JP2010084954A - Refrigerating cycle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an increase of a high pressure-side pressure loss caused by the existence of an oil separator, and to quickly supply an excess lubricant to a compressor shell according to necessity. <P>SOLUTION: This refrigerating cycle device includes a closed circuit constituted by successively connecting a sealed compressor 5 including a compressing mechanism 54 and a driving mechanism in the same shell 51, a condenser, a pressure reducing means 8, and an evaporator by refrigerant piping, and the lubricant is circulated in the closed circuit with a refrigerant. The refrigerating cycle device further includes an oil storage container 10 capable of storing the lubricant. The oil storage container has connecting ports 10a, 10b at its top and bottom in the vertical direction, the connecting port 10a of the top is connected with low-pressure piping between the evaporator and the compressor, and the connecting port 10b of the bottom is connected with high-pressure piping of the compressor through an opening/closing means. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention includes a vapor compression refrigeration cycle apparatus, in particular, a compressor in which a compression mechanism and a drive mechanism are sealed in the same container, and further stores lubricating oil in the container to lubricate the sliding portion. The present invention relates to a refrigeration cycle apparatus.

  In general, in this type of refrigeration cycle apparatus, part of the lubricating oil stored in the compressor is always discharged out of the compressor together with the refrigerant, and circulates in the refrigeration cycle. At this time, if the lubricating oil stays in the refrigeration cycle and it becomes difficult to return to the compressor, the lubricating oil surface in the compressor may be lowered and cause a failure. In order to prevent this, a relatively large amount of lubricating oil is enclosed in the refrigeration cycle apparatus.

  In a hermetic compressor in which the compression mechanism and the drive mechanism are in the same container (hereinafter referred to as “shell”), a lubricating oil surface is formed on the bottom of the shell, and lubrication is provided by providing an oil supply mechanism that supplies the lubricant to the compression mechanism. However, if too much lubricating oil is present in the shell, it will come into contact with the rotating part of the drive mechanism, increasing the rotational resistance, and the oil discharge rate will increase due to the stirring of the lubricating oil. There was a case.

  In order to avoid such a problem, an oil outflow hole is provided at a predetermined height position of the compressor shell so that the oil surface does not come into contact with the rotating portion, and excess oil merged with the discharged refrigerant is removed from the oil separator. There is known one that is returned to the compressor suction side via (see, for example, Patent Document 1).

Japanese Patent Laying-Open No. 2005-282946 (FIG. 1)

  Thus, the hermetic compressor requires an oil separator for preventing a large amount of lubricating oil discharged outside the shell from being circulated to the refrigeration cycle side. Conventionally, this oil separator is connected to a high-pressure pipe of a compressor, and oil mixed in the discharged refrigerant is separated using gravity or centrifugal force. For this reason, there was a problem that a considerable pressure loss was caused and the burden on the compressor was increased.

  In addition, when the operation mode in which the lubricating oil in the shell is minimized, the excess lubricating oil that is widely distributed and circulated in the discharge pipe (high-pressure pipe), oil separator, and suction pipe (low-pressure pipe) is required. There is a problem that it is not easy to quickly return to the shell according to the situation.

  The technical problem of the present invention is to avoid an increase in high-pressure pressure loss due to the presence of an oil separator, and to allow surplus lubricating oil to be quickly supplied to the compressor shell as necessary.

  The refrigeration cycle apparatus according to the present invention has the following configuration. That is, a closed type compressor provided with a compression mechanism and a drive mechanism in the same shell, a condenser, a decompression means, and an evaporator are connected in series by a refrigerant pipe to form a closed circuit. A refrigeration cycle apparatus in which lubricating oil circulates in a circuit together with a refrigerant, comprising an oil storage container capable of storing the lubricating oil, the oil storage container having a connection port at each of a vertical top part and a bottom part, and a top part The connection port is connected to a low-pressure pipe between the evaporator and the compressor, and the connection port at the bottom is connected to the high-pressure pipe of the compressor through an opening / closing means.

  According to the refrigeration cycle apparatus of the present invention, during cooling or heating operation, surplus lubricating oil that stays in the compressor shell and deteriorates the operation efficiency is removed, and oil whose top connection port is connected to the low-pressure side intake pipe. Since it is stored in the storage container, it causes the efficiency loss such as the pressure loss required for oil separation when connecting a conventional oil separator to the high-pressure piping of the compressor and the refrigerant bypass that occurs with oil return. Therefore, highly efficient operation can be performed.

  Also, in modes where there is a shortage of lubricating oil in the compressor shell, such as when heating is started, high pressure is introduced into the oil storage container from the connection port at the bottom by opening the opening and closing means, and the suction pipe from the connection port at the top Oil can be discharged into (low pressure piping). For this reason, the amount of oil in the shell can be quickly recovered.

  FIG. 1 is a refrigerant circuit diagram showing a refrigeration cycle apparatus according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view showing the internal structure of the hermetic compressor, and FIG. 3 is a diagram of oil separation at an oil storage container connecting portion. FIG. 4 is an explanatory diagram of the principle of oil discharge from the oil storage container.

  The refrigeration cycle apparatus of the present embodiment is applied to an air conditioner that performs indoor cooling or heating. Basically, as shown in FIG. 1, the compressor 5, the four-way valve 6, the outdoor heat exchanger 7, the liquid The pipe 4, the electric expansion valve 8, the indoor heat exchanger 9, and the gas pipe 3 are sequentially connected by a refrigerant pipe and coupled to a closed circuit, and lubricating oil circulates along with the refrigerant in the closed circuit. A refrigerant circuit is configured. That is, the outdoor unit 1 and the indoor unit 2 are connected by a gas pipe 3 and a liquid pipe 4 to form a closed circuit, R410A is sealed as a refrigerant, and ether-based ether compatible with the refrigerant (R410A) as a lubricating oil. Oil is enclosed. Moreover, the oil storage container 10 which can store lubricating oil is provided.

  More specifically, the outdoor unit 1 includes a hermetic compressor 5 capable of adjusting the number of revolutions, a four-way valve 6 that switches the flow path between cooling and heating (in the cooling operation in FIG. 1), An outdoor heat exchanger 7, an oil storage container 10, opening / closing means, that is, an electromagnetic valve 11, and a pressure introducing pipe 12 are provided.

  The indoor unit 2 includes an electric expansion valve 8 and an indoor heat exchanger 9. Although not shown, each of the outdoor heat exchanger 7 and the indoor heat exchanger 9 is provided with a blower, which promotes and adjusts heat exchange with the indoor and outdoor air, respectively.

  Here, a scroll compressor is used as the compressor 5. As shown in FIG. 2, the scroll compressor includes a compression mechanism 54 and a stator 57 and a rotor 58 serving as a drive mechanism in the same hermetic shell 51. The compression mechanism 54 includes a fixed scroll 54c and a swing scroll 54d having plate-like spiral teeth 54a and 54b formed by an involute curve, and a compression chamber is formed between the plate-like spiral teeth 54a and 54b. So that they are engaged with each other. Further, the swing scroll 54d is attached to the main shaft 56 of the drive mechanism in an eccentric state and is relatively rotatable in the hermetic shell 51. Further, both the fixed scroll 54c and the swing scroll 54d are provided. Rotation is prevented by an Oldham ring (not shown) having claws that make a slipping pair, but swinging in the radial direction of the main shaft (a circular motion accompanying eccentricity, hereinafter referred to as "eccentric turning motion") Is configured to be allowed. Then, as the swinging scroll 54d moves eccentrically, refrigerant gas is sucked from the suction pipe 52 between the fixed scroll 54c and the swinging scroll 54d, and the volume decreases toward the center. The gas is pushed out from the discharge pipe 53 in a high pressure state. That is, three operations of refrigerant suction → compression → discharge are periodically and continuously performed in one eccentric turning motion (360 ° eccentric turning motion).

  The oil storage container 10 is capable of storing lubricating oil, and has connection ports 10a and 10b at the top and bottom in the vertical direction as shown in FIGS. 1 and 3, respectively. The bottom connection port 10 b is connected to the high-pressure pipe of the compressor 5 via the electromagnetic valve 11. In the switching position of the four-way valve 6 in FIG. 1, the indoor heat exchanger 9 is an evaporator and the outdoor heat exchanger 7 is a condenser.

  In the refrigeration cycle apparatus of this embodiment, the high-temperature and high-pressure gas refrigerant discharged from the compressor 5 during the cooling operation flows into the outdoor heat exchanger 7 via the four-way valve 6 as shown in FIG. And condense. The high-pressure liquid refrigerant flows into the indoor unit 2 through the liquid pipe 4 and is decompressed to a low pressure by the electric expansion valve 8. And it evaporates, cooling a room | chamber interior with the indoor heat exchanger 9, turns into a low pressure gas refrigerant, and is again attracted | sucked by the compressor 5 via the gas pipe 3 and the four-way valve 6. FIG. At this time, the electromagnetic valve 11 is closed.

  Next, the flow of the lubricating oil inside the compressor 5 will be described with reference to FIG. Lubrication to the bearing portion is performed by differential pressure lubrication using a differential pressure between the suction pressure and the discharge pressure generated in the compression portion. That is, the lubricating oil 59 in the oil reservoir below the sealed shell 51 is communicated with the hollow space 60 provided in the main shaft 56 by the differential pressure, that is, the hollow space 60 of the main shaft 56 communicates with the suction side of the compression portion. , The liquid level upper space of the lubricating oil 59 in the oil reservoir is sucked up by the action of the differential pressure generated by communicating with the discharge side of the compression unit, and through the oil supply communication port communicating from the hollow space 60 to the outer periphery of the main shaft 56, Lubricate the bearing (not shown). At this time, a part of the lubricating oil 59 flows out from the discharge pipe 53 to the refrigeration cycle side together with the high-pressure gas refrigerant.

  In this situation, if a large amount of lubricating oil is enclosed in the refrigeration cycle apparatus, the oil level of the lubricating oil 59 becomes higher than the lower end of the rotor 58, and the rotational resistance is increased by the rotor 58 stirring the lubricating oil. The motor input increases and the driving efficiency is deteriorated. For this reason, it is necessary to isolate the lubricating oil out of the hermetic shell. In this embodiment, the lubricating oil isolation function is given to the oil storage container 10 provided in the outdoor unit 2.

  As shown in FIG. 3, in the oil storage container 10, the suction refrigerant is directed from the top in the vertical direction toward the oil storage container 10, and immediately before that, the gas refrigerant is sucked into the branch pipe connected to the suction side of the compressor 5 to change the traveling direction. As a result, the gas refrigerant flow 101 (shown by a solid line in FIG. 3) is drawn into the compressor 5. However, the lubricating oil stream 102 (shown by a wavy line in FIG. 3) that is heavier than the gas refrigerant and has a high viscosity flows in the form of a liquid film along the droplet or the tube wall. 10 (the state shown in the left diagram of FIG. 3).

  However, this lubricating oil storage mode is transitional, and normally, the oil storage container 10 is full of lubricating oil. In this state, both the gas refrigerant flow 101 and the lubricating oil flow 102 flow toward the suction side of the compressor 5 (the state shown in the right diagram of FIG. 3). Further, in these modes, that is, in a situation where it is desired to isolate the lubricating oil outside the compressor, that is, the sealed shell, the solenoid valve 11 is always closed, and the oil storage container 10 is a cecal tube which is only the inlet.

  According to such an arrangement of the oil storage container 10, it is not necessary to arrange an oil separator on the high pressure side, and the operating efficiency of the present refrigeration cycle apparatus is not reduced due to a pressure loss that occurs during oil separation. Further, in the conventional oil separator arranged on the high pressure side, the refrigerant is slightly bypassed when returning the separated oil to the suction side, but according to this embodiment, loss due to this refrigerant bypass can also be avoided. .

  Next, the operation when lubricating oil is supplied from the oil storage container 10 will be described based on FIG. 4 with reference to FIG. If the lubricating oil 59 at the bottom of the hermetic shell 51 is insufficient, the lubricating oil cannot be sent to the compression mechanism 54, causing problems such as abnormal wear and seizure. In such an operation mode in which the lubricating oil in the sealed shell is reduced, it is necessary to return the excess oil in the oil storage container 10 to the compressor 5.

  In particular, in the heating mode with low outside air, since it starts from the state where the liquid refrigerant has accumulated in the outdoor heat exchanger 7 serving as an evaporator, a large amount of liquid refrigerant flows into the compressor 5 at the start of operation, While the lubricating oil 59 in the sealed shell is diluted, the liquid level of the lubricating oil 59 in the sealed shell temporarily rises, so that a large amount of liquid refrigerant is mixed with the discharge gas, and the lubricating oil 59 is also sealed together. The oil is discharged to the outside, and the lubricating oil hardly exists in the sealed shell.

  In such a case, the electromagnetic valve 11 is opened in this embodiment. As a result, as shown in FIG. 4, the high-pressure discharge gas refrigerant 103 flows from the connection port 10 b at the bottom of the oil storage container 10, and the lubricating oil that has been stored so far overflows the oil storage container 10 and is sucked into the compressor 5. Released to the tube side. The lubricating oil released to the suction pipe quickly forms a flow 102 toward the compressor 5 and raises the oil level in the hermetic shell of the compressor 5.

  In the present embodiment, it is a premise that the lubricating oil is filled in such a large amount that the oil level comes into contact with the lower end of the rotor 58 of the compressor 5 and is necessary even when the oil storage container 10 is full. Since the minimum amount of oil needs to be secured in the sealed shell, the capacity of the oil storage container 10 is necessarily smaller than the difference between the required minimum amount of oil and the amount of oil whose oil level contacts the lower end of the rotor. It will be.

  In this embodiment, the lubricating oil is ether oil that is compatible with the refrigerant R410A. In this case, the so-called liquid back in which the refrigerant is in a two-phase state on the compressor suction side of the refrigeration cycle apparatus. It is conceivable that the lubricating oil that circulates on the low-pressure side becomes diluted when in operation, and the oil separation / storage function cannot be exhibited sufficiently. Therefore, it is desirable to use a weakly compatible lubricating oil such as an alkylbenzene oil, which makes it easier to obtain the effect of improving the efficiency of oil separation.

  As described above, according to the present embodiment, during the cooling or heating operation, the surplus lubricating oil 59 that stays in the sealed shell and deteriorates the operation efficiency is connected to the top connection port 10a to the low-pressure side intake pipe. Since the oil is stored in the oil storage container 10, high-efficiency operation can be performed without generating a factor of efficiency reduction such as pressure loss required for oil separation and refrigerant bypass that occurs along with oil return.

  Further, in a mode where the lubricating oil in the hermetic shell is insufficient, such as when heating is started, the high-pressure discharge gas refrigerant 103 is introduced from the connection port 10b at the bottom of the oil storage container 10, and the lubricating oil that has been stored up to that time is introduced. By discharging to the suction pipe, the amount of oil in the sealed shell can be quickly recovered.

  Here, the scroll compressor has been described as an example of the compressor. However, the present invention is not limited to this, and a rotary compressor or a piston compressor may be employed.

It is a refrigerant circuit figure showing the refrigerating cycle device concerning one embodiment of the present invention. It is a longitudinal section showing the internal structure of the closed type compressor of the refrigerating cycle device concerning one embodiment of the present invention. It is explanatory drawing of the principle of the oil separation in the oil storage container connection part of the refrigerating-cycle apparatus which concerns on one Embodiment of this invention. It is explanatory drawing of the principle of the oil discharge | release from the oil storage container of the refrigeration cycle apparatus which concerns on one Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 5 Compressor, 7 Outdoor heat exchanger, 8 Electric expansion valve (pressure reduction means), 9 Indoor heat exchanger, 10 Oil storage container, 10a Top connection port, 10b Bottom connection port, 11 Solenoid valve (opening / closing means), 51 Sealed shell (shell), 54 compression mechanism, 57 stator (drive mechanism), 58 rotor (drive mechanism).

Claims (3)

A closed circuit having a compression mechanism and a drive mechanism in the same shell, a condenser, a pressure reducing means, and an evaporator are connected in order by a refrigerant pipe to form a closed circuit. A refrigeration cycle device in which lubricating oil circulates with refrigerant,
An oil storage container capable of storing the lubricating oil;
The oil storage container has a connection port at the top and bottom in the vertical direction,
The top connection port is connected to a low pressure line between the evaporator and the compressor;
The refrigeration cycle apparatus, wherein the bottom connection port is connected to a high-pressure pipe of the compressor through an opening / closing means.   The low-pressure pipe connected to the connection port at the top of the oil storage container is installed so that the flow direction to the oil storage container is vertically downward, and immediately before the connection portion with the oil storage container. 2. The refrigeration cycle apparatus according to claim 1, wherein the refrigeration cycle apparatus is branched to the suction side of the compressor.   The refrigeration cycle apparatus according to claim 1 or 2, wherein the refrigerant circulating in the closed circuit and the lubricating oil are in a weakly compatible relationship.

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