Compressor oil separator and compressor for very low temperature refrigerators

Abstract

An oil separator (10) mounted on a compressor for a very low temperature refrigerator includes a first cylindrical portion (11) having a cylindrical shape extending in a vertical direction and having a first communication portion (11a) communicating an inside and an outside of the first cylindrical portion (11), an introduction pipe (12) extending in the vertical direction and introducing oil-containing refrigerant into the first cylindrical portion (11), and a filter member (13) located between the first cylindrical portion (11) and the introduction pipe (12) in a cross section intersecting the vertical direction. The introduction pipe (12) has an introduction port (12a) introducing the refrigerant into the first cylindrical portion (11). The introduction port (12a) is located at a position lower than a center of the first cylindrical portion (11) in the vertical direction.

Description

TECHNICAL FIELD

[0001] The present application relates to a compressor for a cryogenic refrigerator and an oil separator for a compressor for a cryogenic refrigerator. BACKGROUND

[0002] An oil separator is provided to a compressor for a cryogenic refrigerator. The oil separator is provided with a filter device. The filter device is provided with a first cylindrical portion, a second cylindrical portion, a filter member, and an introduction pipe for refrigerant. In the filter device, the first cylindrical portion is located at the outermost side in the radial direction. The second cylindrical portion is located inside the first cylindrical portion, and the filter member is located between the second cylindrical portion and the first cylindrical portion. The lower end of the introduction pipe is located inside the second cylindrical portion, and the introduction port of the lower end of the introduction pipe is located at the upper end of the second cylindrical portion. The first cylindrical portion and the second cylindrical portion each have a plurality of through-holes that penetrate the cylindrical portion. The refrigerant introduced into the filter device from the introduction port reaches the filter member through the through-holes of the second cylindrical portion. The refrigerant is separated into oil and cooling gas in the filter member. The oil captured by the filter member is accumulated below the filter member by moving inside the filter member by its own weight, and is discharged from below the filter member to the outside of the filter device (for example, refer to Patent Literature 1).

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Laid-Open No. 2008-039222 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] Furthermore, since the introduction port of the introduction pipe of the filter device is located at the upper end of the second cylindrical portion, the refrigerant discharged from the introduction port into the second cylindrical portion easily moves from above the second cylindrical portion toward above the filter member. Thus, the oil captured by the filter member needs to move from above the filter member toward below the filter member in a large amount. By this, the amount of oil that should be discharged from the filter member does not easily accumulate below the filter member, and as a result, the oil does not easily discharge from the filter device or even the oil separator.

[0008] An object of the present application is to provide an oil separator for a compressor and a compressor for a cryogenic refrigerator that can easily discharge oil from the oil separator.

[0009] TECHNICAL SOLUTION

[0010] The oil separator for a compressor according to one embodiment includes a first cylindrical portion having a cylindrical shape, extending in a vertical direction, and having a first communication portion that communicates an inside and an outside of the first cylindrical portion; an introduction pipe extending in the vertical direction and introducing a refrigerant containing oil into the first cylindrical portion; and a filter member, in a cross section intersecting the vertical direction, positioned between the first cylindrical portion and the introduction pipe. The oil separator for a compressor is mounted on a compressor for a very low temperature refrigerator. The introduction pipe has an introduction port that introduces the refrigerant into the first cylindrical portion. The introduction port is positioned lower than a center of the first cylindrical portion in the vertical direction.

[0011] The compressor for a very low temperature refrigerator according to one embodiment includes the oil separator for a compressor described above. With the oil separator for a compressor described above, because the introduction port is positioned lower than the center of the first cylindrical portion in the vertical direction, the refrigerant discharged from the introduction port is more likely to be supplied to a lower side of the filter member than to an upper side of the filter member. Thus, oil is likely to accumulate on the lower side of the filter member, and the oil accumulated on the filter member is likely to be discharged to the outside of the first cylindrical portion through the first communication portion of the first cylindrical portion. Thus, the oil separated from the refrigerant in the oil separator is likely to be discharged to the outside of the oil separator.

[0012] In the oil separator for a compressor described above, the introduction port can include a hole that penetrates the introduction pipe in a direction intersecting the vertical direction. With the oil separator for a compressor described above, the introduction pipe can increase the amount of the refrigerant discharged from the introduction port toward the lower side of the filter member compared to a case where the introduction port is provided only at an end portion. Thus, the oil captured by the filter member is likely to accumulate on the lower side of the filter member.

[0013] In the oil separator for a compressor described above, the introduction port is constituted by one or more holes that penetrate the introduction pipe in a direction intersecting the vertical direction. The introduction pipe has an end portion positioned in the first cylindrical portion. The introduction pipe can include a cover portion that plugs the end portion.

[0014] With the oil separator for a compressor described above, the refrigerant discharged from the introduction port to the outside of the introduction pipe is more likely to be discharged to the lower side of the filter member than to the upper side of the filter member. Thus, the distribution of the amount of the oil captured in the filter member becomes larger from the upper side toward the lower side. Thus, because the amount of the oil captured is smaller on the upper side of the filter member than on the lower side of the filter member, the passage of the cooling gas separated from the oil on the upper side of the filter member is less likely to be obstructed by the oil. In addition, because the amount of the oil captured is larger on the lower side of the filter member than on the upper side of the filter member, the distance that the oil moves by its own weight is shortened, and the oil is more likely to be discharged to the outside of the oil separator.

[0015] In the above-described compressor oil separator, the introduction pipe can also extend from the lower side in the vertical direction toward the upper side to a position in the vertical direction that is lower than the center of the first cylindrical portion. With this compressor oil separator, the refrigerant flowing through the introduction pipe is introduced into the first cylindrical portion from the lower side in the vertical direction toward the upper side. Thus, since the refrigerant is easily supplied from the upper side to the lower side of the filter member, the area of the filter member that is not used for separating oil can be reduced. As a result, the efficiency of the filter member in separating oil can be improved.

[0016] In the above-described compressor oil separator, the introduction port can also be formed by a plurality of circular holes that penetrate the introduction pipe in a direction that intersects the vertical direction, the plurality of circular holes being located in the outer peripheral surface of the introduction pipe at a portion near the end portion of the introduction pipe.

[0017] With the above-described compressor oil separator, since the introduction port is formed by a plurality of holes, even if the refrigerant is difficult to discharge from one hole, the refrigerant can still be discharged from the other holes. Furthermore, since the plurality of circular holes are located near the end portion, compared to when the plurality of circular holes are located at a position that is further lower, the area of the filter member that captures oil in the vertical direction can be increased.

[0018] In the above-described compressor oil separator, a second cylindrical portion can also be further provided, which extends in the vertical direction and is located between the introduction pipe and the filter member in a cross section that intersects the vertical direction, the second cylindrical portion having an opposing portion that opposes the introduction port in a direction that intersects the vertical direction, and a second communication portion that communicates the inside of the second cylindrical portion with the outside, except for the opposing portion.

[0019] With the above-described compressor oil separator, since the second communication portion is not in the opposing portion, of the refrigerant that is discharged from the introduction port, the refrigerant that is discharged toward the opposing portion collides with the opposing portion. Thus, the refrigerant that is discharged toward the opposing portion moves toward the filter member in a direction that is lower than the opposing portion. As a result, the distance that the oil that is captured by the filter member moves by its own weight can be reduced, and the oil can be easily guided to the outside of the oil separator. Furthermore, since the cooling gas that is separated from the oil easily passes through the filter, the cooling gas can be easily guided to the outside of the oil separator. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 FIG. 1 is a cross-sectional view that shows the structure of a compressor oil separator according to a first embodiment.

[0021] Figure 2 FIG. 2 is an action diagram for explaining the action of the compressor oil separator according to the first embodiment.

[0022] Figure 3is a sectional view showing the structure of the oil separator for a compressor according to the second embodiment.

[0023] Figure 4 is a functional diagram for explaining the function of the oil separator for a compressor according to the second embodiment. DETAILED DESCRIPTION

[0024] [First Embodiment]

[0025] REFERENCE Figure 1 AND Figure 2 The first embodiment of the oil separator for a compressor and the compressor for a cryogenic refrigerator will be described. The oil separator for a compressor described below is provided in a cryogenic refrigerator mounted on a cryogenic pump. In addition, the oil separator for a compressor described below is provided in a compressor for a cryogenic refrigerator mounted on a cryogenic pump. Figure 1 For the convenience of showing the structure of each member provided in the oil separator, the sectional structure and the end surface structure of each of the first cylindrical portion and the second cylindrical portion are shown.

[0026] As shown in Figure 1 , the oil separator for a compressor 10 is provided with a first cylindrical portion 11, an introduction pipe 12, and a filter member 13. The first cylindrical portion 11 has a cylindrical shape extending in the vertical direction and is provided with a first communication portion 11a that communicates the inside and the outside of the first cylindrical portion 11. The introduction pipe 12 extends in the vertical direction and introduces oil-containing refrigerant into the first cylindrical portion 11. The filter member 13 is located between the first cylindrical portion 11 and the introduction pipe 12 in a sectional plane intersecting the vertical direction. The introduction pipe 12 is provided with an introduction port 12a that introduces refrigerant into the first cylindrical portion 11. The introduction port 12a is located at a position lower than the center of the first cylindrical portion 11 in the vertical direction.

[0027] Since the introduction port 12a is located at a position lower than the center of the first cylindrical portion 11 in the vertical direction, refrigerant discharged from the introduction port 12a is more likely to be supplied to the lower side of the filter member 13 than to the upper side of the filter member 13. Thus, oil is likely to accumulate on the lower side of the filter member 13, and the oil accumulated in the filter member 13 is likely to be discharged to the outside of the first cylindrical portion 11 through the first communication portion 11a of the first cylindrical portion 11. Thus, in the oil separator 10, oil separated from the refrigerant is likely to be discharged to the outside of the oil separator 10.

[0028] The introduction pipe 12 extends from the lower side to the upper side in the vertical direction to a position lower than the center of the first cylindrical portion 11 in the vertical direction. Thus, refrigerant flowing through the introduction pipe 12 is introduced into the first cylindrical portion 11 from the lower side to the upper side in the vertical direction. Thus, since refrigerant is likely to be supplied from the upper side to the lower side of the filter member 13, the area of the filter member 13 that is not used for separating oil can be reduced. As a result, the efficiency of the filter member 13 in separating oil can be improved.

[0029] The refrigerant is a cooling gas containing the oil. The cooling gas is, for example, helium. The compressor provided with the oil separator 10 is provided with a pump that pressurizes the refrigerant at a position upstream of the oil separator 10 in the passage through which the refrigerant flows. The refrigerant reaches the oil separator 10 in a pressurized state, and the pressurized refrigerant is discharged from the introduction port 12a of the introduction pipe 12 into the first cylindrical portion 11.

[0030] The oil separator 10 further includes a second cylindrical portion 14 and a housing 15. The second cylindrical portion 14 is positioned between the introduction pipe 12 and the filter member 13 in a cross section orthogonal to the vertical direction. The second cylindrical portion 14 includes a second communication portion 14a that communicates the inside and the outside of the second cylindrical portion 14 in a direction orthogonal to the vertical direction. The housing 15 is positioned outside the first cylindrical portion 11.

[0031] The first cylindrical portion 11 has a cylindrical shape. The first communication portion 11a of the first cylindrical portion 11 is formed of a plurality of penetration holes that penetrate the first cylindrical portion 11 in the radial direction of the first cylindrical portion 11. The plurality of penetration holes are regularly arranged in the vertical direction and the radial direction (or the circumferential direction) of the first cylindrical portion 11. For example, the first cylindrical portion 11 is formed by forming a cylindrical shape from a punched metal having a plate shape. Alternatively, the first cylindrical portion 11 can be formed of a pipe member made of metal, in which case the plurality of penetration holes are formed in the pipe member.

[0032] The second cylindrical portion 14 has a cylindrical shape. The second cylindrical portion 14 is disposed in the first cylindrical portion 11 such that the axis of the second cylindrical portion 14 coincides with the axis of the first cylindrical portion 11. The length of the second cylindrical portion 14 in the vertical direction is equal to the length of the first cylindrical portion 11. The second communication portion 14a of the second cylindrical portion 14 is formed of a plurality of penetration holes that penetrate the second cylindrical portion 14 in the radial direction of the second cylindrical portion 14, like the first communication portion 11a. The plurality of penetration holes are regularly arranged in the vertical direction and the radial direction (or the circumferential direction) of the second cylindrical portion 14. For example, the second cylindrical portion 14 is formed by forming a cylindrical shape from a punched metal having a plate shape. Alternatively, the second cylindrical portion 14 can be formed of a pipe member made of metal, in which case the plurality of penetration holes are formed in the pipe member.

[0033] The introduction pipe 12 has a cylindrical shape. A portion of the introduction pipe 12 is positioned in the second cylindrical portion 14. The portion of the introduction pipe 12 positioned in the second cylindrical portion 14 is disposed in the second cylindrical portion 14 such that the axis of the introduction pipe 12 coincides with the axis of the second cylindrical portion 14. The introduction pipe 12 has two end portions, an upper end portion and a lower end portion, Figure 1For example, the upper end portion is located inside the second cylindrical portion 14. The aforementioned introduction port 12a is located at the upper end portion of the introduction pipe 12 and opens upward. That is, in the first embodiment, the introduction port 12a of the introduction pipe 12 is composed of one opening, and the introduction port 12a allows the refrigerant to pass from the lower side in the vertical direction toward the upper side. The introduction pipe 12 is composed of, for example, a pipe made of metal.

[0034] The aforementioned first cylindrical portion 11, second cylindrical portion 14, and introduction pipe 12 are members that constitute the filter device 10F. In the filter device 10F, the end portion on the upper side of the first cylindrical portion 11 and the end portion on the upper side of the second cylindrical portion 14 are plugged by one cover member. In contrast, the end portion on the lower side of the first cylindrical portion 11 and the end portion on the lower side of the second cylindrical portion 14 are plugged by one cover member. The filter device 10F is supported together with the introduction pipe 12 by the support portion 15c1.

[0035] The filter member 13 is located in the radial direction of the first cylindrical portion 11 between the first cylindrical portion 11 and the second cylindrical portion 14. The filter member 13 separates the oil contained in the refrigerant from the cooling gas. When the refrigerant is supplied to the filter member 13, only the oil in the refrigerant is captured by the filter member 13, and, on the other hand, the cooling gas contained in the refrigerant is not captured by the filter member 13. Thus, the filter member 13 separates the oil from the cooling gas. The filter member 13 is, for example, glass fiber. The filter member 13 is located in the entire space between the first cylindrical portion 11 and the second cylindrical portion 14.

[0036] The housing 15 has a body portion 15a, an upper side cover portion 15b, and a lower side cover portion 15c. The body portion 15a has a cylindrical shape that extends in the vertical direction and houses the filter device 10F. In the body portion 15a, the upper end in the vertical direction is plugged by the upper side cover portion 15b, and the lower end in the vertical direction is plugged by the lower side cover portion 15c. The upper side cover portion 15b has a support portion 15b1 that supports a gas discharge pipe 16 for discharging the cooling gas. The lower side cover portion 15c has the aforementioned support portion 15c1. The lower side cover portion 15c supports an oil discharge pipe 17 for discharging the oil.

[0037] Figure 2 is a view for explaining the operation of the oil separator 10. Figure 2 In order to facilitate the explanation of the operation of the oil separator 10, the oil OL contained in the refrigerant is represented by a hollow circle, and the trajectory of the refrigerant introduced into the filter device 10F from the introduction port 12a is represented by an arrow.

[0038] As Figure 2As shown, in the oil separator 10, refrigerant is introduced from the inlet 12a, which is located below the center of the first cylindrical portion 11 in the vertical direction, and from below upwards in the vertical direction. Therefore, the refrigerant discharged from the inlet 12a is dispersed throughout the entire filter element 13 in the vertical direction via the second cylindrical portion 14. This reduces the area in the filter element 13 that is unfavorable for separating oil OL, thereby improving the efficiency of the filter device 10F in separating oil OL.

[0039] The oil OL captured by the filter element 13 moves to the bottom of the filter element 13 by its own weight, and thus, the oil OL accumulates at the bottom of the filter element 13. The oil OL accumulated at the bottom of the filter element 13 is discharged to the outside of the filter device 10F through the first connecting portion 11a of the first cylindrical portion 11. The oil OL discharged to the outside of the filter device 10F accumulates on the lower side cover portion 15c of the housing 15, and is discharged to the outside of the oil separator 10 through the oil discharge pipe 17 supported by the lower side cover portion 15c. In contrast, the cooling gas separated from the oil OL by the filter device 10F is discharged to the outside of the oil separator 10 through the gas discharge pipe 16.

[0040] As explained above, when using the first embodiment of the compressor oil separator and the ultra-low temperature refrigeration compressor, the following effects can be obtained.

[0041] (1-1) Because the inlet 12a of the inlet pipe 12 is located below the center of the first cylindrical portion 11, more refrigerant discharged from the inlet 12a is supplied to the lower part of the filter member 13 than to the upper part. Consequently, because oil OL tends to accumulate below the filter member 13, the oil OL accumulated in the filter member 13 is easily discharged to the outside of the first cylindrical portion 11 through the first connecting portion 11a of the first cylindrical portion 11. As a result, in the oil separator 10, the oil OL separated from the refrigerant is easily discharged to the outside of the oil separator 10.

[0042] (1-2) The inlet pipe 12 extends vertically upward from below and is inserted into the first cylindrical portion 11 from its lower end. The inlet port 12a is located below the center of the first cylindrical portion 11 in the vertical direction. Therefore, the refrigerant flows vertically upward through the inlet pipe 12 and is introduced into the first cylindrical portion 11 (see reference). Figure 2 By supplying refrigerant throughout the filter element 13 from top to bottom, the area within the filter element 13 that is unfavorable for separating oil OL can be reduced. As a result, the efficiency of the filter element 13 in separating oil OL can be improved.

[0043] Alternatively, the first embodiment described above can also be implemented with the following modifications.

[0044] [Import tube]

[0045] The introduction pipe 12 can also extend from the upper side toward the lower side in the vertical direction and have an introduction port 12a at a position lower than the center of the first cylindrical portion 11 in the vertical direction. That is, the introduction pipe 12 can also introduce refrigerant into the first cylindrical portion 11 from the upper side toward the lower side in the vertical direction. In this case, since the introduction pipe 12 has the introduction port 12a at a position lower than the center of the first cylindrical portion 11 in the vertical direction, the same effects as those of (1-1) above can also be obtained.

[0046] [Second Embodiment]

[0047] Reference Figure 3 and Figure 4 A second embodiment of the oil separator for a compressor and the compressor for a very low temperature refrigerator will be described. The oil separator for a compressor of the second embodiment differs from the oil separator for a compressor of the first embodiment in the structure of the introduction pipe provided to the filter device and the structure of the second cylindrical portion. Hereinafter, the differences between the oil separator for a compressor of the second embodiment and the oil separator for a compressor of the first embodiment will be described in detail. In addition, in the oil separator for a compressor of the second embodiment, the same reference numerals are attached to the members common to the oil separator for a compressor of the first embodiment, and detailed description of the members will be omitted.

[0048] In addition, Figure 3 are to facilitate the representation of the structure of each member provided to the oil separator, the cross-sectional structure and the end surface structure of the first cylindrical portion are represented. Furthermore, Figure 3 in which the cross-sectional structure and the end surface structure of the second cylindrical portion are represented on one side (the left side) with respect to the axis of the second cylindrical portion, and the cross-sectional structure of the second cylindrical portion is represented on the other side (the right side).

[0049] As shown in Figure 3 , like the oil separator 10 of the first embodiment, the oil separator 20 is provided with a first cylindrical portion 11, an introduction pipe 22, and a filter member 13. Like the first embodiment, the introduction port 22a of the introduction pipe 22 is also located at a position lower than the center of the first cylindrical portion 11 in the vertical direction. The introduction port 22a of the introduction pipe 22 is constituted by one or more holes that penetrate the introduction pipe 22 in a direction intersecting the vertical direction. The introduction pipe 22 of the second embodiment has a cylindrical shape, and the introduction port 22a is constituted by one or more holes that penetrate the introduction pipe 22 in the radial direction of the introduction pipe 22. The introduction pipe 22 has an end portion located inside the first cylindrical portion 11, and is provided with a cover portion 22b that plugs the end portion. That is, Figure 3 the example of FIG. 8A is to occlude the upper end surface of the introduction pipe 22.

[0050] Because the inlet pipe 22 has the aforementioned inlet 22a and cover 22b, the refrigerant discharged from the inlet 22a to the outside of the inlet pipe 22 is more easily discharged to the bottom of the filter member 13 than to the top of the filter member 13. As a result, the amount of oil captured in the filter member 13 is distributed in a way that increases from top to bottom.

[0051] Therefore, the higher up the filter element 13, the smaller the amount of oil captured, thereby preventing oil from obstructing the passage of cooling gas separated from the refrigerant above the filter element 13. Conversely, the lower down the filter element 13, the larger the amount of oil captured, thereby shortening the distance the oil travels by its own weight and making it easier to discharge the oil to the outside of the oil separator 20.

[0052] exist Figure 3 In the example shown, the inlet 22a is composed of a plurality of circular holes extending through the inlet tube 22 along its radial direction. These circular holes are located on the outer peripheral surface of the inlet tube 22, near its end. That is, in Figure 3 In this example, the inlet 22a is located on the outer peripheral surface of the inlet pipe 22 near the upper end. Since the inlet 22a is composed of multiple holes, even if it is difficult to discharge refrigerant from one hole, refrigerant can still be discharged from the other holes. Furthermore, since the multiple circular holes are located near the upper end, the area for capturing oil in the filter member 13 in the vertical direction can be expanded compared to when the multiple circular holes are located in a lower position.

[0053] exist Figure 3 In the example shown, multiple circular holes are spaced apart in the circumferential direction of the inlet pipe 22 and also spaced apart in the axial direction of the inlet pipe 22. Therefore, it is possible to suppress the amount of refrigerant discharged from the inlet pipe 22 from being biased in the circumferential direction of the inlet pipe 22.

[0054] The second cylindrical portion 24 includes a corresponding portion 24b, which comprises a portion opposite to the inlet 22a in a direction intersecting the vertical direction. In the second embodiment, the second cylindrical portion 24 is cylindrical, and the corresponding portion 24b is opposite to the inlet 22a in the radial direction of the second cylindrical portion 24. The portion of the second cylindrical portion 24 other than the corresponding portion 24b includes a second connecting portion 24a that connects the inside and outside of the second cylindrical portion 24. That is, the second cylindrical portion 24 includes two non-corresponding portions 24c separated by the corresponding portion 24b in the vertical direction. The second connecting portion 24a is composed of a plurality of holes, with a first group of holes located at the upper non-corresponding portions 24c and a second group of holes located at the lower non-corresponding portions 24c.

[0055] Since the second communication portion 24a is not in the opposite portion 24b, of the refrigerant discharged from the guide inlet 22a, the refrigerant discharged toward the opposite portion 24b collides with the opposite portion 24b. By this, the refrigerant discharged toward the opposite portion 24b moves in a direction toward a lower side than the opposite portion 24b to the filter member 13. Thus, the distance by which the oil captured by the filter member 13 moves by its own weight can be shortened, and the oil can be easily guided to the outside of the oil separator 20. Further, since the cooling gas separated from the refrigerant easily passes through the filter member 13, the cooling gas can be easily guided to the outside of the oil separator 20.

[0056] Also, as with the second cylindrical portion 14 of the first embodiment, the second cylindrical portion 24 can also be formed of a plate member made of metal or a pipe member made of metal. In this case, by not forming a hole in the portion of the plate member or the pipe member corresponding to the opposite portion 24b, a second cylindrical portion 24 provided with the opposite portion 24b and the non-opposite portion 24c can be formed. Further, the second cylindrical portion 24 can also be formed of a plate member having holes formed in the vertical direction and a plate member having no holes. At this time, it is only necessary to arrange the plate member having no holes in the portion of the plate member having holes corresponding to the opposite portion 24b.

[0057] Figure 4 is a view for explaining the action of the oil separator 20. As with Figure 2 , Figure 4 in order to facilitate explanation of the action of the oil separator 20, the oil OL contained in the refrigerant is indicated by a hollow circle, and the trajectory of the refrigerant introduced from the guide inlet 22a into the filter device 20F is indicated by an arrow.

[0058] As Figure 4 indicated, the oil separator 20 is such that, by the refrigerant discharged from the guide inlet 22a colliding with the opposite portion 24b, the refrigerant is caused to easily move toward a lower side than the opposite portion 24b. By this, as to the amount of capture of the oil OL in the filter member 13, a distribution is produced in which the more the lower side of the filter member 13, the greater the amount of capture of the oil OL. By this, the more the upper side of the filter member 13, the smaller the amount of capture of the oil OL, and thus the passage of the cooling gas separated from the refrigerant above the filter member 13 can be inhibited by the oil OL. Also, the more the lower side of the filter member 13, the smaller the amount of capture of the oil OL, and thus the distance by which the oil OL moves by its own weight can be shortened, and the oil OL can be easily guided to the outside of the oil separator 20.

[0059] As explained above, when the second embodiment of the compressor oil separator and the compressor for a very low temperature refrigerator is employed, the effects described below can be obtained.

[0060] (2-1) Because the inlet 22a of the inlet pipe 22 is located below the center of the first cylindrical portion 11, more refrigerant discharged from the inlet 22a is supplied to the lower part of the filter member 13 than to the upper part. Consequently, because oil OL tends to accumulate below the filter member 13, the oil OL accumulated in the filter member 13 is easily discharged to the outside of the first cylindrical portion 11 through the first connecting portion 11a of the first cylindrical portion 11. As a result, in the oil separator 20, the oil OL separated from the refrigerant is easily discharged to the outside of the oil separator 20.

[0061] (2-2) The inlet pipe 22 extends vertically upward from below and is inserted into the first cylindrical portion 11 from one end. The inlet port 22a is located below the center of the first cylindrical portion 11 in the vertical direction. Therefore, the refrigerant flows vertically upward through the inlet pipe 22 and is introduced into the first cylindrical portion 11 (see reference). Figure 4 By supplying refrigerant throughout the filter element 13 from top to bottom, the area within the filter element 13 that is unfavorable for separating oil OL can be reduced. As a result, the efficiency of the filter element 13 in separating oil OL can be improved.

[0062] (2-3) The inlet 22a of the inlet pipe 22 includes one or more holes that penetrate the inlet pipe 22 in a direction intersecting the vertical direction. Compared with the case of using an inlet with an opening at the top, this structure can increase the amount of refrigerant discharged towards the bottom of the filter member 13, thus increasing the amount of oil OL captured below the filter member 13. Therefore, the higher up the filter member 13, the smaller the amount of oil OL captured, thereby suppressing the oil from obstructing the passage of the cooling gas separated from the refrigerant above the filter member 13. In addition, the lower down the filter member 13, the larger the amount of oil captured, thereby shortening the distance that the oil OL moves by its own weight, and making it easier to discharge the oil OL to the outside of the oil separator 20.

[0063] (2-4) The inlet 22a contains multiple holes. With this configuration, even if it is difficult to discharge refrigerant from one hole, refrigerant can still be discharged from the other holes. Furthermore, since multiple circular holes are located at the end of the inlet pipe 22 ( Figure 3 Near the upper middle part, therefore, compared with the multiple circular holes located further down, the area in the filter member 13 that captures oil OL in the vertical direction can be expanded.

[0064] (2-5)Of the refrigerant discharged from the introduction port 22a, the refrigerant discharged toward the opposite portion 24b collides with the opposite portion 24b and moves to the filter member 13 in a direction toward a lower side than the opposite portion 24b. Thus, the distance by which the oil OL captured by the filter member 13 moves by its own weight can be shortened, and the oil OL can be easily guided to the outside of the oil separator 20. Further, since the cooling gas separated from the refrigerant easily passes through the filter member 13, the cooling gas can be easily guided to the outside of the oil separator 20.

[0065] In addition, the second embodiment described above can be implemented by the following modifications.

[0066] [Inlet pipe]

[0067] The inlet pipe 22 of the second embodiment can further have the introduction port 12a of the inlet pipe 12 of the first embodiment. In this case, since the inlet pipe 22 includes a hole (the introduction port 22a) that penetrates the inlet pipe 22 in a direction intersecting the vertical direction, the effects described below can also be obtained.

[0068] (2-6)Since the inlet pipe 22 includes the introduction port 12a of the first embodiment in addition to the introduction port 22a of the second embodiment, the amount of refrigerant discharged toward the lower side of the filter member 13 and from the introduction ports 12a, 22a can be increased. By this means, the oil captured by the filter member 13 is easily accumulated on the lower side of the filter member 13.

[0069] Symbol explanation

[0070] 10, 20 Oil separator

[0071] 11 First cylindrical portion

[0072] 12, 22 Inlet pipe

[0073] 12a, 22a Introduction port

[0074] 13 Filter member

[0075] 14, 24 Second cylindrical portion

[0076] 24b Opposite portion

[0077] 15 Housing

[0078] 16 Gas guide pipe

[0079] 17 Oil guide pipe

Claims

1. An oil separator for a compressor, comprising: a first cylindrical portion having a cylindrical shape extending in a vertical direction and having a first communication portion that communicates an inside and an outside of the first cylindrical portion; an introduction pipe extending in the vertical direction and introducing an oil-containing refrigerant into the first cylindrical portion; and a filter member located between the first cylindrical portion and the introduction pipe in a cross section intersecting the vertical direction, wherein the oil separator for a compressor is mounted on a compressor for a very low temperature refrigerator, wherein the introduction pipe has an introduction port that introduces the refrigerant into the first cylindrical portion, the introduction port being located at a position lower than a center of the first cylindrical portion in the vertical direction, wherein the introduction port includes holes that penetrate the introduction pipe in a direction intersecting the vertical direction, wherein the oil separator further comprises a second cylindrical portion extending in the vertical direction and located between the introduction pipe and the filter member in a cross section intersecting the vertical direction, wherein the second cylindrical portion has an opposite portion opposite the introduction port in a direction intersecting the vertical direction, and has a second communication portion that communicates an inside and an outside of the second cylindrical portion, except for the opposite portion, wherein the introduction pipe has an end portion located in the first cylindrical portion, and has a cover portion that plugs the end portion, wherein the introduction pipe extends from a lower side to an upper side in the vertical direction to a position lower than the center of the first cylindrical portion in the vertical direction, wherein the introduction port is composed of a plurality of circular holes that penetrate the introduction pipe in a direction intersecting the vertical direction, and wherein the plurality of circular holes are located in a portion of an outer peripheral surface of the introduction pipe close to the end portion of the introduction pipe.

2. The oil separator for a compressor according to claim 1, wherein the plurality of circular holes are located in a portion of the outer peripheral surface of the introduction pipe close to the end portion of the introduction pipe.

3. The oil separator for a compressor according to claim 1 or 2, wherein the plurality of circular holes are located in a portion of the outer peripheral surface of the introduction pipe close to the end portion of the introduction pipe.

4. The oil separator for a compressor according to any one of claims 1 to 3, wherein the plurality of circular holes are located in a portion of the outer peripheral surface of the introduction pipe close to the end portion of the introduction pipe.

5. The oil separator for a compressor according to any one of claims 1 to 4, wherein the plurality of circular holes are located in a portion of the outer peripheral surface of the introduction pipe close to the end portion of the introduction pipe.

6. The oil separator for a compressor according to any one of claims 1 to 5, wherein the plurality of circular holes are located in a portion of the outer peripheral surface of the introduction pipe close to the end portion of the introduction pipe.

7. The oil separator for a compressor according to any one of claims 1 to 6, wherein the plurality of circular holes are located in a portion of the outer peripheral surface of the introduction pipe close to the end portion of the introduction pipe.

8. The oil separator for a compressor according to any one of claims 1 to 7, wherein the plurality of circular holes are located in a portion of the outer peripheral surface of the introduction pipe close to the end portion of the introduction pipe.

9. The oil separator for a compressor according to any one of claims 1 to 8, wherein the plurality of circular holes are located in a portion of the outer peripheral surface of the introduction pipe close to the end portion of the introduction pipe.

2. The oil separator for a compressor according to claim 1, wherein 10. The oil separator for a compressor according to any one of claims 1 to 9, wherein the plurality of circular holes are located in a portion of the outer peripheral surface of the introduction pipe close to the end portion of the introduction pipe.

3. The oil separator for a compressor according to claim 1, wherein ​ 4. The oil separator for a compressor according to claim 2, wherein ​ ​ 5. A compressor for a very low temperature refrigerator, wherein, ​

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