Air extraction device

Abstract

Provided is an air ejecting device capable of efficiently ejecting air. The air ejecting device is provided with: an air ejecting pipe (71) connected to a condenser (12) and ejecting mixed gas containing refrigerant gas and air from the condenser (12); a separation membrane (23b) provided in the air ejecting pipe (71) and separating air from the mixed gas ejected from the air ejecting pipe (71) by pressure difference; an air discharge pipe (81) that guides gas containing air separated by the separation membrane (23b) to the outside; a first valve (24) provided in the air discharge pipe (81); a vacuum pump (27) provided at a position in the air discharge pipe (81) downstream of the first valve (24) and ejecting gas in the air discharge pipe (81) to the outside; and a control unit (50) that operates the vacuum pump (27) and makes the first valve (24) open, and when a predetermined amount of air is detected to have passed through the separation membrane (23b), makes the first valve (24) close and stops the passage of air due to pressure difference.

Description

Technical Field

[0001] This invention relates to an air extraction device. Background Technology

[0002] In refrigeration machines using refrigerant (so-called low-pressure refrigerant) where the operating pressure is partially negative, non-condensable gases such as air enter the machine from the negative pressure section and become trapped in the condenser after passing through the compressor. If these non-condensable gases remain in the condenser, the condensation performance of the refrigerant is hindered, thus reducing the performance of the refrigeration machine. Therefore, an extraction device is used to remove the refrigerant containing non-condensable gases from the refrigeration machine and discharge them outside, thereby ensuring a certain level of performance.

[0003] For example, the air extraction device described in Patent Document 1 is configured to install a gas separation membrane in the upper part of the air extraction tank, and the air extraction tank is separated into a refrigerator side and an external air side by the gas separation membrane. The external air side is made to be at low pressure by a vacuum pump, thereby discharging non-condensable gas into the atmosphere.

[0004] Prior art literature

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2008-96027 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] However, gas separation membranes come in several types, including: gas separation membranes that allow non-condensable gases to pass through easily but also allow a certain amount of refrigerant gas to pass through, making it impossible to efficiently separate the refrigerant gas from the non-condensable gas; and gas separation membranes that make it extremely difficult for refrigerant gas to pass through but also difficult for non-condensable gases to pass through.

[0009] When using the former gas separation membrane, although the amount of gas is very small compared to non-condensable gas, a small amount of refrigerant gas passes through along with the non-condensable gas.

[0010] When using the latter type of gas separation membrane, it may be impossible to adequately remove non-condensable gases. Furthermore, in such cases, to adequately remove the non-condensable gases, it is necessary to increase the partial pressure of the non-condensable gases within the system. However, increasing the partial pressure of the non-condensable gases (i.e., increasing the concentration of the non-condensable gases) will result in heat transfer resistance. One parameter indicating the degree of heat transfer resistance is the terminal temperature difference, but the terminal temperature difference... Figure 19The temperature rises as the concentration of the non-condensable gas increases. Furthermore, to minimize the impact of heat transfer resistance, the rate of increase in the terminal temperature difference, ΔT, needs to be kept within a specified temperature range (typically 1 K). Therefore, increasing the partial pressure of the non-condensable gas is not preferable. In this case, increasing the area of ​​the gas separation membrane can also be considered, but this method is also not preferred if miniaturization of the device is taken into account.

[0011] Here, "degree of rise" refers to the amount of temperature rise [K] based on the terminal temperature difference where the concentration of non-condensable gas is 0%.

[0012] However, by adding structures to the extraction device to compensate for the shortcomings of each gas separation membrane or by controlling it, the gas separation membranes can be used separately, thereby enabling the efficient discharge of non-condensable gases that utilize the characteristics of the gas separation membranes.

[0013] The present invention was made in view of this situation, and its object is to provide an air extraction device capable of simultaneously suppressing the amount of refrigerant leakage into the outside air and discharging non-condensable gases.

[0014] Solution for solving the problem

[0015] To address the aforementioned issues, the air extraction device of the present invention employs the following solution.

[0016] That is, one aspect of the present invention provides a gas extraction device comprising: an extraction pipe connected to a condenser, which extracts a mixture of refrigerant gas and non-condensable gas from the condenser; a separation membrane disposed on the extraction pipe, which separates non-condensable gas from the mixture extracted by the extraction pipe by means of a pressure difference; an exhaust pipe that guides gas containing the non-condensable gas separated by the separation membrane to the outside; a first valve disposed on the exhaust pipe; a vacuum pump disposed in the exhaust pipe downstream of the first valve, which discharges gas in the exhaust pipe to the outside; and a control unit that operates the vacuum pump to open the first valve, and closes the first valve when a predetermined amount of non-condensable gas is detected to have permeated through the separation membrane, thereby stopping the permeation of non-condensable gas caused by the pressure difference.

[0017] Invention Effects

[0018] According to the present invention, the air extraction device can simultaneously suppress the leakage of refrigerant into the outside air and discharge non-condensable gas. Attached Figure Description

[0019] Figure 1 This is a structural diagram of the air extraction device according to the first embodiment of the present invention.

[0020] Figure 2This is a structural diagram of the separate modules.

[0021] Figure 3 This is a structural diagram of the separation membrane.

[0022] Figure 4 It is a graph showing the changes in pressure and permeability associated with the operation of the vacuum pump and the opening and closing of the first valve.

[0023] Figure 5 It is a graph showing the change in terminal temperature difference.

[0024] Figure 6 This is a diagram showing the diffuser section of the compressor.

[0025] Figure 7 This is a diagram showing the diffuser section of the compressor.

[0026] Figure 8 This is a diagram showing the bends in the refrigerant piping.

[0027] Figure 9 This is a diagram showing the throttling section of the refrigerant piping.

[0028] Figure 10 This is a structural diagram of the air extraction device according to the second embodiment of the present invention.

[0029] Figure 11 It is a graph showing the changes in pressure and permeability associated with the operation of the vacuum pump, the opening and closing of the first valve, and the opening and closing of the second valve.

[0030] Figure 12 This is a diagram showing the membrane heating section of the air extraction device according to the third embodiment of the present invention.

[0031] Figure 13 This is a diagram showing another embodiment of the membrane heating section of the air extraction device according to the third embodiment of the present invention.

[0032] Figure 14 This is a structural diagram of the air extraction device of the first embodiment to the third embodiment of the modified example 1.

[0033] Figure 15 This is a structural diagram of the air extraction device according to the fourth embodiment of the present invention.

[0034] Figure 16 This is a graph showing the relationship between temperature (expressed as a reciprocal) and permeation velocity, categorized by gas type, when using a polyimide membrane as the separation membrane.

[0035] Figure 17 This is a structural diagram of the air extraction device of Modified Example 2 of the fourth embodiment of the present invention.

[0036] Figure 18This is a structural diagram of the air extraction device of Modified Example 3 of the fourth embodiment of the present invention.

[0037] Figure 19 It is a graph showing the relationship between air mass concentration and terminal temperature difference. Detailed Implementation

[0038] [First Implementation]

[0039] First, the air extraction device of the first embodiment of the present invention will be described with reference to the accompanying drawings.

[0040] [Structure of the Refrigeration Unit]

[0041] The structure of the refrigeration unit 10 will be described. For example... Figure 1 As shown, the refrigeration unit 10 has a compressor 11, a condenser 12, an expansion valve 13, an evaporator 14, and refrigerant piping 91, 92, 93, and 94 connecting these devices.

[0042] Compressor 11 is a device for compressing refrigerant. Compressor 11 is driven by a motor (not shown). Compressor 11 is, for example, a centrifugal compressor.

[0043] The condenser 12 is a device for condensing the high-temperature, high-pressure gaseous refrigerant compressed by the compressor 11. The condenser 12 is, for example, a shell-and-tube heat exchanger.

[0044] Multiple heat transfer tubes (not shown) for cooling medium are inserted into the condenser 12. A cooling medium (e.g., cooling water) for cooling the refrigerant flows inside the heat transfer tubes. Cooling water supplying the heat transfer tubes to the cooling medium is connected to pipe 16, and cooling water returning to pipe 17 after heat exchange is discharged. A temperature sensor (cooling medium temperature sensor 51) is installed in the cooling water return pipe 17 to measure the temperature Tc of the cooled water after heat exchange. For example, a resistive thermocouple is used as the sensor.

[0045] Expansion valve 13 is a device that expands the liquid refrigerant from condenser 12. The opening degree of expansion valve 13 can be adjusted and set appropriately according to specifications.

[0046] It should be noted that a secondary cooler (not shown) can also be installed between the condenser 12 and the expansion valve 13. The secondary cooler is a device for subcooling the refrigerant condensed by the condenser 12.

[0047] Evaporator 14 is a device that evaporates liquid refrigerant that has expanded through expansion valve 13. Evaporator 14 is, for example, a shell-and-tube heat exchanger.

[0048] Refrigerant piping 91 connects the refrigerant outlet of compressor 11 to the refrigerant inlet of condenser 12. Refrigerant piping 92 connects the refrigerant outlet of condenser 12 to expansion valve 13. Refrigerant piping 93 connects expansion valve 13 to refrigerant inlet of evaporator 14. Refrigerant piping 94 connects the refrigerant outlet of evaporator 14 to refrigerant inlet of compressor 11.

[0049] [Structure of the air extraction device]

[0050] The structure of the vacuum extraction device 20 will be described. The vacuum extraction device 20 is a device that releases non-condensable gas that has entered the refrigerant system of the refrigerator 10 and is retained in the condenser 12 to the outside. The non-condensable gas is, for example, air. In this embodiment, air will be used as an example for explanation.

[0051] The refrigerant used is a low-pressure refrigerant (e.g., R1233zd(E)). Therefore, during operation, the low-pressure section of the evaporator 14, etc., becomes below atmospheric pressure.

[0052] The vacuum pump 20 is located between the condenser 12 and the compressor 11. The vacuum pump 20 includes vacuum pipes 71 and 72, a separation device 21, exhaust pipes 81 and 82, and a vacuum pump 27.

[0053] One end of the extraction pipe 71 is connected to the condenser 12, and the other end is connected to the separator 21. Additionally, one end of the extraction pipe 72 is connected to the separator 21, and the other end is connected to the refrigerant pipe 91 or the compressor 11. This constitutes an extraction system.

[0054] The gas extraction system is configured such that the gas extracted from the condenser 12 (a mixture of refrigerant gas and air, hereinafter referred to as "mixed gas") is introduced to the separation device 21 via the extraction pipe 71, and after being processed by the separation device 21 as described later, it is returned to the refrigerant pipe 91 or compressor 11 located upstream of the condenser 12 via the extraction pipe 72.

[0055] It should be noted that during the operation of the refrigeration unit 10, the refrigerant piping 91 side or the compressor 11 side is usually at a higher pressure than the interior of the condenser 12. Therefore, it can also be assumed that the extracted mixed gas does not flow from the condenser 12 toward the refrigerant piping 91 side or the compressor 11 side.

[0056] However, in this embodiment, the extraction pipe 72 is configured to be connected to a predetermined location on the refrigerant pipe 91 or the compressor 11, so that the mixed gas flows from the condenser 12 toward the refrigerant pipe 91 side or the compressor 11 side. Detailed configuration will be described later.

[0057] This allows the air-separated gas mixture (mainly refrigerant gas) to return to the upstream side of the condenser 12.

[0058] A refrigerant temperature sensor 52 and an upstream pressure sensor 61 are installed on the extraction pipe 71. The refrigerant temperature sensor 52 measures the temperature Tb on the upstream side of the separation module 23 (separation membrane 23b) of the separation device 21. The upstream pressure sensor 61 measures the pressure Pb (total pressure) on the upstream side of the separation module 23 (separation membrane 23b) of the separation device 21.

[0059] One end of the exhaust pipe 81 is connected to the separation device 21, and the other end is connected to the vacuum pump 27. Additionally, one end of the exhaust pipe 82 is connected to the vacuum pump 27, and the other end is open to atmospheric pressure. This constitutes the exhaust system.

[0060] The exhaust system is configured to release the gas (mainly air) separated by the separator 21 to the outside of the extraction device 20 via exhaust pipes 81 and 82.

[0061] A first valve 24 is provided in the exhaust pipe 81. The first valve 24 can block the flow of gas in the exhaust pipe 81.

[0062] A third valve 26 is provided in the exhaust pipe 82. The third valve 26 can block the flow of gas in the exhaust pipe 82.

[0063] The separation device 21 is a device for separating air from a mixed gas introduced through the extraction pipe 71. The separation device 21 has a container 22 and a separation module 23.

[0064] The container 22 is box-shaped and has an internal space. The internal space houses the separation module 23.

[0065] like Figure 2 As shown, the separation module 23 has a cylindrical housing 23a and a plurality of separation membranes 23b.

[0066] The housing 23a has an air inlet 23c, an air outlet 23d, and an air outlet 23e.

[0067] The air extraction inlet 23c is connected to the air extraction piping 71. The air extraction outlet 23d is connected to the air extraction piping 72. The air outlet 23e is formed inside the container 22 and communicates with the space.

[0068] like Figure 3 As shown, one separation membrane 23b is configured as a cylinder. Separation membrane 23b is as follows... Figure 2 As shown, it is contained in the casing 23a in a bundled state. Figure 3As shown, the mixed gas introduced via the extraction pipe 71 flows inside the cylindrical separation membrane 23b. At this time, by making the pressure on the outer side of the separation membrane 23b lower than that on the inner side, air in the mixed gas flowing inside permeates to the outer side of the separation membrane 23b. That is, the separation membrane 23b utilizes the pressure difference generated between the upstream and downstream sides to separate air from the mixed gas.

[0069] Examples of materials that can be used for the separation membrane 23b include polyimide and zeolite.

[0070] These materials are not completely impermeable to refrigerant gas; rather, they allow a small amount of refrigerant gas to pass through along with the air. However, the rate of refrigerant gas passage is very slow compared to the rate of air passage.

[0071] In the separation device 21 configured as described above, the gas flows in the following manner.

[0072] That is, the mixed gas introduced into the separation device 21 via the extraction pipe 71 is introduced into the interior of the housing 23a through the extraction inlet 23c. The mixed gas introduced into the housing 23a flows inside the separation membrane 23b. At this time, if the pressure on the outside of the separation membrane 23b (i.e., the downstream side of the separation membrane 23b) is lower than the pressure on the inside of the separation membrane 23b (i.e., the upstream side of the separation membrane 23b), the air contained in the mixed gas flowing inside the separation membrane 23b permeates to the outside of the separation membrane 23b. The air separated from the mixed gas is discharged from the air outlet 23e into the space formed inside the container 22 and introduced into the exhaust pipe 81. On the other hand, the mixed gas (i.e., the refrigerant-rich gas) flowing inside the separation membrane 23b and separated from the air returns from the extraction outlet 23d through the extraction pipe 72 to the refrigerant pipe 91 or the compressor 11.

[0073] [Regarding methods for air removal]

[0074] The air extraction device 20 configured as described above is controlled, for example, in such a way that air that has entered the refrigerant system of the refrigerator 10 is released to the outside.

[0075] It should be noted that the operation of each valve, the start / stop of the vacuum pump, the acquisition of information from each sensor, and the calculation of each value described below are all performed by the control unit 50.

[0076] Here, the control unit 50 may consist of, for example, a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and a storage medium that can be read by a computer.

[0077] Furthermore, as an example, a series of processes used to implement various functions are stored in the form of a program on a storage medium, etc. The CPU reads the program from RAM, etc., and performs information processing / computation to realize various functions.

[0078] It should be noted that the program can also be applied in a way that it is pre-installed on ROM, other storage media, provided in a state that is stored on a storage medium that can be read by a computer, or transmitted via a wired or wireless communication unit.

[0079] Computers can read storage media such as hard disks, optical disks, CD-ROMs, DVD-ROMs, and semiconductor memories.

[0080] like Figure 4 As shown, the vacuum pump 27 stops, and the first valve 24 is closed, which is the state before air is discharged. Figure 4 (t0~t1 in the process). At this time, the partial pressure of the air upstream of the separation membrane 23b is constant. In addition, there is no pressure difference between the upstream and downstream sides of the separation membrane 23b, and no gas permeates.

[0081] Next, operate vacuum pump 27 ( Figure 4 (t1~t3). The third valve 26 is open. At this time, the partial pressure of the air upstream of the separation membrane 23b is constant. In addition, there is no pressure difference between the upstream and downstream sides of the separation membrane 23b, and no gas permeates.

[0082] It should be noted that the first valve 24 is not operated within a specified time period from the start of vacuum pump 27 operation. Figure 4 (t1 to t2 in the text). This is to ensure that all the gas in the exhaust pipes 81 and 82, which are located downstream of the first valve 24, is discharged.

[0083] Next, open the first valve 24 ( Figure 4 (t2 to t3 in the original text). At this time, a pressure difference is generated between the upstream and downstream sides of the separation membrane 23b. Accompanying this, air begins to permeate through the separation membrane 23b. As air permeates through the separation membrane 23b, the partial pressure of the air upstream of the separation membrane 23b decreases. Additionally, trace amounts of refrigerant gas begin to permeate over time.

[0084] It should be noted that the pressure difference is constant because the vacuum pump 27 is running. However, the amount of gas passing through the separation membrane 23b is not limited to the amount of gas discharged by the vacuum pump 27.

[0085] The permeability of air and refrigerant gas changes over time in the following ways.

[0086] The mixed gas present upstream of the separation membrane 23b includes refrigerant gas and air, but the proportion of air is very small compared to that of the refrigerant gas. Furthermore, the permeation rate of air is much faster than that of the refrigerant gas. Therefore, when a pressure difference arises between the upstream and downstream sides of the separation membrane 23b, the amount of air permeating increases sharply and then gradually decreases. On the other hand, the refrigerant gas permeates at a constant rate each time.

[0087] Based on the above, the earlier the separation process begins, the greater the air permeability and the smaller the refrigerant gas permeability. In other words, the earlier the separation process begins, the more efficiently air can pass through.

[0088] Next, the first valve 24 is closed, resulting in a state where there is no pressure difference between the upstream and downstream sides of the separation membrane 23b, thus eliminating gas permeation caused by the pressure difference. Figure 4 (t3~). At this time, since air has been removed through the separation membrane 23b, the partial pressure of the air upstream of the separation membrane 23b becomes higher than before the first valve 24 was opened. Figure 4 The pressure is low (t0~t2).

[0089] By repeatedly performing this batch process, the air that has entered the refrigerant system of the refrigerator 10 can be released to the outside.

[0090] The timing for closing the first valve 24 is preferably at the initial stage of permeation (separation) as described above. In this embodiment, the initial stage at which air permeation can be efficiently achieved is defined as when a predetermined amount of air is detected permeating the separation membrane.

[0091] The following describes a method for determining whether a specified amount of air has passed through the separation membrane.

[0092] [A time management method based on the first valve]

[0093] The amount of air passing through the separation membrane 23b when a specified pressure difference is applied is determined in advance through experiments, etc. Based on the results, the time for opening the first valve 24 is set. Figure 4 (The lengths of t2 to t3 in the diagram). Thus, by managing the opening time of the first valve 24, it can be determined that a specified amount of air has passed through the separation membrane 23b.

[0094] [A method based on the partial pressure of air upstream of the separation membrane]

[0095] like Figure 4 As shown, when the partial pressure of the air upstream of the separation membrane 23b is below a predetermined value, it is determined that a predetermined amount of air has permeated through the separation membrane 23b. The relationship between the predetermined value of the air partial pressure and the amount of air permeated is determined in advance through experiments, etc.

[0096] The partial pressure of air is calculated as follows.

[0097] First, the temperature Tb on the upstream side of the separation membrane 23b is measured using the refrigerant temperature sensor 52. Then, based on the refrigerant's physical properties, the saturation pressure of the refrigerant gas relative to temperature Tb is calculated, and this saturation pressure is taken as the partial pressure of the refrigerant gas.

[0098] Additionally, the pressure Pb on the upstream side of the separation membrane 23b is measured using the upstream pressure sensor 61. The partial pressure of the air is obtained by subtracting the partial pressure of the refrigerant gas from the total pressure Pb.

[0099] [Method based on terminal temperature difference]

[0100] The terminal temperature difference refers to the difference between the saturation temperature of condenser 12 and the outlet temperature of the cooling medium in condenser 12. Because air intrusion into condenser 12 reduces the condensation heat transfer rate, the terminal temperature difference becomes relatively larger. That is, the larger this value, the more air intrusion occurs. For example, ... Figure 5 As shown, in region A with a small terminal temperature difference, the amount of air intrusion is small. However, in regions B and C, the amount of air intrusion increases as the terminal temperature difference increases.

[0101] The temperature Td of condenser 12 (set as the saturation temperature inside condenser 12) is measured by condenser temperature sensor 53. In addition, the outlet temperature (temperature Tc) of the cooling medium of condenser 12 is measured by cooling medium temperature sensor 51.

[0102] Based on the above, it can be determined that a specified amount of air has passed through the separation membrane 23b based on the change in the terminal temperature difference (Td-Tc).

[0103] When it is determined by the methods described above that a specified amount of air has passed through the separation membrane 23b, the first valve 24 is closed by the control unit 50.

[0104] It should be noted that immediately after the first valve 24 is closed, the pressure in the space downstream of the first valve 24 to the separation membrane 23b is lower than the pressure upstream of the separation membrane 23b. Therefore, even after closing the first valve 24, the gas permeation will not immediately become zero; a small amount of gas will enter the space downstream of the first valve 24 to the separation membrane 23b before the pressure difference disappears. Therefore, by infinitely reducing the volume of the space downstream of the first valve 24 to the separation membrane 23b (ideally setting it to zero), the amount of gas permeating through the separation membrane 23b after the first valve 24 is closed can be reduced. This reduces the absolute amount of refrigerant gas permeating through the separation membrane 23b after the first valve 24 is closed.

[0105] As a method to reduce the volume of space, for example, there are methods to make the length of the exhaust pipe 81 on the upstream side of the first valve 24 shorter than the length of the exhaust pipe 81 on the downstream side of the first valve 24, and methods to make the flow path volume of the exhaust pipe 81 on the upstream side of the first valve 24 smaller than the flow path volume of the exhaust pipe 81 on the downstream side of the first valve 24.

[0106] [Connection points of the extraction piping]

[0107] Next, the specified part of the other end of the exhaust pipe 72 (the end opposite to the end connected to the separation device 21) will be described.

[0108] In this embodiment, the other end of the extraction pipe 72 is connected to the refrigerant pipe 91 or the compressor 11. Specifically, it is connected to a portion of the refrigerant flow path that has a static pressure lower than the static pressure inside the condenser 12. Thus, the mixed gas is configured to flow from the condenser 12 toward the refrigerant pipe 91 or the compressor 11.

[0109] The portion of the refrigerant flow path that has a lower static pressure than the static pressure inside the condenser 12, for example, Figure 6 and Figure 7 The diagram shows the flow path on the upstream side of the diffuser sections 91a and 91b of the centrifugal compressor 11.

[0110] In the upstream side of diffuser sections 91a and 91b, dynamic pressure dominates, and static pressure decreases. Therefore, the upstream side of diffuser sections 91a and 91b has a static pressure lower than that inside the condenser 12.

[0111] In addition, as another example of a refrigerant flow path that has a static pressure lower than that inside the condenser 12, there is a section where the refrigerant gas flow rate is accelerated.

[0112] For example, such as Figure 8 As shown, the portion where the flow rate is accelerated is the inner side of the bend 91c in the refrigerant piping 91. Inside the bend 91c, the refrigerant gas flow rate is accelerated, thus reducing the static pressure.

[0113] However, the static pressure increases at the site of delamination, so it is necessary to avoid areas where delamination is likely to occur.

[0114] In addition, such as Figure 9 As shown, the section where the flow velocity is accelerated is the throttling section 91d of the refrigerant piping 91. The throttling section 91d is the part where the piping diameter is reduced. In the throttling section 91d, the flow velocity of the refrigerant gas is accelerated, thus the static pressure decreases.

[0115] In this embodiment, the following effects are achieved.

[0116] The control unit 50 operates the vacuum pump 27, which opens the first valve 24. As a result, a pressure difference is generated at the separation membrane 23b by the vacuum pump 27, thereby extracting the air contained in the mixed gas.

[0117] In addition, when a predetermined amount of air is detected to have passed through the separation membrane 23b, the first valve 24 is closed to stop the air passage caused by the pressure difference, thereby allowing air to pass through only in the range where air can pass through efficiently (i.e., in the range where the amount of refrigerant gas passing through is small).

[0118] Furthermore, the control unit 50 determines that a predetermined amount of air has passed through the separation membrane 23b based on the time it takes for the first valve 24 to be in the open state. Therefore, it can determine whether a predetermined amount of air has passed through the separation membrane 23b based on the time it takes for the first valve 24 to be in the open state.

[0119] In addition, the control unit 50 determines that a specified amount of air has passed through the separation membrane 23b based on the measured values ​​of the upstream pressure sensor 61 and the refrigerant temperature sensor 52. Therefore, it can make a judgment related to the amount of air passing through based on the partial pressure of the air located upstream of the separation membrane 23b.

[0120] In addition, the control unit 50 determines that a specified amount of air has passed through the separation membrane based on the difference between the temperature sensor's measurement value and the saturation temperature of the condenser. Therefore, it can make a judgment related to the amount of air passing through based on the so-called terminal temperature difference of the condenser.

[0121] In addition, by returning the air-separated gas mixture (mainly refrigerant gas) to the upstream side of the condenser 12, the extracted refrigerant gas can contribute to refrigeration.

[0122] [Second Implementation]

[0123] Next, with reference to the accompanying drawings, the air extraction device of the second embodiment of the present invention will be described.

[0124] It should be noted that the air extraction device of this embodiment differs from the air extraction device of the first embodiment in terms of the structure of the air extraction system and the method of air discharge. Therefore, the same reference numerals are used to label the same structures and their descriptions are omitted.

[0125] [Structure of the air extraction device]

[0126] like Figure 10 As shown, a second valve 25 is provided in the exhaust pipe 81. The second valve 25 can block the flow of gas in the exhaust pipe 81.

[0127] A downstream pressure sensor 62 is installed on the exhaust pipe 81. The downstream pressure sensor 62 is located between the first valve 24 and the second valve 25. The downstream pressure sensor 62 measures the pressure Pe (total pressure) downstream of the first valve 24.

[0128] [Regarding methods for air removal]

[0129] The air extraction device 20, configured as described above, releases air that has entered the refrigerant system of the refrigerator 10 to the outside by controlling it in such a way as follows.

[0130] like Figure 11 As shown, the vacuum pump 27 stops, the first valve 24 closes, and the second valve 25 is closed, which is the state before air is discharged. Figure 11 (t0~t1 in the text). At this time, the partial pressure of the air upstream of the separation membrane 23b is constant. In addition, the pressure Pe is constant. Furthermore, there is no pressure difference between the upstream and downstream sides of the separation membrane 23b, and no gas permeates. In addition, the amount of gas accumulated in the space from the first valve 24 to the second valve 25 is constant.

[0131] Next, open the second valve 25 to start the vacuum pump 27. Figure 11 (t1 to t2 in the text). It should be noted that the third valve 26 is opened beforehand. At this time, the partial pressure of the air upstream of the separation membrane 23b is constant. In addition, the pressure Pe gradually decreases. Furthermore, there is no pressure difference between the upstream and downstream sides of the separation membrane 23b, and no gas permeates. In addition, the amount of gas accumulated in the space from the first valve 24 to the second valve 25 gradually decreases.

[0132] Next, if the pressure Pe decreases sufficiently, close the second valve 25 and stop the vacuum pump 27. Figure 4 (t2~t3). At this time, the partial pressure of the air on the upstream side of the separation membrane 23b is constant. In addition, the pressure Pe is higher than that before the vacuum pump 27 starts operating ( Figure 4The pressure is constant at low levels (t0~t1). Furthermore, there is no pressure difference between the upstream and downstream sides of the separation membrane 23b, and no gas permeates. Additionally, the amount of gas accumulated in the space from the first valve 24 to the second valve 25 is less than before the vacuum pump 27 is operated (…). Figure 11 The quantities of t0 to t1 in the equation are constant.

[0133] It should be noted that when a complete vacuum is applied, the amount of gas accumulated in the space from the first valve 24 to the second valve 25 becomes zero, and the pressure Pe also becomes zero.

[0134] Next, open the first valve 24 ( Figure 11 (t3 to t4 in the diagram). At this time, a pressure difference is generated between the upstream and downstream sides of the separation membrane 23b. Along with this, air begins to permeate through the separation membrane 23b. Additionally, a small amount of refrigerant gas begins to permeate over time. Furthermore, the gas that has permeated through the separation membrane 23b accumulates in the space from the downstream side of the separation membrane 23b to the second valve 25, thus the pressure Pe gradually increases and the pressure difference gradually decreases.

[0135] As air permeates through the separation membrane 23b, the partial pressure of the air upstream of the membrane 23b decreases. Here, pressure Pe is the total pressure of the air and refrigerant gas, but it is almost equal to the partial pressure of the air, with the partial pressure of the refrigerant gas being negligible compared to that of the air.

[0136] The permeability of air and refrigerant gas changes over time in the following ways.

[0137] The mixed gas present upstream of the separation membrane 23b contains refrigerant gas and air, but the proportion of air is very small compared to the refrigerant gas. Furthermore, the permeation velocity of air is much faster than that of refrigerant gas. Therefore, when a pressure difference arises between the upstream and downstream sides of the separation membrane 23b, the amount of air permeating increases sharply and then gradually decreases. On the other hand, the refrigerant gas permeates at a constant rate each time. It should be noted that since the refrigerant gas is inherently difficult to permeate through the separation membrane 23b, the amount of refrigerant gas accumulated is very small compared to the amount of air accumulated.

[0138] Based on the above, the earlier the separation process begins, the greater the air permeability and the smaller the refrigerant gas permeability. In other words, the earlier the separation process begins, the more efficiently air can pass through.

[0139] Next, the first valve 24 is closed, and there is no pressure difference between the upstream and downstream sides of the separation membrane 23b, eliminating the gas permeation caused by the pressure difference. Figure 11(t4~). At this time, since air has been removed at the separation membrane 23b, the partial pressure of air on the upstream side of the separation membrane 23b is higher than before the first valve 24 was opened ( Figure 11 The pressure Pe is kept constant at a lower level than that between t0 and t3. Additionally, the pressure Pe is maintained at a level lower than that after the vacuum pump 27 stops and before the first valve 24 opens ( Figure 11 The pressure is constant at t2 to t3.

[0140] The timing for closing the first valve 24 is the same as in the first embodiment.

[0141] In this state, by opening the second valve 25 and the third valve 26 to operate the vacuum pump 27, the separated air can be released to the outside.

[0142] By repeatedly performing this batch process, the air that has entered the refrigerant system of the refrigerator 10 can be released to the outside.

[0143] In this embodiment, the following effects are achieved.

[0144] Before starting the vacuum pump 27, the control unit 50 closes the first valve 24 and opens the second valve 25. After starting the vacuum pump 27 and before opening the first valve 24, the control unit 50 closes the second valve 25 and stops the vacuum pump 27. Therefore, the pressure difference between the pressure reduced by the vacuum pump 27 from the first valve 24 to the second valve 25 and the pressure on the upstream side of the separation membrane 23b can be used as the driving force required to allow air to pass through the separation membrane 23b.

[0145] Furthermore, by limiting the maximum amount of air that can permeate in a single process to the flow path volume of the exhaust pipe 81 from the separation membrane 23b to the second valve 25, the processing time is shortened, thus enabling a single process to be completed at the initial stage of permeation (separation). Therefore, air can be permeated efficiently.

[0146] [Third Implementation]

[0147] Next, with reference to the accompanying drawings, the air extraction device of the third embodiment of the present invention will be described.

[0148] It should be noted that the air extraction device of this embodiment differs from the air extraction devices of the first and second embodiments in that it includes a membrane heating unit for heating the separation membrane. Therefore, the same reference numerals are used to label the same structures and their descriptions are omitted.

[0149] like Figure 12As shown, the extraction device 20 includes a membrane heating unit 41. The membrane heating unit 41 is a device for heating the separation membrane 23b from the outside of the container 22. By heating the separation membrane 23b using the membrane heating unit 41, the mixed gas located inside the separation membrane 23b can be heated. The membrane heating unit 41 is heated, for example by electricity, and is a belt heater, halogen lamp heater, etc. The heat output of the membrane heating unit 41 is controlled by the control unit 50.

[0150] In addition, as other examples, such as Figure 13 As shown, the vacuum device 20 has a membrane heating section 42. The membrane heating section 42 is a pipe through which the high-temperature, high-pressure refrigerant discharged from the compressor 11 flows. The tubular membrane heating section 42 extends and protrudes from the outlet of the compressor 11 (or, the refrigerant piping 91 near the outlet), and connects to the refrigerant piping 91 after winding the container 22.

[0151] It should be noted that, instead of heating the separation membrane 23b, the membrane heating unit 41 can be used to heat the extraction pipe 71. This allows for the heating of the mixed gas flowing inside the extraction pipe 71.

[0152] According to this embodiment, the following effects are achieved.

[0153] The air extraction device 20 is equipped with membrane heating sections 41 and 42. Therefore, by heating the mixed gas inside the cylindrical separation membrane 23b, the molecular motion of air becomes more active (the diffusion rate of molecules increases), and air can easily pass through the separation membrane 23b.

[0154] [Variation Example 1]

[0155] like Figure 14 As shown, in the first to third embodiments, the destination of the extraction pipe 72 may also be the evaporator 14.

[0156] The structure of the extraction device 20 in the first to third embodiments described above is particularly suitable for employing a feature that allows refrigerant gas to pass through slightly along with air (specifically, such as...). Figure 4 , Figure 11 As shown, in the case of separation membrane 23b, when a pressure difference is generated between the upstream and downstream sides, the air permeation rate increases sharply and then gradually decreases, while the refrigerant gas permeation rate increases slightly and then becomes approximately constant. However, this does not preclude combinations with other separation membranes.

[0157] [Fourth Implementation]

[0158] Next, with reference to the accompanying drawings, the air extraction device of the fourth embodiment of the present invention will be described.

[0159] It should be noted that the air extraction device of this embodiment differs from the air extraction devices of the first to third embodiments in that it includes a membrane heating section for heating the separation membrane and a piping heating section for heating the air extraction piping. Therefore, the same reference numerals are used to label the same structures and their descriptions are omitted.

[0160] [Structure of the air extraction device]

[0161] like Figure 15 As shown, one end of the extraction pipe 72 is connected to the separation device 21, and the other end is connected to the evaporator 14. In addition, the extraction device 20 includes a film heating section 43 and / or a pipe heating section 44.

[0162] It should be noted that in this embodiment, the operation of the first valve 24 as described in the first to third embodiments is not a necessary structure and can be omitted.

[0163] Furthermore, polyimide can be used as a material for the separation membrane 23b. Compared to the separation membrane 23b provided in the vacuum device 20 of the first to third embodiments, these materials have the characteristic that it is difficult for refrigerant gas to pass through, but it is also difficult for air to pass through.

[0164] The membrane heating unit 43 is a device that heats the separation membrane 23b from the outside of the container 22. By heating the separation membrane 23b using the membrane heating unit 43, the mixed gas located inside the separation membrane 23b can be heated. The membrane heating unit 43 generates heat, for example, by electricity, and is a belt heater, halogen lamp heater, etc. The heat generated by the membrane heating unit 43 is controlled by the control unit 50.

[0165] The membrane heating unit 43 can increase the diffusion rate of molecular motion of the mixed gas by heating the mixed gas located inside the separation membrane 23b.

[0166] Therefore, the rate at which the air contained in the mixed gas permeates through the separation membrane 23b (hereinafter referred to as "permeation rate") can be increased. Compared with the case where the membrane heating section 43 is not provided, the amount of air permeating per unit time can be increased without increasing the area of ​​the separation membrane 23b.

[0167] exist Figure 16 (N. Tanihara, et al., Journal of the Japan Petroleum Institute, 59(6), 276-282 (2016)) shows a graph illustrating the relationship between temperature (expressed as the reciprocal) and permeation velocity according to the type of gas when using a polyimide membrane as the separation membrane 23b. According to this graph, it can be seen that... Figure 16Similarly, for the components of air (nitrogen (N2) and oxygen (O2)), the higher the temperature, the greater the permeation rate. This is because the diffusion rate of molecular motion increases with rising temperature.

[0168] The piping heating unit 44 is a device for heating the mixed gas flowing inside the extraction piping 71. The piping heating unit 44 generates heat, for example, by electricity, and is a belt heater, halogen lamp heater, etc. The heat output of the piping heating unit 44 is controlled by the control unit 50.

[0169] The piping heating unit 44 can directly heat the inside of the extraction piping 71, or indirectly heat the inside from the outside of the extraction piping 71.

[0170] By heating the piping heating unit 44, the phenomenon of condensation of saturated refrigerant gas due to external cooling from the extraction piping 71 can be suppressed, thereby preventing the extraction piping 71 from being blocked by condensed refrigerant gas.

[0171] Furthermore, heating the mixed gas can increase the diffusion rate of the air molecules contained in the mixed gas. The resulting effect is the same as that of the membrane heating unit 43.

[0172] In the air extraction device 20 of this embodiment, it is not necessary to provide both the membrane heating unit 43 and the piping heating unit 44; either one is sufficient.

[0173] However, the preferred piping heating section 44 is essential. This is because, if only the membrane heating section 43 is used, the extraction piping 71 may become clogged due to condensed gaseous refrigerant.

[0174] In addition, it is preferable to provide both a membrane heating section 43 and a piping heating section 44. The piping heating section 44, which is located on the upstream side, is used to preheat the mixed gas, and the heat generated by the membrane heating section 43 is used to compensate for the heat loss up to the separation device 21 (separation membrane 23b).

[0175] [Control methods for membrane heating units and / or piping heating units]

[0176] The air extraction device 20, configured as described above, releases the air that has intruded into the refrigerant system to the outside by operating the vacuum pump 27. At this time, the heat output of the film heating unit 43 and / or the piping heating unit 44 is adjusted in the following manner.

[0177] That is, the heat output of the membrane heating unit 43 and / or the piping heating unit 44 is adjusted based on the terminal temperature difference (Td-Tc).

[0178] It should be noted that the calculation of the terminal temperature difference and the management of heat generation are performed by the control unit 50.

[0179] Specifically, assuming the rise ΔT is kept within a specified temperature (e.g., below 1K), for example in an environment where the outside air temperature is low, such as winter, and the temperature of the extracted mixed gas is at least around 10°C, if the rise ΔT exceeds 1K, the air permeation is increased by increasing the heat output of the membrane heating unit 43 and / or the piping heating unit 44, thereby reducing the concentration of air contained in the mixed gas and keeping the rise ΔT below 1K (see reference). Figure 19 ).

[0180] In this way, by increasing the heat generation within the range required, it is possible to avoid increasing energy consumption or the load on the materials constituting the device.

[0181] Furthermore, provided that the rise ΔT is kept at a specified temperature (e.g., within 1K), for example, in an environment where the outside air temperature is high, such as in summer, the temperature of the extracted mixed gas is at most around 40°C, and the rise ΔT is very small (e.g., within 0.5K), the heat generation of the membrane heating unit 43 and / or the piping heating unit 44 can be reduced or stopped.

[0182] This avoids increasing energy consumption or the load on the materials constituting the device.

[0183] Here, in order to keep the rise in terminal temperature difference ΔT within 1K, an outlet gas temperature sensor 54 can be installed in the extraction pipe 72 to measure the temperature Tg of the mixed gas at the outlet side of the separation membrane 23b, and adjust the heat generation of the membrane heating unit 43 and / or the pipe heating unit 44 so that the temperature Tg converges within a specified temperature range. The specified temperature range will be described later.

[0184] This allows the rise ΔT to remain within 1K and the refrigerant gas permeation to remain within a specified value.

[0185] "Refrigerant gas permeation rate" is the amount of refrigerant gas that inevitably permeates through the separation membrane 23b and is discharged outside the system. If this permeation rate is within a specified value (e.g., within 7.85 × 10^3 [kg / day]), it is permissible as a vacuum device 20.

[0186] It should be noted that the outlet gas temperature sensor 54 is preferably installed in the extraction pipe 72 after the separation device 21. This is to minimize the influence of temperature changes caused by heat dissipation in the extraction pipe 72.

[0187] Here, "specified temperature range" is, for example, above 10°C and below 100°C. This value was obtained through experiments conducted by the inventors, but of course, its range can be appropriately changed according to the specifications of the separation membrane 23b.

[0188] Regarding the specified temperature range, a higher temperature range is more commonly used in winter compared to summer, for the following reasons.

[0189] That is, in winter, when the temperature of the extracted mixed gas is low due to the influence of the outside air temperature, the diffusion rate of the air molecules contained in the mixed gas is low, and the permeation rate of the separation membrane 23b is lower than in summer. On the other hand, the amount of air entering the system is greater than in summer. Therefore, in winter, compared with summer, there is a trend that the rate of increase in the terminal temperature difference ΔT is greater. Therefore, in winter, by setting the temperature range of the mixed gas higher than in summer, the diffusion rate of air molecules is increased.

[0190] [Modification Example 2]

[0191] The air extraction device 20 in this embodiment can also be applied to... Figure 17 The refrigerator 10 shown.

[0192] The refrigeration unit 10 has refrigerant pipes 92A and 92B instead of refrigerant pipe 92, and expansion valves 13A and 13B instead of expansion valve 13. An intercooler 15 is provided between expansion valves 13A and 13B. Furthermore, the refrigeration unit 10 includes a multi-stage compressor 11A and compressor 11B. The refrigeration unit 10 is configured such that the gaseous refrigerant separated from the intercooler 15 returns to the refrigerant pipe 96 between compressors 11A and 11B via refrigerant pipe 95.

[0193] [Modification Example 3]

[0194] like Figure 18 As shown, by adding the piping heating unit 44 to Figure 12 The exhaust pipe 71 of the exhaust device 20 shown can also be modified as in the structure of the exhaust device 20 of this embodiment.

[0195] In this embodiment, the following effects are achieved.

[0196] The extraction device 20 is equipped with a piping heating section 44, which can suppress the phenomenon of condensation of saturated refrigerant gas due to external cooling from the extraction piping 71, and prevent the extraction piping 71 from being blocked by condensed gaseous refrigerant.

[0197] In addition, by heating the mixed gas, the air permeation speed can be increased, and compared with the case without the piping heating unit 44, the amount of air per unit time can be increased without increasing the area of ​​the separation membrane 23b.

[0198] In addition, if the pumping device 20 also has a membrane heating unit 43, it can compensate for the heat loss of the mixed gas until it reaches the separation device 21 (separation membrane 23b).

[0199] In addition, the control unit 50 adjusts the heat output of the membrane heating unit 43 and / or the piping heating unit 44 based on the terminal temperature difference.

[0200] Specifically, the control unit 50 increases the heat generation when the rise ΔT exceeds 1K. This increases the heat generation within a range appropriate to the needs, thereby preventing increased energy consumption or increased load on the materials constituting the device.

[0201] Furthermore, when the rise ΔT is less than or equal to 0.5K, the control unit 50 reduces or stops the heat generation. This prevents an increase in energy consumption or a greater load on the materials constituting the device.

[0202] Additionally, the control unit 50 can adjust the heat output of the membrane heating unit 43 and / or the piping heating unit 44 to bring the temperature Tg of the mixed gas at the outlet of the separation membrane 23b within a specified temperature range. This allows the rise ΔT to be kept below 1 K and the refrigerant gas permeation rate to be kept below 7.85 × 10³ kg / day.

[0203] The structure of the extraction device 20 of the fourth embodiment described above is particularly suitable for cases where a separation membrane 23b is used, which has the characteristic of making it extremely difficult for refrigerant gas to pass through, but also difficult for air to pass through. However, combinations with other separation membranes are not excluded.

[0204] The embodiments described above are mastered as follows, for example.

[0205] That is, the gas extraction device 20 of one aspect of the present invention includes: extraction pipes 71 and 72 connected to a condenser 12, which extract a mixture of gas containing refrigerant gas and non-condensable gas from the condenser; a separation membrane 23b disposed on the extraction pipes, which separates non-condensable gas from the mixture extracted by the extraction pipes by means of a pressure difference; exhaust pipes 81 and 82, which guide the gas containing the non-condensable gas separated by the separation membrane to the outside; a first valve 24 disposed on the exhaust pipes; a vacuum pump 27 disposed in the exhaust pipes downstream of the first valve, which discharges the gas in the exhaust pipes to the outside; and a control unit 50, which operates the vacuum pump and opens the first valve, and closes the first valve when a predetermined amount of non-condensable gas is detected to have permeated through the separation membrane, thereby stopping the permeation of non-condensable gas caused by the pressure difference.

[0206] The extraction device according to this method comprises: an extraction pipe connected to a condenser, which extracts a mixture of refrigerant gas and non-condensable gas from the condenser; a separation membrane disposed on the extraction pipe, which separates non-condensable gas from the mixture extracted by the extraction pipe through a pressure difference; an exhaust pipe that guides gas containing the non-condensable gas separated by the separation membrane to the outside; a first valve disposed on the exhaust pipe; a vacuum pump disposed in the exhaust pipe downstream of the first valve, which discharges gas in the exhaust pipe to the outside; and a control unit that operates the vacuum pump and opens the first valve, thereby generating a pressure difference in the separation membrane by the vacuum pump, which can extract the non-condensable gas contained in the mixture.

[0207] Non-condensable gases include, for example, air.

[0208] Furthermore, the permeation rate of non-condensable gas, which constitutes a small proportion of the mixed gas, decreases over time after the valve is opened. On the other hand, the permeation rate of refrigerant gas, which constitutes a large proportion of the mixed gas and has a much slower permeation rate compared to non-condensable gas, increases slightly over time after the valve is opened, eventually becoming approximately constant. Therefore, the more efficient the non-condensable gas permeation is in the initial stage of permeation (separation), the more efficient it is. In this method, the first valve is closed when a predetermined amount of non-condensable gas is detected to have permeated the separation membrane, stopping the permeation of non-condensable gas caused by the pressure difference. This allows non-condensable gas to permeate only within the range where it can permeate efficiently (i.e., the range where the refrigerant gas permeation rate is low). Moreover, by repeatedly performing this process as a batch process, it is possible to allow a sufficient amount of non-condensable gas to permeate while suppressing refrigerant leakage to the outside air.

[0209] It should be noted that the specified amount of non-condensable gas (i.e., the range within which non-condensable gas can pass through efficiently) is determined in advance, for example, through testing.

[0210] In addition, one embodiment of the present invention provides a vacuum pumping device comprising a second valve 25 disposed between the first valve and the vacuum pump in the exhaust pipe. Before the vacuum pump is operated, the control unit closes the first valve and opens the second valve. After the vacuum pump is operated and before the first valve is opened, the control unit closes the second valve and stops the vacuum pump.

[0211] According to the pumping device of this method, a second valve is provided between a first valve and a vacuum pump in the exhaust pipe. Before the vacuum pump is started, the control unit closes the first valve and opens the second valve. After the vacuum pump is started but before the first valve is opened, the control unit closes the second valve and stops the vacuum pump. Therefore, the pressure from the first valve to the second valve reduced by the vacuum pump can be made into the pressure difference required for non-condensable gas to pass through the separation membrane.

[0212] Furthermore, by limiting the maximum amount of non-condensable gas that can permeate in a single process to the flow path volume of the exhaust pipe from the separation membrane to the second valve, the processing time is shortened, thus allowing a single process to be completed at the initial stage of permeation (separation). Therefore, non-condensable gas permeation can be achieved efficiently. Additionally, by repeatedly performing this process as a batch process, a sufficient amount of non-condensable gas can permeate while suppressing refrigerant leakage into the outside air.

[0213] In addition, in one embodiment of the present invention, the control unit determines that a predetermined amount of non-condensable gas has passed through the separation membrane based on the time it takes for the first valve to be in the open state.

[0214] According to the extraction device of this method, the control unit determines whether a predetermined amount of non-condensable gas has permeated the separation membrane based on the time it takes for the first valve to be opened. Therefore, it is possible to determine whether a predetermined amount of non-condensable gas has permeated the separation membrane based on the time it takes for the first valve to be opened. The relationship between the time it takes for the first valve to be opened and the amount of non-condensable gas permeating is determined in advance, for example, through experiments.

[0215] In addition, one embodiment of the present invention provides an extraction device comprising: a pressure sensor 61 disposed on the extraction pipe upstream of the separation membrane; and a refrigerant temperature sensor 52 disposed on the extraction pipe upstream of the separation membrane. The control unit determines, based on the measured values ​​of the pressure sensor and the refrigerant temperature sensor, that a predetermined amount of non-condensable gas has permeated through the separation membrane.

[0216] The extraction device according to this method includes: a pressure sensor installed on the extraction pipe upstream of the separation membrane; and a refrigerant temperature sensor installed on the extraction pipe upstream of the separation membrane. The control unit determines that a predetermined amount of non-condensable gas has passed through the separation membrane based on the measured values ​​of the pressure sensor and the refrigerant temperature sensor. Therefore, it is possible to make a judgment related to the amount of non-condensable gas passing through based on the partial pressure of the non-condensable gas located upstream of the separation membrane.

[0217] In addition, one embodiment of the present invention provides an extraction device that includes a cooling medium temperature sensor 51 installed at the cooling medium outlet of the condenser. The control unit determines, based on the temperature difference between the measured value of the cooling medium temperature sensor and the saturation temperature of the condenser, that a predetermined amount of non-condensable gas has passed through the separation membrane.

[0218] According to the extraction device of this method, a temperature sensor is provided at the cooling medium outlet of the condenser. The control unit determines that a predetermined amount of non-condensable gas has passed through the separation membrane based on the temperature difference between the measured value of the temperature sensor and the saturation temperature of the condenser. Therefore, it is possible to make a judgment related to the amount of non-condensable gas passing through based on the so-called terminal temperature difference of the condenser.

[0219] In addition, in one embodiment of the present invention, the length of the exhaust pipe upstream of the first valve is shorter than the length of the exhaust pipe downstream of the first valve.

[0220] According to the extraction device of this method, the length of the exhaust pipe upstream of the first valve is shorter than the length of the exhaust pipe downstream of the first valve, thus reducing the flow path volume of the exhaust pipe upstream of the first valve. Therefore, after the first valve is closed, the absolute amount of refrigerant gas (refrigerant gas passing through the separation membrane) entering the exhaust pipe upstream of the first valve can be reduced.

[0221] Furthermore, in one embodiment of the exhaust device of the present invention, the flow path volume of the exhaust pipe upstream of the first valve is smaller than the flow path volume of the exhaust pipe downstream of the first valve.

[0222] According to the extraction device of this method, the flow path volume of the exhaust pipe upstream of the first valve is smaller than the flow path volume of the exhaust pipe downstream of the first valve, thus reducing the flow path volume of the exhaust pipe upstream of the first valve. Therefore, after the first valve is closed, the absolute amount of refrigerant (refrigerant passing through the separation membrane) entering the exhaust pipe upstream of the first valve can be reduced.

[0223] In addition, in one embodiment of the present invention, the extraction pipe is connected to a low-pressure section of the refrigerant flow path guided to the condenser, wherein the low-pressure section is the section with a static pressure lower than that inside the condenser.

[0224] According to the extraction device of this method, the extraction piping is connected to the low-pressure section of the refrigerant flow path guided to the condenser. This low-pressure section has a lower static pressure than the static pressure inside the condenser, thus creating a pressure difference between the low-pressure section and the condenser. This allows the mixed gas (mainly refrigerant gas) that has separated from the non-condensable gases to return to the upstream side of the condenser. The returned refrigerant gas is then guided back to the condenser, thus enabling the extracted refrigerant gas to contribute to refrigeration.

[0225] In addition, in one embodiment of the present invention, the low-pressure section is the upstream side of the diffuser sections 91a and 91b of the compressor 11.

[0226] According to the extraction device of this method, the low-pressure section is the upstream side of the diffuser section of the compressor. The upstream side of the diffuser section of the compressor is the stage before the dynamic pressure is converted into static pressure, where the dynamic pressure is dominant and the static pressure is small, so it can be the section with a lower static pressure than the static pressure in the evaporator.

[0227] In addition, in one embodiment of the present invention, the low-pressure section is the section 91c, 91d that accelerates the flow rate of the refrigerant gas in the refrigerant flow path.

[0228] According to the extraction device of this method, the low-pressure section is the part where the refrigerant gas flow rate is accelerated in the refrigerant flow path. In the part where the refrigerant gas flow rate is accelerated, the dynamic pressure increases while the static pressure decreases, thus making it a section with a lower static pressure than the static pressure inside the evaporator.

[0229] In addition, in one embodiment of the present invention, the extraction pipe is connected to the evaporator 14.

[0230] According to the extraction device of this method, the other end of the extraction pipe is connected to the evaporator, thus enabling the mixed gas (mainly refrigerant gas) that has been separated from the non-condensable gas to return to the evaporator.

[0231] In addition, in one embodiment of the present invention, the separation membrane is cylindrical, and the extraction device includes membrane heating sections 41 and 42 for heating the mixed gas inside the cylindrical section.

[0232] According to the gas extraction device of this method, the separation membrane is cylindrical and has a membrane heating section for heating the mixed gas inside the cylinder. Therefore, by heating, the molecules of the non-condensable gas are made to move more actively and easily pass through the separation membrane.

[0233] In addition, in one embodiment of the present invention, the membrane heating unit 41 is a heater that is heated by electricity.

[0234] According to the air extraction device of this method, the membrane heating unit is a heater that generates heat by electricity, so the membrane heating unit can be set with a simple structure.

[0235] Membrane heating elements include, for example, belt heaters and halogen lamp heaters.

[0236] In addition, in one embodiment of the present invention, the membrane heating section 42 is a pipe through which the high-temperature refrigerant discharged from the compressor flows.

[0237] According to the extraction device of this method, the membrane heating section is a pipe through which the high-temperature and high-pressure refrigerant discharged from the compressor flows, so the membrane heating section can be installed without the need for a dedicated power supply, etc.

[0238] Additionally, one aspect of the present invention provides a gas extraction device comprising: an extraction pipe connected to a condenser, which extracts a mixture of refrigerant gas and non-condensable gas from the condenser; a separation membrane disposed on the extraction pipe, which separates non-condensable gas from the mixture extracted by the extraction pipe by means of a pressure difference; an exhaust pipe that guides gas containing the non-condensable gas separated by the separation membrane to the outside; a vacuum pump disposed on the exhaust pipe that discharges gas from the exhaust pipe to the outside; and a pipe heating unit 44 that heats the mixture located inside the extraction pipe upstream of the separation membrane.

[0239] According to the extraction device of this method, since it has a piping heating unit, it can suppress the phenomenon that the refrigerant gas in a saturated state condenses due to cooling from the outside of the extraction piping 71, thereby avoiding the phenomenon that the extraction piping 71 is blocked by the condensed gaseous refrigerant.

[0240] In addition, by heating the mixed gas, the air permeation speed can be increased, and compared with the case without the piping heating unit 44, the amount of air per unit time can be increased without increasing the area of ​​the separation membrane 23b.

[0241] Piping heating elements include, for example, belt heaters and halogen lamp heaters.

[0242] In addition, in one embodiment of the present invention, the separation membrane is cylindrical, and the extraction device includes a membrane heating section 43 for heating the mixed gas inside the cylindrical section.

[0243] According to the extraction device of this method, the separation membrane is cylindrical, and the extraction device has a membrane heating section for heating the mixed gas inside the cylindrical part, thus compensating for the heat loss of the mixed gas until it reaches the separation device (separation membrane).

[0244] Membrane heating elements include, for example, belt heaters and halogen lamp heaters.

[0245] In addition, one embodiment of the present invention provides a gas extraction device comprising: a gas extraction pipe connected to a condenser, which extracts a mixture of refrigerant gas and non-condensable gas from the condenser; a separation membrane disposed on the gas extraction pipe, which separates non-condensable gas from the mixture extracted from the gas extraction pipe by means of a pressure difference; an exhaust pipe that guides gas containing the non-condensable gas separated by the separation membrane to the outside; and a vacuum pump disposed on the exhaust pipe that discharges gas from the exhaust pipe to the outside. The separation membrane is cylindrical, and the gas extraction device includes a membrane heating section for heating the mixture inside the cylindrical section.

[0246] According to the extraction device of this method, the separation membrane is cylindrical, and the extraction device has a membrane heating section for heating the mixed gas inside the cylindrical section. Therefore, the air permeation rate can be increased. Compared with the case without the piping heating section 44, the air permeation per unit time can be increased without increasing the area of ​​the separation membrane 23b.

[0247] In addition, one embodiment of the present invention provides an air extraction device comprising a cooling medium temperature sensor disposed at the cooling medium outlet of the condenser; and a control unit that adjusts the heat generation of the piping heating unit and / or the film heating unit based on the temperature difference between the measured value of the cooling medium temperature sensor and the saturation temperature of the condenser.

[0248] The air extraction device according to this method includes: a cooling medium temperature sensor installed at the cooling medium outlet of the condenser; and a control unit that adjusts the heat generation of the piping heating unit and / or the film heating unit based on the temperature difference (terminal temperature difference) between the measured value of the cooling medium temperature sensor and the saturation temperature of the condenser, thereby avoiding increased energy consumption or increased load on the materials constituting the device.

[0249] In addition, in one embodiment of the present invention, the control unit increases the heat generation of the piping heating unit and / or the film heating unit when the temperature difference obtained by subtracting the measurement value of the cooling medium temperature sensor from the saturation temperature of the condenser exceeds 1K.

[0250] According to the extraction device of this method, when the temperature difference obtained by subtracting the measurement value of the cooling medium temperature sensor from the saturation temperature of the condenser increases by more than 1K, the control unit increases the heat generation of the piping heating unit and / or the film heating unit. Therefore, the heat generation can be increased within the range required, and the increase in energy consumption or the increase in load on the materials constituting the device can be avoided.

[0251] In addition, in one embodiment of the present invention, the control unit reduces or stops generating heat from the piping heating unit and / or the film heating unit when the temperature difference obtained by subtracting the measured value of the cooling medium temperature sensor from the saturation temperature of the condenser is less than 0.5K.

[0252] According to the extraction device of this method, when the temperature difference obtained by subtracting the measurement value of the cooling medium temperature sensor from the saturation temperature of the condenser rises by less than 0.5K, the control unit reduces or stops the heat generation of the piping heating unit and / or the film heating unit, thereby avoiding increased energy consumption or increased load on the materials constituting the device.

[0253] In addition, one aspect of the present invention provides an extraction device with an outlet gas temperature sensor disposed on the extraction pipe downstream of the separation membrane, and the control unit adjusts the heat generation of the pipe heating unit and / or the membrane heating unit in such a way that the measured value of the outlet gas temperature sensor is within a specified temperature range.

[0254] According to the extraction device of this method, an outlet gas temperature sensor is provided, and the control unit adjusts the heat generation of the piping heating unit and / or the membrane heating unit in such a way that the measured value of the outlet gas temperature sensor is within a specified temperature range. Therefore, the rise ΔT can be kept within 1K and the refrigerant gas permeation can be kept within 7.85×10^3 [kg / day].

[0255] The so-called "specified temperature range" is, for example, above 10°C and below 100°C.

[0256] Explanation of reference numerals in the attached figures

[0257] 10 Refrigeration units

[0258] 11, 11A, 11B compressors

[0259] 12 condensers

[0260] Expansion valves 13, 13A, and 13B

[0261] 14 Evaporator

[0262] 15 Intercooler

[0263] 16 Cooling water goes to the piping

[0264] 17 Cooling water return piping

[0265] 20 air extraction devices

[0266] 21 Separation Device

[0267] 22 containers

[0268] 23 Separation Module

[0269] 23a casing

[0270] 23b separation membrane

[0271] 23c air intake

[0272] 23d exhaust outlet

[0273] 23e air outlet

[0274] 24 First Valve

[0275] 25 Second Valve

[0276] 26 Third Valve

[0277] 27 Vacuum Pump

[0278] 41, 42, 43 Membrane heating section

[0279] 44 Piping Heating Section

[0280] 50 Control Department

[0281] 51 Cooling medium temperature sensor

[0282] 52 Refrigerant Temperature Sensor

[0283] 53 Condenser Temperature Sensor

[0284] 54 Outlet Gas Temperature Sensor

[0285] 61 Upstream pressure sensor

[0286] 62 Downstream pressure sensor

[0287] 71, 72 Extraction Piping

[0288] 81, 82 exhaust pipes

[0289] 91, 92, 92A, 92B, 93, 94, 95, 96 Refrigerant Piping

[0290] 91a Diffuser Section

[0291] 91b diffuser section

[0292] 91c bending section

[0293] 91d throttling section.

Claims

1. An air extraction device, wherein, The air extraction device includes: An extraction piping is connected to a condenser and extracts a mixture of refrigerant gas and non-condensable gas from the condenser. A separation membrane is disposed in the extraction pipe and separates non-condensable gases from the mixed gas extracted by the extraction pipe by means of a pressure difference. An exhaust pipe that directs gas containing the non-condensable gases separated by the separation membrane to the outside; The first valve is located in the exhaust pipe; A vacuum pump, located downstream of the first valve in the exhaust pipe, discharges gas from the exhaust pipe to the outside; and Control Department The control unit operates the vacuum pump and opens the first valve. When a predetermined amount of non-condensable gas is detected to have permeated the separation membrane, the control unit closes the first valve to stop the permeation of non-condensable gas caused by the pressure difference. The air extraction device includes a second valve disposed between the first valve and the vacuum pump in the exhaust pipe. Before operating the vacuum pump, the control unit closes the first valve and opens the second valve. The control unit closes the second valve and stops the vacuum pump after starting the vacuum pump and before opening the first valve.

2. The air extraction device according to claim 1, wherein, The control unit determines, based on the time it takes to open the first valve, that a predetermined amount of non-condensable gas has passed through the separation membrane.

3. The air extraction device according to claim 1, wherein, The air extraction device includes: A pressure sensor is disposed on the extraction pipe upstream of the separation membrane; and A refrigerant temperature sensor is installed on the extraction pipe upstream of the separation membrane. The control unit determines, based on the measured values ​​of the pressure sensor and the refrigerant temperature sensor, that a predetermined amount of non-condensable gas has passed through the separation membrane.

4. The air extraction device according to claim 1, wherein, The air extraction device includes a cooling medium temperature sensor located at the cooling medium outlet of the condenser. The control unit determines, based on the temperature difference between the measured value of the cooling medium temperature sensor and the saturation temperature of the condenser, that a predetermined amount of non-condensable gas has passed through the separation membrane.

5. The air extraction device according to any one of claims 1 to 4, wherein, The length of the exhaust pipe upstream of the first valve is shorter than the length of the exhaust pipe downstream of the first valve.

6. The air extraction device according to any one of claims 1 to 4, wherein, The flow path volume of the exhaust pipe upstream of the first valve is smaller than the flow path volume of the exhaust pipe downstream of the first valve.

7. The air extraction device according to any one of claims 1 to 4, wherein, The extraction piping is connected to the low-pressure section of the refrigerant flow path that is guided to the condenser. The low-pressure section is the part with a static pressure lower than that inside the condenser.

8. The air extraction device according to claim 7, wherein, The low-pressure section is located upstream of the diffuser section of the compressor.

9. The air extraction device according to claim 7, wherein, The low-pressure section is the part where the flow rate of refrigerant gas in the refrigerant flow path is accelerated.

10. The air extraction device according to any one of claims 1 to 4, wherein, The extraction piping is connected to the evaporator.

11. The air extraction device according to any one of claims 1 to 4, wherein, The separation membrane is cylindrical. The extraction device includes a membrane heating section for heating the mixed gas located inside the cylindrical shape.

12. The air extraction device according to claim 11, wherein, The membrane heating section is a heater that generates heat through electricity.

13. The air extraction device according to claim 11, wherein, The membrane heating section is a pipe through which the high-temperature refrigerant discharged from the compressor flows.

14. An air extraction device, wherein, The air extraction device includes: An extraction piping is connected to a condenser and extracts a mixture of refrigerant gas and non-condensable gas from the condenser. A separation membrane is disposed in the extraction pipe and separates non-condensable gases from the mixed gas extracted by the extraction pipe by means of a pressure difference. An exhaust pipe that directs gas containing the non-condensable gases separated by the separation membrane to the outside; A vacuum pump is installed in the exhaust pipe and discharges the gas in the exhaust pipe to the outside; A piping heating section heats the mixed gas inside the extraction piping located upstream of the separation membrane; A cooling medium temperature sensor is installed at the cooling medium outlet of the condenser; as well as Control Department The control unit adjusts the heat output of the piping heating unit based on the temperature difference between the measured value of the cooling medium temperature sensor and the saturation temperature of the condenser.

15. The air extraction device according to claim 14, wherein, The separation membrane is cylindrical. The extraction device includes a membrane heating section for heating the mixed gas located inside the cylindrical shape.

16. An air extraction device, wherein, The air extraction device includes: An extraction piping is connected to a condenser and extracts a mixture of refrigerant gas and non-condensable gas from the condenser. A separation membrane is disposed in the extraction pipe and separates non-condensable gases from the mixed gas extracted by the extraction pipe by means of a pressure difference. An exhaust pipe that directs gas containing the non-condensable gases separated by the separation membrane to the outside; A vacuum pump, which is installed in the exhaust pipe, discharges the gas in the exhaust pipe to the outside; A cooling medium temperature sensor is disposed at the cooling medium outlet of the condenser; and Control Department The separation membrane is cylindrical. The extraction device includes a membrane heating section for heating the mixed gas located inside the cylindrical shape. The control unit adjusts the heat output of the film heating unit based on the temperature difference between the measured value of the cooling medium temperature sensor and the saturation temperature of the condenser.

17. The air extraction device according to any one of claims 14 to 16, wherein, When the temperature difference obtained by subtracting the measurement value of the cooling medium temperature sensor from the saturation temperature of the condenser increases by more than 1K, the control unit increases the heat generation of the piping heating unit and / or the film heating unit.

18. The air extraction device according to any one of claims 14 to 16, wherein, When the temperature difference obtained by subtracting the measurement value of the cooling medium temperature sensor from the saturation temperature of the condenser increases by less than 0.5K, the control unit reduces the heat generation of the piping heating unit and / or the membrane heating unit or prevents the piping heating unit and / or the membrane heating unit from generating heat.

19. The air extraction device according to any one of claims 14 to 16, wherein, The extraction device includes an outlet gas temperature sensor located on the extraction pipe downstream of the separation membrane. The control unit adjusts the heat output of the piping heating unit and / or the membrane heating unit in a manner that keeps the measured value of the outlet gas temperature sensor within a specified temperature range.

Images