Screw compressors and gas compression equipment

Abstract

To provide a screw compressor and gas compression equipment that can effectively suppress gas leakage from the compression chamber to the bearing chamber. [Solution] The screw compressor comprises a screw rotor, a bearing for rotatably supporting the screw rotor, a casing for housing the screw rotor and the bearing, and a labyrinth seal ring provided between a compression chamber housing the screw rotor and a bearing chamber housing the bearing, wherein the labyrinth seal ring is held within the casing so as to be radially movable in accordance with the displacement of the axial center of the screw rotor.

Description

Technical Field

[0001] The present disclosure relates to a screw compressor and a gas compression facility.

Background Art

[0002] In a screw compressor, gas (compressed gas) may leak from the compression chamber to the bearing chamber due to the pressure difference between the compression chamber and the bearing chamber. The bearing chamber is connected to the compression chamber on the suction side. When gas leaks from the compression chamber to the bearing chamber as described above, the leaked gas expands and occupies the volume of the suction-side compression chamber, resulting in a decrease in suction efficiency. Alternatively, surplus power is generated because the leaked gas has to be recompressed. Thus, gas leakage from the compression chamber to the bearing chamber leads to a decrease in the efficiency of the compressor. Therefore, in order to reduce such gas leakage, a labyrinth structure is provided between the compression chamber and the bearing chamber.

[0003] Patent Document 1 describes an oil-cooled screw compressor provided with a rotor shaft to which a spacer having a labyrinth structure is attached. The spacer is provided so as to be located between the rotor chamber (compression chamber) and the bearing chamber, and the labyrinth groove provided on the outer peripheral surface of the spacer prevents the leakage of compressed gas from the rotor chamber to the bearing chamber.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in a screw compressor, when the axial center of the screw rotor is displaced due to a change in the rotational speed or the like, the gap between the rotor shaft and the casing expands in a region on the opposite side of the displacement direction of the axial center of the screw rotor with respect to the axial center, and gas leakage from the compression chamber to the bearing chamber is likely to occur.

[0006] In view of the above circumstances, at least one embodiment of the present invention aims to provide a screw compressor and gas compression equipment capable of effectively suppressing gas leakage from the compression chamber to the bearing chamber. [Means for solving the problem]

[0007] A screw compressor according to at least one embodiment of the present invention is Screw rotor and, A bearing for rotatably supporting the screw rotor, A casing for housing the screw rotor and the bearing, A labyrinth seal ring is provided between the compression chamber in which the screw rotor is housed and the bearing chamber in which the bearing is housed, Equipped with, The labyrinth seal ring is held within the casing so as to be radially movable in accordance with the displacement of the axis of the screw rotor.

[0008] Furthermore, a gas compression system according to at least one embodiment of the present invention is The screw compressor described above, configured to compress gas, An oil separator for separating the oil from the mixture of compressed gas and oil discharged from the screw compressor, An oil supply line for supplying the oil from the oil separator to the labyrinth seal ring, It is equipped with. [Effects of the Invention]

[0009] According to at least one embodiment of the present invention, a screw compressor and gas compression equipment are provided that can effectively suppress gas leakage from the compression chamber to the bearing chamber. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram of a gas compression system according to one embodiment. [Figure 2]This is a schematic cross-sectional view in plan view of a screw compressor according to one embodiment. [Figure 3] This is a schematic cross-sectional view showing an enlarged portion of a screw compressor including a labyrinth seal ring according to one embodiment. [Figure 4] This is a schematic cross-sectional view showing an enlarged portion of a screw compressor including a labyrinth seal ring according to one embodiment. [Modes for carrying out the invention]

[0011] Hereinafter, several embodiments of the present invention will be described with reference to the attached drawings. However, the dimensions, materials, shapes, relative arrangements, etc., of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples.

[0012] (Configuration of the gas compression equipment) Figure 1 is a schematic diagram of a gas compression system including a screw compressor according to several embodiments. As shown in the figure, the gas compression system 1 comprises a screw compressor 2, an oil separator 4, a cooler 6, and a pump 8.

[0013] The screw compressor 2 is configured to compress and discharge the inhaled gas. In the figure, the symbol Ps indicates the suction pressure of the screw compressor 2, and the symbol Pd indicates the discharge pressure of the screw compressor 2. The screw compressor 2 is supplied with oil via the oil supply line 10 for cooling and lubrication. The oil supplied to the screw compressor 2 is discharged together with the compressed gas.

[0014] The oil separator 4 is configured to separate oil from the mixture of compressed gas and oil discharged from the screw compressor 2. The oil separated by the oil separator 4 is supplied back to the screw compressor 2 via the oil supply line 10. Typically, the oil separated by the oil separator 4 is pressurized by the pump 8 and then supplied to the screw compressor 2 via the oil supply line 10. In this case, the pressure Poil of the oil supplied to the screw compressor 2 is higher than the discharge pressure Pd (Poil = Pd + α). Note that the oil separated by the oil separator 4 may be cooled by the cooler 6 and then pressurized by the pump 8. Also, the oil separated by the oil separator 4 may be cooled by the cooler 6 and then supplied to the screw compressor by differential pressure oil supply via the oil supply line 10' without passing through the pump 8.

[0015] (Configuration of Screw Compressor) FIG. 2 is a schematic cross-sectional view in a plan view of a screw compressor according to an embodiment. The screw compressor 2 shown in FIG. 2 is a twin screw compressor including a pair of screw rotors (male rotor 15 and female rotor 17) including a pair of rotor shafts 14, 16, and a casing 12 that houses the pair of screw rotors. In other embodiments, the screw compressor may be a single screw compressor including one screw rotor including a rotor shaft and a casing that houses the screw rotor.

[0016] The rotor shafts 14, 16 are rotatably supported by radial bearings 18A, 18B and thrust bearings 20, respectively. Oil at a pressure Poil is supplied to each bearing via the oil supply line 10. Each bearing is housed in a bearing chamber formed inside the casing 12. In the screw compressor 2 shown in FIG. 2, the pair of radial bearings 18B (the radial bearings on the discharge side) are each housed in the bearing chamber 19. Each bearing may be a rolling bearing or a sliding bearing.

[0017] The male rotor 15 and the female rotor 17 have helical teeth that mesh with each other. The meshing of the teeth of the male rotor 15 and the female rotor 17 and the casing 12 form a plurality of tooth groove spaces (chambers) along the axial direction of the rotor shafts 14, 16. The male rotor 15 and the female rotor 17 are accommodated in a compression chamber 13 formed inside the casing 12.

[0018] The rotor shaft 14 constituting the male rotor 15 is connected to the output shaft of a motor (not shown) and is configured to be rotationally driven by the motor. The female rotor 17 meshing with the male rotor 15 is rotationally driven by the rotation of the male rotor 15. The female rotor 17 rotates in a direction opposite to the rotation direction of the male rotor 15. When the male rotor 15 and the female rotor 17 rotate in a meshed state, the tooth groove space moves axially from the suction side toward the discharge side.

[0019] The oil supplied to the bearings and the shaft seal part (not shown) is discharged from the casing 12 and is returned to a relatively low-pressure space in the screw rotor accommodating part of the casing 12 via the return line 28. Note that the oil supply lines to the respective bearing parts and shaft seal parts branched from the oil supply line 10 and the return line 28 from each part may include external lines provided outside the casing 12 or may include internal lines provided inside the casing.

[0020] Gas is inhaled into the above-described tooth groove space from the suction space 50 formed in the casing 12 through the suction port 52. When the male rotor 15 and the female rotor 17 rotate, as these screw rotors rotate, the tooth groove space moves axially from the suction side toward the discharge side. In this process, since the volume of the tooth groove space decreases after the suction port 52 is closed, the gas in the tooth groove space is compressed. When the tooth groove space reaches the discharge port 54 and the tooth groove space communicates with a discharge space (not shown) formed in the casing 12, the compressed gas in the tooth groove space is discharged into the discharge space. Note that the discharge port 54 is formed by an opening provided in the end face of the casing 12.

[0021] In some embodiments, the screw compressor 2 includes a labyrinth seal ring 60 provided in the axial direction between the compression chamber 13 and the discharge-side bearing chamber. In the exemplary embodiment shown in Figure 2, a labyrinth seal ring 60 is provided between the compression chamber 13 and the bearing chamber 19 housing the discharge-side radial bearing 18B that supports the rotor shaft 14 of the male rotor 15, and also between the compression chamber 13 and the bearing chamber 19 housing the discharge-side radial bearing 18B that supports the rotor shaft 16 of the female rotor 17. These labyrinth seal rings 60 are held within the casing 12 so as to be radially movable in accordance with the displacement of the axial center of the screw rotor (male rotor 15 or female rotor 17) corresponding to the labyrinth seal ring 60.

[0022] Figures 3 and 4 are schematic cross-sectional views showing enlarged portions of a screw compressor 2, including the labyrinth seal ring 60, according to one embodiment. Although Figures 3 and 4 illustrate the labyrinth seal ring 60 provided between the rotor shaft 14 and the casing 12 of the male rotor 15, a similar configuration can be applied to the labyrinth seal ring 60 provided between the rotor shaft 16 and the casing 12 of the female rotor 17.

[0023] As shown in Figures 2 to 4, the labyrinth seal ring 60 includes an annular member provided on the outer circumference of the rotor shaft 14 and the inner circumference of the casing 12 in the radial direction of the rotor shaft 14. The labyrinth seal ring 60 is a separate component from the rotor and casing and can move independently of the rotor and casing. Gaps are formed between the inner surface of the labyrinth seal ring 60 and the outer surface of the rotor shaft 14 in the radial direction, and between the outer surface of the labyrinth seal ring 60 and the inner surface of the casing 12 in the radial direction. (Note that in Figures 3 and 4, the outer surface of the labyrinth seal ring 60 and the inner surface of the casing 12 are shown in contact, but in reality, a small gap is formed between them.)

[0024] The inner circumferential surface of the labyrinth seal ring 60 is provided with a plurality of annular protrusions (for example, the first annular protrusion 62 and the second annular protrusion 64 in Figures 3 and 4) that project radially inward, and the irregularities formed on the inner circumferential surface of the labyrinth seal ring 60 by the plurality of annular protrusions constitute a labyrinth structure. As a result, the fluid flow from the compression chamber 13 toward the bearing chamber 19 is reduced.

[0025] As shown in Figures 3 and 4, in some embodiments, the screw compressor 2 includes an adjacent member 72 provided adjacent to the labyrinth seal ring 60 in the axial direction. The adjacent member 72 is provided adjacent to the labyrinth seal ring 60 in the axial direction, on the opposite side of the compression chamber 13 from the labyrinth seal ring 60.

[0026] In the exemplary embodiments shown in Figures 3 and 4, the adjacent member 72 is an annular member provided axially between the radial bearing 18B (see Figure 2) and the labyrinth seal ring 60, and has a flange portion 72a projecting radially inward. In other embodiments, the adjacent member adjacent to the labyrinth seal ring 60 may include a bearing (the outer ring or housing of the bearing).

[0027] In some embodiments, the screw compressor 2 includes a pin 76 fixed to either the labyrinth seal ring 60 or an adjacent member 72, and a notch 74 provided on the other of the labyrinth seal ring 60 or adjacent member 72 (i.e., the one of the labyrinth seal ring 60 or adjacent member 72 to which the pin 76 is not fixed), which accommodates a portion of the pin 76. The pin 76 is provided such that its central axis is aligned with the axial direction of the rotor shaft 14. The size (length) D2 of the notch 74 in the radial direction of the rotor shaft 14 is greater than the diameter D1 of the pin 76.

[0028] In the exemplary embodiment shown in Figure 3, the screw compressor 2 includes a pin 76 fixed to a labyrinth seal ring 60 and a notch 74 provided in an adjacent member 72. The pin 76 is partially inserted into a hole 61 provided in the labyrinth seal ring 60 and is fixed to the labyrinth seal ring 60 by means of interference fit, screw fastening, etc. The notch 74 is provided so as to be recessed radially outward from the inner circumferential surface of the adjacent member 72. The exposed portion of the pin 76 (the portion not inserted into the hole 61) is accommodated in the notch 74 of the adjacent member 72.

[0029] In the exemplary embodiment shown in Figure 4, the screw compressor 2 includes a pin 76 fixed to an adjacent member 72 and a notch 74 provided in the labyrinth seal ring 60. The pin 76 is partially inserted into a hole 73 provided in the adjacent member 72 and is fixed to the adjacent member 72 by means of interference fit, screw fastening, etc. The notch 74 is provided so as to be recessed radially inward from the outer circumferential surface of the labyrinth seal ring 60. The exposed portion of the pin 76 (the portion not inserted into the hole 73) is housed in the notch 74 of the labyrinth seal ring 60.

[0030] In a screw compressor, if gas leaks from the compression chamber to the bearing chamber due to the pressure difference between the compression chamber and the bearing chamber, the efficiency of the compressor decreases because the volume of the compression space decreases due to the expansion of the leaked gas as it flows into the intake side of the compression chamber along with the discharge of the oil supplied to the bearing chamber, and compression of gas that does not contribute to the gas cycle (re-compression of leaked gas) occurs. Here, if a labyrinth seal is installed between the compression chamber and the bearing chamber of the screw compressor, gas leakage can be suppressed by narrowing the clearance of the labyrinth seal (the gap between the rotor shaft side and the casing side). On the other hand, if the labyrinth seal is fixed to the rotor shaft or casing, the labyrinth seal and the casing or rotor shaft are more likely to come into contact when the rotor shaft is displaced.

[0031] In this regard, in the above-described configuration, the labyrinth seal ring 60 is held within the casing 12 so as to be able to move radially in accordance with the displacement of the axis of the screw rotor (male rotor 15, etc.). More specifically, as described above, for example, the radial size D2 of the notch 74 provided on the other side of the labyrinth seal ring 60 or the adjacent member 72 is larger than the diameter D1 of the pin 76 fixed to one of the labyrinth seal ring 60 or the adjacent member 72. Therefore, with a portion of the pin 76 housed in the notch 74, the labyrinth seal ring 60 is able to move radially between the rotor shaft 14 and the casing 12. Thus, since the labyrinth seal ring 60 can move radially in accordance with the displacement of the axis of the screw rotor (male rotor 15), the gap can be kept narrow even if the axis of the screw rotor is displaced. Therefore, while suppressing contact between the rotor shaft 14 and the labyrinth seal, leakage of gas from the compression chamber 13 to the bearing chamber 19 can be effectively suppressed.

[0032] In some embodiments, the pin 76 may serve as an anti-rotation mechanism for the labyrinth seal ring 60. For this reason, the circumferential width of the notch 74, which accommodates a portion of the pin 76, may be slightly larger than the diameter D1 of the pin 76.

[0033] Furthermore, the size D2 of the radial notch 74 may be larger than the circumferential width of the notch 74. This allows for moderate restriction of the circumferential movement of the labyrinth seal ring 60 while facilitating its radial movement.

[0034] In some embodiments, the adjacent member 72 is provided to restrict the axial movement of the labyrinth seal ring 60.

[0035] For example, the adjacent member 72 may receive an axial force from the outer ring of the radial bearing 18B (see Figure 2) directed toward the intake side, thereby pressing the adjacent member 72 against the casing 12 in the axial direction, and determining the position of the adjacent member 72 relative to the casing 12 in the axial direction. Furthermore, as shown in Figures 3 and 4, for example, the labyrinth seal ring 60 may be housed in an annular space surrounded by the casing 12, the flange portion 72a of the adjacent member 72, and the rotor shaft 14. The radial bearing 18B may be fixed to the casing 12 by a bolt (not shown) whose central axis is aligned with the axial direction of the rotor shaft 14. The axial force acting on the adjacent member 72 from the outer ring of the radial bearing 18B may be the axial force of the bolt.

[0036] In some embodiments, the plurality of annular protrusions provided on the inner circumferential surface of the labyrinth seal ring 60 include at least one first annular protrusion 62 provided on the compression chamber 13 side in the axial direction, at least one second annular protrusion 64 provided on the bearing chamber 19 side in the axial direction, and an oil pocket 66 located between the at least one first annular protrusion 62 and the at least one second annular protrusion 64 in the axial direction. Oil is supplied to the oil pocket 66.

[0037] By supplying oil to the oil pocket 66, oil is retained in the labyrinth formed by the first annular protrusion 62 and the second annular protrusion 64, thereby obstructing the flow of gas from the compression chamber 13 to the bearing chamber 19. Therefore, gas leakage from the compression chamber 13 to the bearing chamber 19 can be suppressed more effectively.

[0038] In some embodiments, the number of second annular protrusions 64 is greater than the number of first annular protrusions 62. In the exemplary embodiments shown in Figures 3 and 4, the labyrinth seal ring 60 includes two first annular protrusions 62 and four second annular protrusions 64. That is, the number of second annular protrusions 64 is greater than the number of first annular protrusions 62.

[0039] When oil at a pressure approximately equal to the discharge pressure of the screw compressor 2 is supplied to the oil pocket 66, the pressure difference between the oil pocket 66 and the bearing chamber 19 tends to be greater than the pressure difference between the oil pocket 66 and the compression chamber 13. As described above, by increasing the number of second annular protrusions 64 on the bearing chamber 19 side, where the pressure difference with the oil pocket 66 is relatively large, to more than the number of first annular protrusions 62 on the compression chamber 13 side, the outflow of oil from the oil pocket 66 can be effectively suppressed.

[0040] In some embodiments, oil discharged from the screw compressor 2 along with the compressed gas may be supplied to the oil pocket 66. For example, oil (pressure: Poil) from an oil separator 4 (see Figure 1), into which oil discharged from the screw compressor 2 along with the compressed gas is led, may be supplied to the oil pocket 66 of the labyrinth seal ring 60 via an oil supply line 10 (see Figure 2). As shown in Figures 2 to 4, the oil from the oil supply line 10 may be supplied to the oil pocket 66 via an internal passage 80 provided in the casing 12.

[0041] As shown in Figures 3 and 4, in some embodiments, the labyrinth seal ring 60 may include an oil passage 68 that is recessed radially inward from the outer circumferential surface of the labyrinth seal ring 60, and a connecting passage 70 that connects the oil passage 68 to the oil pocket 66. Oil from the oil supply line 10 may be supplied to the oil pocket 66 via the internal passage 80, the oil passage 68, and the connecting passage 70.

[0042] The oil passage 68 may be an annular groove extending along the circumferential direction of the rotor shaft 14. The connecting passage 70 may be provided to extend along the radial direction of the rotor shaft 14. The labyrinth seal ring 60 may also include a plurality of connecting passages 70 provided to be spaced apart in the circumferential direction.

[0043] As shown in Figures 3 and 4, the screw compressor 2 may be equipped with an O-ring 78 provided between the casing 12 and the labyrinth seal ring 60 in the axial direction.

[0044] In some embodiments, for example, as shown in Figures 3 and 4, the adjacent member 72, the labyrinth seal ring 60, and the O-ring 78 may be arranged in this order in the axial direction. With this arrangement, the labyrinth seal ring 60, which is being pushed toward the bearing chamber side by the restoring force of the O-ring 78, can be properly received by the adjacent member 72.

[0045] In some embodiments, as shown in Figures 3 and 4, for example, the O-ring 78 is provided radially outward from the radial inner end 68a (or bottom surface) of the oil passage 68.

[0046] Since the oil passage 68 is supplied with oil at a higher pressure (pressure: Poil) than the compression chamber 13 and bearing chamber 19, an axial force acts on the labyrinth seal ring 60 in accordance with the pressure difference at the pressure-receiving portion (the axial end faces 60a, 60b of the labyrinth seal ring 60 and the side wall faces 69a, 69b of the oil passage 68). In this respect, with the above configuration, since the O-ring 78 is provided radially outward from the inner end 68a of the oil passage 68 in the radial direction, the force acting on the labyrinth seal ring 60 in the axial direction toward the compression chamber 13, based on the pressure difference between the axial end face 60a of the labyrinth seal ring 60 (the axial end face on the compression chamber 13 side) and the side wall face 69a of the oil passage 68 that face the casing 12, can be increased to a certain extent. This reduces the opposing axial force acting on the labyrinth seal ring 60 (force from the labyrinth seal ring 60 toward the bearing chamber 19; force arising from the pressure difference between the axial end face 60b of the labyrinth seal ring 60 facing the adjacent member 72 (the axial end face on the bearing chamber 19 side) and the side wall surface 69b of the oil passage 68). In other words, it is possible to suppress excessive force pressing the labyrinth seal ring 60 toward the adjacent member 72. Therefore, improper axial movement of the components of the screw compressor (such as bearing components) becomes less likely.

[0047] In some embodiments, as shown in Figure 2, for example, the screw compressor 2 is equipped with a pair of labyrinth seal rings 60 corresponding to a pair of screw rotors (male rotor 15 and female rotor 17), and each of the pair of labyrinth seal rings 60 is provided with an annular oil passage 68 (see Figures 3 and 4). In addition, an internal passage 82 is formed in the casing 12 that connects the oil passage 68 on the male rotor 15 side and the oil passage 68 on the female rotor 17 side.

[0048] According to the above embodiment, since an internal passage 82 is provided in the casing 12 that connects the oil passages 68 of a pair of labyrinth seal rings 60, by supplying oil to the oil passage 68 of one labyrinth seal ring 60 (the labyrinth seal ring 60 on the male rotor 15 side in Figure 2) from outside the casing 12, oil can also be supplied to the oil passage 68 of the other labyrinth seal ring 60 (the labyrinth seal ring 60 on the female rotor 17 side in Figure 2). In other words, with the above configuration, oil can be supplied to both of the pair of labyrinth seal rings 60 with a simple configuration.

[0049] In some embodiments, oil from the oil supply line 10 may be supplied to the oil passages 68 of the labyrinth seal ring 60 on the male rotor 15 side and the labyrinth seal ring 60 on the female rotor 17 side, respectively, via separate internal passages formed in the casing 12.

[0050] The contents described in each of the above embodiments can be understood, for example, as follows:

[0051] [1] A screw compressor (2) according to at least one embodiment of the present invention is A screw rotor (for example, male rotor 15 or female rotor 17), A bearing (e.g., radial bearing 18B) for rotatably supporting the screw rotor, A casing (12) for housing the screw rotor and the bearing, A labyrinth seal ring (60) is provided between the compression chamber (13) in which the screw rotor is housed and the bearing chamber (19) in which the bearing is housed, Equipped with, The labyrinth seal ring is held within the casing so as to be radially movable in accordance with the displacement of the axis of the screw rotor.

[0052] When a labyrinth seal is installed between the compression chamber and the bearing chamber of a screw compressor, narrowing the clearance of the labyrinth seal (the gap between the rotor shaft side and the casing side) can suppress gas leakage. On the other hand, if the labyrinth seal is fixed to the rotor shaft or casing, the labyrinth seal and the casing or rotor shaft are more likely to come into contact when the rotor shaft is displaced. According to the configuration in [1] above, the labyrinth seal ring is movable radially in accordance with the displacement of the axis of the screw rotor, so the gap can be kept narrow even if the axis of the screw rotor is displaced due to changes in rotational speed, etc. Therefore, it is possible to effectively suppress gas leakage from the compression chamber to the bearing chamber while suppressing contact between the rotor shaft and the labyrinth seal.

[0053] [2] In some embodiments, in the configuration of [1] above, The labyrinth seal ring is At least one first annular projection (62) provided on the compression chamber side, The bearing chamber side has at least one second annular projection (64), An oil pocket (66) located in the axial direction between the at least one first annular protrusion and the at least one second annular protrusion, Includes.

[0054] According to the configuration described in [2] above, the labyrinth seal ring is provided with a first annular projection and a second annular projection, and an oil pocket located between the first annular projection and the second annular projection. By supplying oil to the oil pocket, oil is retained in the labyrinth formed by the first annular projection and the second annular projection. This obstructs the flow of gas from the compression chamber to the bearing chamber, and thus more effectively suppresses gas leakage from the compression chamber to the bearing chamber.

[0055] [3] In some embodiments, in the configuration of [2] above, The number of at least one second annular protrusion is greater than the number of at least one first annular protrusion.

[0056] When oil at a pressure similar to the compressor's discharge pressure is supplied to the oil pocket, the pressure difference between the oil pocket and the bearing chamber tends to be greater than the pressure difference between the oil pocket and the compression chamber. According to the configuration described in [3] above, the number of second annular protrusions on the bearing chamber side, where the pressure difference with the oil pocket is relatively large, is greater than the number of first annular protrusions on the compression chamber side, so the outflow of oil from the oil pocket can be effectively suppressed.

[0057] [4] In some embodiments, in the configuration of [2] or [3] above, The screw compressor is, The system is configured such that oil discharged from the screw compressor along with compressed gas is supplied to the oil pocket.

[0058] According to the configuration described in [4] above, high-pressure oil discharged into the oil pocket along with the compressed gas is supplied to the oil pocket, so the oil is more easily retained in the labyrinth formed by the first and second annular protrusions. Therefore, the flow of gas from the compression chamber to the bearing chamber can be more effectively inhibited, and thus gas leakage from the compression chamber to the bearing chamber can be more effectively suppressed.

[0059] [5] In some embodiments, in any of the configurations described in [1] to [4] above, The screw compressor is, A pin (76) fixed to the labyrinth seal ring or to one of the adjacent members adjacent to the labyrinth seal ring in the axial direction, A notch (74) is provided on the labyrinth seal ring or the other adjacent member, and a portion of the pin is accommodated therein. Equipped with, The size of the notch in the radial direction (D2) is greater than the diameter of the pin (D1).

[0060] According to the configuration described in [5] above, the radial size of the notch provided in the other of the labyrinth seal ring or adjacent member is larger than the diameter of the pin fixed to the labyrinth seal ring or adjacent member. Therefore, with a portion of the pin housed in the notch, the labyrinth seal ring can move radially between the rotor and the casing. Thus, as described in [1] above, the labyrinth seal ring can move radially in accordance with the displacement of the axis of the screw rotor, so that the gap can be kept narrow even if the axis of the screw rotor is displaced. Therefore, while suppressing contact between the rotor shaft and the labyrinth seal, gas leakage from the compression chamber to the bearing chamber can be effectively suppressed.

[0061] [6] In some embodiments, in the configuration of [5] above, The size of the notch in the circumferential direction is larger than the diameter of the pin.

[0062] According to the configuration described in [6] above, the circumferential size of the notch provided on the other side of the labyrinth seal ring or adjacent member is larger than the diameter of the pin fixed to the labyrinth seal ring or adjacent member. As a result, the labyrinth seal ring can move circumferentially between the rotor and the casing with a portion of the pin housed in the notch. Therefore, the labyrinth seal ring can move radially and circumferentially in accordance with the displacement of the screw rotor's axis. This allows the gap to be kept narrow even if the screw rotor's axis is displaced, by allowing the labyrinth seal ring to move in accordance with the rotor axis. Thus, gas leakage from the compression chamber to the bearing chamber can be more effectively suppressed while preventing contact between the rotor axis and the labyrinth seal.

[0063] [7] In some embodiments, in any of the configurations described in [1] to [6] above, The screw compressor is, An adjacent member (72) is provided adjacent to the labyrinth seal ring in the axial direction and to restrict the position of the labyrinth seal ring in the axial direction, An O-ring (78) is provided between the casing and the labyrinth seal ring in the axial direction, Equipped with, The adjacent member, the labyrinth seal ring, and the O-ring are arranged in this order in the axial direction.

[0064] According to the configuration described in [7] above, the adjacent member, the labyrinth seal ring, and the O-ring are arranged in this order in the axial direction, so that the labyrinth seal ring 60, which is being pushed toward the bearing chamber side by the restoring force of the O-ring 78, can be properly received by the adjacent member 72.

[0065] [8] In some embodiments, in the configuration of [2] above, The screw compressor is, An O-ring (78) is provided between the casing and the labyrinth seal ring in the axial direction, The labyrinth seal ring is An oil passage (68) is provided so as to be recessed from the outer surface of the labyrinth seal ring, through which oil for supplying to the oil pocket is guided, A connecting passage (70) that connects the oil passage and the oil pocket, Includes, The O-ring is provided radially outward from the inner end (68a) of the oil passage in the radial direction.

[0066] According to the configuration described in [8] above, since the O-ring is provided radially outward from the inner end of the oil passage in the radial direction, the force acting on the labyrinth seal ring 60 in the axial direction toward the compression chamber 13 can be increased to some extent based on the difference in pressure acting on the axial end face of the labyrinth seal ring (the face facing the casing) and the side wall surface of the oil passage. This reduces the opposing force acting on the labyrinth seal ring 60 in the axial direction (the force toward the bearing chamber 19 from the labyrinth seal ring 60; the force generated based on the difference in pressure acting on the axial end face 60b of the labyrinth seal ring 60 facing the adjacent member 72 (the axial end face on the bearing chamber 19 side) and the side wall surface 69b of the oil passage 68). In other words, it is possible to suppress the force pressing the labyrinth seal ring 60 toward the adjacent member 72 from becoming excessive. Therefore, inappropriate axial movement of the components of the screw compressor (such as bearing components) becomes less likely.

[0067] [9] In some embodiments, in any of the configurations described in [1] to [8] above, The screw compressor is, A pair of screw rotors (male rotor 15 and female rotor 17), A pair of bearings for rotatably supporting each of the pair of screw rotors, A pair of labyrinth seal rings are provided between the compression chamber in which the pair of screw rotors are housed and the pair of bearing chambers in which the pair of bearings are housed, Equipped with, The casing is configured to house the pair of screw rotors and the pair of bearings, Each of the pair of labyrinth seal rings includes an annular oil passage recessed from the outer surface of the labyrinth seal ring, The screw compressor is, The casing is provided with an internal passage (82) that connects the oil passage of one of the pair of labyrinth seal rings to the oil passage of the other of the pair of labyrinth seal rings.

[0068] According to the configuration described in [9] above, an internal passage is provided in the casing that connects the oil passages of a pair of labyrinth seal rings. Therefore, by supplying oil to the oil passage of one labyrinth seal ring from outside the casing, oil can also be supplied to the oil passage of the other labyrinth seal ring. In other words, according to the configuration described in [9] above, oil can be supplied to both of a pair of labyrinth seal rings with a simple configuration.

[0069]

[10] A gas compression apparatus (1) according to at least one embodiment of the present invention is A screw compressor (2) as described in any one of the above [1] to [9], configured to compress gas, An oil separator (4) for separating the oil from the mixture of compressed gas and oil discharged from the screw compressor, An oil supply line (10) for supplying the oil from the oil separator to the labyrinth seal ring, It is equipped with.

[0070] According to the configuration described in

[10] above, the labyrinth seal ring is movable radially in accordance with the displacement of the screw rotor's axis, so that the gap can be kept narrow even if the screw rotor's axis is displaced due to changes in rotational speed, etc. Therefore, it is possible to effectively suppress gas leakage from the compression chamber to the bearing chamber while suppressing contact between the rotor shaft and the labyrinth seal. Furthermore, according to the configuration described in

[10] above, the high-pressure oil discharged together with the compressed gas is supplied to the labyrinth seal ring, so the oil is easily retained in the labyrinth of the labyrinth seal ring, and for this reason, the flow of gas from the compression chamber to the bearing chamber can be effectively obstructed. Thus, gas leakage from the compression chamber to the bearing chamber can be suppressed more effectively.

[0071] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and also includes modified forms of the embodiments described above, as well as forms that combine these forms as appropriate.

[0072] In this specification, expressions describing relative or absolute arrangements such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" shall not only describe such arrangements strictly, but also describe states of relative displacement with tolerances or angles or distances that allow for the same function to be achieved. For example, expressions such as "identical," "equal," and "homogeneous" that describe things being in an equal state not only describe a state of being strictly equal, but also describe a state in which there is a tolerance or a difference that is sufficient to achieve the same function. Furthermore, in this specification, expressions describing shapes such as quadrilaterals and cylindrical shapes shall not only represent geometrically precise quadrilaterals and cylindrical shapes, but also shapes that include uneven surfaces, chamfered surfaces, etc., to the extent that the same effect can be achieved. Furthermore, in this specification, the expressions “equipment,” “includes,” or “possess” of a component are not exclusive expressions that exclude the existence of other components. [Explanation of Symbols]

[0073] 1. Gas compression equipment 2 Screw compressor 4 Oil separator 6 Cooler 8 pumps 10,10' Oil supply line 12 Casing 13 Compression Chamber 14 Rotor shaft 15 Male rotor 16 rotor shaft 17 Female rotor 18A, 18B radial bearings 19. Bearing chamber 20 Thrust bearings 28 Return Line 50 Suction space 52 Inhalation Ports 54 Discharge Ports 60 Labyrinth Seal Rings 60a,60b Axial end face 61 holes 62 First ring-shaped protrusion 64 Second ring-shaped protrusion 66 Oil pocket 68 Oil passage 68a Inner end 69a, 69b Side wall 70 Communication path 72 Adjacent members 72a Flange section 73 holes 74 Notches 76 pins 78 O-rings 80 Internal passage 82 Internal passage

Claims

1. Screw rotor and, A bearing for rotatably supporting the screw rotor, A casing for housing the screw rotor and the bearing, A labyrinth seal ring is provided between the compression chamber in which the screw rotor is housed and the bearing chamber in which the bearing is housed, Equipped with, The labyrinth seal ring is held within the casing so as to be radially movable in accordance with the displacement of the axis of the screw rotor. Screw compressor.

2. The labyrinth seal ring is At least one first annular projection provided on the compression chamber side, At least one second annular projection provided on the bearing chamber side, An oil pocket located in the axial direction between the at least one first annular protrusion and the at least one second annular protrusion, including The screw compressor according to claim 1.

3. The number of at least one second annular protrusion is greater than the number of at least one first annular protrusion. The screw compressor according to claim 2.

4. The oil discharged from the screw compressor along with the compressed gas is supplied to the oil pocket. The screw compressor according to claim 2 or 3.

5. A pin fixed to the labyrinth seal ring or to one of the adjacent members adjacent to the labyrinth seal ring in the axial direction, A notch is provided on the labyrinth seal ring or the other adjacent member, in which a portion of the pin is accommodated, Equipped with, The size of the notch in the radial direction is larger than the diameter of the pin. A screw compressor according to any one of claims 1 to 3.

6. The size of the notch in the circumferential direction is larger than the diameter of the pin. The screw compressor according to claim 5.

7. An adjacent member is provided adjacent to the labyrinth seal ring in the axial direction and to restrict the position of the labyrinth seal ring in the axial direction, An O-ring is provided between the casing and the labyrinth seal ring in the axial direction, Equipped with, The adjacent member, the labyrinth seal ring, and the O-ring are arranged in this order in the axial direction. A screw compressor according to any one of claims 1 to 3.

8. An O-ring is provided between the casing and the labyrinth seal ring in the axial direction, The labyrinth seal ring is An oil passage is provided so as to be recessed from the outer circumferential surface of the labyrinth seal ring, through which oil for supplying the oil pocket is guided, A connecting passage that connects the oil passage and the oil pocket, Includes, The O-ring is provided radially outward from the radial inner end of the oil passage. The screw compressor according to claim 2.

9. A pair of screw rotors, A pair of bearings for rotatably supporting each of the pair of screw rotors, A pair of labyrinth seal rings are provided between the compression chamber in which the pair of screw rotors are housed and the pair of bearing chambers in which the pair of bearings are housed, Equipped with, The casing is configured to house the pair of screw rotors and the pair of bearings, Each of the pair of labyrinth seal rings includes an annular oil passage recessed from the outer surface of the labyrinth seal ring, The casing is provided with an internal passage that connects the oil passage of one of the pair of labyrinth seal rings to the oil passage of the other of the pair of labyrinth seal rings. A screw compressor according to any one of claims 1 to 3.

10. A screw compressor according to any one of claims 1 to 3, configured to compress gas, An oil separator for separating the oil from the mixture of compressed gas and oil discharged from the screw compressor, An oil supply line for supplying the oil from the oil separator to the labyrinth seal ring, A gas compression system equipped with the following features.

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