Liquid-cooled screw compressor

Abstract

To provide a liquid-cooled screw compressor that is excellent in processability and maintainability and can improve cooling performance to a gas in a workspace.SOLUTION: A liquid-cooled screw compressor 100 for sucking a gas to generate a compressed gas includes: screw rotors 2, 3; a casing 1 accommodating the screw rotors 2, 3 and forming a workspace C together with the screw rotors 2, 3; and a cartridge 6 that is a separate member from the casing 1. The casing 1 and an outside surface of the cartridge 6 form a supply liquid route 7 for supplying liquid to the workspace C.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a liquid-cooled screw compressor. [Background technology]

[0002] A liquid-cooled screw compressor is known that includes a screw rotor and a casing that houses the screw rotor and forms a working space together with the screw rotor, and that cools gas within the working space by supplying liquid into the working space. Note that the liquid supplied into the working space is used not only for cooling but also to seal internal gaps that occur between the screw rotor and the casing and to lubricate sliding parts.

[0003] Patent Document 1 proposes a technique for atomizing liquid by causing liquids supplied to a working space to collide with each other, with the aim of improving the performance of a compressor.

[0004] In the compressor described in Patent Document 1, a fuel supply nozzle insertion hole is provided in the casing, and a fuel supply nozzle having multiple fuel supply paths for impinging jets inside is inserted into the fuel supply nozzle insertion hole. The fuel supply paths are made up of a main fuel supply path and small-diameter auxiliary fuel supply paths branching from the main fuel supply path and arranged in a V-shape. In the compressor described in Patent Document 1, the fuel supply nozzle is detachable, making it easier to maintain than when the fuel supply paths for impinging jets are directly machined into the casing. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-35782 Summary of the Invention [Problem to be solved by the invention]

[0006] Patent Document 1 discloses a fuel supply nozzle in which multiple fuel supply paths are formed in order to supply more liquid into the working space and improve cooling efficiency (see FIG. 9 of Patent Document 1). However, with this fuel supply nozzle, multiple fuel supply paths, each consisting of a main fuel supply path and auxiliary fuel supply paths arranged in a V-shape, must be formed inside the fuel supply nozzle, which requires time-consuming machining and raises concerns about increased machining costs.

[0007] An object of the present invention is to provide a liquid-cooled screw compressor that is easy to process and maintain and that can improve the cooling performance for gas in the working space. [Means for solving the problem]

[0008] A liquid-cooled screw compressor according to one aspect of the present invention is a liquid-cooled screw compressor that sucks in gas to generate compressed gas, and comprises a screw rotor, a casing that houses the screw rotor and forms an operating space together with the screw rotor, and a cartridge that is a separate member from the casing, and the casing and the outer surface of the cartridge form a liquid supply path that supplies liquid to the operating space. The casing has a storage chamber that stores the screw rotor, an inlet passage through which liquid is introduced from outside the casing, and a communication passage that connects the storage chamber and the inlet passage.When the cartridge is placed in the communication passage, at least one pair of ejection flow passages are formed by the tip of the cartridge and the inner surface of the communication passage, and liquids ejected from the at least one pair of ejection flow passages collide with each other within the operating space. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a liquid-cooled screw compressor that is easy to process and maintain and that can improve the cooling performance for the gas in the working space. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a plan cross-sectional view of a liquid-cooled screw compressor according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 3 is an enlarged cross-sectional view of part III in FIG. [Figure 4]FIG. 4 is a perspective view of the cartridge according to the first embodiment. [Figure 5] FIG. 5 is a diagram showing the results of a numerical analysis of the liquid ejected from the ejection flow path formed by the cartridge according to the first embodiment. [Figure 6] FIG. 6 is a plan cross-sectional view of a liquid-cooled screw compressor according to a comparative example of this embodiment. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8] FIG. 8 is a perspective view of a cartridge according to the second embodiment. [Figure 9] FIG. 9 is a diagram showing the results of a numerical analysis of the liquid ejected from the ejection flow path formed by the cartridge according to the second embodiment. [Figure 10] FIG. 10 is a perspective view of a cartridge according to the third embodiment. [Figure 11] FIG. 11 is a plan view of the cartridge of FIG. 10 as viewed from the direction XI. [Figure 12] FIG. 12 is a diagram showing the results of a numerical analysis of the liquid ejected from the ejection flow path formed by the cartridge according to the third embodiment. [Figure 13] FIG. 13 is a perspective view of a cartridge according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0012] First Embodiment A liquid-cooled screw compressor (hereinafter also referred to as compressor) 100 according to a first embodiment of the present invention will be described with reference to Figs. 1 to 5. Fig. 1 is a plan sectional view of the compressor 100. Fig. 2 is a sectional view taken along line II-II in Fig. 1. As shown in Figs. 1 and 2, the compressor 100 includes a drive rotor 2 and a driven rotor 3 as a pair of screw rotors that rotate while meshing with each other, and a casing 1 that rotatably houses the drive rotor 2 and the driven rotor 3 inside. The compressor 100 rotates the screw rotors 2 and 3 to suck in air (gas) and generate compressed air (compressed gas).

[0013] The drive rotor (male rotor) 2 has a plurality of spiral male teeth formed thereon. The driven rotor (female rotor) 3 has a plurality of spiral female teeth formed thereon. The casing 1 has a bore 8 as a storage chamber for storing the drive rotor 2 and driven rotor 3 in a meshed state, an intake port for drawing in air, and a discharge port for discharging compressed air. The pair of screw rotors 2, 3 and the inner wall surface of the bore 8 form a plurality of working spaces (working chambers) C for compressing air.

[0014] A prime mover such as an electric motor is connected to the drive rotor 2. When the drive rotor 2 begins to rotate due to the prime mover, the driven rotor 3, which is meshed with the drive rotor 2, also begins to rotate. This causes air to be drawn into the working space C from the suction port. As the screw rotors 2 and 3 rotate, the working space C moves from the suction port side to the discharge port side, and as it moves, its volume decreases. As the volume of the working space C decreases, the air moves toward the discharge port side while being compressed, and is then discharged from the discharge port to the outside of the compressor 100.

[0015] In the liquid-cooled screw compressor 100, in order to suppress a rise in the temperature of the air due to heat generated during the production of compressed air, a cooling liquid (for example, oil or water) is injected into the working space C. The cooling liquid injected into the working space C is used not only to cool the air in the working space C, but also to seal gaps between the screw rotors 2, 3 and the inner wall surface of the bore 8 and gaps in the meshing portions of the drive rotor 2 and driven rotor 3, and to lubricate the sliding portions of the screw rotors 2, 3.

[0016] 2, the compressor 100 is formed with a liquid supply path 7 that supplies liquid to the working space C. The liquid supply path 7 is provided on both the drive rotor 2 side and the driven rotor 3 side, but since the configuration is the same on both sides, only one side will be described below.

[0017] The casing 1 has an introduction passage 9 through which liquid is introduced from outside the casing 1, a communication passage 10 that connects the storage chamber 8 with the introduction passage 9, and an elongated hole 5 that connects the communication passage 10 with the storage chamber 8. As shown in FIGS. 1 and 2, the elongated hole 5 is an opening extending along the rotational axis direction of the screw rotors 2 and 3 (hereinafter also simply referred to as the axial direction). In other words, the elongated hole 5 is an opening surface located at the boundary between the communication passage 10 and the storage chamber 8, and is formed in a rectangular shape with the axial direction of the screw rotors 2 and 3 as its longitudinal direction and a direction perpendicular to the axial direction (horizontal direction) as its transverse direction. The elongated hole 5 according to this embodiment has a pair of opposing long sides and a pair of semicircular arcs connecting the pair of long sides at both ends. The elongated hole 5 is formed in each of the male bores 8 that house the drive rotor 2 and the female bores 8 that house the driven rotor 3.

[0018] The communicating passage 10 forms a space in the shape of a flattened rectangular parallelepiped, and by arranging the cartridge 6 in the communicating passage 10, a pair of liquid supply paths 7 are formed by the inner wall surface of the casing 1 and the outer surface of the cartridge 6. The cartridge 6 is detachable from the casing 1.

[0019] The configuration of the liquid supply path 7 will be described in detail with reference to FIGS. 3 and 4. FIG. 3 is an enlarged cross-sectional view of part III in FIG. 2, and FIG. 4 is a perspective view of the cartridge 6. As shown in FIGS. 3 and 4, the cartridge 6 is rectangular and flat, and has a pair of wide surface portions 62 facing each other and a pair of narrow surface portions 64 facing each other. The wide surface portions 62 and the narrow surface portions 64 are planar and perpendicular to each other. The pair of wide surface portions 62 are parallel to each other, and the pair of narrow surface portions 64 are parallel to each other. When the cartridge 6 is placed in the communicating passage 10, the base end portion 69 (see FIG. 4) is located on the introduction passage 9 side, and the tip end portion 61 is located on the bore 8 side. In other words, the cartridge 6 extends vertically within the communicating passage 10 from the introduction passage 9 side toward the bore 8 side. The area of ​​the wide surface portion 62 is larger than the area of ​​the base end surface (lower end surface) and the narrow surface portion 64 of the cartridge 6, respectively. The base end surface of the cartridge 6 is a plane that is perpendicular to both the wide surface portion 62 and the narrow surface portion 64 .

[0020] The cartridge 6 is formed with a through hole 66 that penetrates from one wide surface portion 62 to the other wide surface portion 62. The cross-sectional shapes of the through hole 66 and the introduction passage 9 (see FIG. 2) extending horizontally are circular. The opening area of ​​the through hole 66 is preferably equal to or larger than the flow path cross-sectional area of ​​the introduction passage 9. In other words, the diameter of the through hole 66 is preferably the same as or larger than the diameter of the introduction passage 9. The cartridge 6 is disposed in the communicating passage 10 so that the central axis of the through hole 66 coincides with the central axis of the introduction passage 9. As a result, when viewed from the thickness direction of the cartridge 6, the entire inner circumferential surface of the introduction passage 9 is disposed within the through hole 66.

[0021] The tip portion 61 of the cartridge 6 is formed in a tapered shape having a pair of tapered surface portions 63. That is, the thickness (the distance between the pair of tapered surface portions 63) of the tip portion 61 decreases toward the tip (the apex 6t) of the tip portion 61. A groove (recess) 65 is formed in the tapered surface portion 63 from the upper end of the wide surface portion 62 toward the apex 6t of the cartridge 6. The apex 6t is a flat surface parallel to the base end surface of the cartridge 6. The groove 65 is formed between axial end portions 63a at both axial ends of the tapered surface portion 63. A bottom surface (hereinafter also referred to as a tapered surface) 65a of the groove 65 is flat and inclined relative to the wide surface portion 62 so that the distance between the pair of tapered surfaces 65a decreases toward the apex 6t from the wide surface portion 62. The pair of tapered surfaces 65a are connected to each other by the apex 6t of the cartridge 6.

[0022] 3, the communicating passage 10 is formed with a pair of inclined surface portions 10a facing the pair of tapered surface portions 63 of the cartridge 6, a pair of first flow path walls 10b facing the pair of wide surface portions 62, and a pair of second flow path walls (not shown) facing the pair of narrow surface portions 64. In this embodiment, a step portion 10c is formed between the tapered surface portions 63 and the first flow path walls 10b, but the step portion 10c may be omitted. In other words, the tapered surface portions 63 and the first flow path walls 10b may be directly connected.

[0023] The communicating passage 10 is formed, for example, by protruding a V-shaped end mill with a tapered tip into the bore (storage chamber) 8 and then moving the end mill in the axial direction of the screw rotors 2, 3. The length of the long hole 5 in the short direction can be adjusted by the amount of protrusion of the end mill. Also, the length of the long hole 5 in the long direction can be adjusted by the amount of movement of the end mill in the axial direction of the screw rotors 2, 3. In other words, the opening area of ​​the long hole 5 is determined by the amount of protrusion and movement of the end mill.

[0024] When machining is performed using an end mill or the like with a V-shaped tapered tip, a V-groove having a pair of inclined surface portions 10a is formed on the upstream side of the slot 5. By arranging the tip portion 61 of the cartridge 6 along this V-groove, a pair of injection flow paths 13 are formed between the V-groove of the casing 1 and the tip portion 61 of the cartridge 6.

[0025] As shown in FIG. 3, the cartridge 6 and the communicating passage 10 are formed symmetrically in the left-right direction in the figure. By arranging the cartridge 6 at the center of the communicating passage 10 in the left-right direction in the figure, the cartridge 6 divides the space within the communicating passage 10 equally in the left-right direction in the figure. In other words, the pair of liquid supply paths 7 are formed symmetrically with the cartridge 6 in between. The cartridge 6 is arranged so that its top (tip) 6t is flush with the inner circumferential surface of the bore (storage chamber) 8. Note that, to reliably prevent the tip 61 of the cartridge 6 from contacting the screw rotors 2, 3, the top 6t of the tip 61 of the cartridge 6 may be positioned below the lower end surface of the bore 8.

[0026] The pair of liquid supply paths 7 have a pair of liquid supply storage spaces 12 that store the liquid supplied from the introduction path 9, and a pair of injection flow paths 13 that inject the liquid in the pair of liquid supply storage spaces 12 into the operating space C.

[0027] When the cartridge 6 is placed in the communicating passage 10, a pair of supply liquid storage spaces 12 are formed by a pair of wide surface portions 62 of the cartridge 6 and a pair of first flow path walls 10b and a pair of second flow path walls (not shown) that form the inner surface of the communicating passage 10.

[0028] When the cartridge 6 is placed in the communicating passage 10, the pair of ejection flow paths 13 are formed by the pair of tapered surface portions 63 of the cartridge 6 and the pair of inclined surface portions 10a that constitute the inner surface of the communicating passage 10. More specifically, when the tapered surface of the axial end portion 63a of the cartridge 6 abuts against the inclined surface portions 10a, the grooves 65 of the tapered surface portions 63 and the inclined surface portions 10a form the ejection flow paths 13 with a rectangular flow path cross section.

[0029] The flow path cross-sectional area of ​​the liquid supply storage space 12 is larger than the flow path cross-sectional area of ​​the jet flow path 13 to which liquid is supplied from the liquid supply storage space 12. Liquid is introduced into the liquid supply storage space 12 from the introduction path 9 provided in the horizontal direction, and the liquid introduced into the liquid supply storage space 12 flows toward the jet flow path 13 (i.e., upward in the figure). Because the flow path cross-sectional area of ​​the liquid supply storage space 12 is larger than the flow path cross-sectional area of ​​the jet flow path 13, the speed of the liquid flowing through the liquid supply storage space 12 is lower than the speed of the liquid flowing through the jet flow path 13. In this way, by configuring the liquid to flow within a wide space until it reaches the jet flow path 13, pressure loss can be minimized. This makes it possible to maintain a high pressure of the liquid in the jet flow path 13, allowing the liquid to be jetted from the jet flow path 13 with great force.

[0030] In each of the pair of injection passages 13, an injection opening 11 facing the working space C is formed by the top 6t of the tip portion 61 of the cartridge 6 and the elongated hole 5 of the casing 1. The injection opening 11 is a rectangular outlet for injecting liquid from the injection passage 13 into the working space C, i.e., the open end face of the injection passage 13, and is exposed inside the bore (storage chamber) 8.

[0031] The length of the injection openings 11 in the axial direction of the screw rotors 2, 3 (opening length) is longer than the length in the direction perpendicular to the axial direction (opening width). The injection openings 11 have their opening width and opening length determined so that the liquid is injected from the injection openings 11 in the form of a liquid film. In other words, the injection flow path 13 according to the first embodiment is a liquid film injection flow path that injects a liquid film. The liquid films injected from the injection openings 11 of a pair of injection flow paths 13 collide with each other in the working space C.

[0032] The pair of tapered surfaces 65a are formed so that the angle they form with each other is 30 degrees or more. Furthermore, the pair of inclined surface portions 10a are formed so that the angle they form with each other is 30 degrees or more. The tapered surfaces 65a and the inclined surface portions 10a are arranged parallel to each other. The liquid is injected into the working space C along the tapered surfaces 65a and the inclined surface portions 10a. In other words, the injection flow paths 13 are formed so that the angle (collision angle) θ between the injection directions of the liquid injected from each of the pair of injection flow paths 13 is 30 degrees or more.

[0033] 2, the base end 69 of the cartridge 6 is located below the introduction path 9 which extends horizontally. Although not shown, the communication path 10 extends to the lower end surface of the casing 1, and an insertion opening for inserting the cartridge 6 into the communication path 10 is formed in the lower end surface of the casing 1. A closing member (not shown) is attached to the insertion opening, and the insertion opening is closed by the closing member.

[0034] 5 is a diagram showing the results of a numerical analysis of the liquid (liquid film) sprayed from the spray flow path 13 formed by the cartridge 6. The black rectangular plane in the figure is a virtual plane that shows the pressure state of the liquid film, and is not actually provided in the product.

[0035] The pair of injection flow paths 13 formed by the inclined surface portion 10a of the casing 1 and the groove 65 of the cartridge 6 have a thin gap shape. Therefore, oil is injected from the pair of injection flow paths 13 in the form of a liquid film. The thin liquid film injected from one of the pair of injection flow paths 13 and the thin liquid film injected from the other of the pair of injection flow paths 13 collide within the working space C. Numerical analysis results confirmed that the collision of the injected liquids in the form of liquid films promotes thinning of the liquid and increases the surface area of ​​the liquid. The colliding liquid films spread and atomize into a plane, thereby promoting cooling of the compressed air within the working space C.

[0036] Thus, in this embodiment, the upstream side of the elongated hole 5 in the casing 1 is a space (communicating passage 10) capable of accommodating the cartridges 6 for forming the flow passages, and a pair of liquid supply paths 7 are formed by placing the flat cartridges 6 in the communicating passage 10 in the casing 1. The liquid is ejected into the working space C via the liquid supply paths 7 formed by the outer surfaces of the cartridges 6 and the casing 1. Note that in this embodiment, an ejection opening 11 is formed extending along the axial direction of the screw rotors 2, 3, and a thin liquid film is ejected from the ejection opening 11.

[0037] Here, a compressor 900 according to a comparative example of this embodiment will be described with reference to Figs. 6 and 7. As shown in Figs. 6 and 7, in the compressor 900 according to the comparative example of this embodiment, an injection flow path 913 is formed by drilling holes in the casing 1. The injection flow path 913 is a small-diameter circular opening that penetrates from the introduction path into the bore 8. Liquid is injected in a cylindrical shape from this injection flow path 913. However, in such an injection flow path (drilled hole) 913, the liquid does not diffuse, making it difficult to promote cooling.

[0038] 1 to 5, the axial lengths of the screw rotors 2 and 3 in the cartridge 6 and the elongated hole 5 are increased, so that the oil is sprayed in the form of a thin liquid film while ensuring the supply of liquid, and the liquid films collide with each other, thereby effectively diffusing the liquid. This effectively promotes cooling of the compressed air in the working space C.

[0039] In addition, in this embodiment, grooves 65 are formed on the outer surface of the cartridge 6, and the cartridge 6 is placed in a communication passage 10 formed in the casing 1, whereby an ejection flow passage 13 is formed by the casing 1 and the outer surface of the cartridge 6, which is a separate member from the casing 1. Therefore, this has superior workability compared to a configuration in which multiple flow passages are formed inside the cartridge 6 to increase the flow rate of liquid, such as the technology described in Patent Document 1 (hereinafter also referred to as prior art).

[0040] The cartridge 6 is detachable from the casing 1. Therefore, maintenance such as cleaning of the injection flow path 13 can be easily performed by removing the cartridge 6 from the casing 1. Furthermore, when the operating conditions of the compressor 100 change, the cartridge 6 attached to the casing 1 can be changed to form a liquid supply path 7 that suits the changed operating conditions.

[0041] According to the above-described embodiment, the following advantageous effects are achieved.

[0042] (1) The compressor 100 is a liquid-cooled screw compressor that sucks in air (gas) and generates compressed air (compressed gas). The compressor 100 includes screw rotors 2 and 3, a casing 1 that houses the screw rotors 2 and 3 and forms a working space C together with the screw rotors 2 and 3, and a cartridge 6 that is a separate member from the casing 1. The casing 1 and the outer surface of the cartridge 6 form a liquid supply path 7 that supplies liquid to the working space C.

[0043] In this configuration, the amount of liquid (refrigerant) supplied into the working space C can be adjusted by processing the outer shape of the cartridge 6, thereby preventing a shortage of liquid. Therefore, according to this embodiment, it is possible to provide a compressor 100 that is excellent in processability and maintainability of the liquid supply path 7 and that can easily improve the cooling performance for the air (gas) in the working space C. As described above, since the shape of the liquid supply path 7 can be determined by processing the outer shape of the cartridge 6, processing costs can be reduced compared to when the liquid supply path 7 is formed inside the cartridge 6. As a result, the manufacturing costs of the compressor 100 can be reduced.

[0044] (2) The casing 1 has a bore (storage chamber) 8 that stores the screw rotors 2, 3, an introduction passage 9 through which liquid is introduced from outside the casing 1, and a communication passage 10 that communicates the bore 8 with the introduction passage 9. When the cartridge 6 is placed in the communication passage 10, a pair of ejection passages 13 are formed by the tip end 61 of the cartridge 6 and the inner surface of the communication passage 10. The liquids ejected from the pair of ejection passages 13 collide with each other within the working space C.

[0045] According to this configuration, by causing the liquids injected from the pair of injection channels 13 to collide with each other, it is possible to diffuse the atomized liquid over a wide range within the working space C. This makes it possible to improve the cooling performance for the air within the working space C compared to when the injected liquids are not caused to collide with each other (see FIGS. 6 and 7).

[0046] (3) The ejection flow path 13 according to this embodiment is formed by only one pair of tapered surface portions 63 and one pair of inclined surface portions 10a by disposing the cartridge 6 in the communication path 10. The tapered surface portion 63 has a groove 65 formed therein that can eject the liquid (refrigerant) in the form of a liquid film. In other words, the ejection flow path 13 according to this embodiment is a liquid film ejection flow path that ejects a liquid film. The liquid films ejected from the pair of ejection flow paths (liquid film ejection flow paths) 13 collide with each other in the working space C.

[0047] With this configuration, the collision of the liquid films with each other promotes thinning of the liquid and allows the atomized liquid to be dispersed over a wide area. Thinning and atomization of the liquid increases the surface area of ​​the liquid (i.e., the heat exchange area), allowing the compressed air in the working space C to be cooled effectively and improving compressor performance.

[0048] (4) The pair of liquid supply paths 7 have a pair of liquid supply storage spaces 12 that store the liquid supplied from the introduction path 9, and a pair of ejection flow paths 13 that eject the liquid in the liquid supply storage spaces 12 into the working space C. The pair of liquid supply storage spaces 12 are formed by a pair of wide surface portions 62 of the cartridge 6 and the inner surface of the communicating path 10, and the pair of ejection flow paths 13 are formed by a pair of tapered surface portions 63 of the cartridge 6 and a pair of inclined surface portions 10a of the communicating path 10. The flow path cross-sectional area of ​​the pair of liquid supply storage spaces 12 formed upstream of the pair of ejection flow paths 13 is larger than the flow path cross-sectional area of ​​the pair of ejection flow paths 13.

[0049] In this configuration, a liquid supply storage space 12 having a flow path cross-sectional area larger than that of the ejection flow path 13 is formed from the introduction path 9 to the ejection flow path 13, thereby reducing the pressure loss of the liquid flowing through the liquid supply path 7. This allows the liquid under high pressure to be ejected forcefully from the ejection opening 11, allowing the liquid to be dispersed over a wider area.

[0050] (5) The pair of liquid supply paths 7 are formed symmetrically with respect to the cartridge 6. This makes it possible to reduce the difference in pressure of the liquid in the upstream liquid supply path 7 of the pair of liquid supply paths 7 and the downstream liquid supply path 7 of the pair of liquid supply paths 7. This makes it possible to make the speed of the liquid ejected from each of the pair of ejection flow paths 13 approximately the same, making it easy to control the location where the liquids collide. In this embodiment, liquid films are ejected evenly from each of the pair of ejection flow paths 13, so the liquid films after collision extend straight upward.

[0051] (6) The cross-sectional shape of the introduction path 9 is circular, and the cartridge 6 has a circular through-hole 66 disposed in the introduction path 9. The opening area of ​​the through-hole 66 is equal to or larger than the cross-sectional area of ​​the introduction path 9. If the opening area of ​​the through-hole 66 were smaller than the cross-sectional area of ​​the introduction path 9, the pressure loss of the liquid passing through the through-hole 66 would increase. As a result, the difference in pressure between the liquid in the upstream liquid supply path 7 and the liquid in the downstream liquid supply path 7 would increase. In this case, a difference in speed occurs between the liquid ejected from one of the pair of ejection paths 13 and the liquid ejected from the other of the pair of ejection paths 13, making it difficult to control the collision site between the liquids. In contrast, in this embodiment, the opening area of ​​the through-hole 66 disposed in the introduction path 9 is equal to or larger than the cross-sectional area of ​​the introduction path 9, thereby suppressing the pressure loss of the liquid passing through the through-hole 66. This makes it possible to reduce the pressure difference and speed difference between the liquids ejected from the pair of ejection openings 11, making it easier to control the locations where the liquids collide with each other.

[0052] (7) The ejection flow paths 13 are formed so that the angle (collision angle) θ between the ejection directions of the liquids ejected from each of the paired ejection flow paths 13 is 30 degrees or more. In this embodiment, the angle between the extension lines of a pair of ejection flow paths 13 is 30 degrees or more. With this configuration, the liquid can be atomized more effectively and the surface area of ​​the liquid can be increased compared to when the liquids are collided with each other at a collision angle θ of less than 30 degrees.

[0053] (8) The communication passage 10 and the bore 8 are connected by the elongated hole 5 along the axial direction of the screw rotors 2, 3, and each of the pair of injection flow passages 13 has an injection opening 11 facing the working space C formed by the tip end 61 of the cartridge 6 and the elongated hole 5. With this configuration, the shape and opening area of ​​the injection opening 11 can be adjusted by adjusting the shape of the elongated hole 5 and the shape of the tip end 61 of the cartridge 6.

[0054] Second Embodiment A cartridge 6B according to a second embodiment of the present invention will be described with reference to Figures 8 and 9. Note that components that are the same as or equivalent to those described in the first embodiment are given the same reference symbols, and differences will be mainly described. Figure 8 is a perspective view of the cartridge 6B according to the second embodiment. Figure 9 is a view similar to Figure 5, showing the results of a numerical analysis of liquid ejected from an ejection flow path 13B formed by the cartridge 6B according to the second embodiment.

[0055] The casing 1 according to the second embodiment is similar to that according to the first embodiment, but the cartridge 6B according to the second embodiment is different from the cartridge 6 described in the first embodiment. In the first embodiment, one groove 65 was formed in each of the pair of tapered surface portions 63 (see FIGS. 3 and 4). In contrast, in the second embodiment, as shown in FIG. 8, a plurality of grooves 67B are formed in each of the pair of tapered surface portions 63B, extending linearly from the wide surface portion 62 to the apex (tip) 6Bt of the tip portion 61. The plurality of grooves 67B are arranged along the axial direction of the screw rotors 2 and 3. The plurality of grooves 67B are formed along a direction perpendicular to the axial direction of the screw rotors 2 and 3.

[0056] In the first embodiment, an example has been described in which the cartridge 6 is disposed in the communicating passage 10, and thereby only one pair of ejection flow paths 13 is formed for one cartridge 6 by the pair of tapered surface portions 63 and the pair of inclined surface portions 10a (see FIGS. 3 and 4). In contrast to this, in the second embodiment, the cartridge 6B is disposed in the communicating passage 10, and thereby multiple pairs (six pairs in the illustrated example) of ejection flow paths 13B are formed for one cartridge 6B by the plurality of grooves 67B of the pair of tapered surface portions 63B and the pair of inclined surface portions 10a.

[0057] Furthermore, the jet flow paths 13 according to the first embodiment are liquid film jet flow paths that jet a liquid film. In contrast, the jet flow paths 13B according to the second embodiment are jet jet jet flow paths that jet a jet. In each of the pairs of jet flow paths 13B, an jet opening 11B facing the working space C is formed by the top 6Bt of the tip end 61 of the cartridge 6B and the elongated hole 5.

[0058] The jets ejected from the pairs of jet ejection passages 13B collide with each other in the working space C.

[0059] Furthermore, similarly to the first embodiment, the sum of the flow path cross-sectional areas of a pair of supply liquid storage spaces 12 is greater than the sum of the flow path cross-sectional areas of the plurality of pairs of ejection flow paths 13.

[0060] In the second embodiment, a plurality of pairs of jet flow paths (jet jet flow paths) 13B are formed by the casing 1 and the outer surface of the cartridge 6B. The jets jetted from each pair of jet flow paths 13B collide with each other in the working space C. According to the second embodiment, as shown in FIG. 9, the collision of the jets causes the liquid to spread in a fan shape in the axial direction of the screw rotors 2 and 3, thereby increasing the surface area of ​​the liquid. Therefore, according to the second embodiment, as in the first embodiment, it is possible to provide a compressor 100 that is excellent in workability and maintainability of the liquid supply path 7 and that can easily improve the cooling performance for the air (gas) in the working space C.

[0061] Third Embodiment A cartridge 6C according to a third embodiment of the present invention will be described with reference to Figs. 10 to 12. Components that are the same as or equivalent to those described in the second embodiment are given the same reference symbols, and differences will be mainly described. Fig. 10 is a perspective view of the cartridge 6C according to the third embodiment. Fig. 11 is a plan view of the cartridge 6C of Fig. 10 as viewed from the XI direction. Fig. 12 is a view similar to Figs. 5 and 9, and shows the results of a numerical analysis of liquid ejected from an ejection flow path 13C formed by the cartridge 6C according to the third embodiment.

[0062] In the second embodiment, the plurality of grooves 67B of the tapered surface portion 63B are formed along a direction perpendicular to the axial direction of the screw rotors 2 and 3 (see FIG. 8). In contrast, in the third embodiment, as shown in FIGS. 10 and 11, the plurality of grooves 67C of the tapered surface portion 63C are formed along directions inclined with respect to both the axial direction of the screw rotors 2 and 3 and the direction perpendicular to the axial direction.

[0063] As shown in FIG. 11, in the third embodiment, the extending direction D1 of the groove 67C in a plan view intersects with both the axial direction D0 of the screw rotors 2 and 3 and a direction perpendicular to the axial direction D0 (a plane perpendicular to the axial direction D0).

[0064] In the third embodiment, similar to the second embodiment, the casing 1 and the outer surface of the cartridge 6C form multiple pairs of ejection channels (jet ejection channels) 13C, thereby achieving the same effects as the second embodiment. Furthermore, in the third embodiment, the ejection channels 13C are formed obliquely with respect to the axial direction D0 and the direction perpendicular to the axial direction D0 in a plan view. Therefore, as shown in FIGS. 11 and 12 , when the jets collide with each other, the liquid spreads in a fan shape in a direction perpendicular to the extension direction D1 of the grooves 67C, thereby increasing the surface area of ​​the liquid. According to the third embodiment, by adjusting the angle φ of the multiple grooves 67 (the angle between the axial direction D0 and the extension direction D1 of the grooves 67C in a plan view), the liquid ejected from the paired ejection channels 13C and colliding with each other can be dispersed in a direction along the tooth grooves of the screw rotors 2 and 3 or toward the tooth groove cross section.

[0065] <Fourth embodiment> A cartridge 6D according to a fourth embodiment of the present invention will be described with reference to Fig. 13. Components that are the same as or equivalent to those described in the third embodiment will be given the same reference symbols, and differences will be mainly described. Fig. 13 is a perspective view of the cartridge 6D according to the fourth embodiment.

[0066] The fourth embodiment differs from the third embodiment in that a groove 68 extending in the axial direction of the screw rotors 2, 3 is formed in the top (tip) of the tip portion 61 of the cartridge 6D. The groove 68 is formed to expand the liquid supply range into the working space C. In this embodiment, the groove 68 is formed with a V-shaped cross section that is recessed from the tip side of the tip portion 61 toward the base end side.

[0067] In the third embodiment, as shown in FIG. 10, the ejection opening 11C is configured to open on the top surface, and a pair of ejection channels 13C is separated by a partition. In contrast, in the fourth embodiment, as shown in FIG. 13, the ejection opening 11D is formed as a V-shaped groove 68, and a space is formed between the pair of ejection openings 11D. In the third embodiment, depending on the diffusion conditions after the collision of the jets, the partition in the groove 67C immediately before ejection may hinder diffusion. In contrast, in the cartridge 6D according to the fourth embodiment, the V-shaped groove 68 is formed at the tip of the tip portion 61, so that the partition in the groove 67D immediately before ejection is eliminated, and the impediment to diffusion after the collision of the jets is suppressed. In other words, according to the fourth embodiment, the liquid can be diffused over a wider area than in the third embodiment.

[0068] As described above, in the compressors according to the first to fourth embodiments, by combining the casing and the outer surface of the cartridge, one or more pairs of injection flow paths are formed that allow the injected liquids to collide with each other. Therefore, by simply changing the processing details and the length of one cartridge provided for one screw rotor (the axial direction of the screw rotors 2, 3), it is possible to improve the cooling performance in the working space C and easily change the flow rate of the liquid used to cool the compressed air.

[0069] <Other embodiments> The present invention is not limited to the above-described embodiments, but includes various modifications. The above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those including all of the described configurations. That is, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is also possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0070] Although the above-described embodiment has been described taking a twin-rotor liquid-cooled screw compressor as an example, the present invention can also be applied to screw compressors other than the twin-rotor type, such as single-rotor or triple-rotor types. Furthermore, the gas compressed by the compressor is not limited to air. [Explanation of symbols]

[0071] 1... casing, 2... drive rotor (screw rotor), 3... driven rotor (screw rotor), 5... elongated hole, 6, 6B, 6C, 6D... cartridge, 6t, 6Bt, 6Dt... top (tip), 7... liquid supply path, 8... bore (storage chamber), 9... introduction path, 10... communication path, 10a... inclined surface portion, 10b... first flow path wall, 10c... step portion, 11, 11C, 11D... injection opening, 12... liquid supply storage space, 13... injection flow path (liquid film injection flow path) ), 13B... injection flow path (jet injection flow path), 13C... injection flow path (jet injection flow path), 61... tip portion, 62... wide surface portion, 63, 63B, 63C... tapered surface portion, 63a... axial end portion, 64... narrow surface portion, 65... groove (recess), 65a... bottom surface (tapered surface), 66... ​​through hole, 67, 67B, 67C, 67D... groove, 68... groove, 69... base end portion, 100... compressor (liquid-cooled screw compressor), C... working space (working chamber), θ... collision angle

Claims

1. A liquid-cooled screw compressor that sucks in gas and generates compressed gas, A screw rotor; a casing that houses the screw rotor and defines an operating space together with the screw rotor; a cartridge that is a separate member from the casing, a liquid supply path for supplying liquid to the working space is formed by the casing and an outer surface of the cartridge; the casing has a storage chamber that stores the screw rotor, an introduction passage through which a liquid is introduced from the outside of the casing, and a communication passage that communicates the storage chamber with the introduction passage, When the cartridge is disposed in the communication passage, at least one pair of ejection flow passages is formed by the tip end of the cartridge and the inner surface of the communication passage, The liquids ejected from the at least one pair of ejection channels collide with each other in the working space. Liquid-cooled screw compressor.

2. 2. The liquid-cooled screw compressor according to claim 1, The cartridge has a pair of wide surfaces facing each other, The tip of the cartridge is formed in a tapered shape having a pair of tapered surfaces, the communication passage of the casing has a pair of inclined surface portions facing the pair of tapered surface portions of the cartridge, a pair of the liquid supply paths are formed by the casing and an outer surface of the cartridge; The pair of liquid supply paths include: a pair of liquid supply storage spaces formed by the pair of wide surface portions of the cartridge and an inner surface of the communication passage, the liquid supply storage spaces storing the liquid supplied from the introduction passage; one or more pairs of ejection flow paths formed by the pair of tapered surface portions of the cartridge and the pair of inclined surface portions of the communication path, for ejecting liquid from the supply liquid storage space into the working space, The flow path cross-sectional area of ​​the pair of supply liquid storage spaces is larger than the flow path cross-sectional area of ​​the pair or more of injection flow paths. Liquid-cooled screw compressor.

3. 3. The liquid-cooled screw compressor according to claim 2, When the cartridge is disposed in the communication passage, only one pair of ejection flow passages are formed by the pair of tapered surface portions and the pair of inclined surface portions, the ejection flow path is a liquid film ejection flow path that ejects a liquid film, The liquid films injected from the pair of liquid film injection flow paths collide with each other in the working space. Liquid-cooled screw compressor.

4. 3. The liquid-cooled screw compressor according to claim 2, When the cartridge is disposed in the communication passage, a plurality of pairs of the ejection flow passages are formed by the pair of tapered surface portions and the pair of inclined surface portions, the jet flow path is a jet jet flow path that jets a jet, The jets ejected from the pairs of jet ejection passages collide with each other in the working space. Liquid-cooled screw compressor.

5. 5. The liquid-cooled screw compressor according to claim 4, a plurality of grooves extending linearly from the wide surface portion to the tip of the tip portion are formed on each of the pair of tapered surface portions; The plurality of pairs of jet injection flow paths are formed by the plurality of grooves and the inclined surface portions. Liquid-cooled screw compressor.

6. 2. The liquid-cooled screw compressor according to claim 1, the communication passage and the storage chamber are connected by a long hole extending along the axial direction of the screw rotor, In each of the at least one pair of injection flow paths, an injection opening portion facing the working space is formed by the tip end portion of the cartridge and the elongated hole. Liquid-cooled screw compressor.

7. 2. The liquid-cooled screw compressor according to claim 1, The ejection flow paths are formed so that the angle between the ejection directions of the liquid ejected from each of the paired ejection flow paths is 30 degrees or more. Liquid-cooled screw compressor.

8. 6. The liquid-cooled screw compressor according to claim 5, The plurality of grooves are formed along a direction perpendicular to the axial direction of the screw rotor. Liquid-cooled screw compressor.

9. 6. The liquid-cooled screw compressor according to claim 5, The plurality of grooves are formed along directions inclined with respect to the axial direction of the screw rotor and with respect to a direction perpendicular to the axial direction. Liquid-cooled screw compressor.

10. 6. The liquid-cooled screw compressor according to claim 5, A groove extending in the axial direction of the screw rotor is formed at the tip of the tip portion of the cartridge. Liquid-cooled screw compressor.

11. 3. The liquid-cooled screw compressor according to claim 2, The pair of liquid supply paths are formed symmetrically with the cartridge in between. Liquid-cooled screw compressor.

12. 3. The liquid-cooled screw compressor according to claim 2, The cross-sectional shape of the introduction path is circular, the cartridge has a circular through-hole disposed in the introduction path; The opening area of ​​the through hole is equal to or larger than the cross-sectional area of ​​the flow path of the introduction path. Liquid-cooled screw compressor.

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