JP2003193974A - Two-stage compression refrigerating machine, and filling method for refrigerating machine oil and refrigerant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To fill a closed housing of a two-stage compressor with a sufficient quantity of a refrigerating machine oil by filling the closed housing of the two-stage compressor without passing it through a compression mechanism part in which flow resistance is high, with the refrigerating machine oil, in a two-stage compression refrigerating machine using the two-stage compressor. <P>SOLUTION: Piping for filling refrigerant communicating with the inside of the closed housing of the two-stage compressor housing a low stage side compression mechanism part and a high stage side compression mechanism part is provided to fill a refrigerant filling instrument connected to the piping for filling refrigerant with the refrigerant. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-stage compression refrigeration system using a two-stage compressor, and a method for filling refrigerating machine oil and refrigerant.

[0002]

2. Description of the Related Art A conventional method for filling refrigerating machine oil and refrigerant in a refrigerating system is to connect a refrigerating machine oil filling device to the inlet side of an evaporator and fill the refrigerating machine oil into the refrigerant circuit from this position, and then evaporate. The refrigerant tank is connected to the same inlet side position of the container, the refrigerant is filled from this position, and the refrigerating machine oil is pushed into the closed housing of the two-stage compressor by the pressure of the refrigerant.

By the way, in recent years, the problem of destruction of the global environment by refrigerants has been highlighted, and alternatives such as CFCs and natural refrigerants have been reviewed. Further, regarding the heat pump type water heater, there is a demand for increasing the hot water temperature.
As a measure against this demand, a refrigerant whose discharge gas temperature is higher than that of the conventional HCFC22, such as HFC32,
Alternative CFCs such as mixed refrigerants containing HFC32 and natural refrigerants such as carbon dioxide and ammonia have begun to be used.

In a refrigerating device such as a heat pump type hot water supply device using such a CFC substitute or natural refrigerant, it is considered more efficient to use a two-stage compressor because the pressure difference between high and low becomes large. Has been. Further, as a two-stage compressor for such an application, the intermediate-pressure gas refrigerant discharged from the low-stage compression mechanism section is discharged into the sealed housing of the two-stage compressor, and the intermediate refrigerant discharged into this sealed housing is discharged. A gas refrigerant having a pressure is developed by an external pipe arranged outside the hermetically sealed housing so as to be guided to the suction port of the high-stage compression mechanism.

However, a specific and sufficient study has not yet been conducted on the method of filling the refrigerating machine oil and the refrigerant applied to the two-stage compression refrigerating apparatus using such a two-stage compressor. Therefore, for such a two-stage compression type refrigerating apparatus, the conventional method of filling the refrigerating machine oil and the refrigerant has been adopted as it is.

An example of applying the conventional refrigerating machine oil and refrigerant filling method to a refrigerating apparatus using the above-described two-stage compressor will be described with reference to FIG. In the two-stage compression refrigeration system shown in FIG. 5, a two-stage compressor 1, a water heat exchanger 2, an expansion device 3 such as an electric expansion valve, an outdoor heat exchanger 4, and an accumulator 5 are sequentially connected to form a refrigerant circuit. Has been done. This refrigerant circuit is filled with HFC32, which has a discharge gas temperature higher than that of the HCFC22, alternative CFCs such as a mixed refrigerant containing HFC32, or natural refrigerants such as carbon dioxide and ammonia. Freezing operation is performed by the supercritical refrigeration cycle. Moreover, this refrigerating apparatus shows what is used as a heat source device of a water heater. In this refrigeration system, a hot water storage tank 7 for storing heated hot water is connected to the water heat exchanger 2.

The two-stage compressor 1 contains a low-stage compression mechanism 11 and a high-stage compression mechanism 12 inside a hermetically sealed housing. Then, the discharge gas (gas refrigerant having an intermediate pressure) from the low-stage compression mechanism portion 11 is once released into the closed housing, and the released intermediate-pressure gas refrigerant is passed through the external pipe 6 to the high-stage compression mechanism. Inhaled into the part 12. In addition,
The discharge gas discharged from the high-stage compression mechanism section 12 is sent to the water heat exchanger 2.

The water heat exchanger 2 heats the hot water for hot water supply with the gas refrigerant discharged from the two-stage compressor 1. The water heat exchanger 2 and the hot water storage tank 7 are connected to each other by a water pipe 9 having a pump 8 interposed therebetween, and the hot water supplied by the water heat exchanger 2 is supplied to the hot water storage tank via the water pipe 9. It is stored in 7. Expansion device 3
Is an electric expansion valve that reduces the pressure of the high-pressure gas refrigerant cooled by the water heat exchanger 2.

The outdoor heat exchanger 4 exchanges heat between the gas-liquid two-phase refrigerant decompressed by the expansion device 3 and the outside air as the heat source fluid, and functions as an evaporator in this refrigeration system. A refrigerant filling branch pipe 20 is provided on the inlet side of the outdoor heat exchanger 4. Refrigerant filling branch pipe 20
Is a pipe having a small diameter connected to a point A of the inlet side pipe of the outdoor heat exchanger 4, and an opening / closing valve 21 is attached to the tip of the refrigerant filling branch pipe 20. Further, the refrigerant filling branch pipe 20 is used for refrigerant filling by connecting the refrigerant tank 23. In this conventional example, as will be described later,
It is also used to connect the refrigerator oil filling device 22 and fill the refrigerator oil.

The accumulator 5 is for storing the liquid refrigerant that is liquefied on the low pressure side when the refrigerating operation is stopped, and particularly prevents the suction of the liquid refrigerant into the compressor at the start of the operation of the refrigeration system.

The method for filling the refrigerating machine oil and the refrigerant is carried out as follows according to the method in the conventional general refrigerating apparatus. The filling of the refrigerating machine oil in the factory is performed after the vacuum drying process of the refrigerating apparatus. First, the refrigerator oil filling device 22 is connected to the opening / closing valve 21 attached to the tip of the refrigerant filling branch pipe 20. Thereby, the refrigerator oil filling device 22 is connected to the inlet side point A of the outdoor heat exchanger 4. Refrigerator oil filling device 22
Is for supplying refrigerating machine oil into the refrigerant circuit by gas pressure using an appropriate gas, and by opening the on-off valve 21, a predetermined amount of refrigerating machine oil is filled into the refrigerant circuit from the refrigerating machine oil filling device 22. Is done. The filled refrigerating machine oil stays in the outdoor heat exchanger 4 or the like.

Next, the refrigerator oil filling device 22 is removed from the on-off valve 21, and the refrigerant tank 23 is connected to the on-off valve 21 instead. As a result, the refrigerant tank 23 is connected to the inlet side point A of the outdoor heat exchanger 4 via the opening / closing valve 21. Then, the on-off valve 21 is opened to supply a predetermined amount of refrigerant into the refrigerant circuit. At this time, the refrigerating machine oil accumulated in the outdoor heat exchanger 4 or the like is pumped into the hermetic housing of the two-stage compressor 1 by the pressure of the refrigerant with which the refrigerant circuit is filled. In addition to the general single-stage compressor, the above-described two-stage compressor 1 is
Refrigerating machine oil is stored in the bottom of a hermetically sealed housing of a compressor, and the refrigerating machine oil is pumped up by a simple pump mechanism and supplied to each sliding portion of the compression mechanism section. Therefore, it is necessary to store a sufficient amount of lubricating oil at the bottom of the closed housing at all times, especially when the compressor with a large lubricating load is started.

[0013]

[Problems to be Solved by the Invention] However, the above 2
In a staged compression refrigeration system, when trying to fill the refrigeration oil in the same manner as in the case of the general refrigeration system as described above,
It has been found that it is difficult to supply a sufficient amount of refrigerating machine oil to the bottom portion in the hermetically sealed housing of the two-stage compressor 1 because the flow resistance when passing through the low-stage compression mechanism portion is large.

The present invention has been made by paying attention to the problems existing in such a conventional technique, and in a two-stage compression refrigerating apparatus using a two-stage compressor, a compression mechanism portion having a large flow resistance is provided. It is an object of the present invention to fill a sufficient amount of refrigerating machine oil by filling the refrigerating machine oil into the closed housing of the two-stage compressor without passing through.

[0015]

In order to achieve the above object, the first solving means in the two-stage compression refrigerating apparatus according to the present invention is a low-stage compression mechanism part and a high-stage compression mechanism. In a two-stage compression type refrigeration system driven by a two-stage compressor having a portion housed in a hermetically sealed housing, the two-stage compressor seals the gas refrigerant discharged from the low-stage side compression mechanism portion of the two-stage compressor. It is formed so that the gas refrigerant discharged into the housing and discharged into the closed housing is guided to the suction port of the high-stage compression mechanism section, and communicates with the closed housing for connecting the refrigerating machine oil filling device. The refrigerating machine oil filling pipe is provided. According to this solution, since the refrigerator oil filling device is directly connected to the inside of the sealed housing of the two-stage compressor without passing through the compression mechanism portion having a large flow resistance, the refrigerator oil is supplied to the sealed housing of the two-stage compressor. It can be sufficiently supplied, and sufficient refrigerating machine oil can be stored in the bottom portion of the closed housing.

A second solving means in the two-stage compression refrigerating apparatus according to the present invention is a two-stage compressor having a low-stage compression mechanism section and a high-stage compression mechanism section housed in a hermetically sealed housing.
A two-stage compression refrigeration system comprising: an outdoor heat exchanger connected to a suction side of a compressor; and an accumulator connected between the outdoor heat exchanger and a suction side of a two-stage compressor. The stage compressor releases the gas refrigerant discharged from the low-stage compression mechanism portion into the closed housing of the two-stage compressor, and releases the gas refrigerant released into the closed housing into the suction port of the high-stage compression mechanism portion. A refrigerating machine oil filling pipe communicating with the inside of the hermetic housing for connecting the refrigerating machine oil filler, and further connecting a refrigerant tank to the inlet side pipe of the outdoor heat exchanger. It is provided with a branch pipe for charging the refrigerant. According to this solution, as in the case of the first solution described above, the refrigerator oil filling device is directly connected to the inside of the hermetically sealed housing of the two-stage compressor without passing through the compression mechanism section having large flow resistance. The refrigerating machine oil can be sufficiently supplied to the hermetic housing of the two-stage compressor, and sufficient refrigerating machine oil can be stored in the bottom portion of the hermetic housing. Furthermore, since the refrigerant can be filled from the refrigerant filling branch pipe provided on the inlet side of the outdoor heat exchanger, the liquid refrigerant among the filled refrigerant is easily stored in the outdoor heat exchanger and the accumulator, and the two-stage It is possible to reduce the amount of liquid back when starting the compressor.

A third solving means in the two-stage compression refrigerating apparatus according to the present invention is a two-stage compressor having a low-stage compression mechanism section and a high-stage compression mechanism section housed in a hermetically sealed housing,
An outdoor heat exchanger that exchanges heat with the heat source side fluid, a use side heat exchanger that exchanges heat with the fluid to be cooled, a four-way switching valve that reversibly switches the refrigerant circuit, and a four-way switching valve and the suction side of the compressor. In a two-stage compression refrigeration system including at least an accumulator connected between the two stages, the two-stage compressor discharges the gas refrigerant discharged from the low-stage compression mechanism portion into the hermetic housing of the two-stage compressor. Then, the refrigerating machine oil filling, which is formed so as to guide the gas refrigerant discharged into the closed housing to the suction port of the high-stage side compression mechanism part and communicates with the refrigerating machine oil filling device, is connected to the closed housing. And a refrigerant tank connected to the inlet side pipe of the outdoor heat exchanger in the refrigerant circuit in which the four-way switching valve is set to the switching position where the heat source side heat exchanger is on the suction side of the two-stage compressor. A branch pipe for refrigerant filling for Is Ete become one. According to this solving means, although it is a two-stage compression type refrigerating device capable of reversibly switching the refrigerant cycle, as in the case of the second solving means, it is sufficient for the bottom portion in the closed housing of the two-stage compressor. The refrigerating machine oil can be stored, and the liquid refrigerant among the refrigerant to be filled is easily stored in the outdoor heat exchanger and the accumulator, and the liquid back amount at the time of starting the two-stage compressor is alleviated.

The first solution to the refrigerating machine oil filling method according to the present invention is that in the two-stage compression refrigerating apparatus according to the first solving means, a refrigerating machine oil filling machine is connected to the refrigerating machine oil filling pipe. The refrigerating machine oil is filled into the hermetically sealed housing of the two-stage compressor through the refrigerating machine oil filling pipe. According to this solution, the refrigerating machine oil is supplied into the closed housing of the two-stage compressor without passing through the compression mechanism section having a large flow resistance. Can be stored.

A second solution in the refrigerating machine oil filling method according to the present invention is the two-stage compression refrigerating apparatus according to the second solving means, wherein a refrigerating machine oil filling device is connected to the refrigerating machine oil filling pipe. Then, the refrigerating machine oil is filled into the hermetic housing of the two-stage compressor through the refrigerating machine oil filling pipe, and then the refrigerant tank is connected to the refrigerant filling branch pipe, and the outdoor heat exchange is performed through the refrigerant filling branch pipe. The refrigerant is filled into the refrigerant circuit from the inlet side of the container. According to this solution, the refrigerating machine oil is filled before the pressure in the refrigerant circuit rises due to the refrigerant filling, so that the refrigerating machine oil can be easily filled. Further, since the refrigerating machine oil is supplied into the hermetically sealed housing of the two-stage compressor without passing through the compression mechanism section having a large flow resistance, sufficient refrigerating machine oil can be stored at the bottom of the hermetically sealed housing. Further, since the refrigerant can be filled from the inlet side of the outdoor heat exchanger, the liquid refrigerant of the refrigerant to be filled is easily stored in the outdoor heat exchanger and the accumulator, and the amount of liquid back at the start of the two-stage compressor is reduced. can do.

A third solution to the refrigerating machine oil filling method according to the present invention is the two-stage compression refrigerating apparatus according to the third solving means, wherein a refrigerating machine oil filling device is connected to the refrigerating machine oil filling pipe. Then, the refrigerating machine oil is filled into the hermetically sealed housing of the two-stage compressor through this refrigerating machine oil filling pipe, and then the refrigerant filling branch pipe is connected to the refrigerant tank, and the four-way switching valve is connected to the heat source side heat source. After the exchanger is set to the switching position on the suction side of the two-stage compressor, the refrigerant is filled into the refrigerant circuit from the inlet side of the outdoor heat exchanger via the refrigerant filling branch pipe. According to this solution, as in the second solution, the refrigerating machine oil is filled before the pressure in the refrigerant circuit rises due to the refrigerant filling, so that the refrigerating machine oil can be easily filled. Further, since the refrigerating machine oil is connected to the inside of the hermetically sealed housing of the two-stage compressor without passing through the compression mechanism section having a large flow resistance, sufficient refrigerating machine oil can be stored at the bottom of the hermetically sealed housing. Further, among the refrigerants to be filled, the liquid refrigerant is easily stored in the outdoor heat exchanger and the accumulator, and the liquid back amount at the time of starting the two-stage compressor is relaxed.

Further, in the above-mentioned solution means and solution, the two-stage compressor discharges the gas refrigerant discharged from the low-stage compression mechanism portion into the closed housing of the two-stage compressor,
The refrigerant gas discharged into the closed housing is formed so as to be guided to the suction port of the high-stage side compression mechanism portion by an external pipe arranged outside the closed housing, and the refrigerating machine oil filling pipe is connected to the external pipe. It may be constituted by a part and a refrigerating machine oil filling branch pipe branched from the external pipe. According to this structure, the refrigerating machine oil filling pipe is formed by utilizing a part of the external pipe, so that the refrigerating machine oil filling pipe can be easily formed.

The branching position of the refrigerating machine oil filling branch pipe in the external pipe is preferably at the same height as or higher than the position where the external pipe is connected to the closed housing. With this configuration, the refrigerating machine oil to be filled easily flows into the hermetically sealed housing of the two-stage compressor due to gravity, and the amount of refrigerating machine oil stored in the hermetically sealed housing increases. Therefore, it becomes easy to supply the lubricating oil to the sliding portion when the compressor is started.

Further, in the above-mentioned solution means and solution, the two-stage compressor discharges the gas refrigerant discharged from the low-stage compression mechanism portion into the closed housing of the two-stage compressor,
The gas refrigerant discharged into the closed housing is formed so as to be guided directly from the closed housing to the suction port of the high-stage compression mechanism portion, and the refrigerating machine oil filling pipe communicates the inside and outside of the closed housing. It may be configured by a refrigerating machine oil filling conduit led out from the closed housing. According to this structure, the refrigerator oil filling pipe is directly provided in the closed housing of the two-stage compressor,
It becomes possible to reliably fill the refrigeration oil with or without external piping.

Further, in the above-mentioned solving means and solving method, an opening / closing valve may be attached to the refrigerating machine oil filling pipe. According to this structure, when refilling the refrigerating machine oil, the filling operation such as connecting the refrigerating machine oil filling device to the refrigerating machine oil filling branch pipe becomes easy.

Further, in the above-mentioned solution means and solution, in the two-stage compression refrigeration system, the discharge gas temperature is HCF.
Alternative CFCs such as HFC32, a mixed refrigerant containing HFC32, or a natural refrigerant such as carbon dioxide or ammonia, which has a temperature higher than that of C22, may be used as a refrigerant and operated in a supercritical refrigeration cycle. In the case of a refrigeration apparatus that operates in a supercritical refrigeration cycle using such a refrigerant, the diameter of the heat exchange tube of the outdoor heat exchanger is often made thin and the volume of the accumulator is also made large. Further, in such a refrigerating apparatus, refrigerating machine oil is less likely to be introduced into the hermetically sealed housing of the compressor as compared with a general refrigerating apparatus. However, if configured as described above, regardless of whether the refrigeration cycle is a supercritical cycle,
Further, regardless of the type of refrigerant, the refrigerating machine oil can be sufficiently stored in the hermetically sealed housing of the two-stage compressor.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. Hereinafter, the first embodiment of the present invention will be described with reference to FIGS. 1 and 2.
1 is a circuit diagram for explaining a method of filling refrigerating machine oil and refrigerant in a two-stage compression refrigerating apparatus according to Embodiment 1 of the present invention, and FIG. FIG. In these figures, the same elements as those of the conventional one shown in FIG.
The explanation will be simplified.

The refrigerant circuit of the two-stage compression refrigerating apparatus shown in FIG. 1 has an expansion device such as the two-stage compressor 1, the water heat exchanger 2, the electric expansion valve, etc., as in the conventional one described in FIG. 3, an outdoor heat exchanger 4, and an accumulator 5 are sequentially connected. Also, the discharge gas temperature in this refrigerant circuit is HCFC2.
HFC32 that is higher than 2 or an alternative CFC such as a mixed refrigerant containing HFC32 or a natural refrigerant such as carbon dioxide or ammonia is filled, and this two-stage compression refrigeration system is refrigerated by a supercritical refrigeration cycle. There is. Further, a hot water storage tank 7 is connected to the water heat exchanger 2, and hot water for hot water stored in the water heat exchanger 2 is stored therein.

A refrigerant filling branch pipe 20 for connecting a refrigerant tank 23 is provided on the inlet side of the outdoor heat exchanger 4. The refrigerant filling branch pipe 20 is a pipe having a small diameter connected to a point A of the inlet side pipe of the outdoor heat exchanger 4. An on-off valve (service valve) 21 is attached to the tip of the branch pipe 20 for charging the refrigerant. Unlike the conventional one, the refrigerator oil filling device 22 is not connected to the refrigerant filling branch pipe 20.

The two-stage compressor 1 has a low-stage compression mechanism 11 and a high-stage compression mechanism 12 housed inside a hermetically sealed housing. Then, the discharge gas (gas refrigerant having an intermediate pressure) from the low-stage compression mechanism portion 11 is once released into the closed housing, and the released intermediate-pressure gas refrigerant is passed through the external pipe 6 to the high-stage compression mechanism. Inhaled into the part 12.

The external pipe 6 of the two-stage compressor 1 is provided with a refrigerating machine oil filling branch pipe 25 for connecting the refrigerating machine oil filling device 22. The branch pipe 25 for filling the refrigerating machine oil is
A small diameter pipe is connected to an appropriate point (point B) of the external pipe 6, and an opening / closing valve (service valve) 26 is attached to the tip of the branch pipe 25 for filling the refrigerating machine oil.
The connection position B of the branch pipe 25 for filling the refrigerating machine oil in the external pipe 6 is in the vicinity of the connection position C for connecting the external pipe 6 into the sealed housing of the two-stage compressor 1, and this connection position C
It is preferable that the position is the same as or higher than
So configured. The refrigerating machine oil filling pipe is composed of the refrigerating machine oil filling branch pipe 25 and a part of the external pipe 6 connected from the point B to the point C of the hermetic housing.

In the two-stage compression type refrigerating apparatus constructed as described above, the refrigerating machine oil and the refrigerant are charged as follows. When the refrigerant is filled in the refrigerating apparatus, the pressure in the refrigerant circuit becomes high and it becomes difficult to put the refrigerating machine oil. Therefore, the refrigerating machine oil is first filled. When filling the refrigerating machine oil, the refrigerating machine oil filling device 22 is connected to the opening / closing valve 26 attached to the refrigerating machine oil filling branch pipe 25 of the external pipe 6 of the two-stage compressor 1. Thereby, the refrigerator oil filling device 22 is connected to the external pipe 6 at the point B via the opening / closing valve 26, and the two-stage compressor 1 is connected via the opening / closing valve 26, the refrigerator oil filling branch pipe 25 and the external pipe 6. Connected in the housing. Here, the on-off valve 26 is opened and a predetermined amount of refrigerating machine oil is filled.

Next, the on-off valve 26 is closed and the refrigerator oil filling device 22 is removed from the on-off valve 26. On the other hand, the refrigerant tank 23 is connected to the opening / closing valve 21 provided in the refrigerant filling branch pipe 20 on the inlet side of the outdoor heat exchanger 4. As a result, the refrigerant tank 23 is connected to the inlet side point A of the outdoor heat exchanger 4 via the on-off valve 21 and the refrigerant charging branch pipe 20. And
The on-off valve 21 is opened to supply a predetermined amount of refrigerant into the refrigerant circuit. After the completion of charging the refrigerant, the on-off valve 21 is closed.

After the on-off valves 21 and 25 are filled with the refrigerating machine oil and the refrigerant, they may be left as they are so that they can be reused for additional filling. Also, this on-off valve 21,
25 may be removed so that it can be reused for filling refrigerating machine oil and refrigerant in another refrigerating apparatus. However, in the latter case, it is necessary to pinch and braze the ends of the refrigerator oil filling branch pipe 25 and the refrigerant filling branch pipe for sealing.

The refrigerating machine oil filled in the two-stage compressor 1 as described above is stored in the closed housing of the two-stage compressor 1. The stored refrigerating machine oil is supplied to the motor 1
5 is pumped up by the oil pump mechanism 16 driven by the rotation of the compressor 5, and the compression mechanism parts 11, 1 are passed through the oil passage 17.
It is supplied to each of the two sliding parts (see FIG. 2).

In the first embodiment, the refrigerating machine oil and the refrigerant are filled by the above-mentioned method, so that the following effects can be obtained. Since the refrigerating machine oil is filled into the refrigerant circuit in a vacuum or low pressure state before being filled with the refrigerant, the refrigerating machine oil can be easily filled. The refrigerator oil filler 22 is directly connected to the inside of the hermetic housing of the two-stage compressor 1 (in the first embodiment, the refrigerator oil filler pipe is part of the external pipe 6 and the refrigerator oil). Since it is connected to the filling branch pipe 25), the refrigerating machine oil pushed out from the refrigerating machine oil filling device 22 does not stay in the outdoor heat exchanger 4 or the accumulator 5 on the compressor suction side, and It is directly introduced into the hermetic housing of the two-stage compressor 1 without passing through the devices having large flow resistance such as the devices 4, 5 and the low-stage compression mechanism section 11. Therefore, the refrigerating machine oil is sufficiently filled in the hermetically sealed housing of the two-stage compressor 1, and it is possible to sufficiently supply the lubricating oil to the sliding parts of the respective compression mechanism parts. Further, the branch pipe 2 for filling the refrigerating machine oil in the external pipe 6
Since the connection position B point of 5 has a height equal to or higher than the connection position C point where the external pipe is connected to the closed housing of the two-stage compressor 1, the refrigerating machine oil is filled when the refrigerating machine oil is filled. Refrigerating machine oil extruded from the filler 22 to the external pipe 6 easily flows into the closed housing of the two-stage compressor 1. In addition, it is easy to provide the branch pipe 25 for filling the refrigerator oil in the external pipe 6. On the other hand, since the refrigerant is introduced from the refrigerant filling branch pipe 20 on the inlet side of the outdoor heat exchanger 4, the refrigerant is introduced into the outdoor heat exchanger 4 before reaching the low-stage compression mechanism portion 11 of the two-stage compressor 1. The introduced refrigerant, especially a liquid refrigerant (liquid refrigerant), is stored in the outdoor heat exchanger 4 and the accumulator 5. Therefore, 2
When the stage compressor 1 is started, the amount of liquid refrigerant sucked into the low stage side compression mechanism portion 11 is relaxed. Further, as in the two-stage compression refrigeration system in this embodiment, HFC32 having a discharge gas temperature higher than that of the HCFC22, alternative CFCs such as a mixed refrigerant containing HFC32, or a natural refrigerant such as carbon dioxide or ammonia is used as the refrigerant. In the refrigerating apparatus which is used as the above and operates in the supercritical refrigerating cycle, the pipe diameter of the heat exchange tube of the outdoor heat exchanger 4 is usually thin, and the volume of the accumulator 5 is also large. Therefore, when refrigerating machine oil is introduced from the inlet side of the outdoor heat exchanger 4 as in the conventional case, the resistance of the path to the hermetically sealed housing of the two-stage compressor 1 becomes particularly large, and the refrigerating machine oil is stored in the hermetically sealed housing. There was a problem that it was difficult.
However, as in this embodiment, the refrigerator oil filling device 22
Is connected to the closed housing of the two-stage compressor 1 without a large resistance through the refrigerating machine oil filling branch pipe 25 and the external pipe 6 to solve such a problem. Refrigerant filling branch pipe 20 and refrigerating machine oil filling branch pipe 2
When the on-off valves 21 and 26 of 5 are left without being removed after the refrigerant and the refrigerating machine oil are filled, it is easy to connect the refrigerant tank 23 and the refrigerating machine oil filling device 22 to refill the refrigerant and the refrigerating machine oil. Become.

Embodiment 2. Next, a second embodiment will be described based on FIG. Note that FIG. 3 is a circuit diagram for explaining a method of filling the refrigerating machine oil and the refrigerant in the two-stage compression refrigerating apparatus according to the second embodiment. The same elements as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the second embodiment, the present invention is embodied in a heat pump type two-stage compression type refrigerating apparatus (for example, a heat pump type air conditioner) which reversibly switches the refrigerant circuit. More specifically, this heat pump type refrigeration system is separated into an outdoor unit 30a and an indoor unit 30b, as shown in FIG. Outdoor unit 30a
Inside, at least a two-stage compressor 1, a four-way switching valve 31, an outdoor heat exchanger (heat source side heat exchanger) 34, an accumulator 35, and an expansion device 33 such as an electric expansion valve are mounted.
Further, the indoor unit 30b has at least an indoor heat exchanger (use side heat exchanger) 32 mounted therein. And both 30a, 30b are connected by the connection refrigerant piping 36, 37, and comprise the refrigerant circuit. The refrigerant circuit is filled with a general refrigerant such as HCFC22.

This refrigerant circuit is switched by a four-way switching valve 31, a two-stage compressor 1, a four-way switching valve 31, an outdoor heat exchanger 34, an expansion device 33, an indoor heat exchanger 32, a four-way switching valve 31. → accumulator 35 → cooling operation cycle for circulating the refrigerant with the two-stage compressor 1 and the two-stage compressor 1 → four-way switching valve 31 → indoor heat exchanger 32 → expansion device 33 → outdoor heat exchanger 34 → four-way switching The valve 31 → the accumulator 35 → the two-stage compressor 1 and the heating operation cycle in which the refrigerant is circulated are switched to perform the cooling or heating operation as appropriate.

The outdoor heat exchanger (heat source side heat exchanger)
The refrigerant tank 2 is provided on the inlet side of the heating cycle of No. 34.
A branch pipe 20 for charging the refrigerant for connecting the three is provided. The refrigerant filling branch pipe 20 has a small diameter pipe connected to a point A of the (heat source side heat exchanger) inlet side pipe of the outdoor heat exchanger 34. An on-off valve (service valve) 21 is attached to the tip of the branch pipe 20 for charging the refrigerant. As in the case of the first embodiment, refrigerating machine oil filling device 22 is not connected to this refrigerant filling branch pipe 20.

The two-stage compressor 1 is the same as that of the first embodiment. That is, the external pipe 6 of the two-stage compressor 1
A refrigerating machine oil filling branch pipe 25 for connecting the refrigerating machine oil filling device 22 is provided. The refrigerating machine oil filling branch pipe 25 is a pipe having a small diameter connected to an appropriate point (point B) of the external pipe 6. An on-off valve (service valve) 26 is attached to the tip of the refrigerator oil filling branch pipe 25. The connection position B of the refrigerator oil filling branch pipe 25 to the external pipe 6 is in the vicinity of the connection position C for connecting the external pipe 6 to the sealed housing of the two-stage compressor 1,
A position that is the same as or higher than this connection position C is preferable, and is configured as such. The refrigerating machine oil filling pipe according to the first embodiment is similar to the case of the first embodiment with the refrigerating machine oil filling branch pipe 25 and a part of the external pipe 6 connected from the point B to the point C of the closed housing. Composed of.

In the two-stage compression type refrigerating apparatus thus constructed, the refrigerating machine oil and the refrigerant are charged as follows. First, the four-way switching valve 31 is set in the heating operation cycle state without operating the compressor, and the refrigerant circuit is set as the heating operation cycle circuit. Then, the refrigerating machine oil and the refrigerant are filled in the same manner as in the first embodiment. That is, the refrigerator oil is filled before the refrigerant is filled. In filling the refrigerating machine oil, the refrigerating machine oil filling device 22 is connected to the opening / closing valve 26 attached to the refrigerating machine oil filling branch pipe 25 of the external pipe 6 of the two-stage compressor 1. Thereby, the refrigerator oil filling device 22 is connected to the external pipe 6 at the point B via the opening / closing valve 26, and is connected to the inside of the hermetic housing of the two-stage compressor 1 via the external pipe 6. Here, the on-off valve 26 is opened and a predetermined amount of refrigerating machine oil is filled.

Next, the on-off valve 26 is closed and the refrigerator oil filling device 22 is removed from the on-off valve 26. On the other hand, the refrigerant tank 23 is connected to the opening / closing valve 21 provided in the refrigerant filling branch pipe 20 on the inlet side of the outdoor heat exchanger 34. Thereby, the refrigerant tank 23 is connected to the inlet side point C of the outdoor heat exchanger 4 via the opening / closing valve 21. Then, the on-off valve 21 is opened to supply a predetermined amount of refrigerant into the refrigerant circuit. After the refrigerant is filled,
The on-off valve 21 is closed.

In the second embodiment, as described above, the refrigerating machine oil and the refrigerant are filled by the same method as in the first embodiment. Therefore, also in the heat pump type refrigerating apparatus, the same as in the first embodiment. It is possible to achieve various effects.

Embodiment 3. Embodiment 2. Next, a third embodiment will be described based on FIG. 4. FIG. 4 is a circuit diagram for explaining the method of filling the refrigerating machine oil and the refrigerant in the two-stage compression refrigerating apparatus according to the third embodiment. The same elements as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

The third embodiment is the same as the second embodiment.
The configuration of the stage compressor 1 and the configuration of the refrigerator oil filling pipe are changed. The two-stage compressor 1 does not have the external pipe 6 as in the first embodiment. That is, as in the first embodiment, the low-stage compression mechanism 11 and the high-stage compression mechanism 12 are housed inside the sealed housing. However, unlike the first embodiment, the discharge gas (gas refrigerant having an intermediate pressure) from the low-stage compression mechanism portion 11 is once discharged into the sealed housing, and then directly in the sealed housing inside the high-stage side. The compression mechanism 12 is formed so as to be guided to the suction port, and the external pipe 6 as in the first embodiment.
Not equipped. Further, as a refrigerator oil filling pipe, a refrigerator oil filling conduit 28 is led out from the side wall of the sealed housing so as to communicate the inside and outside of the sealed housing. An on-off valve 26 is provided in the refrigerator oil filling conduit 28.

In the method for filling the refrigerating machine oil according to the third embodiment, the refrigerating machine oil filling device 22 is connected to the refrigerating machine oil filling conduit 28.
It is the same as the case of the embodiment except that it is connected to the on-off valve 26 attached to. The charging of the refrigerant is also the same as in the first embodiment.

Therefore, according to the third embodiment, the same effect as that of the first embodiment can be obtained. Further, as in the third embodiment, the refrigerator oil filling conduit 28 is used.
When is directly provided in the closed housing of the two-stage compressor, the refrigerating machine oil can be reliably filled regardless of the presence or absence of external piping.

[0048]

Since the present invention is constructed as described above, it has the following effects. Since the refrigerating machine oil is connected to the closed housing of the two-stage compressor without passing through the compression mechanism section having a large flow resistance, the refrigerating machine oil does not stay in the outdoor heat exchanger or accumulator on the suction side of the compressor. It can be introduced into the closed housing of the two-stage compressor, and sufficient refrigerating machine oil can be stored in the closed housing.

Further, if a refrigerant filling branch pipe for connecting a refrigerant tank is provided in the inlet side pipe of the outdoor heat exchanger, and if the refrigerant can be filled from this refrigerant filling branch pipe, Among them, the liquid refrigerant is easily stored in the outdoor heat exchanger and the accumulator, and the amount of the liquid refrigerant sucked into the compressor at the time of starting the two-stage compressor can be reduced.

When the refrigerating machine oil filling pipe is composed of a part of the external pipe and a refrigerating machine oil filling branch pipe branched from the external pipe, the refrigerating machine oil filling pipe is easily formed. can do. Further, if the branching position of the refrigerating machine oil filling branch pipe in this external pipe has a height equal to or higher than the position where this external pipe is connected to the hermetic housing, the refrigerating machine oil to be filled will be gravitated by gravity. The two-stage compressor can easily flow into the closed housing, and the amount of refrigerating machine oil stored in the closed housing increases. Therefore, it becomes easy to supply the lubricating oil to the sliding portion when the compressor is started.

Further, if the refrigerating machine oil filling pipe is constituted by the refrigerating machine oil filling conduit led out from the closed housing so as to communicate the inside and outside of the closed housing, the refrigerating machine oil filling pipe becomes a closed housing of the two-stage compressor. Since it is directly provided, the refrigerating machine oil can be reliably filled regardless of the presence or absence of external piping.

Further, if an opening / closing valve is provided in the refrigerating machine oil filling pipe, when refilling the refrigerating machine oil, the filling operation such as connecting the refrigerating machine oil filling device to the refrigerating machine oil filling branch pipe can be easily performed. You can

As the refrigerant, the discharge gas temperature is HCF.
The diameter of the heat exchange tube of the outdoor heat exchanger is reduced, as seen when using HFC32 that is higher than C22, alternative CFCs such as mixed refrigerants containing HFC32, or natural refrigerants such as carbon dioxide and ammonia. Even in the case of increasing the capacity of the accumulator, the refrigerating machine oil can be sufficiently stored in the closed housing of the two-stage compressor.

[Brief description of drawings]

FIG. 1 is a circuit diagram for explaining a method of filling refrigerating machine oil and refrigerant in a two-stage compression refrigerating apparatus according to Embodiment 1 of the present invention.

FIG. 2 is an enlarged view around the two-stage compressor in FIG.

FIG. 3 is a circuit diagram for explaining a method of filling refrigerating machine oil and refrigerant in a two-stage compression refrigerating apparatus according to a second embodiment.

FIG. 4 is a circuit diagram for explaining a method of filling refrigerating machine oil and refrigerant in a two-stage compression refrigerating apparatus according to a third embodiment.

FIG. 5 is a circuit diagram for explaining a method of filling refrigerating machine oil and refrigerant in a conventional two-stage compression refrigerating apparatus.

[Explanation of symbols]

1 and 2 stage compressor 2 Water heat exchanger 3 expansion device 4 outdoor heat exchanger 5 Accumulator 6 External piping 11 Low-stage compression mechanism 12 High-stage compression mechanism 20 Branch pipe for refrigerant filling 21 on-off valve 22 Refrigerator oil filling device 23 Refrigerant tank 25 Refrigerator oil filling branch pipe 26 on-off valve 28 Refrigerator oil filling conduit

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shigeo             1 Otsuki-cho, Ashikaga City, Tochigi Prefecture Sanyo Electric Air Conditioning             Within the corporation (72) Inventor Satoshi Hoshino             1 Otsuki-cho, Ashikaga City, Tochigi Prefecture Sanyo Electric Air Conditioning             Within the corporation (72) Inventor Kiyoshi Koyama             1 Otsuki-cho, Ashikaga City, Tochigi Prefecture Sanyo Electric Air Conditioning             Within the corporation (72) Inventor Sadahiro Takizawa             1 Otsuki-cho, Ashikaga City, Tochigi Prefecture Sanyo Electric Air Conditioning             Within the corporation (72) Inventor Chiaki Shichiji             1 Otsuki-cho, Ashikaga City, Tochigi Prefecture Sanyo Electric Air Conditioning             Within the corporation (72) Inventor Shigaya Ishigaki             1 Otsuki-cho, Ashikaga City, Tochigi Prefecture Sanyo Electric Air Conditioning             Within the corporation F-term (reference) 3H003 AB04 AC03 BD03 CD07                 3H029 AB03 AB08 BB10 BB34 CC32

Claims (21)

[Claims] 1. A two-stage compression refrigeration apparatus driven by a two-stage compressor in which a low-stage compression mechanism part and a high-stage compression mechanism part are housed in a hermetically sealed housing, wherein the two-stage compressor is a low-stage compressor. The gas refrigerant discharged from the side compression mechanism portion is discharged into the closed housing of the two-stage compressor, and the gas refrigerant discharged into the closed housing is formed to be guided to the suction port of the high-stage compression mechanism portion. A two-stage compression type refrigerating apparatus comprising a refrigerator oil filling pipe communicating with the inside of a hermetic housing for connecting the refrigerator oil filling device. 2. A two-stage compressor having a low-stage compression mechanism part and a high-stage compression mechanism part housed in a hermetically sealed housing, an outdoor heat exchanger connected to a suction side of the compressor, and the outdoor heat exchanger. In a two-stage compression refrigeration system including a compressor and an accumulator connected between the suction side of the two-stage compressor, the two-stage compressor includes a gas refrigerant discharged from a low-stage side compression mechanism part It is formed so as to be discharged into the closed housing of the stage compressor and guide the gas refrigerant discharged into the closed housing to the suction port of the high-stage compression mechanism section, and for connecting the refrigerator oil filling device, A two-stage compression type refrigerating apparatus comprising a refrigerating machine oil filling pipe communicating with the inside of a closed housing, and further comprising a refrigerant filling branch pipe for connecting a refrigerant tank to an inlet side pipe of the outdoor heat exchanger. 3. A two-stage compressor having a low-stage compression mechanism section and a high-stage compression mechanism section housed in a hermetically sealed housing, an outdoor heat exchanger for exchanging heat with a heat source side fluid, and heat exchange with a fluid to be cooled. A two-stage compression refrigerating apparatus including at least a utilization side heat exchanger, a four-way switching valve for reversibly switching a refrigerant circuit, and an accumulator connected between the four-way switching valve and a suction side of a compressor. The two-stage compressor discharges the gas refrigerant discharged from the low-stage compression mechanism portion into the closed housing of the two-stage compressor, and releases the gas refrigerant discharged into the closed housing into the high-stage compression mechanism portion. A refrigerating machine oil filling pipe connected to the inside of the closed housing for connecting the refrigerating machine oil filling device, the four way switching valve being a heat source side heat exchanger. The switching position was set to the suction side of the two-stage compressor. 2-stage compression refrigeration device including a refrigerant charging branch pipe for connecting the refrigerant tank to the inlet side pipe of the outdoor heat exchanger in the medium circuit. 4. The two-stage compressor discharges the gas refrigerant discharged from the low-stage side compression mechanism portion into a sealed housing of the two-stage compressor, and the gas refrigerant discharged into the sealed housing is sealed housing. The refrigerating machine oil filling pipe is formed so as to be guided to the suction port of the high-stage side compression mechanism section by an external pipe arranged outside, and the refrigerating machine oil filling pipe is a part of the external pipe and a refrigerating machine oil filling branched from the external pipe. A two-stage compression refrigeration system according to any one of claims 1 to 3, wherein the two-stage compression refrigeration system is constituted by a branch pipe for use. 5. The two-stage compressor discharges the gas refrigerant discharged from the low-stage side compression mechanism portion into a sealed housing of the two-stage compressor, and seals the gas refrigerant discharged into the sealed housing. The refrigerating machine oil filling pipe is formed so as to be guided directly from the inside of the housing to the suction port of the high-stage side compression mechanism section, and the refrigerating machine oil filling pipe is constituted by a refrigerating machine oil filling conduit drawn from the closed housing so as to communicate the inside and outside of the closed housing. Any one of claims 1 to 3
The two-stage compression type refrigerating apparatus according to the item. 6. The branch position of the refrigerating machine oil filling branch pipe in the external pipe has a height equal to or higher than a position where the external pipe is connected to the hermetically sealed housing. Stage compression refrigeration system. 7. The two-stage compression type refrigerating apparatus according to claim 1, wherein an opening / closing valve is attached to the refrigerating machine oil filling pipe. 8. A CFC substitute, such as HFC32 or a mixed refrigerant containing HFC32, whose discharge gas temperature is higher than that of the HCFC22, or a natural refrigerant such as carbon dioxide or ammonia is used as a refrigerant and is operated in a supercritical refrigeration cycle. The two-stage compression refrigeration system according to any one of claims 1 to 8. 9. The two-stage compression refrigerating apparatus according to claim 1, wherein a refrigerator oil filler is connected to the refrigerator oil filling pipe, and the refrigerator oil is hermetically sealed in the two-stage compressor via the refrigerator oil filling pipe. A method for filling refrigerating machine oil in a two-stage compression refrigerating apparatus, which is configured to fill the housing. 10. The two-stage compressor discharges the gas refrigerant discharged from the low-stage compression mechanism portion into a hermetically sealed housing of the two-stage compressor, and the gas refrigerant discharged into the hermetically sealed housing is a hermetically sealed housing. The refrigerating machine oil filling pipe is formed so as to be guided to the suction port of the high-stage side compression mechanism section by an external pipe arranged outside, and the refrigerating machine oil filling pipe is a part of the external pipe and a refrigerating machine oil filling branched from the external pipe. A refrigerating machine oil filling method in a two-stage compression refrigerating apparatus according to claim 9, wherein the refrigerating machine oil is filled with a branch pipe. 11. The two-stage compressor discharges the gas refrigerant discharged from the low-stage side compression mechanism portion into a sealed housing of the two-stage compressor, and seals the gas refrigerant discharged into the sealed housing. The refrigerating machine oil filling pipe is formed so as to be guided directly from the inside of the housing to the suction port of the high-stage side compression mechanism section, and the refrigerating machine oil filling pipe is constituted by a refrigerating machine oil filling conduit drawn from the closed housing so as to communicate the inside and outside of the closed housing. A method of filling refrigerating machine oil in a two-stage compression refrigerating apparatus according to claim 9. 12. The connection position of the refrigerating machine oil filling branch pipe in the external pipe is the same height as or higher than the position where the external pipe is connected to the closed housing, A method for filling refrigerating machine oil in a stage compression refrigerating apparatus. 13. An on-off valve is attached to the refrigerating machine oil filling pipe, and a refrigerating machine oil filling device is connected to the refrigerating machine oil filling pipe via the on-off valve, and the on-off valve is opened to open the refrigerating machine oil. The method for filling refrigerating machine oil in the two-stage compression refrigerating apparatus according to any one of claims 9 to 12, wherein the refrigerating machine oil is filled. 14. The two-stage compression type refrigerating apparatus has HFC32, HFC whose discharge gas temperature is higher than that of HCFC22.
Alternative CFCs such as mixed refrigerants containing 32, or natural refrigerants such as carbon dioxide and ammonia are used as refrigerants,
It is operated by a supercritical refrigeration cycle.
14. A method for filling refrigerating machine oil in the two-stage compression refrigerating apparatus according to any one of 13 above. 15. The two-stage compression refrigerating apparatus according to claim 2, wherein a refrigerator oil filler is connected to the refrigerator oil filling pipe, and the refrigerator oil is hermetically sealed in the two-stage compressor through the refrigerator oil filling pipe. A two-stage compression in which the inside of the housing is filled, and then a refrigerant tank is connected to the refrigerant filling branch pipe, and the refrigerant circuit is filled from the inlet side of the outdoor heat exchanger through the refrigerant filling branch pipe. Method for filling refrigerating machine oil and refrigerant in a refrigeration system. 16. The two-stage compression refrigerating apparatus according to claim 3, wherein a refrigerator oil filler is connected to the refrigerator oil filling pipe, and the refrigerator oil is sealed in the two-stage compressor via the refrigerator oil filling pipe. After filling the housing, a refrigerant tank is connected to the refrigerant filling branch pipe, and the four-way switching valve is set to a switching position where the heat source side heat exchanger is on the suction side of the two-stage compressor, A method for filling refrigerating machine oil and a refrigerant in a two-stage compression refrigerating device, wherein a refrigerant is filled into a refrigerant circuit from an inlet side of an outdoor heat exchanger via a filling branch pipe. 17. The two-stage compressor discharges the gas refrigerant discharged from the low-stage side compression mechanism portion into a hermetically sealed housing of the two-stage compressor, and the gas refrigerant discharged into the hermetically sealed housing is a hermetically sealed housing. The refrigerating machine oil filling pipe is formed so as to be guided to the suction port of the high-stage side compression mechanism section by an external pipe arranged outside, and the refrigerating machine oil filling pipe is a part of the external pipe and a refrigerating machine oil filling branched from the external pipe. 17. A method of filling refrigerating machine oil and a refrigerant in a two-stage compression refrigerating apparatus according to claim 15 or 16, which is configured by a branch pipe for use. 18. The two-stage compressor discharges the gas refrigerant discharged from the low-stage side compression mechanism portion into a sealed housing of the two-stage compressor, and seals the gas refrigerant discharged into the sealed housing. The refrigerating machine oil filling pipe is formed so as to be guided directly from the inside of the housing to the suction port of the high-stage side compression mechanism section, and the refrigerating machine oil filling pipe is constituted by a refrigerating machine oil filling conduit drawn from the closed housing so as to communicate the inside and outside of the closed housing. A method of filling refrigerating machine oil and refrigerant in a two-stage compression refrigerating apparatus according to claim 15 or 16. 19. The connection position of the branch pipe for filling the refrigerating machine oil in the external pipe has a height equal to or higher than a position where the external pipe is connected to the hermetically sealed housing or a height higher than that. A method for filling refrigerating machine oil and a refrigerant in a stage compression refrigerating apparatus. 20. An opening / closing valve is attached to the refrigerating machine oil filling pipe, and the refrigerating machine oil filling device is connected to the refrigerating machine oil filling pipe via the opening / closing valve.
20. A method of filling refrigerating machine oil and refrigerant in the two-stage compression refrigerating apparatus according to any one of 19 above. 21. In the two-stage compression refrigeration system, the discharge gas temperature is higher than that of the HCFC22.
Alternative CFCs such as mixed refrigerants containing 32, or natural refrigerants such as carbon dioxide and ammonia are used as refrigerants,
The refrigerating machine oil and refrigerant filling method in a two-stage compression refrigerating apparatus according to any one of claims 15 to 20, which is operated in a supercritical refrigeration cycle.