JP5543093B2 - Compressive refrigerator and operation method thereof - Google Patents

Description

  The present invention relates to a compressor-type refrigerator including a compressor, a condenser, and an evaporator, and an operation method thereof.

  Conventionally, this type of compression refrigerator includes a compressor driven by an electric motor, a condenser, and an evaporator, and includes a refrigeration cycle in which these are connected by a refrigerant pipe. In addition, this type of compression refrigerator includes a lubricating oil circulation system for lubricating bearings and transmission gears. This lubricating oil circulation system includes an oil pump and a lubricating oil tank, and the lubricating oil in the lubricating oil tank is supplied to the bearing and transmission gear through the lubricating oil supply pipe, and the lubricating oil after lubrication is returned to the return pipe. It is comprised so that it may return to a lubricating oil tank through.

  In many cases, a compressor of a turbo chiller has a hermetically sealed structure including an electric motor and a bearing (including a speed increasing gear) (sealed turbo chiller). In this structure, the movement of the refrigerant between the lubricating oil circulation system and the refrigerant circulation system is limited between the bearing or the speed increasing gear portion and the refrigerant circulation system by using a labyrinth seal or an oil seal. Yes. However, it is not possible to completely stop the lubricating oil from leaking into the refrigeration cycle (refrigerant circulation system). Over a long period of time, the lubricating oil will decrease (leak), and the lubricating oil will leak into the refrigerant circulation system. It is usually unavoidable to mix. Due to the long-term leakage of the lubricating oil, the oil cannot be circulated due to the lack of oil in the lubricating oil circulation system. In addition, when lubricating oil is mixed or dissolved in the refrigerant circulation system and accumulates, there is a problem that heat transfer on the refrigerant side deteriorates and further, the refrigerant vapor pressure characteristics change.

  As a countermeasure against this, conventionally, the lubricating oil is recovered from the refrigerant circulation system. In the conventional example shown in Patent Document 1, the refrigerant mixed with the lubricating oil collected in the suction section of the compressor is sucked by an ejector using compressor refrigerant vapor as a drive source and collected in an oil tank. When the refrigerant concentration of the recovered liquid is high, the refrigerant concentration in the oil tank increases, and foaming is likely to occur. Therefore, in Patent Document 1, the oil-mixed refrigerant accumulated in the compressor suction portion is heated and concentrated (heated to evaporate and discharge the refrigerant and concentrate the oil), and then collected in an oil tank by an ejector. In patent document 1, it assumes that the refrigerant | coolant mist from an evaporator accumulates in a compressor suction part. However, the compressor / refrigerator has high vapor-liquid separation in the evaporator and mist is not sucked into the compressor, or a compression type in which the mist is generated at full load and the suction part has a low flow rate at partial load and does not generate mist. In the refrigerator, there is a problem that oil cannot be recovered.

  In such a case, the refrigerant liquid in the evaporator is directly recovered. For example, in Patent Document 2, refrigerant liquid in an evaporator is sucked by an ejector using compressed refrigerant vapor as a drive source and collected in an oil tank. These refrigerators that collect oil with an ejector equalize the pressure of the oil tank to the pressure of the low pressure part such as the suction part from the evaporator or the evaporator of the compressor. The ejector can be driven by the pressure difference from the low pressure of the compressor. The steam that drives the ejector is a load on the evaporator. Since the ejector is not efficient as a pump, it becomes a relatively large load. Further, when the cooling water temperature decreases, the condenser pressure decreases and the ejector cannot be driven.

  In a compression refrigeration machine that improves start-up characteristics by equalizing the oil tank to the economizer or condenser pressure, avoiding sudden pressure drop in the oil tank when starting the compression refrigeration machine, and suppressing the occurrence of forming. In an ejector that uses a mixed solution of refrigerant and oil at the low pressure side of the suction part of the evaporator or compressor, and the discharge steam of the compressor (steam at the condenser pressure) as a drive source, an oil tank part having a high pressure However, even if it cannot be recovered (lack of head) and can be returned, the efficiency deteriorates, resulting in a heavy load on the evaporator.

  Further, in order to improve the starting characteristics, in the method of equalizing the oil tank to the high pressure part from the evaporator, for example, an economizer, the oil tank is stopped for a long time at a room temperature of 20 ° C. and an oil tank temperature of 55 ° C. %, The economizer dew point (saturation temperature) after start-up is about 20 ° C, and the dew point of the oil tank settles down to about 20 ° C, so there is almost no change in the concentration of lubricating oil, so there is no worry of forming , Startup time can be greatly reduced. Further, in the method of pressure equalizing the oil tank in the condenser as in Patent Document 2, the oil tank is stopped for a long time at a room temperature of 20 ° C. and a lubricating oil tank temperature of 55 ° C., and even if the refrigerant concentration of the lubricating oil is 10%, Since the dew point of the condenser and oil tank after start-up settles at about 35 ° C., the concentration of the lubricating oil rises to about 20%, there is no fear of forming, and the start-up time can be greatly shortened.

Of the compressor, condenser, and evaporator, which are the main components of the compression refrigerator, the evaporator is usually disposed at the lowest position. In the compression refrigerator arranged in this way, if the refrigerant is transferred from the evaporator to the oil concentrator, and if the pump is used to move the refrigerant having a high oil concentration from the oil concentrator to the oil tank, The pushing head against the pump is insufficient and cavitation occurs. In order to prevent this cavitation, it is necessary to raise the position of the evaporator, which increases the overall height of the compression refrigerator. When the refrigerant of the condenser is used for cooling the electric motor that drives the compressor, the position of the condenser is high and the pushing head can be secured, and when it cannot be secured (when pushing is insufficient), the suction section A supercooler is provided, and the suction liquid can be cooled with a refrigerant at the evaporator temperature to prevent cavitation. Even if the pump is used for moving the refrigerant in the evaporator, there is no lower temperature in the refrigerator, and a small refrigerator serving as a cooling heat source is necessary to make the supercooling effective.
Japanese Utility Model Publication No. 58-22064 Japanese Patent Application Laid-Open No. 10-300290

  The present invention has been made in view of the above points. The present invention recovers (concentrates) lubricating oil from a refrigerant liquid in an evaporation system in a refrigerator in which a lubricating oil tank is pressure-equalized in an evaporator or an economizer. Return to the lubricating oil tank, especially when the liquid level of the lubricating oil tank is higher than the position of the oil concentrator, or even when the lubricating oil tank pressure is higher than the pressure of the oil concentrator. It is an object of the present invention to provide a compression type refrigerator that can be moved (returned) to a lubricating oil tank, and an operation method thereof.

In order to solve the above problems, a compression refrigerator according to the present invention includes two systems, a high pressure side and a low pressure side, which are connected to a compressor, a condenser, and a refrigerant pipe through which an evaporator is circulated. A compressor of both refrigeration cycle systems is driven by a single motor, and the motor is cooled by a refrigerant of a high-pressure side refrigeration cycle system, and a lubricating oil tank is provided in which lubricating oil for lubricating the compressor bearings is stored. And a lubricating oil circulation system for supplying lubricating oil in the lubricating oil tank to the bearing with one oil circulation pump and returning the lubricating oil lubricated to the bearing to the lubricating oil tank, and further comprising a low-pressure side refrigeration cycle system The evaporator and the high-pressure side refrigeration cycle evaporator were connected by a pipe, and an open / close valve was provided on the pipe to adjust the liquid level of both evaporators to approximately the same level, thereby moving to the high-pressure side refrigeration cycle system. Refrigerant refrigerant on the low-pressure side The gas phase part in the lubricating oil tank and the gas phase part of the low-pressure equipment of the high-pressure side refrigeration cycle system are connected by a pressure equalizing pipe, and the evaporator of the low-pressure side refrigeration cycle system is connected by a pipe with a switching valve. An oil concentrator for concentrating the lubricating oil is provided, the lubricating oil tank and the oil concentrator are connected by a liquid return pipe, an open / close valve is provided in the liquid return pipe, and the gas phase part of the oil concentrator is refrigerated on the low pressure side. It is connected to a suction portion of a cycle type evaporator or compressor by a pipe, and an on-off valve is provided in the pipe.

The compression type refrigerator according to the present invention includes a compressor, a condenser and, e two systems Bei high pressure side and low pressure side refrigeration cycle system the evaporator connected by refrigerant piping in which the refrigerant is circulated, both the refrigeration cycle A compressor is driven by a single motor, the motor is cooled by a refrigerant in a high-pressure side refrigeration cycle system, and a lubricating oil tank is provided in which lubricating oil for lubricating the bearings of the compressor is stored. one line Bei example, further low-pressure side refrigeration cycle system evaporator lubricating oil circulation system for returning the lubricating oil tank lubricating oil lubricating the bearings is supplied to the bearing at one oil circulation pump lubricating oil in the tank And the high-pressure side refrigeration cycle system evaporator are connected by piping, and an open / close valve is provided in the piping to adjust the liquid level of both evaporators to substantially the same level. back to the low pressure side of the refrigeration cycle system, Jun Connect the gas phase section in the oil tank to the gas phase section of the low-pressure equipment of the high-pressure side refrigeration cycle system with a pressure equalizing pipe, and concentrate the lubricating oil connected to the evaporator of the low-pressure side refrigeration cycle system and piping with a switching valve. An oil concentrator, a lubricating oil tank and an oil concentrator are connected by a liquid return pipe, an open / close valve is provided in the liquid return pipe, and a gas phase portion of the oil concentrator is connected to an evaporator of a low-pressure side refrigeration cycle system or Connect the pipe to the suction part of the compressor, provide an open / close valve in the pipe, and connect the oil concentrator and the equipment whose pressure is higher than the pressure of the equipment connected by the pipe to the gas phase part of the lubricating oil tank. , characterized in that a closing valve in the pipe.

  Further, according to the present invention, in the above-described compression type refrigerator, the oil concentrator is provided with a concentration detecting means for detecting the concentration of oil, and when the completion of oil concentration is detected by the output of the concentration detecting means, the liquid in the oil concentrator is discharged. Control means for moving to the lubricating oil tank is provided.

  Further, the present invention provides the above-described compression type refrigerator, wherein the concentration detecting means detects the temperature of the solution with a temperature sensor that detects the dew point of the solution and the temperature of the solution, or a vapor pressure sensor that detects the vapor pressure of the oil concentrator. It is a temperature sensor which performs.

  Further, the present invention is characterized in that, in the above-described compression refrigerator, at least one of taking in and out of the liquid from the oil concentrator is performed by detecting the liquid level of the oil concentrator.

  Further, the present invention is characterized in that, in the compression type refrigerator, at least one of the withdrawal and withdrawal of the liquid from the oil concentrator is performed based on the elapsed time of the withdrawal and entry.

The present invention also relates to a method for operating a compression refrigeration machine for transferring a lubricating oil concentrated solution in an oil concentrator in the compression refrigeration machine to a lubricating oil tank, wherein the refrigerant containing the lubricating oil in the oil concentrator After completion of the concentration of the lubricating oil by heating, the concentrated lubricating oil solution is transferred to the lubricating oil tank by the pressure in the oil concentrator that is increased by the refrigerant vapor evaporated and accumulated in the oil concentrator.

  The present invention also relates to a method for operating a compression refrigeration machine for transferring a lubricating oil concentrated solution in an oil concentrator in the compression refrigeration machine to a lubricating oil tank, wherein the refrigerant containing the lubricating oil in the oil concentrator After completion of concentration of the lubricating oil by heating, the pressure of the equipment higher than the pressure of the equipment connected to the gas phase part of the lubricating oil tank by piping is introduced, and the lubricating oil concentrated solution is transferred to the lubricating oil tank at this pressure. Features.

  According to the present invention, in a refrigerator where the lubricating oil tank is pressure-equalized to a pressure device (evaporator or economizer) lower than the condenser pressure, the lubricating oil is concentrated and recovered from the refrigerant liquid of the evaporation system and returned to the lubricating oil tank. In particular, even when the liquid level position of the lubricating oil tank is higher than the liquid level position of the oil concentrator, or even when the lubricating oil tank pressure is higher than the oil concentrator pressure, the lubricating oil efficiently concentrated and recovered is put into the lubricating oil tank. Can be returned.

[ First Reference Example ]
Reference examples and embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an overall schematic configuration of a compression refrigerator 1-1 as a first reference example of the present invention. A compression refrigerator 1-1 shown in FIG. 1 is a compression refrigerator having a vapor compression refrigeration cycle, and includes a closed system in which a refrigerant is sealed.

  This compression refrigerator 1-1 includes an evaporator 11, a compressor (here, a two-stage compressor) 13, a condenser 17, and an economizer 18. The evaporator 11 and the compressor 13 are connected by a refrigerant pipe 21a. The compressor 13 and the condenser 17 are connected by a refrigerant pipe 21b, the condenser 17 and the economizer 18 are connected by a refrigerant pipe 21c, and the economizer 18 and the evaporator 11 are connected by a refrigerant pipe 21d. The refrigerant pipe 21c is provided with an expansion valve 19a, and the refrigerant pipe 21d is provided with an expansion valve 19b.

  The compression refrigerator 1-1 is provided with a control device (control means) (not shown) to control the drive of the electric motor 15, and the drive control of various pumps and various devices described later. Further, as will be described in detail later, the shafts of the compressor 13 and the electric motor 15 are integrally formed, and are rotatably supported by bearings 23 and 23. In FIG. 1, the impeller 13a of the compressor 13 and the shaft of the rotor 15a (see FIG. 16) of the motor 15 are directly connected, but as shown in FIG. 5, the rotation of the rotor 15a is increased by a combination of gears. It is good also as a structure which accelerates with a speed machine and drives the impeller 13a. In that case, the gears constituting the gearbox are also lubricated with lubricating oil.

  FIG. 16 is a diagram showing details of the motor 15 and the bearings 23 and 23. The bearings 23 and 23 are disposed between one end of the shaft of the electric motor 15, the other end of the shaft of the electric motor 15, and the discharge side of the compressor 13. The bearings 23, 23 are surrounded by a bearing chamber 70 (arranged in the bearing chamber 70), and a rotor chamber 15 b in which a discharge side pressure portion (impeller rear side portion) of the compressor 13 and a rotor 15 a of the electric motor 15 are disposed. A labyrinth or a narrow gap L is arranged between them. In FIG. 1, the bearing chamber 70 (see FIG. 16) and the lubricating oil tank 25 are connected by a pressure equalizing pipe 71 in order to ensure the return of oil from the bearings 23, 23 to the lubricating oil tank 25.

  The lubricating oil tank 25 has a lubricating oil liquid level, the upper part of which is a gas phase part where refrigerant vapor is present, and the lower part is a liquid phase part where a solution in which the refrigerant is mixed with lubricating oil is present. An oil pump 27 is connected to the lower part of the lubricating oil tank 25, and a mixed solution of the lubricating oil and the refrigerant in the lubricating oil tank 25 is sent to the bearings 23 and 23 through the lubricating oil supply pipe 29a, and the bearing chamber 70 (see FIG. 16). Is returned to the lubricating oil tank 25 through the return pipe 29b. Further, as described above, the gas phase part of the lubricating oil tank 25 and the upper part (gas phase part) of the economizer 18 are connected to the pressure equalizing pipe 31, and the refrigerant vapor in the gas phase part of the lubricating oil tank 25 is supplied to the economizer 18. It has been introduced.

  A pump 35 is installed in a pipe 36 a branched from the refrigerant pipe 21 c and directed to the electric motor 15, and a pipe 34 a branched from the pipe 36 a on the downstream side of the pump 35 is an oil cooling unit disposed in the lubricating oil tank 25. Connected to a heat exchanger (heat exchanger) 33. A refrigerant flow rate adjustment valve is provided in the pipe 34a to adjust the oil temperature. When the pump 35 is started, a part of the refrigerant discharged from the outlet of the condenser 17 to the refrigerant pipe 21c is supplied to the oil cooler 33 and the electric motor 15, and after cooling both, the pipe 34b becomes steam. It is configured to return to the inlet side of the condenser 17 through the pipe 36b.

  The refrigerant liquid supplied to the electric motor 15 cools the electric motor 15 and then becomes steam and returns to the condenser 17 through the pipe 36b as described above. The refrigerant that cannot be evaporated is the rotor chamber 15b (see FIG. 16). ) Is returned to the refrigerant pipe 21c connected to the lower outlet of the condenser 17 through the pipe 36c.

  On the other hand, the lubricating oil is cooled by the refrigerant liquid from the condenser 17 in the oil cooler 33 in the lubricating oil tank 25. The refrigerant liquid evaporates and returns to the condenser 17 through the pipe 34b, and the amount of cooling heat is increased. It discharges to the condenser 17 (cooling water). The oil cooler 33 may be provided not in the lubricating oil tank 25 but in the lubricating oil supply pipe 29 a connected to the outlet of the oil pump 27. Furthermore, when the refrigerant enters the oil lubrication system from the refrigerant system, for example, when the refrigerant that has cooled the electric motor 15 enters the bearing chamber 70 (see FIG. 16), the refrigerant evaporates from the lubricating oil in the lubricating oil tank 25. If the lubricating oil is cooled and the cooling is sufficient, the oil cooler 33 can be omitted. The lubricating oil tank 25 is provided with an electric heater 24, and while the compression refrigerator 1-1 is stopped, the electric heater 24 maintains the oil temperature so as not to absorb the refrigerant, so that the refrigerant concentration in the lubricating oil is increased. Is kept low.

The compression refrigerator 1-1 includes oil recovery means for recovering oil from the refrigerant of the evaporator 11 and returning it to the lubricating oil tank 25. 26 is an oil concentrator, the upper is connected to the refrigerant pipe 21b connected to the discharge port of the compressor 13 by a pipe 49 having a valve V _8. Further, the oil concentrator 26 is provided with heating means 60 so that the condensed refrigerant is guided through the pipe 62 from the condenser 17 to the evaporator 11 so that the refrigerant containing the lubricating oil is heated and concentrated to increase the lubricating oil concentration. It has become. Oil recovery means comprises an oil concentrator 26 and the lubricating oil tank 25, oil concentrator 26 and the lubricating oil tank 25 is connected by a pipe 28 having a valve V _11, the gas phase portion of the lubricating oil tank 25 is economizer The pressure equalizing pipe 31 is connected to 18 gas phase portions. The refrigerant containing the oil in the evaporator 11 and the refrigerant containing the oil in the liquid pool part a1 of the suction part of the compressor 13 are introduced into the oil concentrator 26 and heated by the heating means 60. The refrigerant liquid in the solution in the concentrator 26 evaporates, and the lubricating oil is concentrated into a lubricating oil concentrated solution. The lubricating oil concentrated solution is moved from the oil concentrator 26 to the lubricating oil tank 25 to recover the lubricating oil in the refrigerant.

Transfer of the refrigerant liquid (refrigerant liquid containing lubricating oil) from the evaporation system (evaporator 11, liquid reservoir part a <b> 1 of the suction portion of the compressor 13) to the oil concentrator 26 opens the valve V <b> ₁₀ and opens the valve V <b> _{10. With} valve ₈ closed, valve V ₉ is opened and valve V ₃ is opened. At this time, the valve V ₁₁ is closed. Movement completion of refrigerant liquid into the oil concentrator 26 detects by detecting a predetermined high liquid level in the liquid level sensor 41, the valve V _9, closing the valve V _3. In this state, the solution containing the lubricating oil in the oil concentrator 26 (mixed solution of lubricating oil and refrigerant liquid) is heated. As a result, the refrigerant in the solution becomes steam and is expelled through the valve V ₁₀ to the suction portion of the compressor 13, resulting in a lubricating oil concentrated solution having a small amount of refrigerant, that is, having a high lubricating oil concentration. By detecting a predetermined middle liquid level of the liquid level sensor 41, it is possible to detect that the refrigerant in the oil concentrator 26 has decreased and the lubricating oil has been concentrated. Alternatively, the concentration of the lubricating oil may be detected based on the temperature of the solution and the concentration may be increased to a predetermined temperature to complete the concentration, or the degree of concentration may be estimated based on the elapsed time from the start of heating concentration.

After completion of the concentration, the valve V ₁₀ is closed and the valve V ₈ is opened, so that the discharge pressure (condenser pressure level) of the compressor 13 is applied to the oil concentrator 26 through the pipe 49. The valve V ₁₁ provided in the pipe 28 connecting the lubricating oil tank 25 is opened, and the lubricating oil concentrated solution in the oil concentrator 26 is moved to the lubricating oil tank 25 with the applied pressure. Movement completion of the lubricating oil concentrate solution into the lubricating oil tank 25 is detected by the liquid level sensor 41 detects a predetermined low liquid level, closing the valve V ₁₁ and a valve V _8. The movement completion of the solution into the lubricating oil tank 25 during the time or than this slightly longer time required to move the controlled may be (constant volume by the time opening a valve V _11, the valve opening the V _11). Thereafter, the process returns to the refrigerant transfer step from the evaporation system to the oil concentrator 26.

As described above, the solution (mixed solution of refrigerant and lubricating oil) accumulated in the liquid reservoir a1 of the suction section of the compressor 13 is stored in the liquid reservoir a1 during the refrigerant transfer process from the evaporation system to the oil concentrator 26. And the valve V ₃ provided in the pipe 45 connecting the oil concentrator 26 is opened and moved to the oil concentrator 26. The valve V ₁₀ is in the refrigerant moving step and the oil concentration step from the liquid reservoir portion a1 is open. A valve V ₁₀ ′ indicated by a broken line may be substituted for the valve V ₃ and the valve V ₁₀ . The operation of the valve V ₁₀ 'is the same as V ₁₀ .

  When the lubricating oil concentrated solution in the oil concentrator 26 is moved to the lubricating oil tank 25, the amount of gas discharged from the compressor 13 (refrigerant vapor amount) is several times the volume of the oil concentrator 26. Almost negligible. This is several tenths of the consumption of the discharge gas of the compressor 13 in the case of transfer by the ejector (calculated from the nozzle diameter of the ejector). When managing the movement of the solution by time, if the timing is shifted, the solution in the oil concentrator 26 is lost, and high-pressure steam may be blown out from the oil concentrator 26 to the lubricating oil tank 25. In order to prevent the float from floating, a structure that closes the outlet when the liquid level disappears or a float valve may be provided.

FIG. 2 is a diagram showing an overall schematic configuration example of the compression refrigerator 1-2 according to the present invention. The compression refrigerator 1-2 shown in FIG. 2 is greatly different from the compression refrigerator 1-1 shown in FIG. 1 in that the valves V ₈ and V ₁₀ ′ of the compression refrigerator 1-1 shown in FIG. The role is replaced by one three-way valve V ₁₂ , and the valve of the pipe 28 connecting the oil concentrator 26 and the lubricating oil tank 25 is changed to the check valve V ₁₃ instead of the on-off valve V ₁₁ . In addition, the liquid level sensor 41 of the oil concentrator 26 detects only the high liquid level, and the middle liquid level and the low liquid level are managed by managing the time. The function of each device is the same as that constituting the compression refrigerator 1-1 of FIG. Further, the refrigerant supply pipe to the heating means 60 of the oil concentrator 26 is omitted. In addition, the gas phase portion of the lubricating oil tank 25 and the gas phase portion of the economizer 18 are connected by the pressure equalizing pipe 31, and the lubricating oil tank 25 is pressure-equalized by the economizer 18. As shown by the pressure pipe 31 ′, the pressure may be equalized in the evaporator system (here, the refrigerant pipe 21 a connecting the evaporator 11 and the compressor 13). In this case, pressure equalization is not performed on the economizer 18.

Transfer of the lubricating oil concentrated solution in the oil concentrator 26 to the lubricating oil tank 25 is performed in the oil concentrator 26 by the operation of the three-way valve V ₁₂ after the completion of concentration, as in the case of the compression refrigerator 1-1. By applying the discharge pressure (condenser pressure level) of the compressor 13 through the pipe 49, the pressure in the oil concentrator 26 rises, and the pressure in the oil concentrator 26 passes through the check valve V ₁₃ and the pipe 28. The lubricating oil concentrated solution is moved to the lubricating oil tank 25.

[ Second Reference Example ]
FIG. 3 is a diagram showing an overall schematic configuration example of a compression refrigerator 1-3 as a second reference example of the present invention. This compression refrigerator 1-3 is similar to the compression refrigerator 1-1 shown in FIG. 1, the compressor 13 is a two-stage compressor, and an economizer 18 is provided in a refrigerant pipe connecting the condenser 17 and the evaporator 11. The economizer 18 and the evaporator 11 are connected by the refrigerant pipe 21d, and the gas phase portion of the lubricating oil tank 25 and the gas phase portion of the economizer 18 are connected by the pressure equalizing pipe 31, and the pressure of the lubricating oil tank 25 is equalized to the economizer 18. Pressure.

In the present compression refrigeration machine 1-3, oil is not recovered directly from the evaporator 11 but is recovered from the suction portion of the compressor 13. That is, the oil concentrator 26 is arranged below the liquid reservoir a1 of the suction portion of the compressor 13, and the liquid reservoir a1 and the oil concentrator 26 are connected by a pipe 45 having a valve V ₃ ′. By the opening and closing operation of ₃ ′, a solution obtained by mixing the lubricating oil and the refrigerant liquid collected in the liquid reservoir a1 can be introduced into the oil concentrator 26. Also connects the refrigerant pipe 21b connected to the upper and the discharge port of the compressor 13 of the oil concentrator 26 a pipe 49 provided with a valve V _8. A heating means 60 is disposed inside the oil concentrator 26, a condensed refrigerant liquid is guided from the condenser 17 through the pipe 62, and the mixed solution of the lubricating oil and the refrigerant in the oil concentrator 26 is heated and concentrated to obtain a lubricating oil concentration. Can be raised. The condensed refrigerant liquid from the condenser 17 that has heated the mixed solution flows into the evaporator 11.

After completion of concentration in the oil concentrator 26, the valve V ₃ ′ is closed and the valve V ₈ is opened, so that the discharge pressure (condenser pressure level) of the compressor 13 is applied to the oil concentrator 26 through the pipe 49. In this state, the valve V ₁₁ provided in the pipe 28 connecting the oil concentrator 26 and the lubricating oil tank 25 is opened, and the lubricating oil concentrated solution in the oil concentrator 26 is moved to the lubricating oil tank 25 with this applied pressure.

FIG. 4 is a diagram showing an overall schematic configuration example of the compression refrigerator 1-4 according to the present invention. That compression refrigerating machine 1-4 shown in FIG. 4 differs significantly from the compression refrigerating machine 13 shown in FIG. 3, the role of the valve V ₈ and valve V ₃ of the compression type refrigerator 1-3 of FIG. 3 Is replaced with a single three-way valve V ₁₂ , the heating means 60 inside the oil concentrator 26 is eliminated, and the solution in the oil concentrator 26 is heated from the container surface with outside air. The operation of each device of the oil concentrator 26 is the same as that of the compression refrigerator 1-3 shown in FIG. The lubricating oil concentrated solution in the oil concentrator 26 is transferred to the lubricating oil tank 25 by applying the discharge pressure of the compressor 13 in the oil concentrator 26 and opening the valve V ₁₁ .

[ Third reference example ]
FIG. 5 is a diagram showing an overall schematic configuration example of a compression refrigerator 1-5 as a third reference example of the present invention. The point that this compression type refrigerator 1-5 differs from the compression type refrigerator 1-1 shown in FIG. 1 is that a speed increaser 22 configured by a combination of gears is provided between the compressor 13 and the electric motor 15. The lubricating oil tank 25 is integrated with the gear box 32, and an oil pump 27 is provided below the lubricating oil tank 25. The upper portion (gas phase portion) of the economizer 18 is connected to the inside of the gear box 32 by a pressure equalizing pipe 31, and the pressure in the gas phase portion of the lubricating oil tank 25 integrated with the gear box 32 is equalized to the economizer 18. Transfer of the refrigerant liquid containing the lubricating oil in the liquid reservoir a1 of the compressor 13 to the oil concentrator 26, transfer of the refrigerant liquid containing the lubricating oil of the evaporator 11 to the oil concentrator 26, and lubrication in the oil concentrator 26. The heating and oil concentration of the oil and the transfer of the lubricating oil concentrated solution to the lubricating oil tank 25 are the same as those in the compression refrigerator 1-1, and therefore the description thereof is omitted.

  FIG. 6 is a diagram illustrating an overall schematic configuration example of the compression refrigerator 1-6 according to the present invention. The compression refrigerator 1-6 shown in FIG. 6 is different from the compression refrigerator 1-5 shown in FIG. 5 in that the compressor 13 is a single stage and the pressure of the lubricating oil tank 25 is not provided without providing the economizer 18. Is equalized in the evaporator 11. That is, the upper part (vapor phase part) of the evaporator 11 and the inside of the gear box 32 are connected by a pipe 63 as a pressure equalizing pipe, and the vapor pressure of the lubricating oil tank 25 is connected via the gear box 32 and the pipe 63 to the evaporator 11. The pressure is equalized in the gas phase. Transfer of the refrigerant liquid containing the lubricating oil in the liquid reservoir a1 of the compressor 13 to the oil concentrator 26, transfer of the refrigerant liquid containing the lubricating oil of the evaporator 11 to the oil concentrator 26, and lubrication in the oil concentrator 26. The heating and oil concentration of the oil and the transfer of the lubricating oil concentrated solution to the lubricating oil tank 25 are the same as those in the compression refrigerator 1-1, and therefore the description thereof is omitted.

[ First Embodiment ]
FIG. 7 is a diagram illustrating an overall schematic configuration example of the compression refrigerator 1-7 as the first embodiment of the present invention. The present compression refrigeration machine 1-7 is a compression refrigeration machine provided with a refrigeration cycle duplicated by two closed systems enclosing a refrigerant.

  This compression refrigerator 1-7 includes a low-pressure evaporator 11-1, a high-pressure evaporator 11-2, a low-pressure compressor 13-1, a high-pressure compressor 13-2, a low-pressure condenser 17-1, and a high-pressure condenser 17-. 2. A low-pressure economizer 18-1 and a high-pressure economizer 18-2 are provided and connected by refrigerant piping. That is, the low-pressure evaporator 11-1 and the low-pressure compressor 13-1 are connected by the refrigerant pipe 21-1a, and the low-pressure compressor 13-1 and the low-pressure condenser 17-1 are connected by the refrigerant pipe 21-1b, and the low-pressure condensation is performed. 17-1 and low pressure economizer 18-1 are connected by refrigerant piping 21-1c, low pressure economizer 18-1 and low pressure evaporator 11-1 are connected by refrigerant piping 21-d, and high pressure evaporator 11-2 and high pressure are connected. The compressor 13-2 is connected by a refrigerant pipe 21-2a, the high pressure compressor 13-2 and the high pressure condenser 17-2 are connected by a refrigerant pipe 21-2b, and the high pressure condenser 17-2 and the high pressure economizer 18-2 are connected. Are connected by a refrigerant pipe 21-2c, and a high-pressure economizer 18-2 and a high-pressure evaporator 11-2 are connected by a refrigerant pipe 21-2d to form a duplex refrigeration cycle.

  The electric motor 15, the lubricating oil tank 25, the oil pump 27, the oil concentrator 26, and the like are shared by both refrigeration cycles. Cooling water 102 is supplied in series to the two condensers, that is, the low-pressure condenser 17-1 and the high-pressure condenser 17-2, and similarly to the two low-pressure evaporators 11-1 and 11-2. Is supplied with cold water 101 in series. The refrigerant liquid from the high pressure condenser 17-2 is supplied to the electric motor 15 through the pipe 36a by the pump 35, and the rotor chamber 15b (see FIG. 16) is a gas phase part of the high pressure condenser 17-2 on the outlet side of the cooling water 102. The pressure of the lubricating oil tank 25 is equalized by the high pressure economizer 18-2 on the high pressure refrigeration cycle side via the pressure equalizing pipe 31.

Since the back side pressure of the impeller 13a of the low pressure compressor 13-1 and the high pressure compressor 13-2 is higher than the pressure in the bearing chamber 70 (see FIG. 16) that is equalized by the high pressure economizer 18-2, the labyrinth is used. The refrigerant leaks. The refrigerant that has entered the bearing chamber 70 returns to the lubricating oil tank 25 together with the lubricating oil. Since the lubricating oil tank 25 is connected to the high-pressure refrigeration cycle side, the refrigerant flowing into the bearing chamber 70 from the back side of the impeller 13a of the low-pressure compressor 13-1 of the low-pressure refrigeration cycle moves to the high-pressure refrigeration cycle side. become. That is, the refrigerant moves from the low pressure refrigeration cycle to the high pressure refrigeration cycle. To return the moving refrigerant, connect the high pressure evaporator 11-2 and the low pressure evaporator 11-1 piping 66 having a valve V _6, the liquid level of the high-pressure evaporator 11-2 and the low pressure evaporator 11 The level is adjusted to approximately the same level. A liquid level sensor for detecting the liquid level is not shown.

In the high pressure evaporator 11-2 and the low pressure evaporator 11-1, there is a refrigerant liquid containing a small amount of lubricating oil leaking from the lubricating oil system, and the oil concentration in the evaporator increases from the bottom toward the liquid level. Therefore, the liquid is taken out from the relatively upper part of the high-pressure evaporator 11-2, returned to the low-pressure evaporator 11-1, and further the refrigerant liquid is introduced into the oil concentrator 26 from the relatively upper part of the low-pressure evaporator 11-1. The lubricating oil is concentrated to obtain a lubricating oil concentrate, and the lubricating oil concentrated solution is returned to the lubricating oil tank 25. The refrigerant vapor generated when the lubricating oil concentrate with oil condenser 26, via a valve V ₂₀ and the pipe 46 is discharged to the suction of the low pressure compressor 13-1 of the low pressure refrigeration cycle side to take pressure equalization ing. Here, it is assumed that the refrigerant moves from the low-pressure refrigeration cycle side to the high-pressure refrigeration cycle side. However, in order to ensure the moving direction of the refrigerant, for example, although not shown, the low-pressure economizer 18-1 and the high-pressure refrigeration cycle are omitted. The evaporator 11-2 may be connected by a pipe having a valve, and the valve may be adjusted manually or automatically.

A specific oil concentration recovery process will be described below. The valve V ₁₁ , the valve V ₈ are closed, the valve V ₂₀ is opened, the valve V ₉ is further opened, and the refrigerant containing the lubricating oil of the low-pressure evaporator 11-1 is introduced into the oil concentrator 26. closing the valve V ₉ when detecting a predetermined high liquid level. Next, the valve V _3-1 is opened for a predetermined time, and the liquid containing the lubricating oil in the liquid reservoir part a1-1 of the suction part of the compressor 13-1 on the low-pressure refrigeration cycle side is introduced into the oil concentrator 26. V _3-2 is opened for a predetermined time, and the liquid containing the lubricating oil in the liquid reservoir a1-2 of the compressor 13-2 on the high-pressure refrigeration cycle side is also introduced into the oil concentrator 26 (liquid reservoir a1-1, liquid Although the illustration of the amount of liquid from the reservoir a1-2 is also omitted, it may be managed by a liquid level sensor). When the refrigerant liquid containing the lubricating oil in the oil concentrator 26 is heated by the heater 61 with the valves V ₉ , V _3-1 and V _3-2 closed and the valve V ₂₀ opened, the refrigerant evaporates. The lubricating oil will be concentrated.

Detecting the completion concentrated by detecting a predetermined low liquid level in the liquid level sensor 41 closes the valve V _20. After completion of the concentration, the valve V ₈ is opened, the inside of the oil concentrator 26 is pressurized with the internal pressure of the gas phase of the high-pressure condenser 17-2, the valve V ₁₁ is also opened, and the lubricating oil concentration in which the lubricating oil in the oil concentrator 26 is concentrated. The solution is sent out to the lubricating oil tank 25. After a predetermined time has elapsed, the valve V ₁₁ is closed to complete the return of the solution to the lubricating oil tank 25. Completion of the return of the solution is not time management, and the liquid level sensor 41 may be used. These lubricating oil concentration and recovery steps are repeated during the operation of the compression type refrigerator 1-7. When the present invention is applied to a compression refrigeration machine of a double refrigeration cycle, various modifications exist such as connecting the oil concentrator 26, the lubricating oil tank 25, etc. to the low pressure cycle side or the high pressure cycle side, The configuration is not limited to that shown in FIG.

[ Second Embodiment ]
FIG. 8 is a diagram illustrating an overall schematic configuration example of a compression refrigerator 1-8 as a second embodiment of the present invention. The compression type refrigerator 1-8 is a compression type refrigerator including a refrigeration cycle duplicated by two closed systems in which a refrigerant is enclosed, like the compression refrigerator 1-7 shown in FIG. The main difference between the compression type refrigerator 1-8 and the compression type refrigerator 1-7 shown in FIG. 7 is that the lubricating oil is recovered from the evaporator system, and the liquid reservoir in the suction portion of the low pressure compressor 13-1. and only the parts a1-1 and suction part of the liquid reservoir portion a1-2 of the high pressure compressor 13-2, i.e. liquid reservoir portion a1-1 a pipe 45 having a valve V _3-1 between the oil concentrator 26 connect -1, between the liquid reservoir portion a1-2 oil concentrator 26 connected by a pipe 45-2 having a valve V _3-2, the lubricating oil collected from the refrigerant of the low pressure evaporator 11 - It is a point that is not done. Further, the electric motor 15 is cooled by the refrigerant on the low-pressure refrigeration cycle side, that is, the refrigerant from the low-pressure condenser 17-1 is supplied to the electric motor 15 through the pipe 36a by the pump 35, and the electric motor 15 is cooled to become steam. The refrigerant is returned to the low pressure condenser 17-1 through the pipe 36b, and the gas phase portion of the lubricating oil tank 25 is connected to the gas phase portion of the low pressure economizer 18-1 of the low pressure refrigeration cycle system by the pressure equalizing pipe 31. The pressure equalization destination is a low-pressure economizer 18-1.

In the case where the compression refrigerator 1-8 is configured as described above, the refrigerant has more low-pressure cycle side and lacks high-pressure cycle side, so in order to eliminate this refrigerant imbalance, the low-pressure evaporator 11-1 the upstream side of the expansion valve 19b-1 and the high-pressure evaporator 11-2 is connected by a pipe 67 having a valve V _16, the liquid level between the low-pressure evaporator 11-1 and the high-pressure evaporator 11 - substantially the same So that it can be adjusted. The liquid level sensor is not shown.

A specific oil concentration recovery process will be described below. Close the valves V _3-1 and V _3-2 . The valve V ₈ is opened, then the valve V _3-1 is opened for a predetermined time, and the refrigerant liquid (refrigerant liquid mixed with lubricating oil) in the liquid reservoir a1-1 of the suction part of the low-pressure compressor 13-1 is oil concentrated. Move to 26 and close valve V _3-1 . Thereafter, the valve V _3-2 is opened for a predetermined time, and the refrigerant liquid (refrigerant liquid mixed with lubricating oil) in the liquid reservoir a1-2 of the suction part of the high-pressure compressor 13-2 is moved to the oil concentrator 26. Close V _3-2 . In this state, by heating the mixed solution of the lubricating oil and the refrigerant in the oil concentrator 26, the refrigerant liquid is evaporated and the lubricating oil is concentrated.

Evaporated refrigerant by opening the valve V _14, passes through the refrigerant pipe 21-1a, it is guided to the suction portion of the low pressure compressor 13-1. After a predetermined time has passed, the valve V ₁₄ is closed as the completion of concentration, and the process moves to the step of moving the solution in which the lubricating oil is concentrated from the oil concentrator 26 to the lubricating oil tank 25. In this solution movement, first, the valve V ₈ is opened, the refrigerant vapor of the low-pressure condenser 17-1 is introduced into the oil concentrator 26 through the pipe 49, the inside of the oil concentrator 26 is pressurized with the refrigerant vapor, and the valve V ₁₁ is open, a lubricating oil concentrate solution in the oil concentrator 26 is moved to the lubricating oil tank 25, the valve V ₁₁ as movement completion after a predetermined time, closing the valve V _8. These steps are repeated during the operation of the present compression refrigerator 1-8. The order in which the valves V _3-1 and V _3-2 are opened may be changed. Further, omitting the valve V _14, it may be also used that act on the valve V _3-1.

[ Fourth Reference Example ]
FIG. 9 is a diagram showing an overall schematic configuration of a compression refrigerator 1-9 as a fourth reference example of the present invention. This compression type refrigerator 1-9 is an example in which the lubricating oil tank 25 is above the oil concentrator 26, like the compression refrigerator 1-5 shown in FIG. The lubricating oil tank 25 is disposed between the compressor 13 and the electric motor 15 and is provided below the gear box 32 that houses the speed increaser 22. The electric motor 15 is cooled by a refrigerant having a condenser pressure or an economizer pressure (not shown), and the pressure in the lubricating oil tank 25 is higher than the pressure in the evaporator 11. The valve V ₁ is closed, the valve V ₃ is closed, the valve V ₇ is opened, and the pressure in the oil concentrator 26 is made substantially the same as that of the lubricating oil tank 25 to which the solution is moved. The only necessary head is the position head.

The valve V ₃ is opened and the lubricating oil containing the refrigerant in the liquid reservoir a1 of the compressor 13 is introduced into the oil concentrator 26. The valve V ₉ is further opened to supply the refrigerant liquid containing the lubricating oil in the evaporator 11 to the oil concentrator. 26. Then valve V ₉ closed, the V ₁ open, the valve V ₇ is closed, the refrigerant liquid in the oil concentrator 26 (mixed solution of lubricating oil and refrigerant liquid) heated by the heating means 60, evaporating the refrigerant liquid To concentrate the lubricant. The evaporated refrigerant vapor is expelled to the suction portion of the compressor 13 through the valve V ₁ and the pipe 46. After concentration is completed, by closing valve V _1, the refrigerant vapor evaporated in the oil concentrator 26 is accumulated, the inner pressure of the oil concentrator 26 rises. When this internal pressure reaches a predetermined pressure, the concentrated lubricating oil concentrate in the oil concentrator 26 is pumped to the lubricating oil tank 25 by this internal pressure by opening the valve V ₁₁ . In addition, the concentration detection of the lubricating oil is performed by detecting the liquid level by the liquid level sensor, detecting the temperature of the solution, elapse of time from the start of heating concentration, and the like as described above.

[ Fifth Reference Example ]
FIG. 10 is a diagram showing an overall schematic configuration of a compression refrigerator 1-10 as a fifth reference example of the present invention. The compression refrigerator 1-10 is provided with a transfer tank 55 in the compression refrigerator 1-9 shown in FIG. 9, and operates the valve V ₁₁ ′, which is a three-way valve, for transferring the solution in the oil concentrator 26. In this example, the tank 55 is moved. By closing the valve V ₃ and operating the three-way valve V _{4 to} connect the pipe 63 to the gas phase part of the oil concentrator 26, the oil concentrator 26 is substantially the same as the lubricating oil tank 25 to which the solution is moved. By setting the pressure, only the position head is required for movement.

The valve V ₃ is opened, the lubricating oil containing the refrigerant in the liquid reservoir a 1 of the compressor 13 is introduced into the oil concentrator 26, and the valve V ₉ is opened to concentrate the refrigerant liquid containing the lubricating oil in the evaporator 11. It is introduced into the vessel 26. Thereafter, the valve V ₃ is closed, and the refrigerant liquid in the oil concentrator 26 is heated by the heating means 60 to concentrate the lubricating oil. After completion of the concentration, if the communication between the gas phase portion of the oil concentrator 26 and the pipe 63 is blocked by the three-way valve V ₄ , the evaporated refrigerant vapor accumulates in the oil concentrator 26, so that the internal pressure of the oil concentrator 26 increases. To go. When the internal pressure reaches a predetermined pressure, the three-way valve V ₁₁ ′ communicates the pipe 66 with the liquid layer portion in the oil concentrator 26, thereby concentrating the concentrated lubricating oil concentrate through the pipe 66 by this internal pressure. Pump to 25. In addition, the concentration detection of the lubricating oil is performed by detecting the liquid level by the liquid level sensor, detecting the temperature of the solution, elapse of time from the start of heating concentration, and the like as described above.

In the compression refrigerator of each of the above embodiments and reference examples , the oil is transferred from the place (A) (see FIGS. 18 and 19) where the lubricating oil to be collected exists to the oil concentrator 26 (depending on the position head). The refrigerant vapor evaporated by the oil concentrator 26 is guided to an evaporation system (evaporator 11 or a suction portion of the compressor 13). The pressure equalization destination of the lubricating oil tank 25 is (B) the evaporator 11 or the economizer 18 (see FIGS. 18 and 19), and the pressure source (C) condenser 17 or the economizer 18 (see FIG. 18) in the oil concentrator 26. 19 (see FIG. 19), and the lubricating oil concentrated solution having a high lubricating oil concentration concentrated in the oil concentrator 26 is moved to the lubricating oil tank 25. Here, (A), (B), and (C) are as follows.

(A): The place (apparatus) where the refrigerant mixed with the lubricating oil to be collected exists is the liquid reservoir a1 of the suction portion of the evaporator 11 and the compressor 13 (however, gas-liquid separation in the evaporator 11) If the refrigerant mist does not fly from the evaporator 11 to the compressor 13, the refrigerant mixed with lubricating oil does not accumulate in the liquid reservoir a <b> 1 of the suction portion of the compressor 13).
(B): The pressure equalization destination of the lubricating oil tank 25 is the evaporation system (the evaporator 11 or the suction portion of the compressor 13) or the economizer 18.
(C): Pressure is applied to the solution mixed with oil and refrigerant in the oil concentrator 26 and moved to the lubricating oil tank 25. The pressure source is the condenser 17 or the economizer 18 (however, the pressure equalization of the lubricating oil tank 25) This is the case of the evaporator 11).

  FIG. 18 shows a basic combination example when the pressure equalization tip (B) is an evaporator, and FIG. 19 shows a basic combination example when the pressure equalization tip (B) is an economizer. In FIG. 18 and FIG. 19, “suction liquid reservoir” is an abbreviation for the liquid reservoir a <b> 1 of the suction portion of the compressor 13. As shown in the figure, when the pressure equalization tip (B) is an evaporator, there is a combination of case 1 to case 6, and when the pressure equalization tip (B) is, there is a combination of case 7 to case 9.

The location (A) where the refrigerant liquid mixed with the lubricating oil to be collected exists (evaporator 11, liquid reservoir a1,) and the pipe connecting the oil concentrator 26, evaporating the refrigerant vapor evaporated in the oil concentrator 26 A pipe leading to the system (from the evaporator 11 to the liquid reservoir a1), a pipe leading the concentrated solution of the lubricating oil in the oil concentrator 26 to the lubricating oil tank 25, and a pressure source (condenser 17, economizer) to the oil concentrator 26 18) Valves are respectively provided in the pipes for guiding the pressure, and these pipes are turned ON / OFF by operating the valves. However, these on-off valves are not all necessary. Further, for example, the valve V ₃ provided in the pipe connecting the liquid reservoir part a 1 and the oil concentrator 26 and the V ₁₀ provided in the pipe connecting the suction part of the compressor 13 and the oil concentrator 26 are combined. (Refer to FIG. 1) Alternatively, the valve V ₁₁ provided in the pipe for sending the solution of the oil concentrator 26 to the lubricating oil tank 25 may be a check valve V ₁₃ (see FIG. 2).

The following are typical examples of valves that are turned ON / OFF in the lubricant recovery process.
(1) Pressurization of the oil concentrator 26 is stopped (valve V ₈ : closed), and movement of the solution from the oil concentrator 26 to the lubricating oil tank 25 is stopped (valve V ₁₁ : closed). 26 is equalized to the pressure level of the evaporator 11 (valves V ₁₀ , V ₁₄ , V ₂₀ : opened), and the suction portion of the evaporator 11 or the compressor 13 and the oil concentrator 26 are communicated (valve V ₉ : The valve V _{3 is} opened), and the refrigerant containing lubricating oil is introduced into the oil concentrator 26.
(2) Stop the introduction of the solution into the oil concentrator 26 (valve V ₉ : closed, valve V ₃ : closed) and other valves maintain the state of (1) (valves V ₁₀ , V ₁₄ , V ₂₀ : open) , Valve V ₁₁ : closed, valve V ₈ : closed), the refrigerant in the oil concentrator 26 is evaporated and the lubricating oil is concentrated. (If mist accumulated in the suction portion of the liquid reservoir portion a1 of the compressor 13 is small, it may be left valve V ₃ is opened.)

(3) After completion of the concentration of the lubricating oil, the piping for leading the refrigerant vapor evaporated from the oil concentrator 26 to the evaporator pressure level is shut off (valve V ₂₀ : closed), and the refrigerant vapor from the condenser 17 as the pressurizing source Is started (valve V ₈ : open). Pressure and also substantially simultaneously opening valve V _11. (Note that (if the valve V ₉ is opened in 2), (3) in closed together with the valve _{V 10, V 14, V 20} .)
(4) While pressurizing the gas phase part of the oil concentrator 26 (valve V ₈ : open), the solution in the oil concentrator 26 is moved into the lubricating oil tank 25 (valve V ₁₁ : open).
(5) After the solution transfer in the oil concentrator 26 is completed (valve V ₁₁ : closed), pressurization is stopped (valve V ₈ : closed), and then the valves V ₁₀ , V ₁₄ and V ₂₀ are opened (1) Return to.
A summary of the above is shown in FIG.

  By bringing the oil concentrator 26 to the evaporator pressure level and heating the solution in the oil concentrator 26 (mixed solution of refrigerant liquid and lubricating oil), the refrigerant evaporates and the lubricating oil concentration increases. Various heat sources can be applied as the heat source used for the heat concentration as follows. However, the higher the temperature of the heat source, the higher the lubricating oil concentration can be. For example, as can be seen from FIG. 17, when the dew point of the oil concentrator 26 is 5 ° C., a refrigerant concentration of 20% (lubricating oil concentration of 80%) can be obtained by raising the mixed solution to 16 ° C. When the temperature is raised, a refrigerant concentration of 10% (lubricating oil concentration of 90%) is obtained, and when the mixed solution is heated to 56 ° C., a refrigerant concentration of 5% (lubricating oil concentration of 95%) is obtained.

(A) An example in which the solution in the oil concentrator 26 is heated with the refrigerant from the condenser 17 and then the refrigerant is returned to the evaporator 11 is the compression type refrigerator 1-1 shown in FIG. May be refrigerant liquid or refrigerant vapor).
(B) The solution in the oil concentrator 26 is heated with the refrigerant from the condenser 17 and then returned to the economizer 18 (the refrigerant introduced here may be refrigerant liquid, refrigerant vapor, or gas-liquid two-phase. The return destination of the refrigerant after heating may be the evaporator 11).
As a heating source of similar temperature level,
Heat with the cooling water 102 of the condenser 17.
Heat to the inlet side of the evaporator 11 with inflowing cold water.
(C) Heat with the refrigerant from the economizer 18 and then return to the evaporator 11.
(D) Heat with lubricating oil supplied to the bearing 23 and the like.
(E) Heat with the electric heater 24.
(F) The refrigerant in the oil concentrator 26 can be concentrated by being exposed to the evaporator pressure level for a long time with outside air (no special heat exchanger or the like is provided). It has become.

  The concentration of the lubricating oil in the oil concentrator 26 in which the gas phase portion is connected to the low pressure side (the evaporator 11 or the suction portion of the compressor 13) by piping is, for example, the refrigerant dew point (or vapor pressure), the lubricating oil and the refrigerant It can be calculated from the relationship with the temperature of the mixed solution. Usually, since the temperature of the evaporator 11 is substantially constant, the approximate temperature can be known from the solution temperature. However, in this method, it is necessary to consider the case where the refrigerant temperature has not fallen completely at the time of startup. For example, the concentration is not judged for several minutes after activation. Further, the concentration magnification can be known by the liquid level sensor 41 of the oil concentrator 26. It is also possible to manage the movement amount of the refrigerant containing the lubricating oil from the evaporator 11 at a high liquid level and manage the completion of concentration (concentration magnification reached) at a medium liquid level (or a low liquid level). Even if the concentration is not accurately detected, the rough concentration management can be performed during the time of exposure to the low pressure state.

  The lubricating oil concentrated solution can be moved from the oil concentrator 26 to the lubricating oil tank 25 using the pressure difference between the oil concentrator 26 that is the moving source and the lubricating oil tank 25 that is the moving destination. The lower liquid level of the oil concentrator 26 may be detected by the liquid level sensor 41 to detect the completion of movement, or the completion of movement may be estimated from the elapsed time from the start of movement. In addition, when managing by elapsed time, you may prevent a blow-through using a float valve etc.

[ Sixth Reference Example ]
In the compression refrigerator 1-1 having the configuration shown in FIG. 1, the refrigerant (containing lubricating oil) from the evaporation system (evaporator 11, liquid reservoir a <b> 1 of the suction portion of the compressor 13) to the oil concentrator 26 is contained. The transfer is performed with the valve V ₁₀ opened, the valve V ₉ opened, and the valve V ₃ opened. At this time, the valve V ₁₁ is kept closed. When the transfer of the solution (refrigerant liquid including lubricating oil) to the oil concentrator 26 is completed, the liquid level sensor 41 detects a predetermined high liquid level, and the valves V ₉ and V ₃ are closed when the transfer of the solution is completed. In this state, the solution in the oil concentrator 26 is heated, and the refrigerant becomes vapor and is expelled through the valve V ₁₀ to the suction portion of the compressor 13, so that the solution with reduced refrigerant, that is, lubrication with a high lubricating oil concentration. Become oil concentrated solution. The refrigerant in the oil concentrator 26 decreases, and the liquid level sensor 41 detects a predetermined middle liquid level to detect that the lubricating oil has been concentrated. Alternatively, the concentration of the lubricating oil may be detected based on the temperature of the solution, and the concentration may be completed by detecting that the temperature of the solution in the oil concentrator 26 has risen to a predetermined temperature. Further, the degree of concentration of the lubricating oil may be estimated from the elapsed time from the start of heating of the solution.

After concentration operations to complete by closing the valve V _10, the refrigerant vapor evaporated in the oil concentrator 26 is accumulated, the inner pressure of the oil concentrator 26 rises. When the predetermined pressure or temperature is reached, the valve V ₁₁ provided in the pipe 28 connecting the oil concentrator 26 and the lubricating oil tank 25 is opened, so that the internal lubricating oil concentration is increased by the pressure in the oil concentrator 26. The resulting concentrated lubricating oil solution moves into the lubricating oil tank 25. Further, the transfer completion to the lubricating oil tank 25 of the solution is detected by detecting detects a predetermined low liquid level in the liquid level sensor 41, closing the valve V ₁₁ Once turned movement completion. Completion of the transfer of the solution to the lubricating oil tank 25 may be controlled by the time when the valve V ₁₁ is open (for the time required to move a certain volume or for a little longer than this, the valve V ₁₁ Is open). After the solution completion of the movement from the oil concentrator 26 to the lubricating oil tank 25 by opening the valve V _10, returns to the refrigerant transfer process from the first evaporation system to the oil concentrator 26. Thus, by utilizing the increased internal pressure by heating, since the solution can also be moved to the lubricating oil tank 25 may be omitted piping 49 and the valve V _8.

The liquid (mixed solution in which the refrigerant liquid and the lubricating oil are mixed) accumulated in the liquid reservoir a1 of the suction section of the compressor 13 is, as described above, in the refrigerant transfer process from the evaporator system to the oil concentrator 26. The valve V ₃ provided in the pipe 45 connecting the oil concentrator 26 from the liquid reservoir a 1 is opened and moved to the oil concentrator 26. The valve V ₁₀ is moving step refrigerant containing lubricating oil from the liquid reservoir a1 moves open. A valve V ₁₀ ′ indicated by a broken line may be substituted for the valve V ₃ and the valve V ₁₀ . Operation of the valve V ₁₀ 'is the same as the valve V _10. Here, although the lubricating oil tank 25 is pressure-equalized by the economizer 18 by the pressure equalizing pipe 31, the pressure equalizing pipe 31 'is connected to the evaporation system as shown by the broken line in FIG. (In this case, pressure equalization to the economizer is not performed).

FIG. 11 is a diagram showing an overall schematic configuration of a compression refrigerator 1-11 as a sixth reference example of the present invention. In the present compression refrigeration machine 1-11, the compressor 13 is a two-stage compressor, and an economizer 18 is provided in a refrigerant pipe connecting the condenser 17 and the evaporator 11, that is, the condenser 17 and the economizer 18 are connected by a refrigerant pipe 21c. The economizer 18 and the evaporator 11 are connected by the refrigerant pipe 21d, and the gas phase portion of the lubricating oil tank 25 and the gas phase portion of the economizer 18 are connected by the pressure equalizing pipe 31, and the pressure in the lubricating oil tank 25 is controlled by the economizer 18. The pressure is even.

  An oil pump 27 is connected to the lower portion of the lubricating oil tank 25, and a mixed solution of the lubricating oil and the refrigerant liquid in the lubricating oil tank 25 is sent to the bearings 23 and 23 through the lubricating oil supply pipe 29a, and the bearing chamber 70 (see FIG. 16). ) To the lubricating oil tank 25 through the lubricating oil return pipe 29b. Further, the refrigerant vapor in the gas phase portion of the lubricating oil tank 25 is introduced into the upper portion (gas phase portion) of the economizer 18 through the pressure equalizing pipe 31.

  Note that a pump 35 is provided in a pipe 36 a branched from the refrigerant pipe 21 c and directed to the electric motor 15, and a pipe 34 a branched from the pipe 36 a on the downstream side of the pump 35 is an oil cooling unit disposed in the lubricating oil tank 25. Connected to a heat exchanger (heat exchanger) 33. If the pump 35 is started, a part of the refrigerant produced from the outlet of the condenser 17 to the refrigerant pipe 21c is supplied to the oil cooler 33 and the electric motor 13, and after both are cooled, it becomes refrigerant vapor and the pipe 34b. It is configured to pass back to the inlet side of the condenser 17. The refrigerant liquid supplied to the electric motor 15 cools the electric motor 15 and then becomes vapor and is returned to the condenser 17 through the pipe 36b. The refrigerant that has not been evaporated is returned to the rotor chamber (see FIG. 16). The refrigerant that has not been evaporated is returned from the lower part of the rotor chamber 15b to the refrigerant pipe 21c through the pipe 36c.

  On the other hand, the lubricating oil is cooled by the refrigerant liquid from the condenser 17 in the oil cooler 33 in the lubricating oil tank 25. The refrigerant liquid evaporates and returns to the condenser 17 through the pipe 34b, and the amount of cooling heat is increased. It discharges to the condenser 17 (cooling water). Note that the oil cooler 33 may be provided not in the lubricating oil tank 25 but in the lubricating oil supply pipe 29a by connecting to the outlet of the oil pump 27. Furthermore, when the refrigerant enters the oil lubrication system from the refrigerant system, for example, when the refrigerant that has cooled the electric motor 15 enters the bearing chamber 70 (see FIG. 16), the refrigerant evaporates from the lubricating oil in the lubricating oil tank 25. If the lubricating oil is cooled and the cooling is sufficient, the oil cooler 33 can be omitted. The lubricating oil tank 25 is provided with an electric heater 24, and while the compression refrigerator 1-11 is stopped, the electric heater 24 keeps the oil temperature at a predetermined value so as not to absorb the refrigerant. The refrigerant concentration inside is kept low.

Here, the oil concentrator 26 and the lubricating oil tank 25 constitute oil recovery means of the compression refrigeration machine 1-11. The oil concentrator 26 is provided with heating means 60, and the condensed refrigerant liquid is guided through the pipe 62 from the condenser 17 to the evaporator 11, and the mixed solution of the lubricating oil and the refrigerant liquid is heated to increase the lubricating oil concentration. It has become. The oil concentrator 26 and the lubricating oil tank 25 are connected by a pipe 28 having a check valve V _13, and the gas phase portion of the lubricating oil tank 25 is connected to the gas phase portion of the economizer 18 by a pressure equalizing pipe 31. The refrigerant liquid containing the oil in the evaporator 11 and the mixed solution of the lubricating oil and the refrigerant liquid in the liquid reservoir a1 of the suction part of the compressor 13 are introduced into the oil concentrator 26 and heated by the heating means 60. Accordingly, the solution in the oil concentrator 26 becomes a lubricating oil concentrated solution in which the lubricating oil is concentrated, and the lubricating oil concentrated solution is moved to the lubricating oil tank 25 to recover the lubricating oil in the refrigerant.

Transfer of the evaporation system (a mixed solution of the lubricating oil and refrigerant liquid) refrigerant liquid into the oil concentrator 26 from (the evaporator 11, the suction unit liquid reservoir a1 of the compressor 13) opens the valve V ₁₀ ', the valve carried out by opening the V _9. Completion of the refrigerant fluid movement into the oil concentrator 26 detects by detecting a predetermined high liquid level in the liquid level sensor 41, closing the valve V ₉ and the valve V ₁₀ '. In this state, the mixed solution of the lubricating oil and the refrigerant liquid in the oil concentrator 26 is heated by the heating means 60. By this heating, the refrigerant becomes vapor and is expelled through the valve V ₁₀ ′ to the suction portion of the compressor, and becomes a solution with a reduced amount of refrigerant, that is, a lubricating oil concentrated solution having a high lubricating oil concentration. Note that the concentration detection of the lubricating oil is performed by detecting the liquid level by the liquid level sensor, detecting the temperature of the solution, elapse of time from the start of heating concentration, and the like as described above.

By closing the valve V ₁₀ ′ after the completion of the concentration, the evaporated refrigerant vapor is accumulated in the oil concentrator 26, so that the internal pressure of the oil concentrator 26 increases. As the internal pressure rises, the lubricating oil concentrated solution in the oil concentrator 26 is pumped to the lubricating oil tank 25 through the check valve V ₁₃ and the pipe 28.

[ Seventh Reference Example ]
FIG. 12 is a diagram showing an overall schematic configuration of a compression refrigerator 1-12 as a seventh reference example of the present invention. This compression type refrigerator 1-12 has a compressor 13 as a two-stage compressor, and an economizer 18 is connected to a refrigerant pipe connecting the condenser 17 and the evaporator 11 as in the case of the compression refrigerator 1-11 shown in FIG. In other words, the condenser 17 and the economizer 18 are connected by the refrigerant pipe 21c, the economizer 18 and the evaporator 11 are connected by the refrigerant pipe 21d, and the upper part (gas phase part) of the lubricating oil tank 25 and the upper part of the economizer 18 (gas Are connected by a pressure equalizing pipe 31 to equalize the pressure in the lubricating oil tank 25 to the economizer 18.

In the present compression refrigeration machine 1-12, oil is not recovered directly from the refrigerant liquid in the evaporator 11, but is recovered from the suction portion of the compressor 13. That is, the oil concentrator 26 is disposed below the liquid reservoir portion a1 of the suction portion of the compressor 13, and the liquid reservoir portion a1 and the upper portion of the oil concentrator 26 are connected by a pipe 45 having a valve V ₃ ′. By opening and closing V ₃ ′, the mixed solution of the lubricating oil and the refrigerant liquid accumulated in the liquid reservoir a 1 can be introduced into the oil concentrator 26. In addition, a heating means 60 is provided inside the oil concentrator 26, a condensed refrigerant is guided from the condenser 17 through the pipe 62, and the mixed solution of the lubricating oil and the refrigerant liquid in the oil concentrator 26 is heated, and the refrigerant liquid The concentration of the lubricating oil is increased by evaporating the oil. The condensed refrigerant liquid from the condenser 17 that has heated the mixed solution flows into the evaporator 11.

After the concentration of the mixed solution in the oil concentrator 26 is completed, the refrigerant vapor evaporated in the oil concentrator 26 is accumulated by closing the valve V ₃ ′, so that the internal pressure of the oil concentrator 26 increases. When the internal pressure rises to a predetermined value, the valve V ₁₁ is opened to feed (move) the lubricating oil concentrated solution in the oil concentrator 26 to the lubricating oil tank 25 by this internal pressure. In addition, the concentration detection of the lubricating oil is performed by detecting the liquid level by the liquid level sensor, detecting the temperature of the solution, elapse of time from the start of heating concentration, and the like as described above.

FIG. 13: is a figure which shows the whole schematic structure of the compression refrigerator 1-13 as a 7th reference example of this invention. The main difference between this compression refrigerator 1-13 and the compression refrigerator 1-12 shown in FIG. 12 is that the heating means 60 in the oil concentrator 26 is removed, and the lubricating oil and refrigerant in the oil concentrator 26 are removed. The liquid mixed solution is heated by the outside air from the surface of the container. The mixed solution of the lubricating oil and the refrigerant liquid from the liquid reservoir a1 is introduced into the oil concentrator 26 and concentrated in the oil concentrator 26. The movement of the concentrated lubricating oil solution to the lubricating oil tank 25 is the same as that of the compression refrigerator 1-12 shown in FIG.

[ Eighth Reference Example ]
FIG. 14 is a diagram showing an overall schematic configuration of a compression refrigerator 1-14 as an eighth reference example of the present invention. In this compression refrigeration machine 1-14, the compressor 13 is a two-stage compressor, and an economizer 18 is provided in a refrigerant pipe connecting the condenser 17 and the evaporator 11, that is, the condenser 17 and the economizer 18 are connected by a refrigerant pipe 21c. The economizer 18 and the evaporator 11 are connected by a refrigerant pipe 21d. The lubricating oil tank 25 is integrated with the gear box 32, and an oil pump 27 is provided below the lubricating oil tank 25. The gas phase portion of the economizer 18 is connected to the inside of the gear box 32 by the pressure equalizing pipe 31, and the pressure of the lubricating oil tank 25 integrated with the gear box 32 is equalized to the economizer 18.

In the compression type refrigerator 1-14 having the above-described configuration, the valve V ₁₀ ′ is opened to introduce the mixed solution of the lubricating oil and the refrigerant liquid in the liquid reservoir a1 of the suction portion of the compressor 13 into the oil concentrator 26. V ₉ is opened and the refrigerant liquid containing the lubricating oil in the evaporator 11 is introduced into the oil concentrator 26. Completion of introduction is the same as described above, for example, by detecting the liquid level sensor 41 by detecting a predetermined high liquid level. After the introduction is completed, the valve V ₉ is closed, the condensed refrigerant liquid of the condenser 17 is introduced into the heating means 60 to heat the mixed solution, and the lubricating oil is concentrated to obtain a lubricating oil concentrated liquid. Concentration completion detection is the same as described above, for example, by detecting a predetermined middle liquid level with the liquid level sensor 41. By closing the valve V ₁₀ ′ after the completion of the concentration, the evaporated refrigerant vapor is accumulated in the oil concentrator 26, so that the internal pressure of the oil concentrator 26 increases. If this pressure rises to a predetermined value, by opening the valve V _11, lubricating oil concentrate solution in the oil concentrator 26 is pumped into the lubricating oil tank 25 by the internal pressure.

  FIG. 15 is a diagram showing an overall schematic configuration of the compression refrigerator 1-15 of the present invention. This compression refrigerator 1-15 differs from the compression refrigerator 1-14 shown in FIG. 14 in that the compressor 13 is a single stage and the pressure of the lubricating oil tank 25 is reduced without providing an economizer 18. 11 is equalized in the gas phase. That is, the vapor phase portion of the evaporator 11 and the inside of the gear box 32 are connected by a pipe 63 as a pressure equalizing pipe, and the pressure of the vapor phase portion of the lubricating oil tank 25 is connected to the gas in the evaporator 11 via the gear box 32 and the pipe 63. Equal pressure is applied to the phase. Introducing, heating, concentrating, and concentrating the concentrated lubricating oil of the refrigerant liquid containing the lubricating oil and the refrigerant liquid in the liquid reservoir a1 of the suction section of the compressor 13 and the lubricating oil from the evaporator 11 to the oil concentrator 26 Since the movement of the lubricating oil tank 25 is substantially the same as that of the compression refrigerator 1-14, the description thereof is omitted.

In the compression refrigerator 1-3 shown in FIG. 3, the lubricating oil is not collected directly from the evaporator 11 but is collected from the liquid pool part a <b> 1 of the suction part of the compressor 13. Here, the valve V ₃ ′ is opened, the refrigerant containing the lubricating oil in the liquid reservoir a 1 is introduced into the oil concentrator 26, the valve V ₃ ′ is closed after the movement is completed, the valve V ₈ is opened, and the oil concentrator 26 The solution (refrigerant liquid containing lubricating oil) is heated to concentrate the lubricating oil. After the concentration is completed, the vaporized refrigerant vapor is accumulated in the oil concentrator 26 by closing the valve V ₃ ′ and the valve V ₈ , so that the internal pressure of the oil concentrator 26 increases. When the predetermined pressure or temperature is reached, the valve V ₁₁ provided in the pipe 28 connecting the oil concentrator 26 and the lubricating oil tank 25 is opened, so that the lubricating oil concentrated solution becomes the lubricating oil by the pressure in the oil concentrator 26. Move into the tank 25. Thus, by utilizing the increased internal pressure by heating, since the solution can also be moved to the lubricating oil tank 25 may be omitted piping 49 and the valve V _8.

The compression refrigerator 1-5 shown in FIG. 5 integrates the lubricating oil tank 25 with the gear box 32 as described above. Here, the valve V ₁₀ ′ is opened, the refrigerant containing the lubricating oil in the liquid reservoir a1 of the suction portion of the compressor 13 is introduced into the oil concentrator 26, the valve V ₁₀ ′ is closed after the movement is completed, and the valve V ₈ The refrigerant containing the lubricating oil in the oil concentrator 26 is heated to concentrate the lubricating oil. After the concentration is completed, the vaporized refrigerant vapor is accumulated in the oil concentrator 26 by closing the valve V ₁₀ ′ and the valve V ₈ , so that the internal pressure of the oil concentrator 26 increases. When the predetermined pressure or temperature is reached, the valve V ₁₁ provided in the pipe 28 connecting the oil concentrator 26 and the lubricating oil tank 25 is opened, so that the lubricating oil concentrated solution becomes the lubricating oil by the pressure in the oil concentrator 26. Move into the tank 25. Thus, by utilizing the increased internal pressure by heating, since the solution can also be moved to the lubricating oil tank 25 may be omitted piping 49 and the valve V _8.

As described above, the compression type refrigerator 1-6 of FIG. 6 has the compressor 13 of the compression type refrigerator 1-5 shown in FIG. 5 as a single stage, and does not have an economizer 18 and is provided with a gas phase in the lubricating oil tank 25. The part is connected to the vapor phase part of the evaporator 11 via the gear box 32 and the pipe 63, and the pressure equalization destination of the lubricating oil tank 25 is the evaporator 11. Here, the valve V ₁₀ ′ is opened, the refrigerant containing the lubricating oil in the liquid reservoir a1 of the suction portion of the compressor 13 is introduced into the oil concentrator 26, the valve V ₁₀ ′ is closed after the movement is completed, the valve V ₈ is opened, The refrigerant containing the lubricating oil in the oil concentrator 26 is heated to concentrate the lubricating oil. After the concentration is completed, the vaporized refrigerant vapor is accumulated in the oil concentrator 26 by closing the valve V ₁₀ ′ and the valve V ₈ , so that the internal pressure of the oil concentrator 26 increases. When a predetermined pressure or temperature is reached, the valve V ₁₁ provided in the pipe 28 connecting the oil concentrator 26 and the lubricating oil tank 25 is opened to increase the lubricating oil concentration due to the pressure in the oil concentrator 26. The lubricating oil concentrated solution moves into the lubricating oil tank 25. Also in FIG. 6, using the elevated pressure by heating, since the solution can also be moved to the lubricating oil tank 25 may be omitted piping 49 and the valve V _8.

As described above, the compression refrigerator 1-7 shown in FIG. 7 is a compression refrigerator having a refrigeration cycle duplicated by two closed systems in which a refrigerant is sealed. The specific oil concentration recovery process is as follows: the valve V ₁₁ , the valve V ₈ are closed, the valve V ₂₀ is opened, the valve V ₉ is further opened, and the oil concentrator 26 contains the lubricating oil of the low-pressure evaporator 11-1. was introduced, the liquid level sensor 41 detects a predetermined high liquid level closes the valve V _9. Then open the valve V _3-1 a predetermined period of time, to introduce the liquid in the liquid reservoir a1-1 suction of the low pressure compressor 13-1 of the low pressure refrigeration cycle side to the oil condenser 26, further valves V _{3- 2} is opened for a predetermined time, and the liquid in the liquid reservoir a1-2 of the high-pressure compressor 13-2 on the high-pressure refrigeration cycle side is also introduced into the oil concentrator 26. When the valve V _3-1 and the valve V _3-2 are closed and the valve V ₂₀ is opened, the refrigerant evaporates by heating the solution in the oil concentrator 26 and the lubricating oil is concentrated. The evaporated refrigerant vapor is expelled to the suction of the low pressure compressor 13-1 through the pipe 46 and valve V _20.

Detecting the completion concentrated by detecting a predetermined low liquid level in the liquid level sensor 41 closes the valve V _20. Several minutes later, the internal pressure of the oil concentrator 26 increases. When the internal pressure of the oil concentrator 26 reaches a predetermined pressure or when the solution reaches a predetermined temperature, or when a predetermined time elapses, the valve V ₁₁ is opened to send the lubricating oil concentrated solution in the oil concentrator 26 to the lubricating oil tank 25. Close the valve V ₁₁ after a predetermined time to complete the movement of the lubricating oil. The completion of the movement of the lubricating oil may be detected not by time management but by detecting a predetermined lower liquid level of the oil concentrator 26 by the liquid level sensor 41. Such a concentration and recovery process of the lubricating oil is repeated during operation of the present compression type refrigerator 1-7. Also in FIG. 7, by utilizing the increased internal pressure by heating, since the solution can also be moved to the lubricating oil tank 25 may be omitted piping 49 and the valve V _8.

As described above, the compression refrigerator 1-8 shown in FIG. 8 is a compression refrigerator having a refrigeration cycle that is duplicated by two closed systems filled with refrigerant. Lubricating oil recovery from the evaporation system is performed only from the liquid reservoir a1-1 of the suction portion of the low-pressure compressor 13-1 and the liquid reservoir a1-2 of the suction portion of the high-pressure compressor 13-2, that is, the liquid reservoir. between a1-1 oil concentrator 26 connected by a pipe 45-1 having a valve V _3-1, between the liquid reservoir portion a1-2 oil concentrator 26 with a valve V _3-2 piping Connected at 45-2. Further, the refrigerant from the low-pressure condenser 17-1 is supplied to the electric motor 15 through the pipe 36a by the pump 35, and the refrigerant which is cooled by the electric motor 15 is returned to the low-pressure condenser 17-1 through the pipe 36b. The gas phase portion of the lubricating oil tank 25 is connected to the gas phase portion of the low pressure economizer 18-1 of the low pressure refrigeration cycle system by the pressure equalizing pipe 31, and the pressure equalizing destination of the lubricating oil tank 25 is the low pressure economizer 18-1. Connected by a pipe 67 having an upstream side and a high pressure evaporator 11-2 and a valve V ₁₆ of the expansion valve 19b-1 of the low-pressure evaporator 11-1, the low-pressure evaporator 11-1 and the high-pressure evaporator 11-2 The liquid level is adjusted to be approximately the same.

A specific oil concentration recovery process will be described below. Close the valves V _3-1 and V _3-2 . Open the valve V _8, then open the valve V _3-1 the predetermined time, to move the refrigerant (including lubricating oil) at the suction portion of the liquid reservoir portion a1-1 of the low pressure compressor 13-1 to the oil concentrator 26 Close valve V _3-1 . Thereafter, the valve V _3-2 is opened for a predetermined time, and the refrigerant (including lubricating oil) in the liquid reservoir a1-2 of the suction part of the high-pressure compressor 13-2 is moved to the oil concentrator 26, and the valve V _3-2 Close. In this state, by heating the solution in the oil concentrator 26 (solution in which the lubricating oil and the refrigerant liquid are mixed), the refrigerant evaporates and the lubricating oil is concentrated to become a lubricating oil concentrated solution. Evaporated refrigerant by opening the valve V _14, passes through the refrigerant pipe 21-1a, it is guided to the suction portion of the low pressure compressor 13-1. After the elapse of a predetermined time, the valves V ₁₄ and V ₈ are closed as the completion of concentration, and the process moves to the step of moving the lubricating oil concentrated solution from the oil concentrator 26 to the lubricating oil tank 25. The movement of the lubricating oil concentrate solution is than performed by utilizing the internal pressure rise of the oil concentrator 26, opening the valve V _11, moves the lubricating oil concentrate solution in the oil concentrator 26 to the lubricating oil tank 25, close the valve V ₁₁ as movement completion after a predetermined time, opening a valve V _8. These steps are repeated. Also in FIG. 8, by utilizing the increased internal pressure by heating, since the solution can also be moved to the lubricating oil tank 25 may be omitted piping 49 and the valve V _8.

In the compression type refrigerators of the sixth to eighth reference examples , the refrigerant liquid is moved from the location (A) where the lubricating oil to be collected exists to the oil concentrator 26 (depending on the position head, even if there is a pressure difference) Good) and heat concentrate in oil concentrator 26. The refrigerant vapor evaporated by the oil concentrator 26 is guided to the evaporator system (the evaporator 11 or the suction portion of the compressor 13). When the concentration of the lubricating oil is completed, the connection between the oil concentrator 26 and other equipment is cut off and heating is continued to increase the pressure, and the valve V ₁₁ provided in the pipe 28 connecting the oil concentrator 26 and the lubricating oil tank 25 is provided. , And the concentrated lubricating oil concentrated solution in the oil concentrator 26 is moved to the oil concentrator 26. The above (A) is as follows.

  (A): The place (apparatus) where the refrigerant liquid mixed with the lubricating oil to be collected exists is the liquid reservoir a1 of the suction section of the evaporator 11 and the compressor 13. (However, when the gas-liquid separation is sufficiently performed in the evaporator 11 and the refrigerant mist does not fly from the evaporator 11 to the compressor 13, lubricating oil is mixed in the liquid reservoir a <b> 1 of the suction portion of the compressor 13. The refrigerant does not accumulate.) The pressure equalization destination of the lubricating oil tank 25 may be anywhere such as the evaporation system (the evaporator 11 or the suction portion of the compressor 13), the economizer 18 or the condenser 17. However, the type of heat source is limited in order to obtain a pressure higher than the pressure at the pressure equalization destination.

The types of valves that are turned ON / OFF to recover the lubricating oil are as follows. The place (A) where the refrigerant liquid containing the lubricating oil to be recovered exists, that is, the valve V ₉ provided in the pipe 48 connecting the evaporator 11 and the oil concentrator 26, and the liquid pool in the suction portion of the compressor 13 Valve V ₃ , V ₁₀ ′ provided in the pipe 45 connecting the part a1 and the oil concentrator 26, valve V ₃ ′ provided in the pipe 45 leading the refrigerant vapor evaporated in the oil concentrator 26 to the evaporation system, valve V ₁₀ , V ₁₄ , V ₂₀ , a valve V ₁₁ provided in a pipe 28 connecting the oil concentrator 26 and the lubricating oil tank 25, and the like. These valves are not necessarily to all needs, for example, by also serves as a valve V ₉ and the valve V ₁₀ in FIG. 1, or may be subjected to a valve V ₁₁ in the check valve V ₁₃ (see FIG. 2).

The following are typical examples of valves that are turned ON / OFF in the lubricant recovery process.
(1) With the movement of the solution from the oil concentrator 26 to the lubricating oil tank 25 stopped (valve V ₁₁ : closed), the oil concentrator 26 is equalized to the pressure level of the evaporator 11 (valves V ₁₀ , V ₁₄ , V ₂₀ : open), and the oil concentrator 26 is lubricated by communicating between the suction portion of the evaporator 11 or the compressor 13 and the oil concentrator 26 (valve V ₉ : open, valve V ₃ : open). Introduce refrigerant containing oil.
(2) Stop the introduction of the solution into the oil concentrator 26 (valve V ₉ : closed, valve V ₃ : closed) and other valves maintain the state of (1) (valves V ₁₀ , V ₁₄ , V ₂₀ : open) , Valve V ₁₁ : closed), the refrigerant in the oil concentrator 26 is evaporated, and the lubricating oil is concentrated. (If mist accumulated in the suction portion of the liquid reservoir portion a1 of the compressor 13 is small, it may be left valve V ₃ is opened.)

(3) After completing the concentration of the lubricating oil, shut off the pipes that lead the refrigerant vapor evaporated from the oil concentrator 26 to the evaporator pressure level to the suction part of the compressor 13 (valves V ₁₀ , V ₁₄ , V ₂₀ : closed). By heating, the pressure in the oil concentrator 26 gradually increases. (Note that (if the valve V ₉ is opened in 2), (3) in closed together with the valve _{V 10, V 14, V 20} .)
The timing of opening the (4) valve V _11, the detection of the oil concentrator 26 pressure, or temperature sensing of the solution, or the valve V _10, V _14, V ₂₀ may be time after engaging (valve V ₁₁ is provided pipe A check valve may be added to the valve 28 to prevent backflow even if the timing is shifted. Alternatively, the check valve may be used in place of the valve V ₁₁ to move the solution as the internal pressure of the oil concentrator 26 increases. You may do it.)
(5) The solution movement in the oil concentrator 26 is completed (valve V ₁₁ : closed), and the valves V ₁₀ , V ₁₄ , and V ₂₀ are opened and the process returns to (1). A summary of the above is shown in FIG.

  By bringing the oil concentrator 26 to the evaporator pressure level and heating the solution (mixed solution of refrigerant and lubricating oil) in the oil concentrator 26, the refrigerant evaporates and the lubricating oil concentration increases. As the heat source used for this heating, various heat sources can be applied in the same manner as (a) to (f) shown in the first to seventh embodiments.

When the pressure equalization destination of the lubricating oil tank 25 is the evaporator 11, all of (a) to (e) can be used.
When the pressure equalization tip of the lubricating oil tank 25 is the economizer 18, it can be used except for (c) ((f) cannot be used depending on the temperature).
When the pressure equalizing point of the lubricating oil tank 25 is the condenser 17, (d) or (e) can be used.
When the refrigerant liquid is transferred from the evaporator 11 to the oil concentrator 26, when the heating source is the electric heater 24, it is preferable to stop the heater heating.

  The concentration of the lubricating oil in the oil concentrator 26 in which the gas phase portion is connected to the low pressure side (the evaporator 11 or the suction portion of the compressor 13) by piping is, for example, the refrigerant dew point (or vapor pressure), the lubricating oil and the refrigerant It can be calculated from the relationship with the temperature of the mixed solution. Usually, since the temperature of the evaporator 11 is substantially constant, it is necessary to consider the case where the solution temperature has not been lowered. For example, the concentration is not judged for several minutes after activation. Further, the concentration magnification can be known by the liquid level sensor of the oil concentrator 26. It is also possible to manage the movement amount of the refrigerant containing the lubricating oil from the evaporator 11 with a high liquid level sensor, and manage the completion of concentration (reaching the concentration ratio) at the middle liquid level (or low liquid level). Even if the concentration is not accurately detected, the rough concentration management can be performed in the time of exposure to the low pressure state.

The solution (including the refrigerant in the lubricating oil) moves from the oil concentrator 26 to the lubricating oil tank 25 using the pressure difference between the oil concentrator 26 that is the moving source and the lubricating oil tank 25 that is the moving destination. be able to. The lower liquid level of the oil concentrator 26 may be detected by a liquid level sensor to detect the movement completion, or the movement completion may be estimated from the elapsed time from the start of movement. In addition, when managing by elapsed time, you may prevent a blow-through using a float valve etc. When the valve V ₁₁ is opened without detecting the pressure, a check valve may be provided to prevent backflow from the lubricating oil tank 25.

  The embodiments of the present invention have been described above. However, 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. Can be modified. Note that any shape or structure not directly described in the specification and drawings is within the technical scope of the present invention as long as the effects of the present invention are achieved.

It is a figure which shows the whole schematic structural example of the compression type refrigerator 1-1 which concerns on a reference example . It is a figure which shows the example of whole schematic structure of the compression type refrigerator 1-2 which concerns on a reference example . It is a figure which shows the example of whole schematic structure of the compression type refrigerator 1-3 which concerns on a reference example . It is a figure which shows the example of whole schematic structure of the compression type refrigerator 1-4 which concerns on a reference example . It is a figure which shows the example of a whole schematic structure of the compression type refrigerator 1-5 which concerns on a reference example . It is a figure which shows the example of a whole schematic structure of the compression type refrigerator 1-6 which concerns on a reference example . It is a figure which shows the example of whole schematic structure of the compression type refrigerator 1-7 which concerns on this invention. It is a figure which shows the example of whole schematic structure of the compression type refrigerator 1-8 which concerns on this invention. It is a figure which shows the whole schematic structural example of the compression refrigerator 1-9 which concerns on a reference example . It is a figure which shows the example of a whole schematic structure of the compression type refrigerator 1-10 which concerns on a reference example . It is a figure which shows the example of a whole schematic structure of the compression type refrigerator 1-11 which concerns on a reference example . It is a figure which shows the whole schematic structural example of the compression refrigerator 1-12 which concerns on a reference example . It is a figure which shows the example of a whole schematic structure of the compression type refrigerator 1-13 which concerns on a reference example . It is a figure which shows the example of a whole schematic structure of the compression type refrigerator 1-14 which concerns on a reference example . It is a figure which shows the whole schematic structural example of the compression refrigerator 1-15 which concerns on a reference example . It is a figure which shows the detail of a compressor, an electric motor, and a bearing part. It is a figure which shows an example of the relationship between a mixed solution, a refrigerant | coolant dew point, and a refrigerant | coolant density | concentration. It is a figure which shows the basic example of a combination of lubricating oil collection related apparatuses. It is a figure which shows the basic example of a combination of lubricating oil collection related apparatuses. It is a figure which shows the operation example of the valve in lubricating oil collection | recovery. It is a figure which shows the operation example of the valve in lubricating oil collection | recovery.

Explanation of symbols

1-1-15 Compression refrigerator 11 Evaporator 11-1 Low pressure evaporator 11-2 High pressure evaporator 13 Compressor 13-1 Low pressure compressor 13-2 High pressure compressor 13a Impeller 15 Electric motor 15a Rotor 15b Rotor chamber 17 Condenser 17-1 Low pressure condenser 17-2 High pressure condenser 18 Economizer 18-1 Low pressure economizer 18-2 High pressure economizer 19, 19a, b, 19b-1, 2 Expander (expansion valve)
21a-d, 21-1a-d, 21-2a-d Refrigerant piping 22 Booster 23 Bearing 24 Electric heater 25 Lubricating oil tank 26 Oil concentrator 27 Oil pump 28 Piping 29a Lubricating oil supply piping 29b Lubricating oil return piping 31 Pressure equalizing pipe 32 Gear box 33 Oil cooler (heat exchanger)
34a, b piping 35 pump 36a, b, c piping 41 liquid level sensor 42 temperature sensor 44 check valve 45 piping 46 piping 48 piping 49 piping 55 transfer tank 56 piping 57 piping 60 heating means 61 heater 62 piping 63 piping 64 ejector 65 Piping 66 Piping 67 Piping 68 Pressure equalizing pipe 70 Bearing chamber 71 Pressure equalizing pipe V ₁ valve V ₂ valve V ₃ valve V _3-1 valve V _3-2 valve V ₃ 'Three-way valve V ₄ Three-way valve V ₆ valve V ₇ valve V ₈ valve V ₉ valve V ₁₀ valve V ₁₀ 'valve V ₁₁ valve V ₁₁ ' valve V ₁₃ 'check valve V ₁₆ valve V ₂₀ valve

Claims (8)

A refrigeration cycle system that connects a compressor, a condenser, and an evaporator with refrigerant piping through which a refrigerant circulates is provided with two systems, a high-pressure side and a low-pressure side, and the compressors of both refrigeration cycle systems are driven by a single electric motor. And cooling the electric motor with a refrigerant of a high-pressure side refrigeration cycle system,
A lubricating oil tank that stores lubricating oil for lubricating the bearing of the compressor; and the lubricating oil in the lubricating oil tank is supplied to the bearing by a single oil circulation pump and the lubricating oil is lubricated. 1 system of lubricating oil circulation system to return to the lubricating oil tank,
Furthermore, by connecting the evaporator of the low-pressure side refrigeration cycle system and the evaporator of the high-pressure side refrigeration cycle system by piping, and providing an on-off valve in the piping to adjust the liquid level of both evaporators to substantially the same level, Return the refrigerant that has moved to the refrigeration cycle system on the high pressure side to the refrigeration cycle system on the low pressure side,
The gas phase part in the lubricating oil tank and the gas phase part of the low pressure equipment of the high pressure side refrigeration cycle system are connected by a pressure equalizing pipe,
An oil concentrator for concentrating the lubricating oil connected to the low-pressure side refrigeration cycle evaporator and a pipe with a switching valve is provided,
The lubricating oil tank and the oil concentrator are connected by a liquid return pipe, and an opening / closing valve is provided in the liquid return pipe,
A compression-type refrigerator having a gas phase portion of the oil concentrator connected to an evaporator or a suction portion of the low-pressure side refrigeration cycle system by piping, and an open / close valve provided on the piping. A refrigeration cycle system that connects a compressor, a condenser, and an evaporator with refrigerant piping through which a refrigerant circulates is provided with two systems, a high-pressure side and a low-pressure side, and the compressors of both refrigeration cycle systems are driven by a single electric motor. And cooling the electric motor with a refrigerant of a high-pressure side refrigeration cycle system,
A lubricating oil tank that stores lubricating oil for lubricating the bearing of the compressor; and the lubricating oil in the lubricating oil tank is supplied to the bearing by a single oil circulation pump and the lubricating oil is lubricated. 1 system of lubricating oil circulation system to return to the lubricating oil tank,
Furthermore, by connecting the evaporator of the low-pressure side refrigeration cycle system and the evaporator of the high-pressure side refrigeration cycle system by piping, and providing an on-off valve in the piping to adjust the liquid level of both evaporators to substantially the same level, Return the refrigerant that has moved to the refrigeration cycle system on the high pressure side to the refrigeration cycle system on the low pressure side,
The gas phase part in the lubricating oil tank and the gas phase part of the low pressure equipment of the high pressure side refrigeration cycle system are connected by a pressure equalizing pipe,
An oil concentrator for concentrating the lubricating oil connected to the low-pressure side refrigeration cycle evaporator and a pipe with a switching valve is provided,
The lubricating oil tank and the oil concentrator are connected by a liquid return pipe, and an opening / closing valve is provided in the liquid return pipe,
The gas phase part of the oil concentrator is connected to the evaporator of the low-pressure side refrigeration cycle system or the suction part of the compressor by a pipe, and an open / close valve is provided in the pipe,
Compressive refrigeration characterized in that the oil concentrator and a device having a pressure higher than the pressure of the device connected by piping to the gas phase portion of the lubricating oil tank are connected by piping, and an open / close valve is provided in the piping. Machine. The compression refrigerator according to claim 1 or 2 ,
The oil concentrator is provided with concentration detecting means for detecting the concentration of oil, and control means for moving the liquid of the oil concentrator to the lubricating oil tank when the completion of oil concentration is detected by the output of the concentration detecting means. A compression type refrigerator characterized by the above. In the compression refrigerator according to claim 3 ,
The concentration detecting means is a temperature sensor that detects a dew point of the solution and a temperature of the solution, or a vapor pressure sensor that detects a vapor pressure of the oil concentrator and a temperature sensor that detects the temperature of the solution. Type refrigerator. The compression refrigerator according to claim 1 or 2 ,
A compression type refrigeration machine characterized in that at least one of taking in and out of the liquid from the oil concentrator is performed by detecting the liquid level of the oil concentrator. The compression refrigerator according to claim 1 or 2 ,
A compression type refrigerator that performs at least one of taking in and out of the liquid from the oil concentrator based on an elapsed time of the taking in and out. The operation method of the compression type refrigerator which transfers the lubricating oil concentration solution in the oil concentrator in the compression type refrigerator according to claim 1 to the lubricating oil tank,
After the completion of the concentration of the lubricating oil by heating the refrigerant containing the lubricating oil in the oil concentrator, the lubricating oil concentrated solution is reduced by the pressure in the oil concentrator increased by the refrigerant vapor evaporated and accumulated in the oil concentrator. A method for operating a compression refrigerator, wherein the method is transferred to a lubricating oil tank. The operation method of the compression type refrigerator which transfers the lubricating oil concentration solution in the oil concentrator in the compression type refrigerator according to claim 2 to the lubricating oil tank,
After the completion of the concentration of the lubricating oil by heating the refrigerant containing the lubricating oil in the oil concentrator, the pressure of the equipment higher than the pressure of the equipment in which the gas phase part of the lubricating oil tank is connected by piping is introduced, and the pressure A method of operating a compression refrigerator, wherein the lubricating oil concentrated solution is transferred to the lubricating oil tank.

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