Floating matter recovery device

Abstract

To provide a floating matter recovery device capable of efficiently recovering floating matters such as scum and oil floating on the liquid surface of a coolant.SOLUTION: A floating material recovery device 1 includes a scum separation tank 2 that is open at the top and has an interior divided into two spaces by a partition plate 12, a coolant tank 4 that stores a scum 11a and a coolant 11b, and a float suction 5 installed inside the coolant tank 4. The scum separation tank 2 is provided with a scum discharge port 2a below which a scum tank 9 is installed, a scum supply port 2b connected to a scum supply pipe 13, and a coolant discharge port 2c connected to a coolant discharge pipe 3. The floating material recovery device has a suction cup that moves up and down by the action of an air cylinder. One end of a scum suction pipe 6, in which a filter 7 and an air-driven diaphragm pump 8 are interposed, is connected to the suction port of the float suction 5 that is floated on the liquid surface of the coolant 11b.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a device for recovering scum (foamy floating residue) and oil that becomes mixed into coolant (cooling liquid) used to lubricate and cool the machining parts of machine tools, and in particular to a floating matter recovery device that can efficiently recover floating matter such as scum and oil that rises to the surface of the coolant. [Background technology]

[0002] In machining processes such as forging and heading, the surface of the workpiece is subjected to a bonder treatment (a process in which a lubricating film is formed on the surface of the workpiece by phosphate coating), but the lubricating film formed on the surface of the workpiece peels off during finishing grinding and gets mixed into the coolant. This lubricating film then chemically reacts with the sliding surface oil and coolant, generating a large amount of scum. Conventionally, as a device for recovering floating matter such as floating oil (oil with a light specific gravity that floats on water) and scum from the liquid surface, for example, a recovery device disclosed in Patent Document 1 includes a tank in which a mixed liquid such as floating oil and sludge is stored, a flexible hose installed in the tank and connected to the inlet of the mixed liquid, two or more floats attached to the flexible hose so that the inlet is positioned at the tank's liquid surface, and a pump case in which the floats are fixed and which surrounds the immersed part of a low-level underwater pump or coolant pump, with the mixed liquid outlet connected to the flexible hose being maintained at a position higher than the water level in the pump case so that the mixed liquid flows into the pump case at atmospheric pressure from the mixed liquid outlet.

[0003] With this structure, the oil and sludge floating on the liquid surface can be efficiently sucked up in response to the fluctuation of the liquid level. However, this recovery device requires the low-level submersible pump or coolant pump to be operated to keep the mixed liquid outlet higher than the water level in the pump so that the mixed liquid flows into the pump case from the mixed liquid outlet at atmospheric pressure, which results in poor operability. In addition, a float is installed on the flexible hose so that even if the liquid level in the tank fluctuates, the mixed liquid inlet of the flexible hose moves up and down to follow the fluctuation. However, if the liquid level in the tank moves downward and the head distance between the mixed liquid inlet and the mixed liquid drop port of the flexible hose is no longer sufficiently secured, there is a problem that the flow of the mixed liquid into the mixed liquid inlet will stop. Furthermore, if the immersion distance between the liquid surface in the tank and the mixed liquid inlet is outside the range of 1 mm to 5 mm, the effect of air and floating objects flowing into the mixed liquid inlet while generating eddies together with the mixed liquid may not be fully achieved.

[0004] To address such issues, for example, Patent Document 2 discloses an invention entitled "Scum Recovery Device" that efficiently separates and recovers scum that has floated to the surface of the coolant from the coolant. The invention disclosed in Patent Document 2 is characterized by comprising a scum separation tank having a scum discharge port provided at the top and a scum supply port and a coolant discharge port provided at the bottom, a scum overflow level adjustment mechanism connected to the coolant discharge port, a coolant tank in which coolant is stored together with scum, a float suction installed inside the coolant tank, an overflow shutter mechanism installed at the scum discharge port, a scum suction pipe having one end connected to the scum supply port and the other end connected to the suction port of the float suction, a filter and an air-driven diaphragm pump installed in the scum suction pipe, and a scum tank installed below the scum discharge port.

[0005] Furthermore, Patent Document 3 discloses an invention entitled "Surface Liquid Recovery Apparatus" which relates to an apparatus for recovering surface liquid containing machine oil, foreign matter, etc. that has floated to the surface of the liquid. The invention disclosed in Patent Document 3 comprises a cylindrical, bellows-shaped expandable member, an annular float installed at the upper end of the expandable member, and a bottom plate member that closes the bottom surface of the expandable member, and is structured so that the surface liquid that flows into the inside of the expandable member is successively transferred from the discharge pipe to a separation tank by driving a pump. In the recovery device with the above structure, when the surface liquid accumulated in the expandable member does not reach the float, the expandable member contracts due to its own weight and the weight of the float. In contrast, when the surface liquid accumulated in the expandable member reaches the top of the float, the float rises together with the surface liquid level due to the buoyancy of the surface liquid. In this case, the expandable member on whose upper end the float is installed also expands to follow the rise of the float. Then, when the surface liquid in the expandable member is transferred to the separation tank via the discharge pipe and the surface liquid level in the expandable member drops, the float descends accordingly, and the expandable member contracts again. In this way, in the invention disclosed in Patent Document 3, the expandable member repeatedly contracts and expands at a predetermined cycle depending on the amount of surface liquid accumulated inside, causing a certain amount of liquid to flow into the expandable member. Therefore, in the invention disclosed in Patent Document 3, it is possible to sequentially recover a certain amount of surface liquid accumulated inside the expandable member. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2013-230458 A [Patent Document 2] Patent Publication No. 2023-50812 [Patent Document 3] JP 2014-12245 A Summary of the Invention [Problem to be solved by the invention]

[0007] A large amount of coolant is consumed in a grinding machine due to adhesion to the workpiece, etc. For example, when a grinding machine is operated for 24 hours, the liquid level in the coolant tank may drop by more than 10 cm. In addition, when a large amount of coolant is returned from the scum separation tank to the coolant tank, the liquid level in the coolant tank fluctuates drastically. In the invention disclosed in Patent Document 2, the suction cup is suspended in the coolant inside the coolant tank. Therefore, if the liquid level inside the coolant tank changes significantly or fluctuates violently, the suction cup can easily tilt, causing the risk of more coolant than necessary flowing into the tank.

[0008] Furthermore, in order to efficiently collect scum from the coolant, it is necessary to adjust the height of the inlet surface of the suction cup relative to the liquid level in the coolant tank. However, in the invention disclosed in Patent Document 2, it was difficult to adjust the height of the inlet surface of the suction cup described above, leaving room for improvement. The invention disclosed in Patent Document 3 requires that the bottom plate member be fixed to the vat, and so when the vat is large, it must be installed close to the side plate, and cannot be installed far away from the side plate. In addition, when installing or removing the device, the bottom plate member must be fixed to the vat or removed from the vat, resulting in poor work efficiency.

[0009] The present invention has been made in response to such conventional circumstances, and aims to provide a floating matter recovery device capable of efficiently recovering floating matter such as scum and oil that has risen to the surface of coolant. [Means for solving the problem]

[0010] In order to achieve the above object, a first invention is a floating matter recovery device for recovering floating matter such as scum and oil that floats to the surface of a coolant used for lubricating and cooling a machining part in a machine tool, the floating matter recovery device comprising: a coolant tank in which coolant is stored together with the floating matter; a float suction device having a float made of a material having a smaller specific gravity than the coolant and installed in the coolant tank so as to float on the surface of the coolant so that floating matter floating on the surface of the coolant can flow into the inside; The float suction system comprises a floating matter separation tank, a floating matter suction pipe having one end connected to the floating matter supply port of the floating matter separation tank and the other end connected to the suction port of the float suction, and a pump which sends floating matter from the float suction pipe to the floating matter separation tank, and the float suction system comprises a connecting plate to which a float is connected, an air cylinder installed on the connecting plate with the tip of the piston rod facing downward, and a suction cup having a suction port at the bottom and connected to the tip of the piston rod in an upward opening position.

[0011] In the first invention, when a float suction is floated on the surface of the coolant stored in a coolant tank, if the upper end surface of the suction cup is lower than the floating objects floating on the surface of the coolant, the floating objects will flow over the upper end surface and into the suction cup, but if the upper end surface of the suction cup is higher than the floating objects floating on the surface of the coolant, the floating objects will not be able to flow into the suction cup. In addition, in the first invention, when the air cylinder is operated with the float suction floating on the surface of the coolant in the coolant tank, the suction cup moves up and down as the piston rod moves forward or backward.

[0012] Therefore, if the stroke of the piston rod is adjusted in advance so that when the piston rod is fully advanced, the upper end surface of the suction cup is lower than the floating matter floating on the surface of the coolant, and when the piston rod is fully retracted, the upper end surface of the suction cup is higher than the floating matter, and by operating the air cylinder so that the piston rod repeatedly advances and retreats, the suction cup will repeatedly descend to a certain depth and then rise to a certain height, and each time a certain amount of the floating matter will flow into the suction cup. This stabilizes the amount of floating matter that is collected from the coolant tank and then supplied to the floating matter separation tank via the floating matter suction pipe.

[0013] In this way, in the first invention, a certain amount of floating matter is recovered from the coolant tank and supplied to the floating matter separation tank, which has the effect of separating the floating matter from the coolant in a stably state. In addition, because the first invention is structured to move the suction cup up and down using an air cylinder, unlike the case of using an electric cylinder, there is no need to install a power supply or electric cord near the coolant tank. Therefore, with the first invention, there is no risk of accidents such as short circuits or electric shocks even if the coolant is water-soluble.

[0014] A second invention is characterized in that in the first invention, a pneumatic circuit is provided that controls the operation of the air cylinder so that the piston rod repeatedly moves forward and backward cyclically. In the second invention, the stroke of the piston rod is adjusted in advance so that when the piston rod is fully advanced, the upper end surface of the suction cup is lower than the floating objects floating on the surface of the coolant, and when the piston rod is fully retracted, the upper end surface of the suction cup is higher than the floating objects.After that, when the pneumatic circuit is operated with the float suction floating on the surface of the coolant stored in the coolant tank, the action of the first invention, in which a certain amount of floating objects flows into the suction cup, is repeated at a specified period.

[0015] A third invention is the air operated valve according to the second invention, further comprising a first air operated valve having a first pilot port and a spring and supplied with compressed air via a first flow path; a second air operated valve having a second pilot port and a third pilot port and connected to a first branch flow path branching off from the first flow path; second and third flow paths connecting the second air operated valve to a first cylinder port and a second cylinder port of an air cylinder, respectively; a second branch flow path connecting the third flow path to the first pilot port; a first air chamber and a second air chamber connected to the first air operated valve via a fourth flow path and a fifth flow path, respectively; a sixth flow path connecting the second pilot port and the first air chamber and a seventh flow path connecting the third pilot port and the second air chamber; and a first pressure control valve and a second pressure control valve interposed in the sixth flow path and the seventh flow path, When a first pilot pressure is applied to the first pilot port, the operating valve switches from a first state in which the first flow path and the fourth flow path are connected and the compressed air in the fifth flow path is discharged to the atmosphere to a second state in which the first flow path and the fifth flow path are connected and the compressed air in the fourth flow path is discharged to the atmosphere, whereas when the first pilot pressure is no longer applied to the first pilot port, the operating valve switches from the second state to the first state by the biasing force of the spring, and the second air operating valve The rate valve is characterized in that, when a second pilot pressure is applied to the second pilot port, it switches from a third state in which the first branch flow path and the second flow path are connected and the compressed air in the third flow path and the second branch flow path is released into the atmosphere to a fourth state in which the first branch flow path and the third flow path are connected and the compressed air in the second flow path is released into the atmosphere, whereas, when a third pilot pressure is applied to the third pilot port, it switches from the fourth state to the third state. In addition, the first to seventh flow paths, as well as the first and second branch flow paths in the third invention, correspond to the air tubes 33a, 33d, 33e, 33b, 33c, 33f, and 33g, as well as the first and second branch tubes 34a and 34b, respectively, which will be described later as Example 1 in the form for implementing the invention.

[0016] In the third invention, when the head side port and rod side port of the air cylinder are the first cylinder port and the second cylinder port, and the first air operated valve and the second air operated valve are in the first state and the third state, respectively, compressed air supplied to the second air operated valve via the first flow path and the first branch flow path is supplied to the head side port of the air cylinder through the second flow path, so that the piston rod of the air cylinder moves forward and the compressed air discharged from the rod side port is supplied to the second air operated valve via the third flow path and then released into the atmosphere.

[0017] On the other hand, the compressed air supplied to the first air operated valve from the first flow path flows into the first air chamber through the fourth flow path. When the pressure in the first air chamber rises and reaches a value indicating a preset pressure (pilot pressure) for the first pressure control valve, the compressed air flows out of the first air chamber and is supplied to the second pilot port of the second air operated valve. Then, this compressed air acts as a second pilot pressure on the second air operated valve, and as a result, the second air operated valve switches from the third state to the fourth state.

[0018] When the second air operated valve is in the fourth state, the first branch flow path and the third flow path are connected in the second air operated valve, so that the compressed air supplied from the first flow path to the first branch flow path is supplied to the rod side port of the air cylinder through the third flow path. As a result, the piston rod retracts, and the compressed air discharged from the head side port is supplied to the second air operated valve through the second flow path and then released into the atmosphere. In addition, a part of the compressed air supplied to the third flow path is supplied to the first pilot port of the first air operated valve through the second branch flow path. Then, the compressed air supplied to the first pilot port acts as the first pilot pressure, and the first air operated valve switches from the first state to the second state.

[0019] When the first air operated valve is in the second state, the first flow path and the fifth flow path are connected in the first air operated valve, so that the compressed air supplied to the first flow path flows through the fifth flow path into the second air chamber. When the pressure in the second air chamber rises and reaches a value indicating a pressure preset for the second pressure control valve, the compressed air flows out of the second air chamber and is supplied to the third pilot port of the second air operated valve. Then, this compressed air acts as a third pilot pressure on the second air operated valve, and as a result, the second air operated valve switches from the fourth state to the third state.

[0020] When the second air operated valve is in the third state, the first branch passage and the second passage are connected in the second air operated valve. Therefore, the compressed air supplied from the first passage to the first branch passage passes through the second passage and is supplied to the head side port of the air cylinder, causing the piston rod to move forward again. The compressed air discharged from the rod side port is supplied to the second air operated valve through the third passage and then released into the atmosphere. On the other hand, since compressed air is no longer supplied from the first flow path to the third flow path and the second branch flow path, the first pilot pressure is no longer applied to the first pilot port, and as a result, the first air operated valve switches from the second state to the first state due to the biasing force of the spring, and the pneumatic circuit returns to its initial state.

[0021] Thus, in addition to the functions of the second invention, the third invention has the function that the piston rod of the air cylinder repeats forward and backward movement at a predetermined cycle by supplying compressed air to the pneumatic circuit, and has the function that the timing of the piston rod moving forward and backward changes individually by changing the set values ​​of the pilot pressures in the first pressure control valve and the second pressure control valve.

[0022] In the above description of the pneumatic circuit, the head side port and rod side port of the air cylinder are respectively referred to as the first cylinder port and the second cylinder port, but even if the head side port and rod side port are respectively referred to as the second cylinder port and the first cylinder port, the action of the piston rod of the air cylinder repeating forward and backward movements at a predetermined cycle is similarly exerted. However, when the set values ​​of the pilot pressures in the first pressure control valve and the second pressure control valve are changed, respectively, the timing at which the piston rod advances and the timing at which it retracts change individually.

[0023] A fourth invention, in the second invention, includes an air operated valve having a pilot port and a spring, and to which compressed air is supplied via a first flow path, a second flow path and a third flow path respectively connecting the air operated valve to a first cylinder port and a second cylinder port of the air cylinder, an air chamber connected to a branch flow path branching off from the second flow path, a fourth flow path connecting the air chamber and the pilot port, and a pressure control valve interposed in the fourth flow path, wherein when pilot pressure acts on the pilot port, the air operated valve switches from a first state in which the first flow path and the second flow path are communicated and the compressed air in the third flow path is released into the atmosphere to a second state in which the first flow path and the third flow path are communicated and the compressed air in the second flow path and the branch flow path is released into the atmosphere, whereas when pilot pressure is no longer acting on the pilot port, the air operated valve switches from the second state to the first state by the biasing force of the spring. The first to fourth flow paths and the branch flow paths in the fourth invention correspond to air tubes 36a, 36b, 36c, 36d and branch air tube 37, which will be described later as Example 2 in the form for carrying out the invention, respectively.

[0024] In the fourth invention, when the head side port and rod side port of the air cylinder are the first cylinder port and the second cylinder port, respectively, and the air operated valve is in the first state, a portion of the compressed air supplied from the first flow path through the air operated valve to the second flow path is supplied to the head side port of the air cylinder through the second flow path. Therefore, as the piston rod of the air cylinder advances, the compressed air discharged from the rod side port is supplied to the air operated valve via the third flow path and then released into the atmosphere. Meanwhile, the remainder of the compressed air supplied from the first flow path to the second flow path flows into the air chamber through the branch flow path. When the pressure in the air chamber rises and reaches a value indicating a preset pressure (pilot pressure) for the pressure control valve, the compressed air flows out of the air chamber and is supplied to the pilot port of the air operated valve. This compressed air then acts as the pilot pressure, switching the air operated valve from the first state to the second state.

[0025] When the air operated valve is in the second state, the first and third flow paths are connected in the air operated valve, so that the compressed air supplied to the first flow path passes through the third flow path and is supplied to the rod side port of the air cylinder. As a result, the piston rod retracts, and the compressed air discharged from the head side port is supplied to the air operated valve via the second flow path and then released into the atmosphere. In addition, compressed air is no longer supplied to the air chamber from the branch flow path, and pilot pressure is no longer acting on the pilot port, so the air-operated valve switches from the second state to the first state due to the biasing force of the spring, and the pneumatic circuit returns to its initial state.

[0026] Thus, in addition to the functions of the second invention, the fourth invention has the function that the piston rod of the air cylinder repeats forward and backward movement at a predetermined cycle by supplying compressed air to the pneumatic circuit, and the speed at which the piston rod moves backward changes when the set value of the pilot pressure in the pressure control valve is changed. In the above description of the pneumatic circuit, the head side port and rod side port of the air cylinder are referred to as the first cylinder port and the second cylinder port, respectively, but even if the head side port and rod side port are referred to as the second cylinder port and the first cylinder port, respectively, the piston rod of the air cylinder will similarly repeat forward and backward movements at a predetermined cycle. However, when the set value of the pilot pressure in the pressure control valve is changed, the timing at which the piston rod advances changes, not the timing at which the piston rod retreats.

[0027] The fifth invention is characterized in that, in the first or second invention, a guide pin is provided that is arranged parallel to the moving direction of the piston rod and has an upper end fixed to the connecting plate, and a guide portion that guides the guide pin parallel to the moving direction of the piston rod is provided in the suction cup. In float suction, the suction cup to which the tip of the piston rod is connected floats on the surface of the coolant and is prone to swinging. Therefore, if a lateral force (approximately perpendicular to the direction of movement of the piston rod) is applied from the suction cup to the tip of the piston rod as the suction cup swings, the piston rod may be damaged. However, in the fifth invention, the suction cup is guided in a direction parallel to the direction of movement of the piston rod by the guide pin, so that even if the suction cup swings, the lateral force is unlikely to be applied from the suction cup to the tip of the piston rod.

[0028] The sixth invention is characterized in that, in the first or second invention, the piston rod is provided with a rod-shaped body whose upper end is connected to a tip end and whose lower end is connected to a suction cup. In the sixth invention, in addition to the effect of the first or second invention, the use of rod-shaped bodies of different lengths has the effect that the distance from the tip of the piston rod to the suction cup changes.

[0029] The seventh invention is characterized in that, in the sixth invention, the rod-shaped body is provided with an anti-rotation nut having a female thread on its inner surface which screws into a male thread on the outer surface of the tip of the piston rod, and the rod-shaped body is a cylindrical suspension rod having a female thread on its inner surface which screws into the male thread of the piston rod, the tip of the piston rod is screwed into an upper end of the suspension rod, and the anti-rotation nut is installed at the upper end of the suspension rod with the tip of the piston rod screwed into it. In the seventh invention, when the suspension rod is rotated relative to the piston rod of the air cylinder, the distance from the suction cup to which the lower end of the suspension rod is connected to the connecting plate on which the air cylinder is installed changes. When the float suction is installed in the coolant tank, the float floating on the surface of the coolant is connected to the connecting plate, so the distance from the surface of the coolant to the connecting plate is kept approximately constant. Therefore, when the distance from the suction cup to the connecting plate changes, the height of the upper end surface of the suction cup relative to the surface of the coolant changes. That is, in the seventh invention, in addition to the function of the sixth invention, when the suspension rod is rotated relative to the piston rod with the float suction installed in the coolant tank, the height of the upper end face of the suction cup relative to the coolant level changes. Also, the anti-rotation nut prevents the piston rod from loosening relative to the suspension rod.

[0030] The eighth invention is characterized in that, in the seventh invention, it comprises a cylindrical body loosely inserted into a through hole provided in the bottom surface of the suction cup, a bolt inserted into the cylindrical body from below the suction cup, and a washer installed between the cylindrical body and the suspension rod with the bolt inserted, and the lower end of the suspension rod is fixed to the suction cup by the bolt. When the moving direction of the suction cup is specified, the central axis of the piston rod and the central axis of the suspension rod are aligned, but the moving direction of the piston rod may not be aligned completely with the moving direction of the suction cup. In this case, the bolt inserted into the through hole so that its central axis is parallel to the moving direction of the suction cup receives a force from the suspension rod, which moves together with the piston rod, in a direction inclined with respect to the central axis. In contrast, in the eighth invention, the cylinder provides a clearance between the bolt and the inner circumferential surface of the through hole of the suction cup, and the cylinder and the suspension rod do not come into direct contact with each other due to the washer. In this case, since a large frictional force is unlikely to be generated between the bolt and the suspension rod and the suction cup, the eighth invention has the same effect as the seventh invention, and also has the effect of mitigating the effect of the force applied to the bolt on the inner circumferential surface of the through hole of the suction cup.

[0031] A ninth invention is characterized in that, in the seventh invention, the piston rod and the suspension rod are connected via a floating joint. In the ninth invention, when the direction of movement of the suction cup is specified and coincides with the central axis of the suspension rod, if the direction of movement of the piston rod is inclined with respect to the direction of movement of the suction cup, the direction of movement of the piston rod will be inclined with respect to the central axis of the suspension rod. However, since the floating joint has a function of preventing a force other than that parallel to the central axis of the suspension rod from being applied from the piston rod to the suspension rod, the ninth invention has, in addition to the function of the seventh invention, the function that there is no risk of the bolt fixing the lower end of the suspension rod to the bottom surface of the suction cup receiving a force in a direction inclined with respect to the central axis from the piston rod via the suspension rod.

[0032] The tenth invention is characterized in that, in the first invention, the floated matter separation tank comprises a separation chamber having a floated matter supply port and a floated matter discharge port, and a clear liquid storage chamber having a coolant discharge port, and the separation chamber and the clear liquid storage chamber are connected at the bottom of the floated matter separation tank. In the tenth invention, the floating matter is supplied together with the coolant from the floating matter supply port to the floating matter separation tank, and the floating matter separated from the coolant in the separation chamber overflows from the floating matter discharge port. At this time, the floating matter contains almost no coolant. That is, in addition to the function of the first invention, the tenth invention has the function that the coolant is difficult to discharge from the floating matter discharge port.

[0033] In addition, since the floating matter has a smaller specific gravity than the coolant, and the floating matter supplied to the separation chamber rises in the coolant and gathers near the liquid surface, the separation of the floating matter and the coolant is promoted in the separation chamber as it moves away from the coolant liquid surface. As a result, at the bottom of the separation chamber, a portion of the coolant (clear liquid) that has completely separated from the floating matter moves to the clear liquid storage chamber and is then discharged from the coolant discharge port to the outside of the floating matter separation tank. In this way, in the tenth invention, a space (separation chamber) to which the floating matter is supplied and a space (clean liquid storage chamber) in which the coolant discharged from the floating matter separation tank exists are provided within the floating matter separation tank, so there is no risk of the floating matter being mistakenly discharged from the coolant discharge outlet. Effect of the Invention

[0034] In the first invention, a certain amount of floating matter is collected from the coolant tank, and a small amount of floating matter is stably supplied to the floating matter separation tank. This lengthens the residence time of the floating matter in the floating matter separation tank, making a large floating matter separation tank unnecessary. Therefore, according to the first invention, it is possible to save space for installing the floating matter separation tank. Furthermore, according to the first aspect of the present invention, the floating matter is separated from the coolant in a stable state in the floating matter separating tank, so that the floating matter can be efficiently collected from the coolant. Furthermore, the first invention can be used safely because there is no risk of accidents such as short circuits or electric shock even if the coolant is water-soluble.

[0035] In the second invention, a certain amount of floating matter recovered from the coolant tank is repeatedly supplied to the floating matter separation tank at a predetermined cycle, thereby further enhancing the effect of the first invention, that is, the floating matter can be efficiently recovered from the coolant.

[0036] According to the third invention, the piston rod of the air cylinder can be caused to repeatedly move forward and backward at a predetermined cycle simply by supplying compressed air to the pneumatic circuit, thereby ensuring the effect of the second invention, that is, the floating objects can be collected from the coolant more efficiently than in the case of the first invention.

[0037] In the fourth aspect of the invention, the structure of the pneumatic circuit is simpler than that of the third aspect of the invention, but the same effects as those of the third aspect of the invention can be expected. Therefore, according to the fourth aspect of the invention, it is possible to reduce manufacturing costs compared to the third aspect of the invention.

[0038] According to the fifth invention, when the float suction is installed in the coolant tank, even if the suction cup swings, a lateral force is unlikely to be applied to the tip of the piston rod from the suction cup, so in addition to the effects of the first or second invention, the effect of making the air cylinder less likely to break down can be expected.

[0039] According to the sixth invention, in addition to the effects of the first or second invention, the effect of being able to adjust the distance between the air cylinder and the suction cup by changing the distance from the tip of the piston rod to the suction cup is achieved.

[0040] According to the seventh invention, in addition to the effect of the sixth invention, the seventh invention has the effect that the height of the upper end surface of the suction cup relative to the liquid surface of the coolant can be easily adjusted by the simple operation of rotating the suspension rod.

[0041] According to the eighth invention, the direction of movement of the suction cup is specified, and even if its direction of movement does not completely coincide with the direction of movement of the suspension rod, large frictional forces are unlikely to occur between the bolt and the suspension rod and the bottom surface of the suction cup, thereby achieving the effect of preventing the suction cup from being destroyed by the force applied to the bolt from the suspension rod in addition to the effect of the seventh invention.

[0042] According to the ninth invention, in addition to the effects of the seventh invention, the moving direction of the suction cup is defined, and even when the moving direction of the suction cup does not completely coincide with the moving direction of the suspension rod, it is possible to prevent damage to the through hole of the suction cup, and it is possible to prevent the piston rod and the suspension rod from being damaged or deformed by receiving forces other than the moving direction and the central axis direction.

[0043] In the tenth invention, not only is it difficult for the coolant to be discharged when the floating matter is discharged from the floating matter discharge port, but also it is difficult for the floating matter to be discharged when the coolant is discharged from the coolant discharge port. Therefore, the ratio of the floating matter separated from the coolant is high. Therefore, by using the eighth invention, it is possible to efficiently recover the floating matter from the coolant.

Brief Description of the Drawings

[0044] [Figure 1] (a) is a schematic diagram of Example 1 of the floating matter recovery device according to an embodiment of the present invention, and (b) is a plan view of the scum separation tank shown in FIG. (a). [Diagram 2] (a) and (b) are respectively a plan view and a left side view of the partition plate shown in FIGS. 1(a) and 1(b), and (c) is a cross-sectional view taken along the arrow B-B in FIG. 1(b). [Diagram 3] It is a view taken in the direction of arrow A in FIG. 1(a). [Figure 4] (a) and (b) are respectively a front view and a plan view of the float suction shown in FIG. 1(a). [Diagram 5] (a) is a plan view of the suction cup shown in FIGS. 4(a) and 4(b), and (b) is a cross-sectional view taken along the arrow C-C in FIG. 4(b). [Figure 6] (a) and (b) are respectively enlarged views of parts D and E in FIG. 5(b), and (c) and (d) are respectively views showing modified examples of FIGS. (a) and (b). [Figure 7] (a) and (b) are respectively a plan view and a front view of a modified example of the suction cup shown in FIG. 5(a). [Figure 8] 5(a) and (b) are views showing the suction cup in FIG. 5(b) in a raised state and a lowered state, respectively. [Figure 9] FIG. 4(a) is a block diagram showing the configuration of a pneumatic circuit that controls the operation of the air cylinder shown in FIG. 4(a), and FIG. 4(b) is a diagram showing the state in which compressed air is supplied to the pneumatic circuit in FIG. 4(a). [Figure 10] 9(a) is a diagram showing a state in which the first air operated valve in FIG. 9(b) has been switched, and FIG. 9(b) is a diagram showing a state in which the second air operated valve in FIG. 9(a) has been switched. [Figure 11] 10(a) is a diagram showing a state in which the first air operated valve in FIG. 10(b) has been switched, and (b) is a diagram showing a state in which the second air operated valve in FIG. 10(a) has been switched. [Figure 12] 10 is a flowchart for explaining the operation of the pneumatic circuit shown in FIG. [Figure 13] FIG. 1(a) is a block diagram showing the configuration of an air pressure circuit in a second embodiment of a floating matter recovery device according to the present invention, and FIG. 1(b) is a diagram showing the state in which compressed air is supplied to the air pressure circuit in FIG. [Figure 14] FIG. 13(a) is a diagram showing how pilot pressure acts on the pilot port of the air operated valve in FIG. 13(b), and FIG. 13(b) is a diagram showing the state after the air operated valve in FIG. 13(a) has been switched. [Figure 15] 14 is a flowchart for explaining the operation of the pneumatic circuit shown in FIG. 13(a). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045] The floating matter recovery device of the present invention will be specifically described with reference to Figs. 1 to 15. In the following description, expressions such as "above", "below", "upper part", and "lower part" are used on the assumption that the floating matter recovery device is actually used, that is, that the scum separation tank and the coolant tank are placed on a horizontal surface. In addition, as an embodiment, a case where scum floating on the liquid surface of the coolant is recovered is described, but the floating matter recovery device of the present invention can recover not only scum but also floating matters such as floating oil. Therefore, the following description can be made even if "scum" is replaced with "floating oil" or "floating matter". In addition, "scum separation tank", "scum discharge port", "scum supply port", "scum discharge chute", "scum suction pipe", and "scum supply pipe" correspond to subordinate concepts of "floating matter separation tank", "floating matter discharge port", "floating matter supply port", "floating matter discharge chute", "floating matter suction pipe", and "floating matter supply pipe", respectively. Furthermore, in the following description, in order to clarify which pilot port the pilot pressure acts on in the first air operated valve 26 and the second air operated valve 27, the pilot pressures acting on the first pilot port 26a, the second pilot port 27a and the third pilot port 27b are referred to as the first pilot pressure, the second pilot pressure and the third pilot pressure, respectively, for the sake of convenience. EXAMPLES

[0046] Fig. 1(a) is a diagram showing a schematic configuration of a floating matter recovery device 1 according to an embodiment of the present invention, and Fig. 1(b) is a plan view of the scum separation tank 2 shown in Fig. 1(a). Figs. 2(a) and 2(b) are a plan view and a left side view, respectively, of a partition plate 12, and Fig. 2(c) is a cross-sectional view taken along line BB in Fig. 1(b). Fig. 3 is a view taken along the direction of the arrow A in Fig. 1(a). In addition, the partition plate 12 is not shown in FIG. 2(c), and in FIG. 3, only the scum separating tank 2 is shown, and the L-shaped pipe 3b and the straight pipe 3f are not shown.

[0047] As shown in Figures 1(a) and 1(b), the floating matter recovery device 1 of the present invention comprises a scum separation tank 2 which is open at the top, a coolant tank 4 in which coolant 11b is stored together with scum 11a, and a float suction 5 installed inside the coolant tank 4. The scum separation tank 2 is provided with a scum discharge port 2a at the top, and a scum supply port 2b and a coolant discharge port 2c are provided at a lower position than the scum discharge port 2a. A coolant discharge pipe 3 is connected to the coolant discharge port 2c, and a scum supply pipe 13 is connected to the scum supply port 2b. The scum discharge outlet 2a is composed of an opening 2i (see Figure 3) provided at the upper end of the side plate 2d and a scum discharge chute 2j (see Figure 1(a)) extending diagonally downward from the lower edge 2k (see Figure 1(b)) of this opening 2i.

[0048] One end of a scum suction pipe 6 is connected to a suction port 5a (see FIG. 5(a)) of the float suction 5, which is floated on the liquid surface 11c of the coolant 11b, so that the scum 11a floating on the liquid surface 11c of the coolant 11b flows into the float suction pipe 6. The scum suction pipe 6, which may be a metal or plastic hose or a flexible hose that is easily deformed, is fitted with a filter 7 and an air-driven diaphragm pump 8, and the other end of the scum suction pipe 6 is connected to the scum supply port 2b of the scum separation tank 2.

[0049] The interior of the scum separation tank 2 is divided by a partition plate 12, which has a liquid passage port 12a and is fixed to the inner surface of the side plate 2d by an attachment plate 10 that is L-shaped in plan view, into two spaces: a separation chamber 2e having a scum supply port 2b in the bottom plate 2g, and a clear liquid storage chamber 2f having a coolant discharge port 2c in the side plate 2d. Although not an essential component of the floating matter recovery device 1, a scum tank 9 for storing the scum 11a discharged from the scum separation tank 2 is provided below the scum discharge port 2a.

[0050] The scum supply pipe 13 is composed of a connecting pipe 13a which is inserted into the scum supply port 2b of the scum separation tank 2, a straight pipe 13b which is installed parallel to the depth direction of the scum separation tank 2 and has its lower end connected to the connecting pipe 13a and its upper end connected to one end of an L-shaped pipe 13c, and a T-shaped pipe 13d which is connected to the other end of the L-shaped pipe 13c. The coolant discharge pipe 3 is composed of an L-shaped pipe 3a having one end inserted into the coolant discharge port 2c of the scum separation tank 2, a liquid level adjustment socket 3c attached to the other end of the L-shaped pipe 3a, an L-shaped pipe 3b having one end connected to the L-shaped pipe 3a, and a straight pipe 3f having its upper end connected to the other end of the L-shaped pipe 3b and installed parallel to the depth direction of the scum separation tank 2.

[0051] As shown in Figures 2(a) and 2(b), the partition plate 12 is formed by bending a flat plate material having a rectangular shape in plan view twice, so that two flat plate portions 14a and 14b arranged approximately parallel to each other and a connecting portion 14c connecting the two flat plate portions 14a and 14b are formed so that both of them have a rectangular shape in plan view. In addition, screw insertion holes 12b used when the partition plate 12 is fixed to the side plate 2d of the scum separation tank 2 by using the mounting plate 10 are provided at the four corners of the partition plate 12, and the above-mentioned liquid passage port 12a is provided in the flat plate portion 14b. In other words, the separation chamber 2e and the clear liquid storage chamber 2f are connected by the liquid passage port 12a provided in the flat plate portion 14b arranged at the lower part of the scum separation tank 2. Instead of providing the liquid passage port 12a in the flat plate portion 14b of the partition plate 12, a gap may be provided between the bottom plate 2g and the flat plate portion 14b of the scum separation tank 2, and the separation chamber 2e and the clear liquid storage chamber 2f may be connected by this gap. Also, instead of attaching the partition plate 12 to the scum separation tank 2, a partition wall may be provided inside the scum separation tank 2, and the separation chamber 2e and the clear liquid storage chamber 2f may be formed inside the scum separation tank 2 by separating them with this partition wall.

[0052] Furthermore, FIG. 1(a) shows a structure in which the separation chamber 2e and the clear liquid storage chamber 2f are connected at the bottom of the scum separation tank 2 by a liquid passage port 12a of a partition plate 12 provided near the bottom plate 2g of the scum separation tank 2. However, since the liquid passage port 12a only needs to be provided at the bottom of the scum separation tank 2, the location at which the liquid passage port 12a is provided is not limited to near the bottom plate 2g of the scum separation tank 2 and can be changed as appropriate. However, if the liquid passage port 12a is provided near the bottom plate 2g of the scum separation tank 2, the separation chamber 2e and the clear liquid storage chamber 2f will be structured to be connected at the bottom of the scum separation tank 2, so that it is expected that only the coolant 11b that has been completely separated from the scum 11a and stored at the bottom of the scum separation tank 2 will move from the separation chamber 2e to the clear liquid storage chamber 2f through the liquid passage port 12a.

[0053] As shown in Fig. 2(c), the liquid level adjustment socket 3c is a cylinder having a female thread formed on its inner circumferential surface, and is installed inside the scum separation tank 2 so that the cylindrical axis is parallel to the vertical direction. One end of an L-shaped pipe 3a having a male thread formed on its outer circumferential surface to be screwed into the female thread is screwed into a lower end 3d of the liquid level adjustment socket 3c. The L-shaped pipe 3a is fixed to the side plate 2d of the scum separation tank 2 so that the other end is inserted into the coolant discharge port 2c. Therefore, when the liquid level adjustment socket 3c is rotated relative to the L-shaped pipe 3a, the liquid level adjustment socket 3c rises or falls relative to the scum separation tank 2.

[0054] The coolant 11b that has exceeded the upper end 3e of the level adjustment socket 3c in the clear liquid storage chamber 2f flows into the level adjustment socket 3c as shown by the arrow in Fig. 2(c), and then passes through the L-shaped pipe 3a, the L-shaped pipe 3b, and the straight pipe 3f to be discharged outside the scum separation tank 2. The coolant 11b in the separation chamber 2e moves to the clear liquid storage chamber 2f through the liquid passage port 12a of the partition plate 12 until the coolant 11b and the liquid level 11c shown in Fig. 2(c) become the same. That is, when the level adjustment socket 3c is rotated relative to the L-shaped pipe 3a, the height of the liquid level 11c of the coolant 11b changes. The adjustment range of the liquid level of the coolant 11b in the scum separation tank 2 may be about 3 to 4 mm when the scum 11a forms a thin layer such as a lubricating oil with good fluidity, but needs to be about 5 to 8 mm when the scum 11a forms a thick granular or foamy layer with poor fluidity. In other words, it is desirable to set the adjustment range of the liquid level of the coolant 11b according to the shape and fluidity of the scum 11a.

[0055] In the scum separation tank 2, when the height of the liquid surface 11c of the coolant 11b exceeds the level 2h (see FIG. 1(a)) of the lower edge 2k of the scum discharge port 2a, the coolant 11b is discharged from the scum discharge port 2a together with the scum 11a. However, in the floating matter recovery device 1, the liquid surface level adjustment socket 3c is rotated relative to the L-shaped pipe 3a to adjust the height of the liquid surface 11c of the coolant 11b and set it lower than the above-mentioned level 2h, thereby making it possible to minimize the amount of the coolant 11b discharged from the scum discharge port 2a together with the scum 11a. In this way, in the floating matter recovery device 1, the height of the liquid surface 11c of the coolant 11b can be adjusted by the simple operation of rotating the liquid surface level adjustment socket 3c relative to the L-shaped tube 3a, so that the amount of coolant 11b discharged together with the scum 11a from the scum discharge port 2a can be reduced, thereby enabling high-purity scum 11a to be discharged from the scum separation tank 2.

[0056] In the floating matter recovery device 1 having the above-mentioned structure, a part of the scum 11a floating on the liquid surface 11c of the coolant 11b stored in the coolant tank 4 is collected by the float suction 5 and supplied from the scum supply port 2b to the scum separation tank 2 by the action of the air-driven diaphragm pump 8 interposed in the scum suction pipe 6. When collecting the scum 11a by the float suction 5, the coolant 11b is also collected together with it, but as will be described later, the float suction 5 is structured to keep the amount of coolant 11b collected together with the scum 11a to a minimum.

[0057] The scum 11a and coolant 11b supplied from the coolant tank 4 to the connecting pipe 13a of the scum supply pipe 13 installed in the scum supply port 2b of the scum separation tank 2 rise inside the straight pipe 13b, then flow through the L-shaped pipe 13c into the inside of the T-shaped pipe 13d. Then, the air contained in the scum 11a is released into the atmosphere from the upper end of the T-shaped pipe 13d, and the remaining scum 11a and coolant 11b are discharged from the lower end of the T-shaped pipe 13d. At this time, since the T-shaped pipe 13d is installed so that its lower end is higher than the above-mentioned level 2h, the scum 11a and coolant 11b discharged from the T-shaped pipe 13d are supplied quietly from above to the coolant 11b already stored in the scum separation tank 2 without causing any significant rippling of the liquid surface 11c (see Figure 2(c)).

[0058] When the scum 11a is discharged from the scum discharge port 2a in a foamed state, the amount of coolant 11b contained in the scum 11a is small, but if the liquid surface 11c of the coolant 11b is greatly wavy, not only the scum 11a in a foamed state but also a large amount of coolant 11b may be discharged from the scum discharge port 2a together with the scum 11a. However, the floating matter recovery device 1 is structured such that the scum 11a and the coolant 11b are gently supplied from above to the coolant 11b already stored in the scum separation tank 2 so that the liquid surface 11c does not greatly wavy, as described above. That is, in the floating matter recovery device 1, the liquid surface 11c of the coolant 11b does not greatly wavy when the scum 11a is supplied to the scum separation tank 2, so that the amount of coolant 11b discharged from the scum discharge port 2a together with the scum 11a is small.

[0059] The scum 11a supplied together with the coolant 11b to the separation chamber 2e of the scum separation tank 2 has a smaller specific gravity than the coolant 11b, and therefore rises up in the coolant 11b. At this time, since the connecting portion 14c of the partition plate 12 is inclined, even if the rising scum 11a comes into contact with the partition plate 12, the movement of the scum 11a is not easily hindered. Furthermore, as shown in FIG. 3, the width of separation chamber 2e is narrower at the upper part than at the lower part, so that scum 11a that reaches liquid surface 11c of coolant 11b is likely to form a thick layer of bubbles thereon.

[0060] When the layer of foam formed by the scum 11a is thick, it becomes easy to set the height of the liquid surface 11c of the coolant 11b lower than the level 2h of the lower edge 2k of the scum discharge port 2a. Therefore, according to the floating matter recovery device 1 that can easily adjust the height of the liquid surface 11c of the coolant 11b using the liquid surface level adjustment socket 3c, it is possible to discharge high-purity scum 11a from the scum separation tank 2. Furthermore, the scum separation tank 2 has a wide lower portion of the separation chamber 2e, and has a structure in which the scum 11a and the coolant 11b tend to remain for a long time, so that the separation of the scum 11a and the coolant 11b tends to proceed easily.

[0061] In the clear liquid storage chamber 2f of the scum separation tank 2, a portion of the coolant 11b (hereinafter referred to as clear liquid) that has been completely separated from the scum 11a moves toward the clear liquid storage chamber 2f through a liquid passage port 12a (see Figure 1(a)) provided near the bottom plate 2g. The coolant 11b (clear liquid) that has moved to the clear liquid storage chamber 2f is then discharged through the coolant discharge pipe 3 to the outside of the scum separation tank 2 from the coolant discharge port 2c (see Figure 2(c)), and then returned to the coolant tank 4 as indicated by the dashed arrow in Figure 1(a).

[0062] Thus, in the floating matter recovery device 1, the inside of the scum separation tank 2 is divided by the partition plate 12 into a separation chamber 2e (a space required for separating the scum 11a supplied from the scum supply port 2b together with the coolant 11b from the coolant 11b) and a clear liquid storage chamber 2f (a space for storing the coolant 11b (clear liquid) completely separated from the scum 11a). Therefore, there is no risk that the scum 11a supplied to the scum separation tank 2 will be discharged as it is from the coolant discharge port 2c.

[0063] That is, in the floating matter recovery device 1, not only is it difficult for the coolant 11b to be discharged when the scum 11a is discharged from the scum discharge port 2a, but there is also no risk of the scum 11a being discharged together with the coolant 11b when the coolant 11b is discharged from the coolant discharge port 2c. Therefore, in the floating matter recovery device 1, high-purity scum 11a separated from the coolant 11b is discharged from the scum discharge port 2a. Therefore, by using the floating matter recovery device 1, it is possible to efficiently recover the scum 11a from the coolant 11b. In the floating matter recovery device 1, when the scum separation tank 2 is used for a long period of time, solid matter with a large specific gravity may settle to the bottom, so the scum separation tank 2 needs to be cleaned periodically. In this regard, the partition plate 12 is removably fixed to the side plate 2d of the scum separation tank 2 using screws or bolts, and can be easily removed when cleaning work is performed. Therefore, in the floating matter recovery device 1, cleaning work of the scum separation tank 2 can be easily performed.

[0064] Figures 4(a) and 4(b) are respectively a front view and a plan view of the float suction 5. Also, Figure 5(a) is a plan view of the suction cup 15 shown in Figures 4(a) and 4(b), and Figure 5(b) is a cross-sectional view taken along line CC in Figure 4(b). Furthermore, Figures 6(a) and 6(b) are respectively enlarged views of parts D and E in Figure 5(b), and Figures 6(c) and 6(d) are respectively views showing modified versions of Figures 6(a) and 6(b). In Fig. 5(b), only the suction cup 15 is shown in cross section, and the other components are shown in their external appearance. Also, in Fig. 6(c), unlike Fig. 6(a), the suspension rod 20 and the anti-rotation nut 21 are also shown in external appearance.

[0065] As shown in Figures 4(a) and 4(b), 5(a) and 5(b), and 6(a) and 6(b), the float suction 5 includes a suction cup 15 having a suction port 5a on a side surface 15b near a bottom surface 15a, a connecting plate 16 having three arm portions 16a, a float 18 connected to the tip of each of the three arm portions 16a on the bottom surface 16b side using a bolt 17a, an air cylinder 19 installed on the top surface 16c side of the connecting plate 16, a piston rod 19a having a male threaded portion at the tip and arranged to protrude from the bottom surface 16b through a through hole (not shown) provided in the connecting plate 16, and a suspension rod 20 consisting of a cylinder having a female threaded portion provided on the inner surface thereof that screws into the male threaded portion of the piston rod 19a. The suspension rod 20 is provided with an anti-rotation nut 21 into which the piston rod 19a is screwed when the suspension rod 20 is positioned at the upper end 20a thereof, a bolt 17b screwed into the lower end 20b thereof, a cylindrical collar 22a loosely inserted into a through hole 15c (see FIG. 6(b)) provided in the bottom surface 15a of the suction cup 15, a pair of washers 22b, 22b which are respectively positioned at both ends of the collar 22a and through which the bolt 17b communicates with the collar 22a, and three guide pins 23 whose upper ends 23a are fixed to the arm portion 16a and whose lower ends 23b are loosely inserted and slidably inserted into guide holes 15d (see FIG. 5(a)) provided in the suction cup 15 and which are parallel to the movement direction of the piston rod 19a. In order not to impede the movement of the guide pin 23 inserted in the guide hole 15d of the suction cup 15 in the vertical direction, a clearance must be provided between the inner peripheral surface of the guide hole 15d and the outer peripheral surface of the guide pin 23. However, this clearance is set to a size that prevents a large amount of coolant 11b from flowing into the inside of the suction cup 15.

[0066] In the float suction 5, the suction cup 15 to which the tip of the piston rod 19a is connected floats on the liquid surface 11c of the coolant 11b, making it prone to swinging. Therefore, if a lateral force (a direction substantially perpendicular to the direction of movement of the piston rod 19a) is applied to the tip of the piston rod 19a from the suction cup 15 as the suction cup 15 swings, the piston rod 19a may be damaged. However, in the float suction 5 having the above structure, the suction cup 15 is guided by the guide pin 23 in a direction parallel to the moving direction of the piston rod 19a, so that even if the suction cup 15 swings, a lateral force is unlikely to be applied to the tip of the piston rod 19a from the suction cup 15. Therefore, in the floating object recovery device 1, the air cylinder 19 is unlikely to break down.

[0067] In the float suction 5, the central axis of the piston rod 19a and the central axis of the suspension rod 20 are aligned, but the moving direction of the piston rod 19a may not completely match the moving direction of the suction cup 15 guided by the guide pin 23. In this case, the bolt 17b, which is inserted into the through hole 15c so that its central axis is parallel to the moving direction of the suction cup 15, receives a force from the suspension rod 20, which moves together with the piston rod 19a, in a direction inclined with respect to the central axis. In contrast, in the float suction 5 having the above structure, a clearance is provided by the collar 22a between the inner peripheral surface of the through hole 15c of the suction cup 15 and the bolt 17b, and the collar 22a and the suspension rod 20 are not directly contacted by the washer 22b installed between the lower end 20b (see FIG. 6(b)) of the suspension rod 20 and the bottom surface 15a of the suction cup 15. In this case, since a large frictional force is unlikely to occur between the bolt 17b and the suspension rod 20 and the bottom surface 15a of the suction cup 15, the effect of the force applied to the bolt 17b on the inner peripheral surface of the through hole 15c is mitigated. Therefore, even if the moving direction of the piston rod 19a does not completely coincide with the moving direction of the suction cup 15, the through hole 15c of the suction cup 15 will not be destroyed by the force applied from the suspension rod 20 to the bolt 17b.

[0068] Furthermore, when the suspension rod 20 is rotated relative to the piston rod 19a of the air cylinder 19, the distance from the suction cup 15 to which the lower end 20b of the suspension rod 20 is connected to the connecting plate 16 to which the air cylinder 19 is installed changes. When the float suction 5 is installed in the coolant tank 4, the float 18 floating on the liquid surface 11c of the coolant 11b is connected to the connecting plate 16, so the distance from the liquid surface 11c of the coolant 11b to the connecting plate 16 is kept approximately constant. Therefore, when the distance from the suction cup 15 to the connecting plate 16 changes, the height of the upper end surface 15e (see FIG. 5(b)) of the suction cup 15 relative to the liquid surface 11c of the coolant 11b changes. That is, in the float suction 5, the height of the upper end surface 15e of the suction cup 15 relative to the liquid surface 11c of the coolant 11b can be adjusted by rotating the suspension rod 20 relative to the piston rod 19a. The anti-rotation nut 21 has the function of preventing the piston rod 19a from loosening relative to the suspension rod 20.

[0069] Furthermore, if a suspension rod 20 of a different length is used, the distance from the tip of the piston rod 19a to the suction cup 15 changes, and in this case, the distance between the air cylinder 19 and the suction cup 15 changes. In other words, in the float suction 5 with the above structure, the distance between the air cylinder 19 and the suction cup 15 can be easily adjusted according to the size of the coolant tank 4. It is also possible to use a rod-shaped body instead of the suspension rod 20 to connect the piston rod 19a and the suction cup 15. Even in this case, the above-mentioned effect of being able to easily adjust the distance between the air cylinder 19 and the suction cup 15 by using rod-shaped bodies of different lengths can be similarly achieved.

[0070] The portions D and E in Fig. 5(b) are not limited to the structures shown in Fig. 6(a) and Fig. 6(b). For example, the connecting portion between the piston rod 19a and the suspension rod 20 and the connecting portion between the suction cup 15 and the suspension rod 20 may have the structures shown in Fig. 6(c) and Fig. 6(d). That is, instead of the collar 22a being loosely inserted into the through hole 15c of the suction cup 15 and the washer 22b being installed on the upper end of the collar 22a, the piston rod 19a and the suspension rod 20 may be connected via a floating joint 22c. The floating joint 22c has a function of preventing a force from being applied from the piston rod 19a to the suspension rod 20 in a direction other than that parallel to the central axis of the suspension rod 20.

[0071] In the float suction 5 having the above structure, the central axis of the bolt 17b, the central axis of the suspension rod 20, and the moving direction of the suction cup 15 are aligned, so if the moving direction of the piston rod 19a does not completely match the moving direction of the suction cup 15, the moving direction of the piston rod 19a will be tilted with respect to the central axis of the suspension rod 20. However, even in such a case, the action of the floating joint 22c causes the piston rod 19a to apply a force only in a direction parallel to the central axis of the suspension rod 20, so there is no risk that the bolt 17b will receive a force from the piston rod 19a through the suspension rod 20 in a direction tilted with respect to the central axis. Therefore, the through hole 15c of the suction cup 15 will not be damaged by the force applied to the bolt 17b. Furthermore, since the movement direction of piston rod 19a is inclined relative to the central axis of suspension rod 20, there is no risk of piston rod 19a being damaged or deformed by a force parallel to the movement direction, or of suspension rod 20 being damaged or deformed by a force in a direction other than parallel to the central axis.

[0072] Figures 7(a) and 7(b) are respectively a plan view and a front view of a suction cup 41 according to a modified example of the suction cup 15. Also, Figures 8(a) and 8(b) are respectively views showing the suction cup 15 in Figure 5(b) in a raised state and a lowered state. In FIG. 7(a), the portion of the upper end surface 15e of the suction cup 41 where the slits 41a are not provided is hatched to distinguish it from the portion where the slits 41a are provided. As shown in Figures 7(a) and 7(b), the suction cup 41 has a structure in which three slits 41a having a desired depth from the upper end surface 15e of the suction cup 15 and a desired width in the circumferential direction are provided at approximately equal intervals in the circumferential direction. If a float suction 5 equipped with a suction cup 41 having such a structure is installed in a coolant tank 4 instead of a suction cup 15, if the lowest part 41b of the slit 41a is even slightly lower than the height of the liquid surface 11c of the coolant 11b, the scum 11a will flow into the inside of the suction cup 41 through the slit 41a.

[0073] For example, when the distance between the float 18 and the suction cup 50 is short, if the suction cup 41 is positioned so that the overlap between the arm 16a and the slit 41a is minimized when viewed in plan, the float 18 will not interfere with the flow of scum 11a, and the scum 11a will flow smoothly into the inside of the suction cup 41. On the other hand, when the distance between the float 18 and the suction cup 41 is long and there is no risk of the float 18 interfering with the flow of scum 11a regardless of the positional relationship between the float 18 and the slit 41a, it is preferable to use, instead of the suction cup 41, the suction cup 15, which has a structure that allows scum 11a to flow in from all around.

[0074] In a floating matter recovery device 1 having such a structure, when the float suction 5 is floated on the liquid surface 11c of the coolant 11b stored in the coolant tank 4, the suction cup 15 moves downward as the piston rod 19a advances, and when the upper end surface 15e of the suction cup 15 becomes lower than the scum 11a floating on the liquid surface 11c of the coolant 11b, the scum 11a flows over the upper end surface 15e and into the inside of the suction cup 15 (see Figure 8(a)). On the other hand, when the suction cup 15 moves upward as the piston rod 19a retracts, and the upper end surface 15e of the suction cup 15 becomes higher than the scum 11a floating on the liquid level 11c of the coolant 11b, the scum 11a does not exceed the upper end surface 15e and flow into the inside of the suction cup 15 (see Figure 8(b)).

[0075] When the air cylinder 19 is operated with the float suction 5 floating on the liquid surface 11c of the coolant 11b, the suction cup 15 moves up and down as the piston rod 19a moves forward and backward. Therefore, if the stroke of the piston rod 19a is adjusted in advance so that the piston rod 19a is in the state shown in Figure 8(a) and Figure 8(b) when it is in the most advanced position and the most retracted position, the air cylinder 19 is operated so that the piston rod 19a repeats the advancement and retraction of the piston rod 19a, whereby the suction cup 15 repeats the phenomenon of descending to a certain depth and then rising to a certain height. Then, a certain amount of scum 11a flows into the suction cup 15 each time, so that the amount of scum 11a recovered from the coolant tank 4 and supplied to the scum separation tank 2 becomes stable. In this manner, in the floating matter recovery device 1, a certain amount of scum 11a is recovered from the coolant tank 4 and supplied to the scum separation tank 2, so that the scum 11a is separated from the coolant 11b in the scum separation tank 2 in a stable state.

[0076] The sinking depth of suction cup 15 (the depth to which suction cup 15 sinks from the state of Figure 8(a) to the state of Figure 8(b)) may be set according to the shape of scum 11a and the fluidity of coolant 11b, for example, to about 3 to 4 mm when coolant 11b is a lubricant with good fluidity and a thin layer is formed by scum 11a, or to about 5 to 8 mm when coolant 11b has poor fluidity and a thick granular or foamy layer is formed by scum 11a. It is also desirable to raise the suction cup 15 when the scum 11a has accumulated to about 80%, and to keep the air-driven diaphragm pump 8 running all the time, even when the suction cup 15 is rising or falling. In this way, the scum 11a, coolant 11b, and air are sucked in, and the inside of the suction cup 15 becomes completely empty. Therefore, by repeating this at the same cycle, the amount of scum 11a collected is kept constant.

[0077] When a certain amount of scum 11a is collected from the coolant tank 4, a small amount of scum 11a is stably supplied to the scum separation tank 2. This lengthens the residence time of the scum 11a in the scum separation tank 2, eliminating the need for a large scum separation tank 2. Therefore, according to this method, it is possible to save space required for installing the scum separation tank 2. Furthermore, since the floating matter recovery device 1 is structured to move the suction cup 15 up and down by the air cylinder 19, unlike the case where an electric cylinder is used, there is no need to install a power supply facility or an electric cord near the coolant tank 4. Therefore, even if the coolant 11b is water-soluble, there is no risk of accidents such as short circuits or electric shock. Therefore, the floating matter recovery device 1 can be safely used in the work of recovering scum 11a from the water-soluble coolant 11b.

[0078] Fig. 9(a) is a block diagram showing the configuration of a pneumatic governor (double) (hereinafter referred to as pneumatic circuit 24a) that controls the operation of the air cylinder 19 shown in Fig. 4(a), and Fig. 9(b) is a diagram showing a state in which compressed air is supplied to the pneumatic circuit 24a in Fig. 9(a). Fig. 10(a) is a diagram showing a state in which the first air operated valve 26 in Fig. 9(b) has been switched, and Fig. 10(b) is a diagram showing a state in which the second air operated valve 27 in Fig. 10(a) has been switched. Fig. 11(a) is a diagram showing a state in which the first air operated valve 26 in Fig. 10(b) has been switched, and Fig. 11(b) is a diagram showing a state in which the second air operated valve 27 in Fig. 11(a) has been switched. And Fig. 12 is a flow chart for explaining the operation of the pneumatic circuit 24a. In Figures 9(b) to 11(b), the air tubes through which the compressed air supplied from the air pressure supply source to the air cylinder 19 flows and the air tubes through which the compressed air discharged from the air cylinder 19 flows are shown by thick solid lines and thin solid lines, the air tubes through which the compressed air supplied from the air pressure supply source to the first air chamber 28 and the second air chamber 29 and the first air operated valve 26 and the second air operated valve 27 flows are shown by thick dashed lines, and the air tubes through which the compressed air discharged from the first air chamber 28 and the second air chamber 29 and the first air operated valve 26 and the second air operated valve 27 flows are shown by thin dashed lines.

[0079] As shown in FIG. 9(a), the pneumatic circuit 24a which controls the operation of the air cylinder 19 includes a manual valve 25 to which compressed air is supplied from an air pressure supply source (not shown) via an air tube 33h, a first air operated valve 26 and a second air operated valve 27, a first air chamber 28 and a second air chamber 29, orifices 30a, 30b, a first pressure control valve 31a and a second pressure control valve 31b, a first speed control valve 31c and a second speed control valve 31d, a first rapid exhaust valve 32a and a second rapid exhaust valve 32b, air tubes 33a to 33g, and a first branch tube 34a and a second branch tube 34b.

[0080] The first air operated valve 26 has five ports as well as a first pilot port 26a and a spring 26b. In the initial state shown in Figures 9(a) and 9(b), when compressed air discharged from the air cylinder 19 is supplied to the first pilot port 26a as shown in Figure 9(b), the valve switches to the first state shown in Figures 10(a) and 10(b). Furthermore, when compressed air supplied from the air pressure supply source via the air cylinder 19 acts as a first pilot pressure to the first pilot port 26a as shown in Figure 10(b), the valve switches to the second state shown in Figures 11(a) and 11(b). When the compressed air discharged from the air cylinder 19 is no longer supplied to the first pilot port 26a in the first state, the first air operated valve 26 is switched to the initial state by the biasing force of the spring 26b.

[0081] The second air operated valve 27 has a second pilot port 27a and a third pilot port 27b in addition to the five ports. When a second pilot pressure acts on the second pilot port 27a in the third state shown in Figures 9(a) to 10(a) and 11(b), the valve switches to a fourth state shown in Figures 10(b) and 11(a), and when a third pilot pressure acts on the third pilot port 27b in the fourth state as shown in Figure 11(a), the valve switches to the third state.

[0082] The manual valve 25 and the first air operated valve 26 are connected by an air tube 33a, and the second air operated valve 27 is connected to the end of a first branch tube 34a branched off from the air tube 33a. The first air operated valve 26 and the first air chamber 28 are connected by an air tube 33b, and an orifice 30a and a first rapid exhaust valve 32a are interposed in this air tube 33b, in that order from the side closest to the first air operated valve 26. The first air operated valve 26 and the second air chamber 29 are connected by an air tube 33c, and an orifice 30b and a second rapid exhaust valve 32b are interposed in this air tube 33c, in that order from the side closest to the first air operated valve 26.

[0083] The head side port 19b and the rod side port 19c of the air cylinder 19 are connected to the second air operated valve 27 by air tubes 33d and 33e, respectively. A first speed control valve 31c and a second speed control valve 31d are interposed in the air tubes 33d and 33e for the purpose of adjusting the speed of the compressed air supplied to the head side port 19b and the rod side port 19c of the air cylinder 19. That is, the pneumatic circuit 24a is structured so that the forward and backward speeds of the piston rod 19a can be adjusted individually by operating the first speed control valve 31c and the second speed control valve 31d, respectively.

[0084] The first air chamber 28 and the second air chamber 29 are connected to the second pilot port 27a and the third pilot port 27b of the second air operated valve 27 by air tubes 33f and 33g, respectively, and a first pressure control valve 31a and a second pressure control valve 31b are respectively interposed in the air tubes 33f and 33g. Further, an end of a second branch tube 34b branched off from the air tube 33e is connected to a first pilot port 26a of the first air operated valve 26.

[0085] In FIG. 9(a), when the manual valve 25 is opened to connect the air tube 33h to the air tube 33a, the first branch tube 34a and the air tube 33d are connected in the second air operated valve 27, so that a portion of the compressed air supplied to the air tube 33h from an air pressure supply source (not shown) is supplied to the head side port 19b of the air cylinder 19 through the air tube 33a, the first branch tube 34a, and the air tube 33d, as shown by the thick solid line in FIG. 9(b). As a result, the piston rod 19a of the air cylinder 19 advances (step S1 in FIG. 12). At this time, the compressed air discharged from the rod side port 19c is supplied to the second air operated valve 27 via the air tube 33e as shown by the thin solid line, and then released into the atmosphere.

[0086] In FIG. 9(b), when the first air operated valve 26 is switched from the initial state to the first state shown in FIG. 10(a), the air tubes 33a and 33b are connected in the first air operated valve 26, so that compressed air supplied to the air tube 33h from an air pressure supply source (not shown) passes through the air tubes 33a and 33b as shown by the thick dashed line, has its flow rate controlled by the orifice 30a, and then flows into the inside of the first air chamber 28 through the first rapid exhaust valve 32a.

[0087] When the internal pressure of the first air chamber 28 gradually increases and reaches a value indicating a preset pressure (pilot pressure) for the first pressure control valve 31a, this compressed air flows out of the first air chamber 28 and is supplied to the second pilot port 27a of the second air operated valve 27. Then, this compressed air acts as the second pilot pressure, and the second air operated valve 27 switches from the third state shown in Fig. 10(a) to the fourth state shown in Fig. 10(b) (step S2 in Fig. 12). Furthermore, when compressed air is no longer supplied from the air pressure supply source to air tube 33b via air tubes 33h, 33a, the compressed air inside the first air chamber 28 is instantly released into the atmosphere by the first rapid exhaust valve 32a, causing the inside of the first air chamber 28 to become unpressurized.

[0088] In the pneumatic circuit 24a, when the knob of the first pressure control valve 31a is operated to set the pilot pressure to a high value, the operation of the second air operated valve 27 to switch from the third state to the fourth state is delayed, and the timing at which the piston rod 19a retracts is delayed. Conversely, when the pilot pressure is set to a low value, the operation of the second air operated valve 27 is accelerated, and the timing at which the piston rod 19a retracts is accelerated. That is, in the pneumatic circuit 24a, the timing at which the piston rod 19a retreats can be adjusted by operating the first pressure control valve 31a. The timing of the piston rod 19a can also be adjusted by changing the diameter of the orifice 30a or the volume of the first air chamber 28.

[0089] As shown in FIG. 10(b), when the second air operated valve 27 is in the fourth state, the first branch tube 34a and the air tube 33e are connected in the second air operated valve 27, so that compressed air supplied to the air tube 33h from an air pressure supply source (not shown) is supplied to the rod side port 19c of the air cylinder 19 through the first branch tube 34a and the air tube 33e, as shown by the thick solid line. As a result, the piston rod 19a of the air cylinder 19 retracts (step S3 in FIG. 12). The compressed air discharged from the head side port 19b is supplied to the second air operated valve 27 via the air tube 33d as indicated by the thin solid line, and is then released into the atmosphere. The remainder of the compressed air supplied from the air pressure supply source to the air tube 33e is supplied to the first pilot port 26a of the first air operated valve 26 via the second branch tube 34b as indicated by the thick dashed line.

[0090] In Fig. 10(b), the compressed air supplied to the first pilot port 26a of the first air operated valve 26 acts as a first pilot pressure on the first air operated valve 26. As a result, the first air operated valve 26 switches from the first state shown in Fig. 10(b) to the second state shown in Fig. 11(a) (step S4 in Fig. 12). 11(a), when the first air operated valve 26 is in the second state, the air tube 33a and the air tube 33c are connected in the first air operated valve 26, so that compressed air supplied to the air tube 33h from an air pressure supply source (not shown) passes through the air tubes 33a and 33c as indicated by the thick dashed line, has its flow rate controlled by the orifice 30b, and then passes through the second rapid exhaust valve 32b and flows into the inside of the second air chamber 29. At this time, the compressed air in the air tube 33b is released into the atmosphere via the first air operated valve 26. When the internal pressure of the second air chamber 29 gradually increases and reaches a value indicating a preset pressure (pilot pressure) for the second pressure control valve 31b, compressed air flows out of the second air chamber 29 and is supplied to the third pilot port 27b of the second air operated valve 27. Then, this compressed air acts as the third pilot pressure, and the second air operated valve 27 switches from the fourth state shown in Fig. 11(a) to the third state shown in Fig. 11(b) (step S5 in Fig. 12).

[0091] When compressed air is no longer supplied from the air pressure supply source to the air tube 33c via the air tubes 33h, 33a, the compressed air inside the second air chamber 29 is instantly released into the atmosphere by the second quick exhaust valve 32b, causing the inside of the second air chamber 29 to become unpressurized. In addition, when the pilot pressure is set to a high value by operating the knob of the second pressure control valve 31b, the operation of the second air operated valve 27 to switch from the fourth state to the third state is delayed, and the timing at which the piston rod 19a moves forward is delayed. Conversely, when the pilot pressure is set to a low value, the operation of the second air operated valve 27 is accelerated, and the timing at which the piston rod 19a moves forward is accelerated. That is, in the pneumatic circuit 24a, the timing at which the piston rod 19a advances can be adjusted by operating the second pressure control valve 31b. The timing of the piston rod 19a can also be adjusted by changing the diameter of the orifice 30b or the volume of the second air chamber 29.

[0092] As shown in FIG. 11(b), when the second air operated valve 27 is in the third state, the first branch tube 34a and the air tube 33d are connected in the second air operated valve 27, so that the compressed air supplied to the air tube 33h from an air pressure supply source (not shown) is supplied to the head side port 19b of the air cylinder 19 through the first branch tube 34a and the air tube 33d, as shown by the thick solid line. As a result, the piston rod 19a of the air cylinder 19 moves forward again (step S1 in FIG. 12). At this time, the compressed air discharged from the rod side port 19c is supplied to the second air operated valve 27 via the air tube 33e as shown by the thin solid line, and then released into the atmosphere. The compressed air in the second branch tube 34b is released into the atmosphere via the air tube 33e and the second air operated valve 27. When the second air operated valve 27 is in the third state, the compressed air supplied from the air pressure source to the air tube 33a is no longer supplied to the air tube 33e and the second branch tube 34b, and the first pilot pressure is no longer applied to the first pilot port 26a. As a result, the first air operated valve 26 is switched from the second state to the first state by the biasing force of the spring 26b, and the air pressure circuit 24a returns to the state shown in Fig. 10(a). As a result, the compressed air in the air tube 33c is released into the atmosphere via the first air operated valve 26, and the compressed air in the second air chamber 29 is instantly released into the atmosphere by the second quick exhaust valve 32b, so that the inside of the second air chamber 29 becomes unpressurized.

[0093] In this manner, when compressed air is supplied to the pneumatic circuit 24a, it acts on the air cylinder 19 to repeatedly move the piston rod 19a forward and backward at a predetermined cycle. As already explained with reference to Figures 4 to 6, the suction cup 15 is connected to the tip of the piston rod 19a via the suspension rod 20. Therefore, after adjusting the stroke of the piston rod 19a in advance so that the piston rod 19a is in the state shown in Figures 8(a) and 8(b) when it is in the most advanced position and the most retracted position, respectively, the float suction 5 is floated on the liquid surface 11c of the coolant 11b stored in the coolant tank 4, and the air cylinder 19 is operated in this state, the suction cup 15 moves up and down with the advancement and retraction of the piston rod 19a, and a certain amount of scum 11a floating on the liquid surface 11c of the coolant 11b flows into the inside of the suction cup 15. This phenomenon is repeated at a certain period. In this way, in the floating matter recovery device 1 equipped with the air pressure circuit 24a, simply by supplying compressed air to the air pressure circuit 24a, a certain amount of scum 11a recovered from the coolant tank 4 is repeatedly supplied to the scum separation tank 2 at a predetermined cycle, thereby reliably achieving the effect of efficiently recovering the scum 11a from the coolant 11b.

[0094] In the above description of the pneumatic circuit 24a, the air tubes 33d, 33e are connected to the head side port 19b and the rod side port 19c of the air cylinder 19, respectively, but the air tubes 33e, 33d may be connected to the head side port 19b and the rod side port 19c of the air cylinder 19, respectively. In this case, the order of the advancement and retraction of the piston rod 19a of the air cylinder 19 is reversed from that described above, but the action of the piston rod 19a of the air cylinder 19 repeating advancement and retraction at a predetermined cycle and the action of individually changing the retraction timing and advancement timing of the piston rod 19a by changing the set values ​​of the pilot pressures in the first pressure control valve 31a and the second pressure control valve 31b are similarly exerted. EXAMPLES

[0095] The floating object recovery device 1 described below is characterized in that it includes an air pressure circuit 24b, which will be described with reference to Figs. 13 to 15, instead of the air pressure circuit 24a in the first embodiment. Fig. 13(a) is a block diagram showing the configuration of a pneumatic governor (single) (hereinafter referred to as pneumatic circuit 24b), and Fig. 13(b) is a diagram showing a state in which compressed air is supplied to pneumatic circuit 24b in Fig. 13(a). Fig. 14(a) is a diagram showing how pilot pressure acts on pilot port 35a of air operated valve 35 in Fig. 13(b), and Fig. 14(b) is a diagram showing a state in which air operated valve 35 has been switched in Fig. 14(a). Furthermore, Fig. 15 is a flow chart for explaining the operation of pneumatic circuit 24b. In Figures 13 and 14, the air tube through which the compressed air supplied from the air pressure supply source to the air cylinder 19 flows and the air tube through which the compressed air discharged from the air cylinder 19 flows are shown by thick solid lines and thin solid lines, the air tube through which the compressed air supplied from the air pressure supply source to the air chamber 40 and the air operated valve 35 flows are shown by thick dashed lines, and the air tube through which the compressed air discharged from the air chamber 40 and the air operated valve 35 flows are shown by thin dashed lines.

[0096] As shown in FIG. 13(a), the pneumatic circuit 24b which controls the operation of the air cylinder 19 includes a manual valve 25 to which compressed air is supplied from an air pressure supply source (not shown) via an air tube 36e, an air operated valve 35, an air chamber 40, orifices 30a, 30c, a pressure control valve 38, a first speed control valve 31c and a second speed control valve 31d, a quick exhaust valve 39, air tubes 36a to 36d, and a branch tube 37.

[0097] In addition to the five ports, the air operated valve 35 has a pilot port 35a and a spring 35b. In the first state shown in Figures 13(a), 13(b), and 14(a), when pilot pressure acts on pilot port 35a as shown in Figure 14(a), the state switches to the second state shown in Figure 14(b). In addition, when pilot pressure no longer acts on pilot port 35a in the second state, the state switches from the second state to the first state by the biasing force of spring 35b.

[0098] The manual valve 25 and the air operated valve 35 are connected via an air tube 36a, and an air chamber 40 is connected to a branch tube 37 branching off from the air tube 36b. An orifice 30a and a quick exhaust valve 39 are disposed in the branch tube 37, in that order from the side closest to the air operated valve 35, and an orifice 30c is provided at the exhaust port of the quick exhaust valve 39. The head side port 19b and the rod side port 19c of the air cylinder 19 are connected to an air operated valve 35 by air tubes 36b and 36c, respectively. A first speed control valve 31c and a second speed control valve 31d are respectively provided in the air tubes 36b and 36c for the purpose of adjusting the speed of the compressed air supplied to the head side port 19b and the rod side port 19c of the air cylinder 19. That is, the pneumatic circuit 24b is structured so that the forward speed and the backward speed of the piston rod 19a can be adjusted individually by operating the first speed control valve 31c and the second speed control valve 31d, respectively. The air chamber 40 is connected to the pilot port 35a of the air operated valve 35 by an air tube 36d, and a pressure control valve 38 is provided in the air tube 36d.

[0099] In FIG. 13(a), when the manual valve 25 is opened to connect the air tube 36e to the air tube 36a, the air tube 36a and the air tube 36b are connected in the air operated valve 35, so that a portion of the compressed air supplied to the air tube 36e from an air pressure supply source (not shown) is supplied to the head side port 19b of the air cylinder 19 through the air tubes 36a and 36b, as shown by the thick solid line in FIG. 13(b). As a result, the piston rod 19a of the air cylinder 19 advances (step S1 in FIG. 15). At this time, the compressed air discharged from the rod side port 19c is supplied to the air operated valve 35 via the air tube 36c, and then released into the atmosphere. On the other hand, the remainder of the compressed air supplied from air tube 36a to air tube 36b passes through branch tube 37, as indicated by the thick dashed line, has its flow rate controlled by orifice 30a, and then flows into the inside of air chamber 40 through quick exhaust valve 39.

[0100] When the internal pressure of the air chamber 40 gradually increases and reaches a value indicating a preset pressure (pilot pressure) for the pressure control valve 38, compressed air flows out of the air chamber 40 and is supplied to the pilot port 35a of the air operated valve 35 through the air tube 36d as shown by the thick dashed line in Fig. 14(a). Then, this compressed air acts as the pilot pressure, and the air operated valve 35 switches from the first state shown in Fig. 14(a) to the second state shown in Fig. 14(b) (step S2 in Fig. 15). When compressed air is no longer supplied from the air pressure supply source to the air tube 36b via the air tube 36e and the air tube 36a, the compressed air inside the air chamber 40 is instantly released into the atmosphere by the quick exhaust valve 39, so that the inside of the air chamber 40 becomes unpressurized. When the air operated valve 35 enters the second state, the compressed air inside the air tube 36b and the branch tube 37 is released into the atmosphere via the air operated valve 35.

[0101] When the pilot pressure is set to a high value by operating the knob of the pressure control valve 38, the operation of the air operated valve 35 to switch from the first state to the second state is slowed down, and the timing at which the piston rod 19a retracts is delayed. Conversely, when the pilot pressure is set to a low value, the operation of the air operated valve 35 is accelerated, and the timing at which the piston rod 19a retracts is accelerated. That is, in the pneumatic circuit 24b, the timing at which the piston rod 19a retreats can be adjusted by operating the pressure control valve 38. The timing of the piston rod 19a can also be adjusted by changing the diameters of the orifices 30a and 30c and the volume of the air chamber 40.

[0102] When the air operated valve 35 is in the second state, the air tubes 36a and 36c are connected in the air operated valve 35, so that compressed air supplied from an air pressure supply source (not shown) via the air tube 36e to the air tube 36a is supplied to the rod side port 19c of the air cylinder 19 through the air tube 36c as shown in FIG. 14(b). As a result, the piston rod 19a of the air cylinder 19 retracts (step S3 in FIG. 15). The compressed air discharged from the head side port 19b is supplied to the air operated valve 35 via the air tube 36b, and then released into the atmosphere. Furthermore, when the air operated valve 35 is in the second state, compressed air is no longer supplied from the air pressure supply source to the second air tube 36b via the air tube 36e and the air tube 36a. As a result, as already described, the compressed air remaining inside the air chamber 40 is instantly released into the atmosphere by the quick exhaust valve 39, and the inside of the air chamber 40 becomes pressureless, so that pilot pressure no longer acts on the pilot port 35a. As a result, the air operated valve 35 is switched from the second state to the first state by the biasing force of the spring 35b (step S4 in FIG. 15), and the air pressure circuit 24b returns to the state shown in FIG. 13(b).

[0103] The pneumatic circuit 24b having the air operated valve 35 and the air chamber 40 has a simpler structure than the pneumatic circuit 24a having the first air operated valve 26, the second air operated valve 27, the first air chamber 28, and the second air chamber 29, but has the same function of repeatedly moving the piston rod 19a forward and backward with respect to the air cylinder 19 at a predetermined cycle by supplying compressed air. Therefore, in the floating matter recovery device 1 having the pneumatic circuit 24b, a certain amount of scum 11a recovered from the coolant tank 4 is repeatedly supplied to the scum separating tank 2 at a predetermined cycle, so that the effect of efficiently recovering the scum 11a from the coolant 11b is also achieved. Therefore, by using the pneumatic circuit 24b instead of the pneumatic circuit 24a, the manufacturing cost of the floating matter recovery device 1 can be reduced.

[0104] In the above description of the pneumatic circuit 24b, the air tubes 36b, 36c are connected to the head side port 19b and the rod side port 19c of the air cylinder 19, respectively, but the air tubes 36c, 36b may be connected to the head side port 19b and the rod side port 19c of the air cylinder 19, respectively. In this case, the order of the advancement and retraction of the piston rod 19a of the air cylinder 19 is reversed from that described above, but the action of the piston rod 19a of the air cylinder 19 repeating advancement and retraction at a predetermined cycle is similarly exerted. However, when the set value of the pilot pressure in the pressure control valve 38 is changed, the timing of the advancement of the piston rod 19a changes, not the timing of the retraction. [Industrial Applicability]

[0105] The floating matter recovery device of the present invention can be used to recover floating matter such as scum and oil that rises to the surface of coolant used for lubrication and cooling in primary processing (forging, molding using a heading machine, etc.) and secondary processing (grinding finishing) in machine tools. [Explanation of symbols]

[0106] 1...Floating matter recovery device 2...Scum separation tank 2a...Scum discharge port 2b...Scum supply port 2c...Coolant discharge port 2d...Side plate 2e...Separation chamber 2f...Clear liquid storage chamber 2g...Bottom plate 2h...Level 2i...Opening 2j...Scum discharge chute 2k...Lower edge 3...Coolant discharge pipe 3a, 3b...L-shaped pipe 3c...Liquid level adjustment socket 3d...Lower end 3e...Upper end 3f...Straight pipe 4...Coolant tank 5...Float suction 5a...Suction port 6...Scum suction pipe 7...Filter 8...Air-driven diaphragm pump 9...Scum tank 10...Mounting plate 11a...Scum 11b...Coolant 11c...Liquid level 12...Partition plate 12a...Liquid passage port 12b...Screw insertion hole 13...Scum supply pipe 13a...connecting pipe 13b...straight pipe 13c...L-shaped pipe 13d...T-shaped pipe 14a, 14b...flat plate portion 14c...connecting portion 15...suction cup 15a...bottom surface 15b...side surface 15c...through hole 15d...guide hole 15e...upper end surface 16...connecting plate 16a...arm portion 16b...lower surface 16c...upper surface 17a, 17b...bolt 18...float 19...air cylinder 19a...piston rod 19b...head side port 19c...rod side port 20...suspended rod 20a...upper end 20b...lower end 21...anti-rotation nut 22a...collar 22b...washer 22c...floating joint 23...guide pin 23a...upper end 23b...lower end 24a, 24b...pneumatic circuit Reference Signs List 25...Manual valve 26...First air operated valve 26a...First pilot port 26b...Spring 27...Second air operated valve 27a...Second pilot port 27b...Third pilot port 28...First air chamber 29...Second air chamber 30a-30c...Orifice 31a...First pressure control valve 31b...Second pressure control valve 31c...First speed control valve 31d...Second speed control valve 32a...First quick exhaust valve 32b...Second quick exhaust valve 33a-33h...Air tube 34a...First branch tube 34b...Second branch tube 35...Air operated valve 35a...Pilot port 35b...Spring 36a-36e...Air tube 37...Branch tube 38...Pressure control valve 39: quick exhaust valve 40: air chamber 41: suction cup 41a: slit 41b: lowest part

Claims

1. A floating matter recovery device that recovers floating matter such as scum and oil that floats on the liquid surface of a coolant used for lubricating and cooling a machining part in a machine tool, a coolant tank in which the coolant is stored together with the floating matter; a float suction device having a float made of a material having a smaller specific gravity than the coolant, the float suction device being installed in the coolant tank so as to float on the surface of the coolant so that the floating matter floating on the surface of the coolant flows into the inside of the float suction device; a floating matter separating tank having a floating matter discharge port, a floating matter supply port, and a coolant discharge port; a floated matter suction pipe having one end connected to the floated matter supply port of the floated matter separation tank and the other end connected to the suction port of the float suction; a pump that sends the floating matter from the float suction to the floating matter separation tank through the floating matter suction pipe, The float suction is A connecting plate to which the float is connected; an air cylinder installed on the connecting plate with a tip of a piston rod facing downward; A floating object recovery device characterized in that the suction port is provided at a lower portion and a suction cup is connected to the tip of the piston rod in an upwardly opening position.

2. 2. The floating object recovery device according to claim 1, further comprising a pneumatic circuit for controlling the operation of the air cylinder so that the piston rod repeatedly moves forward and backward cyclically.

3. a first air operated valve having a first pilot port and a spring and supplied with compressed air via a first flow path; a second air operated valve having a second pilot port and a third pilot port and connected to a first branch passage branching from the first passage; a second flow passage and a third flow passage connecting the second air operated valve to a first cylinder port and a second cylinder port of the air cylinder, respectively; a second branch passage connecting the third passage and the first pilot port; a first air chamber and a second air chamber connected to the first air operated valve via a fourth flow passage and a fifth flow passage, respectively; a sixth flow passage connecting the second pilot port and the first air chamber and a seventh flow passage connecting the third pilot port and the second air chamber; a first pressure control valve and a second pressure control valve respectively disposed in the sixth flow path and the seventh flow path, When a first pilot pressure is applied to the first pilot port, the first air operated valve switches from a first state in which the first flow path and the fourth flow path communicate with each other and the compressed air in the fifth flow path is discharged into the atmosphere to a second state in which the first flow path and the fifth flow path communicate with each other and the compressed air in the fourth flow path is discharged into the atmosphere, whereas when the first pilot pressure is no longer applied to the first pilot port, the first air operated valve switches from the second state to the first state by the biasing force of the spring, The floating object recovery device described in claim 2, characterized in that when a second pilot pressure acts on the second pilot port, the second air operated valve switches from a third state in which the first branch flow path and the second flow path are connected and the compressed air in the third flow path and the second branch flow path is released into the atmosphere to a fourth state in which the first branch flow path and the third flow path are connected and the compressed air in the second flow path is released into the atmosphere, whereas when a third pilot pressure acts on the third pilot port, the second air operated valve switches from the fourth state to the third state.

4. an air operated valve having a pilot port and a spring and supplied with compressed air via a first flow path; a second flow passage and a third flow passage connecting the air operated valve to a first cylinder port and a second cylinder port of the air cylinder, respectively; an air chamber connected to a branch flow path branched from the second flow path; a fourth flow passage connecting the air chamber and the pilot port; a pressure control valve disposed in the fourth flow path, The floating object recovery device described in claim 2, characterized in that when a pilot pressure is applied to the pilot port, the air operated valve switches from a first state in which the first flow path and the second flow path are connected and the compressed air in the third flow path is released into the atmosphere to a second state in which the first flow path and the third flow path are connected and the compressed air in the second flow path and the branch flow path is released into the atmosphere, whereas when the pilot pressure is no longer applied to the pilot port, the air operated valve switches from the second state to the first state due to the biasing force of the spring.

5. a guide pin arranged parallel to the moving direction of the piston rod and having an upper end fixed to the connecting plate; 3. The floating object recovery device according to claim 1, wherein the suction cup is provided with a guide portion that guides the guide pin in a direction parallel to the moving direction of the piston rod.

6. 3. The floating object recovery device according to claim 1, further comprising a rod-shaped body, the tip of the piston rod being connected to an upper end and the lower end being connected to the suction cup.

7. a locking nut having an internal thread on its inner circumferential surface that screws into a male thread on an outer circumferential surface of the tip of the piston rod; the rod-shaped body is a cylindrical suspension rod having an internal thread on an inner circumferential surface thereof, the internal thread being adapted to be screwed into the external thread of the piston rod; A floating object recovery device as described in claim 6, characterized in that the tip of the piston rod is screwed into the upper end of the suspension rod, and the anti-rotation nut is installed at the upper end of the suspension rod with the tip of the piston rod screwed in.

8. A cylindrical body loosely inserted into a through hole provided on a bottom surface of the suction cup; A bolt is inserted into the cylindrical body from below the suction cup; a washer disposed between the cylindrical body and the suspension rod with the bolt inserted therein; 8. The floating object recovery device according to claim 7, wherein the lower end of the suspension rod is fixed to the suction cup by the bolt.

9. 8. The floating object recovery device according to claim 7, wherein the piston rod and the suspension rod are connected via a floating joint.

10. The floatation separation tank comprises: a separation chamber provided with the floated matter supply port and the floated matter discharge port; a clear liquid storage chamber provided with the coolant discharge port, 2. The floating matter recovery device according to claim 1, wherein the separation chamber and the clear liquid storage chamber are connected at a lower part of the floating matter separation tank.

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