JPH0521604B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a filtration method and apparatus for continuously removing impurities from a liquid containing soil, sand, or other impurities to obtain a clean liquid. .

(Prior Art) Conventionally, in order to separate impurities from a liquid containing soil, sand, or other unspecified impurities and obtain a clean liquid, separation by sedimentation, separation by a general filter, centrifugation, etc. , separation using a filter press, etc. have been carried out, and further treatments have been carried out using a combination of these methods. In general, appropriate equipment and methods are used depending on the type, size, concentration, or processing amount of the impurities contained. For example, there is a large difference in specific gravity with the liquid,
When processing a large amount of liquid containing large amounts of contaminants with large particle sizes, a method using a sedimentation tank is used, and if gravity difference cannot be used, separation using a filter medium or separation using a filter press is used. It is being done. Furthermore, it is also common practice to obtain a clear liquid by a multi-stage method that combines these methods.

(Problems with the conventional technology) However, when the type, particle size, shape, or concentration of impurities contained in the liquid varies widely, and the liquid needs to be treated continuously, the conventional technology cannot handle the problem. is not enough. That is, even when a sedimentation tank is used, if the proportion of fine particle contaminants or contaminants with low specific gravity is high, precipitation will not occur efficiently. Also, when using a cartridge type filter,
When the concentration of impurities increases, the eyes become clogged quickly, shortening their lifespan and being unable to handle high-concentration liquids. Centrifugal separation or filter press, etc., do not have a large throughput, are discontinuous, and are disadvantageous in terms of cost, so they can only be used with special liquids and cannot be called general methods. Ta.

From the above, the reality is that there is currently no suitable method or apparatus for solid-liquid separation of liquids in which the type, size, shape, and concentration of contaminants are likely to change, and it is difficult to cope with this problem.

(Purpose of the Invention) In view of the problems of the above-mentioned prior art, the present inventor has conducted extensive research, and has developed a method of using a porous body having a continuous network structure as a cylindrical filter medium, completely immersing the filter medium in a liquid, and The above problem is solved by drawing out only the liquid part by reducing the pressure and removing the buildup on the surface of the filter medium with a rotating brush that is completely immersed in the dispersion liquid, keeping the surface clean at all times. The purpose of the present invention is to provide a method and apparatus for continuously removing impurities from a liquid and obtaining a clear liquid.

(Means for achieving the purpose) The above purpose is to rotate the cylindrical filter medium completely immersed in the dispersion while continuously supplying the dispersion containing impurities to the liquid tank from the supply nozzle. At the same time, a negative pressure generator was operated to reduce the pressure inside the cylindrical filter medium, and the liquid in the dispersion was sucked into the cylindrical filter medium, thereby closing the open surfaces at both ends of the cylindrical filter medium. The liquid sucked through the hollow part of the hollow drive shaft connected to one of the filter medium lids is discharged to the negative pressure generator side, and the liquid is completely absorbed into the dispersion liquid by the device provided in contact with the surface of the cylindrical filter medium. A rotating brush that rotates while immersed removes a thin layer of impurities accumulated on the surface of the cylindrical filter medium, and continuously or intermittently removes the impurities that have settled at the bottom of the liquid tank. This is achieved by a liquid filtration method in which the impurity-containing dispersion is continuously filtered and purified by discharging it out of the system.

In addition, the above purpose is to provide a liquid tank to which a dispersion containing impurities is supplied, and a mixture of a polyvinyl acetal resin and a phenolic resin that is rotatably supported within the liquid tank and has continuous fine pores. a cylindrical filter medium having a three-dimensional network structure; a hollow drive shaft for rotating the filter medium that is connected to one filter medium lid that closes both open ends of the cylindrical filter medium and communicates with the inside of the cylindrical filter medium; a negative pressure generating device connected to one end of the hollow drive shaft to reduce the pressure inside the cylindrical filter medium; and a circuit for removing a layer of contaminant accumulation installed at a position where it slides and rotates on the surface of the cylindrical filter medium. a moving brush; an extraction pump provided at the bottom of the liquid tank;
This is accomplished by a liquid filtration device that operates while the cylindrical filter medium and the rotating brush are completely immersed in the dispersion liquid in a liquid tank.

If the contaminants are sticky and difficult to remove with a drive brush alone, a scraping plate made of metal, hardened plastic, or ceramic can be installed and pressed against the filter medium with a pressure spring to remove the accumulated thin layer. Continuous removal is also effective.

The method and device of the present invention are suitable for solid-liquid separation of dispersion liquids, where the type, shape, size, or concentration of impurities constantly fluctuates, and which is difficult to track with general separation devices or filtration devices. It has excellent ability to follow concentration fluctuations during operation, and fully demonstrates its characteristics. That is, for example, it is necessary to wash collected gravel or agricultural products with a large amount of washing water before using or shipping them to ensure that the soil, organic matter layer, or fragments thereof adhering to the surface are removed. Regardless of whether the large amount of water required for cleaning is to be recovered and reused or treated as wastewater, it is necessary to remove impurities and purify it. Furthermore, it is absolutely necessary to reuse machine oil, cleaning oil, etc. used in grinding machines, polishing machines, electric discharge machines, etc. after removing impurities and purifying them. In the former case, the type and amount of soil adhering to agricultural products differs depending on the place of production and type of agricultural product, and in the latter case, the type, shape, and concentration of contaminants also vary significantly depending on the object to be processed and the processing method. . When treating these liquids, the method and apparatus of the present invention can be used in a wide range of applications, irrespective of the type, shape, size, and concentration of contaminants. Moreover, since the surface of the filter medium used is constantly renewed by an attached device, it has a long life and can be used continuously without any problems within a practical range. Furthermore, the throughput can be adjusted freely by appropriately changing the surface area of the filter medium, that is, the diameter and length of the cylinder, or the number of cylinders. This can be done by freely changing the .

As the dispersion liquid containing impurities is continuously supplied and the liquid portion is continuously suctioned and removed, the concentration of impurities in the liquid tank increases over time, making separation difficult. However, if the specific gravity of the impurities is higher than that of the liquid, they will settle at the bottom of the liquid tank, so they can be removed from the system at any time using a extraction pump. Furthermore, if the specific gravity of the impurities is low and they float in the upper layer of the liquid tank, the upper layer may be allowed to overflow and the concentrated liquid may be removed from the system. However, in this case, it is preferable to provide the stock solution supply hole near the bottom of the liquid tank. Furthermore, in the case of contaminants that neither settle to the bottom nor float to the top, an appropriate control sequence should be established to remove the contents of the liquid tank when the concentration of the liquid in the liquid tank becomes higher than the standard value. It is also effective to perform operations such as discharging everything.

By the way, if the type of liquid is water or simple mineral oil, there is no problem, but if the type of liquid is acids, organic solvents, alkalis, or corrosive solvents, the filter medium may be a laminate of cotton cloth or felt. If it is the case, it is not suitable because it is easily damaged and deteriorated. Porous materials made from metal are also good, but they have poor durability against acids and are difficult to obtain with a suitable pore structure. Furthermore, those made of ceramics such as chinaware have the disadvantage that it is difficult to obtain a suitable size and that they are easily broken or damaged during use. The most preferred in the present invention is a mixture of polyvinyl acetal resin and phenolic resin, which has a three-dimensional continuous fine pore network structure that is extremely suitable for achieving the object of the present invention. The structure is easily obtained and has appropriate hardness and toughness, and is a filter medium described in Japanese Patent Application No. 60-90430 filed by the present applicant, that is, polyvinyl acetal. A cylindrical filter medium made of a mixed resin of a phenolic resin and a phenolic resin is used.

(Embodiments of the Invention) Next, specific examples of the present invention will be described with reference to the drawings.

FIG. 1 is an external structural diagram of the liquid filtration device of the present invention;
FIG. 2 is a schematic plan view thereof, and FIG. 3 is a partially cross-sectional side view of the structure. The cylindrical filter medium 3 is held inside the liquid tank 2 with its open ends sealed by filter medium lids 12a and 12b shaped to engage with the cylindrical filter medium 3.
The filter medium lid 12a is connected to the hollow drive shaft 6,
The hollow drive shaft 6 is rotated by the motor 5, and the filter medium 3
It is designed to rotate. In addition, the filter medium lid 12
b receives the rotation of the hollow drive shaft 6 through the filter medium 3, and has a structure that allows it to rotate without resistance as the filter medium 3 rotates. The inside of the hollow drive shaft 6 is hollow, and communicates with the hollow space inside the filter medium 3, and the opposite side thereof is communicated with the negative pressure generator 4 via the rotary joint 7 and the pipe 18. By operating the negative pressure generator 4, the inside of the filter medium 3 is brought into a negative pressure state. A rotary brush 13 is arranged so as to be in contact with the surface of the filter medium 3, and the rotation of this rotary brush 13 is much better than that of the drive shaft 6, but a completely different drive device is installed separately. Good too. Further, the rotating direction of the rotating brush 13 may be the same direction as the rotation of the filter medium 3 or the opposite direction, and its speed does not need to be the same as the surface speed of the filter medium 3, but rather a surface speed faster than that. It is preferable to rotate.
The shaft connected to the filter media lids 12a and 12b is connected to the liquid tank 2.
The mounting portions have a structure that prevents liquid leakage by means of water sealing devices 8a and 8b, respectively. Further, a withdrawal pump 16 is provided at the bottom of the liquid tank 2 for discharging the precipitated high concentration sludge 19 out of the tank. This pump 1
6 shall be operated manually or automatically as necessary.

In such a structure, the filter medium 3 is replaced as follows. That is, the adjusting shaft 9 connected to the filter medium cover 12b is threaded on the opposite side of the filter medium cover 12b, and is fitted into a corresponding female screw base 10, and is rotated by the rotation of the handle 11 provided at the end. It is movable in the left and right directions in the figure. When replacing the filter medium 3, turn the handle 11 and remove the filter medium lid 12b.
is moved to the handle 11 side, the filter medium 3 and the filter medium cover 12b are separated, and the filter medium 3 is removed.
After replacing the filter with a new one, rotate the handle 11 in the opposite direction until the filter is completely fitted.
Further, the entire attachment/detachment structure may be of an air cylinder type using air pressure. On the other hand, when it is necessary to process a large amount of liquid, it is also possible to increase the processing flow rate by enlarging the liquid tank 2 and incorporating a plurality of filter media 3 instead of one.

In this way, the surface of the filter medium 3 is constantly cleaned by the action of the rotating brush 13, and the structure is such that clogging does not easily occur. However, there are cases where the rotating brush 13 alone is insufficient in dealing with the processing liquid. It is also effective to provide the scraping plate 14 at a position where it is completely immersed in the dispersion liquid. This scraping plate 14 has an edge-shaped tip and is pressed against the surface of the filter medium 3 by a spring 15.
It is designed to effectively scrape off the solid layer (cake) adhering to the surface.

Next, an embodiment of the liquid filtration method of the present invention will be described with reference to the drawings. A dispersion liquid containing impurities is continuously supplied from a nozzle 1 to a liquid tank 2. The filter medium 3 is rotated at a predetermined speed while completely immersed in the dispersion liquid in the liquid tank 2, and the inside of the filter medium 3 is maintained in a reduced pressure state by the negative pressure generator 4, so that the filter medium 3 is completely immersed in the dispersion liquid in the liquid tank 2. The liquid portion is sucked through the porous structure of the filter medium 3, taken into the internal cavity of the filter medium 3, and further discharged through the tube 18 toward the negative pressure generating device 4. When the liquid is sucked, contaminants are also attracted, but the contaminants remain on the surface of the filter medium 3. The contaminants attracted to the surface of the filter medium 3 gradually form a layer and begin to block the surface of the filter medium. In order to remove this cake layer and re-disperse it in the liquid, the rotating brush 13 is pressed and rotated to remove the filter medium 3.
Scratch the surface of the product to constantly damage the surface layer and prevent it from forming a cake layer. If the specific gravity of the foreign matter is high and the size is large, it will settle to the bottom of the liquid tank 2 due to its own weight, and the foreign matter caught on the filter surface and scraped off by the rotating brush 13 will also fall to the bottom at the same time. It's sinking down. If the concentration of impurities in the liquid tank 2 increases and the sediment layer 19 also thickens, the device cannot operate normally, so the extraction pump 16 provided at the bottom is operated to discharge the sediment layer, that is, the concentrated sludge. It is necessary.

In this way, only the clear liquid portion is continuously separated from the dispersion liquid, and the ability of the filter medium 3 does not decrease over time, so a constant flow rate can be obtained.
It also eliminates the need for short-term filter media replacement, making extremely effective filtration possible.

(Effects of the Invention) The effects of the method and apparatus of the present invention are that only a clean liquid portion can be continuously separated from a dispersion liquid that is continuously supplied, and that a constant flow rate can be obtained without decreasing its performance. It will be done. In other words, during actual operation, no complicated maintenance is required, unmanned operation is possible, and the liquid can be recovered and reused as necessary. Furthermore, it is possible to respond extremely flexibly to changes in the properties of the dispersion, especially to changes in the concentration of impurities. The operation is carried out almost irrespective of the concentration of the dispersion liquid, and even if there is a large fluctuation in the concentration, the apparatus will not be clogged or stopped due to it. Further, there is no particular problem with variations in the amount of the dispersion liquid.
In other words, it is different if the amount exceeds the capacity, but if the supply is expected to be stopped or to become extremely low, install a level meter in the liquid tank to detect the liquid level and operate the device. This can be done by turning on and off. This makes it possible to separate dispersions, which has been extremely difficult to do in the past, and the range of its utility is wide and its effects are extremely significant.

In addition, the cylindrical filter medium and rotating brush operate while completely immersed in the dispersion containing impurities supplied into the liquid tank, so the filtration area of the filter medium is large, improving filtration efficiency, and the dispersion liquid The cleaning work on the surface of the filter medium can be easily performed compared to the method that removes the accumulated layer of contaminants attached in a solidified state to the surface of the filter medium exposed outside the surface.

In addition, the cylindrical filter material is made of a mixture of polyvinyl acetal resin and phenol resin, and the three-dimensional network structure has a smooth surface and excellent durability, so the layer of accumulated contaminants can be removed. This also occurs very smoothly, increasing the service life of the cylindrical filter medium.

[Brief explanation of the drawing]

FIG. 1 is an external structural diagram of the apparatus of the present invention, FIG. 2 is a schematic plan view thereof, and FIG. 3 is a partially sectional side view. DESCRIPTION OF SYMBOLS 1...Liquid supply nozzle, 2...Liquid tank, 3...Cylindrical filter medium, 4...Negative pressure generator, 5...Motor, 7
...Rotary joint, 8 ...Liquid tank water seal section, 9
... Adjustment shaft, 10 ... Female screw head, 11 ...
Handle, 12a, 12b... Filter media lid, 13...
Rotating brush, 14... scraping plate, 15... spring, 16... extraction pump, 17... dispersion liquid, 18... tube, 19... precipitate.

Claims (1)

[Scope of Claims] 1. While continuously supplying a dispersion containing impurities to a liquid tank from a supply nozzle, a cylindrical filter medium is rotated while being completely immersed in the dispersion, and a negative pressure generating device is provided. is operated to reduce the pressure inside the cylindrical filter medium, and the liquid in the dispersion is sucked into the cylindrical filter medium, and the cylindrical filter medium is connected to one filter medium lid that closes both open ends of the cylindrical filter medium. The liquid sucked through the hollow part of the hollow drive shaft is discharged to the negative pressure generator side, and the shaft is provided in contact with the surface of the cylindrical filter medium and rotates while completely immersed in the dispersion liquid. A rotating brush removes a thin layer of contaminants accumulated on the surface of the cylindrical filter medium, and continuously or intermittently discharges the contaminants deposited at the bottom of the liquid tank out of the system. A liquid filtration method characterized by continuously filtering and purifying the dispersion containing impurities. 2. In addition to the rotary brush, a scraping plate whose tip is circumscribed on the surface of the cylindrical filter medium and is completely immersed in the dispersion liquid is used to continuously scrape off the thin layer of impurities. A liquid filtration method according to claim 1. 3. A liquid tank to which a dispersion containing impurities is supplied, and a three-dimensional network structure rotatably supported within the liquid tank and made of a mixture of polyvinyl acetal resin and phenolic resin and provided with continuous fine pores. a cylindrical filter medium having a body; a hollow drive shaft for rotating the filter medium that is connected to one filter medium lid that closes both open ends of the cylindrical filter medium and communicates with the inside of the cylindrical filter medium; and one end of the hollow drive shaft. a negative pressure generating device connected to the cylindrical filter medium to reduce the pressure inside the cylindrical filter medium; a rotating brush installed at a position where it rotates in sliding contact with the surface of the cylindrical filter medium for removing a layer of accumulated contaminants; A liquid filtration device, comprising: a withdrawal pump provided at the bottom of a tank, wherein the cylindrical filter medium and the rotating brush operate in a completely immersed state in the dispersion liquid in the liquid tank. 4. The liquid filtration device according to claim 3, further comprising, in addition to the rotary brush, a scraping plate whose tip is circumscribed on the surface of the cylindrical filter medium and completely immersed in the dispersion liquid.