JP4685474B2 - Oil-free screw air compressor - Google Patents

Description

  The present invention relates to an oil-free screw air compressor, and more particularly to an oil-free screw air compressor including a heat exchanger that cools compressed air.

  The single-stage oil-free screw air compressor has a compressor body having a pair of male and female rotors that can rotate in a non-contact and oil-free manner. Compress the air. The power required for this air compression changes to heat, and the temperature of the generated compressed air becomes very high, for example, rises to about 300 to 350 ° C. Therefore, conventionally, a configuration including a tube heat exchanger that cools compressed air discharged from a compressor body has been disclosed (see, for example, Patent Document 1).

  In the two-stage oilless screw compressor, a low-pressure compressor main body that compresses air in an oil-free state, and a high-pressure compressor main body that further compresses air compressed in the low-pressure compressor main body in an oil-free state. The temperature of the compressed air generated by the low-pressure stage compressor main body and the high-pressure stage compressor main body rises to, for example, about 160 to 250 ° C. Therefore, conventionally, a tube-type heat exchanger (intercooler) that cools the compressed air discharged from the low-pressure stage compressor body and flows out to the high-pressure stage compressor body, and cools the compressed air discharged from the high-pressure stage compressor body. The structure provided with the tube-type heat exchanger (aftercooler) to perform is disclosed (for example, refer patent document 2).

  The tube heat exchanger has a structure in which, for example, a plurality of U-shaped tubes are provided in a shell, and compressed air is flowed into the U-shaped tube and cooling water (coolant) is flowed into the shell (reversely, inside the U-shaped tube The compressed air may be allowed to flow in the shell and the compressed air may flow in the shell), and the compressed air is cooled by heat exchange between the compressed air and the cooling water. Further, the U-shaped tube in the shell has a structure with a relatively high heat-resistant temperature because it absorbs expansion and contraction due to heat and avoids the influence of thermal stress.

JP-A-3-290089 JP 2001-153080 A

However, the above prior art has room for improvement as follows.
That is, in the oil-free screw air compressor, the volume of the tube heat exchanger occupies a large proportion, and it is possible to reduce the size of the entire compressor by downsizing the heat exchanger. . However, in the tube heat exchanger, the diameter of the U-shaped tube is reduced to increase the number, the material is changed to a material having a good heat transfer coefficient, or the thickness of the U-shaped tube is decreased. Although the size can be reduced, there is a limit to the size reduction.

  An object of the present invention is to provide an oil-free screw compressor that can achieve a significant reduction in size while ensuring heat resistance.

( 1 ) In order to achieve the above object, the present invention provides a low pressure stage compressor body that compresses air in an oil-free state, and a high pressure that further compresses air compressed in the low pressure stage compressor body in an oil-free state. A main stage compressor body, a low pressure side heat exchanger that cools the compressed air of the low pressure stage compressor body and flows out to the high pressure stage compressor body, and a high pressure side heat that cools the compressed air of the high pressure stage compressor body An oil-free screw air compressor including a plate-type heat exchanger integrally configured with an exchanger, wherein the plate-type heat exchanger is a first where the compressed air of the high-pressure stage compressor body flows downward. A compressed air flow path, a second compressed air flow path through which the compressed air of the low pressure stage compressor body flows upward, and a cooling liquid that cools the compressed air of the high pressure stage compressor body flows upward. 1 cooling flow path and the first cooling flow path in series Is, coolant for cooling the compressed air of the low pressure stage compressor body and a second cooling channel flowing downward.

( 2 ) In order to achieve the above object, the present invention provides a low pressure stage compressor body that compresses air in an oilless state, and a high pressure that further compresses air compressed in the low pressure stage compressor body in an oilless state. A main stage compressor body, a low pressure side heat exchanger that cools the compressed air of the low pressure stage compressor body and flows out to the high pressure stage compressor body, and a high pressure side heat that cools the compressed air of the high pressure stage compressor body An oil-free screw air compressor including a plate-type heat exchanger integrally configured with an exchanger, wherein the plate-type heat exchanger is a first where the compressed air of the high-pressure stage compressor body flows downward. A compressed air flow path, a second compressed air flow path through which the compressed air of the low-pressure stage compressor body flows downward, and a coolant that cools the compressed air of the high-pressure stage compressor body flows upward. 1 cooling flow path and the first cooling flow path in series Is, coolant for cooling the compressed air of the low pressure stage compressor body and a second cooling channel flowing downward.

( 3 ) In the above (1) or (2) , preferably, one or both of the compressed air from the low-pressure stage compressor body and the compressed air from the high-pressure stage compressor body are primarily cooled to A tube heat exchanger that flows out to the plate heat exchanger is provided.
(4) In order to achieve the above object, the present invention provides a low pressure stage compressor body that compresses air in an oil-free state, and a high pressure that further compresses air compressed in the low pressure stage compressor body in an oil-free state. A main stage compressor body, a low pressure side heat exchanger that cools the compressed air of the low pressure stage compressor body and flows out to the high pressure stage compressor body, and a high pressure side heat that cools the compressed air of the high pressure stage compressor body An oil-free screw air compressor including a plate heat exchanger integrally configured with an exchanger, wherein the plate heat exchanger is a first compressed air through which the compressed air of the high-pressure stage compressor body flows. A flow path, a second compressed air flow path through which the compressed air of the low-pressure stage compressor body flows, a first cooling flow path through which a coolant that cools the compressed air of the high-pressure stage compressor body, and the first The low-pressure stage compressor A second cooling flow path through which a cooling liquid for cooling the compressed air flows, and the flow direction of the first compressed air flow path and the flow direction of the first cooling flow path are opposed to each other. And the flow direction of the second compressed air flow path and the flow direction of the second cooling flow path are opposed to each other, the compressed air from the low-pressure stage compressor body and the high pressure A tube-type heat exchanger is provided that primarily cools one or both of the compressed air from the main stage compressor body to the heat-resistant temperature of the plate-type heat exchanger and flows out to the plate-type heat exchanger.
(5) In order to achieve the above object, the present invention provides a low pressure stage compressor body that compresses air in an oil-free state, and a high pressure that further compresses air compressed in the low pressure stage compressor body in an oil-free state. A main stage compressor body, a low pressure side heat exchanger that cools the compressed air of the low pressure stage compressor body and flows out to the high pressure stage compressor body, and a high pressure side heat that cools the compressed air of the high pressure stage compressor body An oil-free screw air compressor including a plate heat exchanger integrally configured with an exchanger, wherein the plate heat exchanger is a first compressed air through which the compressed air of the high-pressure stage compressor body flows. A flow path, a second compressed air flow path through which the compressed air of the low-pressure stage compressor body flows, a first cooling flow path through which a coolant that cools the compressed air of the high-pressure stage compressor body, and the first The low-pressure stage compressor A second cooling flow path through which a cooling liquid for cooling the compressed air flows, and the flow direction of the second compressed air flow path and the flow direction of the second cooling flow path are parallel flows The plate is configured such that one or both of the compressed air from the low-pressure stage compressor body and the compressed air from the high-pressure stage compressor body are primarily cooled to the heat resistant temperature of the plate heat exchanger. A tube-type heat exchanger that flows out to the heat exchanger is provided.

  According to this invention, compared with the case where only the conventional tube type heat exchanger is provided, it can attain large size reduction, ensuring heat resistance.

  Embodiments of the present invention will be described below with reference to the drawings.

The first embodiment of the present invention will be described with reference to FIGS. 1 to 3. This embodiment is an embodiment in which a plate heat exchanger is provided in a two-stage oilless screw air compressor.

Figure 1 is a schematic view showing the overall structure of the oil-free screw air compressor according to the present embodiment, FIG. 2 is a schematic view showing the schematic structure of a plate heat exchanger according to this embodiment, FIG. 3, It is a perspective exploded view showing the structure of the plate type heat exchanger in this embodiment as an example. 1 and 2 , the white arrow indicates the flow of compressed air, the black arrow indicates the flow of lubricating oil, the thin arrow indicates the flow of cooling water, and the hatched arrow indicates the flow of cooling air. Yes.

  The oil-free screw compressor according to the present embodiment is a two-stage compressor, and includes an electric motor (motor) 44, a low-pressure compressor main body 46 that drives the rotational power of the electric motor 44 transmitted through a gear device 45, and a high-pressure compressor. A stage compressor body 47 and plate type heat exchangers 48 for cooling the compressed air generated by the low pressure stage compressor body 46 and the high pressure stage compressor body 47 are provided.

  The low-pressure compressor main body 46 has a pair of male rotor 49 and female rotor 50, and timing gears 51 and 52 provided at one end (left side in FIG. 3) of the male rotor 49 and female rotor 50 are provided. Meshed. Thereby, the male rotor 49 and the female rotor 50 rotate without contact and without oiling. Similarly, the high-pressure stage compressor body 47 has a pair of male rotors 53 and female rotors 54, and a timing gear 55 provided at one end (left side in FIG. 3) of the male rotors 53 and female rotors 54. 56 are engaged. Thereby, the male rotor 53 and the female rotor 54 rotate without contact and without oiling.

  The gear device 45 includes a gear casing 58 having an oil sump 57 at a lower portion and a transmission shaft 60 having a bull gear 59 that is rotatably supported by the gear casing 58. The rotation shaft of the electric motor 44 and the transmission shaft 60 are connected via a coupling 61 and the like, and pinion gears 62 and 63 provided on the other end (right side in FIG. 3) of the male rotors 51 and 53 and a bull gear 59 of the transmission shaft 60, respectively. Is engaged. Thereby, the rotational power of the electric motor 44 is transmitted to the male rotors 51 and 53 through the transmission shaft 60, the bull gear 59, and the pinion gears 62 and 63, and the male rotors 51 and 53 are rotationally driven. Note that the pinion gears 62 and 63 and the bull gear 59 are housed in a gear casing 58.

  Further, an oil pump 64 driven by an electric motor or the like is provided, and the lubricating oil sucked from the oil reservoir 57 in the gear casing 58 through the strainer 65 by the driving of the oil pump 64 is a heat exchanger for lubricating oil. (Oil cooler) 66, oil filter 67 and the like are supplied to the timing gears 51, 52, 55, 56 and bearings (not shown) of the low pressure stage compressor body 46 and the high pressure stage compressor body 47, and then the gears. It returns to the oil sump 57 in the casing 58 and circulates.

An intake filter 68 and a suction throttle valve 69 for adjusting the amount of intake air are provided on the suction side (upper side in FIG. 3) of the low-pressure compressor main body 46. Further, an air release valve 71 that releases the compressed air of the high-pressure compressor main body 47 through the silencer 70 is provided in conjunction with the suction throttle valve 69. During load operation, compression air (outside air) is sucked into the low-pressure compressor main body 46 through the intake filter 68 and the suction throttle valve 69 and compressed to a predetermined pressure, and this compressed air passes through the discharge pipe 72. The compressed air discharged to the low pressure side heat exchanger 48 a side of the plate heat exchanger 48 and cooled on the low pressure side heat exchanger 48 a side of the plate type heat exchanger 48 is connected to the high pressure stage compressor main body 47 via the outlet pipe 73. The compressed air is discharged to the high pressure side heat exchanger 48b side of the plate heat exchanger 48 through the discharge pipe 74 and cooled by the high pressure side heat exchanger 48b of the plate heat exchanger 48. The compressed air is supplied to an external device or the like (not shown) via the supply pipe 75. Further, during no-load operation, the low-pressure stage compressor body 46 and the high-pressure stage compressor body 47 are operated with the suction throttle valve 69 closed and the vent valve 71 open. The discharge pipe 74 is provided with a check valve 76, and an air discharge pipe 77 branched and connected upstream of the check valve 78 is connected to the air discharge valve 71. Further, drain pipes 78 and 79 are connected to the lower side of the outlet pipe 73 and the supply pipe 75, respectively, and drains generated during cooling of the compressed air are discharged through the drain pipes 78 and 79. .

  The plate heat exchanger 48 cools the compressed air from the low-pressure stage compressor body 46 and flows out to the high-pressure stage compressor body 48, and the compressed air from the high-pressure stage compressor body 47. The high pressure side heat exchanger 48b for cooling the air is integrally formed. Specifically, as shown in FIG. 5, for example, the plurality of stacked (8 in FIG. 5) channel plates 80 are arranged to partition the low-pressure side heat exchanger 48a and the high-pressure side heat exchanger 48b. A partition plate 81 and cover plates 82A and 82B disposed on both outer sides of the channel plate 80 are provided. The plurality of channel plates 80, the partition plate 81, and the cover plates 82A and 82B are brazed with, for example, copper ( Brazed). The channel plate 80 is made of, for example, a stainless steel thin plate and processed into a herringbone (V shape). Between the stacked channel plates 80, a compressed air flow path 83a or 83b through which compressed air flows and cooling water flow. The cooling flow paths 84a or 84b are alternately formed. The compressed air flow paths 83a and 83b and the cooling flow paths 84a and 84b have complicated flow path shapes (details are omitted), and turbulent flow is generated in the flow paths to increase the heat exchange rate (cooling efficiency).

  At the corner of the cover plate 82A constituting the low pressure stage side heat exchanger 48a, a compressed air inlet port 85a is provided on the upper side, a compressed air outlet port 85b and a cooling water inlet port 85c are provided on the lower side, and the high pressure stage side heat exchange is provided. A compressed air outlet port 86a is provided on the upper side, and a compressed air inlet port 86b and a cooling water outlet port 86c are provided on the lower side at the corners of the cover plate 82B constituting the vessel 48b. Further, through holes 87 are formed in the plurality of channel plates 80 and the partition plate 81 so as to correspond to the ports 85a to 85c and 86a to 86c, and these through holes 87 serve as the compressed air flow paths 83a or 83b or the cooling flow paths 84a. Or 84b. And the cooling water which flowed in from the cooling water inlet port 86c flows upward through the cooling flow path 84b of the high pressure side heat exchanger 48b, passes through the through hole 87 of the partition plate 81, and the cooling flow path 84a of the low pressure side heat exchanger 48a. (In other words, the cooling flow path 84b of the high-pressure side heat exchanger 48b and the cooling flow path 84a of the low-pressure side heat exchanger 48a are connected in series. ing). In the low pressure side heat exchanger 48a, the compressed air flowing in from the compressed air inlet port 85b flows upward through the compressed air passage 83a and flows out from the compressed air outlet port 85a. In the high pressure side heat exchanger 48b, the compressed air inlet The compressed air flowing in from the port 86a flows downward in the compressed air flow path 83b and flows out from the compressed air outlet port 86b. Thereby, in the low pressure side heat exchanger 48a and the high pressure side heat exchanger 48b, the compressed air and the cooling water exchange heat through the channel plate 80 to cool the compressed air.

  As can be seen from the above description, the compressed air flow path 83a and the cooling flow path 84a in the low-pressure side heat exchanger 48a and the compressed air flow path 83b and the cooling flow path 84b in the high-pressure side heat exchanger 48b are both opposed flow. It has become. For this purpose, either one of the compressed air flow paths 83a and 83b needs to be an upward flow, but in this embodiment, drain is relatively difficult to generate in the compressed air (or during no-load operation / stop). The compressed air passage 83a of the low pressure side heat exchanger 48a is directed upward.

  Further, the above-described lubricating oil heat exchanger 66, plate heat exchanger 48, cooling jacket of the low-pressure stage compressor body 46, and cooling water pipe 88 for circulating cooling water to the 47 cooling jacket of the high-pressure stage compressor body. Is provided. The cooling water pipe 88 is first branched into a piping system 88a for circulating cooling water to the lubricating oil heat exchanger 66 and a piping system 88b for circulating cooling water to the plate heat exchanger 48, and then the piping systems 88a, 88a, After the 88b merges, it is branched by a piping system 88c that distributes cooling water to the cooling jacket of the low-pressure stage compressor body 46 and a piping system 88d that distributes cooling water to the cooling jacket of the high-pressure stage compressor body 47. The piping systems 88c and 88d are configured to merge. In addition, a cooling fan 89 for inducing cooling air is provided, and the entire compressor is cooled by driving the cooling fan 89.

Next, the operation and effect of this embodiment will be described.
For example, when generating compressed air to be supplied to an external device or the like, when the electric motor 44 is driven and the rotational force of the electric motor 44 is transmitted to the male rotor 49 of the low-pressure stage compressor body 46, the male rotor 49 and the female rotor 50. Rotates without contact and without lubrication. At the same time, the rotational force of the electric motor 44 is transmitted to the male rotor 53 of the high-pressure compressor main body 47, and the male rotor 53 and the female rotor 54 are rotationally driven without contact and without lubrication. Thus, during the load operation, the compression air is sucked into the low-pressure stage compressor body 46 through the suction filter 68 and the suction throttle valve 69 and compressed to a predetermined pressure. At this time, the temperature of the compressed air generated in the low-pressure stage compressor body 46 is, for example, about 160 to 250 ° C., and repeated stress due to heat is generated when the load operation and the no-load operation are repeated. Even if the repeated stress due to temperature and heat is taken into account, the allowable temperature limit of the plate heat exchanger 48 may be acceptable. In such a case, the compressed air from the low pressure stage compressor body 46 is cooled by the low pressure side heat exchanger 48 a of the plate heat exchanger 48 and further compressed by the high pressure stage compressor body 47. At this time, the temperature of the compressed air generated in the high-pressure compressor main body 47 is also about 160 to 250 ° C., for example, and the heat resistance temperature of the plate heat exchanger 48 is considered even if the temperature of the compressed air and the repeated stress due to heat are taken into consideration. May be acceptable. In such a case, the compressed air from the high-pressure stage compressor main body 47 is cooled by the high-pressure side heat exchanger 48b of the plate heat exchanger 48 and supplied to an external device or the like via the supply pipe 75.

  In the present embodiment, a plate type in which a low-pressure side heat exchanger 48 a that cools the compressed air of the low-pressure stage compressor body 46 and a high-pressure side heat exchanger 48 b that cools the compressed air of the high-pressure stage compressor body 47 are integrally configured. A heat exchanger 48 is provided. Thereby, compared with the case where a tube type heat exchanger is each provided as a low voltage | pressure side heat exchanger and a high voltage | pressure heat exchanger like the past, significant miniaturization can be achieved.

  The plate heat exchanger 48 connects the cooling flow path 84a of the low-pressure side heat exchanger 48a and the cooling flow path 84b of the high-pressure side heat exchanger 48b in series. Thereby, compared with the case where the cooling flow paths 84a and 84b are connected in parallel, the flow rate of the cooling water can be reduced and the flow rate of the cooling water can be increased, thereby preventing the attachment of dust and scale. Moreover, since the plate-type heat exchanger 48 is configured integrally with the low-pressure side heat exchanger 48a and the high-pressure side heat exchanger 48b, piping connecting the cooling channels 48a and 48b can be reduced. In addition, since both the compressed air flow path 83a and the cooling flow path 84a in the low pressure side heat exchanger 48a and the compressed air flow path 83b and the cooling flow path 84b in the high pressure side heat exchanger 48b are opposed to each other, the plate heat exchanger The cooling performance of 48 can be improved and the size can be reduced.

The second embodiment of the present invention will be described with reference to FIG. This embodiment is an embodiment in which a tube heat exchanger and a plate heat exchanger are provided in a two-stage oilless screw air compressor.

FIG. 4 is a schematic diagram showing the entire structure of the oil-free screw air compressor according to the present embodiment. In FIG. 4, the same reference numerals are assigned to the first embodiment and like parts of the explanation is suitably omitted.

  For example, there is a case where the temperature of the compressed air generated by the high pressure stage compressor body 47 exceeds the heat resistance temperature of the plate heat exchanger 48 (specifically, when the compression rate of the high pressure stage compressor body 47 is high). Therefore, in this embodiment, the tube-type heat exchanger 90 provided in the upstream of the branch part of the discharge pipe 74 in the discharge pipe 74 is provided. The tube-type heat exchanger 90 primarily cools the compressed air from the high-pressure stage compressor main body 47, and is introduced into the high-pressure side heat exchanger 48a of the plate-type heat exchanger 48 to be secondary-cooled. Yes.

  The tube heat exchanger 90 is provided with a plurality of stainless steel U-shaped tubes 92 (for example, only two are shown in FIG. 6 for convenience) provided in the shell 91, for example, having excellent heat resistance and corrosion resistance. In order to absorb expansion and contraction due to heat, the heat resistant temperature is relatively high. Then, the compressed air from the high-pressure stage compressor body 47 flows in the U-shaped pipe 92 and the cooling water flows in the shell 91, and the compressed air is primarily cooled by heat exchange between the compressed air and the cooling water. It has become.

  Further, cooling water is supplied to the lubricating oil heat exchanger 66, the plate heat exchanger 48, the tube heat exchanger 90, the cooling jacket of the low pressure stage compressor main body 46, and the cooling jacket of the high pressure stage compressor main body 47. A circulating cooling water pipe 93 is provided. The cooling water pipe 93 includes a piping system 93a that distributes the cooling water to the lubricant heat exchanger 66, and a piping system 93b that distributes the cooling water in the order of the plate heat exchanger 48 and the tube heat exchanger 90. Are connected to the downstream side of the tube-type heat exchanger 90 in the piping system 93b, and the piping systems 93a and 93b merge to generate a high pressure. A piping system 93d for circulating cooling water is connected to the cooling jacket of the stage compressor main body 47, and then the piping systems 93c, 93d are joined.

  In the present embodiment configured as described above, the compressed air from the high-pressure compressor main body 47 is primarily cooled by the tube heat exchanger 90 having a relatively high heat resistance temperature, and the temperature of the compressed air is changed to the plate heat exchange. The temperature is lowered to the heat resistant temperature of the vessel 48 and then introduced into the plate heat exchanger 48 for secondary cooling. In this way, by using the tube heat exchanger 90 and the plate heat exchanger 48 in combination, it is possible to significantly reduce the size while ensuring heat resistance as compared with the case where only the conventional tube heat exchanger is provided. it can.

In the second embodiment, the compressed air from the high pressure stage compressor main body 47 is primarily cooled by the tube heat exchanger 90 and is secondarily cooled by the high pressure side heat exchanger 48 b of the plate heat exchanger 48. However, the present invention is not limited to this. For example, the compressed air from the low-pressure stage compressor main body 46 is primarily cooled by a tube heat exchanger, and the plate-type heat exchanger 48 has a low-pressure side heat exchanger 48a. It is good also as a structure which carries out secondary cooling, for example, compressed air from the low pressure stage compressor main body 46 and the high pressure stage compressor main body 47 is primarily cooled by each tube type heat exchanger, and is secondary by the plate type heat exchanger 48. It is good also as a structure to cool. In these cases, the same effect as described above can be obtained.

Further, in the first and second embodiments, the plate heat exchanger 48 has the compressed air flow path 83a and the cooling flow path 84a in the low pressure side heat exchanger 48a, and the compressed air flow in the high pressure side heat exchanger 48b. Although the case where the channel 83b and the cooling channel 84b are both opposed flows has been described as an example, the present invention is not limited to this. That is, for example, one or both of the compressed air flow path 83a and the cooling flow path 84a in the low pressure side heat exchanger 48a and the compressed air flow path 83b and the cooling flow path 84b in the high pressure side heat exchanger 48b may be parallel flows. Good. Such modification will be described with reference to FIG.

FIG. 5 is a schematic diagram showing a schematic structure of a plate heat exchanger according to this modification. In FIG. 5 , parts that are the same as in the above embodiment are given the same reference numerals, and descriptions thereof are omitted as appropriate.

  In the plate heat exchanger 48 ′ according to the present modification, the cooling water flowing in from the cooling water inlet port flows upward through the cooling flow path 84b of the high-pressure side heat exchanger 48b, and then the low-pressure side heat exchange, as in the above embodiment. The cooling flow path 84a of the cooler 48a flows downward and flows out of the cooling water outlet port (in other words, the cooling flow path 84b of the high pressure side heat exchanger 48b and the cooling flow path of the low pressure side heat exchanger 48a). 84a is connected in series). In the low pressure side heat exchanger 48a ′, the compressed air flowing in from the compressed air inlet port flows downward in the compressed air flow path 83a ′ and flows out from the compressed air outlet port. In the high pressure side heat exchanger 48b, the compressed air inlet port The compressed air flowing in from the port flows downward in the compressed air flow path 83b and flows out from the compressed air outlet port. That is, since the compressed air flows in the compressed air flow paths 83a ′ and 83b are both directed downward, the compressed air flow path 83a and the cooling flow path 84a in the low pressure side heat exchanger 48a ′ become parallel flows, and the high pressure side heat exchanger The compressed air flow path 83b and the cooling flow path 84b in 48b are counterflows.

  In such a modification, since the compressed air in the compressed air flow paths 83a 'and 83b flows downward, it is possible to prevent the drain generated in the compressed air from staying. Further, by making the compressed air flow path 83a and the cooling flow path 84a in the low-pressure side heat exchanger 48a 'parallel flow, the cooling capacity is reduced, but the generation of drain is suppressed, and the high pressure stage compressor main body 47 is rusted. Can be prevented from occurring. Even if the low-pressure side heat exchanger 48 'is slightly larger (in other words, the channel plate 80 constituting the low-pressure side heat exchanger 48a is slightly larger), the compressed air on the low-pressure side has a larger volume, This is preferable because the influence of loss can be reduced.

It is a mimetic diagram showing the whole structure of a 1st embodiment of an oil-free screw air compressor of the present invention. It is a schematic diagram showing the schematic structure of the plate type heat exchanger which comprises 1st Embodiment of the oil-free screw air compressor of this invention. It is a perspective exploded view showing the structure of the plate type heat exchanger which constitutes the 1st embodiment of the oil-free screw air compressor of the present invention as an example. It is a schematic diagram showing the whole structure of 2nd Embodiment of the oil-free screw air compressor of this invention. It is a schematic diagram showing the schematic structure of the plate-type heat exchanger which comprises the modification of the oilless type screw air compressor of this invention.

Explanation of symbols

4 6 Low pressure stage compressor body 47 High pressure stage compressor body 48 Plate type heat exchanger 48a Low pressure side heat exchanger 48b High pressure side heat exchanger 83a Compressed air flow path (first compressed air flow path)
83b Compressed air flow path (second compressed air flow path)
84a First cooling flow path (first cooling flow path)
84b Second cooling flow path (second cooling flow path)
90 Tube heat exchanger

Claims (5)

A low-pressure compressor body that compresses air in an oil-free state;
A high-pressure stage compressor body that further compresses the air compressed by the low-pressure stage compressor body in an oil-free state;
A low pressure side heat exchanger that cools the compressed air of the low pressure stage compressor body and flows out to the high pressure stage compressor body, and a high pressure side heat exchanger that cools the compressed air of the high pressure stage compressor body are integrally configured. An oil-free screw air compressor equipped with a plate heat exchanger,
The plate heat exchanger is
A first compressed air flow path through which the compressed air of the high-pressure stage compressor body flows downward;
A second compressed air flow path through which the compressed air of the low-pressure stage compressor body flows upward;
A first cooling flow path in which a coolant for cooling the compressed air of the high-pressure stage compressor body flows upward;
An oil-free screw comprising: a second cooling flow path that is connected in series to the first cooling flow path and in which a cooling liquid that cools the compressed air of the low-pressure stage compressor body flows downward. air compressor. A low-pressure compressor body that compresses air in an oil-free state;
A high-pressure stage compressor body that further compresses the air compressed by the low-pressure stage compressor body in an oil-free state;
A low pressure side heat exchanger that cools the compressed air of the low pressure stage compressor body and flows out to the high pressure stage compressor body, and a high pressure side heat exchanger that cools the compressed air of the high pressure stage compressor body are integrally configured. An oil-free screw air compressor equipped with a plate heat exchanger,
The plate heat exchanger is
A first compressed air flow path through which the compressed air of the high-pressure stage compressor body flows downward;
A second compressed air passage through which the compressed air of the low-pressure stage compressor body flows downward;
A first cooling flow path in which a coolant for cooling the compressed air of the high-pressure stage compressor body flows upward;
An oil-free screw comprising: a second cooling flow path that is connected in series to the first cooling flow path and in which a cooling liquid that cools the compressed air of the low-pressure stage compressor body flows downward. air compressor. The oilless screw air compressor according to claim 1 or 2 , wherein either one or both of compressed air from the low-pressure stage compressor body and compressed air from the high-pressure stage compressor body is primarily cooled, and An oil-free screw air compressor comprising a tube heat exchanger that flows out to a plate heat exchanger. A low-pressure compressor body that compresses air in an oil-free state;
A high-pressure stage compressor body that further compresses the air compressed by the low-pressure stage compressor body in an oil-free state;
  A low pressure side heat exchanger that cools the compressed air of the low pressure stage compressor body and flows out to the high pressure stage compressor body, and a high pressure side heat exchanger that cools the compressed air of the high pressure stage compressor body are integrally configured. An oil-free screw air compressor equipped with a plate heat exchanger,
The plate heat exchanger is
A first compressed air passage through which the compressed air of the high-pressure stage compressor body flows;
A second compressed air flow path through which the compressed air of the low-pressure stage compressor body flows;
A first cooling flow path through which a cooling liquid for cooling the compressed air of the high-pressure stage compressor body flows;
A second cooling channel that is connected in series to the first cooling channel and through which a coolant that cools the compressed air of the low-pressure stage compressor body flows,
The flow direction of the first compressed air flow path and the flow direction of the first cooling flow path are opposite to each other, and the flow direction of the second compressed air flow path and the second cooling flow are It is configured so that the flow direction of the road is counterflow,
Either or both of the compressed air from the low-pressure stage compressor body and the compressed air from the high-pressure stage compressor body are primarily cooled to the heat resistant temperature of the plate heat exchanger to the plate heat exchanger. An oil-free screw air compressor comprising a tube-type heat exchanger that flows out. A low-pressure compressor body that compresses air in an oil-free state;
A high-pressure stage compressor body that further compresses the air compressed by the low-pressure stage compressor body in an oil-free state;
A low pressure side heat exchanger that cools the compressed air of the low pressure stage compressor body and flows out to the high pressure stage compressor body, and a high pressure side heat exchanger that cools the compressed air of the high pressure stage compressor body are integrally configured. An oil-free screw air compressor equipped with a plate heat exchanger,
The plate heat exchanger is
A first compressed air passage through which the compressed air of the high-pressure stage compressor body flows;
A second compressed air flow path through which the compressed air of the low-pressure stage compressor body flows;
A first cooling flow path through which a cooling liquid for cooling the compressed air of the high-pressure stage compressor body flows;
A second cooling channel that is connected in series to the first cooling channel and through which a coolant that cools the compressed air of the low-pressure stage compressor body flows,
The flow direction of the second compressed air flow path and the flow direction of the second cooling flow path are configured to be parallel flows,
Either or both of the compressed air from the low-pressure stage compressor body and the compressed air from the high-pressure stage compressor body are primarily cooled to the heat resistant temperature of the plate heat exchanger to the plate heat exchanger. An oil-free screw air compressor comprising a tube-type heat exchanger that flows out.

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