JP2015075001A - Oil-cooled air compressor and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve performance of an oil-cooled air compressor such as an amount of discharged air, energy saving performance, and prevention of thermal deterioration of lubricating oil.SOLUTION: An oil-cooled air compressor 1 comprises a compressor body 2 and an oil separating/recovering device 3. An oil reservoir of the oil separating/recovering device 3 is connected to a suction port 2c of the compressor body 2 via an oil supply passage 7. The compressor body 2 is provided with a cooling water supply passage 31 that supplies cooling water. The cooling water is supplied to the compressor body 2 to cool sucked air so that a temperature of compressed air discharged from a discharge port 2d of the compressor body 2 is equal to or less than a dew point.

Description

  The present invention relates to an oil-cooled air compressor and a control method thereof.

  In the oil-cooled air compressor, lubricating oil is mixed in the air compressed by the compressor body in order to lubricate the compressor body. The compressed air discharged from the compressor main body is sent to the oil separator / collector and separated into compressed air and lubricating oil. In an oil-cooled air compressor, the temperature of oil injection to the rotor chamber is set to 45 ° C to 55 ° C, and the discharge temperature is reduced to the temperature at which drain water is deposited (the temperature below the dew point) in the oil separator / collector. It is known as a means for improving performance by increasing the amount of air. However, since the drain water deposited in the oil separator / recovery device causes deterioration of the lubricating oil, an operation of draining the drain water accumulated in the oil separation / recovery device (drain removing operation) is required.

  In the current oil-cooled air compressor, drain water accumulation in the oil separation and recovery unit is intentionally adjusted to a temperature above the dew point (for example, about 80 ° C.) by evaporating the water. Is preventing. For example, in Patent Document 1, by supplying lubricating oil not through an oil cooler to the discharge port side of the rotor chamber of the compressor main body, the discharge temperature is set to a temperature at which the inside of the oil separation and recovery device is equal to or higher than the dew point. Is disclosed. Further, in Patent Document 2, the temperature of the lubricating oil supplied to the compressor body is adjusted by controlling the flow rate ratio of the lubricating oil passing through the oil cooler to the lubricating oil without going through the oil cooler, and thereby the oil separator / recoverer It is disclosed that the discharge temperature is adjusted so that the inside becomes the dew point or higher.

  However, Patent Document 1 does not take into consideration that the discharge temperature is lower than the temperature at which drain water is precipitated in the oil separation and recovery device. Moreover, in patent document 2, it is necessary to maintain the temperature of an oil separation collection | recovery device at high temperature, and it is difficult to reduce discharge temperature. Furthermore, in Patent Document 2, the lubricating oil is kept at a high temperature during the operation of the oil-cooled air compressor, which leads to deterioration of the lubricating oil. As described above, conventional oil-cooled air compressors including those disclosed in Patent Documents 1 and 2 have room for further performance improvement.

Japanese Unexamined Patent Publication No. 7-35067 JP 2012-112268 A

  An object of the present invention is to improve the performance of an oil-cooled air compressor, such as the amount of discharged air, energy saving, and prevention of temperature deterioration of lubricating oil.

  The present invention includes an oil-cooled compressor main body that compresses and discharges sucked air, an oil separation and recovery device that separates and recovers lubricating oil from the compressed air discharged from the compressor main body, and the oil separation An oil supply passage that connects the recovery device and the suction side of the compressor body, and a cooling water supply passage that supplies cooling water that cools the air so that the air is below the dew point in the compressor body An oil-cooled air compressor is provided. Thereby, the temperature of the compressed air discharged from the compressor body (hereinafter sometimes referred to as a discharge temperature) can be set to a dew point or lower.

  By setting the discharge temperature of the compressor main body to a dew point or lower, it is possible to improve performance by increasing the amount of discharged air, and energy saving is improved. Further, since the discharge temperature is lower than the dew point and not high, the temperature deterioration of the lubricating oil can be prevented.

  It is preferable that the cooling water supply position is at least one of a suction portion and a compression tooth groove of the compressor body.

  At least one of the intake air and the compressed air can be cooled, and the performance can be improved by increasing the discharge air amount.

  It is preferable to provide an oil-water separator that separates the cooling water and moisture generated in the compressor body during air compression from the lubricating oil outside the compressor body.

  By providing an oil / water separator, it is possible to reliably prevent moisture in the compressed air generated when the discharge temperature is below the dew point from being mixed with the lubricating oil, and to reduce the quality of the lubricating oil due to the mixing of moisture in the lubricating oil. Can be avoided.

  A drain water supply passage that is provided in the oil / water separator and connects the drain discharge portion for discharging drain water, the drain discharge portion and the suction side of the compressor body, and supplies the drain water as the cooling water. It is preferable to comprise.

  It is possible to eliminate the necessity of removing the drain water by removing the oil from the drain water having the possibility that the oil remains.

  It is preferable that a drain water solenoid valve is provided in the drain water supply flow path, and the drain water solenoid valve is opened and closed by a timer.

  After the set time by the timer elapses, the water separated and stored by the oil / water separator can be discharged from the oil / water separator.

  A cooling water solenoid valve provided in the cooling water supply flow path, a discharge air temperature sensor for directly or indirectly measuring the temperature of the compressed air discharged from the compressor body, and the discharge air temperature sensor. And a controller for controlling the opening and closing of the cooling water solenoid valve based on the measured temperature, wherein the controller has a temperature measured by the discharge air temperature sensor higher than a preset first supply start temperature. The cooling water solenoid valve is opened, and if it is determined that the temperature measured by the discharge air temperature sensor is equal to or lower than the first supply stop temperature set in advance, the cooling water solenoid valve is opened. It is preferable to close the valve.

  The temperature of the compressed air discharged from the compressor body can be maintained so as to be equal to or lower than the first supply stop temperature.

  It is preferable to start supplying the cooling water through the cooling water supply channel after a predetermined time has elapsed after the oil-cooled air compressor is started.

  In the apparatus, it is possible to avoid the occurrence of freezing trouble due to the supply of cooling water.

  A solenoid valve for cooling water provided in the cooling water supply channel, an intake air temperature sensor for measuring the temperature of the intake air of the compressor body, and the temperature of the compressed air discharged from the compressor body directly or A temperature detection sensor comprising any one of a discharge air temperature sensor for indirectly measuring, an oil separator / collector temperature sensor for measuring a temperature in the oil separator / collector, and an ambient temperature sensor for measuring an ambient temperature; A controller for controlling opening and closing of the solenoid valve for cooling water based on the temperature measured by the temperature detection sensor, wherein the controller starts the second supply in which the temperature measured by the temperature detection sensor is set in advance. If it is determined that the temperature is higher than the temperature, the solenoid valve for cooling water is opened, and the temperature measured by the temperature detection sensor is determined to be equal to or lower than a preset second supply stop temperature. , It is preferable to close the solenoid valve for the cooling water.

  When the measured temperature of the temperature detection sensor is equal to or lower than the second supply stop temperature, the supply of cooling water can be stopped, and the occurrence of freezing trouble due to the supply of cooling water in the compressor body can be avoided. .

  It is preferable that a heater is provided in the compressor body or the cooling water supply flow path, and the heater is operated when the temperature measured by the temperature detection sensor is equal to or lower than the second supply stop temperature.

  When the temperature measured by the temperature detection sensor is equal to or lower than the second supply stop temperature, the cooling water can be heated by operating the heater. Thereby, it can avoid that the trouble of freezing arises by supply of cooling water in an apparatus.

  The specific gravity of the lubricating oil is preferably 0.95 or less.

  By using a lubricating oil having a specific gravity lower than that of water, that is, a lubricating oil having a specific gravity difference from water, water can be more easily and reliably separated from the lubricating oil in the oil / water separator.

  The lubricating oil is preferably hydrophobic.

  By using hydrophobic lubricating oil, water can be more easily and reliably separated from the lubricating oil in the oil / water separator.

  The present invention includes an oil-cooled compressor main body that compresses and discharges sucked air, an oil separation and recovery device that separates and recovers lubricating oil from the compressed air discharged from the compressor main body, and the oil separation An oil-cooled air compressor control method comprising an oil supply passage connecting a recovery device and a suction side of the compressor body, and a cooling water supply passage for supplying cooling water for cooling the air, Cooling water is supplied by the cooling water supply channel so that the air is below the dew point in the compressor body or the discharge temperature, which is the temperature of the compressed air discharged from the compressor body, is below the dew point. A method for controlling an oil-cooled air compressor is provided that cools the air by supplying air.

  By setting the discharge temperature of the compressor main body to a dew point or lower, it is possible to improve performance by increasing the amount of discharged air, and energy saving is improved. Further, since the discharge temperature is lower than the dew point and not high, it is possible to prevent the temperature deterioration of the lubricating oil, that is, the quality deterioration.

The schematic diagram which shows the whole structure of the oil-cooled air compressor which concerns on 1st Embodiment of this invention. The schematic diagram which shows the whole structure of the oil-cooled air compressor which concerns on 2nd Embodiment of this invention. The schematic diagram which shows the whole structure of the oil-cooled air compressor which concerns on 3rd Embodiment of this invention. The schematic diagram which shows the whole structure of the oil-cooled air compressor which concerns on 4th Embodiment of this invention. The schematic diagram which shows the whole structure of the oil-cooled air compressor which concerns on 5th Embodiment of this invention. The schematic diagram which shows the whole structure of the oil-cooled air compressor which concerns on 6th Embodiment of this invention. The schematic diagram which shows the whole structure of the oil-cooled air compressor which concerns on 7th Embodiment of this invention. The schematic diagram which shows the whole structure of the oil-cooled air compressor which concerns on 8th Embodiment of this invention. The schematic diagram which shows the whole structure of the oil-cooled air compressor which concerns on 9th Embodiment of this invention. The schematic diagram which shows the whole structure of the oil-cooled air compressor which concerns on 10th Embodiment of this invention. The typical fragmentary sectional view of a compressor main body.

(First embodiment)
FIG. 1 shows an oil-cooled air compressor 1 according to a first embodiment of the present invention. The oil-cooled air compressor 1 includes a compressor body 2 that is an oil-cooled screw compressor, and an oil separation and recovery device 3.

  Referring also to FIG. 11, the compressor main body 2 includes a pair of male and female rotors 2b, 2b (rotated and driven by a driving device not shown) housed in the rotor chamber 2a. In addition, a suction port (suction part) 2c and a discharge port 2d communicating with the rotor chamber 2a are provided. The compressor main body 2 is provided with a cooling water supply passage 31 for supplying cooling water for cooling the air below the dew point. The end of the cooling water supply channel 31 is connected to the cooling water supply port 32. In the present embodiment, the cooling water is tap water. In FIG. 11, the connection position with the compressor main body 2 of the cooling water supply flow path 31, that is, the water supply position is conceptually indicated by the symbol P 0. The cooling water supply passage 31 is provided with a solenoid valve (cooling water solenoid valve) 33 controlled by a controller (not shown).

  A discharge port 2 d of the compressor body 2 is connected to the oil separation / recovery device 3 through a discharge flow path 6.

  An oil sump at the lower part of the oil separator / recovery unit 3 is connected to a suction port 2 c of the compressor body 2 via an oil supply passage 7. In FIG. 11, the connection position of the suction port 2 c of the oil supply passage 7, that is, the oil supply position is conceptually indicated by the symbol P <b> 2. In the present embodiment, the oil cooler 4 is provided in the oil supply passage 7.

  In the rotor chamber 2a of the compressor body 2, the space formed by the tooth spaces of the rotors 2b and 2b and the inner wall of the rotor chamber 2a is reduced as the rotor 2b and 2b rotate, and the volume is reduced thereby. The air sucked from the port 2c is compressed and discharged from the discharge port 2d. The compressed air discharged from the discharge port 2 d flows into the oil separation / recovery device 3 through the discharge flow path 6. In the oil separator / collector 3, the lubricating oil is separated from the compressed air and temporarily stored in a lower oil sump. The compressed air from which the lubricating oil has been separated is sent from the outlet 3a of the oil separator / recoverer 3 to the downstream side (not shown).

  The lubricating oil stored in the oil sump of the oil separator / recovery unit 3 passes through the oil supply passage 7 by the differential pressure between the oil separation / recovery unit 3 and the compressor body 2 (suction port 2c), and the compressor body 2 (FIG. 11). To the refueling position P2). In the present embodiment, the lubricating oil flowing to the compressor body 2 through the oil supply passage 7 is precooled when passing through the oil cooler 4.

  On the other hand, in the oil-cooled air compressor 1, cooling water for cooling the air is supplied by the cooling water supply passage 31 so that the air sucked from the suction port 2 c is below the dew point in the compressor body 2. Is done. In other words, in the oil-cooled air compressor 1, the temperature (discharge temperature) of the compressed air discharged from the discharge port 2 d of the compressor body 2 is less than the dew point (water condensation temperature) by the cooling water supply flow path 31. Thus, cooling water for cooling the air sucked from the suction port 2c is supplied. The air sucked from the suction port 2c becomes the dew point or less in the compressor body 2, and the moisture in the compressed air is condensed (condensed) in the compressor body 2, thereby improving the performance by increasing the amount of discharged air. Energy saving is improved. Further, since the discharge temperature is lower than the dew point and not high, the temperature deterioration of the lubricating oil can be prevented.

  Further, since the compressed air is already below the dew point when it is discharged from the discharge port 2d of the compressor body 2, the compressed air cooler or the compressed air is placed at a position downstream of the compressed air flow. When installing a dryer for removing moisture, the cooling capacity can be reduced. Further, by providing the cooling water supply flow path 31, the lubricating oil can be cooled in the compressor body by the cooling water, and the power consumption of the oil cooler 4 can be suppressed.

(Second Embodiment)
FIG. 2 shows an oil-cooled air compressor 1 according to the second embodiment of the present invention. The cooling water supply channel 31 supplies cooling water that cools the air so that the air sucked from the suction port 2 c is below the dew point in the compressor body 2. In other words, the cooling water supply channel 31 supplies the cooling water that cools the air sucked from the suction port 2c so that the discharge temperature of the compressor body 2 is equal to or lower than the dew point. The configuration of the present embodiment is the same as the configuration of the first embodiment except that an oil / water separator 5 for separating moisture from the lubricating oil is provided in the oil supply passage 7 instead of the oil cooler 4. .

  By setting the discharge temperature to be equal to or lower than the dew point, condensed air is contained in the compressed air discharged from the discharge port 2d of the compressor body 2. The compressed air contains the cooling water supplied by the cooling water supply channel 31. Moisture mixed in the lubricating oil causes deterioration of the lubricating oil. However, by providing the oil / water separator 5 to separate the lubricating oil and the water, it is possible to prevent the deterioration of the lubricating oil due to the mixed water.

  In the oil-cooled air compressor 1 of the present embodiment, the discharge temperature of the compressor main body 2 is reduced to the dew point while the discharge temperature of the compressor main body 2 is set to the dew point or less to improve performance and prevent temperature degradation of the lubricating oil. By providing the oil / water separator 5, water mixing in the lubricating oil due to the following and deterioration of the lubricating oil resulting therefrom are prevented.

  In order to more easily and reliably separate water from the lubricating oil in the oil / water separator 5, the lubricating oil preferably has hydrophobicity. Further, by using a lubricating oil having a specific gravity lower than that of water, that is, a lubricating oil having a specific gravity difference from that of water, the oil / water separator 5 can more easily and reliably separate water from the lubricating oil. For example, the specific gravity of the lubricating oil is preferably 0.95 or less.

(Third embodiment)
FIG. 3 shows an oil-cooled air compressor 1 according to the third embodiment of the present invention. The cooling water supply channel 31 supplies cooling water that cools the air so that the air sucked from the suction port 2 c is below the dew point in the compressor body 2. In other words, the cooling water supply channel 31 supplies the cooling water that cools the air sucked from the suction port 2c so that the discharge temperature of the compressor body 2 is equal to or lower than the dew point. The configuration of the present embodiment is the same as the configuration of the first embodiment except that the oil cooler 4 is not provided in the oil supply passage 7.

  The air sucked from the suction port 2c becomes the dew point or less in the compressor body 2, and the moisture in the compressed air is condensed (condensed) in the compressor body 2, thereby improving the performance by increasing the amount of discharged air. Energy saving is improved. Further, since the discharge temperature is lower than the dew point and not high, the temperature deterioration of the lubricating oil can be prevented.

(Fourth embodiment)
FIG. 4 shows an oil-cooled air compressor 1 according to the fourth embodiment of the present invention. The cooling water supply channel 31 supplies cooling water that cools the air so that the air sucked from the suction port 2 c is below the dew point in the compressor body 2. In other words, the cooling water supply channel 31 supplies the cooling water that cools the air sucked from the suction port 2c so that the discharge temperature of the compressor body 2 is equal to or lower than the dew point. The configuration of this embodiment is the same as the configuration of the first embodiment except that the oil / water separator 5 is provided in the discharge flow path 6. In the present embodiment, since the oil / water separator 5 is provided in the discharge flow path 6, it is possible to prevent moisture from condensing in the oil separator / collector 3 and accumulating as drain water in the oil reservoir.

  Other operations of the fourth embodiment are the same as those of the first embodiment.

(Fifth embodiment)
FIG. 5 shows an oil-cooled air compressor 1 according to the fifth embodiment of the present invention. The cooling water supply channel 31 supplies cooling water that cools the air so that the air sucked from the suction port 2 c is below the dew point in the compressor body 2. In other words, the cooling water supply channel 31 supplies the cooling water that cools the air sucked from the suction port 2c so that the discharge temperature of the compressor body 2 is equal to or lower than the dew point. The configuration of the present embodiment is the same as the configuration of the first embodiment except that the oil / water separator 5 is provided in the oil separator / recovery unit 3. By providing the oil / water separation device 5 in the oil separation / recovery device 3, compared to the case where the oil separation / recovery device 3 and the oil / water separation device 5 are provided separately, the installation projected area of the oil-cooled air compressor 1 is reduced. Increase can be avoided.

  Other operations of the fifth embodiment are the same as those of the first embodiment.

(Sixth embodiment)
FIG. 6 shows an oil-cooled air compressor 1 according to a sixth embodiment of the present invention. The cooling water supply channel 31 supplies cooling water that cools the air so that the air sucked from the suction port 2 c is below the dew point in the compressor body 2. In other words, the cooling water supply channel 31 supplies the cooling water that cools the air sucked from the suction port 2c so that the discharge temperature of the compressor body 2 is equal to or lower than the dew point.

  In the present embodiment, a bypass flow path 12 that branches from the upstream side of the oil cooler 4 of the oil supply flow path 7 and merges with the oil supply flow path 7 on the downstream side of the oil cooler 4 is provided. Due to the differential pressure between the oil separator / collector 3 and the compressor body 2, the lubricating oil flows through the bypass flow path 12 and bypasses the oil cooler 4. That is, the lubricating oil can be allowed to flow into the oil / water separator 5 without using a pump. By arranging the oil cooler 4 and the oil / water separator 5 in parallel in different flow paths, the flow resistance of the lubricating oil can be reduced as a whole flow path from the oil separator / collector 3 to the compressor body 2.

  Other configurations and operations of the sixth embodiment are the same as those of the first embodiment.

(Seventh embodiment)
FIG. 7 shows an oil-cooled air compressor 1 according to a seventh embodiment of the present invention. The cooling water supply channel 31 supplies cooling water that cools the air so that the air sucked from the suction port 2 c is below the dew point in the compressor body 2. In other words, the cooling water supply channel 31 supplies the cooling water that cools the air sucked from the suction port 2c so that the discharge temperature of the compressor body 2 is equal to or lower than the dew point.

  In the present embodiment, a drain discharge portion 5 a for discharging drain water is provided at the bottom of the oil / water separator 5. The drain discharge part 5 a of the oil / water separator 5 is connected to the suction port 2 c of the compressor body 2 via the drain water supply flow path 34. In FIG. 11, the connection position of the suction port 2 c of the drain water supply flow path 34, that is, the water supply position is conceptually indicated by the symbol P <b> 1. The drain water supply channel 34 removes the oil from the drain water having the possibility of remaining oil by returning the drain water of the oil / water separator 5 as cooling water to the suction port 2c of the compressor main body 2, thereby removing the drain water. Can eliminate the need to discharge

  Other configurations and operations of the seventh embodiment are the same as those of the sixth embodiment.

  As shown by a two-dot chain line in FIGS. 2, 4, and 5, the second, fourth, and fifth embodiments are also provided with a drain discharge portion 5 a at the bottom of the oil / water separator 5, as in the present embodiment. You may provide the drain water supply flow path 34 which connects 5a and the suction inlet 2c of the compressor main body 2. FIG.

(Eighth embodiment)
FIG. 8 shows an oil-cooled air compressor 1 according to the eighth embodiment of the present invention. The cooling water supply channel 31 supplies cooling water that cools the air so that the air sucked from the suction port 2 c is below the dew point in the compressor body 2. In other words, the cooling water supply channel 31 supplies the cooling water that cools the air sucked from the suction port 2c so that the discharge temperature of the compressor body 2 is equal to or lower than the dew point. The drain water supply flow path 34 is provided with a solenoid valve (drain water solenoid valve) 35. The electromagnetic valve 35 is provided with a timer 36 connected to the controller 19. After the set time by the timer 36 elapses, the water separated and stored by the oil / water separator 5 can be discharged from the oil / water separator 5.

  Other configurations and operations of the eighth embodiment are the same as those of the seventh embodiment.

(Ninth embodiment)
FIG. 9 shows an oil-cooled air compressor 1 according to the ninth embodiment of the present invention.

  A discharge air temperature sensor 18 that directly or indirectly measures the discharge temperature that is the temperature of the compressed air discharged from the discharge port 2d of the compressor body 2 is provided. In the present embodiment, the discharge air temperature sensor 18 is provided in the oil separation / recovery unit 3 and measures the discharge temperature indirectly by measuring the temperature of the oil separation / recovery unit 3. However, the discharge air temperature sensor 18 may be disposed at or near the discharge port 2d to directly measure the discharge temperature. Further, the discharge temperature may be indirectly measured by disposing the discharge air temperature sensor 18 at a place other than the oil separator / collector 3.

  The controller 19 adjusts the cooling water supply flow path 31 according to the detected temperature of the discharge air temperature sensor 18 so that the discharge temperature, which is the temperature of the compressed air discharged from the discharge port 2d of the compressor main body 2, is equal to or lower than the dew point. The electromagnetic valve 33 is controlled. Specifically, if the controller 19 determines that the temperature is higher than a preset first supply start temperature (set temperature equal to or lower than the dew point temperature) based on the temperature measured by the discharge air temperature sensor 18, the solenoid valve 33. Is opened and cooling water is supplied to cool the air sucked from the suction port 2c. On the other hand, if the controller 19 determines that the temperature is equal to or lower than the first supply stop temperature lower than the first supply start temperature set in advance based on the temperature measured by the discharge air temperature sensor 18, the controller 19 The valve is closed and the supply of the cooling water is stopped, that is, the cooling of the air sucked from the suction port 2c is stopped. The temperature of the compressed air discharged from the compressor body 2 can be maintained so as to be equal to or lower than the first supply stop temperature.

  Other configurations and operations of the ninth embodiment are the same as those of the eighth embodiment.

(10th Embodiment)
FIG. 10 shows an oil-cooled air compressor 1 according to a tenth embodiment of the present invention.

  The oil separator / collector 3 is provided with a discharge air temperature sensor 18 as a temperature detection sensor. A heater 37 is provided in the cooling water supply passage 31 between the electromagnetic valve 33 and the compressor body 2.

  If the controller 19 determines that the temperature is higher than a preset second supply start temperature (a set temperature higher than the freezing temperature) based on the temperature measured by the discharge air temperature sensor 18, the controller 19 The valve 33 is opened and cooling water is supplied to cool the air sucked from the suction port 2c. On the other hand, if the controller 19 determines that the temperature is equal to or lower than the preset second supply stop temperature based on the temperature measured by the discharge air temperature sensor 18, the controller 19 closes the solenoid valve 33 and supplies the cooling water. Stop. Thereafter, the controller 19 operates the heater 37. When the measured temperature of the discharge air temperature sensor 18 is equal to or lower than the second supply stop temperature (set temperature equal to or lower than the freezing temperature), the supply of cooling water can be stopped, and the cooling water is It is possible to avoid the problem of freezing due to the supply. Further, since the cooling water can be heated by operating the heater 37, it is possible to avoid the occurrence of freezing trouble due to the supply of the cooling water in the apparatus. The temperature detection sensor includes a suction air temperature sensor 38 that measures the temperature of the suction air of the compressor main body 2 and a discharge temperature that measures the discharge temperature provided in the discharge flow path 6, as shown by a two-dot chain line in FIG. 10. Any one of the flow path temperature sensor 39 and the ambient temperature sensor 40 that measures the ambient temperature may be used.

  In addition, although description is abbreviate | omitted in description of the above-mentioned embodiment, especially about the method of calculating | requiring the dew point required for judgment whether the temperature of the compressed air discharged from the compressor main body 2 is more than a dew point. It is not limited. For example, the pressure measurement value and the temperature measurement value of the compressed air immediately before or immediately after the discharge may be obtained. The pressure measurement value of the compressed air in the oil separation and recovery unit 3 and the temperature of the compressed air or oil in the oil separation and recovery unit 3 You may obtain | require from a measured value. In the latter case, when the pressure loss from the discharge port 2d to the oil separation / recovery unit 3 is not substantially negligible, the pressure value necessary for calculating the dew point takes the pressure loss into consideration in the pressure measurement value in the oil separation / recovery unit 3. Can be obtained. In the latter case, the temperature required for calculating the dew point is determined by measuring the temperature of the compressed air or oil in the oil separation / recovery unit 3 after being discharged based on the temperature drop that occurs from the discharge port 2d to the oil separation / recovery unit 3. The amount of heat released can be determined in consideration of the amount of heat released from the pipes and oil separator / collector constituting the discharge flow path.

  Moreover, although description is abbreviate | omitted in description of the above-mentioned embodiment, when connecting piping to the bottom face of the oil separation collection | recovery device 3, the bottom part of the oil separation collection | recovery device 3 is formed in spherical shape, and piping is used for the lowest part. It is desirable to connect. By doing so, oil with much water contamination can be extracted.

  Moreover, in the schematic diagram explaining the above-mentioned embodiment, illustration is abbreviate | omitted in the well-known structure like the bearing which supports rotor 2b, 2b and the bearing oil supply line which supplies oil with respect to the bearing.

  The oil-cooled air compressor 1 of the present invention is not limited to the configuration of the above embodiment, and various modifications can be made.

  In the first to tenth embodiments, instead of the configuration in which the cooling water supply flow path 31 is connected to the position indicated by the symbol P0 in FIG. 11, the symbol P2 ′ (to the rotors 2b and 2b in the rotor chamber 2a in the compression process). Water supply position), P3 (water supply position to the space immediately after the suction port 2c of the rotor chamber 2a (immediately after closing)), P4 (space immediately before the discharge port 2d of the rotor chamber 2a (immediately before discharge)) You may make it the structure connected to at least 1 of the position shown by (water supply position). Further, the cooling water supply channel 31 may be connected to the position indicated by the symbol P0 and at least one of the positions indicated by the symbols P2 ', P3, and P4. In addition, the position shown with the code | symbol P0 is a supply position to the suction inlet 2c, and the position shown with code | symbol P2 ', P3, and P4 is a supply position to the tooth gap of the rotors 2b and 2b.

  In the first to tenth embodiments, the cooling water supply channel 31 may start supplying cooling water after the oil-cooled air compressor 1 is started and a preset time has elapsed. In the apparatus, it is possible to avoid the occurrence of freezing trouble due to the supply of cooling water.

  The heater 37 may be provided in the compressor main body 2 as shown by a two-dot chain line in FIG. 10 without being provided in the cooling water supply flow path 31. Further, the heater 37 may be provided in both the cooling water supply channel 31 and the compressor body 2.

  In the sixth to tenth embodiments, an electromagnetic valve for temporarily blocking the flow of the lubricating oil may be provided on the upstream side or the downstream side of the oil / water separator 5 of the bypass flow path 12. Thereby, the quantity of the lubricating oil preliminarily cooled in the oil cooler 4 can be increased or decreased. Moreover, you may provide the solenoid valve which interrupts | blocks the flow of lubricating oil temporarily in both the upstream and downstream of the oil-water separator 5 of the bypass flow path 12. Thereby, the oil-water separator 5 can be inspected while continuing the operation of the compressor.

  The cooling water demonstrated above contains what added the additive etc. to water, and the thing which has water as a main component.

DESCRIPTION OF SYMBOLS 1 Oil-cooled air compressor 2 Compressor main body 2a Rotor chamber 2b Rotor 2c Suction port (suction part)
2d Discharge port 3 Oil separator / collector 3a Outlet 4 Oil cooler 5 Oil / water separator 5a Drain discharge part 6 Discharge flow path 7 Oil supply flow path 12 Bypass flow path 18 Discharge air temperature sensor 19 Controller 31 Cooling water supply flow path 32 Cooling water Supply port 33 Solenoid valve (solenoid valve for cooling water)
34 Drain water supply flow path 35 Solenoid valve (solenoid valve for drain water)
36 Timer 37 Heater 38 Suction air temperature sensor 39 Discharge flow path temperature sensor 40 Ambient temperature sensor

Claims (13)

An oil-cooled compressor body that compresses and discharges the sucked air; and
An oil separation and recovery device for separating and recovering the lubricating oil from the compressed air discharged from the compressor body;
An oil supply passage connecting the oil separator and the suction side of the compressor body;
An oil-cooled air compressor, comprising: a cooling water supply passage that supplies cooling water that cools the air so that the air has a dew point or less in the compressor body.   2. The oil-cooled air compressor according to claim 1, wherein a supply position of the cooling water is at least one of a suction portion and a compression tooth groove of the compressor body.   The oil-cooled air according to claim 1 or 2, further comprising an oil-water separator that separates the cooling water and moisture generated in the compressor body during air compression from the lubricating oil outside the compressor body. Compressor. A drain discharger provided in the oil / water separator for discharging drain water;
The oil-cooled air compressor according to claim 3, further comprising: a drain water supply channel that connects the drain discharge unit and a suction side of the compressor body and supplies the drain water as the cooling water. A drain water solenoid valve is provided in the drain water supply channel,
The oil-cooled air compressor according to claim 4, wherein the drain water solenoid valve is opened and closed by a timer. A solenoid valve for cooling water provided in the cooling water supply flow path;
A discharge air temperature sensor for directly or indirectly measuring the temperature of the compressed air discharged from the compressor body;
A controller that controls opening and closing of the electromagnetic valve for cooling water based on the temperature measured by the discharge air temperature sensor,
If the controller determines that the temperature measured by the discharge air temperature sensor is higher than a preset first supply start temperature, the controller opens the cooling water solenoid valve and measures the temperature by the discharge air temperature sensor. The oil-cooled air compressor according to any one of claims 1 to 5, wherein when the determined temperature is equal to or lower than a preset first supply stop temperature, the cooling water solenoid valve is closed. .   The oil-cooled air according to any one of claims 1 to 6, wherein the cooling water supply passage is started after the oil-cooled air compressor is started and a preset time has elapsed. Compressor. A solenoid valve for cooling water provided in the cooling water supply flow path;
An intake air temperature sensor for measuring the temperature of the intake air of the compressor body, a discharge air temperature sensor for directly or indirectly measuring the temperature of the compressed air discharged from the compressor body, A temperature detection sensor comprising any one of an oil separator / collector temperature sensor for measuring temperature and an ambient temperature sensor for measuring ambient temperature;
A controller for controlling opening and closing of the cooling water solenoid valve based on the temperature measured by the temperature detection sensor,
If the controller determines that the temperature measured by the temperature detection sensor is higher than a preset second supply start temperature, the controller opens the cooling water solenoid valve and measures the temperature by the temperature detection sensor. The oil-cooled air compressor according to claim 1, wherein if the temperature is determined to be equal to or lower than a preset second supply stop temperature, the cooling water solenoid valve is closed. A heater is provided in the compressor body or the cooling water supply flow path,
The oil-cooled air compressor according to claim 8, wherein the heater is operated when a temperature measured by the temperature detection sensor is equal to or lower than the second supply stop temperature.   The oil-cooled air compressor according to any one of claims 1 to 9, wherein a specific gravity of the lubricating oil is 0.95 or less.   The oil-cooled air compressor according to any one of claims 1 to 10, wherein the lubricating oil has hydrophobicity. An oil-cooled compressor body that compresses and discharges the sucked air; and
An oil separation and recovery device for separating and recovering the lubricating oil from the compressed air discharged from the compressor body;
An oil supply passage connecting the oil separator and the suction side of the compressor body;
A control method for an oil-cooled air compressor comprising: a cooling water supply passage for supplying cooling water for cooling the air,
A control method for an oil-cooled air compressor, wherein cooling air is supplied by the cooling water supply flow path to cool the air so that the air is below a dew point in the compressor body. An oil-cooled compressor body that compresses and discharges the sucked air; and
An oil separation and recovery device for separating and recovering the lubricating oil from the compressed air discharged from the compressor body;
An oil supply passage connecting the oil separator and the suction side of the compressor body;
A control method for an oil-cooled air compressor comprising: a cooling water supply passage for supplying cooling water for cooling the air,
A control method for an oil-cooled air compressor, wherein cooling air is supplied through the cooling water supply channel to cool the air so that the temperature of the compressed air discharged from the compressor main body is lower than a dew point.

Images