Refrigerant charging method

Abstract

This refrigerant charge method is for a refrigeration circuit provided with a compressor, a condenser, a throttle device, an evaporator, and a first port which is disposed at a high-pressure part of the compressor or at a position downstream of the compressor and upstream of the throttle device, and the method comprises: connecting, to the first port, the mouth of a container having sealed therein refrigerants which include a high-boiling point refrigerant in a liquid state and a middle-boiling point refrigerant which is in a wet gaseous state and has a boiling point lower than the high-boiling point refrigerant; and charging the refrigeration circuit with at least a portion of the refrigerants in the container, through the first port from the container with the mouth oriented downward.

Description

[Technical field]

[0001] The present invention relates to a refrigerant charging method. [Background technology]

[0002] Patent Document 1 discloses a method for charging a refrigerant circuit with a non-azeotropic refrigerant mixture using a cylinder that contains a chargeable amount of the non-azeotropic refrigerant mixture at one time. In this method, the refrigerant circuit is applied to an air conditioner, and R407C is used as the non-azeotropic refrigerant mixture.

[0003] R407C is composed of HFC32 (boiling point: -51.7°C), HFC125 (boiling point: -48.5°C), and HFC134a (boiling point: -26.5°C). The boiling points of these three refrigerants are relatively close to each other. Therefore, it is considered that these three refrigerants are mixed relatively evenly in the cylinder at room temperature before being charged into the refrigerant circuit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 08-200897 Summary of the Invention [Problem to be solved by the invention]

[0005] For example, some non-azeotropic refrigerants are composed of multiple refrigerants with significantly different boiling points, such as the non-azeotropic refrigerant filled in the refrigeration circuit of an ultra-low temperature freezer that realizes extremely low temperatures of -80°C or less. These multiple refrigerants may exist separately from each other in the container in which they are sealed before being filled into the refrigeration circuit. A method is required to reliably fill the refrigeration circuit with a non-azeotropic refrigerant in such a state.

[0006] An object of the present disclosure is to provide a refrigerant charging method capable of reliably charging a non-azeotropic refrigerant mixture into a refrigeration circuit. [Means for solving the problem]

[0007] The refrigerant charging method according to the present disclosure includes: A method for charging a refrigerant into a refrigeration circuit including a compressor, a condenser, a throttling device, an evaporator, and a first port disposed in a high-pressure portion of the compressor or downstream of the compressor and upstream of the throttling device, comprising: a container containing a refrigerant including a high-boiling-point refrigerant in a liquid state and a medium-boiling-point refrigerant in a wet gas state having a boiling point lower than that of the high-boiling-point refrigerant, the container having an opening connected to the first port; The method includes charging at least a portion of the refrigerant in the container through a first port from the container in a downward orientation to a refrigeration circuit. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a refrigerant charging method that can reliably charge a non-azeotropic refrigerant mixture into a refrigeration circuit. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an example of a refrigeration circuit. [Diagram 2] FIG. 2 is a schematic diagram showing a vessel and the refrigerant therein. [Diagram 3] FIG. 3 is a schematic diagram showing a vessel and the refrigerant therein. [Figure 4] FIG. 4 is a schematic diagram of the jig. [Diagram 5] FIG. 5 is a schematic diagram showing a container and the refrigerant and oil carrier agent therein. [Figure 6] FIG. 6 is a schematic diagram showing a modified vessel and the refrigerant therein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] 1 is a schematic diagram of a refrigeration circuit 100 according to an embodiment of the present disclosure. The refrigeration circuit 100 is applied to a refrigeration device such as an ultra-low temperature freezer.

[0011] The refrigeration circuit 100 includes a compressor 1, a condenser 2, a gas-liquid separator 3, a first heat exchanger 4, an auxiliary throttling device 5, a throttling device 6, a second heat exchanger 7, and an evaporator 8. The refrigeration circuit 100 may also include a refrigerant tank 9 and a throttling device 10 for connecting to the refrigerant tank.

[0012] In Fig. 1, the lines connecting the above elements constituting the refrigeration circuit 100 indicate piping, and the arrows in Fig. 1 indicate the flow of the refrigerant in the piping. The refrigerant flowing through the refrigeration circuit 100 is a non-azeotropic refrigerant mixture, which is a mixture of refrigerants with different boiling points. The non-azeotropic refrigerant mixture includes a high boiling point refrigerant, a mid-boiling point refrigerant with a boiling point lower than that of the high boiling point refrigerant, and a low boiling point refrigerant with a boiling point lower than that of the mid-boiling point refrigerant. Hereinafter, the non-azeotropic refrigerant mixture may be simply referred to as a refrigerant.

[0013] Compressor 1 compresses the sucked refrigerant and discharges it into a pipe. The discharged refrigerant passes through the pipe and flows into condenser 2. Compressor 1 has a low-pressure portion (where the refrigerant exists before being compressed) between an inlet port that sucks in the refrigerant and a portion that compresses the refrigerant (e.g., a cylinder), and a high-pressure portion (where the refrigerant exists after being compressed) between the portion that compresses the refrigerant and a discharge port that discharges the refrigerant.

[0014] The condenser 2 is a heat exchanger equipped with a fan rotated by a fan motor. The condenser 2 is a heat exchanger that cools the refrigerant by heat exchange with the surrounding air sent in by the fan, and condenses at least a part of the refrigerant. The refrigerant that passes through the condenser 2 flows into the gas-liquid separator 3.

[0015] The gas-liquid separator 3 is a container that separates the refrigerant into gas and liquid. The refrigerant in a gaseous state, i.e., components that are not condensed in the condenser 2 (components with a relatively low boiling point), flows out of the gaseous state from the gas-liquid separator 3 and flows into the inner tube 4a of the first heat exchanger 4. The refrigerant in a liquid state, i.e., components that are condensed in the condenser 2 (components with a relatively high boiling point), flows out of the gas-liquid separator 3 and flows into the auxiliary throttling device 5.

[0016] The auxiliary throttling device 5 is, for example, a capillary tube. When passing through the auxiliary throttling device 5, the refrigerant is throttled and expands, and the pressure and temperature of the refrigerant decrease. The refrigerant that flows out of the auxiliary throttling device 5 flows into the outer tube 4b of the first heat exchanger 4.

[0017] The first heat exchanger 4 is a heat exchanger including an inner tube 4a and an outer tube 4b surrounding the inner tube 4a. The refrigerant flowing through the inner tube 4a exchanges heat with the refrigerant flowing through the outer tube 4b, and loses heat.

[0018] The refrigerant flowing out from the inner tube 4a of the first heat exchanger 4 flows into the expansion device 6. The expansion device 6 is, for example, a capillary tube. When passing through the expansion device 6, the refrigerant is throttled and expands, and the pressure and temperature of the refrigerant decrease.

[0019] The expansion device 6 and the outer tube 7b of the second heat exchanger 7 constitute the second heat exchanger 7. The expansion device 6 is surrounded by the outer tube 7b. Therefore, the refrigerant passing through the expansion device 6 exchanges heat with the refrigerant passing through the outer tube 7b, losing heat and becoming even lower in temperature.

[0020] In the process of passing through the inner tube 4a of the first heat exchanger 4 and the expansion device 6, the refrigerant passing therethrough is condensed.

[0021] The refrigerant flowing out from the expansion device 6 flows into the evaporator 8 and evaporates. At this time, the surroundings of the evaporator 8, that is, the object to be cooled, are cooled.

[0022] The refrigerant flowing out from the evaporator 8 flows into the outer pipe 7b of the second heat exchanger 7, absorbs heat from the refrigerant flowing through the expansion device 6, and flows out from the outer pipe 7b.

[0023] The refrigerant flowing out from the outer tube 7b flows into the outer tube 4b of the first heat exchanger 4, where it joins and mixes with the refrigerant flowing out from the auxiliary throttling device 5. The mixed refrigerant absorbs heat from the refrigerant flowing in the inner tube 4a of the first heat exchanger 4, evaporates completely, and flows out from the outer tube 4b.

[0024] The refrigerant flowing out from the outer pipe 4b is sucked into the compressor 1, compressed again, and discharged.

[0025] A refrigerant tank 9 may be connected to the piping located downstream of the outer pipe 4b and upstream of the compressor 1 via a throttle device 10 for connecting to the refrigerant tank.

[0026] The refrigeration circuit 100 configured as described above is divided into a high-pressure circuit in which high-pressure refrigerant exists and a low-pressure circuit in which low-pressure refrigerant exists, with the compressor 1 and the throttling device 6 as the boundaries. In FIG. 1, the parts that make up the high-pressure circuit are indicated by bold lines. The high-pressure circuit includes the high-pressure part of the compressor 1 and a part located downstream of the compressor 1 and upstream of the throttling device 6. The high-pressure circuit also includes a part between the gas-liquid separator 3 and the auxiliary throttling device 5. The low-pressure circuit also includes the low-pressure part of the compressor 1 and a part located upstream of the compressor 1 and downstream of the throttling device 6. The low-pressure circuit also includes a refrigerant tank 9 and a throttling device 10 for connecting to the refrigerant tank.

[0027] A first port 11 is disposed in the high pressure circuit. A second port 12 is disposed in the low pressure circuit. The first port 11 is provided in a pipe located downstream of the condenser 2 and upstream of the gas-liquid separator 3, as shown in FIG. 1, for example. The second port 12 is provided in a low pressure portion of the compressor 1 and a refrigerant tank 9, as shown in FIG. 1, for example. These ports are normally closed, and are connected to a refrigerant supply source when refrigerant is charged into the refrigeration circuit 100 for the first time or when refrigerant is charged for replenishment. Then, refrigerant is charged from the refrigerant supply source to the refrigeration circuit 100 through these ports. It goes without saying that the number of the first ports 11 and the second ports 12 is not limited to that shown in the figure.

[0028] FIG. 2 is a schematic cross-sectional view of a container 20 filled with a refrigerant, which is a refrigerant supply source. The container 20 includes a container body 21 and a mouth 22. The container body 21 has a cylindrical side wall, a bottom and a ceiling portion that close both ends of the side wall. The mouth 22 is provided on the ceiling portion. The container 20 is, for example, a cylinder. The container 20 does not include a siphon tube. Therefore, the container 20 can be easily manufactured. The container 20 may include a short siphon tube that does not reach the bottom of the container 20. In this case, a side hole may be formed near the base (ceiling side end) of the siphon tube. By forming the side hole, when the container 20 is placed in a position in which the mouth 20 faces downward, as will be described later, the liquid high-boiling point refrigerant 23 can be discharged from the container 20 through the siphon tube.

[0029] The container 20 has a shape that allows it to be stably placed on a horizontal surface with the bottom of the container body 21 facing down and the ceiling, i.e., the mouth 22, facing up. In other words, the container 20 can stand up on a horizontal surface. Fig. 2 shows the container 20 in a position where the mouth 22 faces upward (i.e., an upright position). Note that the container 20 may have any shape as long as it has the mouth 22.

[0030] The container 20 is filled with a non-azeotropic refrigerant mixture including a high boiling point refrigerant 23, a medium boiling point refrigerant 24 having a boiling point lower than that of the high boiling point refrigerant 23, and a low boiling point refrigerant 25 having a boiling point lower than that of the medium boiling point refrigerant.

[0031] When the container 20 is left stationary in a room temperature environment, the high boiling point refrigerant 23 is in a liquid state, the medium boiling point refrigerant 24 is in a wet gas state, and the low boiling point refrigerant 25 is in a gas state inside the container 20. Therefore, the three refrigerants exist in the container 20 in a substantially separate state.

[0032] When the container 20 is in an upright position, the high boiling point refrigerant 23 in liquid state is present near the bottom of the container body 21, the low boiling point refrigerant 25 in gas state is present near the mouth 22, and the medium boiling point refrigerant 24 in humid gas state is present between the high boiling point refrigerant 23 and the low boiling point refrigerant 25.

[0033] Furthermore, when container 20 is upside down, i.e., with opening 22 facing downwards, as shown in Figure 3, high boiling point refrigerant 23 in liquid state is present near opening 22, low boiling point refrigerant 25 in gas state is present near the bottom of container body 21, and medium boiling point refrigerant 24 in humid gas state is present between the high boiling point refrigerant 23 and the low boiling point refrigerant 25.

[0034] The high boiling point refrigerant 23, the medium boiling point refrigerant 24, and the low boiling point refrigerant 25 may be any refrigerant that is in a liquid state, a wet gas state, and a gas state, respectively, inside the container 20 placed in a normal temperature environment. For example, the high boiling point refrigerant 23 is normal butane, the medium boiling point refrigerant 24 is ethane, and the low boiling point refrigerant 25 is methane. The high boiling point refrigerant 23 may be normal butane or isobutane, the medium boiling point refrigerant 24 may be ethane, ethylene, or xenon, and the low boiling point refrigerant 25 may be methane or krypton.

[0035] When the non-azeotropic refrigerant mixture is composed of a combination of hydrocarbons, the total weight of the non-azeotropic refrigerant mixture may be 150 g or less. By keeping the total weight at 150 g or less, it is possible to comply with the IEC (International Electrotechnical Commission) standard. In addition, the hydrocarbon gas and the rare gas can suppress the environmental load.

[0036] The ratio of each refrigerant enclosed in container 20 is, for example, 50% by weight or more and 80% by weight or less of high boiling point refrigerant 23, 10% by weight or more and less than 50% by weight of medium boiling point refrigerant 24, and 20% by weight or less of low boiling point refrigerant 25, with the total of the contents of container 20 (i.e., non-azeotropic mixed refrigerant) being 100% by weight. In other words, the total of medium boiling point refrigerant 24 and low boiling point refrigerant 25 is 50% by mass or less. All the low boiling point refrigerant may be replaced with a medium boiling point refrigerant.

[0037] Charging of the refrigerant from the container 20, which is a refrigerant supply source, into the refrigeration circuit 100 is performed as follows. The refrigerant is charged before the refrigeration circuit 100 starts operating, or when a refrigerant leak occurs after the refrigeration circuit 100 starts operating. For example, charging of the refrigerant is performed when a state in which lubricating oil for lubricating the compressor 1 is likely to accumulate in the evaporator 8 continues for a certain period of time (for example, a power outage occurs when the temperature is low and the system is left for a while), and further when a refrigerant leak occurs.

[0038] First, the first port 11 and the mouth 22 are connected via a valve and a pipe. The container 20 may be provided with a valve attached to the mouth 22. In parallel with this, the container 20 is placed in the position shown in Fig. 3, that is, in the position where the mouth 22 faces downward.

[0039] Next, the valve is opened. Note that the inside of the refrigeration circuit 100 may be depressurized before the valve is opened. The depressurization can be performed, for example, by sucking the inside of the refrigeration circuit 100 with a vacuum pump through at least one of the first port 11 and the second port 12. When the valve is opened, the refrigerant sealed in the container 20 is charged into the refrigeration circuit 100 through the first port 11. In detail, the high boiling point refrigerant 23 present near the port 22 is charged first, then the medium boiling point refrigerant is charged, and finally the low boiling point refrigerant is charged.

[0040] The high boiling point refrigerant 23 charged first permeates the high pressure circuit. Then, the high boiling point refrigerant 23 enters the throttling device 6 and the auxiliary throttling device 5, which have a large piping resistance, and passes through them before entering the low pressure circuit. Due to the structure of the compressor 1, the refrigerant cannot flow from the high pressure portion of the compressor 1 to the low pressure portion.

[0041] The force pushing the high boiling point refrigerant 23 that has entered the throttling device 6 and the auxiliary throttling device 5, which have a large piping resistance, toward the low pressure circuit is provided by the medium boiling point refrigerant 24 and the low boiling point refrigerant 25 in the container 20. This is because the medium boiling point refrigerant 24 and the low boiling point refrigerant 25 have lower boiling points than the high boiling point refrigerant 23, and therefore have a higher pressure than the high boiling point refrigerant 23 when they are in the same temperature environment. In other words, the high boiling point refrigerant 23 that has spread through the high pressure circuit is pushed by the medium boiling point refrigerant 24 and the low boiling point refrigerant 25 in the container 20, and enters the throttling device 6 and the auxiliary throttling device 5, and can pass through the throttling device 6 and the auxiliary throttling device 5. Following the high boiling point refrigerant 23, the medium boiling point refrigerant 24 and the low boiling point refrigerant 25 can enter the high pressure circuit.

[0042] When substantially all of the high boiling point refrigerant 23 has been charged into the refrigeration circuit 100, the medium boiling point refrigerant 24 is then charged into the refrigeration circuit 100, and finally, the low boiling point refrigerant 25 is charged into the refrigeration circuit 100. As the charging of the refrigerant progresses, the pressure of the refrigerant in the refrigeration circuit 100 increases, but since the low boiling point refrigerant 25 charged last is the refrigerant that will have the highest pressure in the same temperature environment, substantially the entire amount of refrigerant in the container 20 can be charged.

[0043] However, while charging the refrigerant, the refrigerant pressure at least in the high pressure circuit portion gradually increases. Therefore, while refrigerant remains in the container 20, the refrigerant may not or may not easily enter the refrigeration circuit 100 from the first port 11. In this case, the following process may be performed.

[0044] That is, after the refrigerant in the container 20 is charged to the refrigeration circuit 100 through the first port 11, at least a part of the refrigerant remaining in the container 20 may be charged to the refrigeration circuit 100 through the second port 12. The low pressure circuit in which the second port 12 is provided is located downstream of the throttling device 6 and the auxiliary throttling device 5, which have a large pipe resistance, as viewed from the first port 11. Therefore, even if the high boiling point refrigerant 23 is charged to the high pressure circuit upstream of the throttling device 6 and the auxiliary throttling device 5, the high boiling point refrigerant 23 cannot immediately flow into the low pressure circuit. In other words, the low pressure state of the low pressure circuit continues for at least a while after the start of refrigerant charging. Therefore, even if the refrigerant remaining in the container 20 cannot enter the refrigeration circuit 100 (specifically, the high pressure circuit) from the first port 11, the low boiling point refrigerant and the intermediate boiling point refrigerant remaining in the container 20 can be fed into the refrigerant circuit (specifically, the low pressure circuit) from the second port 12.

[0045] At this time, the orientation of the container 20 may be such that the mouth 22 faces upward or downward. In either case, the entire amount remaining in the container 20 can be reliably charged to the refrigeration circuit 100.

[0046] If the refrigerant charged from the first port 11 is sufficient, the refrigeration circuit 100 does not need to be provided with the second port 12.

[0047] Moreover, the refrigerant inlet can be switched from the first port 11 to the second port 12 by disconnecting the container 20 from the first port 11, and then connecting the container 20 to the second port 12 via a pipe and a valve. Moreover, a jig 30 described below may be used.

[0048] 4 is a schematic diagram of the jig 30. The jig 30 includes a container connection port 31, a branch pipe 32, two port connection ports 33, and two valves 34. The two valves 34 form a path switching device.

[0049] The container connection port 31 is a connection part connected to the port 22 of the container 20. The branch pipe 32 is a pipe having a shape in which one pipe branches into two pipes, and the container connection port 31 is attached to the end of one pipe before the branch. In addition, a port connection port 33 is attached to each end of the two pipes after the branching of the branch pipe 32. The port connection port 33 is a connection part connected to the first port 11 or the second port 12. A valve 34 is attached to each of the two pipes after the branching of the branch pipe 32.

[0050] When such a jig 30 is used, the refrigerant is charged from the container 20 to the refrigeration circuit 100 as follows. First, the two valves 34 are closed. Then, the port 22 of the container 20 is connected to the container connection port 31, one side of the port connection port 33 is connected to the first port 11, and the other side of the port connection port 33 is connected to the second port 12. Around the same time as these connections are made, the container 20 is placed in a position in which the port 22 faces downward.

[0051] Next, the valve 34 attached to the pipe connected to the first port 11 of the two pipes branched from the branch pipe 32 is opened. Then, the refrigerant sealed in the container 20 is charged into the refrigeration circuit 100 through the first port 11. In detail, the high boiling point refrigerant 23 present near the port 22 is charged first.

[0052] After a certain amount of time has passed, the valve 34 attached to the pipe connected to the first port 11 is closed, and then the valve 34 attached to the pipe connected to the second port 12 is opened. That is, the path is switched by the path switching device. Then, the refrigerant remaining in the container 20 is charged to the refrigerant circuit from the second port 12. Note that the opening and closing of the valve 34 may be performed while measuring the weight of the container 20, and may be performed when the weight reaches a predetermined value, or may be performed when a pressure gauge attached to the refrigeration circuit 100, the jig 30, or the container 20 indicates a predetermined pressure.

[0053] By using the jig 30, the position where the refrigerant is charged from the container 20 to the refrigeration circuit 100 can be easily changed, and therefore the refrigerant in the container 20 can be reliably charged to the refrigeration circuit 100.

[0054] Also, the port 22 of the container 20 may be connected to the second port 12 instead of the first port 11, and the refrigerant may be charged into the refrigeration circuit 100 via the second port 12 from the beginning. In this case, the container 20 is placed in a position in which the port 22 faces upward (i.e., in an upright position). That is, the low boiling point refrigerant 25 present at the top of the container 20 is charged into the refrigeration circuit 100 (specifically, the low pressure circuit) first. Next, the intermediate boiling point refrigerant 24 is charged into the refrigeration circuit 100.

[0055] When the container 20 is in an upright position, the high boiling point refrigerant 23 in a liquid state is located at the bottom of the container 20 and cannot enter the refrigeration circuit 100. After the low boiling point refrigerant 25 and the medium boiling point refrigerant 24 are charged into the refrigeration circuit 100 via the second port 12, the position of the container 20 is changed to a position where the mouth 22 faces downward. Then, the high boiling point refrigerant 23 in the container 20 is charged into the refrigeration circuit 100 via the second port 12.

[0056] The low boiling point refrigerant 25 and the medium boiling point refrigerant 24 have small molecular weights and can pass through the throttling device 6 and the auxiliary throttling device 5 relatively easily. Therefore, the low boiling point refrigerant 25 and the medium boiling point refrigerant 24 charged to the low pressure circuit from the second port 12 can pass through the throttling device 6 and the auxiliary throttling device 5 and flow to the high pressure circuit. In addition, the total ratio of the medium boiling point refrigerant 24 and the low boiling point refrigerant 25 to the total weight of the refrigerant sealed in the container 20 is 50 mass % or less. In addition, the low pressure circuit has members with a relatively large volume (i.e., the evaporator 8, the outer tube 4b of the first heat exchanger 4, the outer tube 7b of the second heat exchanger 7, and the refrigerant tank 12). Therefore, even if the low boiling point refrigerant 25 and the medium boiling point refrigerant 24 are charged to the low pressure circuit from the second port 12, the pressure rise in the low pressure circuit is relatively suppressed. Therefore, after the low boiling point refrigerant 25 and the medium boiling point refrigerant 24 are charged into the low pressure circuit from the second port 12, the high boiling point refrigerant 23 can be charged into the low pressure circuit from the second port 12. That is, substantially the entire amount of refrigerant in the container 20 can be charged from the second port 12 instead of the first port 11. Depending on the type of compressor 1, the low pressure section of the compressor 1 may have a relatively large volume. In this case, the compressor 1 also becomes a member that constitutes the low pressure circuit and has a relatively large volume.

[0057] In addition, by charging the low boiling point refrigerant 25, the medium boiling point refrigerant 24 and the high boiling point refrigerant 23 from the second port 12 in this order, it is possible to effectively prevent the lubricating oil from accumulating and to improve the start-up performance of the compressor 1. This point will be described below.

[0058] When the refrigeration circuit 100 is stopped before the refrigerant is charged, the lubricating oil for lubricating the compressor 1 may remain in a low-temperature and large-volume portion, such as the evaporator 8, in a state where the temperature has dropped and the viscosity has increased. When the medium-boiling refrigerant is a hydrocarbon (e.g., ethane), the medium-boiling refrigerant 24, which is compatible with the lubricating oil for lubricating the compressor 1, can be charged to the low-pressure circuit. Therefore, the viscosity of the lubricating oil can be reduced by contacting the medium-boiling refrigerant 24 with the lubricating oil remaining in the evaporator 8. When the high-boiling refrigerant 23 is subsequently charged, the low-boiling refrigerant 25 and the medium-boiling refrigerant 24 that were previously charged pass through the throttling device 6 and the auxiliary throttling device 5 relatively easily and flow into the high-pressure circuit. At this time, the lubricating oil with reduced viscosity spreads throughout the entire refrigeration circuit 100 along with the refrigerant. In other words, the lubricating oil can be distributed throughout the refrigeration circuit.

[0059] At this time, the high boiling point refrigerant 23 is present in the low pressure circuit, and the low boiling point refrigerant 25 and the medium boiling point refrigerant 24 are present in the high pressure circuit. When the compressor 1 is started in this state, the refrigerant that is sucked in and compressed is mainly the high boiling point refrigerant 23. Since the high boiling point refrigerant 23 has a higher boiling point than the low boiling point refrigerant 25 and the medium boiling point refrigerant 24, the high boiling point refrigerant 23 will have a lower pressure than the low boiling point refrigerant 25 and the medium boiling point refrigerant 24 when they are in the same temperature environment. In other words, the discharge pressure of the compressor 1 does not become high at the time of startup, so it can be easily started up at a relatively low load.

[0060] As described above, the port to which the container 20 is first connected may be the first port 11 or the second port 12. The port to be first used when charging the refrigerant from the container 20 can be determined based on a detected state of the refrigeration circuit 100 or a refrigeration device including the refrigeration circuit 100.

[0061] That is, the state of the refrigeration circuit 100 or a refrigeration device including the refrigeration circuit 100 may be detected, and based on the detected state, the port 22 may be connected to the second port 12 instead of the first port 11. In this case, at least a part of the refrigerant in the container 20 is charged to the refrigeration circuit 100 through the second port 12 from the container 20 in an orientation in which the port 22 faces upward. Then, the orientation of the container 20 is changed to an orientation in which the port 22 faces downward, and the refrigerant remaining in the container 20 is charged.

[0062] The state of the refrigeration circuit 100 or a refrigeration device equipped with the refrigeration circuit 100 is detected by a temperature sensor attached to the refrigeration circuit 100 or the refrigeration device before the refrigerant is charged and when the refrigeration circuit 100 is operating.

[0063] An example of the relationship between the installation positions of the temperature sensors, the detection results of the temperature sensors, and the ports to which the refrigerant is charged is as shown in Table 1. When the refrigeration circuit 100 is applied to a cold storage such as an ultra-low temperature freezer, a temperature sensor that detects the temperature inside the storage is used for judgment in addition to the temperature sensors shown in Table 1. The case where the refrigeration circuit 100 is applied to a cold storage such as an ultra-low temperature freezer will be described below.

[0064] [Table 1]

[0065] When the refrigerant temperature at the outlet of the condenser 2 is higher than a predetermined value and the temperature inside the cabinet is higher than a predetermined value, that is, when the detection results of the temperature sensors of the condenser 2 outlet and the cabinet temperature indicate abnormally high temperatures, the following abnormality may occur. That is, there may be clogging with lubricating oil or impurities that may cause poor condensation in the inner tube 4a of the first heat exchanger 4. That is, there may be an abnormality in the high-pressure circuit (particularly the inner tube 4a of the first heat exchanger). The cause of clogging with lubricating oil or impurities may be poor condensation in the condenser 2 (for example, a failure of the fan motor). Therefore, in this case, the first port 11 is used to charge the refrigerant. By charging the refrigerant from the first port 11, the above-mentioned malfunction can be eliminated.

[0066] Also, when the refrigerant temperature at the inlet of the evaporator 8 is higher than a predetermined value and the temperature inside the cabinet is higher than a predetermined value, that is, when the detection results of the temperature sensors at the inlet of the evaporator 8 and the temperature inside the cabinet indicate abnormally high temperatures, the following abnormalities may have occurred. That is, the throttling device 6 or the high-pressure circuit may be clogged with lubricating oil or impurities. That is, an abnormality may have occurred in the high-pressure circuit. Therefore, in this case, the first port 11 is used to charge the refrigerant. By charging the refrigerant from the first port 11, the above-mentioned malfunctions can be eliminated.

[0067] Also, when the refrigerant temperature at the outlet of the evaporator 8 is higher than a predetermined value and the temperature inside the cabinet is higher than a predetermined value, that is, when the detection results of the temperature sensors of the outlet of the evaporator 8 and the temperature inside the cabinet indicate abnormally high temperatures, the following abnormalities may occur. That is, there is a possibility that the inside of the evaporator 8 or other parts of the low-pressure circuit are clogged with lubricating oil or impurities. Or, there is a possibility that lubricating oil is stagnating inside the evaporator 8. That is, there is a possibility that an abnormality has occurred in the low-pressure circuit. Therefore, in this case, the second port 12 is used to charge the refrigerant. By charging the refrigerant from the second port 12, the above-mentioned malfunction can be eliminated.

[0068] Also, when the refrigerant temperature at the inlet or outlet of the inner tube 4a of the first heat exchanger 4 is higher than a predetermined value and the temperature inside the cabinet is higher than a predetermined value, that is, when the detection results of the temperature sensors at the inlet or outlet of the inner tube 4a of the first heat exchanger 4 and the temperature inside the cabinet indicate abnormally high temperatures, the following abnormalities may occur. That is, the inner tube 4a of the first heat exchanger 4 may be clogged with lubricating oil or impurities that may cause poor condensation of the refrigerant. That is, an abnormality may occur in the high-pressure circuit (especially the inner tube 4a of the first heat exchanger). Therefore, in this case, the first port 11 is used to charge the refrigerant. By charging the refrigerant from the first port 11, the above-mentioned malfunction can be eliminated.

[0069] In addition, when the refrigerant temperature at the inlet or outlet of the outer tube 4b of the first heat exchanger 4 is higher than a predetermined value and the temperature inside the cabinet is higher than a predetermined value, that is, when the detection results of the temperature sensors at the inlet or outlet of the outer tube 4b of the first heat exchanger 4 and the temperature inside the cabinet indicate abnormally high temperatures, the following abnormalities may occur. That is, the outer tube 4b of the first heat exchanger 4 may be clogged with lubricating oil or impurities that may cause poor evaporation of the refrigerant. That is, an abnormality may occur in the low-pressure circuit (especially the outer tube 4b of the first heat exchanger). Therefore, in this case, the second port 12 is used to charge the refrigerant. By charging the refrigerant from the second port 12, the above-mentioned malfunction can be eliminated.

[0070] That is, when there is an abnormality in the temperature of the refrigerant flowing from the compressor 1 to the throttling device 6, the port 22 of the container 20 is connected to the first port 11 and the refrigerant is charged. Also, when there is an abnormality in the temperature of the refrigerant flowing from the throttling device 6 to the compressor 1, the port 22 of the container 20 is connected to the second port 12 and the refrigerant is charged. In other words, instead of connecting the port 22 of the container 20 to the first port 11, it is connected to the second port 12.

[0071] The detection result of the temperature sensor is recorded as a log in the control device of the refrigeration device. The control device may determine the port to charge the refrigerant based on the log and display the determination result on a display device provided in the refrigeration device. An operator can charge the refrigerant from the appropriate port by looking at this display.

[0072] The present disclosure is not limited to the embodiments described above, and various modifications are also included in the present disclosure without departing from the spirit of the present disclosure.

[0073] For example, the container 20 may contain an oil carrier agent 26 to be charged into the refrigeration circuit 100 together with the non-azeotropic refrigerant mixture as shown in Fig. 5. The container 20 may contain 0.14% by weight or more and 14% by weight or less of the oil carrier agent 26, with the total of the contents of the container 20 (i.e., the total of the non-azeotropic refrigerant mixture and the oil carrier agent 26) being 100% by weight. The oil carrier agent may be, for example, normal pentane or propane.

[0074] The oil carrier agent is liquid in the container 20 in a normal temperature environment. Since the oil carrier agent is in a liquid state, it mixes with the liquid high boiling point refrigerant 23. Therefore, when the container 20 is in a position in which the port 22 faces downward, the oil carrier agent is charged to the refrigeration circuit 100 together with the liquid high boiling point refrigerant 23. Therefore, by connecting the port 22 of the container 20 to the second port 12 and charging the refrigerant from the second port, the oil carrier agent can be brought into contact with the refrigerant stagnating in the low pressure circuit first. Therefore, the stagnating refrigerant can be quickly distributed throughout the refrigeration circuit 100. Furthermore, by using the container 20 in which the oil carrier agent is sealed in addition to the non-azeotropic refrigerant, the oil carrier agent can be charged to the refrigeration circuit 100 during the process of charging the refrigerant without performing a special process of charging the oil carrier agent.

[0075] The compressor 1 may be a compressor that does not require lubricating oil. In this case, the high boiling point refrigerant 23 is first charged from the first port 11, and then the low boiling point refrigerant 25 and the intermediate boiling point refrigerant 24 are charged from the second port 12. Since the low pressure circuit has a relatively large volume, the pressure rise in the low pressure circuit is suppressed to some extent. Since the high pressure circuit has a relatively small volume, the high boiling point refrigerant 23 flows from the high pressure circuit to the low pressure circuit through the throttling device 6 and the auxiliary throttling device 5. That is, the pressure rise in the high pressure circuit is suppressed to some extent. Therefore, the discharge pressure of the compressor 1 does not become high at the time of startup, so that the compressor 1 can be easily started up at a relatively low load even without lubricating oil.

[0076] Container 20 may also be provided with a skirt 27 as shown in Fig. 6. By providing skirt 27, container 20 can stably stand on its own horizontally even when port 22 faces downward. Also, a similar port 22 may be formed in a position symmetrical to port 22 (a portion corresponding to the bottom of container in Fig. 6). By providing skirt 27, the workability of charging refrigerant into refrigeration circuit 100 can be improved.

[0077] Moreover, the path switching device included in the jig 30 may be configured with one three-way valve instead of the two valves .

[0078] The refrigeration device may also include two refrigeration circuits 100.

[0079] In addition, in the case where the performance of the refrigeration circuit 100 can be fully utilized, the container 20 may not contain the low boiling point refrigerant 23, and may contain only the medium boiling point refrigerant 24 and the high boiling point refrigerant 25 as refrigerants constituting the non-azeotropic refrigerant mixture.

[0080] The disclosures of the specification, claims, drawings, and abstract contained in Japanese application No. 2022-54135, filed on March 29, 2022, are incorporated herein by reference in their entirety. [Industrial Applicability]

[0081] The present disclosure can be used in various refrigeration devices that use a non-azeotropic refrigerant as a refrigerant, such as ultralow temperature storage, ultralow temperature freezers, medicine refrigerators, blood refrigerators, and incubators. In addition, refrigeration devices used in environments without gravity (e.g., space environments) such as zero gravity and microgravity are equipped with compressors that do not require lubricating oil. The present disclosure can also be applied to refrigeration devices equipped with such compressors, and can therefore be used extremely effectively in industry. [Explanation of symbols]

[0082] 100 Refrigeration circuit 1 Compressor 2 Condenser 3 Gas-liquid separator 4 1st heat exchanger 4a inner tube 4b outer tube 5. Auxiliary squeeze device 6. Squeezing device 7 Second heat exchanger 7b Outer tube 8. Evaporator 9. Refrigerant tank 10. Refrigerant tank connection throttle device 11 First port 12 2nd port 20 containers 21 Container body 22 mouths 23 High boiling point refrigerants 24 Medium boiling point refrigerants 25 Low boiling point refrigerants 26 Oil carrier 27 Skirt 30 Jig 31 Container connection port 32 Branch piping 33 Port connection 34 Valve

Claims

1. A method for charging a refrigerant into a refrigeration circuit including a compressor, a condenser, a throttling device, an evaporator, and a first port disposed in a high-pressure portion of the compressor or downstream of the compressor and upstream of the throttling device, comprising: a container containing a refrigerant including a high-boiling-point refrigerant in a liquid state and a medium-boiling-point refrigerant in a wet gas state having a boiling point lower than that of the high-boiling-point refrigerant is connected to the first port; At least a portion of the refrigerant in the container is charged to the refrigeration circuit through the first port from the container in a position in which the mouth faces downward. A refrigerant charging method comprising:

2. The refrigeration circuit further includes a second port arranged in a low pressure portion of the compressor or upstream of the compressor and downstream of the throttling device. The refrigerant charging method according to claim 1.

3. After charging the refrigerant in the container to the refrigeration circuit via the first port, at least a portion of the refrigerant remaining in the container is charged from the container to the refrigeration circuit via the second port. The refrigerant charging method of claim 2 further comprising:

4. The method further includes connecting the opening of the container, the first port, and the second port with a jig including a branch pipe and a path switching device; Charging at least a portion of the refrigerant remaining in the container to the refrigeration circuit through the second port is performed by switching a path using the path switching device. The refrigerant charging method according to claim 3.

5. Detecting a state of the refrigeration circuit or a refrigeration device including the refrigeration circuit; connecting the port to the second port instead of the first port based on the detected condition; At least a portion of the refrigerant in the container is charged to the refrigeration circuit through the second port from the container in an orientation in which the mouth faces upward. The refrigerant charging method of claim 2 further comprising:

6. After charging at least a portion of the refrigerant in the container to the refrigeration circuit via the second port, at least a portion of the refrigerant remaining in the container is charged to the refrigeration circuit from the container in an orientation in which the mouth faces downward via the second port. The refrigerant charging method of claim 5 further comprising:

7. the detected condition is a temperature of the refrigerant flowing from the throttling device to the compressor; If the temperature is higher than a predetermined value, connecting the port to the second port instead of to the first port is performed. The refrigerant charging method according to claim 5 or 6.

8. by charging at least a portion of the refrigerant in the container to the refrigeration circuit through the second port, contacting at least a portion of the charged refrigerant with lubricating oil remaining in the evaporator; Reducing the viscosity of the lubricating oil; Permeating the lubricating oil through the refrigeration circuit; The refrigerant charging method of claim 3 further comprising:

9. The container further contains a low-boiling point refrigerant in a gaseous state having a boiling point lower than that of the intermediate-boiling point refrigerant. The refrigerant charging method according to claim 1.

10. The container contains 50% by weight or more and 80% by weight or less of the high-boiling point refrigerant, 10% by weight or more and less than 50% by weight of the medium-boiling point refrigerant, and 20% by weight or less of the low-boiling point refrigerant. The refrigerant charging method according to claim 9.

11. The high boiling point refrigerant is normal butane or isobutane, The intermediate boiling point refrigerant is ethane, ethylene, or xenon; The low boiling point refrigerant is methane or krypton. The refrigerant charging method according to claim 9 or 10.

12. The high boiling point refrigerant is normal butane, The intermediate boiling point refrigerant is ethane, The low boiling point refrigerant is methane. The refrigerant charging method according to claim 11.

13. The container further contains an oil carrier agent that is charged into the refrigeration circuit together with the refrigerant. The refrigerant charging method according to claim 1.

14. The container contains 0.14% by weight or more and 14% by weight or less of the oil carrier agent. The refrigerant charging method according to claim 13.

15. The oil carrier is normal pentane or propane. The refrigerant charging method according to claim 13 or 14.

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