Screw compressor

Abstract

To provide a screw compressor that can preferably cool and seal the inside.SOLUTION: A screw compressor 100 includes: a screw rotor 1; a casing 4 for storing the screw rotor 1; and a liquid supply mechanism 16, 41, 42, 43, 31 for supplying liquid from a liquid injection nozzle 31 into a compression chamber 13 formed by the screw rotor 1 in the casing 4, where atomization 30 jetted from the liquid injection nozzle 31 is oriented on a low-pressure side of the compression chamber 13.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] A screw compressor is a device that compresses gases such as air. A screw compressor is a device that generates compressed gas by meshing two rotors, a screw-shaped male rotor and a female rotor. In a screw compressor, in order to increase the gas compression efficiency, a liquid supply mechanism is provided that injects a liquid such as oil into a gas compression chamber formed in a casing that houses the male and female screw rotors. The injected liquid cools the compressed gas by heat exchange with the liquid and seals gaps between the screw rotors and between the screw rotors and the casing to reduce gas leakage.

[0003] A conventional technique for supplying liquid into a gas compression chamber will be described. Patent Document 1 describes a liquid supply mechanism that generates a swirling flow inside the mechanism while injecting the liquid, and when the liquid is injected from a nozzle, breaks the liquid into minute droplets by the centrifugal force generated by the swirling flow.The mechanism cools compressed gas by heat exchange with the minute droplets, and supplies minute droplets to gaps between screw rotors and between the screw rotors and the casing to seal them and reduce gas leakage.

[0004] The regulating device for a gas compressor lubrication system described in Patent Document 2 includes a control device arranged in communication with a temperature sensor and a pressure sensor. The control device then continuously controls the valve mechanism of the liquid supply mechanism in response to a temperature signal from the temperature sensor and a pressure signal from the pressure sensor. This control continuously controls the flow rate of lubricant to the lubricant inlet of the compressor to optimize compressor performance. The control device thereby controls the flow rate of low pressure gas to the compressor in response to the pressure signal. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] US Publication No. 2019 / 0093659A1 [Patent Document 2] Patent No. 3712004 Summary of the Invention [Problem to be solved by the invention]

[0006] In order to cool the compressed gas and reduce gas leakage from the gaps between the screw rotors and between the screw rotor and the casing using the above-mentioned liquid supply mechanism, it is necessary to supply liquid that is suitable for (1) the pressure change and (2) the shape change in the compression chamber from the start to the end of compression. However, the conventional Patent Documents 1 and 2 have the following problems. Regarding issue (1), as the pressure inside the compression chamber increases from low to high, the pressure difference between the injection pressure of the liquid injection nozzle and the pressure inside the compression chamber decreases. As the pressure difference decreases, the flow rate decreases, so on the high-pressure side, the diameter of the liquid injection nozzle must be increased in accordance with the decrease in the pressure difference in order to ensure the same liquid supply flow rate. However, if the diameter of the liquid injection nozzle is increased, the size of the droplets increases, and the liquid becomes less microdropletizable. This reduces the uniform dispersion of the droplets inside the compression chamber, and the compressed gas cannot be sufficiently cooled.

[0007] Regarding issue (2), the spray supplied from the liquid injection nozzle is sprayed isotropically without directionality, so the spray supply cannot be suited to the screw shape of the compression chamber. As a result, the effect of reducing gas leakage from the gaps between the screw rotors and the gaps between the screw rotor and the casing due to the sealing of the liquid droplets cannot be fully obtained.

[0008] The present invention has been made in view of the above circumstances, and has an object to provide a screw compressor in which internal cooling and sealing can be performed satisfactorily. [Means for solving the problem]

[0009] In order to solve the above problems, the screw compressor of the present invention comprises a screw rotor, a casing that houses the screw rotor, and a liquid supply mechanism that supplies liquid from a liquid injection nozzle into a compression chamber formed by the screw rotor within the casing, and the spray injected from the liquid injection nozzle is directed toward the low-pressure side of the compression chamber. Effect of the Invention

[0010] According to the present invention, it is possible to provide a screw compressor in which the inside can be cooled and sealed well. [Brief description of the drawings]

[0011] [Figure 1] 1 is a vertical sectional view of a configuration of a screw compressor according to a first embodiment of the present invention. [Diagram 2] A cross-sectional view of the screw rotor along line II in Figure 1. [Diagram 3] 2 showing the liquid supplying method according to the first embodiment. FIG. [Figure 4] FIG. 4 is a schematic cross-sectional view of the structure of a liquid supply unit of the injection nozzle. [Diagram 5] 5 is a cross-sectional view of a liquid introducing channel to a swirling flow generating portion taken along line III-III in FIG. 4. [Figure 6] FIG. 4 is a cross-sectional view of the swirling flow generating portion taken along line IV-IV in FIG. [Figure 7] Schematic cross-sectional view of the mechanism by which spray has directionality. [Figure 8] FIG. 4 is a schematic cross-sectional view of liquid atomization in a liquid supply section on the low pressure side. [Figure 9] FIG. 4 is a schematic cross-sectional view of liquid atomization in a liquid supply section on a high pressure side. [Figure 10] 2 showing a liquid supplying method according to a second embodiment of the present invention. FIG. [Figure 11] 2 showing a liquid supplying method according to a third embodiment of the present invention. FIG. [Figure 12] 2, showing a liquid supplying method according to a fourth embodiment of the present invention. FIG. [Figure 13]2 showing a liquid supplying method according to a fifth embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a liquid supply mechanism for a screw compressor according to the present invention will be described with reference to the drawings. In each drawing, the same elements are denoted by the same reference numerals, and duplicated explanations are omitted. The present invention is not limited to each embodiment described below, and includes various modified examples. For example, the embodiment described below is described in detail to easily explain the present invention, and is not necessarily limited to those including all the configurations. In addition, it is possible to replace a 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. In addition, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

[0013] <<First embodiment>> Fig. 1 shows a schematic vertical cross-sectional view of a screw compressor 100 according to a first embodiment of the present invention. Fig. 2 shows a cross-sectional view of a screw rotor 1 taken along line II in Fig. 1. The screw compressor 100 according to the first embodiment is a device that compresses a gas such as air. The screw compressor 100 includes a screw rotor 1 (2, 3) that compresses gas, and a casing 4 that houses the screw rotor 1. The screw rotor 1 has a male rotor 2 and a female rotor 3. The male rotor 2 and female rotor 3 have screw-shaped twisted teeth (lobes) and rotate while meshing with each other. The male rotor 2 and female rotor 3 are collectively referred to as the screw rotor 1.

[0014] The screw compressor 100 includes a suction side bearing 5 and a discharge side bearing 6. The suction side bearing 5 and the discharge side bearing 6 support the male rotor 2 and the female rotor 3, respectively, so that they are free to rotate. A shaft seal component 7 such as an oil seal, a mechanical seal, or the like is provided at the lower end of the casing 4. The shaft seal component 7 provides a seal between the casing 4 and the rotor shaft J. Here, the "suction side" refers to the side where a gas such as air is suctioned in the rotor axis J direction of the screw rotor 1 (the side of the suction port 14 of the casing 4). The "discharge side" refers to the side where a gas is discharged in the axial direction of the screw rotor 1 (the side of the discharge port 15).

[0015] <Male rotor 2 and female rotor 3> The male rotor 2 has a suction side end 2t connected via a rotor shaft J to a motor 8 which is a rotation drive source.

[0016] As shown in Fig. 2, a cylindrical male side bore 9 that covers the male rotor 2 and a cylindrical female side bore 10 that covers the female rotor 3 are formed on the inner surface of the casing 4. The male rotor 2 and the female rotor 3 are housed in the casing 4 with a gap of several tens to several hundreds of µm from the male side bore 9 and the female side bore 10 of the casing 4, respectively. There are two intersection lines between the male side bore 9 and the female side bore 10. The intersection line on the low pressure side is defined as the suction side cusp (suction side intersection line) 11, and the intersection line on the high pressure side is defined as the compression side cusp (compression side intersection line) 12.

[0017] The male rotor 2, which is rotationally driven by a motor 8 (arrow α13 in FIG. 2), meshes with the female rotor 3 to rotate the female rotor 3 (arrow α14 in FIG. 2). The compression chamber 13 formed by the tooth grooves 2m of the male rotor 2 and the tooth grooves 3m of the female rotor 3 and the male bore 9 and female bore 10 surrounding them shown in Fig. 2 expands and contracts due to the rotation of the male rotor 2 and the female rotor 3 (arrows α13, α14 in Fig. 2). Due to the rotation of the male rotor 2 and the female rotor 3, as shown in Fig. 1, gas such as air is sucked in from the suction port 14 (arrow α11 in Fig. 1). The sucked in gas is compressed to a predetermined pressure and then discharged from the discharge port 15 (arrow α12 in Fig. 1).

[0018] Also, liquid is injected from the outside of the screw compressor 100 into the compression chamber 13 (see FIG. 2), the suction side bearing 5, the discharge side bearing 6, and the shaft seal component 7 through the liquid supply hole 16, the suction side bearing liquid supply hole 17, and the discharge side bearing liquid supply hole 18. The liquid serves to lubricate and seal, and is oil in most cases. The liquid serves the roles of lubricating and sealing between the male rotor 2 and the female rotor 3, lubricating and sealing between the screw rotor 1 (2, 3) and the inner wall of the casing 4, lubricating and sealing between the shaft seal parts 7 and the rotor shaft J, and lubricating the suction side bearing 5 and the discharge side bearing 6.

[0019] <Liquid supply method> FIG. 3 shows a view of the screw rotor 1 of the liquid supplying method of the first embodiment, taken along the line II in FIG. A method of supplying liquid to the compression chamber 13 in the first embodiment will be described.

[0020] Arrow α21 in Figure 3 indicates the direction of movement of ridge line 26 of male rotor 2 and ridge line 27 of female rotor 3. In other words, it indicates the direction of travel of gas carried by male rotor 2 and female rotor 3. The pressure in compression chamber 13 (see Figure 2) increases with the movement of ridge lines 26, 27, i.e., the movement of gas. In other words, the upper downstream side in Figure 3 is the low pressure side, and the lower upstream side is the high pressure side. Incidentally, in the compression chamber 13 (see FIG. 2), in order to cool the air (hereinafter, air will be used as an example of gas) in the compression chamber 13 and to seal each gap (the gap between the male rotor 2 and the female rotor 3, and the gap between the screw rotor 1 (2, 3) and the inner wall of the casing 4), a spray 30 of liquid (mostly oil) in an atomized state is injected from an injection nozzle 31. The reason for turning the liquid (mostly oil) into a spray 30 is to supply the liquid (mostly oil) evenly and widely throughout the space within the casing 4.

[0021] A feature of this embodiment (invention) is that the spray 30 is injected onto the low pressure side of the compression chamber 13. This causes the droplets of the spray 30 to spread from the low pressure side to the high pressure side, lengthening the time they stay in the compression chamber 13. This improves the cooling and sealing properties of the space inside the casing 4, making it possible to improve the compression efficiency of the air (gas).

[0022] Also, in FIG. 3, the spray 30 sprayed from the liquid injection nozzle 31 (31a, 31b, 31c) is directed in a direction perpendicular to the male side ridge 26 and the female side ridge 27 of the screw rotor 1 (the direction of the spray 30 is the low pressure side of the compression chamber 13).

[0023] 4 shows a schematic cross-sectional view of the structure of the liquid supply portion of the injection nozzle 31 (31a, 31b, 31c). The arrows in FIG. 4 indicate the flow of the liquid. The spray 30 is formed by centrifugal force in the liquid injection nozzles 31 (31a, 31b, 31c). Therefore, the central axis 31o (see FIG. 4) of the liquid injection nozzles 31 (31a, 31b, 31c) is tilted to provide directionality.

[0024] 3, by directing the spray 30 in a direction perpendicular to the male ridge line 26 and the female ridge line 27 of the screw rotor 1 (giving directionality), the spray 30 spreads evenly to the left and right from the line perpendicular to the male ridge line 26 and the female ridge line 27. This makes it possible to supply the spray in accordance with the spatial shape of the inclined compression chamber 13, which is unique to the screw compressor 100.

[0025] <Liquid injection nozzle 31 from the low pressure side to the high pressure side of the compression chamber 13> Another feature of this embodiment (invention) is that the nozzle hole diameter Φ (see FIG. 9) of the liquid injection nozzle 31 (31a, 31b, 31c) is increased from the low pressure side to the high pressure side of the compression chamber 13, and the swirling flow in the nozzle hole is strengthened (pressure is increased). The nozzle hole diameter Φ of the injection nozzle 31 shown in FIG. 3 is larger on the high pressure side (see FIG. 9) than on the low pressure side (see FIG. 8). This is because, in the past, there was a problem that the pressure difference with the liquid supply pressure of the liquid injection nozzle becomes smaller on the high pressure side of the compression chamber, resulting in a decrease in the liquid supply flow rate. Note that in FIG. 3, the cross section of the nozzle hole is elliptical, but this is because the nozzle hole is obliquely oriented (inclined toward the low pressure side).

[0026] Therefore, in this embodiment (invention), the injection hole diameter of the injection nozzle 31 is increased from the low pressure side to the high pressure side, thereby increasing the amount of spray 30 on the high pressure side. This makes it possible to prevent a decrease in the liquid supply flow rate on the high pressure side of the compression chamber 13. In the conventional configuration, when the injection nozzle has a larger injection hole diameter, the amount of liquid increases, which reduces the atomization of the liquid, resulting in a problem of reduced cooling and sealing properties. Therefore, in this embodiment (invention), the swirling flow in the liquid injection hole of the injection nozzle 31 (31a, 31b, 31c) on the high pressure side is made stronger than that on the low pressure side. By making the swirling flow in the liquid injection hole of the injection nozzle 31 (31a, 31b, 31c) stronger, it is possible to prevent a decrease in atomization of the liquid even if the injection hole diameter Φ of the injection nozzle 31 (31a, 31b, 31c) is increased.

[0027] <Structure of the liquid supply mechanism including the jet nozzle 31 that strengthens the swirling flow> Using Figures 4 to 9, we will explain the structure of the liquid supply mechanism that increases the injection hole diameter Φ (see Figure 4) of the injection nozzle 31 (31a, 31b, 31c) from the low-pressure side to the high-pressure side of the compression chamber 13 and strengthens the swirling flow within the injection hole (inside the injection nozzle 31).

[0028] Liquid supplied from oil supply hole 16 shown in Fig. 4 passes through liquid introduction flow path 41 (see Fig. 5) and flows into swirling flow generating section 42 (see Fig. 6). Fig. 5 shows a cross-sectional view of liquid introduction flow path 41 into swirling flow generating section 42 taken along line III-III in Fig. 4. The liquid introduction flow path 41 is divided into two flow paths by a flow path separation wall 41r. The liquid introduction flow path 41 has a peripheral wall 41k having a curvature.

[0029] FIG. 6 shows a cross-sectional view of the swirl flow generating portion 42 taken along line IV-IV in FIG. The swirling flow generating section 42 has two connection regions 42s that connect to the liquid introduction flow paths 41 of the two flow paths (see FIG. 5). The swirling flow generating section 42 is formed in a spiral shape so as to generate a swirling flow around the injection nozzle orifice 44 (see FIG. 6 and FIG. 4). A swirling flow 43 (see FIG. 4) generated in the swirling flow generating section 42 passes through an injection nozzle orifice 44, and is then injected from an injection nozzle outlet 45 into a buffer space 46 in the casing inner wall 4n.

[0030] The liquid injected into the buffer space 46 first forms an umbrella-shaped liquid film 47. Then, the tip of the liquid film 47 splits into a liquid filament 48, and then the liquid filament 48 splits to generate fine droplets 49 (spray 30). In this way, by forming a swirling flow 43 (see FIG. 4) in the liquid injection nozzle 31 (31a, 31b, 31c), it is possible to form fine atomized droplets 49 (spray 30) at a short distance from the liquid injection nozzle outlet 45.

[0031] <Directivity of spray 30> In the liquid injection nozzle 31 shown in Fig. 4, the central axis 31o of the injection nozzle 31 (31a, 31b, 31c) is inclined by θ with respect to the swirl central axis 51 of the swirl flow generating section 42, which is a swirl chamber that forms the swirl flow 43. By adjusting the inclination θ of the central axis 31o of the liquid injection nozzle 31 (31a, 31b, 31c), the umbrella-shaped liquid film 47 becomes asymmetric, and the direction of the spray 30 can be made directional. In this way, by adjusting the shape of the liquid injection nozzle 31 (31a, 31b, 31c), it is possible to direct the direction of the spray 30 toward the low-pressure side of the compression chamber 13, as shown in Fig. 3.

[0032] FIG. 7 shows a schematic cross-sectional view of the mechanism by which the spray 30 has directionality. The mechanism by which the spray 30 has directionality (see FIG. 3) will be described. In FIG. 7, the outlet surface 31d of the injection nozzle 31 (31a, 31b, 31c) is not perpendicular to the central axis 31o of the liquid injection nozzle 31 (31a, 31b, 31c), but has a height dimension 53 in the direction of the central axis 31o. At the outlet of the liquid injection nozzle 31, the swirling flow 43 in the injection nozzle 31 is formed in the same manner up to the swirling flow 54, but within the range of the height dimension 53, the swirling flow 43 in the injection nozzle 31 (31a, 31b, 31c) is formed only on the right side of Fig. 7. Therefore, the swirling flow is stronger on the right side than on the left side of Fig. 7, and the centrifugal force acting on the umbrella-shaped liquid film 47 is also larger. As a result, it is possible to form a spray 30 that is directional to the right side of Fig. 7.

[0033] <Liquid supply mechanism for strengthening the swirl flow 43 in the injection hole of the injection nozzle 31> FIG. 8 shows a schematic cross-sectional view of liquid atomization in the liquid supply section (jet nozzle 31) on the low pressure side. FIG. 9 shows a schematic cross-sectional view of the liquid atomization in the liquid supply section (jet nozzle 31) on the high pressure side.

[0034] Using Figures 8 and 9, we will explain the structure of the liquid supply mechanism that strengthens the swirling flow 43 in the injection hole of the injection nozzle 31 (31a, 31b, 31c) from the low pressure side (Figure 8) to the high pressure side (Figure 9) of the compression chamber 13.

[0035] Fig. 8 shows the structure where swirling flow 43 is generated on the low pressure side, and Fig. 9 shows the structure where swirling flow 43 is generated on the high pressure side. In Fig. 9 on the high pressure side, not only is the injection nozzle orifice 44's nozzle hole diameter Φ larger than in Fig. 8 on the low pressure side, but the size of the swirling flow generating section 42 is also larger. By strengthening the swirling flow 43, the centrifugal force is strengthened, making it possible to thin the umbrella-shaped liquid film 47. As a result, even if the injection hole diameter Φ is increased to maintain the liquid flow rate on the high pressure side, the stronger centrifugal force makes it possible to maintain the atomization of the liquid.

[0036] <<Second embodiment>> FIG. 10 shows a liquid supplying method according to a second embodiment of the present invention, as viewed in the direction of an arrow I in FIG. A liquid supply mechanism of the screw compressor 100A according to the second embodiment will be described. The second embodiment is an example in which a liquid supply mechanism provided from the low pressure side to the high pressure side of the compression chamber 13 is provided at an intermediate position between the male rotor 2 and the female rotor 3. Other configurations are the same as those in the first embodiment, so the same components are denoted by the same reference numerals and detailed description thereof is omitted.

[0037] In the second embodiment, the spray 30 injected from the liquid injection nozzle 31A (31a1, 31b1, 31c1) is directed parallel to the compression side cusp 12 of the compression side intersection line and toward the low pressure side (upper side in FIG. 10), so that the spray 30 is supplied to the compression chamber 13. Therefore, it is possible to improve the cooling and sealing performance of the compression chamber 13 by the liquid of the spray 30. In addition, by directing the spray 30 parallel to the compression side cusp 12 of the compression side intersection line and toward the low pressure side (upper side in FIG. 10), the spray 30 can be distributed evenly to the male rotor 2 and the female rotor 3.

[0038] <<Third embodiment>> FIG. 11 shows a liquid supplying method according to a third embodiment of the present invention, as viewed in the direction of the arrow II in FIG. A liquid supply mechanism of a screw compressor 100B according to the third embodiment will be described. In the third embodiment, the liquid injection nozzles 31A (31a1, 31b1, 31c1) that inject spray 30 from the high pressure side toward the low pressure side of the compression chamber 13 in the first embodiment shown in Figure 3 are arranged in a staggered or alternating pattern as shown in Figure 11, rather than being arranged in a straight line, as liquid injection nozzles 31B (31a2, 31b2, 31c2).

[0039] By arranging the ejection positions of the sprays 30 in a staggered or alternating manner, overlapping of the supply areas of the respective sprays 30 is prevented, and the sprays 30 can be supplied uniformly over a wider area.

[0040] <<Fourth embodiment>> FIG. 12 shows a liquid supplying method according to a third embodiment of the present invention, as viewed in the direction of the arrow II in FIG. A liquid supply mechanism of a screw compressor 100C according to the fourth embodiment will be described. In the fourth embodiment, the directions of the sprays 30 sprayed from the liquid injection nozzles 31C (31a3, 31b3, 31c3) are arranged in a staggered or alternating manner based on the perpendicular directions of the ridge lines 26 of the male rotor 2 and the ridge lines 27 of the female rotor 3. The other configurations are similar to those of the first embodiment. Similar components are denoted by the same reference numerals and detailed explanations are omitted.

[0041] By arranging the directions of the sprays 30 in a staggered or alternating manner, overlapping of the supply areas of the sprays 30 from the liquid injection nozzles 31a3, 31b3, and 31c3 is prevented or suppressed, making it possible to supply the sprays 30 more uniformly over a wider area.

[0042] <<Fifth embodiment>> FIG. 13 shows a liquid supplying method according to a fifth embodiment of the present invention, as viewed in the direction of the arrow II in FIG. A liquid supply mechanism of a screw compressor 100D according to the fifth embodiment will be described. In the fifth embodiment, the directions of sprays 30 from a liquid supply mechanism provided from the low pressure side to the high pressure side of a compression chamber 13 are arranged in a staggered or alternating manner. When the rotation speed of the screw rotor 1 is low, the effect of the shape of the oblique compression chambers 13 (see FIG. 2), which is specific to the screw compressor 100D, becomes smaller.

[0043] In some cases, it may be better to spray in a direction from a low pressure region to a high pressure region, rather than spraying in a direction perpendicular to rotor ridges 26, 27 in accordance with the shape of oblique compression chamber 13 (see FIG. 2). The spraying method shown in FIG. 13 prevents or suppresses overlapping of the supply areas of the sprays 30 sprayed from the liquid spray nozzles 31D (31a4, 31b4, 31c4), making it possible to supply the spray uniformly over a wider area.

[0044] By combining the above-mentioned Figs. 3, 10, 11, 12 and 13, it becomes possible to supply a liquid (oil or the like) more suitable for the operating state of the screw compressors 100 to 100D. As a result, it is possible to supply liquid appropriate to the pressure changes and shape changes within compression chamber 13 from the start of compression to the end of compression, thereby cooling the compressed gas and reducing gas leakage from gaps in various parts.

[0045] <<Other embodiments>> 1. The present invention is not limited to the configuration of the above-described embodiment, and various modifications and specific forms are possible within the scope of the appended claims. [Explanation of symbols]

[0046] 1 Screw rotor 2 Male rotor (screw rotor) 3 Female rotor (screw rotor) 4 Casing 13 Compression chamber (female side) 19 Direction of progress of the ridge of the screw rotor 26 Male rotor ridge (ridge) 27 Female rotor ridge (ridge) 30 spray 31 Liquid injection nozzle (liquid supply mechanism) 31A, 31a1, 31b1, 31c1 Liquid injection nozzles (liquid supply mechanism) facing alternately with respect to the direction of travel of the ridge of the screw rotor 31B, 31a2, 31b2, 31c2 Liquid injection nozzles (liquid supply mechanism) facing in a direction perpendicular to the ridge of the screw rotor 31C, 31a3, 31b3, 31c3 Liquid injection nozzles (liquid supply mechanism) facing in a direction perpendicular to the ridge of the screw rotor 31D, 31a4, 31b4, 31c4 Liquid injection nozzles (liquid supply mechanism) facing alternately with respect to the direction of travel of the ridge of the screw rotor 41 Liquid introduction flow path (liquid supply mechanism) 42 Swirling flow generation part (liquid supply mechanism) 43 Swirling flow inside the injection nozzle (swirling flow) 44 Injection nozzle orifice (liquid supply mechanism) 45 Injection nozzle outlet 47 Umbrella-shaped liquid film (liquid) 48 Liquid Thread (Liquid) 49 Fine droplet (liquid) θ Inclination of the central axis of the liquid injection nozzle relative to the central axis of the swirl chamber 51 Swirling chamber rotation center axis Φ Nozzle hole diameter (nozzle hole diameter) 54 Swirling flow at the exit of a liquid injection nozzle (swirl flow) 55 Swirling flow at the outlet of the liquid injection nozzle at height dimension 53 (swirl flow) 100, 100A, 100B, 100C, 100D Screw Compressor

Claims

1. A screw rotor, a casing for housing the screw rotor, and a plurality of liquid supply mechanisms for supplying liquid from a liquid injection nozzle into a compression chamber formed by the screw rotor in the casing, wherein the liquid supply mechanism forms a swirling flow in the liquid injection nozzle, and the liquid injection nozzle increases the diameter of the injection holes of the liquid injection nozzle and strengthens the swirling flow in the liquid injection nozzle from the low-pressure side to the high-pressure side of the compression chamber characterizing a screw compressor.

2. In the screw compressor according to Claim 1, the spray injected from the liquid injection nozzle is directed in a direction perpendicular to the ridge line of the screw rotor characterizing a screw compressor.

3. In the screw compressor according to Claim 1, the sprays injected from the liquid injection nozzle are alternately directed with respect to the direction perpendicular to the ridge line of the screw rotor characterizing a screw compressor.

4. In the screw compressor according to Claim 1, the sprays injected from the liquid injection nozzle are alternately directed with respect to the advancing direction of the ridge line of the screw rotor characterizing a screw compressor.

5. In the screw compressor according to Claim 1, the spray injected from the liquid injection nozzle is directed toward the low-pressure side of the compression chamber characterizing a screw compressor.

6. A screw rotor, a casing for housing the screw rotor, and a liquid supply mechanism for supplying liquid from a liquid injection nozzle into a compression chamber formed by the screw rotor in the casing, wherein the liquid supply mechanism directs the spray injected from the liquid injection nozzle toward the high-pressure side of the compression chamber and alternately directs it with respect to the advancing direction of the ridge line of the screw rotor characterizing a screw compressor.

7. In the screw compressor according to Claim 1 or Claim 5, the liquid supply mechanism has the central axis of the liquid injection nozzle inclined with respect to the central axis of rotation of the swirl chamber forming the swirling flow characterizing a screw compressor.

8. A screw rotor, a casing for housing the screw rotor, and a liquid supply mechanism for supplying liquid from a liquid injection nozzle into a compression chamber formed by the screw rotor in the casing, Direct the spray ejected from the liquid injection nozzle toward the low-pressure side of the compression chamber. Direct the sprays ejected from the liquid injection nozzle alternately with respect to the direction orthogonal to the ridge line of the screw rotor. A screw compressor characterized by the above.

9. A screw rotor, A casing that houses the screw rotor, A liquid supply mechanism that supplies liquid from a liquid injection nozzle into a compression chamber formed by the screw rotor within the casing, Direct the spray ejected from the liquid injection nozzle toward the low-pressure side of the compression chamber. Direct the sprays ejected from the liquid injection nozzle alternately with respect to the traveling direction of the ridge line of the screw rotor. A screw compressor characterized by the above.

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