Oil separator

Abstract

An oil separator (3) which separates gas and liquid in oil-containing air to recover oil-containing liquid, the oil separator (3) comprising: an inlet opening (15) which introduces air, an oil trap (40) which collects oil contained in air, a reservoir (48) which stores liquid flowing out of the oil trap (40), and a discharge opening (16) which discharges air from which oil has been removed, wherein the oil trap (40) includes a glass fiber filter (42) and an impact member (41) that captures oil particles by causing the oil particles to impact the impact member (41), characterized in that the impact member (41) is columnar and has air permeability and comprises a first surface (41a) through which air flows in and a second surface (41b) which is an outer peripheral surface (41b) through which air passing through the impact member (41) flows out, and the glass fiber filter (42) is provided on the outer peripheral surface (41b) of the impact member (41), wherein the glass fiber filter (42) is formed as a film and covers the entire outer peripheral surface (41b) of the impact member (41).

Description

TECHNICAL FIELDThe present invention relates to an oil separator that separates oil contained in air.BACKGROUNDFor example, vehicles such as trucks, buses, and construction machines use compressed air supplied from a compressor directly connected to an internal combustion engine to control systems such as brakes and suspensions. In systems such as brakes and suspensions, the compressed air supplied by the compressor includes water contained in the atmosphere. When the pressurized air containing water enters the systems, an operation failure of the systems may be caused thereby. For this reason, an air dryer is provided downstream of the above compressor to remove water from the compressed air.The air dryer performs a charging mode operation for removing water by passing compressed air through a desiccant and a discharging mode for regenerating the desiccant by discharging the water collected by the desiccant to the outside. The air discharged from the air dryer during the unloading mode contains oil together with water. For environmental reasons, it has been proposed to provide an oil separator for separating and recovering oil from the air discharged from the air dryer.The oil separator separates gas and liquid by impacting the air containing water and oil against an impact member. In such a separation of gas and liquid, air or gas from which water and oil have been removed can be discharged to the outside, and water and oil separated from the air can be recovered in the oil separator as the collected liquid (for example, see Patent Document 1).PRIOR ART DOCUMENTPatent DocumentsPatent Document 1: Japanese Patent Laid-Open Publication No. 2013-234 632 AJP S57-35 819 U describes an oil separator having the features of the preamble of claim 1.Further prior art is known from the documents JP 2011-47 306 A, DE 10 2012 217 019 A1, JP S63-232 815 A, JP 2001-140 759 A and U.S. Pat. No. 5,967,127 A.SUMMARY OF THE INVENTIONProblem of the InventionAlthough the impact member is used for separating gas and liquid as described above, the air discharged from the oil separator still contains a very small amount of oil. Therefore, there is a need to increase the oil collection rate of the oil separator.Accordingly, it is an object of the present invention to increase the oil collection rate of an oil separator.Solution to ProblemsA structure and an operation for achieving the above object will be described below.To achieve the above object, an oil separator is provided which separates gas and liquid into air containing oil to recover liquid containing oil. The oil separator comprises the features of claim 1.In this configuration, the impact member traps oil particles having relatively large particle sizes from the oil particles contained in the air. The glass fiber filter traps oil particles having relatively small particle sizes. This improves the oil collection rate of the oil separator.In the configuration of the present invention, most of the air passed through the impingement member can pass through the glass fiber filter. As a result, the oil collection rate is further increased.The oil separator is preferably configured such that the impact member is formed of a urethane foam.With this configuration, because the impact member is formed of a urethane foam, the impact member can be easily press-fitted to a predetermined position in the oil separator together with the glass fiber filter.In order to achieve the object mentioned above, an oil separator is also provided which has the features of claim 3.In this configuration, because the oil trap includes a plurality of filters having different collection rates depending on the particle sizes, the oil collection rate of the oil separator is improved.The oil separator is configured such that the filters included in the oil trap include a first filter having a high trapping rate for oil particles having a large particle size and a second filter having a high trapping rate for oil particles having a small particle size. Further, the oil trap preferably includes the first filter at a position near the insertion opening.With this configuration, because the first filter having a high trapping rate for oil particles having large particle sizes is provided at a position near the introduction opening, air in which large oil particles are reduced by passing through the first filter flows into the second filter having a high trapping rate for oil particles having small particle sizes. Thereby, the removal performance of the second filter for removing small oil particles is maximized.EFFECTS OF THE INVENTIONThe present invention increases the oil collection rate of the oil separator.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a schematic view showing a compressed air drying system according to a first embodiment. FIG. 2 is a side view of the oil separator according to the first embodiment. FIG. 3 is a plan view of the oil separator according to the first embodiment. FIG. 4 is a cross-sectional view of the oil separator taken along line 4- 4 of FIG. 3. FIG. 5 is a perspective view of the oil trap according to the first embodiment of the invention. FIG. 6 is a perspective view of an oil trap according to an example, not an embodiment of the invention. FIG. 7 is a cross-sectional view of an oil separator according to the example of FIG. 6. FIG. 8 is a plan view of an oil trap according to a modification. FIG. 9 is a cross-sectional view of an oil trap according to a modification. FIG. 10 is a plan view of an oil trap according to a modification. FIG. 11 is a cross-sectional view of an oil trap according to a modification not according to the present invention.First EmbodimentAn oil separator according to a first embodiment will be described with reference to FIGS. 1 to 5.As shown in FIG. 1, a compressed air drying system includes a compressor 1, an air dryer 2, and an oil separator 3.The air dryer 2 includes a drying agent and a filter for collecting oil mist. The drying agent absorbs water contained in the compressed air primarily as water vapor. The filter traps oil particles contained in the compressed air. The air dryer 2 performs a charging mode operation for collecting water and oil in the compressed air and a discharging mode operation for discharging water and oil collected by, for example, the desiccant to the outside. During the charging mode operation, the dried compressed air flown out of the air dryer 2 is supplied to, for example, the air system of the brake and the air suspension. Air (winding air) executed by executing the unloading mode operation and liquid containing water and oil are supplied to the oil separator 3. The ratio and state of water and oil discharged from the air dryer 2 during the discharge mode operation differ depending on factors such as the type and state of the compressor 1 and the humidity and temperature of the outside air. For example, water and oil are discharged from the air dryer 2 in a state where the water and oil are contained in the winding air, while the collected liquid does not necessarily need to be discharged.The oil separator 3 removes water and oil contained in the purge air and recovers collected liquid. The air obtained by removing water and oil from the purge air is discharged as purified air into the atmosphere.The following describes the structure of the oil separator 3 with reference to FIGS. 2 to 5.As shown in FIG. 2, the oil separator 3 includes a cylindrical housing 11 having a closed end and a lid 12 that seals the opening part of the housing 11. A drain outlet 13 for discharging collected liquid stored in the oil separator 3 is provided at the bottom part of the housing 11. A drain hose 14 used for the removal of collected liquid is connected to the drain outlet 13.An exhaust port 16 for exhausting clean air is provided on the lid 12. An air discharge hose 20 that discharges clean air to the atmosphere is connected to the discharge port 16 via a discharge coupling member 19. The lid 12 also has a mounting plate 29 that fixes the oil separator 3 to a receiving body such as a vehicle body.As shown in FIG. 3, the lid 12 has, in addition to the aforementioned discharge port 16, a discharge port 15 that introduces air discharged from the air dryer 2. A hose for supplying air flown out of the air dryer 2 is connected to the introduction port 15 via an introduction coupling member 18.As shown in FIG. 4, the lid 12 is cylindrical and the vertically upper end is closed. Two baffle plates 21 are provided in the lid 12 in the vicinity of the insertion opening 15. The baffles 21 stand upright so as to be perpendicular to the flow direction of the purge air introduced through the introduction opening 15. The lid 12 also includes a connecting part 23 that connects the inside of the housing 11 to the discharge port 16.A disk-shaped cover 25 is provided between the housing 11 and the lid 12. The housing 11, the cover 25 and the lid 12 are fastened to each other by fastening screws 27 into through holes in a flange part 26 of the housing 11, through holes in the cover 25 and threaded holes in the lid 12.The space defined by the cover 25 and the lid 12 functions as a first expansion chamber 22, and a communication hole 28 is formed in the central part of the cover 25. Further, a cylindrical receiving member 30 having a lid is fixed to the bottom surface of the cover 25 by means of screws 38. Flange portions 31, 32 are formed at the upper end and the lower end of the receiving member 30, respectively. The receptacle member 30 is fixed to the cover 25 by inserting the screws 38 through the flange part 31. The space defined by the upper surface of the fixed receiving member 30 and the cover 25 functions as a second expansion chamber 33. The above-mentioned communication hole 28 formed in the cover 25 communicates the first expansion chamber 22 with the second expansion chamber 33.Through holes 35 are formed in the central part of an upper wall 34 of the receiving member 30. The through holes 35 and the communication hole 28 of the cover 25 are formed at positions not facing each other. Through holes 36 are formed at the lower end of the side wall of the receiving member 30 at intervals in the circumferential direction.The receiving member 30 receives an oil trap 40 which removes oil contained in purge air. The oil trap 40 includes a first filter that is an impact member 41 and a second filter that is a glass fiber filter 42. The impact member 41 is formed of a porous plastic sponge (urethane foam), and is pillar-shaped in a state where the impact member 41 is accommodated in the accommodation member 30.The glass fiber filter 42 is formed as a sheet and wound around a second surface or an outer circumferential surface 41 bof the columnar impact member 41. Porous plates 43 are respectively provided on a first surface or an upper surface 41 aand a lower surface of the impact member 41 to hold the impact member 41.A retaining washer 45 for retaining the oil trap 40 is fixed to the flange portion 32 formed at the lower end of the receiving member 30 by means of bolts 46. The retainer disc 45 has a diameter substantially equal to the inner diameter of the housing 11. The retainer disc 45 includes through holes 47 which allow liquid oil collected by the oil trap 40, for example, to drain.A reservoir, which is a collected liquid storage part 48 in this embodiment, is provided at the lower portion of the housing 11 and stores the collected liquid dropped through the through holes 47. A heater 49 for heating the stored liquid for water evaporation is provided in the collected liquid storage part 48. The heating of the heater 49 is controlled using a not-shown thermostat.The oil trap 40 will be described below with reference to FIG. 5. The impact member 41 is formed in a columnar shape by rolling both ends of a rectangular parallelepiped sponge upward and approaching each other. The glass fiber filter 42 has a height and width sufficient to cover all surfaces other than the flat surface and the bottom surface of the columnar impact member 41, i.e., the outer circumferential surface 41 b. The impact member 41 is accommodated in the accommodation member 30, with the outer circumferential surface 41 bbeing covered with the glass fiber filter 42. The impact member 41 and the glass fiber filter 42 wound around the impact member 41 may be accommodated in the accommodation member 30 in a state of being fixed to each other by an adhesive or not being fixed to each other.In this embodiment, the thickness of the glass fiber filter 42 is smaller than the diameter of the impact member 41 and the volume of the impact member 41 is larger than the volume of the glass fiber filter 42. However, the ratio may be adjusted as necessary in accordance with, for example, the oil-collecting performance of a sponge and the glass fibers, as well as other factors in the air-under-pressure drying system.The impact member 41 finely changes the air flow in the holes in the sponge and causes oil particles moving with the air flow to impact against the impact member 41 due to the force of inertia thereof, thereby collecting the oil particles. Within the oil particles contained in the purge air as oil, many of the oil particles captured by the impingement member 41 have relatively large particle sizes.The glass fiber filter 42 contains glass fibers, and can be formed by, for example, fixing glass fibers to a base material such as a non-woven fabric, compressing only glass fibers, or compressing glass fibers together with other materials. The glass fiber filter 42 has a fiber diameter, a pore diameter, and a density in the depth direction that allow fine oil particles undergoing Brownian motion in the compressed air to be collected.Using the inertial force impact described above, large oil particles having particle sizes greater than or equal to 1 μm are captured most efficiently, but this depends on the flow velocity of the air. The number of small oil particles contained in the compressed air is larger than the number of large oil particles. The small oil particles collide with gas molecules in the compressed air and make random movements (Brownian movement) regardless of the flow of the compressed air. The particle size of the oil particles undergoing random motion is, for example, less than or equal to 50 nm. Such oil particles are difficult to catch by the method using an inertial impact and more efficiently by contact with glass fibers. Oil particles having an average particle size of, for example, more than 50 nm and less than 1 μm can be captured by both the impact member 41 and the glass fiber filter 42, but thereby the efficiency is somewhat lowered. In other words, because the size of the oil particles efficiently captured by the impact member 41 is different from the size of the oil particles efficiently captured by the glass fiber filter 42, oil particles having a wide range of sizes can be captured.Although the number of oil particles having small particle sizes in the purge air is relatively large as generally described above, the ratio between the total volume of oil particles having large particle sizes and the total volume of oil particles having small particle sizes differs depending on the individual differences of the compressor 1 and the operating atmosphere (such as the temperature and the humidity). However, the trapping performance in trapping oil particles may be adjusted by changing the ratio between the volume of the impact member 41 and the volume of the glass fiber filter 42. That is, the configurations such as the size of the impact member 41 and the thickness of the glass fiber filter 42 are not limited to those shown in FIGS. 4 and 5, for example, and may be changed as needed. For example, the volume of the glass fiber filter 42 may be larger than the volume of the impact member 41.Next, the operation of the oil separator 3 having the above-described configuration will be described with reference to FIG. 4.The purge air discharged from the air dryer 2 flows into the oil separator 3 through the introduction part 15 as indicated by the direction of the arrow in the drawing. The purge air introduced through the introduction port 15 impinges on the baffles 21, and is then introduced into the first expansion chamber 22 to be expanded.The purge air expanded in the first expansion chamber 22 flows into the second expansion chamber 33 through the communication hole 28 formed in the cover 25, and is then expanded. The purge air continues to flow through the through holes 35 in the top wall 34 of the receiver member 30 into the oil trap 40 in the receiver member 30, and the purge air that has flowed into the oil trap 40 first passes through the impingement member 41. In this way, oil particles with large particle sizes contained in the purge air are collected. Water contained in the flushing air is also collected.The purge air in which the number of oil particles having relatively large particle sizes has been reduced flows into the glass fiber filter 42. The glass fiber filter 42 mainly traps oil particles having relatively small particle sizes remaining in the purge air as described above. Water contained in the flushing air is also collected.The liquid water and oil collected by the oil trap 40 move through the oil trap 40, reach the upper surface of the holding disk 45, and drip through the through holes 47 in the holding disk 45 to be stored in the collected liquid storage part 48. When the collected liquid flows into the oil separator 3, the liquid moves along the same path as described above, passes through the oil trap 40, and drips into the collected liquid storage part 48.The collected liquid stored in the collected liquid storage part 48 is heated by the heater 49, so that the water evaporates. The collected liquid stored in the collected liquid storage part 48 is discharged through the discharge hose 14 as needed.The purified air, from which water and oil have been removed by the oil trap 40, flows through the through holes 36 in the side surface of the receiving member 30 into the space formed between the receiving member 30 and the housing 11. The air that has passed through the space passes through a communication hole 50 formed in the cover 25 and a communication part 23 in the lid 12, and is then discharged through the discharge port 16 (see FIG. 2 or 3 ).The first embodiment offers the following advantages. (1) The impingement member 41 mainly traps oil particles having large particle sizes from the oil particles contained in the air, and the glass fiber filter 42 mainly traps oil particles having small particle sizes. Thus, oil particles having a wide range of sizes can be collected as a whole, thereby improving the oil collection rate of the oil separator 3. (2) The glass fiber filter 42 is disposed on the outer circumferential surface 41 bof the impact member 41. The air in which oil particles having large particle sizes have been reduced by passing through the impingement member 41 flows into the glass fiber filter 42, and as a result, the removal performance of the glass fiber filter 42 for removing the oil particles having small particle sizes is maximized. (3) Since the sheet-like glass fiber filter 42 is wound around the entire circumferential surface 41 bof the impact member 41, most of the air passed through the impact member 41 also passes through the glass fiber filter 42. This further increases the oil collection rate. (4) The oil trap 40 includes the impact member 41 formed of a sponge. Therefore, an inertial impact of oil particles occurs on the impact member 41, thereby causing the oil particles to be caught. Moreover, since the impact member 41 and the glass fiber filter 42 are both formed of a material that can be easily compressed, the impact member 41 around which the glass fiber filter 42 is wound can be easily pressed into the receiving member 30.By way of example, yet another oil separator is described, not a claim-specific embodiment.The description focuses on the differences between the first embodiment and this example. In the oil separator according to this example, only the structure of the oil trap is different from that of the oil separator of the first embodiment. Therefore, repeated description of the other configurations will be omitted here.As shown in FIG. 6, the oil trap 40 includes the columnar impact member 41 and a pair of glass fiber filters 44 placed on the top surface 41 aand the bottom surface 41 cof the impact member 41. The optical fiber filters 44 have substantially the same structure as in the first embodiment and are formed in a circular shape.As shown in FIG. 7, in a state where the oil trap 40 is accommodated in the accommodation member 30, the upper glass fiber filter 44 is disposed below the upper wall 34 of the accommodation member 30, and the lower glass fiber filter 44 is disposed on the holding disk 45.The operation of this example will be described below.The purge air in the second expansion chamber 33 flows into the receiver member 30 through the through holes 35 in the top wall 34, and first passes through the glass fiber filter 44 Mainly, the oil particles having small particle sizes are collected among the oil particles contained in the purge air. The purge air passed through the upper glass fiber filter 44 flows into the impingement member 41 and, as in the first embodiment, mainly the oil particles having large particle sizes are collected.A portion of the purge air passed through the impingement member 41 passes through the lower fiberglass filter 44 and then back through the interior of the impingement member 41 or the space between the impingement member 41 and the sidewall of the receiver member 30 to outflow to the outside through the through holes 36 in the sidewall of the receiver member 30. A portion of the purge air does not pass through the lower glass fiber filter 44 and flows out of the receiver member 30 to the outside. The purified air that has flown out from the accommodating member 30 passes through an accommodating hole 50 formed in the cover 25 and the connecting part 23 of the lid 12 and is discharged through the accommodating hole 16. The liquid water and oil collected by the oil trap 40 pass through the oil trap 40 and are stored in the collected liquid storage part 48.As described above, the present example provides the following advantages in addition to the advantages (1), (3), and (4).(5) The glass fiber filter 44 is formed on the upper surface 41 aof the impingement member 41 through which the purge air flows in. Thus, when the purge air flows into the oil trap 40 in the initial stage, most of the purge air passes through the glass fiber filter 44. the structure increases the oil collection rate of the impingement member 41 because the purge air in which the number of small oil particles is reduced flows into the impingement member 41. Because the pair of glass fiber filters 44 include the impact member 41, the contact area between the purge air and the glass fiber is increased. As a result, the oil collection rate of the oil separator 3 is increased.Other ExamplesThe above-described examples may be modified as follows.As shown in FIG. 8, the oil trap 40 may include a plurality of impact members including a first impact member 61 formed by rolling up a rectangular parallelpiped-shaped sponge such that the ends of the sponge approach each other, a cylindrical second impact member 62 disposed on the outside of the first impact member 61, and a cylindrical third impact member 63 disposed on the outside of the second impact member 62. The second impact member 62 and the third impact member 63 are formed by rolling up a rectangular parallelepiped-shaped or plate-shaped sponge such that the ends of the sponge approach each other. A first glass fiber filter 71 wound around the outer periphery of the first impact member 61 is disposed between the first impact member 61 and the second impact member 62. A second glass fiber filter 72 wound around the outer periphery of the second impact member 62 is disposed between the second impact member 62 and the third impact member 63. Further, a third glass fiber filter 73 is wound around the outside of the third impact member 63. A connection part 61 aof the first impact member 61, a connection part 71 aof the first glass fiber filter 71, a connection part 62 aof the second impact member 62, a connection part 72 aof the second glass fiber filter 72, a connection part 63 aof the third impact member 63, and a connection part 73 aof the third glass fiber filter 73 are arranged at different positions in the circumferential direction of the oil trap 40. Since the connecting parts 61 ato 63 aand 71 ato 73 aare disposed at different positions as described above, even if air enters the oil trap 40 from arbitrary positions, the connecting parts 61 ato 63 aand 71 ato 73 ado not impede the flow of the air into the oil trap 40, thus allowing the air to reliably pass through the oil trap 40.As shown in FIG. 9, impact members made of a sponge and glass fiber filters may be laminated in the axial direction of the columnar oil trap 40. For example, five impactors 91 to 95 may be disposed between six fiber optic filters 81 to 86. Further, a glass fiber filter 87 may be wound around the outer periphery of a laminated body in which the glass fiber filters 81 to 86 and the impact members 91 to 95 are contained.As shown in FIG. 10, multiple glass fiber filters may be wound around the impact member to adjust the thickness of the glass fiber filter. For example, the oil trap 40 includes a first impact member 100 that is a rectangular parallelepiped-shaped sponge rolled up such that the ends of the sponge approach each other, and a second impact member 101 wound around the outer periphery of the first impact member 100. Three glass fiber filters 102 to 104 are wound around the outer periphery of the second impact member 102. These glass fiber filters 102 to 104 may have the same or different characteristics such as weight per volume. In this configuration, the thickness of the glass fiber filter layer is adjusted to control the oil trap performance. A glass fiber filter may also be provided between the first impact member 100 and the second impact member 102.As shown in FIG. 11, impact members made of sponge and glass fiber filters may be laminated in the axial direction of the columnar oil trap 40, and the thickness of the glass fiber filters may be adjusted by the number of laminated glass fiber filters. For example, three glass fiber filters 112 to 114 may be laminated on one of the axial end surfaces of each pair of impact members 110, 111. In this case, the thickness of the glass fiber filter layer is adjusted to control the oil trap performance. A glass fiber filter may also be provided between the impact members 110, 111.In each of the above examples, the thickness of the glass fiber filter 42 is smaller than the diameter of the columnar impact member 41 and the volume of the glass fiber filter 42 is smaller than the volume of the impact member 41. For example, the thickness of the glass fiber filter 42 may be set larger than the diameter of the columnar impingement member 41 or the volume of the glass fiber filter 42 may be set larger than the volume of the impingement member 41, depending on factors of the air drying system, the oil trap performance of the glass fiber filter 42, and the like.In each of the above examples, the impact member 41 and the glass fiber filter 42 also catch water, but do not necessarily catch water.The impact member 41 can catch oil particles that are electrically charged and are suspended in the air using an electrostatic force.In each of the above examples, the impact member is configured by the impact member 41, but may be configured by a fine porous metal material (such as a crushed aluminum member) or baffles.In the above examples, the discharge hose 14 is connected to the discharge outlet 13 of the housing 11. However, the drain hose 14 may be omitted, and a plug may be provided in the drain outlet 13 to drain liquid directly from the drain outlet 13.In the above-described examples, the first expansion chamber 22 and the second expansion chamber 33 are provided in the oil separator 3. However, it is also possible to dispense with the first expansion chamber 22 or the second expansion chamber 33, and therefore only a single expansion chamber can be provided.A plurality of heaters 49 may also be provided, and the heater 49 may also be omitted.The glass fiber filter may be provided so as to cover the upper surface 41 a(the first surface) and the outer circumferential surface 41 b(the second surface) of the impact member 41. The glass fiber filter may also be provided so as to cover all surfaces of the impact member 41.In the example of FIG. 6, the glass fiber filter 44 provided on the bottom surface 41 cof the impact member 41 may be omitted depending on, for example, the oil trap performance of the filter itself.Apart from the oil trap 40, the configuration of the oil separator 3 may be different from the configuration in each of the above-described examples. For example, the oil separator 3 may be a cartridge in which the receptacle member 30 is fixed to the main body including the housing 11 with a threaded part. The cover 25 can also be dispensed with. Further, the structure for connecting the introduction port 15 to the air dryer hose and the structure for connecting the discharge port 16 to the air discharge hose 20 may be other known connecting structures.In each of the above examples, the air that has passed through the oil trap 40 can flow out of the receiving member 30 through the through holes 36 in the side wall of the receiving member 30. However, a through hole for discharging air may be formed in the bottom wall of the receiving member 30. In this case, the second surface from which the air having passed through the impact member 41 flows out is the bottom surface of the impact member 41.In each of the examples described above, the oil trap 40 is configured by the impact member made of urethane foam and the glass fiber filter, but may be configured by any other filters having different collection rates for collecting oil particles depending on particle sizes. The oil trap 40 can thus be configured by filters having the highest collection rate for different particle sizes. For example, the oil trap 40 may be configured by impacting members each having a high capture rate for a different particle size.In each of the examples described above, the oil separator 3 allows purge air to flow from the vertically upper portion of the oil trap 40 into the oil trap 40. However, scavenging air may also flow in from the vertically lower portion of the oil trap 40 or from the outer circumferential surface of the oil trap 40. An impact member having a high collection rate for oil particles having a large particle size may be disposed on the surface of the oil trap 40 through which purge air is disposed depending on the size distribution of the oil particles included in the purge air. Alternatively, a glass fiber filter having a high collection rate for oil particles having a small particle size may be provided.In the examples described above, the oil separator 3 is provided in the exhaust system of the air dryer 2 that is disposed downstream of the compressor 1 of the air system. However, the oil separator 3 may also be provided downstream of the compressor of the air system and upstream of the air dryer 2. In this case, oil is separated from the air containing lubricant, for example, in the compressor 1, and purified air is supplied to the air dryer 2. In this way, the drying agent in the air dryer 2 is prevented from being affected by the oil.LIST OF REFERENCE NUMERALS1 .. Compressor; 2... Air dryer; 3... Oil separator; 11... Housing; 12,... Cover; 13... Discharge outlet, 14... Discharge hose; 15... Insertion opening; 16... Discharge opening; 18... Insertion coupling member; 19... Execution Coupler; 20... Air discharge hose; 21... Baffle plate; 22... first expansion chamber; 23... Connection part; 25... Cover; 26... Flange part; 27... Screw; 28... Communication hole; 29... Mounting plate; 30... Receiving member; 31... Flange part; 32... Flange part; 33... second expansion chamber; 34... top wall; 35... Through hole; 36... Through hole; 40... Oil trap; 41... Impact member; 41a... upper surface; 41b... Outer peripheral surface; 41c... Bottom surface; 42... Glass fiber filters; 43... Plate; 44... Glass fiber filters; 45... Holding disk; 46... Screw; 47... Through hole; 48... Collected liquid storage part; 49... Heater; 50... Communication hole.

Claims

An oil separator (3) that separates gas and liquid into oil-containing air to recover oil-containing liquid, the oil separator (3) comprising: an introduction port (15) that introduces air; an oil trap (40) that traps oil contained in air; a reservoir (48) that stores liquid flown out of the oil trap (40); and an outflow port (16) that executes air from which oil has been removed, wherein the oil trap (40) includes a glass fiber filter (42) and an impact member (41) that traps oil particles by making the oil particles impact against the impact member (41), characterized in that the impact member (41) is pillar-shaped and has air permeability, and a first surface (41a) through which air flows, and a second surface (41b) which is an outer circumferential surface (41b) through which air passed through the impact member (41) flows out, and the glass fiber filter (42) is provided on the outer circumferential surface (41b) of the impact member (41), wherein the glass fiber filter (42) is formed as a sheet and covers the entire outer circumferential surface (41b) of the impact member (41).The oil separator (3) according to claim 1, wherein the impact member (41) is formed of a urethane foam.An oil separator (3) comprising: an introduction port (15) that introduces exhaust gas; an oil trap (40) that traps oil contained in exhaust gas; a reservoir (48) that stores liquid that has flowed out of the oil trap (40) and contains oil; and an discharge port (16) that discharges exhaust gas from which the oil has been removed, wherein the oil trap (40) includes a plurality of filters each having a trapping rate corresponding to the particle sizes of oil particles, wherein the filters have different trapping rates, wherein the filters included in the oil trap (40) include: a first filter (41) having a high trapping rate for oil particles having a large particle size; and a second filter (42) having a high trapping rate for oil particles having a small particle size, wherein the oil trap (40) includes the first filter (41) at a position near the insertion opening (15), characterized in that the first filter is pillar-shaped as an impact member (41) and has air permeability and comprises a first surface (41a) through which air flows in and a second surface (41b) which is an outer circumferential surface (41b) through which air passed through the impact member (41) flows out, and the second filter (42) is a glass fiber filter (42) provided on the outer circumferential surface (41b) of the impact member (41), the glass fiber filter (42) being formed as a sheet and covering the entire outer circumferential surface (41b) of the impact member (41).

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