JP2009257684A - Compression refrigerating machine and method for recovering lubricating oil for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compression refrigerating machine and a method for recovering lubricating oil for the same, performing stable operation by appropriately recovering the lubricating oil mixed into a refrigerant circulation system. <P>SOLUTION: An evaporator 10, a compressor 13, and a condenser 15 are connected to one another through refrigerant pipes 20, and also a lubricating oil circulation system is provided for supplying the lubricating oil in a lubricating oil tank 33 to the bearing 25 of the compressor 13. The compression refrigerating machine includes: a refrigerant regeneration tank 45 provided with a heater 47 heating a refrigerant with the lubricating oil dissolved to separate the lubricating oil from refrigerant vapor; a pipe 55 connecting the refrigerant regeneration tank 45 to the evaporator 10 to transfer a refrigerant liquid with the lubricating oil in the evaporator 10 dissolved into the refrigerant regeneration tank 45; a pipe 61 connecting the refrigerant regeneration tank 45 to the evaporator 10 to transfer the refrigerant vapor separated from the lubricating oil in the refrigerant regeneration tank 45 into the evaporator 10; and a pipe 65 connecting the refrigerant regeneration tank 45 to the lubricating oil tank 33 to transfer the lubricating oil separated from the refrigerant vapor in the refrigerant regeneration tank 45 into the lubricating oil tank 33. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a compression refrigeration machine suitable for use in a refrigeration air conditioner or the like, and more particularly to a compression refrigeration machine capable of appropriately recovering lubricating oil from a refrigerant and achieving stable operation, and a method for recovering the lubricating oil. is there.

  Conventionally, a compression refrigerator (vapor compression refrigerator) is configured by connecting an evaporator, a compressor driven by a motor (electric motor), a condenser, and an expansion mechanism (expansion valve) with a refrigerant pipe. Has been. In addition, in order to lubricate and cool the compressor (and motor) drive shafts and their bearings, the compression refrigerator stores the drive shaft bearings from the lubricant tank with a lubricant pump. It is pumped into the bearing chamber (see, for example, FIG. 1 of Patent Document 1).

  In general, in a compressor of a compression refrigerator, cooling is performed between the bearing chamber to which the lubricating oil is supplied and the refrigerant circulation system (between the compressor impeller and the bearing chamber, or by using a part of the refrigerant. Between the motor chamber and the bearing chamber of the motor to be separated by a labyrinth. However, the labyrinth seal cannot be said to be perfect, so depending on the operating conditions of the compression refrigerator, a part of the lubricating oil supplied to the bearing chamber may be part of the refrigerant circulation system due to the pressure relationship between the bearing chamber and the refrigerant circulation system. In some cases, it was mixed. Lubricating oil compatible with the refrigerant is mixed in the refrigerant, and then stays in the evaporator, thereby degrading the heat transfer characteristics of the evaporator. As a result, the refrigerating capacity or efficiency of the compression refrigerator is reduced.

  As a method of avoiding this phenomenon, a part of the discharge gas of the compressor is bypassed, and an ejector using this as a drive source carries over from the evaporator and, for example, lubricates on the suction side of the compressor impeller. There was a method of sucking oil and returning the sucked lubricating oil to the lubricating oil tank.

However, when the lubricating oil is recovered using the ejector, the suction capability of the ejector, that is, the recovery capability of the lubricating oil, depends on the discharge pressure of the compressor that is the driving source. For this reason, in the low head operation of a compressor with a low cooling water temperature, the suction capacity of the ejector will not be able to exert its full performance, and it will be difficult to suck and separate the lubricating oil, and a sufficient amount of lubricating oil will be recovered The amount of lubricating oil mixed into the refrigerant circulation system may increase, and troubles such as deterioration in heat transfer performance, surging, and suction low pressure may occur. The most serious problem is that the oil level of the lubricating oil tank decreases due to a decrease in the amount of recovered lubricating oil, the supply hydraulic pressure to the bearing decreases, and the operation of the compression refrigerator cannot be continued. .
JP 2008-14533 A

  The present invention has been made in view of the above points, and an object of the present invention is to properly recover the lubricating oil mixed in the refrigerant circulation system, and as a result, a compression type refrigerator that can continuously perform a stable operation, and its It is to provide a method for recovering a lubricating oil.

  According to the first aspect of the present invention, an evaporator, a compressor, and a condenser are connected by a refrigerant pipe that circulates a refrigerant, a lubricating oil tank in which lubricating oil is stored is installed, and the inside of the lubricating oil tank In a compression type refrigeration machine provided with a lubricating oil circulation system for supplying the lubricating oil to the compressor bearing and returning the lubricating oil lubricated to the bearing to the lubricating oil tank, the refrigerant in which the lubricating oil is dissolved is heated and lubricated. A refrigerant regeneration tank provided with a heating means for separating oil and refrigerant vapor, and a pipe that communicates between the refrigerant regeneration tank and the evaporator to transfer a refrigerant liquid in which the lubricating oil in the evaporator is dissolved to the refrigerant regeneration tank. A communication pipe between the refrigerant regeneration tank and the evaporator to transfer the refrigerant vapor separated from the lubricating oil in the refrigerant regeneration tank to the evaporator; and a communication between the refrigerant regeneration tank and the lubricating oil tank. Refrigerant regeneration unit Click inside in compression refrigerating machine, characterized by comprising a pipe for transferring the lubricating oil tank separated lubricating oil from the refrigerant vapor.

  The invention according to claim 2 of the present application is the compression refrigeration machine according to claim 1, wherein a control valve and a refrigerant are provided in the pipe that communicates between the refrigerant regeneration tank and the evaporator and transfers the refrigerant liquid to the refrigerant regeneration tank. A transfer valve is installed, and a control valve is installed in the pipe for communicating refrigerant between the refrigerant regeneration tank and the evaporator and transferring the refrigerant vapor to the evaporator, and communicates between the refrigerant regeneration tank and the lubricating oil tank. 2. The compression type refrigerator according to claim 1, wherein a control valve and a lubricating oil transfer pump are installed in the pipe for transferring the lubricating oil to the pipe.

  According to the third aspect of the present invention, the evaporator, the compressor, and the condenser are connected by a refrigerant pipe that circulates the refrigerant, and a lubricating oil tank in which lubricating oil is stored is installed. In a compression type refrigeration machine provided with a lubricating oil circulation system for supplying the lubricating oil to the compressor bearing and returning the lubricating oil lubricated to the bearing to the lubricating oil tank, the refrigerant in which the lubricating oil is dissolved is heated and lubricated. A refrigerant regeneration tank provided with a heating means for separating oil and refrigerant vapor, and a pipe that communicates between the refrigerant regeneration tank and the evaporator to transfer a refrigerant liquid in which the lubricating oil in the evaporator is dissolved to the refrigerant regeneration tank. A communication pipe between the refrigerant regeneration tank and the condenser and transferring refrigerant vapor separated from the lubricating oil in the refrigerant regeneration tank to the condenser; and a communication between the refrigerant regeneration tank and the lubricating oil tank. Refrigerant regeneration unit Click inside in compression refrigerating machine, characterized by comprising a pipe for transferring the lubricating oil tank separated lubricating oil from the refrigerant vapor.

  According to a fourth aspect of the present invention, there is provided a compression type refrigerator according to the third aspect, wherein a control valve and a refrigerant are provided in the pipe that communicates between the refrigerant regeneration tank and the evaporator and transfers the refrigerant liquid to the refrigerant regeneration tank. A transfer pump is installed, and a control valve and a compressor are installed in the pipe for transferring the refrigerant vapor to the condenser through communication between the refrigerant regeneration tank and the condenser, and between the refrigerant regeneration tank and the lubricating oil tank. The compression refrigerator according to claim 3, wherein a control valve and a lubricating oil transfer pump are installed in the pipe for transferring the lubricating oil to the lubricating oil tank.

  The invention according to claim 5 of the present application is the compression refrigerator according to claim 1, 2 or 3 or 4, wherein an ejector having a high-pressure side refrigerant vapor compressed by the compressor as a driving source, and the compressor The compressor is provided with a piping for transferring lubricating oil collected in a nearby lubricating oil recovery section to a lubricating oil tank by this ejector.

  According to the sixth aspect of the present invention, the evaporator, the compressor, and the condenser are connected by a refrigerant pipe that circulates the refrigerant, and a lubricating oil tank in which lubricating oil is stored is installed. In the method for recovering lubricating oil of a compression refrigeration machine, the lubricating oil tank is provided with a lubricating oil circulation system that supplies the lubricating oil of the compressor to the bearing of the compressor and returns the lubricating oil lubricated to the bearing to the lubricating oil tank. A step of transferring a predetermined amount of the refrigerant liquid in which the lubricating oil in the evaporator is dissolved into a refrigerant regeneration tank installed separately, and the lubricating liquid and the refrigerant are heated by heating the refrigerant liquid in which the lubricating oil is dissolved in the refrigerant regeneration tank. Separating the vapor from the refrigerant, separating the refrigerant vapor separated from the lubricating oil in the refrigerant regeneration tank to the evaporator or transferring it to the condenser, and separating the refrigerant vapor from the refrigerant vapor in the refrigerant regeneration tank. In lubricating oil recovery method of a compression type refrigerator characterized by comprising the step of transferring the lubricating oil in the lubricating oil tank, a.

  According to the first aspect of the present invention, the lubricant mixed with the lubricating oil is directly transferred from the evaporator to the refrigerant regeneration tank, and the lubricating oil and the refrigerant vapor are separated by heating up in the refrigerant regeneration tank. The lubricating oil mixed in the refrigerant circulation system can be recovered regardless of the operating conditions of the compression refrigerator, and as a result, the stable operation of the compression refrigerator can be continued.

  According to the second aspect of the present invention, the transfer of the refrigerant liquid from the evaporator to the refrigerant regeneration tank, the transfer of the refrigerant vapor from the refrigerant regeneration tank to the evaporator, and the lubricating oil from the refrigerant regeneration tank to the lubricating oil tank. Can be smoothly performed with a simple configuration.

  According to the third aspect of the present invention, the lubricant mixed with the lubricating oil is directly transferred from the evaporator to the refrigerant regeneration tank, and the lubricating oil and the refrigerant vapor are separated by heating in the refrigerant regeneration tank. The lubricating oil mixed in the refrigerant circulation system can be recovered regardless of the operating conditions of the compression refrigerator, and as a result, the stable operation of the compression refrigerator can be continued. Furthermore, in the case of this invention, since the refrigerant | coolant vapor | steam is introduce | transduced into the high voltage | pressure side (condenser) of the refrigerating cycle, the efficiency fall of a compression type refrigerator can be prevented.

  According to the fourth aspect of the present invention, the transfer of the refrigerant liquid from the evaporator to the refrigerant regeneration tank, the transfer of the refrigerant vapor from the refrigerant regeneration tank to the condenser, and the lubricating oil from the refrigerant regeneration tank to the lubricating oil tank. Can be smoothly performed with a simple configuration.

  According to the fifth aspect of the present invention, it is possible to use a lubricating oil recovery mechanism that uses an ejector and a lubricating oil recovery mechanism that uses a refrigerant regeneration tank, thereby improving the recovery efficiency of the lubricating oil.

  According to the sixth aspect of the present invention, the lubricant mixed with the lubricating oil is directly transferred from the evaporator to the refrigerant regeneration tank, and the lubricating oil and the refrigerant vapor are separated by heating up in the refrigerant regeneration tank. The lubricating oil mixed in the refrigerant circulation system can be recovered regardless of the operating conditions of the compression refrigerator, and as a result, the stable operation of the compression refrigerator can be continued. In particular, when the refrigerant vapor separated from the lubricating oil in the refrigerant regeneration tank is transferred to the high-pressure side (condenser), it is possible to prevent the efficiency of the compression refrigerator from decreasing.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[First Embodiment]
FIG. 1 is an overall schematic configuration diagram of a compression refrigerator 1-1 according to the first embodiment of the present invention. A compression refrigerator 1-1 shown in the figure is a compression refrigerator that performs a vapor compression refrigeration cycle, and includes a closed cycle (refrigeration cycle) into which a refrigerant is injected. The evaporator 10 that takes heat from the fluid to be cooled) and evaporates the refrigerant to exert a refrigeration effect, the compressor 13 that compresses the refrigerant (refrigerant vapor) that has evaporated to become steam, and the compressed steam is cooled with cooling water (cooling). A condenser 15 that cools and condenses with a fluid) and an expansion mechanism (expansion valve) 19 that decompresses and expands the condensed refrigerant are connected by a refrigerant pipe 20 that circulates the refrigerant.

  Here, the compressor 13 has its impeller 13 a driven by the drive shaft 23 of the motor 21. The drive shaft 23 of the motor 21 and the compressor 13 (the impeller 13a) is rotatably supported by a bearing 25. The motor 21 and the condenser 15 are connected by pipes 27 and 29. The pipe 27 is connected to the lower part of the condenser 15, the refrigerant for cooling the motor is supplied from the condenser 15 to the motor 21 by the refrigerant pump 31 installed in the pipe 27, and the refrigerant after cooling the motor 21 is sent through the pipe 29. It is returned to the condenser 15.

  The compression refrigerator 1-1 is provided with a lubricating oil tank 33 for storing lubricating oil for lubricating the bearing 25 of the motor 21, and pipes 35 and 37 are connected between the lubricating oil tank 33 and the bearing 25. Then, the lubricating oil in the lubricating oil tank 33 is supplied to the bearing 25 by the lubricating oil pump 39 installed in the pipe 35, and the lubricating oil that lubricated the bearing 25 is returned to the lubricating oil tank 33 through the pipe 37. A circulatory system is configured. The lubricating oil tank 33 and the evaporator 10 are connected by a pressure equalizing pipe 41. Also, a heater 43 is installed in the lubricating oil tank 33 to return the refrigerant vapor, which has been vaporized by heating the lubricating oil in which the refrigerant has melted, to the evaporator 10 via the pressure equalizing pipe 41.

  On the other hand, apart from the lubricating oil tank 33, a refrigerant regeneration tank 45 for separating the refrigerant and the lubricating oil is installed. A heating means (hereinafter referred to as “heater”) 47, a liquid level detector 49, a pressure detector 51, and a temperature detector 53 are attached to the refrigerant regeneration tank 45. Here, the heater 47 heats up the refrigerant in which the lubricating oil stored in the refrigerant regeneration tank 45 is dissolved to separate the lubricating oil and the refrigerant vapor. The liquid level detector 49 detects the liquid level of the refrigerant in which the lubricating oil in the refrigerant regeneration tank 45 is dissolved, and the liquid level detector 49 has different liquid level heights a, b and c. Is detected. The height a is the highest position, and becomes a lower position as the height b and the height c are reached. The pressure detector 51 detects the pressure of the gas phase portion in the refrigerant regeneration tank 45, and the temperature detector 53 detects the temperature of the liquid phase portion in the refrigerant regeneration tank 45.

  Further, the lowermost part, which is the liquid phase part of the evaporator 10, communicates with the refrigerant regeneration tank 45 by a pipe 55, and a refrigerant transfer pump 57 and a control valve 59 including an electromagnetic valve are attached to the pipe 55. Further, the upper part that becomes the gas phase part of the evaporator 10 and the upper part that becomes the gas phase part of the refrigerant regeneration tank 45 communicate with each other by a pipe 61, and a control valve 63 made of an electromagnetic valve is attached in the pipe 61. ing. Further, the lowermost part, which is the liquid phase part of the refrigerant regeneration tank 45, and the lubricating oil tank 33 are communicated by a pipe 65, and a lubricating oil transfer pump 67 and a control valve 69 are attached in the pipe 65. Further, the evaporator 10 is provided with temperature detectors 71 and 73 for measuring the evaporation temperature and the cold water outlet temperature, respectively.

  FIG. 2 is a diagram showing a control means 80 that controls the recovery of the lubricating oil in the compression refrigerator 1-1. As shown in the figure, the control means 80 includes the liquid level detector 49, the pressure detector 51, the temperature detector 53, and the temperature detectors 71 and 73, respectively, and the position of the liquid level and the gas phase portion in the refrigerant regeneration tank 45. , The temperature of the liquid phase part, the detection signal of the evaporation temperature of the evaporator 10 and the cold water outlet temperature, the heater control signal for controlling the heating / stopping of the heater 47, the refrigerant transfer pump 57 and the lubrication An operation control signal for controlling start / stop of the oil transfer pump 67 is output, and an opening / closing control signal for controlling the opening / closing of the control valve 59, the control valve 63, and the control valve 69 is output.

  In the compression refrigerator 1-1, if cold water is flowed to the evaporator 10, cooling water is flowed to the condenser 15, the motor 21 is started and the compressor 13 is driven, the refrigerant circulates in this refrigeration cycle, The compression refrigerator 1-1 is operated. On the other hand, by starting the refrigerant pump 31, a part of the condensed refrigerant liquid in the condenser 15 is supplied to the motor 21, and after cooling the motor 21, the vapor is returned to the condenser 15 to be condensed and liquefied. On the other hand, by starting the lubricating oil pump 39, the lubricating oil in the lubricating oil tank 33 is supplied to the bearing 25, and the bearing 25 is lubricated and cooled. The lubricating oil that lubricated the bearing 25 is again supplied by the pipe 37 to the lubricating oil tank. Return to 33.

  When the compressor type refrigerator 1-1 is operated, as described above, lubricating oil compatible with the refrigerant moves and mixes in the refrigerant circulation system, stays in the evaporator 10 and boils the evaporator 10. Inhibits heat transfer and reduces efficiency. Therefore, in the compression refrigerator 1-1, during operation, the lubricating oil mixed in the refrigerant circulation system is recovered in the lubricating oil tank 33 (lubricating oil circulation system) by the following control procedure, for example. The following lubricating oil recovery operation is performed by a control command signal from the control means 80.

  That is, after the operation of the compression refrigerator 1-1 is started as described above, the control means 80 determines the LTD (cold water outlet temperature and evaporation temperature [of the evaporator 10) from the temperature detection signal fetched from the temperature detectors 71 and 73. When the LTD value exceeds a predetermined value, it is determined that the amount of refrigerant liquid in the evaporator 10 is insufficient, that is, the lubricant retention amount has increased to a predetermined amount or more. The following control is automatically started.

  That is, when the LTD exceeds a predetermined value, the refrigerant transfer pump 57 is first operated, and then the control valve 59 is opened. As a result, the refrigerant (the refrigerant liquid in which the lubricating oil is dissolved) is transferred from the evaporator 10 to the refrigerant regeneration tank 45. Next, when the liquid level detector 49 detects that the liquid level of the refrigerant regeneration tank 45 has reached the position of the height a, the control valve 59 is closed and the refrigerant transfer pump 57 is stopped.

  Next, the heater 47 is turned on and heated, the refrigerant liquid in which the lubricating oil is dissolved is heated up, and the refrigerant liquid is separated from the lubricating oil as refrigerant vapor. As a result, the pressure of the gas phase (refrigerant vapor) in the refrigerant regeneration tank 45 rises. Therefore, when the pressure of the refrigerant regeneration tank 45 detected by the pressure detector 51 becomes equal to or higher than a preset value, the control valve 63. The refrigerant vapor in the refrigerant regeneration tank 45 is transferred to the evaporator 10 due to the pressure difference between the refrigerant regeneration tank 45 and the evaporator 10. When the refrigerant level separated from the lubricating oil is transferred to the evaporator 10 and the liquid level in the refrigerant regeneration tank 45 is lowered to the height b, the control valve 63 is closed. At this time, the liquid in the refrigerant regeneration tank 45 is mainly lubricating oil.

  On the other hand, when the heater 47 continues to heat up and the temperature detector 53 detects that the temperature of the liquid in the refrigerant regeneration tank 45, which has become mainly lubricating oil, has reached a predetermined temperature or higher, the lubricating oil transfer pump 67 is turned on. The control valve 69 is opened, and the lubricating oil in the refrigerant regeneration tank 45 is transferred to the lubricating oil tank 33. When the liquid level in the refrigerant regeneration tank 45 is lowered to the height c, the control valve 69 is closed and the lubricating oil transfer pump 67 is stopped. Through the above operation, one recovery operation for separating the lubricating oil from the refrigerant and recovering the lubricating oil into the refrigerant circulation system and the lubricating oil circulation system is completed.

  If the LTD of the evaporator 10 falls below the set value in the collecting operation, the collecting operation is interrupted until it exceeds the set value again. On the other hand, if the LTD still does not fall below the set value due to the collecting operation, the collecting operation is continuously performed until the LTD falls below the set value.

  As described above, the compression refrigerator 1-1 is connected to the refrigerant regeneration tank 45 and the evaporator 10, and the piping for transferring the refrigerant liquid in which the lubricating oil in the evaporator 10 is dissolved to the refrigerant regeneration tank 45. 55, a pipe 61 that communicates between the refrigerant regeneration tank 45 and the evaporator 10 and transfers the refrigerant vapor separated from the lubricating oil in the refrigerant regeneration tank 45 to the evaporator 10, and between the refrigerant regeneration tank 45 and the lubricating oil tank 33. And the piping 65 for transferring the lubricating oil separated from the refrigerant vapor in the refrigerant regeneration tank 45 to the lubricating oil tank 33, so that the refrigerant liquid mixed with the lubricating oil from the evaporator 10 is provided. Is directly transferred to the refrigerant regeneration tank 45 and heated in the refrigerant regeneration tank 45, whereby the lubricating oil component and the refrigerant vapor can be separated. Therefore, the lubricating oil mixed in the refrigerant circulation system is removed from the compression refrigerator 1-1. Be recovered irrespective of the operating conditions, it can continue stable operation of the resulting compression refrigerating machine 1-1. In particular, in the case of the compression refrigerator 1-1, a heater 47 or the like is installed in the refrigerant regeneration tank 45, or a refrigerant transfer pump 57, a lubricant transfer pump 67, or control valves 59, 63, 69 are installed in the pipes 55, 61, 65. The refrigerant liquid is transferred from the evaporator 10 to the refrigerant regeneration tank 45, the refrigerant vapor is transferred from the refrigerant regeneration tank 45 to the evaporator 10, and the lubricant oil tank is transferred from the refrigerant regeneration tank 45 to the lubricating oil tank. The lubricating oil can be smoothly transferred to 33, which is preferable.

[Second Embodiment]
FIG. 3 is an overall schematic configuration diagram of a compression refrigerator 1-2 according to the second embodiment of the present invention. Similarly to the compression refrigerator 1-1, the compression refrigerator 1-2 shown in the figure is a compression refrigerator that performs a vapor compression refrigeration cycle. In the compression type refrigerator 1-2 shown in the figure, the same or corresponding parts as those in the compression type refrigerator 1-1 shown in FIGS. Items other than those described below are the same as those of the compression refrigerator 1-1 shown in FIGS.

  That is, the compression refrigerator 1-2 is also composed of a closed cycle (refrigeration cycle) into which refrigerant is injected, and this refrigeration cycle takes heat from cold water (cooled fluid) and evaporates the refrigerant to exert a refrigeration effect. , The compressor 13 that compresses the refrigerant (refrigerant vapor) that has been evaporated into vapor, the condenser 15 that cools and compresses the compressed vapor with cooling water (cooling fluid), and depressurizes the condensed refrigerant An expansion mechanism (expansion valve) 19 for expansion is connected by a refrigerant pipe 20 that circulates the refrigerant.

  The difference between the compression type refrigerator 1-1 and the compression type refrigerator 1-1 is that, in the compression type refrigerator 1-1, the upper part which is the gas phase part of the evaporator 10 and the refrigerant regeneration tank 45. The upper part, which is the gas phase part, is communicated by the pipe 61, and the control valve 63 is attached in the pipe 61, but this is omitted. Instead, the upper part of the condenser 15 and the refrigerant regeneration tank 45 The upper part which becomes the gas phase part is communicated by a pipe 75, and a control valve 77 made of an electromagnetic valve and a compressor 79 are attached in the pipe 75. Although not shown, the control means 80 used for the compression type refrigerator 1-2 does not output an opening / closing control signal for controlling the opening / closing of the control valve 63 shown in FIG. And an operation control signal for controlling the start / stop of the compressor 79 is output.

  Then, the operation of the compression refrigerator 1-2 is started, the refrigerant pump 31 is started to cool the motor 21, and the lubricating oil pump 39 is started to start lubrication and cooling of the bearing 25.

  The procedure for collecting the lubricating oil into the lubricating oil tank 33 is performed as follows, for example. That is, first, the control means 80 obtains the LTD of the evaporator 10 from the temperature detection signals fetched from the temperature detectors 71 and 73, and when the LTD value exceeds a predetermined value, the amount of accumulated lubricating oil in the evaporator 10 exceeds a predetermined amount. When it is determined that the refrigerant has increased, first, the refrigerant transfer pump 57 is operated, and then the control valve 59 is opened to transfer the refrigerant (the refrigerant liquid in which the lubricating oil is dissolved) from the evaporator 10 to the refrigerant regeneration tank 45. Next, when the liquid level detector 49 detects that the liquid level of the refrigerant regeneration tank 45 has reached the position of the height a, the control valve 59 is closed and the refrigerant transfer pump 57 is stopped. Next, the heater 47 is turned on to heat up the refrigerant liquid in which the lubricating oil is dissolved, and the refrigerant liquid is separated from the lubricating oil as refrigerant vapor. As a result, the pressure of the gas phase (refrigerant vapor) in the refrigerant regeneration tank 45 rises. Therefore, when the pressure in the refrigerant regeneration tank 45 detected by the pressure detector 51 becomes equal to or higher than a predetermined set value, the compressor 79. Then, the control valve 77 is opened, the refrigerant vapor in the refrigerant regeneration tank 45 is forcibly extracted by the compressor 79, and transferred to the condenser 15 on the high pressure side of the compression type refrigerator 1-2. To do. When the refrigerant level separated from the lubricating oil is transferred to the condenser 15 and the liquid level in the refrigerant regeneration tank 45 is lowered to the height b, the control valve 77 is closed and the compressor 79 is stopped. At this time, the liquid in the refrigerant regeneration tank 45 is mainly lubricating oil.

  On the other hand, when the heater 47 continues to heat up and the temperature detector 53 detects that the temperature of the liquid in the refrigerant regeneration tank 45, which has become mainly lubricating oil, has reached a predetermined temperature or higher, the lubricating oil transfer pump 67 is turned on. The control valve 69 is opened, and the lubricating oil in the refrigerant regeneration tank 45 is transferred to the lubricating oil tank 33. When the liquid level in the refrigerant regeneration tank 45 is lowered to the height c, the control valve 69 is closed and the lubricating oil transfer pump 67 is stopped. With the above operation, one recovery operation is completed in which the lubricating oil is separated from the refrigerant and recovered into the refrigerant circulation system and the lubricating oil circulation system. Whether the collection operation is interrupted or continued thereafter is the same as in the case of the compression refrigerator 1-1.

  As described above, the compression refrigerator 1-2 is connected to the refrigerant regeneration tank 45 and the evaporator 10 to transfer the refrigerant liquid in which the lubricating oil in the evaporator 10 is dissolved to the refrigerant regeneration tank 45. 55, a pipe 75 that communicates between the refrigerant regeneration tank 45 and the condenser 15 and transfers refrigerant vapor separated from the lubricating oil in the refrigerant regeneration tank 45 to the condenser 15, and between the refrigerant regeneration tank 45 and the lubricating oil tank 33. And the piping 65 for transferring the lubricating oil separated from the refrigerant vapor in the refrigerant regeneration tank 45 to the lubricating oil tank 33, so that the refrigerant liquid mixed with the lubricating oil from the evaporator 10 is formed. Is directly transferred to the refrigerant regeneration tank 45 and heated in the refrigerant regeneration tank 45, whereby the lubricating oil component and the refrigerant vapor can be separated. Therefore, the lubricating oil mixed in the refrigerant circulation system is removed from the compression refrigerator 1-. Of recovered regardless of the operating conditions, it can continue stable operation of the resulting compression refrigerating machine 1-2. Similarly to the case of the compression refrigerator 1-1, the refrigerant liquid is transferred from the evaporator 10 to the refrigerant regeneration tank 45 and the refrigerant vapor is transferred from the refrigerant regeneration tank 45 to the condenser 15 with a simple configuration. Therefore, it is possible to smoothly transfer the lubricating oil from the refrigerant regeneration tank 45 to the lubricating oil tank 33, which is preferable.

  Further, in the compression type refrigerator 1-1, the refrigerant vapor separated in the refrigerant regeneration tank 45 is introduced into the evaporator 10 (low pressure side). This refrigerant vapor becomes a heat loss of the evaporator 10, and the compression type refrigeration is performed. Reduce the efficiency of the machine 1-1. On the other hand, in the compression type refrigerator 1-2, the vapor phase portion of the refrigerant regeneration tank 45 and the condenser 15 are communicated, and the refrigerant vapor in the refrigerant regeneration tank 45 is forcibly extracted by the compressor 79, and is compressed. Since the refrigerant vapor is introduced into the high-pressure side (condenser 15) of the refrigeration cycle of the refrigerator 1-2, it is possible to improve the efficiency of the compression refrigerator 1-2.

[Third Embodiment]
FIG. 4 is an overall schematic configuration diagram of a compression refrigerator 1-3 according to the third embodiment of the present invention. Similarly to the compression refrigerator 1-1, the compression refrigerator 1-3 shown in the figure is also a compression refrigerator that performs a vapor compression refrigeration cycle. In the compression type refrigerator 1-3 shown in the same figure, the same or corresponding parts as those of the compression type refrigerator 1-1 shown in FIGS. Items other than those described below are the same as those of the compression refrigerator 1-1 shown in FIGS.

  That is, the compression refrigerator 1-3 is also composed of a closed cycle (refrigeration cycle) in which refrigerant is injected, and this refrigeration cycle takes heat from cold water (cooled fluid) and evaporates the refrigerant to exert a refrigeration effect. , The compressor 13 that compresses the refrigerant (refrigerant vapor) that has been evaporated into vapor, the condenser 15 that cools and compresses the compressed vapor with cooling water (cooling fluid), and depressurizes the condensed refrigerant An expansion mechanism (expansion valve) 19 for expansion is connected by a refrigerant pipe 20 that circulates the refrigerant.

  The difference between the compression refrigerator 1-1 and the compression refrigerator 1-1 in this compression refrigerator 1-3 is that, in addition to the lubricating oil recovery mechanism by the refrigerant regeneration tank 45 used in the compression refrigerator 1-1, an ejector is further provided. The lubricating oil recovery mechanism to be used is installed. That is, in the compression refrigerator 1-3, an ejector 90 is installed in addition to the configuration of the compression refrigerator 1-1, and a refrigerant on the discharge side of the ejector 90 and the compressor 13 serves as a drive source for the ejector 90. A pipe 91 for driving the ejector is connected between the pipe 20, a pipe 93 communicating with the lubricating oil tank 33 is connected to the discharge side of the ejector 90, and the suction side of the ejector 90 and the suction side of the compressor 13 are connected. A piping 95 is connected between the lubricating oil recovery units 100 to constitute a lubricating oil recovery mechanism. Control valves 97 and 99 made of electromagnetic valves are attached to the pipe 93 and the pipe 95, respectively. The lubricating oil recovery unit 100 is provided in a portion where the lubricating oil on the suction side of the impeller 13a stays. That is, it is known that a part of the lubricating oil collected in the evaporator 10 is carried over together with the refrigerant vapor evaporated in the evaporator 10 and stays in the vicinity of the compressor 13. A pipe 95 is connected to this. Although not shown, the control means 80 used in the compression refrigerator 1-3 outputs an opening / closing control signal for controlling opening / closing of the control valves 97 and 99 in addition to the configuration shown in FIG.

  Then, the operation of the compression refrigerator 1-3 is started, the refrigerant pump 31 is started to cool the motor 21, and the lubricating oil pump 39 is started to start lubrication and cooling of the bearing 25.

  On the other hand, the operation of recovering the lubricating oil to the lubricating oil tank 33 is performed by using both the lubricating oil recovery mechanism by the refrigerant regeneration tank 45 and the lubricating oil recovery mechanism by the ejector 90. That is, for example, when the compressor 13 is operating at a high head (whether or not the head is a high head is obtained by measuring, for example, the pressure difference between the suction and discharge of the compressor 13), the suction performance of the ejector 90 is high. The valves 97 and 99 are opened, and thereby the lubricant accumulated in the lubricant recovery unit 100 is sucked by the ejector 90 using the compressor discharge side (high pressure side) refrigerant vapor compressed by the compressor 13 as a drive source. It is transferred to the lubricating oil tank 33 and the lubricating oil is recovered.

  On the other hand, when the compressor 13 is operating at a low head, the control valves 97 and 99 are closed to stop the recovery operation of the lubricating oil by the ejector 90. Further, if the LTD value exceeds a predetermined value, the refrigerant transfer pump 57 is operated. Then, the control valve 59 is opened, the refrigerant liquid is transferred from the evaporator 10 to the refrigerant regeneration tank 45, and the lubricating oil is lubricated in the same steps as in the case of the compression refrigerator 1-1. Collect in the tank 33.

  Thus, if the recovery of the lubricating oil by the ejector 90 and the recovery of the lubricating oil by the refrigerant regeneration tank 45 are used in combination, the heater 47 and the refrigerant transfer pump 57 are used when the compressor 13 has a high head. Further, it is not necessary to use the lubricant transfer pump 67 or the like, so that power can be saved, and the recovery efficiency of the lubricant can be improved as a whole.

  As described above, the compression refrigerator 1-3 has the same configuration as that of the compression refrigerator 1-1, and also uses an ejector having a high-pressure side refrigerant vapor compressed by the compressor 13 as a drive source. 90 and pipes 91, 93, and 95 for transferring the lubricating oil collected in the lubricating oil collecting section 100 near the compressor 13 to the lubricating oil tank 33 by the ejector 90. Therefore, a lubricating oil collecting mechanism using the ejector 90 is provided. The lubricating oil recovery mechanism using the refrigerant regeneration tank 45 can be used together, and the recovery efficiency of the lubricating oil can be increased. Both lubricant recovery mechanisms may be operated separately or simultaneously depending on the situation.

  It goes without saying that the lubricating oil recovery mechanism by the ejector 90 used in the compression refrigerator 1-3 can be applied to the compression refrigerator 1-2 as it is.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Is possible. It should be noted that any configuration not directly described in the specification and drawings is within the scope of the technical idea of the present invention as long as the effects and advantages of the present invention are exhibited. For example, in the above-described compression refrigerator 1-3, the lubricating oil recovery unit 100 is provided on the upstream side of the impeller 13a of the compressor 13, but stays in other parts (lubricating oil recovery unit) in the vicinity of the compressor 13. Lubricating oil may be recovered. In each of the above examples, the compression type refrigerator has one refrigeration cycle. However, the present invention may be applied to a compression type refrigerator having a plurality of refrigeration cycles. That is, it has a plurality of refrigeration cycles filled with refrigerant, and each refrigeration cycle takes heat from the fluid to be cooled and evaporates the refrigerant to exert a refrigeration effect, and compresses the evaporated refrigerant into vapor The present invention may be applied to a compression refrigerator having a structure including a compressor, a condenser that cools and condenses compressed vapor with a cooling fluid, and an expansion mechanism that expands the condensed refrigerant liquid. In that case, it is preferable to drive the plurality of compressors with one motor. In addition to the cooling water, other sensible heat changing fluid such as cooling air may be used as the cooling fluid. Further, as the fluid to be cooled, in addition to cold water, other fluids that change sensible heat such as brine may be used.

1 is an overall schematic configuration diagram of a compression refrigerator 1-1. It is a figure which shows the control means. It is a whole schematic block diagram of the compression type refrigerator 1-2. It is a whole schematic block diagram of the compression refrigerator 1-3.

Explanation of symbols

1-1 Compression Refrigerator 10 Evaporator 13 Compressor 15 Condenser 19 Expansion Valve (Expansion Mechanism)
20 Refrigerant piping 21 Motor 23 Drive shaft 25 Bearing 33 Lubricating oil tank 35, 37, 55, 61, 65 Piping 39 Lubricating oil pump 45 Refrigerant regeneration tank 47 Heater (heating means)
49 Liquid level detector 51 Pressure detector 53 Temperature detector 57 Refrigerant transfer pump 59, 63, 69 Control valve 67 Lubricating oil transfer pump 71, 73 Temperature detector 80 Control means 1-2 Compressor refrigerator 75 Piping 77 Control valve 79 Compressor 1-3 Compressive refrigerator 90 Ejectors 91, 93, 95 Piping 97, 99 Control valve 100 Lubricating oil recovery section

Claims (6)

The evaporator, the compressor, and the condenser are connected by a refrigerant pipe that circulates the refrigerant, and a lubricating oil tank in which lubricating oil is stored is installed, and the lubricating oil in the lubricating oil tank is used as a bearing for the compressor. In a compression type refrigeration machine provided with a lubricating oil circulation system that supplies lubricating oil that has been supplied and lubricated to the lubricating oil tank.
A refrigerant regeneration tank provided with a heating means for heating the refrigerant in which the lubricating oil is dissolved to separate it into the lubricating oil and the refrigerant vapor, and the lubricating oil in the evaporator is dissolved in communication between the refrigerant regeneration tank and the evaporator. A pipe for transferring the refrigerant liquid to the refrigerant regeneration tank, a pipe for communicating the refrigerant vapor separated from the lubricating oil in the refrigerant regeneration tank by communicating between the refrigerant regeneration tank and the evaporator, and the refrigerant regeneration A compression type refrigeration machine comprising: a piping that communicates between the tank and the lubricating oil tank and transfers lubricating oil separated from the refrigerant vapor in the refrigerant regeneration tank to the lubricating oil tank. In the compression refrigerator according to claim 1,
A control valve and a refrigerant transfer pump are installed in the pipe that communicates between the refrigerant regeneration tank and the evaporator and transfers the refrigerant liquid to the refrigerant regeneration tank, and communicates between the refrigerant regeneration tank and the evaporator so that the refrigerant vapor is supplied to the evaporator. A control valve is installed in the pipe for transferring the oil, and a control valve and a lubricating oil transfer pump are installed in the pipe for transferring the lubricating oil to the lubricating oil tank by communicating between the refrigerant regeneration tank and the lubricating oil tank. The compression type refrigerator according to claim 1. The evaporator, the compressor, and the condenser are connected by a refrigerant pipe that circulates the refrigerant, and a lubricating oil tank in which lubricating oil is stored is installed, and the lubricating oil in the lubricating oil tank is used as a bearing for the compressor. In a compression type refrigeration machine provided with a lubricating oil circulation system that supplies lubricating oil that has been supplied and lubricated to the lubricating oil tank.
A refrigerant regeneration tank provided with a heating means for heating the refrigerant in which the lubricating oil is dissolved to separate it into the lubricating oil and the refrigerant vapor, and the lubricating oil in the evaporator is dissolved in communication between the refrigerant regeneration tank and the evaporator. A pipe for transferring the refrigerant liquid to the refrigerant regeneration tank, a pipe for communicating the refrigerant vapor separated from the lubricating oil in the refrigerant regeneration tank by communicating between the refrigerant regeneration tank and the condenser, and the refrigerant regeneration A compression type refrigeration machine comprising: a piping that communicates between the tank and the lubricating oil tank and transfers lubricating oil separated from the refrigerant vapor in the refrigerant regeneration tank to the lubricating oil tank. In the compression refrigerator according to claim 3,
A control valve and a refrigerant transfer pump are installed in the piping that communicates between the refrigerant regeneration tank and the evaporator and transfers the refrigerant liquid to the refrigerant regeneration tank, and communicates between the refrigerant regeneration tank and the condenser to connect the refrigerant vapor to the condenser. A control valve and a compressor are installed in the piping for transferring the oil, and a control valve and a lubricating oil transfer pump are installed in the piping for transferring the lubricating oil to the lubricating oil tank through communication between the refrigerant regeneration tank and the lubricating oil tank. The compression type refrigerator according to claim 3, wherein the compression refrigerator is used. In the compression type refrigerator according to claim 1 or 2, 3 or 4,
An ejector using a high-pressure side refrigerant vapor compressed by the compressor as a drive source, and a pipe for transferring the lubricating oil collected in the lubricating oil recovery section near the compressor to the lubricating oil tank are installed. The compression type refrigerator characterized by this. The evaporator, the compressor, and the condenser are connected by a refrigerant pipe that circulates the refrigerant, and a lubricating oil tank in which lubricating oil is stored is installed, and the lubricating oil in the lubricating oil tank is used as a bearing for the compressor. In a method for recovering lubricating oil of a compression refrigeration machine comprising a lubricating oil circulation system that supplies lubricating oil that has been supplied and lubricated to a lubricating oil tank.
Transferring a predetermined amount of refrigerant liquid in which the lubricating oil in the evaporator is dissolved in a refrigerant regeneration tank installed separately from the lubricating oil tank;
Separating the lubricating oil and the refrigerant vapor by heating the refrigerant liquid in which the lubricating oil is dissolved in the refrigerant regeneration tank;
Transferring the refrigerant vapor separated from the lubricating oil in the refrigerant regeneration tank to an evaporator or transferring it to a condenser;
Transferring the lubricating oil separated from the refrigerant vapor in the refrigerant regeneration tank to the lubricating oil tank;
A method for recovering lubricating oil of a compression type refrigerator, comprising:

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