in the carrier heat exchanger (7A or 7B) that heats and pressurizes the secondary refrigerant, the secondary refrigerant has the highest temperature and pressure immediately before switching the four-way switching valve (42). . Therefore, the high-temperature and high-pressure gas-phase secondary refrigerant is sent from the hot gas passage (15) to the existing refrigerant pipes (2A, 2B). With this high temperature secondary refrigerant, existing refrigerant piping (2A,
Liquid phase secondary refrigerant remaining in 2B) is evaporated and pushed out.

On the other hand, the refrigerant cylinder (91) is connected to the first auxiliary passage (92) and the third auxiliary passage (94). The first auxiliary passage (92) communicates with the transfer heat exchanger (7A or 7B) that cools and reduces the pressure of the secondary refrigerant through the opening of the fourth closing valve (V4). By this communication, the refrigerant cylinder (91) is degassed, and the inside of the refrigerant cylinder (91) becomes low in pressure.

In this state, the four-way switching valve (42)
The recovery process is executed by switching between the two, and the push-out operation and the pooling operation of both transfer heat exchangers (7A or 7B) are continuously performed.
Since the third auxiliary passage (94) communicates with the refrigerant cylinder (91) through the opening of the sixth closing valve (V6), the secondary extruded from the one transfer heat exchanger (7A or 7B). The refrigerant is collected in the refrigerant cylinder (91) through the third auxiliary passage (94).

After that, when the low pressure switch (LPS) is actuated in the refrigerant recovery end step, the recovery end section (81)
Ends the collection operation. That is, as shown in FIG. 2, when the secondary refrigerant in the closed circuit (13) is almost recovered and the refrigerant recovery rate A increases, the secondary refrigerant pressure B decreases. On the other hand, the low pressure switch (LPS) constantly detects the pressure of the secondary refrigerant and operates at a predetermined low pressure value. Therefore, when the secondary refrigerant pressure B decreases to a predetermined value based on this detection signal, the recovery is completed. The section (81) stops the compressor (41) and the like to end the recovery operation.

After completion of this refrigerant recovery, the first cleaning circuit (11) and the second cleaning circuit (12) are connected to the existing refrigerant pipes (2A, 2).
It is outside take from B).

As described above , since the refrigerant recovery is completed by the decrease of the secondary refrigerant pressure, the recovery operation can be accurately performed.

That is, the recovery operation can be accurately terminated regardless of the filling amount of the secondary refrigerant and the pipe length of the existing refrigerant pipes (2A, 2B), so that the residual refrigerant can be prevented from being recovered. Further, it is possible to reliably prevent the situation where the recovery operation is performed despite the completion of the recovery of the refrigerant.

<Main Part of Embodiment> Next, a main part of the embodiment of the present invention will be described.

In the present embodiment, instead of the above-described base technology determining the end of the refrigerant recovery based on the pressure of the secondary refrigerant, the end of the refrigerant recovery is determined based on the pressure of the primary refrigerant. It is a thing.

That is, as shown in FIG. 3C, the four-way switching valve (42) of the refrigeration circuit (40) has the low pressure detected by the low pressure sensor (P1) as described in the first embodiment. Based on this, switching is performed at switching points a, b and c.

On the other hand, the low pressure sensor (P1) is
The low pressure LP of the primary refrigerant on the suction side of 1) is detected, and the high pressure sensor (P2) detects the high pressure HP of the primary refrigerant on the discharge side of the compressor (41).

The high pressure HP of the primary refrigerant increases immediately after the switching points a and b of the four-way switching valve (42) and gradually decreases before switching.

The low-pressure pressure LP of the primary refrigerant sharply drops immediately after the switching points a and b of the four-way switching valve (42) (see FIG. 3).
(See D), then rises once, and then falls again immediately before switching (see FIG. 3E). This sudden drop D at the initial stage of switching is caused by the discharge of the primary refrigerant of the compressor (41). On the other hand, the decrease E at the final stage of switching is reduced due to the reduction of heat exchange due to the recovery of the secondary refrigerant.

Therefore, similar to the base technology , the cleaning operation is completed, the secondary refrigerant recovery step is executed, and then the refrigerant recovery end step is executed, and the low pressure LP at the end of the switching (see FIG. 3E).
When the reference value becomes lower than a predetermined value, the recovery end unit (81) stops the compressor (41) and the like, and ends the recovery operation.

Therefore, while the low pressure sensor (P1) constitutes the state detecting means (14), the recovery end portion (81)
With respect to the sudden drop D at the initial stage of switching, mask processing or the like is performed so that the end determination is not performed.

As described above, in this embodiment, since the completion of the refrigerant recovery is determined by the pressure of the primary refrigerant, the low pressure sensor (P1) can be used also as the state detecting means (14). As a result, a dedicated sensor or the like for determining the end can be omitted, so that an increase in the number of parts can be suppressed and the configuration can be simplified. Other configurations, operations and effects are similar to those of the base technology .

[0089]

Other Embodiments of the Invention In the above embodiment , 1
Although the end of the refrigerant recovery is determined by the low pressure LP of the next refrigerant, the end of the refrigerant recovery may be determined by the liquid refrigerant amount of the primary refrigerant.

That is, although not shown, the first transfer heat exchanger (7A) and the second transfer heat exchanger (7B) have a state detecting means (14) such as a float switch for detecting the liquid refrigerant amount of the primary refrigerant. ) Is provided. Then, when the amount of liquid refrigerant detected by the state detecting means (14) decreases to a predetermined value, the recovery end section (81) ends the recovery operation.

Further, in the above embodiment , the pipe cleaning and the refrigerant recovery have been described, but the refrigerant recovery device of the present invention may perform only the refrigerant recovery. That is,
The connection circuit (30) does not have to include the separator (50), and the connection circuit (30) may be connected to various refrigerant injection parts.

Further, the pipe cleaning device (10) of the embodiment may function as a refrigerant regenerating device. That is, both ends of the connection circuit (30) in the second cleaning circuit (12) are connected to a container such as a refrigerant cylinder (91). Then, the refrigerant filled in this container is used as a secondary refrigerant to circulate in the closed circuit (13) as in the cleaning operation. By this circulation, the refrigerant is regenerated in the separator (50).

[Brief description of drawings]

FIG. 1 is a refrigerant circuit diagram showing an embodiment of the present invention.

FIG. 2 is a characteristic diagram of the recovery rate and pressure of the secondary refrigerant with respect to the time of refrigerant recovery.

FIG. 3 is a characteristic diagram of the switching timing of the four-way switching valve and the high pressure and low pressure of the primary refrigerant with respect to the time of refrigerant recovery in the embodiment .

[Explanation of symbols]

10 Pipe cleaning device 12 Second cleaning circuit 13 Closed circuit (refrigerant flow passage) 14 State detection means 15 hot gas passage 30 connection circuit 40 Refrigeration circuit (transportation means) 50 separator 7A, 7B carrier heat exchanger 80 controller 81 Collection end section (Collection end means) 90 Auxiliary circuit 91 Refrigerant cylinder (container)

Continuation of the front page (56) Reference JP-A-6-347142 (JP, A) JP-A-7-120113 (JP, A) JP-A-10-253203 (JP, A) JP-A-11-83245 (JP , A) International publication 98/044304 (WO, A1) (58) Fields investigated (Int.Cl. ⁷ , DB name) F25B 45/00

Claims (5)

(57) [Claims] 1. A refrigerant flow passage (1) connected to a container (91).
The refrigerant in 3) is heated by the carrier refrigerant in the carrier means (40), and the refrigerant in the refrigerant flow passage (13) is cooled by the carrier refrigerant to apply a carrier pressure to the refrigerant in the refrigerant flow passage (13). A refrigerant recovery device for applying and recovering the refrigerant in a container (91), detecting the state of the carrier refrigerant of the carrier means (40), and collecting the refrigerant when the condition of the carrier refrigerant reaches a predetermined value. Refrigerant recovery device to be finished. 2. A refrigerant recovery device for recovering a refrigerant in a container (91), comprising a refrigerant flow passage (13) connected to the container (91) and a refrigeration cycle in which a carrier refrigerant is circulated. The carrier refrigerant heats and pressurizes the refrigerant in the refrigerant flow passage (13), and the carrier refrigerant also causes the refrigerant flow passage (13) to flow.
A means (40) for cooling and reducing the pressure of the refrigerant and applying a pressure for carrying the refrigerant to the container (91).
A state detection means (14) for detecting the state of the transfer refrigerant of the transfer means (40), and when the state of the transfer refrigerant reaches a predetermined value based on the detection signal of the state detection means (14), A refrigerant recovery device comprising: a recovery end means (81) for ending recovery. 3. The refrigerant recovery device according to claim 2, wherein the state detection means (14) is configured to detect the pressure of the transfer refrigerant of the transfer means (40), while the recovery end means (81). Is a refrigerant recovery device configured to terminate the recovery of the refrigerant when the pressure of the refrigerant for transportation of the transportation means (40) drops to a predetermined value. 4. The refrigerant recovery device according to claim 2, wherein the state detection means (14) is configured to detect the liquid amount of the transfer refrigerant of the transfer means (40), while the recovery end means (81). ) Is a refrigerant recovery device configured to terminate the recovery of the refrigerant when the liquid amount of the carrier refrigerant decreases to a predetermined value. 5. A refrigerant recovery method for recovering a refrigerant in a container (91), wherein the refrigerant in a refrigerant flow passage (13) connected to the container (91) is a conveying means (40) constituted by a refrigeration cycle. ) Is heated and pressurized by the carrier refrigerant, the refrigerant in the refrigerant flow passage (13) is cooled by the carrier refrigerant to cool the refrigerant in the refrigerant flow passage (13), and the carrier pressure is applied to the refrigerant. Based on the detection signal of the state detecting means (14) for detecting the state of the carrying refrigerant of the carrying means (40) and the step of collecting the refrigerant in the container (91). And a step of terminating the recovery of the refrigerant by the recovery terminating means (81).