JP6051271B2 - Oil-free screw compressor - Google Patents

Description

  The present invention relates to a package-type oil-free screw compressor.

  There exists a thing of patent document 1 as an example of the conventional oil-free type screw compressor. In this conventional system, cooling devices such as an air-cooled heat exchanger (intercooler, aftercooler, oil cooler, etc.) are arranged on the back of the compressor body and drive system devices (motor, gear casing, etc.). . The cooler constituting the cooling device is disposed so as to be exposed on the back surface of the package, so that low-temperature outside air is directly taken into the cooler so that the cooler can be reduced in size.

  In the prior art described in Patent Document 2, an air-cooled heat exchanger (intercooler, aftercooler, oil cooler, etc.) is disposed on one side isolated from the compressor body and drive system device in the package. ing.

JP 2002-155879 A JP-A-11-141488

  In the above-mentioned patent document 1, since a device such as a cooler constituting the cooling device is exposed on the back surface of the package and directly communicates with the device, vibration sound and pulsation sound are likely to leak out of the package from the surface of the cooler portion. was there.

  In Patent Document 2, an air-cooled heat exchanger (intercooler, aftercooler, oil cooler, etc.) is disposed on one side isolated from the compressor body and the drive system device in the package. The length of the pipe connecting the compressor body and the air-cooled heat exchanger is increased, the pressure loss is increased, and the performance of the compressor is reduced. Moreover, since the length of the pipe becomes long, it has a disadvantageous structure in terms of noise increase due to pipe vibration and cost.

  The present invention has been made in view of the above problems, and provides an oil-free screw compressor that reduces noise, secures the cooling capacity of a heat exchanger, and is compact and capable of reducing the installation area. It is an object.

In order to achieve the above object, for example, the configuration described in the claims is adopted. The present application includes a plurality of means for achieving the above object.
A low-pressure stage compressor that boosts air to a predetermined intermediate pressure;
A high-pressure compressor that boosts compressed air that has been boosted to an intermediate pressure to a predetermined discharge pressure;
A motor for driving the low-pressure stage compressor and the high-pressure stage compressor;
A low-pressure stage air-cooled heat exchanger that cools the compressed air discharged from the low-pressure stage compressor;
A high-pressure stage air-cooled heat exchanger that cools the compressed air discharged from the high-pressure stage compressor;
An air-cooled heat exchanger for lubricating oil that cools the lubricating oil supplied to the bearing and transmission of the compressor body; and
A cooling fan for passing air through the low-pressure stage air-cooled heat exchanger, the high-pressure stage air-cooled heat exchanger, and the lubricating oil air-cooled heat exchanger;
A package covering each part;
In the package, the low-pressure stage compressor, the high-pressure stage compressor, and a duct disposed above the motor,
A cooling fan disposed in the duct and supplying cooling air in the circumferential direction;
The low-pressure stage air-cooled heat exchanger, the high-pressure stage air-cooled heat exchanger, and the compressor lubricating oil air-cooled heat exchanger are disposed downstream of the cooling fan,
An exhaust duct is provided for each heat exchanger on the downstream side of the heat exchanger .

In addition, specific examples of more preferable embodiments are as follows.
(1) The high-pressure stage air-cooled heat exchanger is disposed on the upper surface of the duct, and the low-pressure stage air-cooled heat exchanger and the compressor-lubricated air cooling heat exchanger are disposed on different sides of the duct. about.
(2) The compressed air inlet and outlet of the low-pressure stage air-cooled heat exchanger are arranged vertically on the side of the duct so that they are on the low-pressure stage compressor side and the high-pressure stage compressor side, respectively.
(3) The air cooling heat exchanger for the lubricating oil of the compressor is seen below the high pressure stage air cooling heat exchanger from above the duct so as to partially overlap the high pressure stage air cooling heat exchanger. Arranged.
(4) A part of piping connecting the high-pressure stage compressor and the high-pressure stage air-cooled heat exchanger is disposed in an exhaust duct provided on the downstream side of the low-pressure stage air-cooled heat exchanger.
(5) A front-stage air-cooled heat exchanger is provided upstream of the high-pressure stage air-cooled heat exchanger, and the front-stage air-cooled type is connected to an exhaust duct connecting between the low-pressure stage air-cooled heat exchanger and the upper surface of the package. A heat exchanger was placed.
(6) A rectifying plate is provided on the upstream side of the high-pressure stage air-cooled heat exchanger.
(7) The high-temperature exhaust section downstream of the high-pressure stage air-cooled heat exchanger is blocked.
(8) The low temperature side of the exhaust duct of the low-pressure stage air-cooled heat exchanger is closed.
(9) A rectifying plate is provided inside the exhaust duct of the low-pressure stage air-cooled heat exchanger so that a large amount of cooling air flows through the front-stage air-cooled heat exchanger.
(10) A passage for bypassing the cooling air is provided from the upstream side to the downstream side of the low-pressure stage air-cooled heat exchanger.
(11) The high-temperature portion (for example, around the check valve) inside the package is passed from the upstream side of the low-pressure stage air-cooled heat exchanger, and the cooling air is bypassed downstream of the low-pressure stage air-cooled heat exchanger. Having a passage.
(12) The cooling fan is a turbo fan.
(13) A member for filling the internal space of the duct below the turbofan.
(14) A rectifying guide for introducing cooling air into the low-pressure stage air-cooled heat exchanger, the high-pressure stage air-cooled heat exchanger, and the lubricating-air air-cooled heat exchanger on the inner surface side of the duct Was established.
(15) An air inlet for cooling the motor and an air inlet for cooling each cooler are provided on the side of the package.
(16) The low-pressure stage air-cooled heat exchanger, the high-pressure stage air-cooled heat exchanger, and the lubricating air-cooled heat exchanger upstream of the cooling air, above the cooling fan, A fan motor was installed to drive the cooling fan.
(17) The low-pressure stage air-cooled heat exchanger, the high-pressure stage air-cooled heat exchanger, and the compressor-lubricated air-cooled heat exchanger are arranged in a circumferential direction and an upper surface side of the cooling fan in the duct. Be placed.
(18) The exhaust duct is connected to the upper surface of the package.

  According to the present invention, it is possible to provide an oil-free screw compressor that is compact and can reduce the installation area while reducing noise and ensuring the cooling capacity of the heat exchanger.

The unit structure figure of an oil-free screw compressor. The unit structure figure of an oil-free screw compressor. The figure which shows the structure of a non-oil supply type screw compressor, the flow of compressed air, and lubricating oil. The figure which shows the structure of a comparative example, and the flow of compressed air and lubricating oil. The figure which shows the example which has arrange | positioned the rectification | straightening guide around a cooling fan.

  As an embodiment of the present invention, a package-type oil-free screw compressor having a low-pressure stage main body and a high-pressure stage main body will be described as an example.

  1 and 2 are unit structural views of the oil-free screw compressor according to the present embodiment, and FIG. 3 shows the structure of the oil-free screw compressor according to the present embodiment and the flow of compressed air and lubricating oil. FIG. FIG. 4 is a diagram showing a comparative example, specifically, a diagram showing a structure of an oil-free screw compressor according to the comparative example, and a flow of compressed air and lubricating oil.

  In the following, the comparative example shown in FIG. 4 will be described first, and the present embodiment will be described after arranging the technical problems related to the comparative example.

  In FIG. 4, an oil-free screw compressor housed in a compressor unit case 1 (hereinafter also referred to as a unit case or a package) is a two-stage compressor, and includes a low-pressure compressor main body 2a and a high-pressure compressor. A machine main body 2b is provided. A suction throttle valve 6 is provided on the upstream side of the suction gas passage of the low-pressure compressor main body 2a. The compressor body houses a male rotor 3 and a female rotor 4 which are a pair of screw rotors in a compression chamber. The male and female rotors 3 and 4 are rotatably disposed in an oil-free and non-contact state, and a gas passage groove whose volume changes is formed on the outer periphery thereof.

  Both the compressor main bodies 2a and 2b are rotationally driven via a drive gear 7 by a compressor main body driving motor 8. The gas used for the compression is taken from the suction filter 5 from the outside at room temperature. The compressor unit case 1 is provided with a plurality of communication holes inside and outside, and these communication holes function as an air intake port or an air exhaust port. An air passage shape 19 is provided at the intake port. The air supplied to the low pressure stage compressor body 2 a and compressed here passes through a low pressure stage air-cooled heat exchanger (hereinafter referred to as an intercooler) 9 through a pipe 35 and is cooled, and then compressed through a pipe 36. It is supplied to the machine body 2b.

  The air further compressed by the high-pressure stage compressor body 2 b circulates through the pipe 34. The pipe 34 is provided with a check valve 40 and a heat exchanger, and the compressed air is disposed as necessary on the upstream side of the high-pressure stage air-cooled heat exchanger (hereinafter referred to as aftercooler) 11. After passing through a pre-stage heat exchanger (hereinafter referred to as a precooler) 10, the air is supplied to the aftercooler 11, cooled, and then discharged to the outside of the compressor unit.

  Here, if the discharge air temperature exceeds the heat resistance temperature of the intercooler 9 and the aftercooler 11 or the temperature that shortens the life due to the compression ratio of the low pressure compressor 2a or the high pressure compressor 2b, For fatigue protection, it is necessary to arrange a precooler for the intercooler 9 and / or the aftercooler 11.

  The lubricating oil filled in the gear case 12 is cooled to an appropriate temperature by an air-cooled heat exchanger (hereinafter referred to as oil cooler) 13 for compressor lubricating oil, and then the compressor bearing including the inside of the compressor main body and It is supplied to the drive gear 7 for cooling and rotational lubrication, and recovered again to the gear case 12. While the lubricating oil is necessary to be supplied to the drive gear 7 and the bearing portion of the compressor body, the present embodiment is an oil-free compressor, and the lubricating oil does not enter the air flow path. The structure is adopted. Therefore, it circulates in a path isolated from the compressed air path and is cooled by the oil cooler 13 provided in the path.

  In the comparative example shown in FIG. 4, the intercooler 9, the aftercooler 11, and the oil cooler 13 are disposed on the back surface of the compressor unit, and the cooling air from each cooler is provided by the cooling fan 14 provided upward in the package. It was set as the structure exhausted from the outside. The cooling fan 14 is rotated by a fan motor 38, and air is guided from outside the package by driving the fan motor 38, and heat is exchanged with the air to cool the compressed air and lubricating oil.

  In order to reduce the pressure loss and to guide the cooling air having the lowest possible temperature to each cooler, the cooling air passage surface is usually exposed outside the package. For this reason, there is a drawback that noise from inside the unit is likely to leak to the outside. Further, since the cooling fan 14 is exposed to the outside of the package, there is a drawback that fan noise is likely to leak to the outside. Further, as in this comparative example, when the coolers 9, 11, 13 are arranged on the back of the package, the distance between the compressor main bodies 2a, 2b and the coolers 9, 11 is increased, and the piping configuration of the discharge gas is increased. In addition to being complicated, these pipes (for example, the pipes 34, 35, and 36) are made of a stainless steel material, which makes them very expensive.

  In order to solve the above problem, a unit structure of an oil-free screw compressor having an air-cooled heat exchanger having an actual positional relationship of the present embodiment will be described with reference to FIGS. (A), (B), (C), and (D) of FIG. 1 show examples of a top view, a left side view, a front view, and a right side view of the present embodiment, respectively (also in the following description, left and right This follows this definition.) 2A and 2B are perspective views showing a unit structure of the compressor of the present embodiment, where FIG. 2A is a perspective view seen from the upper left side of the front side, and FIG. is there. FIG. 3 is a view showing the structure of the compressor of this embodiment together with the flow of compressed air and lubricating oil. Portions common to the above-described comparative example (FIG. 4) are denoted by the same reference numerals, and redundant description is omitted.

  In this embodiment, the compressor bodies 2a and 2b and the compressor driving motor 8 are arranged at the bottom of the unit case 1, and the duct 30 is provided on the upper side thereof. The intercooler 9 is provided on the left side surface of the duct 30 and the upper surface is provided on the upper surface. Has an after cooler 11 and an oil cooler 13 in the front. A cooling fan 14 is disposed inside the duct 30, and an air inlet 30 a is provided on the bottom surface of the duct 30. Exhaust ducts 31, 32, and 33 connected to the upper surface of the case 1 are provided on the downstream side of the coolers 9, 11, and 13, respectively. The cooling air is sucked into the duct 30 from the air inlet 30a by the cooling fan 14, passes through the coolers 9, 11, 13, and is exhausted upward in the case 1 through the exhaust ducts 31, 32, 33. . No cooler is disposed on the right side of the duct 30 in order to dispose a dryer (not shown) for removing moisture from the compressed air discharged from the aftercooler 11. The case 1 is provided with air inlets 1a and 1b, and the cooling air sucked from the air inlet 1a is sucked into the duct 30 from the air inlet 30a after being cooled by the motor 8, and is sucked from the air inlet 1b. The air is directly sucked into the duct 30 from the air inlet 30a.

  In this embodiment, the intercooler 9, the aftercooler 11, and the oil cooler 13 are arranged in the circumferential direction and the upper surface side of the cooling fan 14. That is, the intercooler 9 and the oil cooler 13 are arranged on the side surface of the duct 30 and exhausted upward in the case 1 through the exhaust ducts 32 and 33. In the present embodiment shown in FIG. 1, an example in which the oil cooler 13 is disposed horizontally on the side surface of the duct 30 is shown. An example in which the oil cooler 13 is arranged vertically on the side surface of the duct 30 is shown in FIG. Accordingly, the intercooler 9 and the oil cooler 13 can be configured not to be directly exposed to the outside of the case 1, and sound leakage from the inside of the unit can be suppressed to reduce the noise of the package compressor unit. it can.

  Furthermore, by disposing each cooler on the side surface and upper surface of the duct 30, the duct can be reduced in size and simplified as compared with the case where the cooler is disposed on the suction side as in the comparative example. Furthermore, since each cooler is arrange | positioned on the different surface of the duct 30, the freedom degree can be made to the size of each cooler. Further, in the comparative example, the cooling fan 14 is directly visible from the outside of the package, so that fan noise easily leaks to the outside of the package 1. However, the cooling fan 14 is connected to the coolers 9 and 11 as in this embodiment. , 13 can be prevented from leaking outside the package 1 directly from the noise generated by the cooling fan 14.

  In the present embodiment, the intercooler inlet 9a is arranged vertically on the side of the duct 30 so that the intercooler inlet 9a is on the low pressure stage compressor 2a side and the intercooler outlet 9b is on the high pressure stage compressor 2b side. The pipe 35 connecting the machine 2a and the intercooler inlet 9a and the pipe 36 connecting the intercooler outlet 9b and the high-pressure compressor 2b are significantly shortened compared to the pipe route of the comparative example. Thereby, the pressure loss of piping can be reduced significantly and performance improvement can be aimed at. Further, since the pipes 35 and 36 are made of an expensive stainless steel material, the cost can be significantly reduced by shortening the pipe length. Moreover, increase in noise due to pipe vibration can be reduced by shortening the pipe length.

  Further, in this embodiment, the oil cooler 13 is disposed laterally on the front surface of the duct 30 and is disposed so as to partially overlap the lower side of the aftercooler 11 when viewed from above the duct 30. Here, when the oil cooler 13 is disposed vertically on the front surface of the duct 30, the space in the exhaust duct 33 of the oil cooler 13 is narrowed because the space on the front side of the duct 30 in the case 1 is narrow, and the oil cooler The air temperature in the exhaust duct 33 rises due to the high-temperature exhaust of 13, and the cooling efficiency of the oil cooler 13 decreases. By adopting the structure of the present embodiment, high-temperature exhaust of the oil cooler 13 can be smoothly exhausted through the exhaust duct 33, and a decrease in the cooling efficiency of the oil cooler 13 can be prevented. Moreover, the radiation area can be reduced by overlapping the oil cooler 13 and the aftercooler 11 as in this embodiment, and the structure is advantageous for noise.

  In the present embodiment, a pipe 34 connecting the high-pressure compressor 2b and the aftercooler 11 is passed through the exhaust duct 32 of the intercooler 9 or a precooler 10 (not shown) is disposed. Since the temperature of the compressed air supplied to the precooler 10 is higher than the temperature of the compressed air supplied to the intercooler 9, the cooling air (exhaust air) that has passed through the intercooler 9 can sufficiently exchange heat. It is arranged.

  As in this embodiment, the pipe 34 or the precooler 10 between the high pressure compressor 2b and the aftercooler 11 is connected to the aftercooler 11 via the exhaust duct 32, whereby the high pressure compressor 2b and the aftercooler 11 are connected. The cooler 11 can be connected by the shortest path. Thereby, the pressure loss of piping can be reduced significantly and performance improvement can be aimed at. In addition, since the pipe 34 is made of an expensive stainless steel material, the cost can be significantly reduced by shortening the pipe length. Further, by arranging the pipe 34 or the precooler 10 in the exhaust duct 32, there is an effect that noise generated from the pipe 34 or the precooler 10 can be absorbed by the exhaust duct 32.

  Further, in this embodiment, a rectifying plate (not shown) is provided on the upstream side of the aftercooler 11 so that a large amount of cooling air flows on the low temperature side of the aftercooler 11 to improve the cooling efficiency of the aftercooler 11. Yes. Alternatively, a high temperature exhaust section downstream of the aftercooler 11 is closed so that a large amount of cooling air flows on the low temperature side of the aftercooler 11, thereby improving the cooling efficiency of the aftercooler 11.

  Further, in this embodiment, the exhaust duct 32 of the intercooler 9 is partially blocked at the low temperature exhaust side, and the low temperature exhaust is made to flow to the high temperature exhaust side, so that the exhaust temperature is averaged and the outer surface of the case 1 is heated at high temperature. To prevent heating.

  Further, in this embodiment, by providing a rectifying plate (not shown) in the exhaust duct 32 of the intercooler 9 or by restricting the outlet portion of the exhaust duct 32 as shown in the figure, a large amount of cooling air is generated by the precooler 10. The cooling efficiency of the precooler 10 is improved.

  Further, in the present embodiment, a cover 39 that communicates the opening 39 a provided in the duct 30 and the opening 39 b provided in the exhaust duct 32 is provided, and the cooling air is bypassed from the upstream side to the downstream side of the intercooler 9. Cooling that cools each cooler by lowering the temperature of the exhaust air that has become a high temperature after cooling the intercooler 9, suppressing the temperature rise of the surface of the exhaust duct 32, suppressing the air inside the case 1 from being heated It suppresses the rise in wind temperature and improves cooling efficiency. Moreover, the temperature rise in case 1 can be suppressed by arrange | positioning the high temperature part (for example, check valve 40) in case 1 inside the cover 39, and cooling with cooling air.

  A more preferred example will be described with reference to FIG. FIG. 5 shows an example in which a rectifying guide is provided around the cooling fan 14.

  As shown in FIG. 5, the cooling fan 14 is a turbo fan, and the member 42 is disposed in a dead space below the turbo fan 14 where the air does not flow, thereby improving the efficiency of the turbo fan. The inventors have confirmed that the amount of cooling air increases.

  Further, when a propeller fan is used as the cooling fan 14 as in the comparative example or the prior art, since the propeller fan can only send the cooling air in the axial direction, the coolers 9, 11, 13 have to be arranged side by side in the axial direction of the cooling fan 14, and the duct is large. On the other hand, since the turbo fan can discharge cooling air in the circumferential direction, the coolers 9, 11, and 13 can be disposed on the side surface of the duct 30, and the duct 30 can be made compact. Furthermore, by disposing the intercooler 9 and the oil cooler 13 on the side surface of the turbofan as in the present embodiment, it becomes possible to actively flow cooling air through the cooler and improve the cooling efficiency of the cooler. .

  Further, as shown in FIG. 5, members 41 a, 41 b, 41 c, 41 d, 41 e are arranged by the present inventors on the inner surface of the duct 30, and the air discharged in the circumferential direction from the turbo fan 14 is 43, 44. , 45, it is confirmed that the cooling air can efficiently flow through each of the coolers 9, 13, and 11 and the cooling efficiency of the cooler can be further improved.

  By using the members 41 and 42 shown in FIG. 5 as sound absorbing materials, suppression of sound pressure increase in 30 and high temperature air that has increased in temperature after cooling the motor 8, heat generated from the compressor main bodies 2a and 2b, Furthermore, the temperature generated by the cooling air in the duct 30 can be prevented by the heat generated from the pipes 34, 35, 36, etc., and the effect of suppressing the cooling efficiency of the coolers 9, 11, 13 can be obtained.

  Here, the turbo fan is taken as an example, but the same effect can be obtained if the fan can discharge air in the circumferential direction.

  Further, in this embodiment, an intake port 1a for cooling the motor 8 and an intake port 1b for cooling each cooler are provided on the side surface of the case 1, and the temperature rises by being sucked from the intake port 1a and cooling the motor 8. The rise in the temperature of the cooling air sucked into the duct 30 is suppressed by mixing the cooled air and the air that has not risen in temperature taken from the air inlet 1b. Naturally, ducts are provided inside the case 1 of the intake ports 1a and 1b so that sound does not leak outside the case 1.

  In this embodiment, since the fan motor 38 is arranged upstream of the coolers 9, 11, and 13, the fan motor 38 that drives the cooling fan rises in temperature due to exhaust heat from the coolers 9, 11, and 13. There is also an effect to prevent this.

  As described above, space can be saved by effective use in the compressor unit case, and a compact oil-free screw compressor with a low noise and a small installation area can be provided.

  DESCRIPTION OF SYMBOLS 1 ... Case, 1a, 1b ... Intake port, 2a ... Low pressure stage compressor body, 2b ... High pressure stage compressor body, 3 ... Male rotor, 4 ... Female rotor, 5 ... Suction filter, 6 ... Suction throttle valve, 7 ... Drive gear, 8 ... Compressor drive motor, 9 ... Low-pressure stage air-cooled heat exchanger (intercooler), 10 ... Previous stage heat exchanger (precooler), 11 ... High-pressure stage air-cooled heat exchanger (aftercooler), 12 ... Gear case, 13 ... Air-cooled heat exchanger (oil cooler) for compressor lubricating oil, 14 ... Cooling fan, 30, 31, 32 ... Duct, 34, 35, 36 ... Piping, 38 ... Fan motor, 39 ... Cover, 39a, 39b ... opening, 40 ... check valve.

Claims (19)

A low-pressure stage compressor that boosts air to a predetermined intermediate pressure;
A high-pressure compressor that boosts compressed air that has been boosted to an intermediate pressure to a predetermined discharge pressure;
A motor for driving the low-pressure stage compressor and the high-pressure stage compressor;
A low-pressure stage air-cooled heat exchanger that cools the compressed air discharged from the low-pressure stage compressor;
A high-pressure stage air-cooled heat exchanger that cools the compressed air discharged from the high-pressure stage compressor;
An air-cooled heat exchanger for compressor lubricant that cools the lubricant supplied to the bearing and transmission of the compressor body;
A cooling fan for ventilating the low-pressure stage air-cooled heat exchanger, the high-pressure stage air-cooled heat exchanger, and the air-cooled heat exchanger for compressor lubricant,
A package covering each part;
In the package, the low-pressure stage compressor, the high-pressure stage compressor, and a duct disposed above the motor,
A cooling fan disposed on the upstream side in the duct and supplying cooling air in the circumferential direction;
The low-pressure stage air-cooled heat exchanger, the high-pressure stage air-cooled heat exchanger, and the compressor lubricating oil air-cooled heat exchanger are disposed downstream of the cooling fan,
An oil-free compressor, wherein an exhaust duct is provided for each heat exchanger on the downstream side of the heat exchanger.   The oilless compressor according to claim 1, wherein the high-pressure stage air-cooled heat exchanger is disposed on an upper surface of the duct, and the low-pressure stage air-cooled heat exchanger and the compressor-lubricated air-cooled heat exchanger. Are arranged on different side surfaces of the duct.   3. The oilless compressor according to claim 2, wherein the low-pressure stage air-cooled heat exchanger includes a compressed air inlet and an outlet of the low-pressure stage air-cooled heat exchanger, and the low-pressure stage compressor side and the high-pressure stage respectively. An oilless compressor characterized in that it is arranged vertically on the side of the duct so as to be on the compressor side.   3. The oilless compressor according to claim 2, wherein the air cooling heat exchanger for the lubricating oil of the compressor is viewed from above the duct below the high pressure air cooling heat exchanger, and the high pressure air cooling is performed. An oil-free compressor characterized in that the compressor is arranged so as to partially overlap the heat exchanger.   3. The oilless compressor according to claim 2, wherein a pipe connecting the high-pressure compressor and the high-pressure air-cooling heat exchanger is connected to an exhaust duct provided downstream of the low-pressure air-cooling heat exchanger. An oil-free compressor characterized by partial arrangement.   The oil-free compressor according to claim 2, further comprising a front-stage air-cooled heat exchanger on an upstream side of the high-pressure stage air-cooled heat exchanger, between the low-pressure stage air-cooled heat exchanger and the upper surface of the package An oil-free compressor characterized in that the preceding-stage air-cooled heat exchanger is disposed in an exhaust duct connecting the two.   The oilless compressor according to claim 2, wherein a rectifying plate is provided upstream of the high-pressure stage air-cooled heat exchanger. 3. The oilless compressor according to claim 2, wherein cooling air that has passed through a high-temperature portion of the high- pressure stage air-cooled heat exchanger passes through a portion of the exhaust duct downstream of the high-pressure stage air-cooled heat exchanger. An oil-free compressor characterized in that the part to be sealed is closed. The oilless compressor according to claim 2 , wherein cooling air passing through a low-temperature part of the low-pressure stage air-cooled heat exchanger out of a part of the exhaust duct upstream of the low-pressure stage air-cooled heat exchanger. Or a portion of the exhaust duct downstream of the low-pressure stage air-cooled heat exchanger, where the cooling air passing through a low-temperature portion of the low-pressure stage air-cooled heat exchanger passes . An oilless compressor characterized by that.   6. The oilless compressor according to claim 5, wherein a rectifying plate is provided inside an exhaust duct of the low pressure stage air-cooled heat exchanger.   The oilless compressor according to claim 3, wherein a passage for bypassing cooling air is provided from the upstream side to the downstream side of the low-pressure stage air-cooled heat exchanger.   The oilless compressor according to claim 5, wherein the high-temperature portion inside the package is passed from the upstream side of the low-pressure stage air-cooled heat exchanger, and cooling air is sent to the downstream side of the low-pressure stage air-cooled heat exchanger. An oilless compressor provided with a bypass passage.   2. The oilless compressor according to claim 1, wherein the cooling fan is a turbo fan.   The oilless compressor according to claim 13, wherein a member for filling the internal space of the duct is disposed below the turbofan.   The oilless compressor according to claim 12, wherein the low-pressure stage air-cooled heat exchanger, the high-pressure stage air-cooled heat exchanger, and the compressor-lubricated air-cooled heat exchanger are disposed on the inner surface side of the duct. An oil-free compressor characterized in that a rectifying guide for introducing cooling air is provided.   2. The oilless compressor according to claim 1, wherein an air inlet for cooling the motor on a side surface of the package, the low-pressure stage air-cooled heat exchanger, the high-pressure stage air-cooled heat exchanger, and the compressor An oil-free compressor comprising: an air inlet for cooling an air-cooled heat exchanger for lubricating oil. The oilless compressor according to claim 1, wherein the low-pressure stage air-cooled heat exchanger, the high-pressure stage air-cooled heat exchanger, and the cooling air upstream of the cooling air from the compressor-lubricated air-cooled heat exchanger. Because
An oil-free compressor, wherein a fan motor for driving the cooling fan is disposed above the cooling fan.   The oil-free compressor according to claim 1, wherein the low-pressure stage air-cooled heat exchanger, the high-pressure stage air-cooled heat exchanger, and the compressor-lubricated air-cooled heat exchanger are disposed in the duct. An oilless compressor, which is disposed in a circumferential direction and an upper surface side of the cooling fan.   2. The oilless compressor according to claim 1, wherein the exhaust duct is connected to an upper surface of the package.

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