Oil tank used in centrifugal refrigerator and centrifugal refrigerator

Abstract

The oil tank used in a centrifugal refrigerator and the centrifugal refrigerator provided by the present invention prevent the jet of a mixed fluid of refrigerant and lubricating oil from colliding with the lubricating oil from the compressor, thereby increasing the recovery rate of the lubricating oil. The oil tank (30) comprises: a storage container (51) for storing the lubricating oil inside, an oil inlet (54) for returning the lubricating oil supplied to the sliding part to the storage container (51), a mixed fluid inlet (56) for introducing a mixed fluid of refrigerant liquid and lubricating oil into the storage container (51), a refrigerant outlet (58) for releasing the refrigerant vapor in the storage container (51), and a structure (60) for preventing the lubricating oil flowing into the storage container (51) from the oil inlet (54) from colliding with the mixed fluid flowing into the storage container (51) from the mixed fluid inlet (56).

Description

Technical Field

[0001] The present invention relates to an oil tank used in a centrifugal refrigerator, and more particularly to an oil tank for storing lubricating oil supplied to sliding parts such as bearings and gears of a compressor. The present invention also relates to a centrifugal refrigerator equipped with the oil tank. Background Art

[0002] In centrifugal chillers, lubricating oil is used to lubricate the sliding parts of the compressor, such as bearings and gears. The oil is pumped from the oil tank to the sliding parts by an oil pump. The lubricating oil supplied to the sliding parts returns to the oil tank. Meanwhile, some of the lubricating oil in the compressor leaks into the refrigerant flow path and mixes with the refrigerant vapor. The lubricating oil, along with the refrigerant vapor, is discharged from the compressor and enters the condenser. Furthermore, as the refrigerant circulates, the lubricating oil accumulates in the evaporator. Therefore, to maintain stable operation of the centrifugal chiller, the mixture of lubricating oil and refrigerant liquid is recovered from the evaporator and returned to the oil tank.

[0003] The oil tank is connected to the evaporator through a pressure equalizing pipe, so that the internal pressure of the oil tank is roughly the same as that of the evaporator. Therefore, when the mixed fluid of lubricating oil and refrigerant liquid recovered by the ejector driven by the refrigerant vapor discharged from the compressor and the refrigerant vapor from the condenser flows into the oil tank, a part of the refrigerant liquid evaporates (flash evaporates) instantly and becomes refrigerant vapor. The flow rate of the refrigerant vapor containing lubricating oil increases significantly, forming a jet of mixed fluid in the oil tank. In particular, when the temperature of the cooled fluid flowing in the evaporator is low and the internal pressure of the evaporator is low, the increase in flow rate caused by the flash evaporation of the refrigerant in the oil tank is large. On the other hand, the lubricating oil returning to the oil tank from the sliding part of the compressor has a smaller refrigerant content, so the increase in flow rate caused by the evaporation of the refrigerant is small.

[0004] The refrigerant that flows into the oil tank evaporates and is then transported to the evaporator (or compressor suction pipe) via the refrigerant vapor piping (pressure equalizing pipe) connected to the refrigerant outlet of the oil tank. The lubricating oil separated from the refrigerant is stored in the oil tank. The lubricating oil in the oil tank is supplied to the sliding parts of the compressor via the oil supply pipe by an oil pump. The lubricating oil is then recovered and returned to the oil tank for reuse in lubricating the sliding parts of the compressor.

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2014-190627

[0006] However, the jet of mixed fluid formed in the oil tank collides with the lubricating oil from the compressor, causing the lubricating oil to form a mist. This misted lubricating oil is carried by the refrigerant vapor and discharged from the oil tank, making it impossible to maintain the oil level in the tank. To avoid this, the size of the oil tank needs to be increased. Furthermore, the jet of refrigerant vapor collides with the oil surface in the oil tank, causing the lubricating oil to scatter. This scattered lubricating oil is carried by the refrigerant vapor and discharged from the oil tank. This further destabilizes the oil surface, causing cavitation in the oil pump, which also affects the supply of lubricating oil. Summary of the Invention

[0007] Therefore, the present invention provides an oil tank capable of preventing a jet of a mixed fluid of refrigerant and lubricating oil from colliding with the lubricating oil from a compressor, thereby increasing the recovery rate of the lubricating oil.

[0008] In one embodiment, an oil tank is provided for storing lubricating oil for lubricating the sliding parts of a compressor used in a centrifugal refrigerator, comprising: a storage container for storing the lubricating oil therein; an oil inlet for returning the lubricating oil supplied to the sliding parts to the storage container; a mixed fluid inlet for introducing a mixed fluid of refrigerant liquid and lubricating oil into the storage container; a refrigerant outlet for releasing refrigerant vapor in the storage container; and a structure for preventing the lubricating oil flowing into the storage container from the oil inlet from colliding with the mixed fluid flowing into the storage container from the mixed fluid inlet.

[0009] According to the present invention, collision between the lubricating oil and the mixed fluid in the storage container is prevented. This prevents the lubricating oil from atomizing due to collision, and prevents the atomized lubricating oil from flowing out of the oil tank along with the refrigerant vapor. As a result, the lubricating oil recovery rate is improved. Furthermore, by preventing lubricating oil atomization, the size of the oil tank can be reduced.

[0010] In one embodiment, the structure is a baffle disposed in the storage container, and at least a portion of the baffle is disposed between the oil inlet and the mixed fluid inlet.

[0011] According to the present invention, the baffle plate prevents the lubricating oil in the storage container from colliding with the mixed fluid.

[0012] In one embodiment, the baffle includes: a first wall arranged approximately horizontally; and a second wall extending upward from the first wall; the mixed fluid inlet is arranged so that the mixed fluid flows toward the upper surface of the first wall; and the second wall is located between the refrigerant outlet and the mixed fluid inlet.

[0013] In one embodiment, the oil inlet is arranged toward the lower surface of the first wall.

[0014] In one embodiment, the baffle further includes a third wall extending upward from the first wall, the mixed fluid inlet is located between the second wall and the third wall, the third wall is located between the mixed fluid inlet and the oil inlet, and the oil inlet is arranged toward the outer surface of the third wall.

[0015] When the mixed fluid flows into the storage container, the refrigerant liquid contained in the mixed fluid evaporates (flash evaporates) instantly to form a high-speed mixed fluid. According to the present invention, the mixed fluid with a higher flow rate collides with the first wall instead of colliding with the oil surface in the storage container. Therefore, the scattering of the lubricating oil is suppressed, the oil surface can be stabilized, and the lubricating oil can be stably supplied to the sliding part of the compressor. In addition, according to the present invention, when the mixed fluid collides with the first wall, the lubricating oil contained in the mixed fluid adheres to the first wall, and the lubricating oil is separated from the refrigerant. In addition, when the mixed fluid collides with the first wall, its direction of travel changes and collides with the inner surface of the storage container. The lubricating oil contained in the mixed fluid adheres to the inner surface of the storage container, and the lubricating oil is separated from the refrigerant. In this way, the lubricating oil contained in the mixed fluid is separated from the refrigerant in two stages, thereby improving the recovery rate of the lubricating oil.

[0016] In one embodiment, the mixed fluid inlet is arranged on one side wall of the storage container, and the oil inlet is arranged on the opposite side wall of the storage container.

[0017] According to the present invention, the mixed fluid inlet is separated from the oil inlet, allowing the lubricating oil to be introduced into an area with a lower refrigerant vapor velocity. This reduces the chance of the lubricating oil being agitated by the refrigerant vapor, preventing atomization of the lubricating oil. Consequently, the lubricating oil recovery rate is improved.

[0018] In one embodiment, the mixed fluid inlet and the oil inlet face the refrigerant outlet, and the mixed fluid inlet is located between the oil inlet and the refrigerant outlet.

[0019] According to the present invention, the mixed fluid inlet is located downstream of the refrigerant vapor flow direction within the storage container, while the oil inlet is located upstream. This configuration directs the lubricating oil into an area where the refrigerant vapor flow velocity is low. This reduces the chance of the lubricating oil being agitated by the refrigerant vapor, preventing atomization of the lubricating oil. Consequently, the recovery rate of the lubricating oil is improved.

[0020] In one embodiment, the baffle includes: a first wall arranged approximately horizontally, and a second wall extending upward from the first wall, the mixed fluid inlet is located above the first wall and is arranged so that the mixed fluid flows toward the second wall, and the second wall is located between the refrigerant outlet and the mixed fluid inlet.

[0021] When the mixed fluid flows into the storage container, the refrigerant liquid contained in the mixed fluid evaporates (flash evaporates) instantly to form a high-speed mixed fluid. According to the present invention, the mixed fluid with a higher flow rate collides with the second wall, and the first wall prevents the mixed fluid from colliding with the oil surface in the storage container. Therefore, the scattering of the lubricating oil is suppressed, the oil surface can be stabilized, and the lubricating oil can be stably supplied to the sliding part of the compressor. In addition, according to the present invention, when the mixed fluid collides with the second wall, the lubricating oil contained in the mixed fluid adheres to the second wall, and the lubricating oil is separated from the refrigerant. In addition, when the mixed fluid collides with the second wall, its direction of travel changes, and it collides with the inner surface of the storage container. The lubricating oil contained in the mixed fluid adheres to the inner surface of the storage container, and the lubricating oil is separated from the refrigerant. In this way, the lubricating oil contained in the mixed fluid is separated from the refrigerant in two stages, thereby improving the recovery rate of the lubricating oil.

[0022] In one embodiment, the oil inlet is arranged below the first wall.

[0023] According to the present invention, the first wall prevents the lubricating oil from colliding with the mixed fluid having a relatively high flow rate.

[0024] In one embodiment, the oil tank further includes a defogger disposed in a pipe constituting the refrigerant outlet.

[0025] According to the present invention, the demister captures mist-like lubricating oil contained in the refrigerant vapor and can separate the lubricating oil from the refrigerant vapor. As a result, the recovery rate of the lubricating oil can be improved.

[0026] In one embodiment, a centrifugal refrigerator is provided, comprising: an evaporator that evaporates a refrigerant liquid to generate a refrigerant vapor; a compressor that compresses the refrigerant vapor; a condenser that condenses the compressed refrigerant vapor to generate the refrigerant liquid; and an oil tank for storing lubricating oil for lubricating a sliding portion of the compressor, wherein the oil tank is the oil tank according to any one of claims 1 to 10.

[0027] The mixed fluid inlet of the oil tank is connected to a mixed fluid recovery line extending from the evaporator.

[0028] The mixed fluid inlet of the oil tank is connected to an oil recovery line extending from an oil reservoir of the compressor.

[0029] According to the present invention, collision between the lubricating oil and the mixed fluid in the storage container is prevented. This prevents the lubricating oil from atomizing due to collision, preventing the atomized lubricating oil from flowing out of the oil tank along with the refrigerant vapor. As a result, the lubricating oil recovery rate is improved. Furthermore, by preventing lubricating oil atomization, the size of the oil tank can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram showing one embodiment of a centrifugal refrigerator.

[0031] Figure 2 It is a cross-sectional view showing one embodiment of the oil tank.

[0032] Figure 3 yes Figure 2 The AA line cross-sectional view is shown.

[0033] Figure 4 It is a three-dimensional diagram of the baffle.

[0034] Figure 5 It is a cross-sectional view showing another embodiment of the oil tank.

[0035] Figure 6 It is a cross-sectional view showing still another embodiment of the oil tank.

[0036] Figure 7 It is a cross-sectional view showing still another embodiment of the oil tank.

[0037] Figure 8 yes Figure 7 The BB line cross-sectional view is shown.

[0038] Figure 9 It is a cross-sectional view showing still another embodiment of the oil tank.

[0039] Figure 10 It is a cross-sectional view showing still another embodiment of the oil tank.

[0040] Figure 11 It is a cross-sectional view showing still another embodiment of the oil tank.

[0041] Figure 12 It is a schematic diagram showing another embodiment of a centrifugal refrigerator.

[0042] Explanation of Reference Numerals: 1… compressor; 2… evaporator; 3… condenser; 4A, 4B, 4C, 4D, 4E… refrigerant piping; 9… economizer; 11… first-stage impeller; 12… second-stage impeller; 13… motor; 16… guide vane; 17… intermediate suction port; 18… gear; 19… bearing; 20… gearbox; 21, 22… expansion valve; 23… bearing; 30… oil tank; 32… oil pump; 35… oil supply Feed line; 36…oil return line; 38…mixed fluid recovery line; 40, 73…ejector; 43, 75…working fluid line; 47…refrigerant return line; 51…storage container; 54…oil inlet; 56…mixed fluid inlet; 58…refrigerant outlet; 60…baffle; 60a…first wall; 60b…second wall; 60c…third wall; 65…demister; 70…oil recovery line; 72…oil storage section. DETAILED DESCRIPTION

[0043] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0044] Figure 1 Schematic diagram showing one embodiment of a centrifugal refrigerator. Figure 1 As shown, the centrifugal chiller includes an evaporator 2 that evaporates a refrigerant liquid to generate refrigerant vapor; a compressor 1 that compresses the refrigerant vapor; and a condenser 3 that condenses the compressed refrigerant vapor to generate refrigerant liquid. The suction port of compressor 1 is connected to evaporator 2 via refrigerant piping 4A. The discharge port of compressor 1 is connected to condenser 3 via refrigerant piping 4B.

[0045] The centrifugal chiller further includes an economizer 9 disposed between the condenser 3 and the evaporator 2. The condenser 3 is connected to the economizer 9 via a refrigerant pipe 4C, and the economizer 9 is connected to the evaporator 2 via a refrigerant pipe 4D. Furthermore, the economizer 9 is connected to the compressor 1 via a refrigerant pipe 4E. The economizer 9 is an intercooler disposed between the condenser 3 and the evaporator 2. An expansion valve 21 is attached to the refrigerant pipe 4C extending from the condenser 3 to the economizer 9, and an expansion valve 22 is attached to the refrigerant pipe 4D extending from the economizer 9 to the evaporator 2. The expansion valves 21 and 22 are configured so that their openings can be adjusted, and are, for example, motorized valves with variable openings.

[0046] The evaporator 2 takes heat from the cooled fluid (e.g., cold water), causing the refrigerant liquid to evaporate and exert a cooling effect. The compressor 1 compresses the refrigerant vapor evaporated in the evaporator 2 to generate high-pressure refrigerant vapor. The condenser 3 uses a cooling fluid (e.g., cooling water) to cool the high-pressure refrigerant vapor and condense it, thereby generating refrigerant liquid. The refrigerant liquid passes through the expansion valve 21, thereby being decompressed. The refrigerant vapor present in the decompressed refrigerant liquid is separated by the economizer 9 and transported to the intermediate suction port 17 provided between the first-stage impeller 11 and the second-stage impeller 12 of the compressor 1. The refrigerant liquid after passing through the economizer 9 is decompressed by passing through the expansion valve 22 and is then transported to the evaporator 2 through the refrigerant piping 4D. In this way, the centrifugal refrigeration mechanism becomes a closed system in which the refrigerant is sealed. There are also cases where the economizer 9 is omitted.

[0047] In this embodiment, the compressor 1 is a multi-stage centrifugal compressor 1. More specifically, the compressor 1 is a two-stage centrifugal compressor 1, comprising a first-stage impeller 11, a second-stage impeller 12, and a motor 13 for rotating the impellers 11 and 12. The compressor 1 further comprises a gear 18 connecting the impellers 11 and 12 to the motor 13, a bearing 19 rotatably supporting a rotating shaft to which the impellers 11 and 12 are fixed, a bearing 23 supporting the shaft of the motor 13, and a gear box 20 housing a sliding portion including at least the gear 18 and the bearing 19.

[0048] The compressor 1's suction port is equipped with guide vanes 16 to adjust the flow rate of refrigerant vapor entering the impellers 11 and 12. These vanes 16 are located on the suction side of the first-stage impeller 11. The guide vanes 16 are arranged radially, and each vane 16 rotates synchronously with the others about its own axis by a predetermined angle, thereby changing the opening of the guide vanes 16. The refrigerant vapor delivered from the evaporator 2 passes through the guide vanes 16 and is subsequently pressurized by the rotating impellers 11 and 12. The pressurized refrigerant vapor is then transported to the condenser 3 via the refrigerant pipe 4B.

[0049] The centrifugal chiller includes an oil tank 30 that stores lubricating oil for lubricating the sliding parts of the compressor 1, and an oil pump 32 that delivers the lubricating oil from the oil tank 30 to the compressor 1. The oil pump 32 is connected to the oil tank 30. The oil tank 30 is connected to the compressor 1 via an oil supply line 35 and an oil return line 36. More specifically, one end of the oil supply line 35 is connected to the gear box 20, and the other end of the oil supply line 35 is connected to the oil pump 32. One end of the oil return line 36 is connected to the lower portion of the gear box 20, and the other end of the oil return line 36 is connected to the oil tank 30.

[0050] When the oil pump 32 operates, lubricating oil is supplied from the oil tank 30 through the oil supply line 35 into the gearbox 20. The lubricating oil is supplied to the sliding parts of the gearbox 20, such as the gear 18 and bearings 19 and 23, to lubricate these sliding parts. The lubricating oil, having lubricated the sliding parts, falls from the sliding parts due to its own weight and accumulates in the gearbox 20. The lubricating oil in the gearbox 20 flows into the oil tank 30 through the oil return line 36. The lubricating oil in the oil tank 30 is then transferred by the oil pump 32 through the oil supply line 35 to the gearbox 20, where it is again used to lubricate the sliding parts. In this way, the lubricating oil circulates between the oil tank 30 and the gearbox 20 through the oil supply line 35 and the oil return line 36.

[0051] A portion of the lubricating oil in the compressor 1 leaks into the refrigerant flow path and mixes with the refrigerant vapor. The lubricating oil is discharged from the compressor 1 together with the refrigerant vapor and enters the condenser 3. Furthermore, through the refrigerant circulation, the lubricating oil accumulates in the evaporator 2. The lubricating oil in the evaporator 2 mixes with the refrigerant liquid to form a mixed fluid of the lubricating oil and the refrigerant liquid. In order to ensure continued stable operation of the centrifugal chiller, the mixed fluid of the lubricating oil and the refrigerant liquid is recovered from the evaporator 2 to the oil tank 30 through the mixed fluid recovery line 38. One end of the mixed fluid recovery line 38 is connected to the evaporator 2, and the other end of the mixed fluid recovery line 38 is connected to the oil tank 30.

[0052] A mixed fluid of lubricating oil and refrigerant liquid is recovered from a place where there is a relatively large amount of lubricating oil in the evaporator 2. An ejector 40 that uses refrigerant vapor as a working fluid is used as a driving source for recovering the mixed fluid. The mixed fluid recovery line 38 extends to the oil tank 30 via the ejector 40. The working fluid line 43 branches from the refrigerant piping 4B and is connected to the ejector 40. A portion of the refrigerant vapor flowing from the compressor 1 to the condenser 3 is injected into the ejector 40 from the refrigerant piping 4B through the working fluid line 43 and acts as a working fluid for the ejector 40. The ejector 40 draws in a mixed fluid of lubricating oil and refrigerant liquid from the evaporator 2 and transfers the mixed fluid to the oil tank 30.

[0053] The refrigerant contained in the mixed fluid separates from the lubricating oil in the form of refrigerant vapor within the oil tank 30. While the lubricating oil remains within the oil tank 30, the refrigerant vapor returns to the evaporator 2 via the refrigerant return line 47. One end of the refrigerant return line 47 is connected to the oil tank 30, and the other end is connected to the evaporator 2.

[0054] Figure 2 is a cross-sectional view showing one embodiment of the oil tank 30. Figure 3 yes Figure 2 The oil tank 30 is provided with a storage container 51 for storing lubricating oil therein, an oil inlet 54 for returning lubricating oil supplied to the sliding part of the compressor 1 to the storage container 51, a mixed fluid inlet 56 for introducing a mixed fluid of refrigerant liquid and lubricating oil into the storage container 51, and a refrigerant outlet 58 for releasing refrigerant vapor in the storage container 51. The oil inlet 54 is connected to Figure 1 The oil return line 36 is shown. The mixed fluid inlet 56 is connected to the Figure 1 The mixed fluid recovery line 38 is shown. The refrigerant outlet 58 is connected to Figure 1 Refrigerant return line 47 is shown.

[0055] The oil tank 30 includes a baffle 60, which serves as a structure to prevent collision between the lubricating oil flowing into the storage container 51 from the oil inlet 54 and the mixed fluid flowing into the storage container 51 from the mixed fluid inlet 56. The baffle 60 is disposed within the storage container 51. At least a portion of the baffle 60 is disposed between the oil inlet 54 and the mixed fluid inlet 56. The baffle 60 is connected to the upper wall 51a of the storage container 51, while the oil inlet 54 is fixed to the side wall 51b of the storage container 51. The mixed fluid inlet 56 is fixed to the upper wall 51a of the storage container 51 and disposed above the baffle 60. The oil pump 32 is fixed to the side wall 51b. In one embodiment, the oil pump 32 may also be fixed to the side wall 51c, the opposite side wall of the storage container 51.

[0056] Figure 4 This is a perspective view of the baffle 60. The baffle 60 includes a first wall 60a arranged substantially horizontally, and a second wall 60b and a third wall 60c extending upward from the first wall 60a. The second wall 60b and the third wall 60c are arranged parallel to each other. The mixed fluid inlet 56 is located above the first wall 60a and is configured so that the mixed fluid flows toward the upper surface of the first wall 60a. The mixed fluid inlet 56 is located between the second wall 60b and the third wall 60c. The third wall 60c is located between the mixed fluid inlet 56 and the oil inlet 54. The oil inlet 54 is arranged toward the outer surface of the third wall 60c.

[0057] like Figure 2 As shown, the upper ends of the second wall 60b and the third wall 60c are connected to the upper wall 51a of the storage container 51, and the lower ends of the second wall 60b and the third wall 60c are connected to the edges of the first wall 60a on both sides. The second wall 60b is located between the refrigerant outlet 58 and the mixed fluid inlet 56. A gap is formed between the third wall 60c and the side wall 51b of the storage container 51.

[0058] like Figure 1 As shown, the oil tank 30 is connected to the evaporator 2 via a refrigerant return line (pressure equalizing pipe) 47, so the internal pressure of the oil tank 30 is approximately the same as the pressure of the evaporator 2. Lubricating oil returned from the gearbox 20 of the compressor 1 flows into the storage container 51 through the oil inlet 54. This lubricating oil contains almost no refrigerant, so when the lubricating oil flows into the storage container 51, only a small amount of refrigerant liquid evaporates, and no jet flow is actually formed.

[0059] On the other hand, when the mixed fluid flows into the storage container 51 from the mixed fluid inlet 56, the refrigerant liquid contained in the mixed fluid instantly evaporates (flashes), forming a high-speed mixed fluid. According to this embodiment, the third wall 60c of the baffle 60 is arranged between the oil inlet 54 and the mixed fluid inlet 56. Therefore, the baffle 60 prevents the lubricating oil in the storage container 51 from colliding with the mixed fluid. Therefore, the atomization of the lubricating oil caused by the collision can be avoided, thereby preventing the atomized lubricating oil from flowing out of the oil tank 30 along with the refrigerant vapor. As a result, the recovery rate of the lubricating oil is improved. Since the atomization of the lubricating oil can be avoided, the size of the oil tank 30 can be reduced.

[0060] Furthermore, according to this embodiment, the mixed fluid inlet 56 is disposed toward the first wall 60a. Therefore, the mixed fluid having a relatively high flow velocity collides with the first wall 60a rather than with the oil surface in the storage container 51. Therefore, scattering of the lubricating oil is suppressed, the oil surface is stabilized, and the lubricating oil can be stably supplied to the sliding parts of the compressor 1.

[0061] In addition, if Figure 3 As shown, when the mixed fluid collides with the first wall 60a, the lubricating oil contained in the mixed fluid adheres to the first wall 60a, separating the lubricating oil from the refrigerant. The lubricating oil flows along the first wall 60a and falls into the storage container 51. When the mixed fluid collides with the first wall 60a, its direction of travel changes, and it collides with the inner surface of the storage container 51. The lubricating oil contained in the mixed fluid adheres to the inner surface of the storage container 51, separating the lubricating oil from the refrigerant. This separation of the lubricating oil contained in the mixed fluid from the refrigerant occurs in two stages, thereby improving the recovery rate of the lubricating oil.

[0062] like Figure 2 As shown, a demister 65 is disposed in the pipe 58a constituting the refrigerant outlet 58. The demister 65 captures mist-like lubricating oil contained in the refrigerant vapor and can separate the lubricating oil from the refrigerant vapor. As a result, the recovery rate of the lubricating oil can be improved.

[0063] Figure 5 1 is a cross-sectional view showing another embodiment of the oil tank 30. Details of this embodiment not specifically described are similar to those in the reference Figures 2 to 4 The embodiments described are identical, so repeated descriptions are omitted. In this embodiment, the oil inlet 54 is located below the first wall 60a and faces the lower surface of the first wall 60a. The first wall 60a of the baffle 60 is positioned between the oil inlet 54 and the mixed fluid inlet 56. Therefore, collision between the lubricating oil in the storage container 51 and the mixed fluid is prevented by the first wall 60a of the baffle 60.

[0064] Figure 61 is a cross-sectional view showing another embodiment of the oil tank 30. Details of this embodiment not specifically described are similar to those in the reference Figures 2 to 4 The embodiments described are identical, so repeated descriptions are omitted. In this embodiment, the oil inlet 54 is located below the first wall 60a and extends parallel to the first wall 60a. The first wall 60a of the baffle 60 is located between the oil inlet 54 and the mixed fluid inlet 56. Therefore, the first wall 60a of the baffle 60 prevents collision between the lubricating oil in the storage container 51 and the mixed fluid.

[0065] Figure 7 is a cross-sectional view showing yet another embodiment of the oil tank 30. Figure 8 yes Figure 7 The details of this embodiment not specifically described are the same as those in the reference Figures 2 to 4 The embodiments described are identical, so repetitive descriptions are omitted. In this embodiment, the mixed fluid inlet 56 is fixed to the third wall 60c and configured to allow the mixed fluid to flow toward the inner surface of the second wall 60b. The mixed fluid inlet 56 extends through the side wall 51b of the storage container 51. The front end of the mixed fluid inlet 56 is located above the first wall 60a and connected to the third wall 60c. The mixed fluid inlet 56 faces the inner surface of the second wall 60b.

[0066] According to this embodiment, the mixed fluid with a relatively high flow rate collides with the inner surface of the second wall 60b, and the first wall 60a prevents the mixed fluid from colliding with the oil surface in the storage container 51. Therefore, the scattering of the lubricating oil is suppressed, the oil surface is stabilized, and the lubricating oil can be stably supplied to the sliding part of the compressor 1. In addition, as Figure 8 As shown, when the mixed fluid collides with the second wall 60b, the lubricating oil contained in the mixed fluid adheres to the second wall 60b, separating the lubricating oil from the refrigerant. The lubricating oil flows downward on the second wall 60b, then flows on the first wall 60a, and falls into the storage container 51. When the mixed fluid collides with the second wall 60b, its direction of travel changes, and it collides with the inner surface of the storage container 51. The lubricating oil contained in the mixed fluid adheres to the inner surface of the storage container 51, separating the lubricating oil from the refrigerant. This separation of the lubricating oil contained in the mixed fluid from the refrigerant occurs in two stages, thereby improving the recovery rate of the lubricating oil.

[0067] exist Figure 7In the illustrated embodiment, both the mixed fluid inlet 56 and the oil inlet 54 face the refrigerant outlet 58, with the mixed fluid inlet 56 located between them. With respect to the flow of refrigerant vapor within the storage container 51, the mixed fluid inlet 56 is located downstream, while the oil inlet 54 is located upstream. This arrangement directs the lubricating oil into an area with a lower refrigerant vapor flow rate. Consequently, the lubricating oil is less likely to be agitated by the refrigerant vapor, preventing atomization of the lubricating oil. Consequently, the recovery rate of the lubricating oil is improved.

[0068] Figure 9 1 is a cross-sectional view showing another embodiment of the oil tank 30. Details of this embodiment not specifically described are similar to those in the reference Figure 7 as well as Figure 8 The embodiments described are the same, so repeated descriptions are omitted. In this embodiment, the baffle 60 has a first wall 60a and a second wall 60b, but does not have a third wall 60c. The first wall 60a is fixed to the side wall 51b of the storage container 51. The second wall 60b is separate from the upper wall 51a of the storage container 51, but may also be fixed to the upper wall 51a.

[0069] The mixed fluid inlet 56 and the oil inlet 54 are fixed to the side wall 51 b of the storage container 51 .

[0070] The mixed fluid inlet 56 faces the inner surface of the second wall 60b. The oil inlet 54 is arranged below the first wall 60a and extends parallel to the first wall 60a. In one embodiment, it can also be Figure 5 In the same manner as in the illustrated embodiment, the oil inlet 54 is arranged toward the lower surface of the first wall 60 a.

[0071] according to Figure 9 The embodiment shown can be obtained with reference to Figure 7 as well as Figure 8 The first wall 60a of the baffle 60 is located between the oil inlet 54 and the mixed fluid inlet 56. Therefore, the first wall 60a of the baffle 60 prevents the lubricating oil in the storage container 51 from colliding with the mixed fluid.

[0072] Figure 10 1 is a cross-sectional view showing another embodiment of the oil tank 30. Details of this embodiment not specifically described are similar to those in the reference Figure 9 The embodiments described are the same, so duplicate descriptions are omitted. In this embodiment, the mixed fluid inlet 56 is located on one sidewall 51b of the storage container 51, and the oil inlet 54 is located on the opposite sidewall 51c of the storage container 51. In other words, the mixed fluid inlet 56 and the oil inlet 54 are located on both sides of the storage container 51.

[0073] The first wall 60a of the baffle 60 is fixed to the side wall 51b of the storage container 51, and the second wall 60b of the baffle 60 is separated from the upper wall 51a of the storage container 51. In one embodiment, the second wall 60b can also be fixed to the upper wall 51a of the storage container 51. In addition, as Figure 11 As shown, in one embodiment, the first wall 60 a of the baffle 60 may also be separated from the side wall 51 b of the storage container 51 , and the second wall 60 b of the baffle 60 is fixed to the upper wall 51 a of the storage container 51 .

[0074] According to this embodiment, the mixed fluid inlet 56 is separated from the oil inlet 54, so the lubricating oil is introduced into an area with a lower refrigerant vapor velocity. This makes the lubricating oil less likely to be agitated by the refrigerant vapor, thus preventing the lubricating oil from atomizing. As a result, the recovery rate of the lubricating oil is improved.

[0075] The oil tank 30 in each of the above embodiments is an external oil tank arranged outside the compressor 1 , but the above structures and functions can all be applied to a built-in oil tank arranged inside the compressor 1 , and the same effects can be achieved.

[0076] In addition, the oil tank 30 of each embodiment described above can also be applied to Figure 12 Other embodiments of the centrifugal refrigerator shown. Figure 12 In the embodiment shown, in addition to the mixed fluid recovery line 38 described above, an oil recovery line 70 is further provided. The oil recovery line 70 extends from the compressor 1 to the oil tank 30 via an ejector 73. More specifically, one end of the oil recovery line 70 is connected to the oil reservoir 72 of the compressor 1, and the other end of the oil recovery line 70 is connected to the mixed fluid inlet 56 of the oil tank 30 (see FIG. Figure 2 etc.). The oil reservoir 72 is located between the suction port of the compressor 1 and the first-stage impeller 11 of the compressor 1. Although a small amount of lubricating oil is mixed in the refrigerant vapor transferred from the evaporator 2 to the compressor 1. The lubricating oil flowing into the compressor 1 is accumulated in the oil reservoir 72 and is transported to the oil tank 30 through the oil recovery line 70. The working fluid line 75 branches from the refrigerant piping 4B and is connected to the ejector 73. A portion of the refrigerant vapor flowing from the compressor 1 to the condenser 3 is injected into the ejector 73 from the refrigerant piping 4B through the working fluid line 75 and acts as the working fluid of the ejector 73. The ejector 73 sucks in the lubricating oil retained in the oil reservoir 72 and transfers the lubricating oil to the oil tank 30.

[0077] The above-described embodiments are described with the goal of enabling those with ordinary knowledge in the technical field to which the present invention pertains to the implementation of the present invention. Various modifications of the above-described embodiments can naturally be implemented by those skilled in the art, and the technical concept of the present invention can also be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments and should be interpreted within the broadest scope of the technical concept defined by the claims.

Claims

1. An oil tank for storing lubricating oil for lubricating the sliding parts of a compressor used in a centrifugal refrigerator, characterized in that: have: a storage container for storing lubricating oil therein; an oil inlet for returning the lubricating oil supplied to the sliding portion to the storage container; a mixed fluid inlet for introducing a mixed fluid of refrigerant liquid and lubricating oil into the storage container; a refrigerant outlet for releasing refrigerant vapor in the storage container; as well as a structure that prevents the lubricating oil flowing into the storage container from the oil inlet from colliding with the mixed fluid flowing into the storage container from the mixed fluid inlet, The structure is a baffle disposed in the storage container. At least a portion of the baffle is disposed between the oil inlet and the mixed fluid inlet. The baffle includes a first wall arranged substantially horizontally and a second wall extending upward from the first wall. The mixed fluid inlet is configured to allow the mixed fluid to flow toward the upper surface of the first wall, The second wall is located between the refrigerant outlet and the mixed fluid inlet, The oil inlet is arranged toward the lower surface of the first wall.

2. The fuel tank according to claim 1, characterized in that A demister is further provided, which is arranged in the pipe constituting the refrigerant outlet.

3. An oil tank for storing lubricating oil for lubricating the sliding parts of a compressor used in a centrifugal refrigerator, characterized in that: have: a storage container for storing lubricating oil therein; an oil inlet for returning the lubricating oil supplied to the sliding portion to the storage container; a mixed fluid inlet for introducing a mixed fluid of refrigerant liquid and lubricating oil into the storage container; a refrigerant outlet for releasing refrigerant vapor in the storage container; as well as a structure that prevents the lubricating oil flowing into the storage container from the oil inlet from colliding with the mixed fluid flowing into the storage container from the mixed fluid inlet, The structure is a baffle disposed in the storage container. At least a portion of the baffle is disposed between the oil inlet and the mixed fluid inlet. The baffle includes a first wall arranged substantially horizontally and a second wall extending upward from the first wall. The mixed fluid inlet is configured to allow the mixed fluid to flow toward the upper surface of the first wall, The second wall is located between the refrigerant outlet and the mixed fluid inlet, The baffle further includes a third wall extending upward from the first wall. The mixed fluid inlet is located between the second wall and the third wall, The third wall is located between the mixed fluid inlet and the oil inlet, The oil inlet is arranged toward the outer surface of the third wall.

4. An oil tank for storing lubricating oil for lubricating the sliding parts of a compressor used in a centrifugal refrigerator, characterized in that: have: a storage container for storing lubricating oil therein; an oil inlet for returning the lubricating oil supplied to the sliding portion to the storage container; a mixed fluid inlet for introducing a mixed fluid of refrigerant liquid and lubricating oil into the storage container; a refrigerant outlet for releasing refrigerant vapor in the storage container; as well as a structure that prevents the lubricating oil flowing into the storage container from the oil inlet from colliding with the mixed fluid flowing into the storage container from the mixed fluid inlet, The structure is a baffle disposed in the storage container. At least a portion of the baffle is disposed between the oil inlet and the mixed fluid inlet. The mixed fluid inlet and the oil inlet are directed toward the refrigerant outlet, The mixed fluid inlet is located between the oil inlet and the refrigerant outlet.

5. An oil tank for storing lubricating oil for lubricating the sliding parts of a compressor used in a centrifugal refrigerator, characterized in that: have: a storage container for storing lubricating oil therein; an oil inlet for returning the lubricating oil supplied to the sliding portion to the storage container; a mixed fluid inlet for introducing a mixed fluid of refrigerant liquid and lubricating oil into the storage container; a refrigerant outlet for releasing refrigerant vapor in the storage container; as well as a structure that prevents the lubricating oil flowing into the storage container from the oil inlet from colliding with the mixed fluid flowing into the storage container from the mixed fluid inlet, The structure is a baffle disposed in the storage container. At least a portion of the baffle is disposed between the oil inlet and the mixed fluid inlet. The baffle includes a first wall arranged substantially horizontally and a second wall extending upward from the first wall. The mixed fluid inlet is located above the first wall and is configured to allow the mixed fluid to flow toward the second wall. The second wall is located between the refrigerant outlet and the mixed fluid inlet.

6. The fuel tank according to claim 5, characterized in that The oil inlet is arranged below the first wall.

7. A centrifugal refrigerator, characterized in that: have: an evaporator that evaporates refrigerant liquid to generate refrigerant vapor; a compressor for compressing the refrigerant vapor; a condenser that condenses the compressed refrigerant vapor to generate the refrigerant liquid; as well as an oil tank for storing lubricating oil for lubricating the sliding parts of the compressor, The fuel tank is the fuel tank according to any one of claims 1 to 6.

8. The centrifugal refrigerator according to claim 7, wherein: The mixed fluid inlet of the oil tank is connected to a mixed fluid recovery line extending from the evaporator.

9. The centrifugal refrigerator according to claim 7, wherein: The mixed fluid inlet of the oil tank is connected to an oil recovery line extending from an oil reservoir of the compressor.

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