JPH0139805B2 - - Google Patents

Description

[Detailed description of the invention]

(Technical Field of the Invention) This invention relates to a method for effectively separating a fluid containing insoluble contaminants, particularly a fluid containing many fine particles in the contaminants, into a liquid component and a solid component. The present invention relates to a method of alternately scraping and cleaning solid matter (cake) adhering to the surface of a filter medium in a liquid separator, and a solid-liquid separator equipped with the cake scraping means and cleaning means described above. (Technical background of the invention and its problems) Cutting oil waste fluid, polishing waste fluid, etc. discharged from cutting machines, polishing machines, etc. contain relatively high concentrations of insoluble impurities and particles with fine diameters. It often contains a lot of. For this reason, conventional general filtration equipment cannot be applied, and various solid-liquid separators are used, but since the entire equipment is complex and large-scale, it is said that they are provided for each machine or each series. It was common for an entire factory to have one unit. The equipment used for each machine or line was a centrifugal separator, a separator using magnetic force, or a combination of these with a conventional filter, but the processing capacity and separation capacity were limited. However, the running cost was low and the running cost was high. In particular, it is extremely inadequate for the purpose of collecting and reusing expensive cutting oils, polishing fluids, etc., and requires further precision filtration in order to be reused. Ta. Therefore, we developed a solid-liquid separator (patent application filed in 1983) that has a simple, inexpensive, and compact structure that corrects the above-mentioned drawbacks.
-140289), but the above-mentioned solid-liquid separator also requires that the average particle size of the contaminants in the solid-liquid mixed fluid (hereinafter abbreviated as stock solution) containing many contaminants is 1 micron (μm) or less. In some cases, the solid content that is uniformly layered on the surface of the filter medium as it is used cannot be removed simply by scraping, especially when the filter medium is deformed during molding, expanded by liquid, or otherwise distorted. In some cases, it is difficult to perform a certain amount of scraping work, and the processing capacity is reduced, and eventually even the solid-liquid separation work and the work related to this equipment are stopped and interrupted. It will be necessary to remove it from the surface and recreate the throughput. The above-mentioned filter media regeneration work stops and interrupts not only the solid-liquid separation equipment but also the work related to this equipment. It has been pointed out that it is unsuitable for work, not only hinders the smooth working process, but also reduces the original workability due to the extra work process of regenerating the filter medium. (Object of the invention) This invention was made in view of the above-mentioned circumstances, and the object of this invention is to provide a solution that can be used for a long period of time even when the average particle size of contaminants in the stock solution is 1 micron (μm) or less. It is an object of the present invention to provide a filter medium cleaning method for maintaining stable processing capacity, and a solid-liquid separator having the above-mentioned filter medium cleaning means. (Summary of the Invention) This invention provides a method for sealing both ends of a cylindrical filter medium made of a hard porous material having continuous pores with flanges connected to a rotating shaft, and maintaining the inside of the filter medium in a reduced pressure state using a decompression means. is rotated, the solid-liquid mixed fluid containing the impurities is sprayed on the surface of the filter medium, and the liquid content is suctioned and removed due to the pressure difference, so that the solid content accumulates in a layer on the surface of the filter medium, and the side part The solid content and the liquid content are separated by scraping off the accumulated layer with a scraping means provided along the filter, and the reduced pressure state is periodically released, and the scraping means is brought into contact with the surface of the filter medium. The solid content layered on the surface of the filter medium is cleaned for a predetermined period of time by a cleaning means, and the solid content and liquid content are separated by continuously maintaining stable processing capacity of the filter medium for a long time. This is a solid-liquid separator and its filter medium cleaning method that can shorten the time. (Embodiments of the Invention) The solid-liquid separator according to the present invention limits the properties of the filter medium to hard ones, thereby eliminating the drawbacks of conventional solid-liquid separators. That is, a conventional solid-liquid separator using a porous body uses a soft porous body, such as a belt-like one, as a filter medium, and removes the liquid component by means of squeezing or pressing.
Since it is of the type that separates the solid content contained, the apparatus is extremely large-scale and inefficient, and it has been difficult to obtain a compact and highly efficient apparatus. In addition, when a soft filter medium is used in a type of device that uses differential pressure to remove liquid content as in this invention, a perforated cylindrical frame made of metal or plastic is used as the center, and the filter medium is wrapped around the outer periphery. It requires layering and requires time and effort to prepare. However, when using a hard material as in the present invention, for example, if one uses an integrally molded material, there is no need for a core and it can be attached and taken off as is, and when creating a filter material, there is no need for the complexity of winding layers and pasting. It is possible to omit it. Furthermore, in the case of soft filter media,
There are also problems with dimensional stability such as deformation and blinding due to suction during use, and the ability to scrape off the layered buildup that forms on the surface of the filter medium is not sufficient, so it cannot withstand long-term continuous operation. However, if a hard filter medium is used as in the present invention, this problem can be completely solved. Furthermore, there is less damage to the material itself, and the period of use can be significantly extended. The hard porous body having continuous pores mentioned here may be a humonica-like structure having countless pores that are continuous linearly from the outer layer to the inner layer, but it may also be a three-dimensional network-like structure. It is more preferable that the pores have a structural organization and each pore is irregularly continuous. In addition, the materials include porous ceramic, sintered metal porous body, metal wire mesh laminate, sintered resin porous body, hard resin porous body,
Alternatively, a porous fiber material made of laminated non-woven fabric or yarn may be treated with a thermosetting resin and cured.
A hard resin porous body is particularly suitable from the viewpoint of ease of controlling the pore diameter, light weight, etc. The hard resin porous body includes, for example, a cured body of urethane resin, a porous body of polyvinyl formal resin treated and cured with a thermosetting resin, a porous body made of a thermosetting resin, etc. Not particularly limited. However, even in a solid-liquid separation device using a hard porous filter medium as described above, the pore size of the filter medium must be set to be less than the above particle size, especially when the stock solution contains fine particle contaminants with an average particle size of 1 μm or less. However, since the particle size is very fine, some of the particles may be trapped in the filter medium, or due to deformation of the filter medium during molding, expansion by liquid, or other distortions, the scraping means and the filter medium may be damaged. A layer of cake remains unevenly in the slight gap between the filter and the filter, and this uneven layer of cake on the surface of the filter medium reduces the surface area of the filter medium and increases the water flow pressure drop, which results in stable solid-liquid separation. It becomes difficult. In addition, if the cake is uniformly stacked on the surface of the filter medium, it is difficult to remove it by the scraping means alone, and the heat of the stacked cake layer gradually increases, reducing the throughput. It will end up being put away. Therefore, in order to solve the above-mentioned problems, even if the contact pressure of the scraping means to the filter medium is increased, uneven contact will not only cause vibrations but also cause wear and tear of the scraping means. It can also cause Therefore, a means for cleaning the cake that cannot be removed by the scraping means is provided, and by performing the scraping and cleaning alternately, the solid-liquid separator can maintain stable filtration performance for a long time. Become. Next, embodiments of the present invention will be specifically described with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of the present invention. In this figure, 1 is a cylindrical filter medium having pores (filtration holes) with a diameter of 0.1 to 200 μm on its outer peripheral surface. The cylindrical filter medium 1 is sealed with disk-shaped side plates 5A and 5B in the axial direction, and a hollow rotating shaft 4 is inserted through the center hole thereof. Since the filter medium 1 has continuous pores and has affinity, the liquid in the stock solution smoothly permeates into the inside due to capillary action. As a result, the filtration resistance becomes small, and the liquid component in the stock solution can be easily sucked into the cylindrical chamber of the cylindrical filter body 1 without reducing the internal pressure of the cylindrical filter medium 1 that much. Further, the other end of the cylindrical filter medium 1 is connected to the main body via a rotating support shaft 2, and a pulley 11 is provided in the middle of the hollow rotating shaft 4, and a pressure reducing mechanism 13 is provided.
A belt 14A is wound between the drive wheel 14 and the pressure reducing mechanism 13, and a motor 12 is connected to the pressure reducing mechanism 13. The cylindrical filter medium 1 is installed so that its lower half is almost buried in the stock solution tank 7, and as shown in FIG. A undiluted solution drain port 3 with a brush attached on the same side of the shaped pipe is connected via an air cylinder 32 so that the tip of the brush 31 comes into pressure contact with the surface of the filter 1 during filter media cleaning. The liquid is provided at a predetermined distance from the surface of the filter medium. Here, during the filtration work, the stock solution 9 supplied from the stock solution supply port 32 is
1 is discharged from the liquid drain port 30 and sprayed, and the stock solution 91 that is not sucked is received in the stock solution tank 7. On the opposite side of the filter medium 1, there is a scraper 6 as a scraping means for scraping off the cake 94 formed on the surface of the filter medium 1.
An air cylinder 62 is provided so that its tip is in pressure contact with the surface of the filter medium 1 during filtration work, and separated from the filter medium 1 during cleaning of the filter medium. 9
A container 61 for receiving 2 is installed. Also,
A suction pump 81 is connected to the end of the hollow rotating shaft 4 via a pipe 8, and the liquid component sucked from the cylindrical chamber of the filter medium 1 is stored in a container (not shown). To explain the outline of filtration and cleaning of the filter medium in such a solid-liquid separator, drain holes 30 are formed on the filter medium 1.
When the stock solution 91 is supplied, the liquid component is absorbed into the cylindrical filter medium 1 by the suction force of the suction pump 81.
The cake 92 is sucked into the cylindrical chamber of the cylindrical filter medium 1, and the cake 92 accumulates in layers on the outer peripheral surface of the cylindrical filter medium 1. The liquid component sucked into the cylindrical filter medium 1 is discharged into the external container via the pipe 8, and the cake 92 accumulated on the outer peripheral surface of the cylindrical filter medium 1 is removed into the container 61 by the scraper 6 provided along the side surface. It is scraped off, thereby performing solid-liquid separation. That is, the stock solution 91 is drained from a drain hole 30 connected to a drain pipe of a cutting machine, a polishing machine, etc.
is discharged and sprinkled on the upper surface of the filter medium 1. The filter medium 1 is maintained at a reduced pressure inside through the pipe 8 and the hollow rotating shaft 4 by a suction pump 81 such as a liquid pump, a vacuum pump, or an ejector with high self-priming capacity, and is driven by a motor 12. Since it is gently rotated in the direction of arrow A, the liquid component of the liquid sprayed on the surface of the filter medium 1 passes through the filter medium 1 due to the suction action, and is then passed through the hollow rotary shaft 4 as a liquid absorption hole to the outside of the system from the pipe 8. The solids remain on the surface and form a stable cake layer. The layer of cake 92 is scraped and removed by the scraper 6, and at the same time the surface of the filter medium 1 is renewed in this area. The stock solution tank 7 is a tank that receives surplus stock solution 91, and has a structure in which the lower part of the cylindrical filter medium 1 is accommodated, and when stock solution 91 is present in this part, it is sucked and separated by the same action. will be carried out. Note that an automatic valve (not shown) may be provided at the bottom of the stock solution tank 7 to return the excess stock solution 91 to its original state. However, just by pressing the scraper 6 as described above, the cake 92 layered on the surface of the filter medium 1 cannot be completely removed as described above, and in particular, as described above, the contaminants in the stock solution 91 cannot be completely removed. When the average particle size of the filter medium 1 is less than 1 μm, a slight cake layer is left behind on the surface of the filter medium 1, which grows as the operation continues for a long time, reducing the filtration capacity of the solid-liquid separator mentioned above. You will end up letting it happen. Therefore, using the external view showing the main parts of the present invention shown in FIG. 3 and the time chart shown in FIG. Explain how to clean the cake layer. In FIG. 3, during the filtration of the stock solution 91 as described above, the brush drain port 3 is moved in the direction G in the figure by the air cylinder 32 and fixed at a position where it does not come into contact with the filter medium 1, The supplied stock solution 91 is sprayed onto the surface of the filter medium from the drain port 30, while the scraper 6 is moved in the direction D in the figure by the air cylinder 62, and its tip is pressed against the surface of the filter medium and is laminated on the surface of the filter medium. The removed cake 92 is now removed. Here, in order to suction the liquid portion of the stock solution, the inside of the filter medium 1 must be kept in a reduced pressure state by the suction pump 81, and the vacuum valve 10 is closed. Therefore, as mentioned above, the layer of cake 92 that could not be completely removed by the scraper 6 is removed on the surface of the filter medium.
When the adsorption force is working inside, and the layer gradually grows and the processing capacity of the solid-liquid separator decreases, the solid-liquid separator stops filtration work to restore the processing capacity, and the filter media A cleaning operation is started. That is, first, the supply of the stock solution 91 is stopped, the above is stopped, the suction pump 81 is stopped in order to make it easier to peel off the solid content layered on the surface of the filter medium, and at the same time, the vacuum valve 10 is interlocked to remove the atmospheric air. By opening, the pressure difference in the inner material of the filter medium 1 disappears. Then, the scraper 6 is moved back in the direction E in the figure by the air cylinder 62, and its tip is separated from the filter medium 1. On the other hand, the brushed drain port 3 is moved forward in the direction B in the drawing by the air cylinder 32, and the brush is brought into pressure contact with the surface of the filter medium 1. Even during the above-described operation, the filter medium 1 continues to rotate in the direction A shown in the drawing by the above-mentioned means, and when the brush is pressed against the surface of the filter medium 1, the cake layer that has not been removed by the scraper 6 is cleaned. When the cleaning work is carried out for a predetermined period of time, the filtering capacity of the filter medium 1 is reproduced. Therefore, the vacuum valve 10 is closed and the suction pump 81 is operated in conjunction with the vacuum valve 10, and at the same time, the brushed drain port 3 is moved back in the direction C in the figure by the air cylinder 32, and is removed from the surface of the filter medium. On the other hand, the scraper 6 is moved forward in the direction D in the figure by the air cylinder 62, its tip is pressed against the surface of the filter medium 1, and when the stock solution 91 is supplied, the above-mentioned filtration work is reproduced. By performing the above-mentioned filtration work and filter medium cleaning work alternately and regularly and automatically, stable filtration processing capacity is maintained at all times, and the above-mentioned contaminants with an average particle size of 1 μm or less are contained. A solid-liquid separator capable of stably filtering even a stock solution for a long period of time will be provided. Next, embodiments of the solid-liquid separator of the present invention will be specifically described according to Examples. EXAMPLE Table 1 shows the results of a filtration test conducted on a cylindrical filter medium of a solid-liquid separator with and without cleaning using the cleaning means of the present invention.
The filtration stock solution is a polishing liquid (concentration of approx.
2000ppm), and the filter medium has an outer circumference of 300 mmφ and an inner circumference of 240 mm.
A phenol porous body with an average pore diameter of 15 μm and a size of mmφ and cylindrical length of 300 mmφ was used, the rotation speed of the filter medium was 15 rpm, and the pressure inside the filter medium was reduced to 300 Torr by a suction pump.

[Table] (Modified example of the invention) In the above embodiment, the filter medium cleaning brush and the stock solution drain port were provided on the same member, but each may be provided independently. In that case, only the filter medium cleaning brush is the moving means. Needless to say, it is sufficient to have the following. In addition, in the above embodiment with the brush, the suction pump 81 can be used as the drive source for the air cylinders 32 and 62 for moving the drain port 3 and the scraper 6. For example, the suction pump 81 can be During suction, the air cylinder 32 is
For example, the air cylinder 62 is piped so as to move in the direction D shown in the figure, and when the suction pump 81 is stopped and the vacuum valve 10 is opened during cleaning, the air cylinder 62 moves in the direction B and E shown in the figure, for example. A spring or the like may be provided. (Effects of the Invention) According to the solid-liquid separator and its filter medium cleaning method of the present invention, as described above, cakes stacked on the surface of the filter medium can be shaken off, and cakes that cannot be removed by dusting alone can be removed. Since cleaning is carried out alternately, the filter media is regularly regenerated and stable filtration performance can be maintained for a long period of time, which not only shortens the processing time of undiluted solution but also allows cleaning of filtrate from many filtration undiluted solutions. can be obtained at low cost and through a large amount of processing. Currently, unit operations such as solid-liquid separation of polishing waste fluid or oil filtration used in electric discharge machines are problems, but by using the solid-liquid separation and filter media cleaning method of this invention, solid-liquid separation can be achieved. This has the effect of significantly reducing the cost required for separation equipment and filtration.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing an embodiment of the present invention, Fig. 2 is a cross-sectional view showing the main parts of the drain port and filter medium cleaning section of the invention, and Fig. 3 is for explaining the cleaning method of the invention. FIG. 4 is a perspective view showing the main parts of the invention, and FIG. 4 is a time chart showing the operating method of the invention. 1... Filter material, 3... Drain port with brush, 6... Scraper, 7... Stock solution tank, 8... Suction pipe, 1
0... Vacuum valve, 30... Drain port, 31... Filter medium cleaning brush, 32, 62... Air cylinder.

Claims (1)

[Scope of Claims] 1. A cylindrical filter medium made of a hard porous material having continuous pores, a side plate connected to a rotating shaft and rotatably sealing both ends of the filter medium, and formed of the filter medium and the side plate. Due to the pressure difference between the pressure reducing means that maintains the space in a reduced pressure state, the means for dispersing the solid-liquid mixed fluid containing impurities onto the surface of the filter medium, and the pressure reducing means, only the liquid portion of the solid-liquid mixed fluid is inside the filter medium. a scraping means for scraping the solids accumulated in a layer on the surface of the filter medium along the side surface of the filter medium; and a surface of the filter medium that cannot be completely removed by the scraping means. In order to remove the solid content on the surface of the filter medium, the reduced pressure state is released, the scraping means is moved to a position where it does not come into contact with the filter medium, and the solid content on the surface of the filter medium is cleaned along the side surface of the filter medium. 1. A solid-liquid separator comprising: a cleaning means for cleaning the solid-liquid separator; 2. A cylindrical filter medium made of a hard porous body having continuous pores is sealed at both ends with flanges connected to a rotating shaft, and the filter medium is rotated while the inside thereof is maintained in a reduced pressure state by a pressure reducing means, and the The solid-liquid mixed fluid containing impurities is sprayed and the liquid content is suctioned and removed by a pressure difference, thereby causing the solid content to accumulate in a layer on the surface of the filter medium, and a scraping means provided along the side surface. The solid content and the liquid content are separated by scraping off the accumulated layer with a holder, and further, the reduced pressure state is periodically released, the scraping means is moved to a position where it does not come into contact with the surface of the filter medium, and the The solid content layered on the surface is cleaned by the cleaning means for a predetermined period of time, and the processing capacity of the filter medium is maintained by alternately performing scraping of the solid content by the scraping means and cleaning by the cleaning means. A method for cleaning a filter medium of a solid-liquid separator, characterized by: