Two-stage oil-free screw compressor

Abstract

To simplify a configuration of an oil flow passage in a two-stage oil-free screw compressor.SOLUTION: A two-stage oil-free screw compressor 1 comprises: a low-pressure stage casing 31 that defines a low-pressure stage compression chamber R1 for compressing fluid; a low-pressure stage compressor body 30 having a low-pressure stage cooling jacket 32 provided in the low-pressure stage casing 31; a high-pressure stage casing 41 that defines a high-pressure stage compression chamber R2 for compressing compressed air discharged from the low-pressure stage compressor body 30; a high-pressure stage compressor body 40 having a high-pressure stage cooling jacket 42 provided in the high-pressure stage casing 41; an oil cooler 52 that cools oil; and an oil flow path 3 in which the high-pressure stage cooling jacket 42, the oil cooler 52, and the low-pressure stage cooling jacket 32 are connected in series in this order and through which the oil flows.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a two-stage oil-free screw compressor. [Background technology]

[0002] The two-stage oil-free screw compressor has a low-pressure stage compressor body and a high-pressure stage compressor body, and compresses air in two stages. The low-pressure stage compressor body and the high-pressure stage compressor body have a pair of male and female screw rotors that can rotate without contact and without oil. In the two-stage oil-free screw compressor, oil is not supplied to the compression chamber, but oil is supplied to the drive mechanism such as gears and bearings that drive the pair of male and female screw rotors. The oil becomes hot due to the effect of compression heat, so it is cooled by an oil cooler. For example, Patent Document 1 discloses such a two-stage oil-free screw compressor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-113237 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the two-stage oil-free screw compressor of Patent Document 1, the oil flow path branches from the oil cooler to the low-pressure stage compressor body and the high-pressure stage compressor body. Therefore, the configuration of the oil flow path becomes complicated, and it is considered that a lot of power is required to make the oil flow due to the complicated flow.

[0005] An object of the present invention is to simplify the configuration of an oil flow path in a two-stage oil-free screw compressor. [Means for solving the problem]

[0006] The present invention relates to A low-pressure stage compressor body having a low-pressure stage casing that defines a low-pressure stage compression chamber that compresses a sucked fluid, and a low-pressure stage cooling jacket provided in the low-pressure stage casing; a high-pressure stage casing that defines a high-pressure stage compression chamber that compresses a compressed fluid discharged from the low-pressure stage compressor body, and a high-pressure stage cooling jacket that is provided in the high-pressure stage casing; An oil cooler for cooling the oil; the high-pressure stage cooling jacket, the oil cooler, and the low-pressure stage cooling jacket are connected in series in this order; and The present invention provides a two-stage oil-free screw compressor comprising:

[0007] According to this configuration, the oil flow path is connected in series in the order of the high-pressure stage cooling jacket, the oil cooler, and the low-pressure stage cooling jacket, so that the oil flow path can be configured as a single route without branching. Therefore, the configuration of the oil flow path can be simplified, and the power required to flow the oil can be reduced. This also makes it possible to reduce the capacity of the oil pump, which is the power to flow the oil, compared to when the oil flow path is branched.

[0008] The oil cooler may have an oil inlet at one end and an oil outlet at the other end in a longitudinal direction, The high-pressure stage compressor body may be disposed closer to the oil inlet than to the oil outlet, The low-pressure stage compressor body may be disposed closer to the oil outlet than to the oil inlet.

[0009] According to this configuration, the piping constituting the oil flow path between the low-pressure stage compressor body (low-pressure stage cooling jacket) and the oil cooler and the piping constituting the oil flow path between the high-pressure stage compressor body (high-pressure stage cooling jacket) and the oil cooler can be shortened, so that the oil flow path can be shortened.

[0010] The two-stage oil-free screw compressor is a low-pressure stage gas cooler that cools the compressed air discharged from the low-pressure stage compressor body; a high-pressure stage gas cooler that cools the compressed air discharged from the high-pressure stage compressor body; and The low-pressure stage compressor body may be disposed closer to the oil cooler than the low-pressure stage gas cooler, The high-pressure stage compressor body may be disposed closer to the oil cooler than the high-pressure stage gas cooler.

[0011] According to this configuration, the low-pressure stage compressor body and the high-pressure stage compressor body can be disposed closer to the oil cooler than the low-pressure stage gas cooler and the high-pressure stage gas cooler. In other words, when considering whether to shorten the compressed air flow path or the oil flow path, the oil flow path is selected to be shortened. This reduces the power required to flow the oil.

[0012] The two-stage oil-free screw compressor may further include an outer box that houses the low-pressure stage compressor body, the high-pressure stage compressor body, the oil cooler, the low-pressure stage gas cooler, and the low-pressure stage gas cooler, The oil cooler, the low-pressure stage gas cooler, and the high-pressure stage gas cooler may be arranged side by side in a horizontal direction and may be air-cooled heat exchangers through which cooling air passes in a vertical direction, The oil cooler, the low-pressure stage gas cooler, and the high-pressure stage gas cooler may be disposed immediately below an exhaust port provided in an upper wall of the exterior box.

[0013] With this configuration, the cooling air passing through the oil cooler, the low-pressure stage gas cooler, and the high-pressure stage gas cooler in the vertical direction does not interfere with each other, so high cooling efficiency can be achieved. Also, the cooling air that has passed through the oil cooler, the low-pressure stage gas cooler, and the high-pressure stage gas cooler and has become hot is immediately exhausted from the exhaust port, so that the temperature rise inside the exterior box can be suppressed.

[0014] The two-stage oil-free screw compressor is a motor that drives the low-pressure stage compressor body and the high-pressure stage compressor body; a gear box that stores gears that transmit driving force from the motor to the low-pressure stage compressor body and the high-pressure stage compressor body; an oil filter disposed adjacent to the gearbox and configured to filter the oil exiting the low-pressure stage cooling jacket; and The gearbox may be disposed downstream of the oil filter in the oil flow path.

[0015] With this configuration, clean oil that has been filtered out by the oil filter can be supplied to the gear box (internal gears), thereby preventing failure of the drive mechanism due to foreign matter. Also, since the oil filter is located adjacent to the gear box, the oil flow path can be made short. Here, "adjacent" includes not only being located next to the gear box, but also being directly in contact with the gear box. Effect of the Invention

[0016] According to the present invention, the configuration of the oil flow passages in a two-stage oil-free screw compressor can be simplified. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a perspective view of a two-stage oil-free screw compressor according to one embodiment. [Diagram 2] FIG. 2 is a perspective view of a two-stage oil-free screw compressor seen from a different angle than FIG. 1 . [Diagram 3] FIG. 2 is a front view of the two-stage oil-free screw compressor of FIG. 1. [Figure 4] FIG. 2 is a right side view of the two-stage oil-free screw compressor of FIG. 1. [Diagram 5] FIG. 2 is a schematic configuration diagram of a compressed air flow path, an oil flow path, and a cooling air flow path. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0019] 1 to 4, a two-stage oil-free screw compressor 1 compresses a fluid in two stages. In the following, air is used as an example of the fluid to be compressed, but the fluid is not limited to air and may be any fluid.

[0020] 1 to 4, the X direction indicates the left-right direction (arrow points to the right), the Y direction indicates the front-rear direction (arrow points forward), and the Z direction indicates the up-down direction (arrow points upward). However, these directions are specified for the convenience of explanation.

[0021] In the two-stage oil-free screw compressor 1 of this embodiment, each component is housed in an outer box 10. The outer box 10 is also generally called a package. In addition, in Figs. 1 to 4, the outer box 10 is partially shown by dashed lines to show the inside of the outer box 10.

[0022] The outer box 10 constitutes the outer surface of the two-stage oil-free screw compressor 1. For example, the outer box 10 is a metal box having a rectangular parallelepiped shape. The outer box 10 has an upper wall 11 and a lower wall 12 that face each other in the vertical direction, a left wall 14 and a right wall 13 that face each other in the left-right direction, and a front wall 16 and a rear wall 15 that face each other in the front-rear direction. The right wall 13 is provided with an intake port 13a (see the tip of the dashed-dotted arrow indicating the air flow) that draws in the air to be compressed. The left wall 14 is provided with an exhaust port (not shown) that discharges the compressed air. The lower part of the left wall 14 is provided with an intake port 14a (see the tip of the dashed-dotted arrow indicating the air flow) that draws in cooling air. The upper wall 11 is provided with an exhaust port 11a (see the base of the dashed-dotted arrow indicating the air flow) that discharges the high-temperature cooling air.

[0023] A motor 20 is disposed in the lower center of the exterior box 10. Cooling air drawn in from the suction port 14a is blown toward the motor 20 by a fan (not shown), thereby cooling the motor 20.

[0024] A gear box 21 that houses gears is mechanically connected to the motor 20. The gear box 21 is disposed adjacent to the motor 20. The low-pressure stage compressor body 30 and the high-pressure stage compressor body 40 are also mechanically connected to the gear box 21. The driving force of the motor 20 is transmitted to the low-pressure stage compressor body 30 and the high-pressure stage compressor body 40 via gears in the gear box 21. In addition, a lower portion of the gear box 21 serves as an oil reservoir 21a in which oil, which will be described later, is stored.

[0025] The low-pressure stage compressor body 30 and the high-pressure stage compressor body 40 are arranged side by side adjacent to each other on the side of the gear box 21. The low-pressure stage compressor body 30 and the high-pressure stage compressor body 40 are arranged side by side in the front-rear direction at the lower left side in the exterior box 10 so that the axial direction (the direction in which the rotation axis of a screw rotor described later extends) coincides with the left-right direction.

[0026] The low-pressure stage compressor body 30 is a part that performs the first stage compression and pressurizes atmospheric air to a certain degree. The low-pressure stage compressor body 30 is fluidly connected to the suction port 13a provided in the right wall 13. The low-pressure stage compressor body 30 has a low-pressure stage casing 31 that defines a low-pressure stage compression chamber R1 that compresses the sucked air, and a low-pressure stage cooling jacket 32 ​​that is provided in the low-pressure stage casing 31 and has a cooling function by the flow of cooling oil. In addition, the low-pressure stage casing 31 is provided with a low-pressure stage intake port 33 for intake and a low-pressure stage discharge port 34 for discharge. The oil inlet and oil outlet of the low-pressure stage cooling jacket 32 ​​are provided on the sides of the low-pressure stage casing 31 and in positions close to the front wall 16.

[0027] A pair of male and female screw rotors are arranged in the low-pressure stage compression chamber R1. The pair of male and female screw rotors are rotatably supported by bearings. The pair of male and female screw rotors are driven by the motor 20 via gears stored in the gear box 21 to compress the air sucked into the low-pressure stage compression chamber R1. Here, the gears in the gear box 21 and the bearings that support the pair of male and female screw rotors are also referred to as the drive mechanism. In the two-stage oil-free screw compressor 1, no oil is supplied into the low-pressure stage compression chamber R1, but lubricating oil is supplied to the drive mechanism, and cooling oil is supplied to the low-pressure stage cooling jacket 32. This is also the case with the high-pressure stage compressor body 40 described below.

[0028] The high-pressure stage compressor body 40 is a part that performs the second stage compression, and further increases the pressure of air that is higher than atmospheric pressure. The high-pressure stage compressor body 40 has a high-pressure stage casing 41 that defines a high-pressure stage compression chamber R2 that compresses the compressed air discharged from the low-pressure stage compressor body 30, and a high-pressure stage cooling jacket 42 that is provided in the high-pressure stage casing 41 and has a cooling function due to the flow of cooling oil. In addition, the high-pressure stage casing 41 is provided with a high-pressure stage intake port 43 for suction and a high-pressure stage discharge port 44 for discharge. The oil inlet and oil outlet of the high-pressure stage cooling jacket 42 are provided on the sides of the high-pressure stage casing 41, close to the rear wall 15.

[0029] A pair of male and female screw rotors are arranged in the high-pressure stage compression chamber R2. The pair of male and female screw rotors are rotatably supported by bearings. The pair of male and female screw rotors are driven by a motor 20 via a gear housed in a gear box 21, thereby compressing the air sucked into the high-pressure stage compression chamber R2.

[0030] A low-pressure stage gas cooler 50, a high-pressure stage gas cooler 51, and an oil cooler 52 are arranged in the upper part of the exterior box 10. The low-pressure stage gas cooler 50, the high-pressure stage gas cooler 51, and the oil cooler 52 are arranged in a horizontal direction (specifically, in the left-right direction) directly below the exhaust port 11a of the upper wall 11. The high-pressure stage gas cooler 51, the low-pressure stage gas cooler 50, and the oil cooler 52 are arranged in this order from left to right. Therefore, the low-pressure stage compressor body 30 is arranged closer to the oil cooler 52 than the low-pressure stage gas cooler 50. The high-pressure stage compressor body 40 is arranged closer to the oil cooler 52 than the high-pressure stage gas cooler 51.

[0031] In this embodiment, the low-pressure stage gas cooler 50, the high-pressure stage gas cooler 51, and the oil cooler 52 are air-cooled heat exchangers through which cooling air passes in the vertical direction. Note that, although the low-pressure stage gas cooler 50, the high-pressure stage gas cooler 51, and the oil cooler 52 are shown in Figs. 1 to 4 as generally rectangular parallelepipeds, they are actually configured so that air can pass from bottom to top.

[0032] The low-pressure stage gas cooler 50 is fluidly connected to the low-pressure stage compressor body 30 and the high-pressure stage compressor body 40. The low-pressure stage gas cooler 50 has an air inlet 50a for compressed air, which is a fluid to be cooled, at one end (the front end in this embodiment) and an air outlet 50b for compressed air, which is a fluid to be cooled, at the other end (the rear end in this embodiment) in the longitudinal direction (the front-rear direction in this embodiment). The compressed air discharged from the low-pressure stage compressor body 30 enters the low-pressure stage gas cooler 50 from the air inlet 50a, is cooled by the low-pressure stage gas cooler 50, exits the low-pressure stage gas cooler 50 from the air outlet 50b, and flows to the high-pressure stage compressor body 40.

[0033] The high-pressure stage gas cooler 51 is fluidly connected to the high-pressure stage compressor body 40 and a discharge port (not shown). The high-pressure stage gas cooler 51 has an air outlet 51b for compressed air, which is a fluid to be cooled, at one end (front end in this embodiment) and an air inlet 51a for compressed air, which is a fluid to be cooled, at the other end (rear end in this embodiment) in the longitudinal direction (front-rear direction in this embodiment). The compressed air discharged from the high-pressure stage compressor body 40 enters the high-pressure stage gas cooler 51 from the air inlet 51a, is cooled by the high-pressure stage gas cooler 51, exits the high-pressure stage gas cooler 51 from the air outlet 51b, and is sent to an arbitrary supply destination from the discharge port of the outer box 10.

[0034] The oil cooler 52 is fluidly connected to the low-pressure stage cooling jacket 32 ​​and the high-pressure stage cooling jacket 42. The oil cooler 52 has an oil inlet 52a at one end (rear end in this embodiment) and an oil outlet 52b at the other end (front end in this embodiment) in the longitudinal direction (front-rear direction in this embodiment). In this embodiment, the high-pressure stage compressor body 40 is disposed closer to the oil inlet 52a than the oil outlet 52b. The low-pressure stage compressor body 30 is disposed closer to the oil outlet 52b than the oil inlet 52a. The oil coming out of the high-pressure stage cooling jacket 42 of the high-pressure stage compressor body 40 enters the oil cooler 52 from the oil inlet 52a. The oil is cooled by the oil cooler 52, exits from the oil outlet 52b, and flows into the low-pressure stage cooling jacket 32 ​​of the low-pressure stage compressor body 30. That is, the high-pressure stage cooling jacket 42, the oil cooler 52, and the low-pressure stage cooling jacket 32 ​​are connected in series in this order to form a part of the oil flow path 3 through which the oil flows. In this embodiment, the oil cooler 52 is provided only between the high-pressure stage cooling jacket 42 and the low-pressure stage cooling jacket 32, that is, no oil cooler is provided upstream of the high-pressure stage cooling jacket 42.

[0035] An oil filter 60 is disposed adjacent to the low-pressure stage compressor body 30. The oil filter 60 filters the oil discharged from the low-pressure stage cooling jacket 32 ​​and removes foreign matter from the oil. The oil filter 60 is disposed adjacent to the gear box 21, and the oil discharged from the oil filter 60 is supplied to the gear box 21 to lubricate the above-mentioned drive mechanism. That is, in the oil flow path 3, the gear box 21 is disposed downstream of the oil filter 60. In this embodiment, no intermediate object is provided between the gear box 21 and the oil filter 60.

[0036] The flow of oil in the oil flow passage 3 is controlled by an oil pump 70 disposed in the lower portion of the outer box 10 near the rear wall 15. The oil pump 70 is disposed below the motor 20 and near the gear box 21. The oil pump 70 is fluidly connected to the oil reservoir 21a and the high-pressure stage cooling jacket 42. Oil flows from the oil reservoir 21a through the oil pump 70 to the high-pressure stage cooling jacket 42.

[0037] In the vertical direction, the low-pressure stage gas cooler 50, the high-pressure stage gas cooler 51, and the oil cooler 52 are all located above the motor 20, and a duct 80 is disposed between the low-pressure stage gas cooler 50, the high-pressure stage gas cooler 51, and the oil cooler 52 and the motor 20. In the illustrated example, the duct 80 has a rectangular cylindrical shape extending in the vertical direction, but the rear surface is shown partially see-through so that the inside can be seen.

[0038] A blower fan 81 is disposed in the duct 80. The blower fan 81 blows the cooling air drawn into the interior of the exterior box 10 from the suction port 14a from bottom to top. Thus, the blower fan 81 blows the cooling air through the duct 80 to the low-pressure stage gas cooler 50, the high-pressure stage gas cooler 51, and the oil cooler 52.

[0039] 5, the two-stage oil-free screw compressor 1 having the above-mentioned configuration is configured with a compressed air passage 2, an oil passage 3, and a cooling air passage 4. In Fig. 5, the compressed air passage 2 is indicated by a dashed line arrow, the oil passage 3 is indicated by a broken line arrow, and the cooling air passage 4 is indicated by a thick line arrow.

[0040] In the compressed air flow path 2, air outside the outer box 10 flows from the suction port 13a to the low-pressure stage intake port 33 of the low-pressure stage compressor body 30. The air is sucked into the low-pressure stage compressor body 30 from the low-pressure stage intake port 33, compressed in the low-pressure stage compression chamber R1, and discharged as compressed air from the low-pressure stage discharge port 34. The compressed air discharged from the low-pressure stage discharge port 34 has a high temperature due to the heat of compression. The high-temperature compressed air flows to the low-pressure stage gas cooler 50 and is cooled by the low-pressure stage gas cooler 50. The cooled compressed air flows to the high-pressure stage intake port 43 of the high-pressure stage compressor body 40. The compressed air is sucked into the high-pressure stage compressor body 40 from the high-pressure stage intake port 43, compressed in the high-pressure stage compression chamber R2, and discharged from the high-pressure stage discharge port 44. The compressed air discharged from the high-pressure stage discharge port 44 has a high temperature due to the heat of compression. The hot compressed air flows to the high-pressure stage gas cooler 51, where it is cooled and sent to any desired destination.

[0041] In the oil flow path 3, the oil stored in the oil reservoir 21a flows from the oil pump 70 to the high-pressure stage cooling jacket 42 to cool the high-pressure stage compressor body 40. The oil coming out of the high-pressure stage cooling jacket 42 is at a high temperature. The high-temperature oil flows to the oil cooler 52 and is cooled by the oil cooler 52. The cooled oil flows to the low-pressure stage cooling jacket 32 ​​and cools the low-pressure stage compressor body 30. The oil coming out of the low-pressure stage cooling jacket 32 ​​is at a high temperature, but is at a low temperature compared to the oil coming out of the high-pressure stage cooling jacket 42 and still has a cooling capacity. The oil coming out of the low-pressure stage cooling jacket 32 ​​flows to the oil filter 60. The oil has impurities removed by the oil filter 60 and flows to the gear box 21. The oil that has entered the gear box 21 lubricates the drive mechanism. The oil used for lubrication is stored in the oil reservoir 21a of the gear box 21 and flows to the oil pump 70. Then, the oil flows again from the oil pump 70 to the high-pressure stage cooling jacket 42, cools the high-pressure stage compressor body 40, and thereafter repeats the same flow pattern. In this manner, the oil flow path 3 is configured to circulate in a single flow path without branching. That is, the oil flow path 3 is configured to return the oil delivered from the oil pump 70 to the oil reservoir 21a of the gear box 21 after supplying the oil to various oil supply points that require cooling or lubrication.

[0042] In the cooling air flow path 4, cooling air outside the outer box 10 is sucked in from the suction port 14a and blown toward the motor 20 by the motor fan to cool the motor 20. The cooling air that has cooled the motor 20 is blown upward through the duct 80 by the blower fan 81 and passes through the low-pressure stage gas cooler 50, the high-pressure stage gas cooler 51, and the oil cooler 52. In the low-pressure stage gas cooler 50, the cooling air cools the compressed air discharged from the low-pressure stage compressor body 30. In the high-pressure stage gas cooler 51, the cooling air cools the compressed air discharged from the high-pressure stage compressor body 40. In the oil cooler 52, the cooling air cools the oil. The cooling air that has passed through the low-pressure stage gas cooler 50, the high-pressure stage gas cooler 51, and the oil cooler 52 is at a high temperature. The high-temperature cooling air is exhausted to the outside of the outer box 10 from the exhaust port 11a.

[0043] According to the two-stage oil-free screw compressor 1 of the present embodiment, the following operational effects are achieved.

[0044] Since the oil flow path 3 is connected in series with the high-pressure stage cooling jacket 42, the oil cooler 52, and the low-pressure stage cooling jacket 32 ​​in that order, the oil flow path 3 can be configured as a single route without branching. Therefore, the configuration of the oil flow path 3 can be simplified and the power required to flow the oil can be reduced. This also makes it possible to reduce the capacity of the oil pump 70, which is the power that flows the oil, compared to when the oil flow path is branched.

[0045] In addition, since the piping constituting the oil flow path 3 between the low-pressure stage compressor main body 30 (low-pressure stage cooling jacket 32) and the oil cooler 52 and the piping constituting the oil flow path between the high-pressure stage compressor main body 40 (high-pressure stage cooling jacket 42) and the oil cooler 52 can be shortened, the oil flow path 3 can be shortened.

[0046] In addition, the low-pressure stage compressor body 30 and the high-pressure stage compressor body 40 can be disposed closer to the oil cooler 52 than the low-pressure stage gas cooler 50 and the high-pressure stage gas cooler 51. In other words, when considering whether to shorten the compressed air passage 2 or the oil passage 3, the selection is made to shorten the oil passage 3. This makes it possible to reduce the power required to flow the oil.

[0047] In addition, since clean oil that has had impurities filtered out by the oil filter 60 can be supplied to the gear box 21 (internal gears), breakdowns in the drive mechanism due to impurities can be suppressed. In addition, since the oil filter 60 is disposed adjacent to the gear box 21, the oil flow path 3 can be configured to be short.

[0048] In addition, since the oil cooler 52, the low-pressure stage gas cooler 50, and the high-pressure stage gas cooler 51 are arranged in a horizontal direction, the cooling air passing through them in the vertical direction does not interfere with each other. Therefore, high cooling efficiency can be achieved. In addition, the cooling air that has passed through the oil cooler 52, the low-pressure stage gas cooler 50, and the high-pressure stage gas cooler 51 and has become hot is immediately exhausted from the exhaust port 11a, so that the temperature rise inside the exterior box can be suppressed.

[0049] Although specific embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention.

[0050] The present disclosure may include the following aspects. (Aspect 1) A low-pressure stage compressor body having a low-pressure stage casing that defines a low-pressure stage compression chamber that compresses a sucked fluid, and a low-pressure stage cooling jacket provided in the low-pressure stage casing; a high-pressure stage casing that defines a high-pressure stage compression chamber that compresses a compressed fluid discharged from the low-pressure stage compressor body, and a high-pressure stage cooling jacket that is provided in the high-pressure stage casing; a motor that drives the low-pressure stage compressor body and the high-pressure stage compressor body; An oil cooler for cooling the oil; an exterior box that houses the low-pressure stage compressor body, the high-pressure stage compressor body, the motor, and the oil cooler; the high-pressure stage cooling jacket, the oil cooler, and the low-pressure stage cooling jacket are connected in series in this order; and A two-stage oil-free screw compressor equipped with (Aspect 2) The oil cooler has an oil inlet at one end and an oil outlet at the other end in a longitudinal direction, The high-pressure stage compressor body is disposed closer to the oil inlet than to the oil outlet, 2. The two-stage oil-free screw compressor according to aspect 1, wherein the low-pressure stage compressor body is disposed closer to the oil outlet than to the oil inlet. (Aspect 3) a low-pressure stage gas cooler that cools the compressed air discharged from the low-pressure stage compressor body; a high-pressure stage gas cooler that cools the compressed air discharged from the high-pressure stage compressor body; Further equipped with The low-pressure stage compressor body is disposed closer to the oil cooler than the low-pressure stage gas cooler, 3. The two-stage oil-free screw compressor according to aspect 1 or 2, wherein the high-pressure stage compressor body is disposed closer to the oil cooler than the high-pressure stage gas cooler. (Aspect 4) the oil cooler, the low-pressure stage gas cooler, and the high-pressure stage gas cooler are arranged side by side in a horizontal direction, and are air-cooled heat exchangers through which cooling air passes in a vertical direction; The two-stage oil-free screw compressor according to aspect 3, wherein the oil cooler, the low-pressure stage gas cooler, and the high-pressure stage gas cooler are disposed immediately below an exhaust port provided in an upper wall of the outer box. (Aspect 5) a gear box that stores gears that transmit driving force from the motor to the low-pressure stage compressor body and the high-pressure stage compressor body; an oil filter disposed adjacent to the gearbox and configured to remove impurities from the oil exiting the low pressure stage cooling jacket; Further equipped with 5. The two-stage oil-free screw compressor according to any one of aspects 1 to 4, wherein the gear box is disposed downstream of the oil filter in the oil flow path. [Explanation of symbols]

[0051] 1. Two-stage oil-free screw compressor 2 Compressed air flow path 3 Oil flow path 4 Cooling air passage 10 Outer box 11 Upper wall 11a Exhaust port 12 Lower wall 13 Right wall 13a Intake port 14 Left Wall 14a Intake port 15 Back wall 16 Front wall 20 Motor 21 Gear Box 21a Oil storage section 30 Low pressure stage compressor body 31 Low pressure stage casing 32 Low pressure stage cooling jacket 33 Low pressure stage intake 34 Low pressure stage outlet 40 High pressure stage compressor body 41 High pressure stage casing 42 High pressure stage cooling jacket 43 High pressure stage intake 44 High pressure stage outlet 50 Low pressure stage gas cooler 50a Air inlet 50b Air outlet 51 High pressure stage gas cooler 51a Air inlet 51b Air outlet 52 Oil cooler 52a Oil inlet 52b oil outlet 60 Oil filter 70 Oil pump 80 Duct 81 Blower fan R1 Low pressure stage compression chamber R2 High pressure stage compression chamber

Claims

1. A low-pressure stage compressor body having a low-pressure stage casing that defines a low-pressure stage compression chamber that compresses a sucked fluid, and a low-pressure stage cooling jacket provided in the low-pressure stage casing; a high-pressure stage casing that defines a high-pressure stage compression chamber that compresses a compressed fluid discharged from the low-pressure stage compressor body, and a high-pressure stage cooling jacket that is provided in the high-pressure stage casing; An oil cooler for cooling the oil; the high-pressure stage cooling jacket, the oil cooler, and the low-pressure stage cooling jacket are connected in series in this order; and A two-stage oil-free screw compressor.

2. The oil cooler has an oil inlet at one end and an oil outlet at the other end in a longitudinal direction, The high-pressure stage compressor body is disposed closer to the oil inlet than to the oil outlet, The two-stage oil-free screw compressor according to claim 1 , wherein the low-pressure stage compressor body is disposed closer to the oil outlet than to the oil inlet.

3. a low-pressure stage gas cooler that cools the compressed air discharged from the low-pressure stage compressor body; a high-pressure stage gas cooler that cools the compressed air discharged from the high-pressure stage compressor body; Further equipped with The low-pressure stage compressor body is disposed closer to the oil cooler than the low-pressure stage gas cooler, 3. The two-stage oil-free screw compressor according to claim 1, wherein the high-pressure stage compressor body is disposed closer to the oil cooler than the high-pressure stage gas cooler.

4. The low-pressure stage compressor body, the high-pressure stage compressor body, the oil cooler, the low-pressure stage gas cooler, and an outer box that houses the low-pressure stage gas cooler, the oil cooler, the low-pressure stage gas cooler, and the high-pressure stage gas cooler are arranged side by side in a horizontal direction, and are air-cooled heat exchangers through which cooling air passes in a vertical direction; 4. The two-stage oil-free screw compressor according to claim 3, wherein the oil cooler, the low-pressure stage gas cooler, and the high-pressure stage gas cooler are arranged directly below an exhaust port provided in an upper wall of the outer box.

5. a motor that drives the low-pressure stage compressor body and the high-pressure stage compressor body; a gear box that stores gears that transmit driving force from the motor to the low-pressure stage compressor body and the high-pressure stage compressor body; an oil filter disposed adjacent to the gearbox and configured to filter the oil exiting the low-pressure stage cooling jacket; Further equipped with 3. The two-stage oil-free screw compressor according to claim 1, wherein the gear box is disposed downstream of the oil filter in the oil flow path.

Images