Air conditioner and pressure relief valve

Abstract

To provide an air conditioner and a pressure release valve that prevent fatigue breakdown due to pressure fluctuation of a compressor in normal times, and open when the internal pressure of the compressor reaches opening pressure.SOLUTION: An air conditioner comprises: a refrigeration cycle composed of a refrigerant circuit; and a pressure release valve that is provided in the refrigerant circuit and opens to release compressed gas inside the compressor to the outside when an internal pressure (P) of the compressor reaches a preset opening pressure (Pp). When a direction in which the compressed gas flows when the compressed gas is released to the outside is defined as a first direction, the pressure release valve has: a partition wall valve that is arranged upstream in the first direction, is in contact with the internal space of the compressor, and is affected by fluctuation in the internal pressure (P) of the compressor during normal operation of the compressor; and a high-pressure release valve that is arranged downstream of the partition wall valve in the first direction, and opens when the internal pressure (P) of the compressor reaches the preset opening pressure (Pp), where the high-pressure release valve and the partition wall valve are arranged in series along the first direction.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a pressure relief valve that prevents damage to a pressure vessel such as a compressor housing, and an air conditioner equipped with the pressure relief valve. [Background technology]

[0002] Conventionally, separate-type air conditioners, which are separated into an indoor unit and an outdoor unit, have been developed. In separate-type air conditioners, it is known that when the air conditioner is relocated or disposed of, a forced cooling operation called pump-down is performed in which all of the refrigerant in the refrigerant circuit is recovered in the outdoor unit.

[0003] If a large amount of air gets into the refrigerant circuit during pump-down for some reason, the air is compressed in the compressor, and the high-temperature, high-pressure air mixes with the refrigeration oil. As a result, the pressure in the compressor increases rapidly, and the compressor housing may be damaged.

[0004] In order to avoid the above damage, it may be considered to provide a pressure relief valve in the compressor.

[0005] For example, the pressure relief valve described in Patent Document 1 is attached to various pressure vessels, and releases the pressure inside the pressure vessel to the outside when the pressure inside the pressure vessel reaches or exceeds a set value.

[0006] The pressure relief valve described in Patent Document 1 is provided with an outer cylinder having an opening at its head, an inner cylinder fitted into the outer cylinder, and a rupture disc whose outer periphery is sandwiched by a packing to close the openings of both the outer cylinder and the inner cylinder. When the pressure inside the pressure vessel exceeds a set value, the rupture disc ruptures, opening the pressure relief valve and releasing the pressure inside the pressure vessel to the outside. This reduces the pressure inside the compression vessel and prevents damage to the pressure vessel. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 10-153299 Summary of the Invention [Problem to be solved by the invention]

[0008] The above-mentioned Patent Document 1 does not disclose the application of a pressure relief valve to an air conditioner.

[0009] The refrigerant circuit components that make up the refrigeration cycle include the heat exchanger, four-way valve, compressor, etc. In order to ensure safety, the pressure resistance of the refrigerant circuit components that make up the refrigeration cycle is designed to increase in order of the damage that would be caused by breakage. Of all the refrigerant circuit components, the compressor is the one that would be most susceptible to damage if broken, so it is designed to have the highest pressure resistance.

[0010] However, even if the compressor is designed to have a high pressure resistance, the housing of the compressor may be damaged in some cases. An example of such a case is when a large amount of air is mixed into the refrigerant circuit during the above-mentioned pump-down. In that case, the speed of pressure rise inside the compressor is fast, so the speed at which high-pressure gas propagates from the compressor to other refrigerant circuit components cannot keep up, and the pressure resistance of the compressor cannot withstand the pressure inside the compressor, which may damage the housing of the compressor. Note that when a large amount of air is mixed into the refrigerant circuit, the mixture of high-temperature and high-pressure air and refrigerating machine oil explodes in the compressor due to compression heat, which is called a "diesel explosion." If a diesel explosion occurs, the compressor may be damaged.

[0011] In view of this, it is conceivable to provide a pressure relief valve in the compressor as described above, but providing the pressure relief valve described in Patent Document 1 above poses the following problems.

[0012] Since a compressor is a device that compresses and discharges the sucked refrigerant, pressure fluctuations always occur inside the compressor during normal operation. Therefore, if the pressure relief valve described in Patent Document 1 is provided in the compressor, the pressure fluctuations inside the compressor are always applied to the rupture disk of the pressure relief valve. Therefore, there is a problem that the rupture disk may be fatigued and broken by the pressure fluctuations, and the pressure relief valve may open at a level lower than the intended set value, i.e., at a level of pressure fluctuation during normal operation.

[0013] The present disclosure has been made to solve such problems, and has an object to provide a pressure relief valve that prevents fatigue failure caused by normal pressure fluctuations inside a pressure vessel such as a compressor housing, and that opens when the pressure inside the pressure vessel reaches a preset set value, and an air conditioner equipped with a pressure relief valve. [Means for solving the problem]

[0014] The air conditioner according to the present disclosure includes a refrigeration cycle including a refrigerant circuit in which a compressor, an outdoor heat exchanger, a refrigerant pressure reducing device, and an indoor heat exchanger are connected by refrigerant piping, and a pressure relief valve that is provided in the refrigerant circuit and opens when a pressure (P) inside the compressor reaches a preset opening pressure (Pp) to release compressed gas inside the compressor to the outside, wherein when a flow direction of the compressed gas when the compressed gas is released to the outside is defined as a first direction, the pressure relief valve is disposed upstream in the first direction, contacts an internal space of the compressor, and is subjected to fluctuations in the internal pressure (P) of the compressor during normal operation of the compressor, and a high pressure release valve that is disposed downstream of the partition valve in the first direction and opens when the pressure (P) inside the compressor reaches the preset opening pressure (Pp), and the high pressure release valve and the partition valve are disposed in series along the first direction. , static pressure resistance or fatigue strength due to pressure fluctuations are different from each other. This is what we have in mind.

[0015] A pressure relief valve according to the present disclosure is provided in a pressure vessel, and opens when the pressure (P) inside the pressure vessel reaches a preset opening pressure (Pp) to release compressed gas inside the pressure vessel to the outside, wherein when a flow direction of the compressed gas when the compressed gas is released to the outside is defined as a first direction, the pressure relief valve comprises a partition valve that is arranged upstream in the first direction, contacts the space inside the pressure vessel, and is subjected to fluctuations in the pressure (P) inside the pressure vessel, and a high pressure release valve that is arranged downstream of the partition valve in the first direction and opens when the pressure (P) inside the pressure vessel reaches the preset opening pressure (Pp), and the high pressure release valve and the partition valve are arranged in series along the first direction. , static pressure resistance or fatigue strength due to pressure fluctuations are different from each other. This is what we have in mind. Effect of the Invention

[0016] According to the pressure release valve and air conditioner of the present disclosure, the pressure release valve prevents fatigue failure caused by pressure fluctuations during normal times inside a pressure vessel such as a compressor housing, and opens when the pressure inside the pressure vessel reaches a preset value. This ensures that the pressure release valve opens only when the pressure inside the pressure vessel rises to the preset value, thereby securing an open flow path for releasing the compressed gas inside the pressure vessel to the outside, and allows the pressure vessel to operate normally without affecting its original functions and performance during normal times. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a refrigerant circuit diagram showing the configuration of an air conditioner 1 according to a first embodiment. [Diagram 2] FIG. 2 is an explanatory diagram illustrating the function of a pressure release valve 20 provided in the air conditioner 1 according to the first embodiment. [Diagram 3] 1 is a cross-sectional view that shows typically a compressor 2 and a pressure release valve 20 provided in an air conditioner 1 according to Embodiment 1. FIG. [Figure 4] 1 is a perspective view showing the configuration of a pressure release valve 20 provided in the air conditioner 1 according to Embodiment 1. FIG. [Diagram 5] 1 is a cross-sectional view showing the configuration of a pressure release valve 20 provided in the air conditioner 1 according to Embodiment 1. FIG. [Figure 6] 4 is a cross-sectional view showing a modified example of the pressure release valve 20 according to the first embodiment. FIG. [Figure 7] 4 is an explanatory diagram showing the fatigue strength characteristics of the pressure relief valve 20. FIG. [Figure 8] 4 is an explanatory diagram showing fluctuations in the internal pressure (P) of the compressor 2. FIG. [Figure 9] 4 is a flowchart showing the process flow of the manufacturing method of the pressure release valve 20 according to the first embodiment. [Figure 10] 10 is a cross-sectional view showing the configuration of a pressure release valve 20 provided in an air conditioner 1 according to embodiment 2. FIG. [Figure 11] 11 is a cross-sectional view showing the configuration of a pressure release valve 20 provided in an air conditioner 1 according to embodiment 3. FIG. [Figure 12] 10 is a cross-sectional view showing the configuration of a pressure release valve 20 provided in an air conditioner 1 according to embodiment 4. FIG. [Figure 13] 11 is a cross-sectional view showing the configuration of a pressure release valve 20 provided in an air conditioner 1 according to embodiment 5. FIG. [Figure 14] 13 is a perspective view showing the configuration of a pressure release valve 20 provided in an air conditioner 1 according to embodiment 6. FIG. [Figure 15] 13 is a cross-sectional view showing the configuration of a pressure release valve 20 provided in an air conditioner 1 according to embodiment 6. FIG. [Figure 16] 13 is a cross-sectional view showing the configuration of a pressure release valve 20 provided in an air conditioner 1 according to embodiment 7. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of an air conditioner and a pressure release valve according to the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiment, and various modifications are possible without departing from the spirit of the present disclosure. The present disclosure also includes all combinations of possible configurations among the configurations shown in the following embodiment and its modified examples. In each drawing, the same reference numerals are used to denote the same or equivalent items, and this is common throughout the entire specification. In each drawing, the relative dimensional relationship or shape of each component may differ from the actual ones.

[0019] Embodiment 1 [Configuration of Air Conditioner 1] FIG. 1 is a refrigerant circuit diagram showing the configuration of an air conditioner 1 according to the first embodiment. As shown in FIG. 1, the air conditioner 1 is a separate type air conditioner composed of an outdoor unit 1a and an indoor unit 1b. The air conditioner 1 has a refrigeration cycle consisting of a refrigerant circuit in which a compressor 2, a muffler 3, a four-way switching valve 4, an outdoor heat exchanger 5, a refrigerant pressure reducing device 6, a liquid side shutoff valve 7, an indoor heat exchanger 8, and a gas side shutoff valve 9 are connected by a refrigerant piping 10. In addition, an outdoor blower 11 is installed in the outdoor heat exchanger 5 of the outdoor unit 1a, and an indoor blower 12 is installed in the indoor heat exchanger 8 of the indoor unit 1b. Note that the muffler 3, the four-way switching valve 4, the liquid side shutoff valve 7, and the gas side shutoff valve 9 are not necessarily provided in the refrigerant circuit, and may be provided as necessary.

[0020] The housing (not shown) of the outdoor unit 1a houses a compressor 2, a muffler 3, a four-way switching valve 4, an outdoor heat exchanger 5, a refrigerant pressure reducing device 6, a liquid side shut-off valve 7, a gas side shut-off valve 9, an outdoor blower 11, and a control unit 13. The housing (not shown) of the indoor unit 1b houses an indoor heat exchanger 8, an indoor blower 12, and a control unit 14. The indoor unit 1b is installed in the indoor space to be air-conditioned. On the other hand, the outdoor unit 1a is installed outside the indoor space. Below, each component of the air conditioner 1 shown in FIG. 1 will be briefly described.

[0021] The compressor 2 draws in the refrigerant flowing through the refrigerant pipe 10. The compressor 2 compresses the drawn refrigerant and discharges it to the refrigerant pipe 10. The compressor 2 is, for example, an inverter compressor. When the compressor 2 is an inverter compressor, the operating frequency may be changed arbitrarily by a drive circuit such as an inverter circuit, and the capacity of the compressor 2 that discharges the refrigerant per unit time may be changed. In this case, the operation of the drive circuit is controlled by the control unit 13. The refrigerant discharged from the compressor 2 flows into the outdoor heat exchanger 5 or the indoor heat exchanger 8. Specifically, when the air conditioner 1 is performing a cooling operation, the refrigerant discharged from the compressor 2 flows into the outdoor heat exchanger 5. On the other hand, when the air conditioner 1 is performing a heating operation, the refrigerant discharged from the compressor 2 flows into the indoor heat exchanger 8.

[0022] The compressor 2 has a housing 22 (see FIG. 3) made of a pressure vessel. In the first embodiment, a pressure release valve 20 (see FIG. 3) is provided on an upper surface 23 of the housing 22 of the compressor 2. The pressure release valve 20 is a valve that starts opening when the pressure inside the compressor 2 reaches a preset opening pressure (Pp) to release the high-pressure gas inside the compressor 2 to the outside. The installation position of the pressure release valve 20 is not limited to the compressor 2, and may be other places inside the outdoor unit 1a. The configuration of the pressure release valve 20 will be described later. In the present disclosure, the high-pressure gas inside the compressor 2 may be called compressed gas.

[0023] The outdoor heat exchanger 5 and the indoor heat exchanger 8 exchange heat between the refrigerant flowing therethrough and the air. The outdoor heat exchanger 5 and the indoor heat exchanger 8 are, for example, fin-and-tube type heat exchangers.

[0024] The outdoor heat exchanger 5 exchanges heat between the refrigerant flowing inside and the outdoor air blown by the outdoor blower 11. The outdoor heat exchanger 5 functions as a condenser during cooling operation, condensing and liquefying the refrigerant. The outdoor heat exchanger 5 functions as an evaporator during heating operation, evaporating and vaporizing the refrigerant.

[0025] The indoor heat exchanger 8 exchanges heat between the refrigerant flowing inside and the air in the indoor space blown by the indoor blower 12. The indoor heat exchanger 8 functions as an evaporator during cooling operation, evaporating and liquefying the refrigerant. The indoor heat exchanger 8 functions as a condenser during heating operation, condensing and liquefying the refrigerant.

[0026] The outdoor blower 11 has a fan motor 11a and a blade portion 11b. Similarly, the indoor blower 12 has a fan motor 12a and a blade portion 12b. The outdoor blower 11 and the indoor blower 12 blow air to the outdoor heat exchanger 5 and the indoor heat exchanger 8, respectively. The rotation speed of the outdoor blower 11 is controlled by the control unit 13, and the rotation speed of the indoor blower 12 is controlled by the control unit 14.

[0027] The four-way switching valve 4 is configured to switch between a cooling operation for cooling the indoor unit 1b side and a heating operation for heating the indoor unit 1b side. The four-way switching valve 4 is a flow path switching device that switches the flow of refrigerant depending on whether it is in cooling operation or heating operation. When the air conditioner 1 is performing cooling operation, the four-way switching valve 4 connects the discharge port of the compressor 2 to the outdoor heat exchanger 5 and also connects the suction port of the compressor 2 to the indoor heat exchanger 8. On the other hand, when the air conditioner 1 is performing heating operation, the four-way switching valve 4 connects the discharge port of the compressor 2 to the indoor heat exchanger 8 and also connects the suction port of the compressor 2 to the outdoor heat exchanger 5. The switching operation of the four-way switching valve 4 is performed under the control of the control unit 13.

[0028] The refrigerant decompression device 6 decompresses the refrigerant to expand it. The refrigerant decompression device 6 is configured with, for example, an electronic expansion valve. When the refrigerant decompression device 6 is configured with an electronic expansion valve, the opening degree is adjusted based on a command from the control unit 13. The refrigerant decompression device 6 is provided between the outdoor heat exchanger 5 and the indoor heat exchanger 8.

[0029] The muffler 3 is disposed on the discharge side of the compressor 2. In the example of FIG. 1, the muffler 3 is installed between the compressor 2 and the four-way switching valve 4. The muffler 3 serves to suppress the discharge pulsation of the compressor 2. The muffler 3 has a muffler space formed therein, which reduces noise generated by the discharge pulsation of the high-temperature, high-pressure refrigerant gas discharged from the discharge port of the compressor 2. Since the discharge pulsation becomes large when the compressor 2 is operating at a low speed, the muffler 3 is particularly effective when the compressor 2 is operating at a low speed.

[0030] The liquid side shut-off valve 7 is installed between the refrigerant pressure reducing device 6 and the indoor heat exchanger 8. The liquid side shut-off valve 7 is in a fully closed state when pump-down is performed. The opening and closing operation of the liquid side shut-off valve 7 may be performed manually by an operator performing the pump-down, or may be performed based on a command from the control unit 13 via the control unit 13.

[0031] The gas-side shut-off valve 9 is installed between the indoor heat exchanger 8 and the compressor 2. The gas-side shut-off valve 9 is in a fully open state when pump-down is performed. The opening and closing operation of the gas-side shut-off valve 9 may be performed manually by an operator performing pump-down, or may be performed based on a command from the control unit 13 via the control unit 13.

[0032] The control units 13 and 14 are each configured with, for example, a processor and a memory. In this case, the functions of the control units 13 and 14 are realized by the processor reading out a pre-stored program from the memory and executing it.

[0033] [Function of pressure relief valve 20] Before describing the configuration of the pressure release valve 20, the function of the pressure release valve 20 according to embodiment 1 will be described with reference to Figures 2 and 3. Figure 2 is an explanatory diagram illustrating the function of the pressure release valve 20 provided in the air conditioner 1 according to embodiment 1. Figure 3 is a cross-sectional view that typically shows the compressor 2 and pressure release valve 20 provided in the air conditioner 1 according to embodiment 1.

[0034] In Fig. 2, the horizontal axis indicates time, and the vertical axis indicates the pressure P inside the compressor 2. In Fig. 2, a solid line 30 is a graph showing the change in the pressure P inside the compressor 2. However, in Fig. 2, a dashed line 31 indicates the change in the pressure P when the compressor 2 is not provided with a pressure relief valve 20, and a dashed line 32 indicates the change in the pressure P when the compressor 2 is provided with a pressure relief valve 20. As shown by the solid line 30 in Fig. 2, the change in the pressure P inside the compressor 2 is basically the same up to a certain point, regardless of whether or not the pressure relief valve 20 is provided. After that, the change in the pressure P inside the compressor 2 differs due to the action of the pressure relief valve 20. This will be described in detail below.

[0035] First, as shown in the example of Fig. 3, the pressure relief valve 20 is provided, for example, on the upper surface 23 of the housing 22 of the compressor 2. In the example of Fig. 3, the pressure relief valve 20 is arranged so that the extension direction of the pressure relief valve 20 faces upward. The pressure relief valve 20 is designed to start opening when the pressure P inside the compressor 2 reaches the opening pressure Pp shown in Fig. 2.

[0036] The installation position and extension direction of the pressure release valve 20 on the compressor 2 are not limited to the case of FIG. 3. That is, the pressure release valve 20 may be installed on the side surface 24 of the compressor 2, and in that case, the extension direction of the pressure release valve 20 may be arranged in any direction toward up, down, left, or right. Alternatively, the pressure release valve 20 may be installed on the bottom surface 25 of the compressor 2, and in that case, the extension direction of the pressure release valve 20 may be arranged in any direction toward up, down, left, or right. Alternatively, the pressure release valve 20 may be arranged on the discharge pipe 21 provided at the discharge port of the compressor 2. In addition, since the pressure release valve 20 only needs to release the high-pressure gas to the outside of the refrigerant pipe 10, it may be installed not only in the compressor 2 but also at any position of the refrigerant circuit in the outdoor unit 1a. In this way, the installation position and extension direction of the pressure release valve 20 on the compressor 2 can be freely set as appropriate, so that the direction in which the high-pressure gas is released from the inside of the refrigerant pipe 10 to the outside can be freely set.

[0037] The function of the pressure relief valve 20 will now be described in detail with reference to FIG.

[0038] In FIG. 2, Pcomp is the design pressure of the compressor 2. The design pressure (Pcomp) is a pressure value to be used as a reference in design calculations for the strength of the compressor 2. The design pressure (Pcomp) is set to a value equal to or greater than the maximum pressure that can occur during normal operation of the compressor 2. The design pressure (Pcomp) is obtained by multiplying the maximum value of the pressure P that can occur during normal operation of the compressor 2 by a coefficient of 1 or more (e.g., 1.1). Alternatively, the design pressure (Pcomp) is obtained by adding a certain value (e.g., 0.1 MPa) to the maximum value of the pressure P that can occur during normal operation of the compressor 2.

[0039] 2, Pmax is the guaranteed pressure of the compressor 2. The guaranteed pressure (Pmax) is a value legally specified based on the design pressure (Pcomp) of the compressor 2. The guaranteed pressure (Pmax) is set to a value greater than the design pressure (Pcomp) of the compressor 2 based on the law.

[0040] In FIG. 2, P'max is the failure pressure of the compressor 2. The failure pressure (P'max) is a value that has a tolerance on the higher pressure side of the guaranteed pressure (Pmax). In other words, the failure pressure (P'max) is a value that is greater than the guaranteed pressure (Pmax). When the pressure inside the compressor 2 exceeds the failure pressure (P'max), the casing 22 of the compressor 2 may be damaged. The failure pressure (P'max) is obtained by durability testing of the compressor 2, etc.

[0041] As explained with reference to Fig. 1, the air conditioner 1 has a compressor 2. The compressor 2 is designed to ensure a legally stipulated guaranteed pressure (Pmax) based on the design pressure (Pcomp). Therefore, the breakdown pressure (P'max) of the compressor 2 is set to a value greater than the guaranteed pressure (Pmax).

[0042] As described above, when the air conditioner 1 is relocated or disposed of, pump-down is performed to recover the refrigerant in the refrigerant pipe 10 to the outdoor unit 1a. When pump-down is performed, the liquid-side shutoff valve 7 shown in FIG. 1 is fully closed and the gas-side shutoff valve 9 is fully opened to recover the refrigerant in the indoor unit 1b to the outdoor unit 1a, and forced cooling operation is performed. At this time, for example, if the outdoor unit 1a and the indoor unit 1b are already separated and the gas-side shutoff valve 9 is fully opened to perform forced cooling operation, a large amount of air is mixed into the refrigerant pipe 10. As a result, air compression occurs in the compressor 2, and the pressure (P) inside the compressor 2 rises sharply as shown by the solid line 30 in FIG. 2. At this time, as shown by the dashed line 31 in FIG. 2, if the pressure (P) inside the compressor 2 rises further and exceeds the damage pressure (P'max) of the compressor 2, the compressor 2 may be damaged.

[0043] Therefore, in the first embodiment, in order to prevent damage to the compressor 2, the outdoor unit 1a is provided with a pressure relief valve 20 that releases high-pressure gas to the outside of the refrigerant circuit. As shown in FIG. 2, when the pressure (P) inside the compressor 2 rises beyond the guaranteed pressure (Pmax) of the compressor 2 and reaches the opening pressure (Pp), the pressure relief valve 20 starts to open. As a result, the high-pressure gas inside the compressor 2 is released to the outside from the pressure relief valve 20, so that the pressure (P) inside the compressor 2 drops as shown by the broken line 32 in FIG. 2. The opening speed of the pressure relief valve 20 is faster than the pressure rise speed until the pressure (P) inside the compressor 2 reaches the damage pressure (P'max) of the compressor 2. Therefore, it is possible to secure a release flow path of the high-pressure gas toward the outside of the refrigerant pipe 10 before the pressure (P) reaches the damage pressure (P'max). This makes it possible to prevent damage to the compressor 2.

[0044] [Configuration of pressure relief valve 20] Next, the configuration of the pressure release valve 20 provided in the air conditioner 1 according to embodiment 1 will be described with reference to Figures 4 and 5. Figure 4 is a perspective view showing the configuration of the pressure release valve 20 provided in the air conditioner 1 according to embodiment 1. In Figure 4, for the purpose of explanation, some of the configuration is shown in transparent form with dashed lines. Figure 5 is a cross-sectional view showing the configuration of the pressure release valve 20 provided in the air conditioner 1 according to embodiment 1.

[0045] As shown in Figs. 4 and 5, the pressure relief valve 20 has a cylindrical shape, one end of which is open, and the other end of which is covered and closed by the high pressure relief valve 204. When the pressure relief valve 20 is opened, the high pressure gas flows in the direction indicated by the arrow A in Fig. 4 and is released to the outside. Hereinafter, the direction indicated by the arrow A will be referred to as the direction of flow of the high pressure gas, or the first direction. In the example of Figs. 4 and 5, as shown in Fig. 3, the pressure relief valve 20 is disposed on the upper surface 23 of the compressor 2, so the first direction is a direction from the bottom to the top of the paper. However, depending on the installation position of the pressure relief valve 20, the extension direction of the pressure relief valve 20 is not necessarily a direction from the bottom to the top. However, in the following, for the sake of simplicity, the open end of the pressure relief valve 20 will be referred to as the "lower end" and the closed other end of the pressure relief valve 20 will be referred to as the "upper end". The pressure relief valve 20 is made of a metal material such as stainless steel, copper, or a copper alloy.

[0046] As shown in FIG. 4, the pressure relief valve 20 is composed of a flow path portion 20a and a valve body portion 20b. The flow path portion 20a is composed of a partition valve pipe 201 and a high pressure relief valve pipe 203. The valve body portion 20b is composed of a partition valve 202 and a high pressure relief valve 204. The partition valve 202 is disposed in the partition valve pipe 201, and the high pressure relief valve 204 is disposed in the high pressure relief valve pipe 203. The partition valve 202 communicates with the inside of the compressor 2 and is subjected to pressure fluctuations inside the compressor 2. On the other hand, the high pressure relief valve 204 is protected by the partition valve 202 and is hardly affected by pressure fluctuations inside the compressor 2. The high pressure relief valve 204 starts opening when the pressure (P) inside the compressor 2 reaches an opening pressure (Pp). The configuration of the pressure relief valve 20 will be described in detail below.

[0047] [Configuration of the flow path portion 20a of the pressure relief valve 20] First, the flow path portion 20a of the pressure relief valve 20 will be described. As shown in FIG. 5, the partition valve pipe 201 and the high-pressure relief valve pipe 203 that constitute the flow path portion 20a are connected in series along the axial direction. The central axis of the partition valve pipe 201 and the central axis of the high-pressure relief valve pipe 203 are aligned, and the flow path portion 20a has a single cylindrical shape. The partition valve pipe 201 is arranged at the lower stage, and the high-pressure relief valve pipe 203 is arranged at the upper stage. The partition valve pipe 201 and the high-pressure relief valve pipe 203 are configured to be integrated. The partition valve pipe 201 and the high-pressure relief valve pipe 203 are joined by in-furnace brazing or the like. The outer diameter R1 of the partition valve pipe 201 and the outer diameter R2 of the high-pressure relief valve pipe 203 are the same. The inner wall of the flow path portion 20a has a stepped structure with two steps formed. Therefore, the wall thickness of the flow path portion 20a is, in order from top to bottom along the axial direction, three types of wall thicknesses T1, T2, and T3. The magnitude relationship of the three types of wall thicknesses T1, T2, and T3 satisfies T1 < T2 < T3. Therefore, in the flow path portion 20a, the inner diameter r1 of the lower end portion 201a of the partition valve pipe 201 is smaller than the inner diameter r2 of the upper end portion of the high-pressure relief valve pipe 203. This will be described in more detail.

[0048] The partition valve pipe 201 has a cylindrical shape, and the inner wall has a stepped structure along the axial direction. One step is formed on the inner wall of the partition valve pipe 201. The lower end 201a of the partition valve pipe 201 is open and communicates with the inside of the compressor 2. The first portion 201b on the lower end 201a side of the partition valve pipe 201 has a cylindrical shape with a plate thickness T3. The upper end 201c of the partition valve pipe 201 is open and communicates with the internal space of the high pressure release valve pipe 203. The second portion 201d on the upper end 201c side of the partition valve pipe 201 has a cylindrical shape with a plate thickness T2. A step portion 201e is provided at the boundary between the first portion 201b and the second portion 201d of the partition valve pipe 201. The step portion 201e may be disposed in the center of the partition valve pipe 201 in the axial direction, or may be disposed at a position shifted from the center toward the upper end 201c or the lower end 201a. However, the partition valve 202 is disposed in the step portion 201e as shown in FIG. 5. Therefore, the installation position of the step portion 201e may be appropriately set based on the axial length (height size) of the partition valve 202 so that the entire partition valve 202 is accommodated in the partition valve pipe 201. The partition valve 202 is fitted on the second part 201d side of the step portion 201e. Therefore, the lower end of the partition valve 202 abuts against the step portion 201e, and the partition valve 202 is prevented from falling below the step portion 201e. The step portion 201e also functions as a positioning member indicating the installation position of the partition valve 202. The partition valve 202 and the partition valve pipe 201 are joined together by furnace brazing or the like.

[0049] The pipe 203 for the high pressure release valve has a cylindrical shape, and the inner wall has a stepped structure along the axial direction. One step is formed on the inner wall of the pipe 203 for the high pressure release valve. The lower end 203a of the pipe 203 for the high pressure release valve is open and communicates with the internal space of the second part 201d of the pipe 201 for the bulkhead valve. The first part 203b on the lower end 203a side of the pipe 203 for the high pressure release valve has a cylindrical shape with a plate thickness T2. The upper end 203c of the pipe 203 for the high pressure release valve is open and serves as an opening of the pressure release valve 20. The second part 203d on the upper end 203c side of the pipe 203 for the high pressure release valve has a cylindrical shape with a plate thickness T1. A step part 203e is provided at the boundary between the first part 203b and the second part 203d of the pipe 203 for the high pressure release valve. The step portion 203e may be disposed in the center of the high pressure release valve pipe 203 in the axial direction, or may be disposed at a position shifted from the center toward the upper end 203c or the lower end 203a. However, the high pressure release valve 204 is disposed in the step portion 203e as shown in FIG. 5. Therefore, the installation position of the step portion 203e may be appropriately set based on the axial length (height) of the high pressure release valve 204 so that the entire high pressure release valve 204 is accommodated in the high pressure release valve pipe 203. The high pressure release valve 204 is fitted on the second part 203d side of the step portion 203e. Therefore, the lower end of the high pressure release valve 204 is abutted against the step portion 203e, and the high pressure release valve 204 is prevented from falling below the step portion 203e. The step portion 203e also functions as a positioning member indicating the installation position of the high pressure release valve 204. Moreover, the high pressure release valve 204 and the high pressure release valve pipe 203 are joined by furnace brazing, etc. The high pressure release valve 204 covers and closes the opening of the pressure release valve 20, as shown in FIG.

[0050] [Configuration of the valve body portion 20b of the pressure release valve 20] Next, the valve body portion 20b of the pressure relief valve 20 will be described. The valve body portion 20b is composed of a partition valve 202 and a high pressure release valve 204. The partition valve 202 is disposed upstream of the high pressure release valve 204 in the first direction, and is in contact with the space inside the compressor 2. The partition valve 202 is subjected to fluctuations in the pressure (P) inside the compressor 2 during normal operation of the compressor 2. The high pressure release valve 204 is disposed downstream of the partition valve 202 in the first direction, and opens when the pressure (P) inside the compressor 2 reaches a preset opening pressure (Pp).

[0051] The partition valve 202 and the high pressure release valve 204 have different static pressure resistance strength and fatigue strength. The static pressure resistance strength of the high pressure release valve 204 is higher than the static pressure resistance strength of the partition valve 202. On the other hand, the fatigue strength of the partition valve 202 is higher than the fatigue strength of the high pressure release valve 204. In the first embodiment, as shown in Fig. 5, the high pressure release valve 204 having a high static pressure resistance strength is disposed on the outer side of the compressor 2, and the partition valve 202 having a high fatigue strength is disposed on the inner side of the compressor 2. The high pressure release valve 204 and the partition valve 202 are disposed in series along the first direction.

[0052] The fatigue strength of the partition valve 202 is higher than that of the high pressure release valve 204. In order to prevent stress concentration, at least the upper surface 202a of the partition valve 202 has a curved shape and is formed into a cap type or a dome type. This increases the fatigue strength of the partition valve 202. On the other hand, the plate thickness D1 of the high pressure release valve 204 is thicker than the plate thickness D2 of the partition valve 202. As a result, when the high pressure release valve 204 and the partition valve 202 are made of the same material, the static pressure resistance strength of the high pressure release valve 204 is higher than the static pressure resistance strength of the partition valve 202. The partition valve 202 and the high pressure release valve 204 are made of metal materials such as stainless steel, copper, or copper alloy. In this way, in the first embodiment, the shapes and plate thicknesses of the partition valve 202 and the high pressure release valve 204 are changed to have different static pressure resistance strengths and fatigue strengths.

[0053] The partition valve 202 is constantly subjected to pressure fluctuations inside the compressor 2. However, since the partition valve 202 has a high fatigue strength, it has a long durability time until it is fatigue-destroyed by pressure fluctuations inside the compressor 2. Therefore, the partition valve 202 does not open at a low pressure level such as the normal operating range, unlike the pressure relief valve described in Patent Document 1. In addition, the high pressure release valve 204 is located outside the partition valve 202. Therefore, the high pressure release valve 204 is protected by the partition valve 202 and is hardly affected by pressure fluctuations inside the compressor 2. As a result, it is possible to suppress fatigue destruction of the high pressure release valve 204 due to pressure fluctuations inside the compressor 2.

[0054] 5, in the pressure relief valve 20, a partition valve pipe 201 and a partition valve 202 are disposed on the upstream side in the first direction. Also, a high pressure relief valve pipe 203 and a high pressure relief valve 204 are disposed on the downstream side in the first direction.

[0055] Although the partition valve 202 has been described as being formed in a cap type or a dome type, in more detail, the partition valve 202 is formed in a bottomed tubular shape. The partition valve 202 has a closed surface with a closed upper end and an open lower end. However, the upper surface 202a, which is the closed surface of the partition valve 202, is not flat but has a curved shape. The partition valve 202 is formed of a curved thin plate protruding in a direction from the inside of the compressor 2 toward the outside of the compressor 2. The curved shape of the partition valve 202 is, for example, a hemispherical shape. In this case, the curved shape of the partition valve 202 has an inner diameter and a curvature radius that are equal or approximately equal to those of the second portion 201d of the partition valve pipe 201. To specifically explain the curved shape of the partition valve 202, the lower end portion 202c of the partition valve 202 is circular in a plan view. The outer diameter of the circular shape of the lower end 202c is equal to or approximately equal to the inner diameter r3 of the second portion 201d. In addition, since the curved shape of the entire partition valve 202 is a hemispherical shape with a diameter r3, the radius of curvature is equal to or approximately equal to the radius of curvature of the inner wall surface of the second portion 201d. Note that the curved shape of the partition valve 202 is not limited to this case. FIG. 6 is a cross-sectional view showing a modified example of the pressure release valve 20 according to the first embodiment. As shown in FIG. 6, the size of the outer diameter may be the same as the inner diameter r3 of the second portion 201d, and the radius of curvature may be larger than that of the second portion 201d. In this case, the curved shape of the partition valve 202 is a more gentle curved shape than the hemispherical shape, as shown in FIG. 6. In addition, the curved shape of the partition valve 202 has a shorter axial length (i.e., a lower height h1) than the hemispherical shape. The partition valve 202 may be formed in a bottomed tubular shape with the upper surface 202a curved and the side surface 202b cylindrical, but the side surface 202b of the partition valve 202 may not be cylindrical. That is, the partition valve 202 may be formed in a spherical shape such as a hemispherical shape with the lower end 202c open and the side surface 202b and the upper surface 202a both being curved. In this case, the curvature of the spherical shape may not be constant and may change gradually along the way. Specifically, for example, the radius of curvature of the side surface 202b and the radius of curvature of the upper surface 202a may be different from each other.In the following description, the partition valves 202 that are cylindrical with a bottom and at least the upper surface of which is curved, and those that are spherical with an open lower end, will be collectively referred to as a cap type or a dome type.

[0056] The partition valve 202 is thus formed in a cap or dome shape with an open lower end and at least the upper surface 202a having a curved shape, and the lower end 202c of the partition valve 202 is joined to the inner wall surface of the stepped portion 201e of the partition valve pipe 201 over the entire circumferential length by furnace brazing or the like. Note that no flange or the like is provided on the outer periphery of the partition valve 202, as shown in Fig. 5. If a flange protruding outward in the horizontal direction were provided, stress would be concentrated on the flange, so the partition valve 202 is intentionally configured not to have a flange.

[0057] Since the partition wall valve 202 has a curved shape, stress concentration is small, and the reduction rate of fatigue strength determined by the stress concentration factor is small.

[0058] Fig. 7 is an explanatory diagram showing the fatigue strength characteristics of the pressure relief valve 20. In Fig. 7, the horizontal axis indicates the number of times the pressure fluctuation of the compressor 2 is repeated, and the vertical axis indicates the stress amplitude. In Fig. 7, a black circle 40 indicates the stress amplitude generated in the pressure relief valve when the partition valve 202 is not provided, a black triangle 41 indicates the stress amplitude generated in the partition valve 202, and a black star 42 indicates the stress amplitude generated in the high pressure relief valve 204. In Fig. 7, a first threshold value Th1 indicates the threshold value of the number of times of repetition required in the product specifications. In Fig. 7, the hatched portion is the region where the valve is destroyed by fatigue.

[0059] 7, in the case of a pressure relief valve not provided with the partition wall valve 202, the pressure relief valve is fatigue-destroyed at the time when the number of cycles reaches N1. The number of cycles N1 is a value smaller than the first threshold value Th1. Therefore, the pressure relief valve not provided with the partition wall valve 202 does not have sufficient fatigue strength and fatigue life in terms of product specifications.

[0060] On the one hand, as shown by the black triangle mark 41 in FIG. 7, the partition valve 202 undergoes fatigue failure when the number of repetitions reaches N2 times. The number of repetitions N2 is a value greater than the first threshold Th1. Also, as shown by the black star mark 42 in FIG. 7, when the number of repetitions reaches N2 times, the high-pressure relief valve 204 is not affected by the pressure fluctuations of the compressor 2 due to the partition valve 202, so the stress amplitude is hardly generated. Therefore, it can be seen that the pressure relief valve 20 provided with the partition valve 202 and the high-pressure relief valve 204 has sufficient fatigue strength and fatigue life in terms of product specifications. Thus, as shown in FIG. 7, by providing the partition valve 202 with a curved surface shape in the pressure relief valve 20, sufficient fatigue strength and fatigue life can be achieved in terms of product specifications.

[0061] In addition, as shown in FIG. 8, the design pressure (Pmax-s) of the partition valve 202 is equal to or higher than the legally specified guaranteed pressure (Pmax) and lower than the opening pressure (Pp) of the high-pressure relief valve 204. Details of FIG. 8 will be described later.

[0062] The high-pressure relief valve 204 is formed in a bottomed cylindrical shape. The high-pressure relief valve 204 has a closed surface with its upper end closed and its lower end open. However, as shown in FIG. 5, the upper surface 204a, which is the closed surface, of the high-pressure relief valve 204 is formed in a planar shape. The side surface portion 204d of the high-pressure relief valve 204 is cylindrical as shown in FIG. 4. Therefore, as shown in FIG. 5, the high-pressure relief valve 204 has a U-shaped cross-sectional shape in side view. Note that the high-pressure relief valve 204 is composed of a thin metal plate of the same material as the partition valve 202. Also, as shown in FIG. 5, no flange or the like is provided on the outer peripheral portion of the lower end portion 204c of the high-pressure relief valve 204. In the case of providing a flange protruding outward in the horizontal direction, stress concentrates on the flange, so the high-pressure relief valve 204 is deliberately configured not to have a flange.

[0063] The plate thickness D1 of the high-pressure relief valve 204 is thicker than the plate thickness D2 of the partition valve 202. That is, the relationship D1 > D2 is satisfied. Also, the plate thickness D1 of the high-pressure relief valve 204 is thinner than any of the plate thicknesses T1, T2, and T3 of the flow path portion 20a. That is, the relationship D1 < T1 < T2 < T3 is satisfied.

[0064] FIG. 8 is an explanatory diagram showing fluctuations in pressure (P) inside the compressor 2. FIG. 8 shows the graph of FIG. 2 in more detail. In FIG. 8, the horizontal axis represents time, and the vertical axis represents pressure (P). In FIG. 8, dashed line 31 represents changes in pressure (P) when the compressor 2 is not provided with a pressure relief valve 20, and dashed line 32 represents changes in pressure (P) when the compressor 2 is provided with a pressure relief valve 20. In addition, solid line 33 represents pressure fluctuations inside the compressor 2 when the compressor 2 is performing normal operation.

[0065] In the first embodiment, when the compressor 2 is operating normally, the pressure (P) inside the compressor 2 fluctuates within a relatively small range, as shown by the solid line 33 in Fig. 8. The pressure fluctuation is received by the partition valve 202, and the high pressure release valve 204 is hardly affected by the pressure fluctuation.

[0066] When a large amount of air enters the refrigerant pipe 10 due to the execution of pump-down or the like, the air is compressed inside the compressor 2. In that case, as shown by the solid line 30 in FIG. 8, the pressure (P) inside the compressor 2 rises. Then, when the pressure (P) inside the compressor 2 exceeds the guaranteed pressure (Pmax) of the compressor 2 and reaches the design pressure (Pmax-s) of the partition valve 202, the partition valve 202 opens. That is, the partition valve 202 is damaged. Furthermore, when the pressure (P) inside the compressor 2 rises and reaches the opening pressure (Pp) of the pressure release valve 20, the high pressure release valve 204 starts to open. That is, the high pressure release valve 204 starts to break. At this time, the opening speed of the high pressure release valve 204 is faster than the pressure rise speed until the pressure (P) inside the compressor 2 reaches the breakdown pressure (P'max) of the compressor 2. Therefore, before the pressure (P) reaches the damage pressure (P'max), the high pressure release valve 204 is opened, and the inside and outside of the housing 22 of the compressor 2 are communicated. This causes the high pressure gas to be released from the high pressure release valve 204 to the outside. As a result, as shown by the dashed line 32 in Fig. 8, the pressure (P) inside the compressor 2 drops suddenly. This makes it possible to prevent damage to the compressor 2.

[0067] The thicknesses T1, T2, and T3 of the flow passage portion 20a of the pressure release valve 20 are greater than the thicknesses D1 and D2 of the valve body portion 20b. Therefore, the static pressure resistance of the flow passage portion 20a is greater than the static pressure resistance of the valve body portion 20b. Therefore, even if the pressure release valve 20 opens and a large amount of refrigerant gas flows toward the pressure release valve 20, causing the pressure of the refrigerant gas in the flow passage portion 20a to increase, the shape of the flow passage portion 20a can be maintained. This makes it possible to avoid an increase in pressure loss in the flow passage portion 20a.

[0068] [Method of manufacturing the pressure relief valve 20] Next, there will be described a method for manufacturing the pressure release valve 20. Fig. 9 is a flow chart showing the flow of processes in the method for manufacturing the pressure release valve 20 according to the first embodiment.

[0069] Since the inner wall of the partition valve pipe 201 has a stepped structure, the inner diameter r3 of the upper end 201c of the partition valve pipe 201 is larger than the inner diameter r1 of the lower end 201a. Therefore, in step S1, the partition valve 202 is inserted into the partition valve pipe 201 starting from the upper end 201c which has the larger inner diameter (opening diameter). When the lower end 202c of the partition valve 202 abuts against the step of the step portion 201e, the step portion 201e prevents further insertion.

[0070] Furthermore, the inner diameter r2 of the upper end 203c of the high pressure release valve pipe 203 is larger than the inner diameter r3 of the lower end 203a. Therefore, in step S2, the high pressure release valve 204 is inserted into the high pressure release valve pipe 203 starting from the upper end 203c which has the larger inner diameter (opening diameter). When the lower end 204c of the high pressure release valve 204 abuts against the step of the stepped portion 203e, the stepped portion 203e prevents further insertion. Note that the order of performing steps S1 and S2 may be reversed.

[0071] Next, in step S3, the partition valve pipe 201 with the partition valve 202 inserted therein and the high pressure release valve pipe 203 with the high pressure release valve 204 inserted therein are joined by furnace brazing or the like. At this time, brazing is performed while the relative positions of the partition valve 202 and the high pressure release valve 204 are maintained by the step portions 201e and 203e provided in the flow path portion 20a. In this way, the partition valve pipe 201 and the high pressure release valve pipe 203 are joined. At the same time, the partition valve pipe 201 and the partition valve 202 are joined, and the high pressure release valve pipe 203 and the high pressure release valve 204 are joined. When the partition valve pipe 201 and the partition valve 202 are joined, the lower end portion 202c of the partition valve 202 is joined to the upper surface of the step of the step portion 201e. Alternatively, at the same time, at least a portion of the side surface portion 202b of the partition valve 202 and the inner wall of the step portion 201e may be joined. Similarly, when the high pressure release valve pipe 203 and the high pressure release valve 204 are joined, the lower end portion 204c of the high pressure release valve 204 and the upper surface of the step of the step portion 203e are joined. Alternatively, at the same time, at least a portion of the side surface portion 204d of the high pressure release valve 204 and the inner wall of the step portion 203e may be joined.

[0072] Through the above steps, the pressure relief valve 20 is manufactured.

[0073] As described above, in the first embodiment, the outdoor unit 1a is provided with the pressure release valve 20 in preparation for the occurrence of a diesel explosion during pump-down. The pressure release valve 20 is provided with the partition valve 202 having high fatigue strength and the high pressure release valve 204 having high static pressure resistance. The high pressure release valve 204 opens only when a large amount of air is mixed into the refrigerant pipe 10, air compression occurs in the compressor 2, and the pressure (P) in the compressor 2 rises rapidly and exceeds the guaranteed pressure (Pmax). This makes it possible to secure an opening flow path for releasing high pressure gas toward the outside of the refrigerant pipe 10, and to prevent damage to the compressor 2. During normal operation of the compressor 2, the partition valve 202 having high fatigue strength protects the high pressure release valve 204 by receiving pressure fluctuations inside the compressor 2, and therefore, fatigue failure of the high pressure release valve 204 can be prevented. Therefore, during normal operation, the compressor 2 can operate well without affecting its original functions and performance.

[0074] Embodiment 2 Fig. 10 is a cross-sectional view showing the configuration of the pressure release valve 20 provided in the air conditioner 1 according to embodiment 2. The difference between embodiment 2 and embodiment 1 is that in embodiment 2, a positioning portion consisting of convex portions 203f and 201f is provided on the joint surface between the partition valve pipe 201 and the high pressure release valve pipe 203. The other configurations are the same as in embodiment 1, so a description thereof will be omitted here.

[0075] 10, the partition valve pipe 201 and the high pressure release valve pipe 203 that constitute the flow path portion 20a of the pressure release valve 20 are joined by brazing or the like. At this time, in order to position the partition valve pipe 201 and the high pressure release valve pipe 203 that constitute the flow path portion 20a, a convex portion 203f and a convex portion 201f are provided in advance on a part of the joining surface.

[0076] In the example of Fig. 10, a convex portion 201f is provided on a part of the upper end portion 201c of the partition valve pipe 201, which is one of the joint surfaces. As shown in Fig. 10, the convex portion 201f is disposed near the inner wall of the flow path portion 20a. The convex portion 201f may be provided over the entire circumferential length of the upper end portion 201c, but may be provided at only one circumferential position of the upper end portion 201c as long as it is possible to position the upper end portion 201c in the radial direction. Alternatively, the convex portion 201f may be provided at two opposing circumferential positions of the upper end portion 201c.

[0077] In the example of FIG. 10, a convex portion 203f is provided in a part of the lower end portion 203a of the high pressure release valve pipe 203, which is another one of the joint surfaces. As shown in FIG. 10, the convex portion 203f is arranged near the outer wall of the flow path portion 20a. The convex portion 203f may be provided over the entire circumferential length of the lower end portion 203a, but may be provided at one or two circumferential positions of the lower end portion 203a as long as it can be positioned. In either case, however, the convex portion 203f is arranged at a position corresponding to the convex portion 201f. Since the convex portion 203f is arranged near the outer wall of the lower end portion 203a, the portion 203aa near the inner wall of the lower end portion 203a is a concave portion (female portion) that is concave toward the first direction with respect to the convex portion 203f. The concave portion (female portion) has a complementary shape to the convex portion 201f (male portion).

[0078] When the bulkhead valve pipe 201 and the high pressure release valve pipe 203 are joined, as shown in FIG. 10, the convex portion 201f is fitted to the radially inner side of the convex portion 203f arranged on the outside. That is, the convex portion 201f (male portion) is fitted to the part 203aa (female portion) close to the inner wall of the lower end portion 203a, which is a recess. In this way, one of the convex portion 203f and the convex portion 201f functions as a male portion, and the other functions as a female portion that receives the male portion. In this case, the part 203aa close to the inner wall of the lower end portion 203a functions as a female portion, and the convex portion 201f functions as a male portion. In this way, by mating the male portion and the female portion, the bulkhead valve pipe 201 and the high pressure release valve pipe 203 can be positioned in the axial direction and the radial direction. This makes it possible to prevent axial and radial misalignment between the partition valve pipe 201 and the high pressure release valve pipe 203.

[0079] In addition, although FIG. 10 shows a case where both the convex portion 203f and the convex portion 201f are provided, only one of the convex portion 203f and the convex portion 201f may be provided. That is, the convex portion may be provided only on one of the upper end portion 201c and the lower end portion 203a. In that case, a recess or an insertion hole of a complementary shape into which the convex portion is inserted is disposed on the other of the upper end portion 201c and the lower end portion 203a. In this case, the convex portion becomes a male portion, and the recess or the insertion hole becomes a female portion.

[0080] As described above, in the second embodiment as well, similar to the first embodiment, the outdoor unit 1a of the air conditioner 1 is provided with the pressure release valve 20, and therefore the same effects as those of the first embodiment can be obtained.

[0081] In the second embodiment, a positioning portion for performing axial and radial positioning is provided on the joining surface when the partition valve pipe 201 and the high pressure release valve pipe 203 constituting the flow passage portion 20a are joined. The positioning portion is composed of a male portion provided on one of the joining surfaces when the partition valve pipe 201 and the high pressure release valve pipe 203 are joined, and a female portion provided on the other of the joining surfaces and having a complementary shape to the male portion. This makes it easy to perform axial and radial positioning between the partition valve pipe 201 and the high pressure release valve pipe 203. Since the positioning is thus easy, the assembly work of the high pressure release valve 204 and the partition valve 202 is easy. This allows the high pressure release valve 204 and the partition valve 202 to be manufactured and stored individually. In addition, the strength characteristics of the high pressure release valve 204 and the partition valve 202 can be appropriately selected according to the pressure characteristics of the compressor 2 to which the pressure release valve 20 is attached, so that the pressure release valve 20 can be easily manufactured with high accuracy.

[0082] Embodiment 3 Fig. 11 is a cross-sectional view showing the configuration of a pressure release valve 20 provided in an air conditioner 1 according to embodiment 3. The difference between embodiment 3 and embodiment 1 is that in embodiment 3, the inner diameter of the high pressure release valve pipe 203 is enlarged, and at least a part of the downstream end of the partition valve pipe 201 is inserted and joined to the upstream end of the high pressure release valve pipe 203. The other configuration is the same as in embodiment 1, so a description thereof will be omitted here.

[0083] In the third embodiment, as shown in Fig. 11, a portion 203g on the lower end 203a side of the first portion 203b of the high pressure release valve pipe 203 is processed to widen its inner diameter. As a result, the inner diameter r4 of the portion 203g is equal to the outer diameter R1 of the partition valve pipe 201. Meanwhile, the outer diameter R3 of the portion 203g is naturally larger than the outer diameter R1 of the partition valve pipe 201. Also, the plate thickness of the portion 203g is equal to the plate thickness T2 of the first portion 203b of the high pressure release valve pipe 203.

[0084] Therefore, at least a part of the second part 201d of the partition valve pipe 201 is inserted into the part 203g in the direction of the arrow B. After the insertion, the high pressure release valve pipe 203 and the partition valve pipe 201 are joined by furnace brazing or the like.

[0085] As described above, in the third embodiment as well, similar to the first embodiment, the outdoor unit 1a of the air conditioner 1 is provided with the pressure release valve 20, and therefore the same effects as those of the first embodiment can be obtained.

[0086] In the third embodiment, the inner diameter of the high pressure release valve pipe 203 is enlarged, and a portion of the partition wall valve pipe 201 is inserted into and joined to the high pressure release valve pipe 203. This allows the high pressure release valve 204 and the partition wall valve 202 to be manufactured and stored separately. Also, the strength characteristics of the high pressure release valve 204 and the partition wall valve 202 can be appropriately selected according to the pressure characteristics of the compressor 2 to which the pressure release valve 20 is attached, allowing the pressure release valve 20 to be manufactured with high accuracy.

[0087] Embodiment 4 12 is a cross-sectional view showing the configuration of the pressure release valve 20 provided in the air conditioner 1 according to embodiment 4. The difference between embodiment 4 and embodiment 1 is that in embodiment 4, the high pressure release valve 204 and the partition wall valve 202 have the same shape, but are made of different materials for the high pressure release valve 204 and the partition wall valve 202. As the other configurations are the same as those in embodiment 1, their explanations will be omitted here.

[0088] In the above-mentioned first to third embodiments, an example is shown in which the difference in static pressure resistance and fatigue strength between the high pressure release valve 204 and the partition wall valve 202 is realized by the difference in shape between the high pressure release valve 204 and the partition wall valve 202. In the fourth embodiment, by changing the materials used for the high pressure release valve 204 and the partition wall valve 202, the static pressure resistance strength of the high pressure release valve 204 is increased and the fatigue strength of the partition wall valve 202 is increased.

[0089] Generally, aluminum alloys have higher fatigue strength than copper or copper alloys, so partition valve 202 is made of, for example, an aluminum alloy. Also, copper has higher static pressure resistance than aluminum, so high pressure release valve 204 is made of copper. Thus, in the fourth embodiment, partition valve 202 is made of a metal with high fatigue strength, and high pressure release valve 204 is made of a metal with high static pressure resistance.

[0090] When the plate thickness D2 of the partition valve 202 and the plate thickness D1 of the high pressure release valve 204 are equal, the partition valve 202 may be made of a material having a lower tensile strength than the high pressure release valve 204 .

[0091] Furthermore, in the fourth embodiment, an example has been described in which the high pressure release valve 204 and the partition valve 202 have the same shape, but this is not the only case, and the shapes of the high pressure release valve 204 and the partition valve 202 may be the same as those of the first to third embodiments. Even in this case, by using different materials for the high pressure release valve 204 and the partition valve 202, the fatigue strength of the partition valve 202 is further increased, and the static pressure resistance strength of the high pressure release valve 204 is also increased.

[0092] As described above, in embodiment 4, as in embodiment 1, the outdoor unit 1a of the air conditioner 1 is provided with a pressure release valve 20 composed of a partition valve 202 with high fatigue strength and a high-pressure release valve 204 with high static pressure resistance strength, and therefore the same effects as in embodiment 1 can be obtained.

[0093] Furthermore, in the fourth embodiment, since different materials are used for the high pressure release valve 204 and the partition valve 202, the strength characteristics of the high pressure release valve 204 and the partition valve 202 can be appropriately selected to manufacture the pressure release valve 20 with high precision. This allows the pressure release valve 20 to be manufactured easily and at low manufacturing costs without having to increase the machining precision of the high pressure release valve 204, the partition valve 202, and the parts to which they are attached.

[0094] Embodiment 5. Fig. 13 is a cross-sectional view showing the configuration of the pressure release valve 20 provided in the air conditioner 1 according to embodiment 5. The difference between embodiment 5 and embodiment 1 is that in embodiment 5, the space 20c between the high pressure release valve 204 and the partition wall valve 202 has a sealed structure, and a gas with a pressure higher than the atmospheric pressure of the surrounding environment in which the air conditioner 1 is installed is sealed in the space 20c. The other configurations are the same as those in embodiment 1, so a description thereof will be omitted here.

[0095] As shown in FIG. 13, in the fifth embodiment, the space 20c between the high pressure release valve 204 and the partition valve 202 in the flow path 20a is made to have a sealed structure. In addition, when the pressure release valve 20 is manufactured, the gas 205 is sealed in the space 20c at a preset pressure. Therefore, the pressure of the gas 205 is higher than the atmospheric pressure of the surrounding environment in which the air conditioner 1 is installed. The gas 205 is, for example, an inert gas. This can reduce the average stress of the partition valve 202 of the pressure release valve 20 and increase the fatigue strength of the partition valve 202.

[0096] The inert gas used as gas 205 is a gas made of a material that does not cause a chemical reaction such as corrosion even when it comes into contact with pressure release valve 20 .

[0097] As described above, in the fifth embodiment as well, similar to the first embodiment, the outdoor unit 1a of the air conditioner 1 is provided with the pressure release valve 20, and therefore the same effects as those of the first embodiment can be obtained.

[0098] In the fifth embodiment, the space 20c between the high pressure release valve 204 and the partition valve 202 in the flow path 20a is sealed to seal in the gas 205. This reduces the average stress of the partition valve 202 of the pressure release valve 20, and increases the fatigue strength of the partition valve 202.

[0099] Embodiment 6 Fig. 14 is a perspective view showing the configuration of a pressure release valve 20 provided in an air conditioner 1 according to embodiment 6. In Fig. 14, for the sake of explanation, some of the configuration is shown in transparent broken lines. Fig. 15 is a cross-sectional view showing the configuration of a pressure release valve 20 provided in an air conditioner 1 according to embodiment 6. The difference between embodiment 6 and embodiment 1 is that in embodiment 6, a notch 204b is provided in an upper surface 204a of a high pressure release valve 204. As the other configurations are the same as those in embodiment 1, explanations thereof will be omitted here.

[0100] 14 and 15, in the sixth embodiment, a notch 204b is provided in the upper surface 204a of the high pressure release valve 204. The notch 204b is formed in the center of the upper surface 204a of the high pressure release valve 204. The width of the notch 204b is, for example, about 0.1 mm. The depth of the notch 204b is, for example, about 1 / 10 of the plate thickness D1 of the upper surface 204a of the high pressure release valve 204.

[0101] 14, the shape of the notch 204b is an X-shape in plan view. That is, two linear notches are formed and they intersect with each other. The two linear notches may be perpendicular to each other or may intersect at a certain angle.

[0102] In the entire upper surface 204a of the high pressure release valve 204, the notch 204b has a thinner plate thickness than other parts of the upper surface 204a of the high pressure release valve 204, and therefore the static pressure resistance strength is weaker. Therefore, when the high pressure release valve 204 opens (i.e., breaks), the high pressure release valve 204 breaks from the notch 204b. In this way, by providing the notch 204b in the high pressure release valve 204, the strength and opening shape of the high pressure release valve 204 when it opens (i.e., breaks) can be controlled. Therefore, it is possible to prevent the compressor 2 from breaking due to the time it takes for the high pressure release valve 204 to open. In addition, since the opening of the high pressure release valve 204 starts from the notch 204b, the opening shape and opening area required for releasing the high pressure gas can be reliably secured.

[0103] Instead of providing the notch 204b in the high pressure release valve 204, a thickness distribution is configured on the upper surface 204a of the high pressure release valve 204 during drawing. Specifically, the thickness D1 of the upper surface 204a of the high pressure release valve 204 is not uniform, but the thickness of a portion of the upper surface 204a is made thinner than the other portions. The portion with the thinner thickness has a weaker static pressure resistance strength than the other portions of the upper surface 204a of the high pressure release valve 204. In this way, a thickness distribution is configured such that the thickness of a portion of the upper surface 204a is thinner than the other portions, and the same effect as that of the notch 204b may be achieved by this thickness distribution.

[0104] As described above, in the sixth embodiment as well, similar to the first embodiment, the outdoor unit 1a of the air conditioner 1 is provided with the pressure release valve 20, and therefore the same effects as those of the first embodiment can be obtained.

[0105] Furthermore, in the sixth embodiment, the plate thickness of the upper surface 204a of the high pressure release valve 204 is partially thinned by providing the notch 204b in the upper surface 204a of the high pressure release valve 204. Therefore, when the high pressure release valve 204 opens (i.e., breaks), the high pressure release valve 204 breaks from the portion of the notch 204b. In this way, by providing the notch 204b in the high pressure release valve 204, the strength and opening shape of the high pressure release valve 204 when it is open can be controlled, so that a release flow path for the high pressure gas can be reliably secured.

[0106] Embodiment 7 Fig. 16 is a cross-sectional view showing the configuration of a pressure release valve 20 provided in an air conditioner 1 according to embodiment 7. The difference between embodiment 7 and embodiment 1 is that embodiment 7 is provided with a strain measuring unit 206 that measures strain on an upper surface 204a of the high pressure release valve 204. The other configuration is the same as embodiment 1, so a description thereof will be omitted here.

[0107] The bulkhead valve 202 is destroyed before the high pressure release valve 204 due to metal fatigue or the like. If the bulkhead valve 202 is destroyed while the compressor 2 can continue to operate, the pressure applied to the deformation amount of the high pressure release valve 204 increases, and the strain of the high pressure release valve 204 increases. Therefore, in the seventh embodiment, as shown in FIG. 16, in order to measure the strain of the upper surface 204a of the high pressure release valve 204, a strain measuring unit 206 is provided in the high pressure release valve 204. It is preferable that the strain measuring unit 206 is installed on the upper surface 204a of the high pressure release valve 204. In addition, the strain measuring unit 206 is composed of, for example, a strain gauge. The strain measuring unit 206 is installed on the upper surface 204a of the high pressure release valve 204 when the air conditioner 1 is installed, and constantly measures the strain of the high pressure release valve 204. The measurement results are stored in the memory of the control unit 13 as time series data. The control unit 13 determines that the partition valve 202 is destroyed when the measured strain of the high pressure release valve 204 exceeds a preset threshold value Th2 based on the measurement result of the strain measuring unit 206. Alternatively, the control unit 13 calculates the increase rate of the strain of the high pressure release valve 204 in a certain fixed period based on the time series data, and determines that the partition valve 202 is destroyed when the increase rate exceeds a preset threshold value Th3.

[0108] In this way, by measuring the strain of the high pressure release valve 204, it is possible to determine whether or not the partition valve 202 installed in the pressure release valve 20 is broken. If the partition valve 202 is broken, it is assumed that the strength of the housing 22 of the compressor 2 is also deteriorated. Therefore, when the control unit 13 determines that the cumulative operation time of the air conditioner 1 exceeds a preset threshold value Th4 and that the partition valve 202 is broken, it presents a message to the user urging replacement of the compressor 2. In addition, when the control unit 13 determines that the cumulative operation time of the air conditioner 1 exceeds a preset threshold value Th4 and that the partition valve 202 is broken, it may stop the operation of the air conditioner 1. Note that the control unit 13 may both present a message and stop the operation of the air conditioner 1, or may perform only one of them.

[0109] In this way, the lifespan of the casing 22 of the compressor 2 can be predicted from the presence or absence of damage to the partition valve 202. For this reason, in the seventh embodiment, a strain measuring unit 206 is provided to determine the presence or absence of damage to the partition valve 202 based on the measurement results. Then, if the partition valve 202 is damaged and the accumulated operating time of the air conditioner 1 exceeds threshold value Th4, the user can be notified that the lifespan of the compressor 2 is approaching. This makes it possible to urge the user to replace the compressor 2 or the air conditioner 1 before the compressor 2 is damaged.

[0110] In the seventh embodiment, when the notch 204b shown in the sixth embodiment is provided on the upper surface 204a of the high pressure release valve 204, the strain measuring unit 206 is installed to avoid the portion of the notch 204b. In that case, there is a possibility that a deviation occurs in the strain measurement result compared to the case where the strain measuring unit 206 is provided in the center part of the upper surface 204a of the high pressure release valve 204. Therefore, the deviation may be obtained in advance by an experiment or the like, and the control unit 13 may compensate the strain measurement result based on the deviation.

[0111] As described above, in the seventh embodiment, similarly to the first embodiment, the outdoor unit 1a of the air conditioner 1 is provided with the pressure release valve 20, and therefore the same effects as those of the first embodiment can be obtained.

[0112] Moreover, in the seventh embodiment, the high pressure release valve 204 is provided with a strain measuring unit 206. The control unit 13 can determine whether or not the partition valve 202 is broken based on the measurement results of the strain measuring unit 206. Furthermore, the control unit 13 can predict the lifespan of the casing 22 of the compressor 2 from whether or not the partition valve 202 is broken. This makes it possible to urge the user to replace the compressor 2 or the air conditioner 1 before the compressor 2 is broken. [Explanation of symbols]

[0113] 1 air conditioner, 1a outdoor unit, 1b indoor unit, 2 compressor, 3 muffler, 4 four-way switching valve, 5 outdoor heat exchanger, 6 refrigerant pressure reducing device, 7 liquid side shutoff valve, 8 indoor heat exchanger, 9 gas side shutoff valve, 10 refrigerant piping, 11 outdoor blower, 11a fan motor, 11b blade portion, 12 indoor blower, 12a fan motor, 12b blade portion, 13 control portion, 14 control portion, 20 pressure release valve, 20a flow path portion, 20b valve body portion, 20c space, 21 discharge pipe, 22 housing, 23 top surface, 24 side surface, 25 bottom surface, 30 solid line, 31 dashed line, 32 dashed line, 33 solid line, 40 black circle mark, 41 black triangle mark, 42 ​​black star mark, 201 Pipe for partition valve, 201a lower end, 201b first portion, 201c upper end, 201d second portion, 201e stepped portion, 201f convex portion, 202 partition valve, 202a upper surface, 202b side portion, 202c lower end, 203 pipe for high pressure release valve, 203a lower end, 203aa portion, 203b first portion, 203c upper end, 203d second portion, 203e stepped portion, 203f convex portion, 203g portion, 204 high pressure release valve, 204a upper surface, 204b notch portion, 204c lower end, 204d side portion, 205 gas, 206 strain measurement portion.

Claims

1. a refrigeration cycle including a refrigerant circuit in which a compressor, an outdoor heat exchanger, a refrigerant pressure reducing device, and an indoor heat exchanger are connected by refrigerant piping; a pressure relief valve that is provided in the refrigerant circuit and opens when the pressure (P) inside the compressor reaches a preset opening pressure (Pp) to release the compressed gas inside the compressor to the outside; Equipped with When a flow direction of the compressed gas when the compressed gas is released to the outside is defined as a first direction, The pressure relief valve is a partition valve disposed upstream in the first direction, in contact with an internal space of the compressor, and subjected to fluctuations in pressure (P) inside the compressor during normal operation of the compressor; a high pressure release valve that is disposed downstream of the partition valve in the first direction and opens when the pressure (P) inside the compressor reaches a preset opening pressure (Pp); having The high pressure release valve and the partition valve are arranged in series along the first direction, and have different static pressure resistance strengths or fatigue strengths due to pressure fluctuations. Air conditioner.

2. The diaphragm valve is a pressure relief valve disposed upstream of the high pressure relief valve in the first direction, the pressure relief valve being subjected to fluctuations in the pressure (P) inside the compressor during normal operation when the pressure (P) inside the compressor is equal to or lower than a design pressure (Pcomp) of the compressor; The high pressure relief valve is The opening pressure (Pp) is set to a value that is greater than the guaranteed pressure (Pmax) of the compressor legally defined based on the design pressure (Pcomp) of the compressor and less than the damage pressure (P'max) at which the compressor is damaged. The air conditioner according to claim 1.

3. A refrigeration cycle comprising a refrigerant circuit in which a compressor, an outdoor heat exchanger, a refrigerant pressure reducing device, and an indoor heat exchanger are connected by refrigerant piping; a pressure relief valve that is provided in the refrigerant circuit and opens when the pressure (P) inside the compressor reaches a preset opening pressure (Pp) to release the compressed gas inside the compressor to the outside; Equipped with When a flow direction of the compressed gas when the compressed gas is released to the outside is defined as a first direction, The pressure relief valve is a partition valve disposed upstream in the first direction, in contact with an internal space of the compressor, and subjected to fluctuations in pressure (P) inside the compressor during normal operation of the compressor; a high pressure release valve that is disposed downstream of the partition valve in the first direction and opens when the pressure (P) inside the compressor reaches a preset opening pressure (Pp); having the high pressure relief valve and the partition valve are arranged in series along the first direction; The high pressure release valve and the partition valve have different static pressure resistance and fatigue strength due to pressure fluctuation. Air conditioner.

4. The high pressure relief valve has a static pressure resistance greater than that of the bulkhead valve, The diaphragm valve has a higher fatigue strength than the high pressure relief valve. The air conditioner according to claim 3.

5. the high pressure release valve is a valve having one end on a downstream side in the first direction that is closed and one end on an upstream side in the first direction that is open, a closing surface constituting the closed downstream end has a planar shape, The partition valve is a valve having one end on a downstream side in the first direction that is closed and one end on an upstream side in the first direction that is open, and a closing surface constituting the closed downstream end has a curved shape. The air conditioner according to any one of claims 1 to 4.

6. a cutout is provided on the closing surface of the high pressure relief valve; The air conditioner according to claim 5.

7. A strain measuring unit that measures a strain of the blocking surface is provided on the blocking surface of the high pressure release valve.

7. The air conditioner according to claim 5 or 6.

8. The partition valve is disposed inside a cylindrical partition valve pipe that supports the partition valve, The partition valve is joined to an inner wall of the partition valve pipe, The high pressure relief valve is disposed inside a cylindrical high pressure relief valve pipe that supports the high pressure relief valve, The high pressure relief valve is joined to the inner wall of the high pressure relief valve pipe, The high pressure release valve pipe and the partition valve pipe are arranged in series along the first direction so that their axial directions coincide with each other, and are joined to each other. An air conditioner according to any one of claims 1 to 7.

9. a positioning portion for performing axial and radial positioning is provided on a joining surface when the partition valve pipe and the high pressure release valve pipe are joined, The positioning portion is a male portion provided on either one of a joint surface of the partition wall valve pipe side and a joint surface of the high pressure release valve pipe side; a female portion provided on the other of the joint surface on the partition valve pipe side and the joint surface on the high pressure release valve pipe side, the female portion having a complementary shape to the male portion; It is composed of The air conditioner according to claim 8.

10. At least a portion of the downstream end of the partition valve pipe is inserted and joined to the upstream end of the high pressure release valve pipe. The air conditioner according to claim 8.

11. In a flow path portion constituted by the high pressure release valve pipe and the partition valve pipe, a space formed between the high pressure release valve and the partition valve is sealed. The air conditioner according to any one of claims 8 to 10.

12. The space formed between the high pressure release valve and the partition valve is filled with gas at a pressure higher than the atmospheric pressure of the surrounding environment in which the air conditioner is installed. The air conditioner according to claim 11.

13. A pressure relief valve that is provided in a pressure vessel and opens when the pressure (P) inside the pressure vessel reaches a preset opening pressure (Pp) to release compressed gas inside the pressure vessel to the outside, When a flow direction of the compressed gas when the compressed gas is released to the outside is defined as a first direction, The pressure relief valve is a partition valve disposed upstream in the first direction, in contact with an internal space of the pressure vessel, and subjected to fluctuations in pressure (P) inside the pressure vessel; a high pressure release valve that is disposed downstream of the partition valve in the first direction and opens when the pressure (P) inside the pressure vessel reaches a preset opening pressure (Pp); having The high pressure release valve and the partition valve are arranged in series along the first direction, and have different static pressure resistance strengths or fatigue strengths due to pressure fluctuations. Pressure relief valve.

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