Coolant supply apparatus

Abstract

To separate dispersed oil contained in a coolant and reduce the clogging of a filter.SOLUTION: A coolant supply apparatus 1 includes: a coolant tank 11 configured to store (i) a first coolant C1 supplied to a machine tool 3 and (ii) (a) machining debris and (b) dispersed oil dispersed from the first coolant that flow together with the first coolant from a place supplied; a debris separation section 12 configured to separate the machining debris from a second coolant C2 collected from a coolant stored in the coolant tank 11; and a hydrophilic oil-repellent filter 132 configured to separate the dispersed oil from a third coolant C3 separation-treated in the debris separation section.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a coolant supply device.

Background Art

[0002] As a device attached to a machine tool, a coolant supply device that supplies a water-soluble coolant to the machining area of the machine tool is known. The coolant supplied from the coolant supply device cools the tool tip and the workpiece, and discharges the machining chips generated by machining outside the machining area.

[0003] Since the machine tool has a movable mechanism, lubricating oil is supplied to the machine tool. Therefore, the coolant supplied to the machining area is recovered in the coolant tank with the lubricating oil mixed in. Also, when the workpiece is machined, machining chips are generated. Therefore, the coolant is recovered in the coolant tank with the machining chips mixed in. When lubricating oil or machining chips are mixed in, the performance of the coolant is likely to deteriorate. In addition, when an oil film is formed on the surface layer of the coolant in the tank, anaerobic bacteria multiply and a foul smell is likely to occur.

[0004] In response to such problems, for example, Patent Document 1 discloses the following coolant supply device. That is, the coolant supply device includes a storage tank that stores the coolant used in the machine tool, and a nozzle that sucks the coolant containing machining chips and the oil spreading on the liquid surface from the storage tank. The coolant supply device further includes a sludge separation and dehydration machine that recovers machining chips and the like from the coolant sucked by the nozzle, and a coalescing element that separates oil from the coolant from which the machining chips have been removed. The sludge separation and dehydration machine includes a bag-shaped filter. The bag-shaped filter is composed of a non-woven fabric or the like in which fibers are randomly dispersed. The bag-shaped filter filters the passing coolant and separates the machining chips from the coolant. The coalescing element is composed of an extremely fine fiber sheet such as a non-woven fabric. The coalescing element captures, aggregates, coarsens, and separates the oil in the passing coolant. The coolant that has passed through the coalescing element is returned to the storage tank and supplied to the machine tool again.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] As a method for purifying a coolant containing machining chips and oil, there is a method of filtering the coolant with a filter. However, when filtering both machining chips and oil, the filter is likely to be clogged by the machining chips. Therefore, the life of the filter is likely to be shortened and the replacement frequency is likely to increase. On the other hand, in the coolant supply device of Patent Document 1, after separating the machining chips, the oil is separated. Thereby, the filter for separating the oil has a longer life.

[0007] By the way, as the oil contained in the coolant, there are floating oil floating on the coolant liquid surface, dispersed oil dispersed in the coolant liquid, and the like. The floating oil generally has a size of 200 μm or more. The dispersed oil generally has a size of 2 to 10 μm. Therefore, separating the dispersed oil is more difficult than separating the floating oil.

[0008] In the coolant supply device of Patent Document 1, the dispersed oil is separated by a coalescing element. The coolant passing through the coalescing element passes through the holes (gaps between fibers) of the fiber sheet. The dispersed oil in the coolant is captured by the holes of the fiber sheet. By setting the size of the holes of the fiber sheet, the dispersed oil of a desired size can be separated from the coolant. However, if the holes of the fiber sheet are too small, while the minute dispersed oil can be captured, the holes of the fiber sheet are likely to be clogged. If the holes of the fiber sheet are too large, while the clogging of the holes is reduced, it is difficult to separate the minute dispersed oil.

[0009] An object of the present invention is to separate dispersed oil contained in a coolant and reduce clogging of a filter.

Means for Solving the Problems

[0010] The coolant supply device of the present invention includes (i) a first coolant supplied to a machine tool, and (ii) a coolant tank that stores (a) machining chips and (b) dispersed oil dispersed from the first coolant that flow together with the first coolant from the supplied location, a chip separation unit that separates the machining chips from a second coolant collected from the coolant stored in the coolant tank, a hydrophilic oleophobic filter that separates the dispersed oil from a third coolant separated by the chip separation unit.

Advantages of the Invention

[0011] In the coolant supply device of the present invention, machining chips are separated from the coolant by a chip separation unit before separating the dispersed oil. Thereafter, the dispersed oil is separated from the coolant from which the machining chips have been separated by a hydrophilic oleophobic filter. Therefore, the hydrophilic oleophobic filter is less likely to be clogged by the machining chips. Further, the hydrophilic oleophobic filter has oleophobicity. Therefore, the adhesion of the dispersed oil to the filter is reduced, and the filter is less likely to be clogged by the dispersed oil. Therefore, according to the above coolant supply device, it is possible to separate the dispersed oil contained in the coolant and reduce clogging of the filter.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0014] FIG. 1 is a schematic diagram of the coolant supply device and the machine tool according to the present embodiment. The coolant supply device 1 is attached to the machine tool 3. The coolant supply device 1 supplies a liquid coolant to the machine tool 3. The coolant is not particularly limited. For example, a known coolant used for machine tools is applied as the coolant. The coolant is, for example, an aqueous coolant. The machine tool 3 is not particularly limited. The machine tool 3 cools the workpiece and the tool using the coolant supplied from the coolant supply device 1.

[0015] The coolant supply device 1 includes a coolant tank 11, a debris separation unit 12, and an emulsified oil separation unit 13. The flow of the coolant purification process in the coolant supply device 1 is generally as follows. The first coolant C1 stored in the coolant tank 11 is supplied to the machine tool 3. The first coolant C1 supplied to the machine tool 3 is refluxed to the coolant tank 11. The first coolant C1 stored in the coolant tank 11 is supplied to the debris separation unit 12 and then to the emulsified oil separation unit 13. The coolant supplied to the emulsified oil separation unit 13 returns to the coolant tank 11. Hereinafter, each component will be described in detail.

[0016] The coolant tank 11 includes a primary tank 111 and a secondary tank 112. The primary tank 111 stores the first coolant C1 to be supplied to the machine tool 3. The shape of the primary tank 111 is not particularly limited. The primary tank 111 has, for example, a rectangular shape in plan view. In order to supply the first coolant C1 from the primary tank 111 to the machine tool 3, the coolant supply device 1 includes a supply unit 14. The supply unit 14 includes a supply pipe 141 and a supply pump 142. The supply pipe 141 includes a first end portion that is immersed in the first coolant C1 in the primary tank 111. The first end portion is provided so as to be located below the liquid level of the first coolant C1. The supply pipe 141 includes a second end portion connected to the machine tool 3. The connection destination of the second end portion is not particularly limited. The second end portion is connected to, for example, the part to be cleaned of the machine tool 3. The part to be cleaned is, for example, an oil pan or the like. The supply pump 142 is provided so as to be able to adjust the flow of the coolant in the supply pipe 141. With such a configuration, the supply unit 14 supplies the first coolant C1 stored in the primary tank 111 to the machine tool 3.

[0017] The primary tank 111 stores the first coolant C1 used in the machine tool 3. In order to return the first coolant C1 from the machine tool 3 to the primary tank 111, the coolant supply device 1 includes a reflux unit 15. The reflux unit 15 includes a reflux pipe 151. The reflux pipe 151 includes a first end portion connected to the machine tool 3. The connection destination of the first end portion is not particularly limited. The first end portion is connected to, for example, the coolant recovery portion of the machine tool 3. The reflux pipe 151 includes a second end portion that discharges the first coolant C1 to be returned to the primary tank 111. The second end portion may be provided so as to be located above the liquid level of the first coolant C1 in the primary tank 111, or may be provided so as to be immersed in the first coolant C1. With such a configuration, the reflux unit 15 refluxes the first coolant C1 from the machine tool 3 to the primary tank 111. Note that a filter 152 may be provided at the second end portion of the reflux pipe 151. The filter 152 separates, for example, large machining chips and the like.

[0018] The supply section 14 and the reflux section 15 cause the first coolant C1 to circulate between the first-stage tank 111 and the machine tool 3. In the machine tool 3, machining waste is generated by machining such as cutting and grinding. Also, lubricating oil, cutting oil, etc. are used in the machine tool 3. Therefore, machining waste and dispersed oil flow into the reflux section 15 together with the first coolant C1 supplied to the machine tool 3. The first coolant C1 stored in the first-stage tank 111 contains machining waste and dispersed oil dispersed in the liquid.

[0019] The second-stage tank 112 is provided adjacent to the first-stage tank 111. The shape of the second-stage tank 112 is not particularly limited. The second-stage tank 112 has, for example, a rectangular shape in plan view. The second-stage tank 112 includes a side wall 1121 provided on the first-stage tank 111 side. The side wall 1121 includes an opening 1122. The second-stage tank 112 is configured such that the fourth coolant C4 in the second-stage tank 112 flows into the first-stage tank 111 through the opening 1122.

[0020] The waste separation section 12 separates machining waste from the coolant (referred to as the second coolant C2) collected from the coolant tank 11. The waste separation section 12 includes a pipe 121, a pump 122, and a centrifugal separation filter 123. The pipe 121 includes a sampling port 1211 for sampling the first coolant C1 stored in the first-stage tank 111. The sampling port 1211 is located below the liquid level of the first coolant C1 stored in the first-stage tank 111. In the pipe 121, an end different from the sampling port 1211 is connected to the centrifugal separation filter 123. The pump 122 is provided so as to be able to adjust the flow of the second coolant C2 in the pipe 121. The second coolant C2 sucked by the pump 122 and the pipe 121 contains machining waste and dispersed oil. This second coolant C2 is supplied to the centrifugal separation filter 123. The centrifugal separation filter 123 separates machining waste from the second coolant C2 using centrifugal force. The centrifugal separation filter 123 generates a swirling flow in the second coolant C2 supplied using a propeller. The centrifugal separation filter 123 collects machining waste at the lower part of the filter. The centrifugal separation filter 123 discharges the coolant (referred to as the third coolant C3) from which machining waste has been separated from the upper part.

[0021] A part of the third coolant C3 from which machining chips have been separated by the chip separation unit 12 is transferred to the dispersed oil separation unit 13 by the second transfer unit 17. The second transfer unit 17 includes a second transfer pipe 171 for transferring the coolant. The second transfer pipe 171 includes a first end connected to the coolant discharge port of the chip separation unit 12. The second transfer pipe 171 includes a second end for discharging the third coolant C3 to the dispersed oil separation unit 13. The second transfer unit 17 may include a pump for controlling the flow of the third coolant C3 in the pipe.

[0022] The remainder of the third coolant C3 from which machining chips have been separated by the chip separation unit 12 is transferred to the secondary tank 112 by the third transfer unit 18. The third transfer unit 18 includes a third transfer pipe 181 for transferring the coolant. The third transfer pipe 181 includes a first end connected to the middle of the second transfer pipe 171. A throttle valve 182 is provided at the connection portion between the third transfer pipe 181 and the second transfer pipe 171. The throttle valve 182 adjusts the amount of coolant flowing from the chip separation unit 12 to the third transfer pipe 181 and the amount of coolant flowing from the chip separation unit 12 to the second transfer pipe 171. The third transfer pipe 181 includes a second end for discharging the third coolant C3 to the secondary tank 112. The third transfer unit 18 may include a pump for controlling the flow of the third coolant C3 in the pipe.

[0023] The dispersed oil separation unit 13 includes an oil separation tank 131 and a hydrophilic oleophobic filter 132. The oil separation tank 131 stores the third coolant C3 supplied from the chip separation unit 12. The oil separation tank 131 stores the third coolant C3 from which machining chips have been separated. The oil separation tank 131 stores the third coolant C3 containing dispersed oil. The shape of the oil separation tank 131 is not particularly limited. The oil separation tank 131 has, for example, a rectangular shape in plan view. The hydrophilic oleophobic filter 132 is provided in the oil separation tank 131. The hydrophilic oleophobic filter 132 separates dispersed oil from the third coolant C3 from which machining chips have been separated by the chip separation unit 12. The hydrophilic oleophobic filter 132 has hydrophilicity and oleophobicity.

[0024] FIG. 2(A) is an external view of the hydrophilic oleophobic filter in the coolant supply device of the present embodiment, and FIG. 2(B) is a cross-sectional view of the hydrophilic oleophobic filter. The hydrophilic oleophobic filter 132 includes a first end plate 1321, a second end plate 1322, an outer tube 1325, a hydrophilic oleophobic filter medium 1324, and an inner tube 1323.

[0025] The first end plate 1321 has a hollow cylindrical shape. The second end plate 1322 has the same shape as the first end plate 1321. The first end plate 1321 and the second end plate 1322 sandwich and fix the inner tube 1323, the hydrophilic oleophobic filter medium 1324, and the outer tube 1325.

[0026] The inner tube 1323 has a hollow cylindrical shape. The inner tube 1323 is provided so as to be substantially coaxial with the first end plate 1321 and the second end plate. The inner tube 1323 includes at least one through hole 1326 penetrating the inner tube 1323 in the radial direction. The at least one through hole 1326 opens to the inner surface and the outer surface of the inner tube 1323. The size of the at least one through hole 1326 is not particularly limited. The size of the at least one through hole 1326 is larger than the average size of the dispersed oil. The material of the inner tube 1323 is not particularly limited. Preferably, the inner tube 1323 is made of an oleophobic material.

[0027] The hydrophilic oleophobic filter material 1324 is provided on the outer side of the inner tube 1323. The hydrophilic oleophobic filter material 1324 is provided so as to surround the inner tube 1323 over one circumference. However, the hydrophilic oleophobic filter material 1324 may be provided so as to surround at least a part of the outer surface of the inner tube 1323. The hydrophilic oleophobic filter material 1324 has a bellows shape in the axial direction view. The hydrophilic oleophobic filter material 1324 has a mesh structure so as to allow the coolant and the dispersed oil to pass through. The hydrophilic oleophobic filter material 1324 has a plurality of meshes so as to allow the coolant to pass through. The size of the mesh is smaller than the average size of the dispersed oil. However, the size of the mesh may be larger than the average size of the dispersed oil. The size of the mesh may be such that it substantially does not allow the dispersed oil to pass through. The hydrophilic oleophobic filter material 1324 is composed of an oleophobic material. The oleophobic material is not particularly limited as long as it has oleophobicity. The oleophobic material is, for example, oleophobic polypropylene.

[0028] The outer tube 1325 has a hollow cylindrical shape. The outer tube 1325 is provided so as to be substantially coaxial with the first end plate 1321 and the second end plate. The outer tube 1325 includes at least one through hole 1327 that penetrates the outer tube 1325 in the radial direction. The at least one through hole 1327 opens to the inner surface and the outer surface of the outer tube 1325. The size of the at least one through hole 1327 is not particularly limited. The size of the at least one through hole 1327 is larger than the average size of the dispersed oil. Preferably, the size of the at least one through hole 1327 is smaller than the through hole 1326 of the inner tube 1323. The material of the outer tube 1325 is not particularly limited. Preferably, the outer tube 1325 is composed of an oleophobic material.

[0029] The hydrophilic oleophobic filter 132 with such a structure is provided in the oil separation tank 131. When the third coolant C3 is supplied from the debris separation section 12 into the oil separation tank 131, the third coolant C3 flows into the hydrophilic oleophobic filter 132 through the through hole 1327 of the outer tube 1325. The coolant that has passed through the outer tube 1325 reaches the hydrophilic oleophobic filter medium 1324. The hydrophilic oleophobic filter medium 1324 repels the dispersed oil and allows the coolant that does not contain the dispersed oil (referred to as the fifth coolant C5) to pass through. The dispersed oil repelled by the hydrophilic oleophobic filter medium 1324 passes through the outer tube 1325 and exits outside the hydrophilic oleophobic filter 132. The dispersed oil that has exited outside the hydrophilic oleophobic filter 132 merges with the oil droplets of other dispersed oil and floats on the liquid surface of the oil separation tank 131. On the other hand, the coolant that has passed through the hydrophilic oleophobic filter medium 1324 passes through the through hole 1326 of the inner tube 1323 and reaches the hollow portion of the hydrophilic oleophobic filter 132. By recovering the fifth coolant C5 that has passed through the hydrophilic oleophobic filter 132 in this way, a coolant from which machining debris and dispersed oil have been separated can be obtained.

[0030] Referring to FIG. 1, the fifth coolant C5 from which the dispersed oil has been separated by the hydrophilic oleophobic filter 132 is transferred to the secondary tank 112 by the fourth transfer section 19. The fourth transfer section 19 includes a fourth transfer pipe 191 for transferring the fifth coolant C5. The fourth transfer pipe 191 includes a first end connected to the oil separation tank 131. The first end is provided so as to be able to collect the fifth coolant C5 that has passed through the hydrophilic oleophobic filter 132. The fourth transfer pipe 191 includes a second end that discharges the fifth coolant C5 into the secondary tank 112. The fourth transfer section 19 may include a pump for controlling the flow of the fifth coolant C5 in the pipe.

[0031] As described above, in the coolant supply device 1, before separating the dispersed oil, the machining chips are separated from the coolant by the chip separation unit 12. After that, the dispersed oil is separated from the coolant from which the machining chips have been separated by the dispersed oil separation unit 13. Therefore, in the dispersed oil separation unit 13, the hydrophilic oleophobic filter 132 is less likely to be clogged by the machining chips. Further, the hydrophilic oleophobic filter 132 has oleophobic properties. Therefore, the adhesion of the dispersed oil to the hydrophilic oleophobic filter 132 is reduced, and the hydrophilic oleophobic filter 132 is less likely to be clogged by the dispersed oil. Therefore, according to the coolant supply device 1, it is possible to separate the dispersed oil contained in the coolant and reduce the clogging of the filter.

[0032] <Modification Example 1> FIG. 3 is a schematic view of the coolant supply device according to Modification Example 1 of the present embodiment. This coolant supply device 1A has a configuration in which a mechanism for recovering floating oil is added to the above-described coolant supply device 1. In the coolant supply device 1A, the configuration other than the configuration for recovering the floating oil is the same as that of the above-described coolant supply device 1.

[0033] In the coolant supply device 1A, in the primary tank 111, in addition to the machining chips and the dispersed oil, the floating oil floating on the liquid surface of the first coolant C1 is stored. The coolant supply device 1A includes a floating oil separation unit 20 that separates the floating oil from the first coolant C1 stored in the primary tank 111.

[0034] The floating oil separation unit 20 recovers the floating oil floating on the liquid surface of the first coolant C1 stored in the first-stage tank 111. The floating oil separation unit 20 is, for example, a belt type, screw type, disk type, suction type oil skimmer, etc. The belt type oil skimmer includes a rotating belt partially immersed in the first coolant C1. The belt type oil skimmer adheres the floating oil to the rotating belt and recovers the floating oil from the first-stage tank 111. The screw type oil skimmer includes a screw partially immersed in the first coolant C1. The screw type oil skimmer recovers the floating oil by rotating the screw. The disk type oil skimmer includes a rotating disk partially immersed in the first coolant C1. The disk type oil skimmer adheres the floating oil to the rotating disk and recovers the floating oil from the first-stage tank 111. The suction type oil skimmer includes a suction nozzle provided to contact the floating oil. The suction type oil skimmer recovers the floating oil by sucking the floating oil with the suction nozzle. However, the floating oil separation unit 20 is not limited to the belt type, screw type, disk type, suction type oil skimmer, and any mechanism capable of recovering the floating oil may be used.

[0035] The floating oil recovered by the floating oil separation unit 20 is transferred to the dispersed oil separation unit 13 by the first transfer unit 16. The first transfer unit 16 includes a transfer passage 161 for transferring the floating oil. The transfer passage 161 is not particularly limited as long as it can transfer the floating oil. The transfer passage 161 is, for example, a belt conveyor, a pipe, etc. The transfer passage includes a first end for receiving the floating oil recovered by the floating oil separation unit 20. The transfer passage 161 includes a second end for discharging the floating oil into the oil separation tank 131 in the dispersed oil separation unit 13. The second end is provided above the liquid surface of the third coolant C3 stored in the oil separation tank 131. However, the second end may be provided below the liquid surface of the third coolant C3 stored in the oil separation tank 131.

[0036] The coolant supply device 1A further includes a waste oil recovery mechanism 21 for recovering the floating oil transferred to the dispersed oil separation unit 13 by the first transfer unit 16. The waste oil recovery mechanism 21 is not particularly limited. The waste oil recovery mechanism 21 is, for example, the above-mentioned belt type, screw type, disk type, suction type oil skimmer, etc.

[0037] Thus, in the coolant supply device 1A according to the first modification, the floating oil stored in the primary tank 111 is recovered. Therefore, in addition to the machining chips and the dispersed oil, the floating oil is also separated by the floating oil separation unit 20, the above-described chip separation unit 12, and the dispersed oil separation unit 13. Therefore, according to the coolant supply device 1A, the purification performance of the coolant is further improved.

[0038] Further, in the coolant supply device 1A, the floating oil separation unit 20 separates the floating oil in the primary tank 111. Therefore, it is difficult for the floating oil to mix into the coolant supplied from the primary tank 111 to the chip separation unit 12 and the dispersed oil separation unit 13. Therefore, according to the coolant supply device 1A, the load on the oil separation function of the chip separation unit 12 and the dispersed oil separation unit 13 can be reduced, and the chip separation unit 12 and the dispersed oil separation unit 13 can have a longer service life.

[0039] Further, for example, when the machine tool does not operate for a certain period, the first coolant C1 stored in the primary tank 111 does not circulate between the primary tank 111 and the machine tool 3. Therefore, the primary tank 111 becomes static, and it is difficult for the flow of the first coolant C1 to occur in the primary tank 111. In this case, floating oil is likely to be generated in the primary tank 111. Therefore, if the static state of the primary tank 111 continues, the deterioration of the first coolant C1 is promoted by the floating oil. On the other hand, in the coolant supply device 1A, even when the first coolant C1 is not circulating, the floating oil separation unit 20 can separate the floating oil from the primary tank 111. Therefore, according to the coolant supply device 1A, the coolant can be purified regardless of whether the machine tool is operating or not.

[0040] Furthermore, in the coolant supply device 1A, the first transfer unit 16 transfers the floating oil in the primary tank 111 to the dispersed oil separation unit 13. The floating oil transferred to the dispersed oil separation unit 13 floats on the liquid surface of the third coolant C3 stored in the oil separation tank 131. Here, in the dispersed oil separation unit 13, the dispersed oil repelled by the hydrophilic oleophobic filter 132 is aggregated. As a result, the coarsened dispersed oil floats on the liquid surface of the third coolant C3 stored in the oil separation tank 131. That is, on the liquid surface of the third coolant C3 in the oil separation tank 131, not only the floating oil but also the coarsened dispersed oil floats. If the waste oil recovery mechanism 21 recovers the oil floating on the liquid surface of the third coolant C3 in the oil separation tank 131, both the floating oil and the dispersed oil are recovered together. There is no need to provide a waste oil recovery mechanism for recovering each of the floating oil and the dispersed oil. Therefore, according to the coolant supply device 1A, the floating oil and the dispersed oil can be efficiently recovered, and the structure of the coolant supply device can be made compact.

[0041] Note that in the coolant supply device 1A according to the first modification, the configuration of transferring and recovering the floating oil in the primary tank 111 to the dispersed oil separation unit 13 has been described. However, the floating oil in the primary tank 111 may be recovered in the primary tank 111. That is, the coolant supply device 1A may not include the first transfer unit 16.

[0042] <Modification 2> FIG. 4 is a schematic diagram of the coolant supply device according to the second modification of the present embodiment. This coolant supply device 1B has a configuration in which a stirring unit for stirring the first coolant C1 in the primary tank 111 is added to the above-described coolant supply device 1. In the coolant supply device 1B, the configuration other than the stirring unit is the same as that of the above-described coolant supply device 1.

[0043] The coolant supply device 1B further includes a stirring unit 22 that stirs the first coolant C1 stored in the primary tank 111. The stirring unit 22 includes a stirring pump 221 and a pipe 222. Both ends of the pipe 222 are immersed in the first coolant C1 in the primary tank 111. The coolant flowing into one end of the pipe 222 is discharged from the other end by the stirring pump 221. Thereby, the first coolant C1 in the primary tank 111 is stirred. However, the configuration of the stirring unit 22 is not limited to this. The stirring unit 22 may have any configuration as long as it can cause a flow in the first coolant C1 in the primary tank 111.

[0044] In the primary tank 111, the machining chips tend to settle at the bottom of the tank. By stirring the first coolant C1 in the primary tank 111 by the stirring unit 22, the settled machining chips are easily lifted into the liquid of the first coolant C1. Therefore, according to the coolant supply device 1B, the recovery efficiency of the machining chips is increased.

[0045] FIG. 5 is a diagram showing an example of the arrangement relationship between the coolant supply device and the machine tool of the present embodiment. The coolant supply devices 1, 1A, 1B are provided so that at least a part thereof is accommodated below the machine tool 3. More specifically, the machine tool 3 includes a tool spindle 31 that holds a tool, and workpiece spindles 32, 33 that hold workpieces. The machine tool 3 includes a machining chamber 34 in which the workpiece is machined by the tool spindle 31 and the workpiece spindles 32, 33. The machining chamber 34 is a space formed by a splash guard or the like. The coolant supplied to the machine tool 3 is sprayed into, for example, the machining chamber 34. The coolant sprayed into the machining chamber 34 is collected together with the machining chips by a chip conveyor 35. The chip conveyor 35 conveys the machining chips outside the machine tool 3. The machining chips conveyed outside the machine tool 3 are accommodated in a bucket 36. A primary tank 111 is provided below the chip conveyor 35. The chip conveyor 35 is configured to discharge the collected coolant downward. The primary tank 111 is provided to receive the coolant discharged from the chip conveyor 35.

[0046] The embodiments of the present invention have been described above. However, the description of the above-described embodiments is illustrative in all respects and not restrictive. Modifications and changes can be made as appropriate by those skilled in the art. The scope of the present invention is indicated not by the above-described embodiments but by the claims. Furthermore, the scope of the present invention includes changes from the embodiments within the scope equivalent to the claims.

[0047] For example, in the above-described coolant supply devices 1, 1A, and 1B, the coolant tank 11 includes the primary tank 111 and the secondary tank 112. However, the coolant tank 11 may not include the secondary tank 112. The coolant flowing from the debris separation unit 12 and the dispersed oil separation unit 13 into the secondary tank 112 may flow into the primary tank 111.

[0048] In the above-described coolant supply devices 1, 1A, and 1B, the hydrophilic oleophobic filter 132 has a hollow cylindrical shape as a whole. However, the shape of the hydrophilic oleophobic filter 132 is not limited to this. Also, in the hydrophilic oleophobic filter 132, the coolant to be filtered may pass through the filter from the outside to the inside or from the inside to the outside. In short, the hydrophilic oleophobic filter 132 may be configured to be able to separate dispersed oil from the coolant.

[0049] In the above-described coolant supply devices 1, 1A, and 1B, the debris separation unit 12 separates machining debris. This does not mean that the debris separation unit 12 necessarily separates all of the machining debris contained in the coolant. The debris separation unit 12 may separate all of the machining debris contained in the coolant or may separate a part of it. The same applies to the dispersed oil separation unit 13 and the floating oil separation unit 20.

[0050] In the coolant supply devices 1, 1A, and 1B described above, the dispersed oil separation unit 13 includes the hydrophilic oleophobic filter 132. However, the dispersed oil separation unit 13 may include other filters in addition to the hydrophilic oleophobic filter 132. The other filters are, for example, oleophilic filters, bubble-type oil separation devices, etc. The oleophilic filter is composed of oleophilic fibers. The oleophilic filter captures and separates the dispersed oil by adsorbing the dispersed oil. The oleophilic filter is, for example, a non-woven fabric, etc. The bubble-type oil separation device generates bubbles. The bubble-type oil separation device adsorbs and separates the dispersed oil on the generated bubbles.

[0051] In the coolant supply devices 1, 1A, and 1B described above, the first coolant C1 stored in the first tank 111 is supplied to the machine tool 3. However, the coolant supplied to the machine tool 3 may be stored in a part other than the first tank 111. For example, the fourth coolant C4 stored in the second tank 112 may be supplied to the machine tool 3. The third coolant C3 stored in the oil separation tank 131 may be supplied to the machine tool 3. The fifth coolant C5 from which the dispersed oil has been removed by the hydrophilic oleophobic filter 132 may be supplied to the machine tool 3.

[0052] In the above description, the floating oil and the dispersed oil refer to those existing as oil droplets. The floating oil and the dispersed oil are different from the oil content emulsified in the coolant.

Explanation of Reference Numerals

[0053] 1, 1A, 1B: Coolant supply device 11: Coolant tank 111: First tank 112: Second tank 12: Scrap separation unit 121: Pipe 1211: Sampling port 122: Pump 123: Centrifugal filter 13: Dispersed oil separation unit 131: Oil separation tank 132: Hydrophilic oleophobic filter 1321: First end plate 1322: Second End Plate 1323: Inner Tube 1324: Hydrophilic and Oleophobic Filter Medium 1325: Outer Tube 1326, 1327: Through-Holes 14: Supply Section 15: Return Section 16: First Transfer Section 161: Transfer Passage 17: Second Transfer Section 171: Second Transfer Pipe 18: Third Transfer Section 181: Third Transfer Pipe 182: Throttle Valve 19: Fourth Transfer Section 191: Fourth Transfer Pipe 20: Floating Oil Separation Section 21: Waste Oil Recovery Mechanism 22: Stirring Section 221: Stirring Pump 222: Pipe C1 - C5: Coolant 3: Machine Tool

Claims

1. (i) a coolant tank that stores (i) a first coolant supplied to a machine tool, and (ii) (a) machining chips and (b) dispersed oil dispersed from the first coolant that flow together with the first coolant from the supplied location; a chip separation unit that separates the machining chips from a second coolant collected from the coolant stored in the coolant tank; a coolant supply device comprising a hydrophilic oleophobic filter that separates the dispersed oil from a third coolant separated by the chip separation unit.

2. The coolant supply device according to claim 1, wherein the coolant tank stores floating oil floating on the liquid surfaces of the machining chips, the dispersed oil, and the first coolant, and the coolant supply device further comprises a floating oil separation unit that separates the floating oil from the first coolant stored in the coolant tank.

3. The coolant supply device according to claim 2, wherein the coolant supply device further comprises a first transfer unit that transfers the floating oil separated from the first coolant by the floating oil separation unit to an oil separation tank provided with the hydrophilic oleophobic filter.

4. The coolant supply device according to claim 1, wherein the chip separation unit includes a sampling port that samples the first coolant stored in the coolant tank, and the sampling port is located below the liquid surface of the first coolant stored in the coolant tank.

5. The coolant supply device according to claim 1, wherein the coolant supply device further comprises a fourth transfer unit that transfers the coolant from which the dispersed oil has been separated by the hydrophilic oleophobic filter to the coolant tank.

Images