Liquid-cooled screw compressor

Abstract

A liquid-cooled screw compressor (100) that sucks in gas and generates compressed gas is provided with screw rotors (2, 3), a housing (1) that houses the screw rotors (2, 3) and forms a working space (C) together with the screw rotors (2, 3), and a plug (6) that is a different member from the housing (1). A liquid supply passage (7) for supplying a liquid to the working space (C) is formed by the outer surfaces of the housing (1) and the plug (6).

Description

Technical Field

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

[0002] A liquid-cooled screw compressor is known, which has a screw rotor and a housing that accommodates the screw rotor and forms a working space together with the screw rotor, and supplies liquid into the working space to cool the gas in the working space. In addition to cooling, the liquid supplied into the working space is also used to seal the internal gap generated between the screw rotor and the housing and to lubricate the sliding part.

[0003] Patent Document 1 proposes a technique for atomizing liquid by causing liquid supplied to a working space to collide with each other in order to improve the performance of a compressor.

[0004] In the compressor described in Patent Document 1, an oil supply nozzle insertion hole is provided in the housing, and an oil supply nozzle having a plurality of oil supply paths for collision jets inside is inserted into the oil supply nozzle insertion hole. The oil supply path is composed of a main oil supply path and a small-diameter auxiliary oil supply path branched from the main oil supply path and arranged in a U-shaped shape. In the compressor described in Patent Document 1, since the oil supply nozzle can be disassembled, the maintainability is good compared with the case where the oil supply path for collision jets is directly processed on the housing.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2018-35782 Summary of the invention

[0008] Technical problem to be solved by the invention

[0009] Patent Document 1 discloses an oil supply nozzle having a plurality of oil supply paths in order to supply more liquid into the working space and improve the cooling efficiency (see Patent Document 1). Fig. 9 However, in this oil supply nozzle, it is necessary to form a plurality of oil supply paths composed of a main oil supply path and auxiliary oil supply paths arranged in a U shape inside the oil supply nozzle, so there is a concern that it will take time and effort to process and the processing cost will increase.

[0010] An object of the present invention is to provide a liquid-cooled screw compressor which is excellent in processability and maintainability and can improve the cooling performance of gas in a working space.

[0011] Technical solutions to solve problems

[0012] A liquid-cooled screw compressor according to one embodiment of the present invention is a liquid-cooled screw compressor that generates compressed gas by sucking in gas, and comprises a screw rotor, a shell that accommodates the screw rotor and forms a working space together with the screw rotor, and a plug-in component that is a component different from the shell, wherein the outer surfaces of the shell and the plug-in component form a liquid supply passage for supplying liquid to the working space.

[0013] Effects of the Invention

[0014] According to the present invention, it is possible to provide a liquid-cooled screw compressor which is excellent in processability and maintainability and can improve the cooling performance of gas in a working space. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a top cross-sectional view of the liquid-cooling type screw compressor according to the first embodiment.

[0016] Figure 2 yes Figure 1 II-II cross-sectional view.

[0017] Figure 3 yes Figure 2 An enlarged cross-sectional view of part III.

[0018] Figure 4 It is a perspective view of the plug fitting according to the first embodiment.

[0019] Figure 5 It is a diagram showing the results of numerical analysis of the liquid ejected from the ejection flow path formed by the plug according to the first embodiment.

[0020] Figure 6 It is a top cross-sectional view of a liquid-cooling type screw compressor according to a comparative example of the present embodiment.

[0021] Figure 7 yes Figure 6 VII-VII cross-section diagram.

[0022] Figure 8 It is a perspective view of the plug fitting according to the second embodiment.

[0023] Fig. 9 It is a diagram showing the results of numerical analysis of the liquid ejected from the ejection flow path formed by the plug according to the second embodiment.

[0024] Fig.10 It is a perspective view of the plug fitting according to the third embodiment.

[0025] Fig.11 Observed from the XI direction Fig.10 A top view of the plug-in component.

[0026] Fig.12It is a diagram showing the results of numerical analysis of the liquid ejected from the ejection flow path formed by the plug according to the third embodiment.

[0027] Fig.13 It is a perspective view of a plug fitting according to a fourth embodiment. DETAILED DESCRIPTION

[0028] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0029] <First Embodiment>

[0030] Reference Figure 1 to Figure 5 , a liquid-cooled screw compressor (hereinafter, also referred to as a compressor) 100 according to a first embodiment of the present invention will be described. Figure 1 is a top cross-sectional view of the compressor 100 . Figure 2 yes Figure 1 II-II cross-sectional view. Figure 1 and Figure 2 As shown, the compressor 100 includes a driving rotor 2 and a driven rotor 3 as a pair of helical rotors that rotate in mesh with each other, and a housing 1 that rotatably accommodates the driving rotor 2 and the driven rotor 3. The compressor 100 generates compressed air (compressed gas) by rotating the helical rotors 2 and 3 to suck in air (gas).

[0031] A plurality of helical male teeth are formed on the driving rotor (male rotor) 2. A plurality of helical female teeth are formed on the driven rotor (female rotor) 3. A cavity 8 as a storage chamber for storing the driving rotor 2 and the driven rotor 3 in a meshing state, an air intake port, and an exhaust port for exhausting compressed air are formed in the housing 1. A plurality of working spaces (working chambers) C for compressed air are formed by the inner wall surface of the pair of helical rotors 2 and 3 and the cavity 8.

[0032] A prime mover such as an electric motor is connected to the driving rotor 2. When the driving rotor 2 starts to rotate by the prime mover, the driven rotor 3 meshing with the driving rotor 2 also starts to rotate. As a result, air is sucked into the working space C from the suction port. The working space C moves from the suction port side to the discharge port side as the screw rotors 2 and 3 rotate, and its volume decreases as it moves. As the volume of the working space C decreases, the air moves toward the discharge port side while being compressed, and is discharged from the discharge port to the outside of the compressor 100.

[0033] In the liquid-cooled screw compressor 100, in order to suppress the temperature rise of the air caused by the heat generated by the compressed air, a cooling liquid (such as 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 the gap between the screw rotors 2, 3 and the inner wall surface of the bore 8 and the gap between the meshing part of the driving rotor 2 and the driven rotor 3, and to lubricate the sliding parts of the screw rotors 2, 3.

[0034] like Figure 2 As shown, the compressor 100 is formed with a liquid supply passage 7 for supplying liquid to the working space C. The liquid supply passage 7 is provided on the driving rotor 2 side and the driven rotor 3 side, respectively, but the structure is the same in both sides, so one side will be described as a representative below.

[0035] The housing 1 has: an introduction passage 9 for introducing liquid from the outside of the housing 1; a communication passage 10 for connecting the storage chamber 8 with the introduction passage 9; and a long hole 5 for connecting the communication passage 10 with the storage chamber 8. Figure 1 and Figure 2 As shown, the long hole 5 is an opening extending along the rotation axis direction (hereinafter also referred to as the axial direction) of the screw rotors 2 and 3. In other words, the long hole 5 is an opening surface located at the boundary of the communication path 10 and the storage chamber 8, and is formed into a rectangular shape with the axial direction of the screw rotors 2 and 3 as the length direction and the direction orthogonal to the axial direction (horizontal direction) as the short side direction. The long hole 5 of this embodiment has a pair of long sides facing each other and a pair of semicircular arcs connecting the pair of long sides to each other at both ends. The long hole 5 is formed in the male side cavity 8 to accommodate the driving rotor 2 and the female side cavity 8 to accommodate the driven rotor 3.

[0036] The communication passage 10 forms a flat rectangular space, and a flat rectangular plug (cartridge, refillable box) 6 is arranged in the communication passage 10, so that a pair of liquid supply passages 7 are formed by the inner wall surface of the housing 1 and the outer surface of the plug 6. The plug 6 is detachable relative to the housing 1.

[0037] Reference Figure 3 and Figure 4 , the structure of the liquid supply passage 7 is described in detail. Figure 3 yes Figure 2 An enlarged cross-sectional view of part III, Figure 4 6 is a three-dimensional diagram of the plug-in component. Figure 3 and Figure 4 As shown, the plug 6 is a rectangular flat plate having a pair of wide face portions 62 facing each other and a pair of narrow face portions 64 facing each other. The wide face portions 62 and the narrow face portions 64 are planes and are orthogonal to each other. The pair of wide face portions 62 are parallel to each other, and the pair of narrow face portions 64 are parallel to each other. When the plug 6 is arranged in the communication passage 10, the base end portion 69 (see Figure 4 ) is located on the introduction passage 9 side, and the front end portion 61 is located on the cavity 8 side. That is, the plug 6 extends in the vertical direction from the introduction passage 9 side to the cavity 8 side in the communication passage 10. The area of ​​the wide surface 62 is larger than the area of ​​each of the base end face (lower end face) and the narrow surface 64 of the plug 6. The base end face of the plug 6 is a plane orthogonal to the wide surface 62 and the narrow surface 64.

[0038] The plug 6 has a through hole 66 extending from one wide surface 62 to the other wide surface 62. The through hole 66 and the introduction passage 9 extending in the horizontal direction (see Figure 2 ) is circular in cross-sectional shape. The opening area of ​​the through hole 66 is preferably greater than the flow path cross-sectional area of ​​the introduction passage 9. That is, the diameter of the through hole 66 is preferably the same as or larger than the diameter of the introduction passage 9. The plug 6 is arranged in the communication passage 10 in such a manner that the central axis of the through hole 66 is consistent with the central axis of the introduction passage 9. Thus, when the plug 6 is observed from the thickness direction, the inner peripheral surface of the introduction passage 9 is arranged as a whole so as to be accommodated inside the through hole 66.

[0039] The front end portion 61 of the plug-in component 6 is formed into a tapered shape having a pair of tapered surface portions 63. That is, the front end portion 61 decreases in thickness (the distance between the pair of tapered surface portions 63) as it goes toward its top end (top portion 6t). A groove (recess) 65 is formed in the tapered surface portion 63 from the upper end of the wide surface portion 62 to the top portion 6t of the plug-in component 6. The top portion 6t is a plane parallel to the base end surface of the plug-in component 6. The groove 65 is formed between the axial ends 63a at both axial ends of the tapered surface portion 63. The bottom surface (hereinafter also referred to as tapered surface) 65a of the groove 65 is a plane, and is inclined relative to the wide surface portion 62 in such a manner that the distance between the pair of tapered surfaces 65a becomes shorter as it approaches the top portion 6t from the wide surface portion 62. The pair of tapered surfaces 65a are connected to each other through the top portion 6t of the plug-in component 6.

[0040] like Figure 3 As shown, the communication passage 10 is formed with: a pair of inclined surfaces 10a opposite to the pair of tapered surfaces 63 of the plug 6; a pair of first flow path walls 10b opposite to the pair of wide width surfaces 62; and a pair of second flow path walls (not shown) opposite to the pair of narrow width surfaces 64. In addition, in the present embodiment, a step portion 10c is formed between the tapered surface 63 and the first flow path wall 10b, but the step portion 10c may be omitted. That is, the tapered surface 63 and the first flow path wall 10b may also be directly connected.

[0041] The communication path 10 is formed, for example, by protruding an end mill having a V-shaped tip into the bore (accommodation chamber) 8 and then moving the end mill in the axial direction of the screw rotors 2 and 3. The length of the short side direction of the long hole 5 is adjusted by the protrusion amount of the end mill. In addition, the length of the long hole 5 in the longitudinal direction can be adjusted by the movement amount of the end mill in the axial direction of the screw rotors 2 and 3. That is, the opening area of ​​the long hole 5 is determined by the protrusion amount and movement amount of the end mill.

[0042] When machining is performed using an end mill with a V-shaped tip tapered, a V-groove having a pair of inclined surface portions 10a is formed on the upstream side of the long hole 5. By arranging the front end portion 61 of the plug 6 along the V-groove, a pair of injection flow paths 13 are formed between the V-groove of the housing 1 and the front end portion 61 of the plug 6.

[0043] like Figure 3 As shown, the plug-in component 6 and the connecting passage 10 are formed into a symmetrical shape in the left-right direction of the figure. By arranging the plug-in component 6 at the center of the connecting passage 10 in the left-right direction of the figure, the space in the connecting passage 10 is equally divided by the plug-in component 6 in the left-right direction of the figure. That is, a pair of liquid supply passages 7 are formed into a symmetrical shape across the plug-in component 6. The plug-in component 6 is arranged in such a way that its top (top end) 6t is in the same plane (flush) with the inner peripheral surface of the cavity (storage chamber) 8. In addition, in order to reliably prevent the front end portion 61 of the plug-in component 6 from contacting the spiral rotors 2 and 3, the top 6t of the front end portion 61 of the plug-in component 6 can also be located at a position lower than the lower end surface of the cavity 8.

[0044] The pair of liquid supply passages 7 includes a pair of liquid supply storage spaces 12 for storing the liquid supplied from the introduction passage 9 , and a pair of injection flow paths 13 for injecting the liquid in the pair of liquid supply storage spaces 12 into the working space C.

[0045] By arranging the plug 6 in the communication passage 10 , a pair of liquid supply storage spaces 12 are formed by a pair of wide surface portions 62 of the plug 6 , a pair of first flow passage walls 10 b constituting the inner surface of the communication passage 10 , and a pair of second flow passage walls (not shown).

[0046] By arranging the plug 6 in the communication passage 10, a pair of injection flow passages 13 are formed by a pair of tapered surface portions 63 of the plug 6 and a pair of inclined surface portions 10a constituting the inner surface of the communication passage 10. More specifically, the tapered surface of the axial end portion 63a of the plug 6 abuts against the inclined surface portion 10a, and the groove 65 of the tapered surface portion 63 and the inclined surface portion 10a form the injection flow passage 13 having a rectangular flow passage cross section.

[0047] The flow path cross-sectional area of ​​the liquid supply storage space 12 is larger than the flow path cross-sectional area of ​​the injection flow path 13 to which the liquid is supplied from the liquid supply storage space 12. The liquid is guided to the liquid supply storage space 12 from the inlet passage 9 arranged in the horizontal direction, and the liquid guided to the liquid supply storage space 12 flows toward the injection flow path 13 (i.e., above the figure). Since the flow path cross-sectional area of ​​the liquid supply storage space 12 is larger than the flow path cross-sectional area of ​​the injection flow path 13, the speed of the liquid flowing in the liquid supply storage space 12 is smaller than the speed of the liquid flowing in the injection flow path 13. In this way, by adopting a structure in which the liquid flows in a wider space until the liquid reaches the injection flow path 13, the pressure loss can be minimized. As a result, the pressure of the liquid in the injection flow path 13 can be maintained at a higher state, and the liquid can be strongly ejected from the injection flow path 13.

[0048] In each of the pair of injection flow paths 13, the top 6t of the front end portion 61 of the plug 6 and the long hole 5 of the housing 1 form an injection opening portion 11 facing the working space C. The injection opening portion 11 is a rectangular outlet for ejecting liquid from the injection flow path 13 into the working space C, that is, an opening end surface of the injection flow path 13, and is exposed in the cavity (storage chamber) 8.

[0049] The length of the screw rotors 2 and 3 in the axial direction (opening length) of the injection opening 11 is longer than the length (opening width) in the direction orthogonal to the axial direction. The injection opening 11 determines its opening width and opening length in such a way that the liquid is injected from the injection opening 11 in the form of a liquid film. That is, the injection flow path 13 of the first embodiment is a liquid film injection flow path for injecting a liquid film. The liquid films injected from the injection openings 11 of the pair of injection flow paths 13 collide with each other in the working space C.

[0050] A pair of tapered surfaces 65a are formed in such a way that the angle between them is 30 degrees or more. In addition, a pair of inclined surface parts 10a are formed in such a way that the angle between them is 30 degrees or more. The tapered surface 65a and the inclined surface part 10a are arranged in parallel. The liquid is ejected into the working space C along the tapered surface 65a and the inclined surface part 10a. That is, the jet flow path 13 is formed in such a way that the angle (collision angle) θ between the ejection directions of the liquids ejected from the paired ejection flow paths 13 is 30 degrees or more.

[0051] like Figure 2 As shown, the base end portion 69 of the plug 6 is located below the introduction passage 9 extending in the horizontal direction. Although not shown, the communication passage 10 extends to the lower end surface of the housing 1, and an insertion port for inserting the plug 6 into the communication passage 10 is formed on the lower end surface of the housing 1. In addition, a closing member (not shown) is installed at the insertion port, and the insertion port is blocked by the closing member.

[0052] Figure 5The figure shows the result of numerical analysis of the liquid (liquid film) ejected from the ejection flow path 13 formed by the plug 6. The black rectangular plane in the figure is a virtual plane showing the pressure state of the liquid film and is not actually provided in the product.

[0053] The flow path shape of a pair of injection flow paths 13 formed by the inclined surface 10a of the housing 1 and the groove 65 of the plug-in 6 is a thin gap shape. Therefore, oil is injected from the pair of injection flow paths 13 in a liquid film state. The thin liquid film injected from one of the pair of injection flow paths 13 collides with the thin liquid film injected from the other of the pair of injection flow paths 13 in the working space C. According to the numerical analysis results, it is confirmed that by the collision of liquids injected in the liquid film state, thin film formation can be promoted and the surface area of ​​the liquid can be expanded. The liquid films after the collision spread in a planar shape and atomize each other, thereby promoting the cooling of the compressed air in the working space C.

[0054] As described above, in the present embodiment, the upstream side of the long hole 5 of the housing 1 becomes a space (communication path 10) capable of accommodating the plug 6 for forming the flow path, and a pair of liquid supply paths 7 are formed by arranging the flat plug 6 in the communication path 10 of the housing 1. The liquid is ejected into the working space C through the outer surface of the plug 6 and the liquid supply path 7 formed by the housing 1. In addition, in the present embodiment, an ejection opening 11 extending along the axial direction of the screw rotors 2 and 3 is formed, and a thin liquid film is ejected from the ejection opening 11.

[0055] Here, refer to Figure 6 and Figure 7 , a compressor 900 of a comparative example of the present embodiment will be described. Figure 6 and Figure 7 As shown, in the compressor 900 of the comparative example of the present embodiment, the injection flow path 913 is formed by drilling the housing 1. The injection flow path 913 is a small-diameter circular opening that penetrates from the introduction passage into the bore 8. Liquid is ejected cylindrically from the injection flow path 913. However, in such an injection flow path (drilled hole) 913, since the liquid does not spread, it is difficult to promote cooling.

[0056] In contrast, Figure 1 to Figure 5 In the compressor 100 of the present embodiment shown, by lengthening the axial length of the screw rotors 2 and 3 in the plug 6 and the long hole 5, it is possible to ensure the supply amount of liquid and spray the oil in a thin liquid film form, and effectively diffuse the liquid by making the liquid films collide with each other. Thus, the cooling of the compressed air in the working space C is effectively promoted.

[0057] In addition, in this embodiment, the groove 65 is formed on the outer surface of the plug 6, and the plug 6 is arranged in the communication path 10 formed in the housing 1, thereby forming the injection flow path 13 by the housing 1 and the outer surface of the plug 6, which is a component separated from the housing 1 (a component different from the housing). Therefore, compared with the structure in which a plurality of flow paths are formed inside the plug 6 in order to increase the flow rate of the liquid as described in Patent Document 1 (hereinafter also referred to as the prior art), the processability is excellent.

[0058] In addition, the plug 6 is detachable from the housing 1. Therefore, maintenance such as cleaning of the injection flow path 13 can be easily performed by removing the plug 6 from the housing 1. In addition, when the operating conditions of the compressor 100 are changed, by changing the plug 6 mounted on the housing 1, the liquid supply passage 7 that conforms to the changed operating conditions can be formed.

[0059] According to the above-mentioned embodiment, the following effects are achieved.

[0060] (1) The compressor 100 is a liquid-cooled screw compressor that sucks in air (gas) to generate compressed air (compressed gas). The compressor 100 includes screw rotors 2 and 3; a housing 1 that accommodates the screw rotors 2 and 3 and forms a working space C together with the screw rotors 2 and 3; and a plug 6 that is a component separate from the housing 1. The outer surfaces of the housing 1 and the plug 6 form a liquid supply passage 7 for supplying liquid to the working space C.

[0061] In this structure, by processing the outer shape of the plug 6, the amount of liquid (refrigerant) supplied to the working space C can be adjusted to prevent the shortage of liquid. Therefore, according to this embodiment, it is possible to provide a compressor 100 that has excellent processability and maintainability of the liquid supply passage 7 and can easily achieve improved cooling performance of the air (gas) in the working space C. In addition, as described above, the shape of the liquid supply passage 7 can be determined by processing the outer shape of the plug 6, so the processing cost can be suppressed compared to the case where the liquid supply passage 7 is formed inside the plug 6. As a result, the manufacturing cost of the compressor 100 can be suppressed.

[0062] (2) The housing 1 has: a bore (storage chamber) 8 for storing the screw rotors 2 and 3; an introduction passage 9 for introducing liquid from the outside of the housing 1; and a communication passage 10 connecting the bore 8 and the introduction passage 9. By arranging the plug 6 in the communication passage 10, a pair of injection flow passages 13 are formed by the front end portion 61 of the plug 6 and the inner surface of the communication passage 10. The liquids injected from the pair of injection flow passages 13 collide with each other in the working space C.

[0063] According to this structure, by making the liquids ejected from the pair of ejection channels 13 collide with each other, the atomized liquid can be diffused widely in the working space C. This is different from the case where the ejected liquids are not collided with each other (see Figure 6 , Figure 7 ) compared to the conventional cooling system, it can improve the cooling performance of the air in the working space C.

[0064] (3) By arranging the plug-in member 6 in the communication passage 10, only a pair of injection flow paths 13 of the present embodiment are formed by a pair of tapered surface portions 63 and a pair of inclined surface portions 10a. A groove 65 capable of injecting liquid (refrigerant) in the form of a liquid film is formed on the tapered surface portion 63. That is, the injection flow path 13 of the present embodiment is a liquid film injection flow path for injecting a liquid film. The liquid films injected from the pair of injection flow paths (liquid film injection flow paths) 13 collide with each other in the working space C.

[0065] According to this structure, the liquid films collide with each other to promote film formation, and the atomized liquid can be spread over a wide range. The surface area (i.e., heat exchange area) of the liquid increases by film formation and atomization of the liquid, so the compressed air in the working space C can be effectively cooled, and the compressor performance can be improved.

[0066] (4) The pair of liquid supply passages 7 includes a pair of liquid supply storage spaces 12 for storing the liquid supplied from the introduction passage 9, and a pair of injection flow passages 13 for injecting 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 the pair of wide surface portions 62 of the plug 6 and the inner surface of the communication passage 10, and the pair of injection flow passages 13 are formed by the pair of tapered surface portions 63 of the plug 6 and the pair of inclined surface portions 10a of the communication passage 10. The flow passage cross-sectional area of ​​the pair of liquid supply storage spaces 12 formed on the upstream side of the pair of injection flow passages 13 is larger than the flow passage cross-sectional area of ​​the pair of injection flow passages 13.

[0067] In this structure, since the liquid supply storage space 12 having a larger flow path cross-sectional area than the injection flow path 13 is formed from the introduction path 9 to the injection flow path 13, it is possible to reduce the pressure loss of the liquid flowing in the liquid supply path 7. As a result, the liquid in a high pressure state can be strongly ejected from the injection opening 11, so that the liquid can be diffused over a wider range.

[0068] (5) The pair of liquid supply passages 7 are formed in a symmetrical shape across the plug-in member 6. Thus, the difference between the pressure of the liquid in the liquid supply passage 7 on the upstream side of the pair of liquid supply passages 7 and the pressure of the liquid in the liquid supply passage 7 on the downstream side of the pair of liquid supply passages 7 can be reduced. Thus, the speed of the liquids respectively ejected from the pair of injection flow passages 13 becomes substantially the same speed, so it is easy to control the collision site between the liquids. In the present embodiment, the liquid films are ejected evenly from the pair of injection flow passages 13, so that the liquid films after the collision extend straightly upward.

[0069] (6) In addition, the flow path cross-sectional shape of the introduction passage 9 is circular, and a circular through hole 66 arranged in the introduction passage 9 is formed in the plug 6. The opening area of ​​the through hole 66 is larger than the flow path cross-sectional area of ​​the introduction passage 9. Assuming that the opening area of ​​the through hole 66 is smaller than the flow path cross-sectional area of ​​the introduction passage 9, the pressure loss of the liquid passing through the through hole 66 becomes larger. As a result, the difference between the pressure of the liquid in the liquid supply passage 7 on the upstream side and the pressure of the liquid in the liquid supply passage 7 on the downstream side becomes larger. In this case, a difference occurs between the speed of the liquid ejected from one of the pair of injection flow paths 13 and the speed of the liquid ejected from the other of the pair of injection flow paths 13, so it becomes difficult to control the collision site between the liquids. In contrast, in the present embodiment, the opening area of ​​the through hole 66 arranged in the introduction passage 9 is larger than the flow path cross-sectional area of ​​the introduction passage 9, so that the pressure loss of the liquid passing through the through hole 66 can be suppressed. This makes it possible to reduce the pressure difference and the speed difference of the liquids ejected from the pair of ejection openings 11 , thereby making it easier to control the collision site between the liquids.

[0070] (7) The jet flow path 13 is formed in such a manner that the angle (collision angle) θ between the jet directions of the liquids jetted from the paired jet flow paths 13 is 30 degrees or more. In the present embodiment, the angle between the extension lines of the pair of jet flow paths 13 is 30 degrees or more. In this structure, the liquid can be effectively atomized and the surface area of ​​the liquid can be expanded compared to the case where the liquids collide with each other at a collision angle θ of less than 30 degrees.

[0071] (8) The communication passage 10 and the bore 8 are connected via the long hole 5 along the axial direction of the screw rotors 2 and 3, and in each of the pair of injection flow passages 13, the front end portion 61 of the plug 6 and the long hole 5 form an injection opening 11 facing the working space C. According to this structure, by adjusting the shape of the long hole 5 and the shape of the front end portion 61 of the plug 6, the shape and opening area of ​​the injection opening 11 can be adjusted.

[0072] <Second Embodiment>

[0073] Reference Figure 8 and Fig. 9 Hereinafter, a plug connector 6B according to a second embodiment of the present invention will be described. In addition, the same reference numerals are given to the same or corresponding structures as those described in the first embodiment, and mainly the different points will be described. Figure 8 It is a perspective view of the plug fitting 6B according to the second embodiment. Fig. 9 is with Figure 5 The same figure is a diagram showing the results of numerical analysis of the liquid ejected from the ejection flow path 13B formed by the plug 6B of the second embodiment.

[0074] The housing 1 of the second embodiment is the same as that of the first embodiment, but the plug 6B of the second embodiment is different from the plug 6 described in the first embodiment. In the first embodiment, a groove 65 is formed on each of the pair of tapered surfaces 63 (see Figure 3 , Figure 4 ). In contrast, in the second embodiment, as Figure 8 As shown, a pair of tapered surface parts 63B are respectively formed with a plurality of grooves 67B extending linearly from the wide surface part 62 to the top (top end) 6Bt of the front end part 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 respectively formed along the direction orthogonal to the axial direction of the screw rotors 2 and 3.

[0075] In the first embodiment, the example in which only a pair of injection flow paths 13 are formed with respect to one plug 6 by arranging the plug 6 in the communication path 10 using a pair of tapered surface portions 63 and a pair of inclined surface portions 10a is described (see Figure 3 , Figure 4 ). In contrast, in the second embodiment, by arranging the plug 6B in the communication passage 10, a plurality of pairs (six pairs in the illustrated example) of injection flow passages 13B are formed with respect to one plug 6B by a plurality of grooves 67B of a pair of tapered surfaces 63B and a pair of inclined surfaces 10a.

[0076] In addition, the injection flow path 13 of the first embodiment is a liquid film injection flow path for injecting a liquid film. In contrast, the injection flow path 13B of the second embodiment is a jet injection flow path for injecting a jet stream. In each of the plurality of pairs of injection flow paths 13B, an injection opening 11B facing the working space C is formed by the top 6Bt of the front end portion 61 of the plug 6B and the long hole 5.

[0077] The jet flows ejected from the plurality of pairs of jet ejection flow paths 13B collide with each other in the working space C.

[0078] Moreover, similarly to the first embodiment, the sum of the flow path cross-sectional areas of the pair of liquid supply storage spaces 12 is larger than the sum of the flow path cross-sectional areas of the pairs of injection flow paths 13 .

[0079] In the second embodiment, a plurality of pairs of jet flow paths (jet jet flow paths) 13B are formed by the outer surfaces of the housing 1 and the plug 6B. The jets jetted from the jet flow paths 13B that form pairs collide with each other in the working space C. Fig. 9As shown, by the collision of the jets, the liquid expands in a fan-shaped manner in the axial direction of the screw rotors 2 and 3, and the surface area of ​​the liquid is increased. Therefore, according to the second embodiment, as in the first embodiment, a compressor 100 can be provided that has excellent processability and maintainability of the liquid supply passage 7 and can easily achieve improved cooling performance for the air (gas) in the working space C.

[0080] <Third Embodiment>

[0081] Reference Figure 10 to Figure 12 Hereinafter, a plug connector 6C according to a third embodiment of the present invention will be described. In addition, the same reference numerals are given to the same or corresponding structures as those described in the second embodiment, and mainly the different points will be described. Fig.10 It is a perspective view of a plug fitting 6C according to the third embodiment. Fig.11 Observed from the XI direction Fig.10 A top view of the plug-in component 6C. Fig.12 is with Figure 5 and Fig. 9 The same figure is a diagram showing the results of numerical analysis of the liquid ejected from the ejection flow path 13C formed by the plug 6C according to the third embodiment.

[0082] 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 Figure 8 ). In contrast, in the third embodiment, as Fig.10 and Fig.11 As shown, the plurality of grooves 67C of the tapered surface portion 63C are formed along directions inclined with respect to the axial direction of the screw rotors 2 , 3 and the direction orthogonal to the axial direction.

[0083] like Fig.11 As shown, in the third embodiment, the extending direction D1 of the slots 67C intersects the axial direction D0 of the screw rotors 2 and 3 and the direction orthogonal to the axial direction D0 (the plane orthogonal to the axial direction D0) in a plan view.

[0084] In the third embodiment, as in the second embodiment, a plurality of pairs of jet flow paths (jet jet flow paths) 13C are formed by the outer surfaces of the housing 1 and the plug 6C, thereby achieving the same effects as in the second embodiment. Moreover, in the third embodiment, the jet flow paths 13C are formed to be inclined relative to the axial direction D0 and the direction orthogonal to the axial direction D0 when viewed from above. Fig.11 and Fig.12 As shown in FIG. 1 , by the collision of the jets, the liquid expands in a fan-shaped manner in a direction orthogonal to the extension direction D1 of the groove 67C, and the surface area of ​​the liquid is increased. According to the third embodiment, by adjusting the angles of the plurality of grooves 67 (the angle between the axial direction D0 and the extension direction D1 of the groove 67C when viewed from above) The liquid injected and collided from the paired injection flow paths 13C can be diffused in the direction along the teeth of the screw rotors 2 and 3 or diffused in the cross section of the teeth.

[0085] <Fourth Embodiment>

[0086] Reference Fig.13 A plug 6D according to a fourth embodiment of the present invention will be described. Note that the same reference numerals are used for the same or corresponding structures as those described in the third embodiment, and mainly the different points will be described. Fig.13 It is a perspective view of a plug fitting 6D according to the fourth embodiment.

[0087] In the fourth embodiment, a groove 68 extending in the axial direction of the screw rotors 2 and 3 is formed at the top (top end) of the front end portion 61 of the plug 6D, which is different from the third embodiment. The groove 68 is formed to expand the liquid supply range in the working space C. In the present embodiment, the groove 68 is formed in a V-shaped cross section that is recessed from the front end side of the front end portion 61 to the base end side.

[0088] In a third embodiment, if Fig.10 As shown in FIG. 1 , the injection opening 11C is open on the upper surface, and a pair of injection flow paths 13C are separated by a partition wall. Fig.13 As shown, the injection opening 11D forms a V-shaped groove 68, and the injection openings 11D that are paired with each other form a space between each other. In the third embodiment, depending on the diffusion conditions after the jet collision, there is a possibility that the diffusion is hindered by the partition wall in the groove 67C to be injected. Different from this, in the plug 6D of the fourth embodiment, by forming a V-shaped groove 68 at the top of the front end 61, the partition wall in the groove 67D to be injected disappears, and the diffusion obstruction after the collision of the jets can be suppressed. That is, according to the fourth embodiment, compared with the third embodiment, the liquid can be diffused in a wider range.

[0089] As described above, in the compressors of the first to fourth embodiments, by combining the outer surfaces of the housing and the plug, one or more injection flow paths are formed in which the injected liquid can collide with each other. Therefore, by simply changing the processing content of one plug provided for one screw rotor and the length in the longitudinal direction (the axial direction of the screw rotors 2 and 3), the cooling performance in the working space C can be improved, and the flow rate of the liquid used for cooling the compressed air can be easily changed.

[0090] <Other Implementation Methods>

[0091] In addition, the present invention is not limited to the above-mentioned embodiments, and includes various modified examples. The above-mentioned embodiments are embodiments described in detail in order to easily explain the present invention, and are not limited to having all the structures described. That is, a part of the structure of a certain embodiment can be replaced with the structure of other embodiments, and in addition, the structure of other embodiments can be added to the structure of a certain embodiment. In addition, for a part of the structure of each embodiment, other structures can also be added, deleted, or replaced.

[0092] In addition, in the above-mentioned embodiment, a twin-rotor type liquid-cooled screw compressor is used as an example, but the present invention can also be applied to screw compressors other than twin-rotor types such as single-rotor type and triple-rotor type. In addition, the gas compressed by the compressor is not limited to air.

[0093] Description of Reference Numerals

[0094] 1 ... housing, 2 ... driving rotor (screw rotor), 3 ... driven rotor (screw rotor), 5 ... long hole, 6, 6B, 6C, 6D ... plug-in fitting, 6t, 6Bt, 6Dt ... top (top end), 7 ... liquid supply passage, 8 ... cavity (storage chamber), 9 ... introduction passage, 10 ... communication passage, 10a ... inclined surface, 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 ...jet flow path (jet jet flow path), 13C...jet flow path (jet jet flow path), 61...front end portion, 62...wide face portion, 63, 63B, 63C...conical face portion, 63a...axial end portion, 64...narrow face portion, 65...groove (recessed portion), 65a...bottom surface (conical 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 room), θ...collision angle.

Claims

1. A liquid-cooled screw compressor that sucks in gas to generate compressed gas, the liquid-cooled screw compressor being characterized by: Helical rotor; a housing that accommodates the helical rotor and forms a working space together with the helical rotor; and A plug-in component, which is a component different from the housing, A liquid supply passage for supplying liquid to the working space is formed by the outer surfaces of the housing and the plug-in component.

2. The liquid-cooled screw compressor according to claim 1, characterized in that: The housing has: a housing chamber for housing the screw rotor; an introduction passage for introducing liquid from the outside of the housing; and a communication passage for connecting the housing chamber with the introduction passage. By arranging the plug in the communication passage, at least one pair of injection flow paths is formed by the front end of the plug and the inner surface of the communication passage. The liquids ejected from the at least one pair of ejection flow paths collide with each other in the working space.

3. The liquid-cooled screw compressor according to claim 2, characterized in that: The plug-in piece has a pair of wide face portions facing each other. The front end of the plug is formed into a tapered shape with a pair of tapered surfaces. The communication passage of the housing has a pair of inclined surface portions facing the pair of tapered surface portions of the plug, A pair of liquid supply passages are formed by the outer surfaces of the housing and the plug-in component. The pair of liquid supply passages comprises: a pair of liquid supply storage spaces, which are formed by the pair of wide surface portions of the plug and the inner surface of the communication passage, and store the liquid supplied from the introduction passage; and One or more injection flow paths are formed by the pair of tapered surfaces of the plug and the pair of inclined surfaces of the communication path, and the liquid in the liquid supply storage space is injected into the working space. The flow path cross-sectional areas of the pair of liquid supply storage spaces are larger than the flow path cross-sectional areas of the pair or more of injection flow paths.

4. The liquid-cooled screw compressor according to claim 3, characterized in that: By arranging the plug in the communication passage, the pair of tapered surface portions and the pair of inclined surface portions form only a pair of the injection flow passages. The injection flow path is a liquid film injection flow path for injecting a liquid film, The liquid films ejected from the pair of liquid film ejection flow paths collide with each other in the working space.

5. The liquid-cooled screw compressor according to claim 3, characterized in that: By arranging the plug in the communication passage, a plurality of pairs of the injection 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 flow path for jetting a jet flow, The jets ejected from the plurality of pairs of jet ejecting channels collide with each other in the working space.

6. The liquid-cooled screw compressor according to claim 5, characterized in that: A plurality of grooves extending linearly from the wide surface to the tip of the front end 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.

7. The liquid-cooled screw compressor according to claim 2, characterized in that: The communication passage and the storage chamber are connected by a long hole along the axial direction of the screw rotor. In each of the one or more injection flow paths, an injection opening facing the working space is formed by the front end portion of the plug and the long hole.

8. The liquid-cooled screw compressor according to claim 2, characterized in that: The injection flow paths are formed so that the injection directions of the liquid injected from the paired injection flow paths form an angle of 30 degrees or more.

9. The liquid-cooled screw compressor according to claim 6, characterized in that: The plurality of grooves are formed along a direction orthogonal to an axial direction of the screw rotor.

10. The liquid-cooled screw compressor according to claim 6, characterized in that: The plurality of grooves are formed along directions that are inclined with respect to the axial direction of the screw rotor and a direction orthogonal to the axial direction.

11. The liquid-cooled screw compressor according to claim 6, characterized in that: A groove extending in the axial direction of the screw rotor is formed at the tip of the front end portion of the plug.

12. The liquid-cooled screw compressor according to claim 3, characterized in that: The pair of liquid supply passages are formed in a symmetrical shape with the plug interposed therebetween.

13. The liquid-cooled screw compressor according to claim 3, characterized in that: The flow path cross-section of the introduction passage is circular. The plug is formed with a circular through hole arranged in the introduction passage. The opening area of ​​the through hole is equal to or larger than the flow path cross-sectional area of ​​the introduction path.

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