Rotor for generating vortex water flow, and filtering apparatus employing the same

Disclosed are a rotor for generating vortex water flow that creates shear intensity for removing solid material adhered to the separation membranes during the processing of water containing pollutant material, and a filtering apparatus employing the same. The rotor consists of a first rotor having first blades and a second rotor having second blades. The first and the second blades are extended in a radial direction from a rotational axis thereof, and are disposed at positions different from each other in the rotational axis direction. The first blades and the second blades have widths different from each other in a circumferential direction around the rotational axis, or disposed at positions different from each other in a circumferential direction. Protrusions can be attached on outer surfaces of the first blades and/or second blades. The pollutant material adhered to the separation membrane can be removed effectively since various types of vortex water flow are generated over wide range, and the energy loss of the filtering apparatus is reduced.

CROSS REFERENCE TO RELATED APPLICATION

The present application is a 35 U.S.C. §§371 national phase conversion of PCT/ KR2005/000485, filed 23 Feb. 2005, which claims priority of Korean Patent Application No.10-2004-0016400, filed 11 Mar. 2004, which is herein incorporated by reference. The PCT International Application was published in the English language.

TECHNICAL FIELD

The present invention relates to a rotor for generating vortex water flow and a filtering apparatus employing the same, and more particularly, to a separation membrane filtering apparatus for filtering pollutant in water containing the pollutant material to a clean purified water, and a rotor for generating vortex water flow employed in the same.

BACKGROUND ART

The filtering apparatus for purifying water by filtering the pollutant in the polluted water is generally equipped with a porous membrane through which the polluted water passes. The pollutant in the polluted water is filtered by the porous membrane, by which the water passing through the porous membrane is discharged as a clean water.

The problem hardest to overcome in such a liquid-solid separation technique using the porous membrane is the abrupt declination of the liquid(or gas)-solid separation capacity of the separation membrane as the size of the pores that are the passages of the filtered liquid is reduced or the pores are blocked by the solid material adhered to the surface of the separation membrane or to the inner surface of the pores during the separation process. A variety of methods have been proposed in the past several decades in order to solve such a problem.

U.S. Pat. No. 3,437,208, Apparatus for Dynamic Filtration for Liquids, has proposed the structure that a rotary type (or fixed type) disks having blades are disposed between the piled fixed type (or rotary type) separation membranes and are rotated, thereby preventing the declination of shear intensity for the separation membranes by generating shear force for detaching the pollutant adhered to the surface of the separation membranes.

U.S. Pat. No. 4,036,759, Apparatus and System for Stabilizing the Disk element of a rotary concentrator for solids containing fluids, discloses the structure that a shoe is so mounted on the rotating part, that is, on the outer circumferential surface of the supporting plate of the rotary type disk or the rotary type separation membrane, as to rotate along the guide recess of a housing. According to such a construction, the problem occurring in the structure that the rotary type (or fixed type) disks are disposed between the piled fixed type (or rotary type) separation membranes as in the U.S. Pat. No. 3,437,208, that is, the deformation and the displacement in the shaft direction of the disk due to the pressure difference between both surfaces of the disk are prevented and therefore the stability of the system increases.

U.S. Pat. No. 5,275,725, Flat separation membrane leaf and rotary separation apparatus containing flat membranes, discloses the structure that a fixed type partitions made of flexible material are disposed between the piled rotary type separation membrane units to prevent the deformation by the pressure difference and the breakdown of the separation membranes caused by the same.

U.S. Pat. No. 5,415,781, Dynamic filter separator and separation device, and U.S. Pat. No. 5,679,245, Dynamic filter system, disclose the structure of separation apparatus having the fixed type separation membranes and the rotary type disks with blades.

In such conventional filtering apparatuses, as mentioned above, the disks are disposed between the separation membranes in order to reduce the adhesion of solid material on the surface of the membranes by generating strong shear rate on the surface of the separation membranes through the relative movement between the separation membranes and the disks. However, the shear rate on the surface of the membrane by the relative movement decreases seriously as the distance between the separation membrane and the disk becomes great. If the distance between the separation membrane and the disk becomes small in order to increase the shear rate, the separation membrane and the disk may contact with each other by the pressure difference between both sides of the disk to cause the damage on the membrane, so the precise treatment and accurate assembly are required to prevent such a problem, which may cause the increase of the manufacturing costs. Furthermore, the pressure decrease occurs as the fluid flows along the long passage formed by the piled separation membrane—disk—separation membrane structure, and the fluid has to be supplied with greater pressure in order to maintain proper filtering pressure and prevent the decrease of performance by compensating such a pressure decrease. However, that causes the increase of the driving costs and management costs, which deteriorates the economical performance of the system.

U.S. Pat. No. 6,165,365, Shear localized filtration system, and U.S. Pat. No. 6,416,666, Simplified filtration system, disclose the technique that the centrifugal force and the rotational force are applied to the fluid with the viscosity of the fluid by rotating the piled separation membranes. According to that, the movement of the fluid between the separation membranes is caused to reduce the adhesion of solid material on the surface of the membranes. Furthermore, four through sixteen, optimally eight, fixed type spokes are disposed radially between the separation membranes, which makes the pressure distribution uniform and the speed of fluid between the spokes and the membranes great to increase the shear intensity, thereby preventing the adhesion of the solid material.

The above patent describes that the spokes promote the turbulent flow phenomenon at the surface of the membranes. However, it is considered that the effect of inducing the turbulent flow is quite little, since the flow in the circumferential direction and the radial direction is laminar flow. Therefore, the spokes in the above patent only has the effects that the uniform pressure distribution is achieved in the filter pack, and the adhesion of the solid material is minimized due to the change of the speed of fluid at the surface of the membrane by the change of the volume in the space from the separation membrane.

As mentioned above, in order to minimize the adhesion of the solid material at the surface of the separation membranes, it is the best method to increase the shear rate by vitalizing the flow around the separation membranes. However, the increase of the shear rate of the fluid at the surface of the membranes merely with the change of the speed of fluid by the relative movement of separation membrane—disk—separation membrane, or separation membrane—spoke—separation membrane construction in the conventional art proposed under such a purpose is limited.

SE 451429 and SE 459475 disclose the separation apparatus having separation membrane—rotor—separation membrane construction which is different from the above separation membrane—disk—separation membrane, or separation membrane—spoke—separation membrane construction. In those patents, the rotor is shaped into not the disk but a bar, so the rotation of the rotor causes not only the shear flow but also the turbulent flow between the separation membranes. It provides low loss of pressure since the passage between the membranes is narrow in comparison with the system having the disk type rotor, and furthermore, the bar shape rotor proposed in those patents has great influence on prevention of adhesion of solid material. However, that effect is not sufficient in fact, so the regeneration process for the separation membranes has to be performed regularly.

According to the above-mentioned SE 451429, the regeneration process for the separation membranes is the process that a mechanical element such as a brush or a valve is attached on the blade of the rotor and the material adhered to the surface of the separation membrane is removed by rotating it, which has the shortcoming that the porous coating on the surface of the separation membrane is also removed during that process. In order to compensate such a shortcoming, the surface of the membrane is newly coated, however, such a mechanical separation membrane regeneration process cannot maintain the required size of the pores as desired, and the separation membrane has to be exchanged with a new one when the regeneration is not easy. The above-mentioned SE 459475 proposes the method to increase the capacity by piling up the filter units.

U.S. Pat. No. 6,027,656 proposes a separation device that does not require the mechanical regeneration process since the stronger turbulent flow is induced between the membranes with the rotor of which shape is modified from the bar shape rotor. However, stronger turbulent flow is not expected since the employed rotor merely consists of two blades. Furthermore, the speed of the rotor is a sole factor in controlling the magnitude of the turbulent flow according to the kind or status of the fluid to be processed, so it is very hard to separate various kinds of liquid of various characteristics. In order to compensate such a shortcoming, the above-mentioned patent has proposed a method to equip an ultrasonic wave or electric field generation apparatus together with the rotors having various cross sectional shapes.

As describes so far, the most effective method for preventing the most significant problem, the adhesion of foreign substance on the surface of the membranes, in the liquid-liquid or liquid-solid separation apparatus using the separation membranes is to make the shear stress at the surface of the membranes as great as possible. It is necessary to generate the turbulent flow for such a purpose, however, the method that has been proposed so far can generate the turbulent flow within a limited range. In particular, the unit in U.S. Pat. No. 6,027,653, which is expected to induce the stronger turbulent flow than the filter unit of rotary type separation membrane—fixed type spoke construction in U.S. Pat. No. 6,165,365 or than the filter unit of separation membrane—disk—separation membrane construction, employs the rotor having only two blades, so the turbulent flow is generated locally and the rotational speed has to be greater for the stronger turbulent flow.

Furthermore, although the fluid of different characteristics about the density, viscosity, etc. requires turbulent flows of different strength, the turbulent flow of desired magnitude can be achieved only by the change of the rotational speed of the rotor since the shape of the rotor is fixed. Therefore, the rotational speed has to be greater to generate the stronger turbulent flow regarding to the fluid of greater viscosity and density, which causes the increase of the required driving energy and the loss of the energy.

DISCLOSURE OF INVENTION

Technical Problem

The present invention has been proposed to overcome the above problems, and it is the object of the present invention to provide a rotor for generating vortex water flow, and a rotary type separation membrane filtering apparatus employing the same, which can generate vortex water flow having sufficient shear intensity with respect to the separation membrane with low driving energy, and also can generate optimized turbulent flow (especially, vortex water flow) that is appropriate for the separation process of the fluid of different characteristics.

Technical Solution

To achieve the above-described objects, the present invention provides a rotor for generating vortex water flow, comprising: a plurality of first blades extended in a radial direction from a rotational axis thereof; and a plurality of second blades extended in the radial direction from the rotational axis, and disposed at positions different from positions of the first blades in a direction of the rotational axis.

According to the first preferable embodiment of the present invention, the first blades and the second blades have widths different from each other in a circumferential direction around the rotational axis, and the first blades and the second blades are so disposed as to be overlapped with each other.

According to the second preferable embodiment of the present invention, the first blades and the second blades are disposed at positions different from each other in a circumferential direction around the rotational axis, and the first blades and the second blades are partially overlapped with each other.

According to the third preferable embodiment of the present invention, the first blades and the second blades are disposed at positions different from each other in a circumferential direction around the rotational axis, and the first blades and the second blades are distanced from each other in the circumferential direction. In such a situation, the first blades and the second blades are so disposed as to be distanced equally from each other in the circumferential direction.

According to the fourth preferable embodiment of the present invention, at least one of protrusion is attached on outer surfaces of the first blades and/or second blades. The protrusion is so formed as to have width varying in the circumferential direction, and for example, the protrusion is so formed as to have streamlined width in the circumferential direction, and furthermore, the protrusion is so formed as to have a rear shape curved rearward in the circumferential direction or to have a horizontal cross section of circle shape substantially. It is preferable that a plurality of protrusions are respectively attached between the first blades and the second blades, and sizes of the protrusions become greater gradually in the radial direction.

Meanwhile, the first blades and the second blades have widths same with each other in the circumferential direction, and the first blades and the second blades are disposed alternately in the circumferential direction.

According to the fifth preferable embodiment of the present invention, the first blades and the second blades are disposed so that at least a part thereof are overlapped with each other in the rotational axis direction and are disposed so as to be distanced from each other in a the rotational axis direction, and at least one protrusion is disposed between the first blades and the second blades.

Meanwhile, the rotor according to the present invention comprises: a first ring formed integrally with the first blades and disposed coaxially with the rotational axis; and a second ring formed integrally with the second blades and disposed coaxially with the rotational axis. Here, the first ring and the second ring have radiuses different from each other. Therefore, the stepwise shape of end formed by the first ring and the second ring is supported by a guide so that the rotor is not contacted with the separation membrane in the filtering apparatus.

The first rotor equipped with the first blades and the second rotor equipped with the second blades can be formed integrally in a body or can be manufactured as separate members and then are attached to each other.

Meanwhile, the filtering apparatus according to the present invention comprises: a barrel having a water inflow port, a processed water discharge port, and a condensed water discharge port; at least one of rotor disposed in the barrel and having a construction depicted in one of claims1through25; and at least one of filter tray disposed alternately with the rotors in the barrel.

The filter tray is fixed in the barrel, and has at least one of water passage port so formed as to penetrate a plane thereof. The water in the barrel can flow smoothly in the barrel through the water passage port.

The filter tray includes a supporting plate having a disk shape, a drain cloth attached on both surface of the supporting plate, and a separation membrane attached to an outer surface of the drain cloth, and the drain cloth and the separation membrane are adhered onto the supporting plate with thermosetting adhesive. Thus, the manufacturing process becomes simple.

According to the present invention, the pollutant material adhered to the separation membrane can be removed effectively since various types of vortex water flow are generated over wide range. Therefore, the efficiency of the filtering apparatus in processing the polluted water increases, and the energy loss of the filtering apparatus is reduced. Furthermore, sufficient vortex water flow can be generated with low energy even for the fluid of different characteristics such as density or viscosity.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinbelow, the preferable embodiments of the present invention will be described in greater detail with reference to the accompanying drawings.

FIG. 1is a cross sectional view of the filtering apparatus employing the rotor for generating vortex water flow according to the present invention. The present invention proposes a rotary type separation membrane filtering apparatus, and more particularly, a filtering apparatus having fixed type separation membranes and rotary type rotors.

The filtering apparatus50is comprised of a barrel60, and a plurality of filter trays70and rotors80piled up in the barrel60. The barrel60has a water inflow port61, a processed water discharge port65, and a condensed water discharge port63. The filter tray70is fixed on the inner side of the barrel60by bolts91, and the rotor80is rotatably installed in the barrel60by a rotational shaft95. The filter tray70and the rotor80have the shape of a disk, and are arranged alternately in the barrel60.

When the water containing pollutant material flows into the barrel60through the water inflow port61, the pollutant material in the water is filtered by the filter tray70to a clean processed water and then is discharged outside through the processed water discharge port65, and the condensed water in which the pollutant material is condensed is discharged outside of the barrel60through the condensed water discharge port63. In such a situation, the rotors80are rotated continuously by a motor (not shown) that rotates the rotational shaft95during the filtering operation of the filtering apparatus50, and the solid state pollutant material adhered to the membrane of the filter tray70is removed from the membrane by the shear force generated in that situation. The removed pollutant material is discharged outside through the condensed water discharge port63while being contained in the condensed water.

FIG. 2shows the status that the filter trays70and the rotors80inFIG. 1are piled. As the filter trays70and the rotors80are arranged alternately, the filter tray70aat the upper area and the filter tray70bat the lower area constitute one filtering unit together with the rotor80disposed between them. In one filtering unit, the rotor80removes the solid state pollutant material on the membrane attached on the lower side of the upper filter tray70aand the upper side of the lower filter tray70b.

FIG. 3shows the detailed construction of the filter tray. The filter tray70is comprised of a supporting plate71having a disk shape, drain cloths73respectively attached to the upper and the lower sides of the supporting plate71, and the membranes75attached on the outer side of the respective drain cloths73. The supporting plate71is made of stainless steel, and maintains the disk shape appearance of the filter tray70. A plurality of fixing portions72fixed on the inner side of the barrel60by the bolts91are prepared at the outer edge of the supporting plate71. The membranes75filter the inflow water, and the drain cloths73supports the membranes75to maintain the outer appearance of the membranes75and simultaneously guides the filtered water toward the processed water discharge port65.

Two water passage ports79are formed on the plane of the respective filter trays70.

The water flows smoothly in the barrel60through the water passage ports79.

The basic construction and the operation of the rotary type separation membrane filtering apparatus are the same with those of the conventional art, so the detailed description about the construction of the filtering apparatus is omitted, and the construction of the rotor for generating vortex water flow according to the present invention will be described in detail hereinafter.

The rotor for generating vortex water flow according to the present invention is characterized in that it includes a plurality of first blades and a plurality of second blades arranged in positions different from each other in the rotational direction thereof. Hereinbelow, the respective embodiments that implement such a characteristic of the present invention will be described.

FIG. 4is a view showing the first embodiment of the rotor for generating vortex water flow according to the present invention, andFIG. 5is a sectional view along the line I-I of FIG.

The rotor100for generating vortex water flow according to the first embodiment of the present invention is comprised of a first rotor110and a second rotor120. An assembly ring150assembled with the rotational shaft95of the filtering apparatus50is prepared at the central area of the rotor100, and the assembly ring150is assembled with the first rotor110and the second rotor120. Accordingly, the rotor100assembled with the rotational shaft95through the assembly ring150is rotated by the rotational shaft95when the rotational shaft95is rotated.

The first rotor110has a plurality of first blades111extended from the rotational axis in the radial direction thereof. A first assembly portion115having a shape of a ring assembled with the assembly ring150is prepared at the central area of the first rotor110, and a first ring117for connecting the first blades11with each other is prepared at the outer area of the first rotor110. The first blades111, the first assembly portion115and the first ring117are formed in a body. Accordingly, the first rotor110has the overall shape of a spoke type wheel.

The second rotor110also has the second blades121, the second assembly portion125and the second ring127of which construction is the same as that of the first rotor110.

As described above, the first blades111and the second blades121are disposed at positions different from each other along the rotational axis of the rotor100. In other words, the first blades111and the second blades121are arranged consecutively in the rotational axis direction. Further, in the present embodiment, the first blades111and the second blades121are so formed as to have widths different from each other in the circumferential direction around the rotational axis, and more particularly, as shown inFIG. 5, the width of the second blades121is smaller than the width of the first blades111, and simultaneously, the first blades111and the second blades121are overlapped with each other. The first rotor110and the second rotor120having the above construction are attached to each other by an electrical welding, ultrasonic wave welding or the like. Furthermore, the first rotor110and the second rotor120can be manufactured integrally as a single member.

Meanwhile, the radius of the first ring117of the first rotor110is greater than the radius of the second ring127of the second rotor120. Accordingly, as shown inFIG. 6, which is the enlarged view of the part A ofFIG. 1including the cross section ofFIG. 4along the line I′-I′, the outer end of the rotor100has the shape of steps. (The rotor100inFIGS. 4 and 5are turned upside down for the convenience of illustration, however, the rotor100shown inFIGS. 4 and 5is disposed in the barrel60while it is turned upside down as shown inFIG. 1) As shown inFIG. 6, a guide60ais formed on the inner side of the barrel60, and the guide60ais in contact with the outer end of the rotor100so that the outer side of the first rotor110is supported by the guide60a. Therefore, the rotor100is not drooped.

FIG. 7is a view showing the vortex water flow generated between the upper filter tray70aand the lower filter tray70bwhile the rotor100according to the first embodiment of the present invention is rotating. In the present embodiment, as the widths of the upper blades and the lower blades are different from each other, the position that the vortex water is generated by the upper blades111at the rear area in the rotational direction is different from the position that the vortex water is generated by the lower blades121at the rear area in the rotational direction. Thus, more complex vortex water flow can be generated effectively in comparison with the case that the conventional rotor having the spoke of a single layer is rotated.

FIG. 8is a perspective view showing the rotor according to the second embodiment of the present invention, andFIG. 9is a cross sectional view ofFIG. 8along the line II-II. In the embodiments hereinafter, the construction of the rotor having the first rotor and the second rotor and the construction of the assembly portion and the ring at the respective sub-rotors are the same as those of the first embodiment. Therefore, only the construction of the blades is described in the illustration hereinafter.

In the second embodiment, the first blades211and the second blades221are disposed at positions different from each other also in the circumferential direction around the rotational axis of the rotor200. More particularly, the first blades211and the second blades221have the same shape and width with each other, and only the arranged positions thereof are different.

As shown inFIGS. 8 and 9, the first blades211and the second blades222are partially overlapped with each other, in other words, about half of the width thereof is overlapped. According to such a construction, as shown inFIG. 10, the position that the vortex water is generated by the upper blades211at the front area and the rear area in the rotational direction is different from the position that the vortex water is generated by the lower blades221at the front and the rear area in the rotational direction. Thus, more complex vortex water flow can be generated effectively in comparison with the case that the conventional rotor having the spoke of a single layer is rotated.

FIG. 11is a view showing the rotor for generating vortex water flow according to the third embodiment of the present invention, andFIG. 12is a cross sectional view ofFIG. 11along the line III-III.

In the third embodiment, the first blades311and the second blades321are disposed at positions different from each other also in the circumferential direction around the rotational axis of the rotor300, and furthermore,are distanced from each other in the circumferential direction. Furthermore, the first blades311and the second blades321are so disposed as to be distanced equally from each other in the circumferential direction. The width and the shape of the first blades311and the second blades321are same with each other. Therefore, as shown inFIG. 12, the first blades311and the second blades321are arranged in a zigzag manner.

According to such a construction, the vortex water flow as shown inFIG. 13is formed. As shown inFIG. 13, the respective blades311and321generate respective vortex water flows due to the shape of a spoke, and furthermore, generate large sinusoidal water flow by the zigzag arrangement thereof. Accordingly, more complex water flow is generated.

FIG. 14shows the rotor for generating vortex water flow according to the fourth embodiment of the present invention, andFIG. 15is a cross sectional view ofFIG. 14along the line IV-IV.

The rotor400of the fourth embodiment has the first blades411and the second blades421having the same construction with those in the third embodiment, and furthermore, a plurality of protrusions413and423are attached on the outer surface of the respective blades411and421. A plurality of protrusions413and423can be attached to all blades411and421, one protrusion413,423can be attached to all blades411and421, and the protrusions413and423can be attached to a part of the blades411and421selectively. When the plural protrusions413and423are attached to the respective blades411and421, it is preferable that the size of the plural protrusions413and423becomes great gradually along the radial direction of the rotor400.

The protrusions413and423can be attached to the respective blades411and421after they are manufactured as separate members, and can be formed in a body with the respective blades411and421. Furthermore, the protrusions413and423can have the widths varying in the circumferential direction, and preferably, they can have the shape that the horizontal cross section has a disk shape as shown inFIG. 14. Moreover, it is preferable that the protrusions arranged in one blade have the sizes that become greater in the radial direction of the rotor in order to generate the vortex water flow effectively.

Furthermore, as shown inFIG. 14, the protrusions413of the first blades411are attached to the upper side of the first blades411and the protrusions423of the second blades421are attached to the lower side of the second blades421. Therefore, the respective protrusions413and423are arranged to protrude inward with respect to the surface of the disk-shaped rotor400.

FIGS. 16 and 17show the vortex water flow generated by the rotor400according to the fourth embodiment of the present invention as described above, in whichFIG. 16shows the side view andFIG. 17shows the plan view.

As shown inFIG. 16, the generated vortex water flow in the side view is similar to that of the first embodiment as shown inFIG. 17at the area that the protrusions413and423are formed, and is similar to that of the third embodiment as shown inFIG. 13at the area that the protrusions413and423are not formed. Accordingly, the complex vortex water flow in which two kinds of water flows are combined is formed as shown inFIG. 16. Furthermore, as shown inFIG. 17, the vortex water flow in plan view is complex water flow in which small vortexes are generated at the rear area of the protrusions413and423. Therefore, more complex vortex water flow is generated according to such a construction.

FIG. 18shows the rotor according to the fifth embodiment of the present invention, andFIGS. 19 through 21show various modifications of the protrusions shown inFIG. 18.

In the present embodiment, the first rotor510and the second rotor520are distanced from each other in the rotational axis direction. Therefore, the first blades511and the second blades521are distanced from each other in the rotational axis direction, thereby forming a certain amount of gap between both of them. Further, the first blades511and the second blades521are formed so that at least a part of them (all the part of them in the embodiment shown inFIG. 18) are overlapped with each other.

At least one of protrusion530is formed between the first blades511and the second blades521. As in the fourth embodiment, the number and the arrangement of the protrusions530can be modified in a variety of manners. The difference from the fourth embodiment is that the protrusions530are arranged between two sub-rotors having the shapes identical to each other.

The protrusions530are formed to have width varying in the circumferential direction of the rotor500and are formed to have the streamlined width in the rotational direction of the rotor500. For example, the protrusions530acan be formed to have horizontal cross section of triangle shape as shown inFIG. 19, and the protrusions530bcan be formed to have the triangle shape basically and the rear part in the rotational direction is curved to protrude rearward as shown inFIG. 20. According to such a shape, the front part in the rotational direction undergoes the little resistance of water to result in low loss of rotational energy, and the rear part in the rotational direction generates the vortex water flow effectively. Furthermore, as shown inFIG. 21, the protrusions530ccan be formed to have the cross section of circle shape substantially. (FIGS. 19 through 21show the states that the second rotor520is disassembled in order to illustrate the shape of the protrusions clearly.)

According to such an embodiment, the vortex water flow as shown inFIG. 17which shows the vortex water flow formed by the above fourth embodiment is generated.

According to the variety of embodiments of the present invention as described above, the fluid between the surfaces of the blades in the rotating rotor and the surfaces of the fixed membranes can flow faster, so the adhesion of solid material can be prevented by the stronger shear intensity on the surfaces of the membranes. Furthermore, the vortex water flow at the rear area of the respective blades of the rotating rotor causes the sinusoidal speed distribution in the vertical and the horizontal direction with respect to the surface of the membrane at the surface of the separation membrane of the filtering plate, which can prevent the adhesion of the solid material by vitalizing the movement of the solid material near the surfaces of the membranes.

Comparing the vortex water flow generated by rotating the rotor proposed in the conventional art, U.S. Pat. No. 6,027,656, at the angular speed sufficient to generate the turbulent flow with the vortex water flow generated by rotating the rotor with multiple blades according to the present invention at the same speed, the vorticity of the rotor according to the present invention is relatively greater. In particular, the zigzag type rotor of third embodiment (FIG. 11) is superior in generating the vortex water flow with the smooth flow, and the shape of the rotor of fourth embodiment (FIG. 14) can generate vortex water flow in the circumferential direction as well as in the radial direction, so the cleaning effect can be achieved on overall area of the channel.

FIGS. 22 and 23are the experimental result tables showing the comparison result of the performance of the rotor according to the present invention with that of the bar type rotor disclosed in the above-mentioned U.S. Pat. No. 6,027,656. As shown in the figures, the multi-blade type rotor according to the present invention results in double the performance of the conventional bar type rotor under the same operation condition such as supplying pressure or operating speed, and in the aspect of the processing amount, the consumed energy is 50% through 60% of that of the bar type rotor in processing the same amount of water. That means the face that the multi-blade type rotor of the present invention shows the improved efficiency of about 300% in comparison with the bar type rotor, which is superior effect over the conventional products.

Meanwhile, the conventional filter tray has the complex sealing structure for fixing the separation membranes and the drain cloths, however, the filter tray70of the present invention as shown inFIG. 3has the construction that the separation membranes75and the drain cloths73are attached onto the supporting plate71with thermosetting adhesive. According to such a method, the manufacturing process is simplified and the productivity increases.

In the present invention, the passage through which the slurry is supplied and then is discharged is constituted by two water passage ports79formed on the filter tray70, so it is needless to form separate passage outside of the filter tray70. Accordingly, the size of the system can be reduced as much as 120% or more in the aspect of area, so the processing efficiency per unit area increases.

INDUSTRIAL APPLICABILITY

According to the present invention, the pollutant material adhered to the separation membrane can be removed effectively since various types of vortex water flow are generated over wide range. Therefore, the efficiency of the filtering apparatus in processing the polluted water increases, and the energy loss of the filtering apparatus is reduced. Furthermore, sufficient vortex water flow can be generated with low energy even for the fluid of different characteristics such as density or viscosity.