Screw compressor, gas compressor system, and liquid supply method for screw compressor

Abstract

To provide a screw compressor, etc. that can be operated in consideration of both compression efficiency and maintenance efficiency in relation to formation of fine droplets of liquid to be supplied to an operation chamber in a compressor body.SOLUTION: A screw compressor 100 comprises a compressor body 1 including a casing 4 comprising a liquid supply mechanism 60 for injecting liquid into a housing chamber 45, and a liquid supply system 80 for recovering the liquid contained in compressed gas discharged by the compressor body 1, and supplying it to the liquid supply mechanism 60 of the casing 4. The liquid supply mechanism 60 includes a swirl flow generator 62 located on the upstream side of an injection hole 61 opened in the housing chamber 45, and for generating a swirl flow by swirling the liquid supplied from the liquid supply system 80. The liquid supply mechanism 60 or the liquid supply system 80 includes a swirl adjustment device 63 for adjusting the amount of swirling of the swirl flow generated by the swirl flow generator 62.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a screw compressor, a gas compressor system, and a liquid supply method for a screw compressor, and more particularly to a liquid supply type screw compressor in which liquid is supplied to the inside of a compressor body, a gas compressor system including a plurality of liquid supply type screw compressors, and a liquid supply method for a screw compressor in which liquid is supplied to the inside of a compressor body. [Background technology]

[0002] A screw compressor is a device that compresses gases such as air. The compressor body of a screw compressor includes a screw rotor with twisted teeth and a casing that houses the screw rotor. The volume of a working chamber formed by the teeth of the screw rotor and the inner wall surface of the casing increases and decreases as the screw rotor rotates, thereby compressing the gas. Some screw compressors are of a liquid-feed type, in which a liquid such as oil or water is supplied to the working chamber within the compressor body to increase the gas compression efficiency. The liquid supplied to the inside of the compressor body serves to cool the compressed gas within the working chamber through heat exchange, reduce leakage of compressed gas through gaps between the screw rotor and the casing, and lubricate the screw rotor.

[0003] As a liquid-feed type screw compressor, for example, one that supplies atomized liquid into the working chamber has been proposed (see, for example, Patent Document 1). In the screw compressor described in Patent Document 1, a swirling flow of lubricating liquid (liquid) is generated in a lubrication port of a casing that communicates with the working chamber, and the swirling flow of lubricating liquid is injected into the working chamber. In this case, the centrifugal force generated by the swirling flow breaks the lubricating liquid into fine droplets that are dispersed within the working chamber.

[0004] Also, among liquid-feed screw compressors, those that control the flow rate and temperature of the liquid supplied to the inside of the compressor body (working chamber) are known (see, for example, Patent Document 2). The adjusting device for a gas compressor lubrication system described in Patent Document 2 includes a valve mechanism that adjusts the flow rate of the lubricant (liquid) leading to the lubricant inlet of the compressor, and a control device that is arranged in communication with a first temperature sensor that measures the compressor discharge temperature and a pressure sensor that measures the compressor discharge pressure. The control device constantly controls the valve mechanism in response to the temperature signal from the first temperature sensor and the pressure signal from the pressure sensor, thereby constantly controlling the flow rate of the lubricant (liquid) to optimize compressor performance, and also controls the flow rate of low-pressure gas leading to the compressor in response to the pressure signal from the pressure sensor. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] US Patent Application Publication No. 2018 / 1234567 [Patent Document 2] Special Publication No. 8-500884 Summary of the Invention [Problem to be solved by the invention]

[0006] In the screw compressor described in Patent Document 1, the liquid supplied to the working chamber is broken down into microdroplets, thereby increasing the total surface area of ​​the droplets and improving the cooling effect on the compressed gas. This improves the compression efficiency of the screw compressor. However, when the liquid supplied to the working chamber is oil, an increase in the total surface area of ​​the droplets accelerates oil degradation due to oxidation. As the oil deteriorates, the state of the oil's microdropletization changes. Furthermore, if the oil deteriorates too quickly, the interval between maintenance tasks such as oil changes becomes shorter. In particular, in a gas compressor system that generates compressed gas using multiple screw compressors, if the degree of oil deterioration differs between each screw compressor, there is a concern that it will be impossible to standardize the maintenance schedule for each screw compressor. If the maintenance schedules for each screw compressor differ, the maintenance work hours and costs increase and maintenance efficiency decreases.

[0007] Thus, in a liquid feed screw compressor and a gas compressor system including a plurality of such compressors, it is important to adjust the formation of fine droplets of the liquid supplied to the working chamber so as to achieve an optimal balance between the compression efficiency and maintenance efficiency of the screw compressor. However, Patent Document 2 does not describe or suggest anything about control from this perspective.

[0008] The present invention has been made to solve the above problems, and its object is to provide a screw compressor, a gas compressor system, and a liquid supply method for a screw compressor that can be operated in consideration of both the compression efficiency and maintenance efficiency of the screw compressor when turning the liquid to be supplied to the working chamber into fine droplets. [Means for solving the problem]

[0009] The present application includes a plurality of means for solving the above problems, and one example thereof is a screw rotor and a storage chamber for rotatably storing the screw rotor. With a liquid supply mechanism for injecting liquid into the storage chamber; was establishedand a liquid supply system that recovers liquid contained in compressed gas discharged from the compressor body and supplies the liquid to the liquid supply mechanism of the casing, the liquid supply mechanism including a jet hole that opens into the storage chamber and a swirl flow generator that is located upstream of the jet hole and swirls the liquid supplied from the liquid supply system to generate a swirl flow. The structure is a swirl adjusting device for adjusting the amount of swirl of the swirl flow generated by the swirl flow generator. The swirl adjustment device is arranged upstream of the swirl flow generator and includes a rotatable swirl adjustment member having an opening that opens into the flow path of the swirl flow generator, and the swirl adjustment member is configured so that the opening state of the opening relative to the flow path of the swirl flow generator changes according to a change in the rotation angle. . [Effects of the Invention]

[0010] According to the present invention, by adjusting the amount of swirl of the swirl flow generated by the swirl flow generator using the swirl adjustment device, it is possible to adjust the droplet size of the liquid generated by the liquid supply mechanism. Therefore, it is possible to operate the screw compressor in consideration of both the compression efficiency and maintenance efficiency when turning the liquid into fine droplets to be supplied to the working chamber in the compressor body. Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram showing the configuration of a screw compressor according to a first embodiment of the present invention. [Figure 2] 2 is a cross-sectional view of the screw compressor according to the first embodiment shown in FIG. 1, taken along the line II-II. [Figure 3] FIG. 2 is an enlarged cross-sectional view showing a liquid supply mechanism of the screw compressor according to the first embodiment. [Figure 4] 4 is a cross-sectional view of a swirl flow generator, which is part of the liquid supply mechanism of the screw compressor according to the first embodiment shown in FIG. 3, as viewed from the arrows IV-IV. [Figure 5] 4 is a cross-sectional view of a rotation adjustment member, which is a part of the liquid supply mechanism of the screw compressor according to the first embodiment shown in FIG. 3, as viewed in the direction of arrows VV. [Figure 6] FIG. 4 is a cross-sectional view showing a rotation adjustment member of a screw compressor according to a first modified example of the first embodiment. [Figure 7] 7 is a characteristic diagram showing an example of the relationship between the rotation angle of the swirl adjustment member according to the first modified example shown in FIG. 6 and the opening area relative to the swirl flow generator. FIG. [Figure 8] FIG. 7 is an explanatory diagram showing the function of the swirl adjustment member according to the first modified example shown in FIG. 6, and is a diagram showing the opening state of the swirl adjustment member according to the first modified example relative to the swirl flow generator when the swirl adjustment member is at a certain rotation angle. [Figure 9] 8 is a diagram showing an opening state relative to the swirl flow generator when the swirl adjustment member according to the first modified example shown in FIG. 6 is at a rotation angle different from that shown in FIG. 7. [Figure 10] FIG. 10 is a cross-sectional view showing a rotation adjustment member of a screw compressor according to a second modified example of the first embodiment. [Figure 11] 11 is a characteristic diagram showing an example of the relationship between the rotation angle of the swirl adjustment member according to the second modified example shown in FIG. 10 and the opening area relative to the swirl flow generator. FIG. [Figure 12] 11 is an explanatory diagram showing the function of the swirl adjustment member according to the second modified example shown in FIG. 10, and is a diagram showing the opening state of the swirl adjustment member according to the second modified example relative to the swirl flow generator when the swirl adjustment member is at a certain rotation angle. [Figure 13] 12. FIG. 14 is a diagram showing an opening state relative to the swirl flow generator when the swirl adjustment member according to the second modified example shown in FIG. 10 is at a rotation angle different from that shown in FIG. [Figure 14] FIG. 10 is a characteristic diagram used to control the rotation adjustment device in the screw compressors according to the first embodiment and the first to second modified examples, showing an example of the relationship between the viscosity of the liquid supplied to the liquid supply mechanism and the droplet diameter of the liquid generated by the injection of the liquid supply mechanism. [Figure 15] FIG. 1 is a characteristic diagram used to control the swirl adjustment device in the screw compressors according to the first embodiment and the first to second modified examples, showing an example of the relationship between the swirl amount (swirl strength) of the swirl flow generated by the liquid supply mechanism and the droplet diameter of the liquid generated by the injection of the liquid supply mechanism. [Figure 16] FIG. 1 is a characteristic diagram used to control the swirl adjustment device in the screw compressors according to the first embodiment and the first to second modified examples, showing an example of the relationship between the swirl amount (strength of swirl) of the swirl flow generated by the liquid supply mechanism and the rotation angle of the swirl adjustment member. [Figure 17] FIG. 4 is a diagram showing the configuration of a screw compressor according to a second embodiment of the present invention. [Figure 18] FIG. 10 is a characteristic diagram used to control a swirl adjustment device (pump or control valve) in a screw compressor according to a second embodiment, showing an example of the relationship between the amount of swirl (strength of swirl) of the swirl flow generated in the liquid supply mechanism and the pressure of the liquid supplied to the liquid supply mechanism. [Figure 19] 1 is a block diagram showing a configuration of a gas compressor system including a plurality of screw compressors according to an embodiment of the present invention. [Figure 20] 20 is a flowchart showing an example of a control procedure of the monitoring device of the gas compressor system shown in FIG. 19. [Figure 21] FIG. 20 is a characteristic diagram used by the monitoring device of the gas compressor system shown in FIG. 19, showing an example of the relationship between the compression efficiency in each screw compressor and the viscosity of the liquid supplied to the liquid supply mechanism. [Figure 22] FIG. 20 is a characteristic diagram used by the monitoring device of the gas compressor system shown in FIG. 19, showing an example of the relationship between the viscosity of the liquid supplied to the liquid supply mechanism in each screw compressor and the diameter of droplets generated by injection from the liquid supply mechanism. [Figure 23] FIG. 20 is a characteristic diagram used by the monitoring device of the gas compressor system shown in FIG. 19, showing an example of the relationship between the diameter of droplets generated by injection from the liquid supply mechanism in each screw compressor and the amount of swirl of the swirling flow generated by the liquid supply mechanism. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of a screw compressor, a gas compressor system, and a liquid supply method for a screw compressor according to the present invention will be described with reference to the drawings. In this description, a twin-rotor screw compressor will be used as an example. However, the present invention can also be applied to a single-rotor screw compressor or a screw compressor having three or more screw rotors. [First embodiment] The configuration of a screw compressor according to a first embodiment will be described with reference to Figs. 1 and 2. Fig. 1 is a diagram showing the configuration of a screw compressor according to a first embodiment of the present invention. Fig. 2 is a cross-sectional view of the screw compressor according to the first embodiment shown in Fig. 1, as viewed from the arrows II-II. In Fig. 1, the lower side is the suction side of the compressor body, and the upper side is the discharge side. Here, the "suction side" refers to the side of the compressor body that sucks in gas in the axial direction, and the "discharge side" refers to the side of the compressor body that discharges gas in the axial direction. In Fig. 2, the thick arrow indicates the rotation direction of the screw rotor.

[0013] 1, the screw compressor 100 is of a liquid feed type and includes a compressor body 1 that compresses gas, a drive source 70 that drives the compressor body 1, and a liquid feed system 80 that recovers liquid contained in the compressed gas discharged by the compressor body 1 and supplies the liquid to the compressor body 1. The drive source 70 is, for example, configured by an electric motor. The screw compressor 100 further includes a control device 90 that controls the driving of the compressor body 1.

[0014] 1 and 2, the compressor body 1 includes a male rotor 2 and a female rotor 3 as a pair of screw rotors that rotate in mesh with each other, and a casing 4 that rotatably houses both the male and female rotors 2, 3. The male rotor 2 is rotatably supported on both axial sides by a suction-side bearing 6 and a discharge-side bearing 7. Like the male rotor 2, the female rotor 3 is rotatably supported on both axial sides by a suction-side bearing and a discharge-side bearing (neither of which are shown).

[0015] The male rotor 2 is composed of a rotor tooth portion 21 having a plurality of twisted teeth (lobes) 21a, and a suction-side shaft portion 22 and a discharge-side shaft portion 23 provided on both axial ends of the rotor tooth portion 21. The rotor tooth portion 21 has a suction-side end face 21b and a discharge-side end face 21c at one axial end (lower end in FIG. 1) and the other axial end (upper end in FIG. 1), respectively. Tooth grooves are formed between the multiple teeth of the rotor tooth portion 21. The suction-side shaft portion 22, for example, penetrates the casing 4 and is configured to share a shaft portion with the drive source 70. A shaft seal member 8 is disposed on the suction-side shaft portion 22 of the male rotor 2. The shaft seal member 8 is, for example, an oil seal or a mechanical seal.

[0016] As shown in Figure 2, the female rotor 3 is composed of a rotor tooth portion 31 having a plurality of twisted teeth (lobes) 31a, and a suction-side shaft portion (not shown) and a discharge-side shaft portion 33 provided on both axial ends of the rotor tooth portion 31. Similar to the rotor tooth portion 21 of the male rotor 2, the rotor tooth portion 31 has a suction-side end face and a discharge-side end face (not shown) at one axial end and the other axial end, respectively. Tooth spaces are formed between the plurality of teeth 31a of the rotor tooth portion 31.

[0017] 1, the casing 4 includes a main casing 41 and a discharge-side casing 42 attached to the discharge side of the main casing 41. A suction-side cover 43 is attached to the suction side of the main casing 41. A discharge-side cover 44 is attached to the discharge-side casing 42 on the side opposite to the side to which the main casing 41 is attached.

[0018] As shown in Figures 1 and 2, a storage chamber 45 is formed inside the casing 4 to store the rotor teeth 21 of the male rotor 2 and the rotor teeth 31 of the female rotor 3 in a state where they are meshed with each other. The storage chamber 45 is formed by closing off the opening on one axial side (the upper side in Figure 1) of two partially overlapping cylindrical spaces, or bores, formed in the main casing 41 with the discharge-side casing 42. The storage chamber 45 consists of a male-side bore 45a in which the rotor teeth 21 of the male rotor 2 are arranged, and a female-side bore 45b in which the rotor teeth 31 of the female rotor 3 are arranged. The wall surfaces that form the storage chamber 45 are composed of a wall surface of a male-side bore 45a that covers the radial outside of the rotor tooth portion 21 of the male rotor 2, a wall surface of a female-side bore 45b that covers the radial outside of the rotor tooth portion 31 of the female rotor 3, a suction-side inner wall surface 48 on one axial side (lower side in FIG. 1) that faces the suction-side end faces 21b of the rotor tooth portions 21, 31 of both the male and female rotors 2, 3, and a discharge-side inner wall surface 49 on the other axial side (upper side in FIG. 1) that faces the discharge-side end faces 21c of the rotor tooth portions 21, 31 of both the male and female rotors 2, 3. As shown in FIG. 2, the wall surfaces of the storage chamber 45 have two intersection lines between the wall surface of the male-side bore 45a and the wall surface of the female-side bore 45b. The intersection line located on the relatively low-pressure side is called the suction-side cusp 50, and the intersection line located on the relatively high-pressure side is called the compression-side cusp 51.

[0019] The rotor teeth 21, 31 of the male and female rotors 2, 3 are arranged with gaps of several tens to several hundreds of μm relative to the inner wall surfaces of the casing 4 (the wall surfaces of the male bore 45a, the wall surfaces of the female bore 45b, the suction-side inner wall surface 48, and the discharge-side inner wall surface 49). A plurality of working chambers C are formed by the rotor teeth 21, 31 of the male and female rotors 2, 3 and the inner wall surface of the casing 4 that surrounds them. As the male and female rotors 2, 3 rotate, the working chambers C expand and contract while moving axially, and working gas is sucked into the working chambers C and compressed.

[0020] A suction side bearing 6 for the male rotor 2 and the female rotor 3 is disposed at the suction side end of the main casing 41. A discharge side bearing 7 for the male rotor 2 and the female rotor 3 is disposed in the discharge side casing 42.

[0021] 1, the casing 4 is provided with an intake passage 53 that guides gas from the outside of the casing 4 to the working chamber C. The casing 4 is also provided with a discharge passage 54 that guides compressed gas from the working chamber C to the outside of the casing 4. The discharge passage 54 connects the working chamber C in the discharge stroke with the outside of the casing 4, and has a discharge port 54a that opens to the storage chamber 45.

[0022] The casing 4 is provided with a first fluid supply passage 56 for supplying lubricating liquid to the suction-side bearings 6 and shaft seal members 8 for the male rotor 2 and female rotor 3, and a second fluid supply passage 57 for supplying lubricating liquid to the discharge-side bearings 7 for the male rotor 2 and female rotor 3. The casing 4 is also provided with a third fluid supply passage 58 for introducing liquid into the working chamber C (storage chamber 45). The third fluid supply passage 58 opens, for example, to the compression-side cusp 51 side of the storage chamber 45. In other words, the third fluid supply passage 58 opens to the region where the working chamber C undergoes the compression stroke.

[0023] A liquid supply system 80 is connected to the third liquid supply passage 58 of the casing 4. The liquid supply system 80 includes, for example, a gas-liquid separator 81, a liquid cooler 82, an auxiliary device 83, and a conduit 84 connecting them. The gas-liquid separator 81 is connected to the discharge passage 54 of the casing 4 via the conduit 84 and separates and recovers liquid contained in the compressed gas discharged from the compressor main body 1. The liquid cooler 82 cools the liquid separated from the compressed gas by the gas-liquid separator 81 and is, for example, an air-cooled or water-cooled heat exchanger. The auxiliary device 83 includes a filter that filters out impurities contained in the liquid supplied to the compressor main body 1 and a check valve that prevents the liquid from flowing back. The liquid supply system 80 of this embodiment further includes a viscometer 85 that detects the viscosity of the liquid supplied to the compressor main body 1. The viscometer 85 outputs a detection signal corresponding to the detected viscosity to a control device 90 (described later). The liquid supply system 80 of this embodiment is configured to supply liquid to the compressor body 1 using the pressure of the compressed gas flowing into the gas-liquid separator 81 as a driving source, without using a power source such as a pump.

[0024] The third liquid supply passage 58 of the casing 4 is provided with a liquid supply mechanism 60 that injects liquid supplied from a liquid supply system 80 into the working chamber C (inside the storage chamber 45). The liquid supply mechanism 60 of this embodiment generates a swirling flow in the liquid flowing through the third liquid supply passage 58 and injects the swirling flow of liquid into the working chamber C (inside the storage chamber 45). In this liquid supply mechanism 60, as shown in FIG. 2, the centrifugal force generated by the swirling flow causes the liquid to break down into fine droplets and spread within the working chamber C (see the dotted line area L). The configuration and structure of the liquid supply mechanism 60 will be described in detail below.

[0025] The control device 90 controls the overall operation of the compressor main body 1. The control device 90 of this embodiment is communicatively or electrically connected to the viscometer 85 and is configured to receive a detection signal (detection value) from the viscometer 85. The control device 90 is configured to adjust the swirl amount (swirl strength) of the swirl flow generated by the liquid supply mechanism 60 based on the detection value from the viscometer 85. The control device 90 includes a storage device 91 including, for example, RAM, ROM, etc., and a processing device 92 including a CPU, MPU, etc. The storage device 91 pre-stores programs and various information required to adjust the swirl amount (swirl strength) of the swirl flow generated by the liquid supply mechanism 60. The processing device 92 appropriately reads the programs and various information from the storage device 91 and executes processing in accordance with the programs to realize various functions. Details of the control method of the control device 90 will be described later.

[0026] Next, the structure of the liquid supply mechanism in the screw compressor according to the first embodiment will be described with reference to Figures 2 to 5. Figure 3 is a cross-sectional view showing an enlarged state of the liquid supply mechanism of the screw compressor according to the first embodiment. Figure 4 is a cross-sectional view of a swirl flow generator, which is part of the liquid supply mechanism of the screw compressor according to the first embodiment shown in Figure 3, as seen from the direction of arrows IV-IV. Figure 5 is a cross-sectional view of a swirl adjustment member, which is part of the liquid supply mechanism of the screw compressor according to the first embodiment shown in Figure 3, as seen from the direction of arrows VV.

[0027] 2 and 3, the third liquid supply passage 58 of the casing 4 is, for example, a circular hole. A liquid supply mechanism 60 is provided in the third liquid supply passage 58. As shown in FIG. 2, the liquid supply mechanism 60 can be configured as a structure separate from the casing 4 and detachably attached to the third liquid supply passage 58. Alternatively, as shown in FIG. 3, the liquid supply mechanism 60 can be configured as a structure formed directly on the casing 4. As shown in FIG. 3, the liquid supply mechanism 60 includes: an injection hole 61 that opens to the storage chamber 45 in the casing 4 via a buffer space 64; a swirl flow generator 62 located upstream of the injection hole 61 and that swirls the liquid supplied from the liquid supply system 80 to generate a swirl flow; and a swirl adjustment device 63 located upstream of the swirl flow generator 62 and that adjusts the amount of swirl or the strength of the swirl of the swirl flow generated by the swirl flow generator 62.

[0028] The injection hole 61 is configured, for example, as a thin round hole having a hole diameter smaller than that of the third liquid supply passage 58. The injection hole 61 is configured so that an opening (outlet) 61a on one side opens to the buffer space 64 and an opening (inlet) 61b on the other side opens to the center of the swirl flow generator 62.

[0029] As shown in FIGS. 3 and 4 , the swirl flow generator 62 is configured as a disk-shaped member having a swirl chamber 621 connected to the injection hole 61 and an introduction path 622 connected to the swirl chamber 621. The swirl chamber 621 is formed as a space shaped like a cylinder with a diameter larger than that of the injection hole 61. The injection hole 61 opens near the center of the swirl chamber 621. The introduction path 622 is configured to introduce liquid in a tangential direction of the swirl chamber 621. That is, the introduction path 622 is connected to the outer periphery of the swirl chamber 621 so as to be offset from the center of the swirl chamber 621, and is, for example, a linear flow path perpendicular to the axial direction of the swirl chamber 621. The swirl flow generator 62 has, for example, two introduction paths 622. The two introduction paths 622 are arranged, for example, substantially point-symmetrically with respect to the center position of the swirl chamber 621. The swirl flow generator 62 may have one or three or more introduction paths 622 depending on constraints such as the size of the swirl chamber 621 and the introduction path 622.

[0030] 3 and 5, the swirl adjustment device 63 includes a rotatable swirl adjustment member 66 arranged upstream of the swirl flow generator 62, and a drive device 67 such as a motor that rotates the swirl adjustment member 66. The drive device 67 is, for example, a motor, and is configured to rotate the swirl adjustment member 66 in response to a command from the control device 90 (see FIG. 1).

[0031] The swirl adjustment member 66 is disposed in the axial direction of the swirl chamber 621 relative to the swirl flow generator 62, and is, for example, a disk-shaped member configured as part of the wall surface of the swirl chamber 621 of the swirl flow generator 62. The swirl adjustment member 66 has a notch 68 as an opening that opens into the introduction passage 622 of the swirl flow generator 62. The swirl adjustment member 66 is connected to a drive unit 67 via a rotation shaft 69, and the rotation angle is adjusted by the drive unit 67. The swirl adjustment member 66 is configured so that the opening state of the opening 68 relative to the introduction passage 622 of the swirl flow generator 62 changes in accordance with changes in the rotation angle. The opening state of the opening 68 indicates the opening area and opening position relative to the introduction passage 622. When the opening state of the openings (notches) 68 of the swirl flow generator 62 relative to the introduction passage 622 changes, the flow rate of the liquid flowing into the introduction passage 622 and the velocity distribution within the introduction passage 622 change, thereby changing the amount of swirl (swirl strength) of the swirl flow generated in the swirl chamber 621. In other words, the openings 68 of the rotating swirl adjustment member 66 function as an adjustment unit that adjusts the flow of liquid supplied from the third liquid supply passage 58 to the introduction passage 622 of the swirl flow generator 62. The number of notches (openings) 68 of the swirl adjustment member 66 corresponds to the number of introduction passages 622 of the swirl flow generator 62, and is, for example, two. The two notches (openings) 68 are arranged, for example, substantially point-symmetrically with respect to the rotation axis 69 of the swirl adjustment member 66.

[0032] In the liquid supply mechanism 60 configured as described above, the liquid flowing through the third liquid supply passage 58 flows into the inlet passage 622 of the swirl flow generator 62 through the opening (notch) 68 of the swirl adjustment member 66. In the swirl flow generator 62, a swirl flow is generated when the liquid flows from the inlet passage 622 into the swirl chamber 621, and the swirl flow of the liquid passes through the injection hole 61 and is injected into the buffer space 64. The liquid injected from the injection hole outlet 61a first forms an umbrella-shaped liquid film F, the tip of which breaks into a liquid filament L. The liquid filament L then breaks into multiple droplets P, generating fine droplets. The buffer space 64 is provided to prevent the liquid injected from the injection hole 61 from contacting the male rotor 2 or female rotor 3 in the form of the liquid film F or liquid filament L, and to allow the liquid to diffuse into the working chamber C (storage chamber 45) in the form of multiple droplets P.

[0033] In order to reduce the diameter of the liquid droplets generated by the injection of the liquid supply mechanism 60, it is necessary to increase the swirl amount or strength of the swirl flow generated by the swirl flow generator 62, thereby increasing the centrifugal force and thereby reducing the thickness of the liquid film F. The cooling effect on the compressed gas is improved by atomization of the liquid, which improves the compression efficiency of the screw compressor. However, when the liquid is oil, the increase in the total surface area due to atomization of the liquid accelerates oil degradation due to oxidation. If oil degradation occurs too quickly, the interval between maintenance such as oil changes will be shortened. To extend the interval between oil maintenance, the diameter of the liquid droplets must be increased.

[0034] The liquid supply mechanism 60 of this embodiment is capable of adjusting the amount of swirl or strength of swirl of the swirling flow generated by the swirling flow generator 62 by changing the opening state of the opening (notch) 68 relative to the inlet passage 622 of the swirling flow generator 62 according to the rotation angle of the rotatable swirl adjustment member 66.

[0035] Next, a liquid supply mechanism of a screw compressor according to a first modified example of the first embodiment will be described with reference to Figures 6 to 9. Figure 6 is a cross-sectional view showing a rotation adjustment member of the screw compressor according to the first modified example of the first embodiment.

[0036] The first modified example shown in FIG. 6 differs from the first embodiment in that the shape of a notch 68A (opening) of a swirl adjustment member 66A in a liquid supply mechanism 60 is different. The swirl adjustment member 66A of the first modified example is configured so that the opening area of ​​the opening 68A relative to the introduction passage 622 of the swirl flow generator 62 changes monotonically as the rotation angle increases. That is, the swirl adjustment member 66A of the first modified example changes the flow rate of liquid flowing into the introduction passage 622 of the swirl flow generator 62 in accordance with changes in the rotation angle. The swirl adjustment member 66A of the first modified example is further configured so that the opening of the opening (notch) 68A relative to a region of the introduction passage 622 of the swirl flow generator 62 that is connected to the outer periphery of the swirl chamber 621 (hereinafter, sometimes referred to as the outer periphery 622a of the introduction passage 622) is maintained when the rotation angle is such that the opening area of ​​the opening 68A becomes relatively small.

[0037] Specifically, notch (opening) 68A of swirl adjustment member 66A is formed along the outer peripheral edge of the disk-shaped member, has a beak shape tapering from one end 681 to the other end 682 in the circumferential direction, and is configured to open into introduction passage 622 of swirl flow generator 62. Furthermore, swirl adjustment member 66A is configured so that the direction of notch (opening) 68A from one end 681 to the other end 682 coincides with the direction from a region of introduction passage 622 connected to the inner peripheral side of swirl chamber 621 (hereinafter sometimes referred to as inner peripheral side 622b of introduction passage 622) to a region connected to the outer peripheral side of swirl chamber 621 (outer peripheral side 622a of introduction passage 622).

[0038] Here, the function of the swirl adjustment member of the first modified example will be described with reference to Figures 7 to 9. Figure 7 is a characteristics diagram showing an example of the relationship between the rotation angle of the swirl adjustment member of the first modified example shown in Figure 6 and the opening area relative to the swirl flow generator. Figure 8 is a diagram showing the opening state relative to the swirl flow generator when the swirl adjustment member of the first modified example shown in Figure 6 is at a certain rotation angle. Figure 9 is a diagram showing the opening state relative to the swirl flow generator when the swirl adjustment member of the first modified example shown in Figure 6 is at a rotation angle different from that shown in Figure 7.

[0039] A swirl adjustment member 66A of a first modified example shown in FIG. 6 has a beak-shaped opening 68A tapered from one end 681 to the other end 682 in the circumferential direction on the outer peripheral edge of a disk-shaped member. As a result, as shown in FIG. 7, the opening area of ​​the opening 68A relative to the inlet passage 622 of the swirl flow generator 62 changes monotonically as the rotation angle of the swirl adjustment member 66A increases. In FIG. 7, the horizontal axis θ represents the rotation angle of the swirl adjustment member 66A, and the vertical axis A represents the opening area of ​​the opening 68A relative to the inlet passage 622 of the swirl flow generator 62. For example, when the rotation angle θ increases, as shown in FIG. 9, the swirl adjustment member 66A exhibits a first characteristic diagram (solid line) in which the opening area A of the opening 68A monotonically decreases. On the other hand, when the rotation angle increases, as shown in FIG. 9, the opening area A of the opening 68A monotonically increases, as shown in FIG. 2 (dashed line). 8 and 9, the hatched area indicates the opening area of ​​the opening 68A of the swirl adjustment member 66A relative to the introduction passage 622 of the swirl flow generator 62.

[0040] 8, the opening area (hatched portion) of opening 68A relative to introduction path 622 of swirl flow generator 62 is relatively larger than when swirl adjustment member 66A is rotated at the angle shown in Fig. 9, and the opening region (hatched portion) of opening 68A is secured from inner circumferential side 622b to outer circumferential side 622a of introduction path 622. This relatively increases the flow rate of liquid flowing into introduction path 622 of swirl flow generator 62 via opening 68A of swirl adjustment member 66A, and secures a flow with a flow velocity equal to or greater than a predetermined value in the region of outer circumferential side 622a of introduction path 622. As a result, the amount of swirl (strength of swirl) of the swirl flow generated by swirl flow generator 62 increases.

[0041] On the other hand, when the swirl adjustment member 66A is rotated at the angle shown in FIG. 9, the opening area (shaded portion) of the opening 68A of the swirl flow generator 62 relative to the introduction path 622 is relatively smaller than when the swirl adjustment member 66A is rotated at the angle shown in FIG. 8. However, the opening area (shaded portion) of the opening 68A is secured from the inner peripheral region 622b of the introduction path 622 to the outer peripheral region 622a. This relatively reduces the flow rate of the liquid flowing into the introduction path 622 of the swirl flow generator 62 through the opening 68A of the swirl adjustment member 66A. However, a flow with a flow velocity equal to or greater than a predetermined value is secured in the region of the outer peripheral side 622a of the introduction path 622. As a result, the generation of a swirl flow by the swirl flow generator 62 is maintained, while the amount of swirl of the swirl flow (the strength of the swirl) is reduced.

[0042] As described above, in the swirl adjustment member 66A of the first modified example, the opening area of ​​the opening 68A relative to the introduction passage 622 of the swirl flow generator 62 changes monotonically in accordance with changes in the rotation angle, and the opening area (the shaded area in FIGS. 8 and 9) of the opening 68A is secured from the inner circumferential side 622b to the outer circumferential side 622a of the introduction passage 622. As a result, while maintaining the generation of a swirl flow by the swirl flow generator 62, the flow rate of the liquid flowing into the introduction passage 622 of the swirl flow generator 62 can be increased or decreased, thereby changing the amount of swirl (swirl strength) of the swirl flow generated by the swirl flow generator 62.

[0043] Next, a liquid supply mechanism of a screw compressor according to a second modified example of the first embodiment will be described with reference to Figures 10 to 13. Figure 10 is a cross-sectional view showing a rotation adjustment member of the screw compressor according to the second modified example of the first embodiment.

[0044] The second modified example shown in FIG. 10 differs from the first embodiment in that the shape of a notch 68B (opening) of a swirl adjustment member 66B in a liquid supply mechanism 60 is different. The swirl adjustment member 66B of the second modified example is configured so that the opening area of ​​the opening 68B relative to the introduction passage 622 of the swirl flow generator 62 falls within a predetermined range with changes in the rotation angle, and the opening position of the opening 68B relative to the introduction passage 622 of the swirl flow generator 62 moves in response to changes in the rotation angle. In other words, the swirl adjustment member 66B of the second modified example is configured to minimize changes in the flow rate of liquid flowing into the introduction passage 622 of the swirl flow generator 62 with changes in the rotation angle. The swirl adjustment member 66B is further configured to change the velocity distribution of the liquid from the inner circumferential side 622b to the outer circumferential side 622a of the introduction passage 622 in response to changes in the rotation angle.

[0045] Specifically, notch (opening) 68B of swirl adjustment member 66B is formed in the outer circumferential edge portion of the disk-shaped member and has a fan shape, and is configured to open into introduction passage 622 of swirl flow generator 62. At a certain rotational position (see FIG. 12 ), swirl adjustment member 66B is configured so that one side 683 of the fan shape of opening (notch) 68B overlaps with the position of the wall surface of inner circumferential side 622b of introduction passage 622, and the other side 684 of the fan shape of opening (notch) 68B crosses introduction passage 622. In other words, swirl adjustment member 66B is configured so that even when the rotation angle changes, the opening of opening (notch) 68B relative to inner circumferential side 622b of introduction passage 622 is maintained, while the opening area of ​​opening (notch) 68B relative to inner circumferential side 622b of introduction passage 622 moves.

[0046] Here, the function of the swirl adjustment member of the second modified example will be described with reference to Figures 11 to 13. Figure 11 is a characteristic diagram showing an example of the relationship between the rotation angle of the swirl adjustment member of the second modified example shown in Figure 10 and the opening area relative to the swirl flow generator. Figure 12 is a diagram showing the opening state relative to the swirl flow generator when the swirl adjustment member of the second modified example shown in Figure 10 is at a certain rotation angle. Figure 13 is a diagram showing the opening state relative to the swirl flow generator when the swirl adjustment member of the second modified example shown in Figure 10 is at a rotation angle different from that shown in Figure 12.

[0047] In a second modified example of a swirl adjustment member 66B shown in FIG. 12, one side 683 of a sector-shaped opening (cutout) 68B overlaps with the wall surface of the inner circumferential side 622b of the introduction passage 622, and the other side 684 of the sector-shaped opening (cutout) 68B crosses the introduction passage 622 at a certain rotational position. As a result, as shown in FIG. 11, the opening area of ​​the opening 68B relative to the introduction passage 622 of the swirl flow generator 62 remains substantially constant within a predetermined range with respect to changes in the rotation angle of the swirl adjustment member 66B. In FIG. 11, the horizontal axis θ represents the rotation angle of the swirl adjustment member 66B, and the vertical axis A represents the opening area of ​​the opening 68B relative to the introduction passage 622 of the swirl flow generator 62. When the swirl adjustment member 66B is changed, for example, from FIG. 12 to FIG. 13, the opening area A of the opening 68B only increases or decreases slightly. 12 and 13, the hatched area indicates the opening area of ​​the opening 68B of the swirl adjustment member 66B relative to the introduction passage 622 of the swirl flow generator 62.

[0048] 12, one side 683 of fan-shaped notch 68B substantially overlaps the position of the wall surface of inner circumferential side 622b of introduction path 622, ensuring a large opening area (hatched portion) of opening 68B from inner circumferential side 622b to outer circumferential side 622a of introduction path 622. This ensures a considerable flow rate of liquid flowing into introduction path 622 via opening 68B of rotation adjustment member 66B, and also ensures a flow from inner circumferential side 622b to outer circumferential side 622a of introduction path 622.

[0049] 13, the opening area (hatched portion) of opening 68B relative to introduction path 622 is maintained substantially the same compared to the case of the rotation angle shown in FIG. 12. As a result, the flow rate of liquid flowing into introduction path 622 is maintained substantially the same regardless of changes in the rotation angle of rotation adjustment member 66B. Furthermore, opening 68B of rotation adjustment member 66B has an opening area (hatched portion) on outer circumferential side 622a of introduction path 622, but does not have an opening area near the wall surface of inner circumferential side 622b of introduction path 622. As a result, compared to the case of the rotation angle shown in FIG. 12, the flow rate of liquid in the area on inner circumferential side 622b of introduction path 622 decreases, while the flow rate of liquid in the area on outer circumferential side 622a of introduction path 622 is maintained. That is, the velocity distribution of the liquid from the inner circumferential side 622b to the outer circumferential side 622a of the introduction path 622 changes compared to the case of the rotation angle shown in Fig. 12. The velocity difference between the outer circumferential side 622a and the inner circumferential side 622b of the introduction path 622 becomes relatively large. As a result, the swirl amount or strength of the swirl flow generated by the swirl flow generator 62 changes.

[0050] In this way, in the swirl adjustment member 66B of the second modified example, the opening area of ​​the opening 68B relative to the introduction passage 622 of the swirl flow generator 62 is maintained substantially constant regardless of the change in the rotation angle. 622 While the opening area (hatched area) of opening 68B relative to outer circumferential side 622a of introduction path 622 is maintained, the opening area of ​​opening 68B relative to inner circumferential side 622b of introduction path 622 moves in accordance with the change in the rotation angle. As a result, the flow rate of the liquid flowing into introduction path 622 of swirl flow generator 62 is maintained approximately constant, and by changing the velocity distribution of the liquid in introduction path 622 from inner circumferential side 622b to outer circumferential side 622a, the swirl amount (swirl strength) of the swirl flow generated by swirl flow generator 62 can be changed.

[0051] Next, a control method (liquid supply method) for the screw compressor according to the first embodiment and the first to second modifications will be described with reference to Fig. 1 and Fig. 14 to Fig. 16. Fig. 14 to Fig. 16 are characteristic diagrams used for controlling the rotation adjustment device in the screw compressor according to the first embodiment and the first to second modifications.

[0052] The control device 90 of the screw compressor 100 shown in Fig. 1 is configured to use the detection value (viscosity of the liquid) of the viscometer 85 to control the rotation angles of the swirl adjustment members 66, 66A, 66B (see Figs. 3, 5, 6, and 10) of the swirl adjustment device 63 in the liquid supply mechanism 60 of the compressor body 1, thereby adjusting the amount of swirl of the swirl flow generated by the swirl flow generator 62 (see Figs. 3 and 4) of the liquid supply mechanism 60. The control device 90 controls the rotation angles of the swirl adjustment members 66, 66A, 66B by using, for example, the characteristic diagrams shown in Figs. 14 to 16.

[0053] The characteristic diagrams shown in FIGS. 14 to 16 are stored in advance in the storage device 91 (see FIG. 1) of the control device 90. FIG. 14 is a characteristic diagram showing the relationship between the viscosity of the liquid supplied to the liquid supply mechanism 60 and the droplet diameter of the liquid generated by the liquid supply mechanism 60's jet. In FIG. 14, the horizontal axis v represents the liquid viscosity, and the vertical axis D represents the droplet diameter. FIG. 15 is a characteristic diagram showing the relationship between the droplet diameter of the liquid generated by the liquid supply mechanism 60's jet and the swirl amount (swirl strength) of the swirl flow generated by the swirl flow generator 62 of the liquid supply mechanism 60. In FIG. 15, the horizontal axis S represents the swirl amount of the swirl flow, and the vertical axis D represents the droplet diameter. FIG. 16 is a characteristic diagram showing the relationship between the swirl amount (swirl strength) of the swirl flow generated by the swirl flow generator 62 and the rotation angle of the swirl adjustment members 66, 66A, and 66B. In FIG. 16, the horizontal axis S indicates the amount of swirl of the swirl flow, and the vertical axis θ indicates the rotation angle of the swirl adjustment members 66, 66A, 66B.

[0054] Specifically, the control device 90 first sets a target viscosity of the liquid to be supplied to the liquid supply mechanism 60 based on the value detected by the viscometer 85. The target viscosity is set taking into consideration, for example, the elapsed time of use of the liquid and the replacement time. When oil is used as the liquid, the longer the elapsed time of use, the more the oil deteriorates and the lower its viscosity becomes.

[0055] Next, the control device 90 estimates the droplet diameter of the liquid generated by the liquid supply mechanism 60 by referring to the characteristic diagram shown in FIG. 14 using the set target viscosity (see the arrow from (1) to (2) in FIG. 14). Next, the control device 90 calculates the swirl amount of the swirl flow to be generated by the swirl flow generator 62 by referring to the characteristic diagram shown in FIG. 15 using the calculated droplet diameter (see the arrow from (2) to (3) in FIG. 15). Finally, the control device 90 calculates the rotation angle of the swirl adjustment members 66, 66A, and 66B to generate the calculated swirl amount of the swirl flow by referring to the characteristic diagram shown in FIG. 16 (see the arrow from (3) to (4) in FIG. 16). The control device 90 outputs a command to the drive device 67 of the swirl adjustment device 63 (see FIG. 3) to set the rotation angle of the swirl adjustment members 66, 66A, and 66B obtained as a result of the calculation as the target rotation angle.

[0056] The control device 90 periodically receives the detection signal (viscosity of the liquid) from the viscometer 85 and sequentially performs the above-mentioned calculations to constantly control the rotation angles of the rotation adjustment members 66, 66A, 66B. This adjusts the diameter of the droplets generated by the liquid being sprayed from the liquid supply mechanism 60 into the working chamber C (storage chamber 45), thereby achieving a balance between the cooling effect of the compressed gas in the working chamber C (compression efficiency) and the degree of deterioration of the atomized liquid (maintenance efficiency).

[0057] As described above, the screw compressor 100 according to the first embodiment and its modifications includes the compressor body 1 including the male rotor 2 and the female rotor 3 (screw rotors), the storage chamber 45 that rotatably stores the male rotor 2 and the female rotor 3 (screw rotors), and the casing 4 having the liquid supply mechanism 60 that injects liquid into the storage chamber 45, and the liquid supply system 80 that recovers liquid contained in the compressed gas discharged from the compressor body 1 and supplies it to the liquid supply mechanism 60 in the casing 4. The liquid supply mechanism 60 includes an injection hole 61 that opens into the storage chamber 45 and a swirl flow generator 62 that is located upstream of the injection hole 61 and swirls the liquid supplied from the liquid supply system 80 to generate a swirl flow. The liquid supply mechanism 60 also includes a swirl adjustment device 63 that adjusts the amount of swirl of the swirl flow generated by the swirl flow generator 62.

[0058] According to this configuration, by adjusting the amount of swirl of the swirl flow generated by the swirl flow generator 62 with the swirl adjustment device 63, it becomes possible to adjust the droplet size of the liquid generated by the injection of the liquid supply mechanism 60. Therefore, it becomes possible to operate the screw compressor 100 in consideration of both the compression efficiency and maintenance efficiency when turning the liquid to be supplied to the working chamber C in the compressor main body 1 into fine droplets.

[0059] Furthermore, the liquid supply mechanism 60 according to this embodiment includes a swirl adjustment device 63 that is disposed upstream of the swirl flow generator 62 and includes rotatable swirl adjustment members 66, 66A, 66B having openings 68, 68A, 68B that open into the flow path of the swirl flow generator 62. The swirl adjustment members 66, 66A, 66B are configured so that the opening states of the openings 68, 68A, 68B relative to the flow path of the swirl flow generator 62 change in accordance with changes in the rotation angle.

[0060] According to this configuration, by changing the rotation angle of the swirl adjustment members 66, 66A, 66B, it is possible to adjust the flow rate or velocity distribution of the liquid introduced into the swirl flow generator 62 through the openings 68, 68A, 68B of the swirl adjustment members 66, 66A, 66B. By adjusting this flow rate or velocity distribution, it is possible to adjust the amount of swirl of the swirl flow generated by the swirl flow generator 62, so that it is possible to operate the screw compressor 100 in consideration of both the compression efficiency and maintenance efficiency when breaking down the liquid into fine droplets to be supplied to the working chamber C in the compressor body 1.

[0061] Furthermore, the swirl adjustment member 66A according to the first modified example of this embodiment is configured so that the opening area of ​​the opening 68A relative to the introduction path 622 (flow path) of the swirl flow generator 62 changes monotonically as the rotation angle increases.

[0062] According to this configuration, by changing the rotation angle of the swirl adjustment member 66A, it is possible to adjust the flow rate of the liquid introduced into the swirl flow generator 62 through the opening 68A of the swirl adjustment member 66A. By adjusting this flow rate, it is possible to adjust the amount of swirl of the swirl flow generated by the swirl flow generator 62, so that operation can take into consideration both the compression efficiency and maintenance efficiency of the screw compressor 100 when breaking down the liquid into fine droplets to be supplied to the working chamber C in the compressor body 1.

[0063] In a first modified example of this embodiment, swirl flow generator 62 has a swirl chamber 621 connected to injection hole 61 to generate a swirl flow, and an introduction passage 622 connected to swirl chamber 621 to introduce liquid tangentially to swirl chamber 621. Swirl adjustment member 66A is a disk-shaped member arranged in the axial direction of swirl chamber 621 relative to swirl flow generator 62, and opening 68A of swirl adjustment member 66A is formed on the outer peripheral edge of the disk-shaped member and has a shape that tapers from one end 681 to the other end 682 in the circumferential direction, and is configured to open into introduction passage 622 of swirl flow generator 62. Furthermore, swirl adjustment member 66A is configured such that the direction of opening 68A from one end 681 to the other end 682 coincides with the direction from inner peripheral side 622b to outer peripheral side 622a of introduction passage 622.

[0064] This configuration makes it possible to adjust the flow rate of the liquid introduced into the swirl flow generator 62, and also ensures a flow rate that flows into the outer circumferential side 622a of the introduction path 622 even if the flow rate introduced into the swirl flow generator 62 decreases. This makes it possible for the swirl flow generator 62 to generate a swirl flow even when the flow rate introduced into the swirl flow generator 62 is low.

[0065] Furthermore, the swirl adjustment member 66B according to the second modified example of this embodiment is configured so that the opening area of ​​the opening 68B relative to the inlet passage 622 (flow path) of the swirl flow generator 62 falls within a predetermined range with changes in the rotation angle, and the opening position of the opening 68B relative to the inlet passage 622 (flow path) of the swirl flow generator 62 moves in accordance with changes in the rotation angle.

[0066] According to this configuration, the amount of swirl of the swirling flow generated by the swirling flow generator 62 can be adjusted by changing the velocity distribution in the introduction path 622 while maintaining a substantially constant flow rate of the liquid introduced into the swirling flow generator 62. In other words, it is possible to adjust the size of the droplet diameter of the liquid to take into account the compression efficiency and maintenance efficiency of the screw compressor 100 while maintaining a substantially constant flow rate of the liquid supplied to the working chamber C.

[0067] Furthermore, in a second modified example of this embodiment, opening 68B of swirl adjustment member 66B is formed in a fan shape on the outer periphery of the disk-shaped member and is configured to open into introduction path 622 of swirl flow generator 62. Furthermore, swirl adjustment member 66B is configured such that, at a certain rotational position, one side 683 of the fan shape of opening 68B overlaps with the position of the wall surface on inner periphery 622b of introduction path 622, and the other side 684 of the fan shape of opening 68B crosses introduction path 622.

[0068] According to this configuration, the swirl adjustment member 66B can be realized with a simple structure, which is capable of changing the velocity distribution in the introduction path 622 while maintaining the flow rate of the liquid introduced into the swirl flow generator 62 substantially constant.

[0069] Furthermore, in this embodiment, the liquid supply mechanism 60 is a separate structure from the casing 4 and is configured to be detachable from the casing 4. This configuration makes it easier to manufacture the liquid supply mechanism 60 than when the liquid supply mechanism 60 is formed directly on the casing 4.

[0070] The screw compressor 100 according to this embodiment also includes a viscometer 85 that detects the viscosity of the liquid supplied to the liquid supply mechanism 60, and a control device 90 that controls the swirl adjustment device 63. The control device 90 is configured to adjust the amount of swirl of the swirl flow generated by the swirl flow generator 62 by controlling the swirl adjustment device 63 based on the detection value of the viscometer 85.

[0071] According to this configuration, the amount of swirl of the swirl flow is adjusted using viscosity, which is an index of deterioration of the liquid, so that operation of the screw compressor 100 can take into consideration both the compression efficiency and maintenance efficiency.

[0072] Furthermore, in this embodiment, the control device 90 is configured to perform control using a characteristics diagram that shows the relationship between the viscosity and droplet diameter of the liquid generated by the spray from the liquid supply mechanism 60. With this configuration, the control device 90 can adjust the amount of swirl of the swirling flow based on the viscosity, which is an index of liquid deterioration, from the relationship in this characteristics diagram.

[0073] As described above, the liquid supply method for the screw compressor of this embodiment includes a viscosity detection step of detecting the viscosity of the liquid supplied to the liquid supply mechanism 60, and a swirl adjustment step of adjusting the amount of swirl of the swirl flow generated by the swirl flow generator 62 based on the viscosity of the liquid detected in the viscosity detection step.

[0074] According to this configuration, the amount of swirl of the swirl flow is adjusted using viscosity, which is an index of deterioration of the liquid, so that operation of the screw compressor 100 can take into consideration both the compression efficiency and maintenance efficiency.

[0075] [Second embodiment] Next, a screw compressor according to a second embodiment will be described with reference to Figures 17 and 18. In Figures 17 and 18, the same reference numerals as those shown in Figures 1 to 16 denote similar parts, and detailed description thereof will be omitted. Figure 17 is a diagram showing the configuration of a screw compressor according to a second embodiment of the present invention.

[0076] The screw compressor 100C according to the second embodiment shown in Fig. 17 differs from the first embodiment in that the liquid supply mechanism 60C of the compressor body 1 does not have the function of a swing adjustment device, and instead the liquid supply system 80C has a pump 87 or a control valve 88 as a swing adjustment device. Furthermore, the control method of the control device 90C for the swing adjustment device differs depending on the change in the swing adjustment device.

[0077] Specifically, the liquid supply mechanism 60C of the compressor body 1 is configured such that the drive device 67 of the swirl adjustment device 63 of the liquid supply mechanism 60 (see FIG. 3) of the first embodiment is omitted, and the swirl adjustment member 66 is fixed so as not to be able to rotate relative to the swirl flow generator 62. In other words, the non-rotatable swirl adjustment member 66 is configured so that the opening state of the opening 68 relative to the introduction passage 622 of the swirl flow generator 62 does not change, and does not function as a swirl adjustment device that adjusts the amount of swirl of the swirl flow generated by the swirl flow generator 62.

[0078] On the other hand, the liquid supply system 80C includes a pump 87 and a control valve 88 in addition to the components of the liquid supply system 80 of the first embodiment, such as the gas-liquid separator 81, the liquid cooler 82, the auxiliary equipment 83, the pipeline 84, and the viscometer 85. The pump 87 is disposed, for example, downstream of the gas-liquid separator 81 and upstream of the liquid cooler 82. The pump 87 is configured to adjust the pressure of the liquid supplied to the liquid supply mechanism 60C of the compressor main body 1 by changing the discharge pressure. The pump 87 is configured to change the discharge pressure in response to a command from the control device 90C. The control valve 88 is disposed, for example, downstream of the viscometer 85. The control valve 88 is configured to adjust the pressure of the liquid supplied to the liquid supply mechanism 60C of the compressor main body 1 by changing the valve opening. The control valve 88 is configured to change the valve opening in response to a command from the control device 90C.

[0079] In the swirl flow generator 62 of the liquid supply mechanism 60C of the compressor main body 1, the amount of swirl of the generated swirl flow changes depending on the pressure of the supplied liquid. In other words, the pump 87 and control valve 88 of the liquid supply system 80C function as a swirl adjustment device that adjusts the amount of swirl (swirl strength) of the swirl flow generated in the swirl flow generator 62 by changing the pressure of the liquid supplied to the liquid supply mechanism 60C. In this embodiment, an example of a configuration in which the amount of swirl (swirl strength) of the swirl flow generated in the swirl flow generator 62 is adjusted using both the pump 87 and the control valve 88 is shown. However, a configuration in which the amount of swirl (swirl strength) of the swirl flow can also be adjusted using only either the pump 87 or the control valve 88.

[0080] Next, a control method (liquid supply method) for a screw compressor according to a second embodiment will be described with reference to Figures 17 and 18. Figure 18 is a characteristic diagram used for controlling a rotation adjustment device (pump or control valve) in the screw compressor according to the second embodiment.

[0081] A control device 90C of a screw compressor 100C shown in FIG. 17 is configured to adjust the pressure of the liquid supplied to a liquid supply mechanism 60C of the compressor body 1 by controlling the delivery pressure of a pump 87 of a liquid supply system 80C and the valve opening of a control valve 88 using a detection value (viscosity of the liquid) from a viscometer 85. This makes it possible to adjust the amount of swirl (swirl strength) of the swirl flow generated by the swirl flow generator 62. The control device 90C adjusts the pressure of the liquid supplied to the liquid supply mechanism 60C by using the characteristic diagram shown in FIG. 18 in addition to the characteristic diagrams shown in FIGS. 14 and 15 used by the control device 90 according to the first embodiment.

[0082] The characteristics diagram shown in Fig. 18 is stored in advance in the storage device 91 of the control device 90C. Fig. 18 is a characteristics diagram showing an example of the relationship between the amount of swirl (strength of swirl) of the swirl flow generated by the liquid supply mechanism 60C and the pressure of the liquid supplied to the liquid supply mechanism 60C. In Fig. 18, the horizontal axis S represents the amount of swirl, and the vertical axis P represents the supply pressure of the liquid.

[0083] Similar to the control device 90 according to the first embodiment, the control device 90C according to the present embodiment estimates the droplet diameter of the liquid generated by the liquid supply mechanism 60C by referring to the characteristic diagram shown in FIG. 14 using the set target viscosity (see the arrow from (1) to (2) in FIG. 14 ). Then, using the calculated droplet diameter, the control device 90C calculates the swirl amount of the swirling flow to be generated by the swirling flow generator 62 by referring to the characteristic diagram shown in FIG. 15 (see the arrow from (2) to (3) in FIG. 15 ). Next, unlike the control device 90 according to the first embodiment, the control device 90C calculates the liquid supply pressure required to generate the calculated swirl amount of the swirling flow by referring to the characteristic diagram shown in FIG. 18 (see the arrow from (3) to (5) in FIG. 18 ). The control device 90C outputs a command for the delivery pressure of the pump 87 or the valve opening of the control valve 88 to the pump 87 or the control valve 88, depending on the calculated supply pressure.

[0084] The control device 90C periodically receives the detection signal (viscosity of the liquid) from the viscometer 85 and sequentially performs the above-mentioned calculations, thereby constantly controlling the delivery pressure of the pump 87 or the valve opening of the control valve 88. This adjusts the diameter of the droplets generated by the liquid being sprayed from the liquid supply mechanism 60C into the working chamber C (storage chamber 45), thereby achieving a balance between the cooling effect of the compressed gas in the working chamber C (compression efficiency) and the degree of deterioration of the atomized liquid (maintenance efficiency).

[0085] As described above, the screw compressor 100C according to the second embodiment includes the compressor body 1 including the male rotor 2 and the female rotor 3 (screw rotors), the storage chamber 45 that rotatably stores the male rotor 2 and the female rotor 3 (screw rotors), and the casing 4 having the liquid supply mechanism 60C that injects liquid into the storage chamber 45, and the liquid supply system 80C that recovers liquid contained in the compressed gas discharged from the compressor body 1 and supplies it to the liquid supply mechanism 60C in the casing 4. The liquid supply mechanism 60C includes an injection hole 61 that opens into the storage chamber 45 and a swirl flow generator 62 that is located upstream of the injection hole 61 and swirls the liquid supplied from the liquid supply system 80C to generate a swirl flow. The liquid supply system 80C includes a pump 87 or a control valve 88 that can adjust the pressure of the liquid supplied to the liquid supply mechanism 60C in the casing 4, as a swirl adjustment device that adjusts the amount of swirl of the swirl flow generated by the swirl flow generator 62.

[0086] According to this configuration, it is possible to adjust the droplet size of the liquid generated by the injection of the liquid supply mechanism 60C by adjusting the amount of swirl of the swirl flow generated by the swirl flow generator 62 using the pump 87 or control valve 88 as a swirl adjustment device. Therefore, it is possible to operate the screw compressor 100C in consideration of both the compression efficiency and maintenance efficiency when turning the liquid to be supplied to the working chamber C in the compressor main body 1 into fine droplets.

[0087] [Gas compressor system] Next, a gas compressor system equipped with a plurality of screw compressors according to an embodiment of the present invention will be described with reference to Figures 19 to 23. In Figures 19 to 23, the same reference numerals as those shown in Figures 1 to 18 denote similar parts, and detailed description thereof will be omitted. Figure 19 is a block diagram showing the configuration of a gas compressor system equipped with a plurality of screw compressors according to an embodiment of the present invention.

[0088] A gas compressor system 110 includes a plurality of liquid-feed screw compressors, and includes at least two of the above-described screw compressors 100 (100C) that are capable of adjusting the swirl amount of the swirl flow generated by the liquid-feed mechanisms 60 and 60C. The gas compressor system 110 shown in FIG. 19 includes, for example, four of the above-described screw compressors 100 (100C) (see FIGS. 1 and 17) that are capable of adjusting the swirl amount of the swirl flow, and includes a monitoring device 120 that monitors each of the screw compressors A, B, C, and D. The monitoring device 120 controls the swirl amount of the swirl flow in each of the screw compressors A, B, C, and D via a control device 90 (90C). The monitoring device 120 is configured, for example, as a host controller of the control devices 90 and 90C. The monitoring device 120 may also function as the control device 90 for each of the screw compressors 100 and 100C.

[0089] In a gas compressor system, if the degree of oil deterioration differs among the screw compressors, it may not be possible to standardize the oil change and maintenance intervals for each screw compressor. If the maintenance intervals for multiple screw compressors differ, the maintenance work hours and costs increase and maintenance efficiency decreases.

[0090] Therefore, the gas compressor system 110 of this embodiment can be configured to adjust the amount of swirl of the swirling flow generated by the liquid supply mechanism 60 (60C) so that the viscosity of the liquid used in each screw compressor A, B, C, and D is approximately the same in all screw compressors A, B, C, and D.

[0091] Furthermore, in the gas compressor system 110 of this embodiment, each screw compressor A, B, C, and D measures the change in viscosity of the liquid over time (see the time-viscosity graph). Each screw compressor A, B, C, and D transmits the measurement result viscosity information (the change in viscosity of the liquid over time) to the monitoring device 120. The change in viscosity of the liquid over time serves as an indicator of the degree of deterioration of the liquid. The monitoring device 120 can be configured to control each screw compressor A, B, C, and D based on the viscosity information of each screw compressor A, B, C, and D so that maintenance such as oil changes can be performed on each screw compressor A, B, C, and D simultaneously. In other words, the monitoring device 120 can individually adjust the viscosity of the liquid in each screw compressor A, B, C, and D by controlling the amount of swirl of the swirl flow generated by the liquid supply mechanism 60 (60C) in each screw compressor A, B, C, and D.

[0092] Furthermore, in gas compressor system 110 of this embodiment, it is also possible to simultaneously detect the power consumption of each of screw compressors A, B, C, and D. Power consumption has a correlation with compression efficiency. In this case, monitoring device 120 can be configured to control each of screw compressors A, B, C, and D based on viscosity information and power consumption information of each of screw compressors A, B, C, and D so as to optimize the overall maintenance efficiency (maintenance costs, etc.) and compression efficiency (power consumption, etc.) of gas compressor system 110.

[0093] Specifically, the monitoring device adjusts the amount of swirl of the swirl flow of each of the screw compressors A, B, C, and D, for example, in accordance with the flowchart shown in Fig. 20. Fig. 20 is a flowchart showing an example of a control procedure of the monitoring device of the gas compressor system shown in Fig. 19.

[0094] 20, the monitoring device 120 first acquires the liquid viscosity information (detection value of viscometer 85) and power consumption measured by each of the screw compressors A, B, C, and D (step S10). The liquid viscosity information of each of the screw compressors A, B, C, and D is different for each unit, as shown in FIG.

[0095] Next, the monitoring device 120 uses the characteristic diagram shown in FIG. 21 to set the target viscosity of the liquid for each of the screw compressors A, B, C, and D so that the overall maintenance efficiency (maintenance costs, etc.) and compression efficiency of the gas compressor system 110 are optimized (step S20). 21 FIG. 19 is a characteristic diagram showing the relationship between the viscosity of the liquid and the compression efficiency in each of the screw compressors A, B, C, and D of the gas compressor system shown in FIG. 21 In the figure, the horizontal axis S represents the amount of swirl of the swirling flow. The vertical axis ν on the left represents the viscosity of the liquid, and the vertical axis E on the right represents the compression efficiency of each screw compressor A, B, C, and D.

[0096] The monitoring device 120 estimates the compression efficiency of each of the screw compressors A, B, C, and D by referring to the characteristic diagram shown in Fig. 21 using the viscosity information of the liquid measured by each of the screw compressors A, B, C, and D (see the arrows from (1) through (3) to (6) in Fig. 18). The monitoring device 120 sets a target viscosity of the liquid for each of the screw compressors A, B, C, and D based on the detected viscosity information and power consumption of each of the screw compressors A, B, C, and D, and the estimated compression efficiency, so as to optimize the overall maintenance efficiency (maintenance costs, etc.) and compression efficiency of the gas compressor system.

[0097] Next, the monitoring device 120 calculates a target droplet diameter for each of the screw compressors A, B, C, and D that corresponds to the period of use of the liquid, based on the set target viscosity for each of the screw compressors A, B, C, and D (step S30). The monitoring device 120 uses, for example, the characteristic diagram shown in FIG. 22. FIG. 22 is a characteristic diagram showing the relationship between the viscosity of the liquid and the droplet diameter. The monitoring device 120 calculates the target droplet diameter by referring to the characteristic diagram shown in FIG. 22 based on the target viscosity.

[0098] Furthermore, the monitoring device 120 calculates the amount of swirl of the swirling flow based on the target droplet diameter obtained as a result of the calculation (step S40). The monitoring device 120 uses, for example, the characteristic diagram shown in FIG. 23. FIG. 23 is a characteristic diagram showing the relationship between the diameter of droplets generated by the liquid supply mechanism and the amount of swirl of the swirling flow. The monitoring device 120 calculates the target amount of swirl, which is the required amount of swirl of the swirling flow, by referring to the characteristic diagram shown in FIG. 23 based on the target droplet diameter obtained as a result of the calculation.

[0099] The monitoring device 120 outputs the calculated target swirl amount for each screw compressor A, B, C, D as a command to each screw compressor A, B, C, D (step S50). As a result, each screw compressor A, B, C, D adjusts the swirl amount of the swirl flow generated by the liquid supply mechanism 60 (60C) based on the target swirl amount command. In the first embodiment, this controls the rotation angle of the swirl adjustment members 66, 66A, 66B of the liquid supply mechanism 60 of the compressor main body 1. In the second embodiment, this controls the delivery pressure of the pump 87 of the liquid supply system 80C or the valve opening of the control valve 88.

[0100] In this way, in a gas compressor system 110 having a plurality of screw compressors 100, 100C according to this embodiment, the change over time in the viscosity of the liquid in each screw compressor 100, 100C is monitored, and the amount of swirl of the swirling flow generated in the liquid supply mechanism 60, 60C of each screw compressor 100, 100C is adjusted based on the relationship between the state of deterioration of the liquid over time in each screw compressor 100, 100C and the compression efficiency, thereby optimizing the balance between the overall maintenance efficiency (related to the maintenance period) and compression efficiency (related to electricity charges, etc.) of the gas compressor system 110.

[0101] As described above, the gas compressor system 110 including a plurality of screw compressors 100, 100C of the embodiment includes a monitoring device 120 that monitors the plurality of screw compressors 100, 100C. The monitoring device 120 is configured to control the plurality of screw compressors 100, 100C so that the viscosities of the liquids in the plurality of screw compressors 100, 100C are all the same. This configuration enables operation that takes into consideration the overall maintenance efficiency of the gas compressor system 110.

[0102] Furthermore, in gas compressor system 110 according to this embodiment, monitoring device 120 is configured to adjust the viscosity of the liquid in each screw compressor based on the detection values ​​of viscometers 85 of all of the screw compressors 100, 100C so that maintenance of the liquid in the multiple screw compressors can be performed at the same time. This configuration enables operation that takes into consideration the overall maintenance efficiency of gas compressor system 110.

[0103] [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. [Explanation of symbols]

[0104] DESCRIPTION OF SYMBOLS 1...Compressor body, 2...Male rotor (screw rotor), 3...Female rotor (screw rotor), 4...Casing, 45...Storage chamber, 60, 60C...Liquid supply mechanism, 61...Injection hole, 62...Swirl flow generator, 621...Swirl chamber, 622...Inlet passage, 63...Swirl adjustment device, 66, 66A, 66B...Swirl adjustment member, 67...Drive device, 68, 68A, 68B...Notch (opening), 80, 80C...Liquid supply system, 85...Viscometer, 87...Pump (swirl adjustment device), 88...Control valve (swirl adjustment device), 90, 90C...Control device, 100, 100C...Screw compressor, 110...Gas compressor system, 120...Monitoring device

Claims

1. a compressor body including a screw rotor and a casing having a storage chamber for rotatably storing the screw rotor and provided with a liquid supply mechanism for injecting liquid into the storage chamber; a liquid supply system that recovers liquid contained in the compressed gas discharged from the compressor body and supplies the liquid to the liquid supply mechanism of the casing, The liquid supply mechanism includes: an injection hole that opens into the storage chamber; a swirl flow generator located upstream of the injection hole and configured to swirl the liquid supplied from the liquid supply system to generate a swirl flow, the liquid supply mechanism includes a swirl adjustment device that adjusts the amount of swirl of the swirl flow generated by the swirl flow generator, the swirl adjustment device is disposed upstream of the swirl flow generator and includes a rotatable swirl adjustment member having an opening that opens into a flow path of the swirl flow generator; The swirl adjustment member is configured so that the opening state of the opening with respect to the flow path of the swirl flow generator changes in accordance with a change in the rotation angle. A screw compressor characterized by:

2. 2. The screw compressor according to claim 1, The swirl adjustment member is configured so that the opening area of ​​the opening relative to the flow path of the swirl flow generator changes monotonically as the rotation angle increases. A screw compressor characterized by:

3. 3. The screw compressor according to claim 2, The swirl flow generator includes: a swirl chamber connected to the injection hole and generating a swirl flow; an introduction passage connected to the swirl chamber and introducing a liquid in a tangential direction of the swirl chamber; the swirl adjustment member is a disk-shaped member that is disposed in the axial direction of the swirl chamber relative to the swirl flow generator, the opening of the swirl adjustment member is formed on an outer peripheral edge portion of the disk-shaped member, has a shape tapered from one end toward the other end in a circumferential direction, and is configured to open into the introduction path of the swirl flow generator, The rotation adjustment member is configured so that the direction from the one end to the other end of the opening coincides with the direction from the inner periphery side to the outer periphery side of the introduction path. A screw compressor characterized by:

4. 2. The screw compressor according to claim 1, The swirl adjustment member is configured so that an opening area of ​​the opening with respect to the flow path of the swirl flow generator falls within a predetermined range with respect to a change in the rotation angle, and so that an opening position of the opening with respect to the flow path of the swirl flow generator moves in accordance with a change in the rotation angle. A screw compressor characterized by:

5. 5. The screw compressor according to claim 4, The swirl flow generator includes: a swirl chamber connected to the injection hole and generating a swirl flow; an introduction passage connected to the swirl chamber and introducing a liquid in a tangential direction of the swirl chamber; the swirl adjustment member is a disk-shaped member that is disposed in the axial direction of the swirl chamber relative to the swirl flow generator, the opening of the swirl adjustment member is formed on the outer peripheral edge of the disk-shaped member, has a fan shape, and is configured to open into the introduction path of the swirl flow generator, The turning adjustment member is configured such that, at a certain turning position, one side of the fan-shaped opening overlaps with the position of the wall surface on the inner circumferential side of the introduction passage, and the other side of the fan-shaped opening crosses the introduction passage. A screw compressor characterized by:

6. 2. The screw compressor according to claim 1, The liquid supply mechanism is a separate structure from the casing and is configured to be detachable from the casing. A screw compressor characterized by:

7. 2. The screw compressor according to claim 1, a viscometer for detecting the viscosity of the liquid supplied to the liquid supply mechanism; a control device for controlling the rotation adjustment device, The control device controls the swirl adjustment device based on the detected value of the viscometer to adjust the amount of swirl of the swirl flow generated by the swirl flow generator. A screw compressor characterized by:

8. 8. The screw compressor according to claim 7, The control device controls the liquid using a characteristic diagram showing the relationship between the droplet diameter and viscosity of the liquid generated by the liquid supply mechanism. A screw compressor characterized by:

9. A gas compressor system including a plurality of screw compressors according to claim 7, a monitoring device for monitoring the plurality of screw compressors, The monitoring device controls the plurality of screw compressors so that the viscosities of the liquids in the plurality of screw compressors are all the same. A gas compressor system comprising:

10. A gas compressor system including a plurality of screw compressors according to claim 7, a monitoring device for monitoring the plurality of screw compressors, The monitoring device adjusts the viscosity of the liquid in each of the screw compressors based on the detected values ​​of the viscometers of all of the screw compressors so that maintenance of the liquid in the plurality of screw compressors can be performed at the same time. A gas compressor system comprising:

11. A liquid supply method for a screw compressor, comprising: a casing having a storage chamber for rotatably storing a screw rotor and provided with a liquid supply mechanism for injecting liquid into the storage chamber; the liquid supply mechanism having a swirling flow generator for swirling the liquid to generate a swirling flow; a viscosity detection step of detecting a viscosity of the liquid supplied to the liquid supply mechanism; a swirl adjustment step of adjusting the amount of swirl of the swirl flow generated by the swirl flow generator based on the viscosity of the liquid detected in the viscosity detection step, In the case where there are a plurality of screw compressors, The turning adjustment step includes: setting a target viscosity for each of the screw compressors based on the viscosities of the liquid in all of the plurality of screw compressors detected in the viscosity detecting step; The amount of rotation is adjusted so as to achieve the target viscosity for each of the screw compressors. A method for supplying liquid to a screw compressor.

12. The liquid supply method for a screw compressor according to claim 11, The swirl adjusting step is carried out by adjusting at least one of the flow rate, velocity distribution, and pressure of the liquid introduced into the swirl flow generator. A method for supplying liquid to a screw compressor.

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