Screw compressor

Abstract

To provide a screw compressor capable of preventing mixing of air and the like into steam in a compression chamber and improving compression performance.SOLUTION: A screw compressor includes: a casing 2 forming a compression chamber with a tooth portion 3 of a male rotor 1; a suction-side bearing 6 rotatably supporting a suction-side shaft portion 4 connected to one axial side of the tooth portion 3 of the male rotor 1; a discharge-side bearing 7 rotatably supporting a discharge-side shaft portion 5 connected to the axially opposite side of the tooth portion 3 of the male rotor 1; suction-side seals 14A, 14B disposed around the suction-side shaft portion 4 so as to be positioned between the compression chamber and the suction-side bearing 6; and discharge-side seals 19A, 19B disposed around the discharge-side shaft portion 5 so as to be positioned between the compression chamber and the discharge-side bearing 7. The screw compressor has a suction-side water supply hole 16 being open toward a suction-side clearance 15 formed around the suction-side shaft portion 4 so as to be adjacent to the compressor chamber without the suction-side seal interposed therebetween to allow water to be supplied the suction-side clearance 15.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a screw compressor for compressing steam.

Background Art

[0002] Patent Document 1 discloses a screw compressor for compressing steam. This screw compressor includes a screw rotor, a casing that houses the screw rotor and forms a compression chamber between the teeth of the screw rotor, a suction-side bearing that rotatably supports a suction-side shaft portion connected to one axial side of the teeth of the screw rotor, a discharge-side bearing that rotatably supports a discharge-side shaft portion connected to the opposite axial side of the teeth of the screw rotor, a plurality of suction-side seals provided around the suction-side shaft portion so as to be located between the compression chamber and the suction-side bearing, and a plurality of discharge-side seals provided around the discharge-side shaft portion so as to be located between the compression chamber and the discharge-side bearing.

[0003] Air or the like exists between the plurality of suction-side seals and is at approximately atmospheric pressure. Therefore, when the screw compressor sucks steam at a pressure lower than atmospheric pressure, there is a risk that air or the like will flow into the compression chamber through the suction-side seal.

[0004] To solve the above problems, the screw compressor of Patent Document 1 has a supply hole that opens to a suction-side shaft seal chamber formed between the suction-side seal closest to the compression chamber and the second-closest suction-side seal, and supplies steam at a pressure higher than atmospheric pressure to the suction-side shaft seal chamber. Thereby, steam is supplied to the suction-side shaft seal chamber through the supply hole and flows into the compression chamber through the suction-side seal. Therefore, it is possible to prevent air or the like from mixing into the steam in the compression chamber.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] In Patent Document 1, as described above, steam flows into the compression chamber through the intake side seal. Furthermore, the presence of the intake side seal suppresses the flow of steam into the compression chamber. However, if water flows into the compression chamber instead of steam, for example, the cooling, sealing, and lubrication of the compression chamber can be improved, thereby enhancing compression performance. In this case, it is preferable not to suppress the flow of water into the compression chamber.

[0007] The object of the present invention is to provide a screw compressor that can prevent air and other substances from mixing with the steam in the compression chamber, while also improving compression performance. [Means for solving the problem]

[0008] To achieve the above objective, the present invention provides a screw rotor, a casing that houses the screw rotor and forms a compression chamber between itself and the teeth of the screw rotor, an intake side bearing that rotatably supports an intake side shaft connected to one axial side of the teeth of the screw rotor, a discharge side bearing that rotatably supports a discharge side shaft connected to the opposite axial side of the teeth of the screw rotor, a plurality of intake side seals provided around the intake side shaft so as to be located between the compression chamber and the intake side bearing, and a plurality of discharge side seals provided around the discharge side shaft so as to be located between the compression chamber and the discharge side bearing. The plurality of intake side seals include a first intake side seal adjacent to the intake side bearing with respect to the intake side gap formed around the intake side shaft portion so as to be adjacent to the compression chamber without the intake side seal interposed, and a second intake side seal spaced further away from the intake side bearing with respect to the first intake side seal. In a screw compressor that compresses steam at a pressure lower than atmospheric pressure, The aforementioned A water supply port on the intake side that opens into the intake gap and supplies water to the intake gap. The suction side drain hole opens to the first suction side shaft seal chamber formed between the first suction side seal and the second suction side seal, and drains water that has leaked from the suction side gap into the first suction side shaft seal chamber through the first suction side seal. to have Furthermore, the suction-side drain hole is positioned above the first suction-side shaft seal chamber. . [Effects of the Invention]

[0009] According to the present invention, it is possible to prevent air and other substances from mixing with the steam in the compression chamber, and to improve the compression performance. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows the cross-sectional structure and related components of a screw compressor in the first embodiment of the present invention. [Figure 2] This figure shows the cross-sectional structure and related components of a screw compressor in a second embodiment of the present invention. [Figure 3] This figure shows the cross-sectional structure and related components of a screw compressor in a first modified example of the present invention. [Figure 4] This figure shows the cross-sectional structure and related components of a screw compressor in a second modified example of the present invention. [Figure 5] This figure shows the cross-sectional structure and related components of a screw compressor in a third modified example of the present invention. [Modes for carrying out the invention]

[0011] A first embodiment of the present invention will be described with reference to Figure 1. Figure 1 is a diagram showing the cross-sectional structure of a screw compressor in this embodiment, along with related equipment.

[0012] The screw compressor of this embodiment comprises a male rotor 1 and a female rotor (not shown), which are screw rotors, and a casing 2 that houses the male rotor 1 and the female rotor. In this embodiment, the axial direction (left-right direction in Figure 1) of the male rotor 1 and the female rotor is horizontal.

[0013] The male rotor 1 has a toothed portion 3 with multiple helical teeth, an intake-side shaft portion 4 connected to one axial side of the toothed portion 3 (left side in Figure 1), and a discharge-side shaft portion 5 connected to the opposite axial side of the toothed portion 3 (right side in Figure 1). The intake-side shaft portion 4 of the male rotor 1 is rotatably supported by an intake-side bearing 6, and the discharge-side shaft portion 5 of the male rotor 1 is rotatably supported by a discharge-side bearing 7. The intake-side bearing 6 is located in the intake-side bearing chamber 8 of the casing 2 and is lubricated by oil stored in the intake-side bearing chamber 8. The discharge-side bearing 7 is located in the discharge-side bearing chamber 9 of the casing 2 and is lubricated by oil stored in the discharge-side bearing chamber 9.

[0014] The female rotor has a tooth portion, a suction-side shaft portion, and a discharge-side shaft portion, similar to the male rotor 1. The tooth portion of the female rotor is adapted to mesh with the tooth portion of the male rotor in contact or non-contact. The suction-side shaft portion of the female rotor is rotatably supported by a suction-side bearing (not shown), and the discharge-side shaft portion of the female rotor is rotatably supported by a discharge-side bearing (not shown). The aforementioned suction-side bearing is disposed in a suction-side bearing chamber (not shown) of the casing 2 and lubricated with oil stored in this suction-side bearing chamber. The aforementioned discharge-side bearing is disposed in a discharge-side bearing chamber (not shown) of the casing 2 and lubricated with oil stored in this discharge-side bearing chamber.

[0015] As shown in the figure, the rotational force of the electric motor 10 is transmitted to the male rotor 1 by directly connecting the suction-side shaft portion 4 of the electric motor 10 and the male rotor 1 or by connecting them via a gear, a belt, or the like. Thereby, the male rotor 1 rotates. Although not shown, the rotational force of the male rotor 1 is transmitted to the female rotor by the tooth portion 3 of the male rotor 1 and the tooth portion of the female rotor coming into contact and meshing, or by the gear provided on the discharge-side shaft portion 5 of the male rotor 1 and the gear provided on the discharge-side shaft portion of the female rotor meshing. Thereby, the female rotor also rotates.

[0016] A plurality of male-rotor-side compression chambers are formed between the tooth portion 3 of the male rotor 1 and the casing 2, and a plurality of female-rotor-side compression chambers are formed between the tooth portion of the female rotor and the casing 2. Each compression chamber changes in volume while moving from one side in the axial direction (the left side in FIG. 1) to the opposite side (the right side in FIG. 1) as the male rotor 1 and the female rotor rotate. Thereby, the vapor is sucked from the suction flow path 11 of the casing 2, compressed, and the compressed vapor is discharged to the discharge flow path 12 of the casing 2. A gas-liquid separator 13 is provided on the downstream side of the discharge flow path 12.

[0017] Incidentally, the screw compressor of the present embodiment sucks steam at a pressure lower than atmospheric pressure, and there is a risk that air or oil may flow into the compression chamber through the suction-side seal described later. Also, the screw compressor of the present embodiment may discharge compressed steam at a pressure lower than atmospheric pressure, and there is a risk that air or oil may flow into the compression chamber through the discharge-side seal described later. As a feature of the screw compressor of the present embodiment for solving the above-described problems, the structure around the suction-side shaft portion 4 and the discharge-side shaft portion 5 of the male rotor 1 will be described.

[0018] The screw compressor of the present embodiment includes suction-side seals 14A and 14B provided around the suction-side shaft portion 4 of the male rotor 1 so as to be positioned between the compression chamber on the male rotor side and the suction-side bearing 6, a suction-side gap 15 formed around the suction-side shaft portion 4 of the male rotor 1 and adjacent to the compression chamber on the male rotor side without the intervention of the suction-side seal, a suction-side water supply hole 16 formed in the casing 2 and opening to the suction-side gap 15, a suction-side shaft seal chamber 17 formed between the suction-side seal 14A and the suction-side seal 14B, and a suction-side drain hole 18 formed in the casing 2 and opening to the suction-side shaft seal chamber 17.

[0019] The suction-side seal 14A is an annular seal such as a lip seal or a mechanical seal, and is adjacent to the suction-side gap 15 on the left side (in FIG. 1) of the suction-side bearing 6. The suction-side seal 14B is an annular seal such as a lip seal or a mechanical seal, and is spaced apart from the suction-side seal 14A on the side of the suction-side bearing 6.

[0020] The screw compressor of the present embodiment includes discharge-side seals 19A and 19B provided around the discharge-side shaft portion 5 of the male rotor 1 so as to be positioned between the compression chamber on the male rotor side and the discharge-side bearing 7, a discharge-side gap 20 formed around the discharge-side shaft portion 5 of the male rotor 1 and adjacent to the compression chamber on the male rotor side without the intervention of the discharge-side seal, a discharge-side water supply hole 21 formed in the casing 2 and opening to the discharge-side gap 20, a discharge-side shaft seal chamber 22 formed between the discharge-side seal 19A and the discharge-side seal 19B, and a discharge-side drain hole 23 formed in the casing 2 and opening to the discharge-side shaft seal chamber 22.

[0021] The discharge side seal 19A is an annular seal, such as a lip seal or a mechanical seal, and is adjacent to the discharge side gap 20 from the discharge side bearing 7 (to the right in Figure 1). The discharge side seal 19B is an annular seal, such as a lip seal or a mechanical seal, and is spaced further away from the discharge side seal 19A from the discharge side bearing 7.

[0022] The screw compressor of this embodiment includes a water supply line 24 connected to the suction-side water supply port 16 and the discharge-side water supply port 21 of the casing 2. The water supply line 24 supplies water from a water source (not shown) to the suction-side water supply port 16 and the discharge-side water supply port 21 of the casing 2 by pressurizing a water pump 25.

[0023] The intake side water supply hole 16 supplies water from the water supply line 24 to the intake side gap 15. As a result, the water supplied to the intake side gap 15 flows into the compression chamber on the male rotor side. In addition, the water supplied to the intake side gap 15 leaks into the intake side shaft seal chamber 17 via the intake side seal 14A. The intake side drain hole 18 discharges the water that has leaked into the intake side shaft seal chamber 17. In this embodiment, the intake side drain hole 18 also discharges lubricating oil that has leaked from the intake side bearing 6 into the intake side shaft seal chamber 17 via the intake side seal 14B.

[0024] In this embodiment, as described above, the water supplied to the intake gap 15 flows into the compression chamber, preventing air and other substances from mixing with the steam in the compression chamber. Furthermore, the inflow of water into the compression chamber improves, for example, the cooling, sealing, and lubrication of the compression chamber, thereby enhancing compression performance. In addition, since there is no intake seal between the intake gap 15 and the compression chamber, the inflow of water into the compression chamber is not inhibited. From this viewpoint as well, compression performance can be enhanced.

[0025] The discharge-side water supply hole 21 supplies water from the water supply line 24 to the discharge-side gap 20. As a result, the water supplied to the discharge-side gap 20 flows into the compression chamber on the male rotor side. In addition, the water supplied to the discharge-side gap 20 leaks into the discharge-side shaft seal chamber 22 via the discharge-side seal 19A. The discharge-side drain hole 23 discharges the water that has leaked into the discharge-side shaft seal chamber 22. In this embodiment, the discharge-side drain hole 23 also discharges lubricating oil that has leaked from the discharge-side bearing 7 into the discharge-side shaft seal chamber 22 via the discharge-side seal 19B.

[0026] In this embodiment, as described above, the water supplied to the discharge gap 20 flows into the compression chamber, preventing air and other substances from mixing with the steam in the compression chamber. Furthermore, the inflow of water into the compression chamber improves, for example, the cooling, sealing, and lubrication of the compression chamber, thereby enhancing compression performance. In addition, since there is no discharge seal between the discharge gap 20 and the compression chamber, the inflow of water into the compression chamber is not inhibited. From this viewpoint as well, compression performance can be enhanced.

[0027] The structure surrounding the intake-side shaft portion and discharge-side shaft portion of the female rotor is the same as the structure surrounding the intake-side shaft portion 4 and discharge-side shaft portion 5 of the male rotor 1 described above. Therefore, although the explanation is omitted, the same features allow the same effect to be obtained.

[0028] In the first embodiment, as shown in Figure 1, the suction-side drain hole 18 is positioned below the suction-side shaft seal chamber 17, and the discharge-side drain hole 23 is positioned below the discharge-side shaft seal chamber 22. However, the invention is not limited to this configuration. The suction-side drain hole 18 may be positioned above the suction-side shaft seal chamber 17, and the discharge-side drain hole 23 may be positioned above the discharge-side shaft seal chamber 22 (see Figure 3, described later). This allows the suction-side shaft seal chamber 17 to be filled with water, preventing air or oil from flowing into the compression chamber via the suction-side seal 14A. Alternatively, the discharge-side shaft seal chamber 22 may be filled with water, preventing air or oil from flowing into the compression chamber via the discharge-side seal 19A.

[0029] Furthermore, in the first embodiment, the water supply line 24 was described as being configured to supply water from the water source to the suction-side water supply port 16 and the discharge-side water supply port 21 of the casing 2 by pressurizing the water pump 25, but it is not limited to this. The water supply line 24 may also be configured to supply water separated by the gas-liquid separator 13 to the suction-side water supply port 16 and the discharge-side water supply port 21 of the casing 2 by the pressure of the gas-liquid separator 13 (see Figure 4 described later). This may reduce water consumption and power consumption.

[0030] A second embodiment of the present invention will be described with reference to Figure 2. Figure 2 is a diagram showing the cross-sectional structure of the screw compressor in this embodiment, along with related equipment. In this embodiment, parts equivalent to those in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted as appropriate.

[0031] The screw compressor of this embodiment has intake side seals 14A, 14B, and 14C provided around the intake side shaft portion 4 of the male rotor 1 so as to be located between the compression chamber on the male rotor side and the intake side bearing 6. The added intake side seal 14C is an annular seal such as a lip seal or a mechanical seal, and is spaced further away from the intake side bearing 6 (to the left in Figure 2) than the intake side seal 14B. The screw compressor of this embodiment also has an intake side shaft seal chamber 17A formed between the intake side seals 14A and 14B, an intake side shaft seal chamber 17B formed between the intake side seals 14B and 14C, and an intake side oil drain hole 26 formed in the casing 2 that opens to the intake side shaft seal chamber 17B. The intake side water drain hole 18 opens to the intake side shaft seal chamber 17A.

[0032] The screw compressor of this embodiment has discharge side seals 19A, 19B, and 19C provided around the discharge side shaft portion 5 of the male rotor 1 so as to be located between the compression chamber on the male rotor side and the discharge side bearing 7. The additional discharge side seal 19C is an annular seal such as a lip seal or a mechanical seal, and is spaced further away from the discharge side bearing 7 (to the right in Figure 2) than the discharge side seal 19B. The screw compressor of this embodiment also has a discharge side shaft seal chamber 22A formed between the discharge side seals 19A and 19B, a discharge side shaft seal chamber 22B formed between the discharge side seals 19B and 19C, and a discharge side oil drain hole 27 formed in the casing 2 and opening to the discharge side shaft seal chamber 22B. The discharge side water drain hole 23 opens to the discharge side shaft seal chamber 22A.

[0033] The water supply line 24 has a water receiver 28 that stores water discharged from the suction-side drain hole 18 and the discharge-side drain hole 23 of the casing 2, and the water stored in the water receiver 28 is supplied to the suction-side water supply hole 16 and the discharge-side water supply hole 21 of the casing 2 by pressurizing the water pump 25.

[0034] The intake side water supply hole 16 supplies water from the water supply line 24 to the intake side gap 15. As a result, the water supplied to the intake side gap 15 flows into the compression chamber on the male rotor side. In addition, the water supplied to the intake side gap 15 leaks into the intake side shaft seal chamber 17A via the intake side seal 14A. The intake side water drain hole 18 discharges the water that has leaked into the intake side shaft seal chamber 17A. The intake side oil drain hole 26 discharges the lubricating oil that has leaked from the intake side bearing 6 into the intake side shaft seal chamber 17B via the intake side seal 14C.

[0035] In this embodiment, as in the first embodiment, the water supplied to the intake gap 15 flows into the compression chamber, preventing air and other substances from mixing with the steam in the compression chamber. Furthermore, the inflow of water into the compression chamber improves, for example, the cooling, sealing, and lubrication of the compression chamber, thereby enhancing compression performance. In addition, since there is no intake seal between the intake gap 15 and the compression chamber, the inflow of water into the compression chamber is not inhibited. From this viewpoint as well, compression performance can be enhanced.

[0036] The discharge-side water supply hole 21 supplies water from the water supply line 24 to the discharge-side gap 20. As a result, the water supplied to the discharge-side gap 20 flows into the compression chamber on the male rotor side. In addition, the water supplied to the discharge-side gap 20 leaks into the discharge-side shaft seal chamber 22A via the discharge-side seal 19A. The discharge-side drain hole 23 discharges the water that has leaked into the discharge-side shaft seal chamber 22A. The discharge-side oil drain hole 27 discharges the lubricating oil that has leaked from the discharge-side bearing 7 into the discharge-side shaft seal chamber 22B via the discharge-side seal 19C.

[0037] In this embodiment, as in the first embodiment, the water supplied to the discharge gap 20 flows into the compression chamber, preventing air and other substances from mixing with the steam in the compression chamber. Furthermore, the inflow of water into the compression chamber improves, for example, the cooling, sealing, and lubrication of the compression chamber, thereby enhancing compression performance. In addition, since there is no discharge seal between the discharge gap 20 and the compression chamber, the inflow of water into the compression chamber is not inhibited. From this viewpoint as well, compression performance can be enhanced.

[0038] The structure surrounding the intake-side shaft portion and discharge-side shaft portion of the female rotor is the same as the structure surrounding the intake-side shaft portion 4 and discharge-side shaft portion 5 of the male rotor 1 described above. Therefore, although the explanation is omitted, the same features allow the same effect to be obtained.

[0039] In the second embodiment, as shown in Figure 2, the suction-side drain hole 18 is positioned below the suction-side shaft seal chamber 17A, and the discharge-side drain hole 23 is positioned below the discharge-side shaft seal chamber 22A. However, the invention is not limited to this. As shown in the modified example in Figure 3, the suction-side drain hole 18 may be positioned above the suction-side shaft seal chamber 17A, and the discharge-side drain hole 23 may be positioned above the discharge-side shaft seal chamber 22A. This allows the suction-side shaft seal chamber 17A to be filled with water, preventing air or oil from flowing into the compression chamber via the suction-side seal 14A. Alternatively, the discharge-side shaft seal chamber 22A may be filled with water, preventing air or oil from flowing into the compression chamber via the discharge-side seal 19A.

[0040] Furthermore, in the first embodiment, the water supply line 24 was described as being configured to supply water discharged from the suction-side drain hole 18 and discharge-side drain hole 23 of the casing 2 to the suction-side water supply hole 16 and discharge-side water supply hole 21 of the casing 2 by pressurization by the water pump 25, but it is not limited to this. As shown in the modified example in Figure 4, the water supply line 24 may be configured to supply water separated by the gas-liquid separator 13 to the suction-side water supply hole 16 and discharge-side water supply hole 21 of the casing 2 by the pressure of the gas-liquid separator 13. This may reduce water consumption and power consumption.

[0041] Furthermore, in the second embodiment, although not specifically described, as shown in the modified example in Figure 5, the screw compressor may be equipped with an oil supply line 29 that supplies oil discharged from the suction-side oil drain hole 26 and the discharge-side oil drain hole 27 of the casing 2 to the suction-side bearing 6 and the discharge-side bearing 7. The oil supply line 29 has an oil receiver 30 that stores the oil discharged from the suction-side oil drain hole 26 and the discharge-side oil drain hole 27 of the casing 2, and the oil stored in the oil receiver 30 is supplied to the suction-side bearing chamber 8 and the discharge-side bearing chamber 9 of the casing 2 by pressurization by an oil pump 31. This may reduce oil consumption.

[0042] Furthermore, the screw compressors of the first and second embodiments and their modifications may discharge compressed steam at a pressure lower than atmospheric pressure, and in order to solve the problem that air or oil may flow into the compression chamber through the discharge side seal, the invention has been described using the example of having a discharge side water supply hole 21 and a discharge side drain hole 23, but it is not limited to this. If the screw compressor discharges compressed steam at a pressure higher than atmospheric pressure, it does not need to have a discharge side water supply hole 21 and a discharge side drain hole 23.

[0043] In the above description, the present invention has been explained using the example of applying it to a screw compressor equipped with two screw rotors, but it is not limited to this. The present invention may also be applied to a screw compressor equipped with one or three or more screw rotors. [Explanation of symbols]

[0044] 1 Male rotor (screw rotor) 2 Casing 3. Teeth 4. Intake side shaft 5 Discharge side shaft 6 Suction side bearing 7 Discharge side bearing 13 Gas-liquid separator 14A, 14B, 14C Intake side seal 15. Intake side gap 16 Suction side water supply hole 17,17A,17B Suction side shaft sealing chamber 18 Intake side drain hole 19A, 19B, 19C Discharge side seal 20 Discharge side gap 21 Discharge side water supply hole 22,22A,22B Discharge side shaft sealing chamber 23 Discharge side drain hole 24 Water supply lines 26 Intake side oil drain hole 27 Discharge side oil drain hole 29 Fueling line

Claims

1. The device comprises a screw rotor, a casing housing the screw rotor and forming a compression chamber between itself and the teeth of the screw rotor, an intake-side bearing rotatably supporting an intake-side shaft connected to one axial side of the teeth of the screw rotor, a discharge-side bearing rotatably supporting a discharge-side shaft connected to the opposite axial side of the teeth of the screw rotor, a plurality of intake-side seals provided around the intake-side shaft so as to be located between the compression chamber and the intake-side bearing, and a plurality of discharge-side seals provided around the discharge-side shaft so as to be located between the compression chamber and the discharge-side bearing. The plurality of intake side seals include a first intake side seal adjacent to the intake side bearing with respect to the intake side gap formed around the intake side shaft portion so as to be adjacent to the compression chamber without the intake side seal interposed, and a second intake side seal spaced further away from the intake side bearing with respect to the first intake side seal. In a screw compressor that compresses steam at a pressure lower than atmospheric pressure, An intake-side water supply port that opens to the intake-side gap and supplies water to the intake-side gap, It has an intake side drain hole that opens to a first intake side shaft seal chamber formed between the first intake side seal and the second intake side seal, and discharges water that has leaked from the intake side gap into the first intake side shaft seal chamber through the first intake side seal, A screw compressor characterized in that the suction-side drain hole is positioned above the first suction-side shaft seal chamber.

2. In the screw compressor according to claim 1, The plurality of intake side seals include a third intake side seal that is spaced further away from the intake side bearing than the second intake side seal. A screw compressor characterized by having an intake side oil drain hole that opens to a second intake side shaft seal chamber formed between the second intake side seal and the third intake side seal, and for discharging lubricating oil that has leaked from the intake side bearing into the second intake side shaft seal chamber via the third intake side seal.

3. In the screw compressor according to claim 1, A screw compressor characterized by having a water supply line that supplies water discharged from the suction-side drain hole to the suction-side water supply hole.

4. In the screw compressor according to claim 1, A gas-liquid separator separates the compressed steam discharged from the compression chamber from the water contained therein. A screw compressor characterized by having a water supply line that supplies water separated by the gas-liquid separator to the suction-side water supply port.

5. In the screw compressor according to claim 2, A screw compressor characterized by having an oil supply line that supplies oil discharged from the suction-side oil drain hole to the suction-side bearing.

6. In the screw compressor according to claim 1, The plurality of discharge-side seals include a first discharge-side seal adjacent to the discharge-side bearing with respect to a discharge-side gap formed around the discharge-side shaft portion so as to be adjacent to the compression chamber without the presence of the discharge-side seal, and a second discharge-side seal spaced further away from the discharge-side bearing than the first discharge-side seal. A discharge-side water supply hole that opens to the discharge-side gap and supplies water to the discharge-side gap, It has a discharge side drain hole that opens to a first discharge side shaft seal chamber formed between the first discharge side seal and the second discharge side seal, and discharges water that has leaked from the discharge side gap into the first discharge side shaft seal chamber through the first discharge side seal, A screw compressor characterized in that the discharge side drain hole is positioned above the first discharge side shaft seal chamber.

7. In the screw compressor according to claim 6, The plurality of discharge-side seals include a third discharge-side seal that is spaced further away from the discharge-side bearing than the second discharge-side seal. A screw compressor characterized by having a discharge-side oil drain hole that opens to a second discharge-side shaft seal chamber formed between the second discharge-side seal and the third discharge-side seal, and for draining lubricating oil that has leaked from the discharge-side bearing into the second discharge-side shaft seal chamber via the third discharge-side seal.

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