filtration device

Abstract

This filtration system improves work efficiency by collecting the foam from the dirty liquid that overflows from the filtration tank, thereby reducing the need for floor cleaning and other related tasks. [Solution] The filtration device (1) comprises a filtration tank (11), a strip-shaped filter cloth (15), a pair of side wall covers (41A, 41B), and a drain pan (51). The filtration tank (11) has a foam outlet (11H) formed above the normal liquid level of the dirty liquid (DF) on at least one of the pair of opposing side walls (11E, 11F). The upper edges of the pair of side wall covers (41A, 41B) are located above the foam outlet (11H).

Description

Technical Field

[0001] This disclosure relates to a filtering device.

Background Art

[0002] Various filtering devices for filtering grinding fluid and cutting fluid of a working device have been proposed. In the filtering device described in Patent Document 1, the cutting and grinding fluid (coolant) discharged from a machine tool is supplied to a reservoir portion of a filtering belt. When the liquid level in the reservoir portion rises, the filtering belt moves, and the filtering belt from which sludge has been removed is moved to the reservoir portion to lower the liquid level. Then, the clean filtered liquid that has passed through the filtering belt and from which sludge has been removed flows from a receiving tank into a filtering tank and is configured to be circulated to the machine tool via a circulation pump and used.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the conventional configuration, when a water-soluble coolant discharged from a machine tool is supplied to the reservoir portion, more bubbles are generated compared to an oil-based coolant and overflow from the filtering device, which may stain the floor surface where the filtering device is installed with the coolant.

[0005] One aspect of this disclosure aims to provide a filtering device that can improve work efficiency by collecting bubbles of dirty liquid overflowing from a filtering tank and reducing opportunities for floor cleaning and the like.

Means for Solving the Problems

[0006] To solve the above problems, a filtration apparatus according to one aspect of the present disclosure comprises a filtration tank to which dirty liquid is supplied; an endless annular strip of filter cloth that is conveyed by a drive roller and a driven roller to filter the dirty liquid supplied to the filtration tank; a pair of side wall covers that are arranged opposite to each other at a predetermined distance apart on the outside of each of a pair of opposing side walls of the filtration tank arranged along the conveying direction of the strip of filter cloth; and a drain pan sandwiched between the pair of side wall covers and positioned below the filtration tank, wherein the filtration tank has a foam outlet formed above the normal liquid level of the dirty liquid in the filtration tank on at least one of the pair of side walls, and the upper edges of the pair of side wall covers are located above the foam outlet. [Effects of the Invention]

[0007] According to one aspect of this disclosure, by recovering the foam from the dirty liquid overflowing from the filtration tank, the need for floor cleaning and other tasks can be reduced, thereby improving work efficiency. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic front view illustrating the filtration apparatus according to this embodiment. [Figure 2] This is a schematic side view taken along arrow II in Figure 1. [Figure 3] This is an enlarged view of section III in Figure 2. [Modes for carrying out the invention]

[0009] Hereinafter, one embodiment of the present disclosure will be described in detail with reference to Figures 1 to 3. For the sake of clarity in the following description, the up-down direction, left-right direction, and front-back direction will be defined as indicated by the arrows in each figure. The left-right direction and the front-back direction may also be referred to as the "horizontal direction." Furthermore, the direction from the inside to the outside of the filtration device 1 will be defined as the "outward direction," and the direction from the outside to the inside of the filtration device 1 will be defined as the "inward direction."

[0010] (System configuration of the filtration device) The schematic system configuration of the filtration device 1 according to this embodiment will be described with reference to Figure 1. Figure 1 is a schematic front view illustrating the filtration device 1 according to this embodiment. As shown in Figure 1, clean liquid CF is sent from the clean tank 6 to the processing device 2 by the discharge pump 7, and dirty liquid DF, which is grinding fluid or cutting fluid, is supplied from the processing device 2 to the filtration tank 11 of the filtration device 1 at the dirty liquid supply port 28 of the filtration device 1. The processing device 2 is, for example, a grinding machine for polishing metal or a cutting machine for cutting metal. The dirty liquid DF contains sludge generated by processing, abrasive particles from grinding wheels, etc.

[0011] Furthermore, when the operator switches the vacuum switch 5 from off to on, the purified coolant, i.e., clean liquid CF, from the filtration box 31 into which the purified coolant from the filtration device 1 flows is sent to the clean tank 6 by the suction pump 3. The suction pump 3 creates negative pressure inside the filtration box 31, thereby forcibly sucking and filtering the dirty liquid DF in the filtration tank 11 through the strip-shaped filter cloth 15 (see Figure 2). This ensures efficient filtration. The filtered clean liquid CF is sent through the piping 33 to the clean liquid outlet 29 and then to the suction pump 3, and finally stored in the clean tank 6.

[0012] (Outline configuration of the filtration system) Next, the schematic configuration of the filtration device 1 will be described based on Figures 1 and 2. Figure 2 is a schematic side view taken in the direction of arrow II in Figure 1. As shown in Figures 1 and 2, the filtration device 1 consists of a filtration tank 11, a pair of side wall covers 41A and 41B arranged on the outside of the filtration tank 11 along the conveying direction of the strip-shaped filter cloth 15 in the filtration tank 11, and a drain pan 51 arranged on the lower side of the filtration tank 11.

[0013] Furthermore, the filtration device 1 includes a front cover 61 that covers the diagonally upper front side of the filtration tank 11 and a rear cover 62 that covers the diagonally upper rear side. The front cover 61 and the rear cover 62 are configured to be rotatable in the vertical direction. The filtration device 1 has a double-tank structure or a leak-proof cover structure, and the filtration tank 11 (inner tank) is covered by a pair of side wall covers 41A and 41B (part of the outer tank), the front cover 61, the rear cover 62, and the drain pan 51.

[0014] (Outline configuration of the filtration tank) Next, the general configuration of the filtration tank 11 will be described based on Figures 1 and 2. As shown in Figures 1 and 2, the filtration tank 11 consists of a front wall 11A, a rear wall 11B, a bottom wall 11C that protrudes downward in a roughly L-shaped cross-section, a pair of side walls 11E and 11F, and an upper wall 11D. These walls form a space in which dirty liquid DF can be stored.

[0015] As shown in Figures 1 and 2, a dirty liquid supply port 28 is provided on one side wall 11E to supply dirty liquid DF into the filtration tank 11. Piping from the processing device 2 is connected to the dirty liquid supply port 28, and dirty liquid DF containing sludge is supplied to it.

[0016] As shown in Figures 1 and 2, one side wall 11E is provided with a roughly elongated rectangular foam outlet 11H near the dirty liquid supply port 28, positioned slightly above the normal liquid level of the dirty liquid DF to discharge foam. The normal liquid level of the dirty liquid DF is, for example, located on a plane passing through the center of the dirty liquid supply port 28. If the dirty liquid DF is a water-soluble coolant, it is prone to foaming, and a large amount of foam may be generated above the liquid surface. The foam outlet 11H is an opening (window) for intentionally releasing such foam to the outside of the filtration tank 11 (but inside the side wall cover 41A).

[0017] Furthermore, the other side wall 11F is provided with a roughly horizontally elongated rectangular foam outlet 11H at a position opposite to the foam outlet 11H of the side wall 11E. Note that the foam outlet 11H may be provided on only one of the side walls 11E and 11F.

[0018] As shown in FIGS. 1 and 2, a liquid level sensor 14 for measuring the level of the dirty liquid DF in the filtration tank 11 is provided on the upper wall 11D. The liquid level sensor 14 monitors the liquid level in the filtration tank 11 and is used, for example, to issue an alarm when the liquid level rises abnormally or to control the conveyance of the belt filter cloth 15.

[0019] As shown in FIG. 2, an endless annular belt filter cloth 15 is conveyed into the filtration tank 11 from a filter cloth inlet 13 provided on the front wall 11A by a tension roller 16, respective pressing rollers 17, a driving roller 18, respective guide rollers 19A and 19B, and respective driven rollers 21A and 21B. The belt filter cloth 15 that has entered the filtration tank 11 is guided by the respective pressing rollers 17, conveyed along the bottom wall 11C having a substantially L-shaped cross section, exits the filtration tank 11 from a filter cloth outlet 24 provided on the rear wall 11B, and is circulated and conveyed by the driving roller 18.

[0020] The belt filter cloth 15 sent out by the driving roller 18 is guided again to the tension roller 16 by the respective guide rollers 19A and 19B and the respective driven rollers 21A and 21B. The tension roller 16 applies a predetermined tension by pulling the belt filter cloth 15 upward by a coil spring or the like (not shown). Further, the driving roller 18 is driven by a first motor 18A to convey the belt filter cloth 15.

[0021] As shown in FIG. 2, in the vicinity of the lower end of the rear wall of the bottom wall 11C having a substantially L-shaped cross section, a suction hole 11G having a substantially horizontally long rectangular shape in plan view for sucking the dirty liquid DF through the belt filter cloth 15 is provided over substantially the entire width in a direction orthogonal to the conveyance direction of the belt filter cloth 15. The suction hole 11G is a main region where the filtration process is performed.

[0022] As shown in FIG. 2, a plurality (for example, eight) of cylindrical driven rollers 12 are rotatably arranged in the suction hole 11G of the bottom wall 11C so as to be orthogonal to the conveyance direction of the belt filter cloth 15, preventing the belt filter cloth 15 from being sucked into the suction hole 11G. Thereby, the belt filter cloth 15 is conveyed smoothly. <00

[0023] As shown in Figures 1 and 2, a filter box 31 with a roughly triangular cross-section is attached to the suction port 11G from the rear, ensuring a liquid-tight seal over approximately the entire width in a direction perpendicular to the conveying direction of the strip-shaped filter cloth 15. The filter box 31 is also called a vacuum box, and its interior is kept under negative pressure by the suction of the suction pump 3. One end of a pipe 33, which discharges the clean liquid CF purified by passing through the strip-shaped filter cloth 15 to the outside, is connected to the rear end of the filter box 31. The other end of the pipe 33 is connected to a clean liquid outlet 29 provided in the side wall cover 41A.

[0024] As shown in Figure 2, a dewatering roller 22 is provided that is pressed against the drive roller 18 and rotates in accordance with the drive roller 18 to dewater the strip-shaped filter cloth 15. The dewatering roller 22 pressurizes the strip-shaped filter cloth 15 discharged from the filtration tank 11 by sandwiching it with the drive roller 18 using a biasing member such as a spring, and squeezes out the water contained in the strip-shaped filter cloth 15. The clean liquid CF dewatered by the dewatering roller 22 flows back into the filtration tank 11 or the drain pan 51 described later. Here, the foam outlet 11H is located above the normal liquid level of the dirty liquid DF in the filtration tank 11 and below the lower end of the dewatering roller 22.

[0025] As shown in Figure 2, the sludge adhering to the outer surface of the dewatered strip-shaped filter cloth 15 is separated by a rotating brush 23 positioned opposite the guide roller 19A. The rotating brush 23 is driven by a second motor 23A and rotates in the opposite direction to the direction of travel of the strip-shaped filter cloth 15 to efficiently scrape off the sludge. The separated sludge is then guided by a sludge guide plate 27 into a sludge container 25.

[0026] (Outline configuration of the side wall cover) Next, the general configuration of the side wall covers 41A and 41B will be explained based on Figures 1 and 2. As shown in Figures 1 and 2, the roughly rectangular side wall covers 41A and 41B are positioned opposite each other, separated by a predetermined distance (for example, 10 mm to 20 mm) from the side walls 11E and 11F of the filtration tank 11. This gap serves as a flow path for the foam of the dirty liquid DF overflowing from the foam outlet 11H and the defoamed dirty liquid to flow down.

[0027] Furthermore, each side wall cover 41A and 41B is formed to be a predetermined height higher than the upper end of the filtration tank 11 and a predetermined height lower than the bottom surface of the filtration tank 11 and the filtration box 31. In addition, each side wall cover 41A and 41B is formed to protrude outward in the front-rear direction from the filtration tank 11 and completely cover the outside of the filtration tank 11 in the left-right direction. Note that the upper edges of each side wall cover 41A and 41B should be higher than the foam outlet 11H. This prevents foam from the dirty liquid DF discharged from the foam outlet 11H from overflowing the side wall covers 41A and 41B and scattering to the outside.

[0028] (Outline configuration of the drain pan) Next, the general configuration of the drain pan 51 will be explained based on Figures 1 to 3. Figure 3 is an enlarged view of part III in Figure 2. As shown in Figures 1 and 2, the drain pan 51, which is roughly rectangular in plan view, is positioned below the filtration tank 11, the filtration box 31, and each driven roller 21A, 21B. The drain pan 51 is fixed by bolts or the like, sandwiched between each side wall cover 41A, 41B, at a position slightly above the lower end of each side wall cover 41A, 41B. The left and right side walls of the drain pan 51 are also fixed to each side wall cover 41A, 41B in a liquid-tight manner. The drain pan 51, together with the side wall covers 41A, 41B, also serves as an outer case that covers the outside of the filtration tank 11.

[0029] As shown in Figures 1 and 2, the drain pan 51, which is roughly rectangular in plan view, protrudes outward by a predetermined distance (for example, 10 mm to 20 mm) from the left and right side walls 11E and 11F of the filtration tank 11. The front edge of the drain pan 51 reaches near the front edges of each side wall cover 41A and 41B, and the rear edge is located slightly behind the rear end of the filtration tank 11. As a result, the drain pan 51 can receive the foam of the dirty liquid DF that overflows from the foam outlet 11H of the filtration tank 11, as well as the defoamed dirty liquid DF.

[0030] As shown in Figures 1 to 3, the drain pan 51, which is roughly rectangular in plan view, is formed in a shallow, roughly box-like shape with an opening at the top. The drain pan 51 also has a water collection section 51A at its front end, which is slightly deeper than the rear end and extends across its entire width in the left-right direction, so that the dirty liquid DF that flows into the drain pan 51 collects and accumulates in the water collection section 51A. A liquid level sensor 52 is also positioned in the water collection section 51A as a water level gauge to measure the water level of the dirty liquid DF accumulated in the water collection section 51A.

[0031] Furthermore, a recovery pump 53 is located in the water collection section 51A to send the dirty liquid DF accumulated in the water collection section 51A to the filtration tank 11 for recovery in the filtration tank 11. The liquid level sensor 52 and the recovery pump 53 are electrically connected to a drive circuit (not shown). The drive circuit (not shown) is configured to measure the water level of the dirty liquid DF accumulated in the water collection section 51A using the liquid level sensor 52, and when the water level exceeds a predetermined level, to drive the recovery pump 53 to return the dirty liquid DF accumulated in the water collection section 51A to the filtration tank 11.

[0032] Furthermore, the drain pan 51 is liquid-tightly attached to each side wall cover 41A, 41B with its bottom surface inclined so that it gradually slopes downward from the rear edge towards the water collection section 51A across its entire width in the left-right direction. The bottom surface of the water collection section 51A may also be inclined so that it gradually slopes downward towards the position where the recovery pump 53 is located.

[0033] As shown in Figures 1 to 3, the foam of the dirty liquid DF that is generated and accumulated in the filtration tank 11 flows out through a pair of foam outlets 11H provided on each side wall 11E and 11F between the side walls 11E and 11F of the filtration tank 11 and the side wall covers 41A and 41B. Subsequently, the foam of the dirty liquid DF that has flowed out from each foam outlet 11H is defoamed and flows downward along each side wall 11E and 11F and each side wall cover 41A and 41B into the drain pan 51. The foam that overflows from the foam outlets 11H is defoamed as it flows down along the side walls 11E and 11F and the side wall covers 41A and 41B, and as it remains on the drain pan 51, returning to a liquid dirty liquid DF. The dirty liquid DF that has flowed into the drain pan 51 accumulates in the water collection section 51A, and when it reaches a predetermined water level, it is returned to the filtration tank 11 by the recovery pump 53.

[0034] (Effects and Benefits) As described in detail above, the filtration device 1 according to this embodiment provides the following effects.

[0035] (1) According to the above configuration, the foam of the dirty liquid DF generated in the filtration tank 11 overflows from the foam outlet 11H formed on the side walls 11E and 11F of the filtration tank 11 between the side wall covers 41A and 41B. The foam of the dirty liquid DF overflowing from the foam outlet 11H flows down along the side walls 11E and 11F of the filtration tank 11 and the side wall covers 41A and 41B, and flows into the drain pan 51 sandwiched between the side wall covers 41A and 41B. As a result, the foam of the dirty liquid DF overflowing from the foam outlet 11H of the filtration tank 11 is collected by the drain pan 51, reducing the need for floor cleaning and thus improving work efficiency.

[0036] (2) With the above configuration, the dirty liquid DF collected in the drain pan 51 can be returned to the filtration tank 11 by the recovery pump 53, and the dirty liquid DF that overflows from the foam outlet 11H of the filtration tank 11 can be reused.

[0037] (3) With the above configuration, the foam outlet 11H is located above the normal liquid level of the dirty liquid DF in the filtration tank 11 and below the lower end of the dewatering roller 22, so that foam from the dirty liquid DF on the dewatering roller 22 side can be effectively prevented.

[0038] (4) With the above configuration, since the foam outlet 11H is formed on both of the pair of side walls 11E and 11F of the filtration tank 11, the foam of the dirty liquid DF can be discharged more efficiently and collected in the drain pan 51.

[0039] <Summary> This disclosure includes at least the following aspects:

[0040] (Composition 1) The filtration apparatus according to this disclosure comprises a filtration tank to which dirty liquid is supplied; an endless annular strip of filter cloth that is conveyed by a drive roller and a driven roller to filter the dirty liquid supplied to the filtration tank; a pair of side wall covers that are positioned opposite to each other at a predetermined distance apart on the outside of a pair of opposing side walls of the filtration tank arranged along the conveying direction of the strip of filter cloth; and a drain pan sandwiched between the pair of side wall covers and positioned below the filtration tank, wherein the filtration tank has a foam outlet formed above the normal liquid level of the dirty liquid in the filtration tank on at least one of the pair of side walls, and the upper edges of the pair of side wall covers are located above the foam outlet.

[0041] (Configuration 2) Furthermore, in configuration 1 of the filtration device according to this disclosure, the drain pan may have a water collection section of a predetermined depth where the recovered dirty liquid is collected, and a recovery pump that returns the dirty liquid from the water collection section to the filtration tank.

[0042] (Composition 3) Furthermore, the filtration apparatus according to this disclosure may also be configured such that, in configuration 1 or 2, it is pressed against the drive roller and rotates in accordance with the drive roller to dewater the strip-shaped filter cloth, and the foam discharge port is located above the normal liquid level of the dirty liquid in the filtration tank and below the lower end of the dewatering roller.

[0043] (Composition 4) Furthermore, the filtration device according to this disclosure may be configured such that, in any one of the configurations 1 to 3, the foam outlet is formed on both of the pair of side walls.

[0044] [Additional Notes] This disclosure is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of this disclosure. [Explanation of Symbols]

[0045] 1 Filtration device 11 Filtration tank 11E, 11F side wall 11H Foam outlet 15. Strip-shaped filter cloth 18 drive rollers 21A, 21B Driven rollers 22 Dehydrating roller 41A Side wall cover 41B Side wall cover 51 Drain pan 51A Water collection section 53 Recovery pump CF Cleaning Solution DF Dirty Liquid

Claims

1. A filtration tank into which the dirty liquid is supplied, An endless annular strip of filter cloth is conveyed by a driven roller and a driven roller to filter the dirty liquid supplied to the filtration tank, A pair of side wall covers are arranged opposite to each other at a predetermined distance apart on the outside of each of the pair of opposing side walls of the filtration tank, which are arranged along the transport direction of the strip-shaped filter cloth, A drain pan is sandwiched between the pair of side wall covers and positioned below the filter tank, Equipped with, The filtration tank has a foam outlet formed above the normal liquid level of the dirty liquid in the filtration tank on at least one of the pair of side walls. The upper edges of the pair of side wall covers are located above the foam discharge port. A filtration device characterized by the following features.

2. The drain pan is, A collection section at a predetermined depth where the collected dirty liquid gathers, A recovery pump that returns the dirty liquid from the water collection section to the filtration tank, The filtration apparatus according to claim 1, characterized by having the following features.

3. The system includes a dewatering roller that is pressed against the drive roller and rotates in accordance with the drive roller to dewater the strip-shaped filter cloth, The foam outlet is located above the normal liquid level of the dirty liquid in the filtration tank and below the lower end of the dewatering roller. A filtration apparatus according to claim 1 or 2, characterized by the above.

4. The foam outlet is formed on both of the pair of side walls. The filtration apparatus according to feature 1.

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