WO1997041943A1

WO1997041943A1 - Apparatus and method for purifying exhaust gas

Info

Publication number: WO1997041943A1
Application number: PCT/KR1996/000088
Authority: WO
Inventors: Moon Chan Park
Original assignee: Moon Chan Park
Priority date: 1996-05-06
Filing date: 1996-06-11
Publication date: 1997-11-13
Also published as: AU6139196A

Abstract

A method and apparatus for purifying exhaust gas with an inner housing (17) including a processing gas chamber (1) arranged for introducing the exhausted gas and a fresh gas chamber (2) being arranged for discharging the fresh gas and a circumferential wall having an opening for exhausting impurities between the processing gas chamber (1) and the fresh gas chamber (2); a rotation shaft (15); a filter (4) for filtering the exhaust gas passing from the processing gas chamber (1) through the filter to the fresh gas chamber (2), the filter having a first circumference end fixed to the rotations shaft (15) and a second circumference end circumferentially guided in the opening of the inner housing; an outer housing (1a, 2a) disposed so as to enclose the inner housing (17), the inner housing and the outer housing being radially spaced from each other so as to define a capture chamber (3).

Description

TITLE OF THE INVENTION

APPARATUS AND METHOD FOR PURIFYING EXHAUST GAS

FIELD OF THE INVENTION

The present invention relates to an apparatus for eliminating impurities including minute particulates, dust, mist or noxious gases from exhaust gas (including polluted air) which is discharged at pollution areas such as a subway station and an industrial plant, or from exhaust gas discharged from a furnace, a boiler, or an internal combustion engine (especially diesel engine) .

BACKGROUND OF THE INVENTION

In general, it is not easy to completely eliminate impurities from gas or air discharged in an environmentally polluted area, during a manufacturing process, or from an internal combustion engine because the gas or air has heat and/or viscosity. Due to such difficulty, there has been a limit in selecting a gas purifier and a dirt-collector . According to the conventional method, the cyclone dirt-collector utilizing centrifugal force does not have high efficiency, and the scrubber, cleansing type dirt-collector, has shortcomings that it can not process relatively great quantity of gas and it costs too much expense for its operation. Further, the electric dirt-collecting method using static electric charges also has disadvantages that its operational efficiency is not constant according to the operated time and its operational expense is too costly also.

SUMMARY OF THE INVENTION

The present invention has been made to overcome the above described problems of the prior arts, and accordingly it is an object of the present invention to provide an apparatus and a method for purifying exhaust gas (including polluted air), in which the gas is filtered by a direct filtering method instead of an indirect filtering method, and in which the filtering of the exhaust gas is performed simultaneously with the regeneration of the filter such as brushes, woven or non- woven cloth, so that the gas can be filtered with high efficiency maintained durably. According to the present invention to achieve the above object, the exhaust gas or processing gas passes through brushes (including other kinds of filters) rotating at high speed. Then, the gas and the impurities are separated from each other by the filtering operation of the rotating brushes, and fresh gas after passing the brushes is discharged while the filtered impurities on the brushes are discharged radially by the centrifugal force due to the rotation of the brushes. It is preferred that cleansing solution is sprayed onto the processing gas or the rotating brushes according to the dryness of the processing gas, and at the same time the processing gas passes therethrough, thus the impurities are more efficiently captured and filtered, the brushes are more efficiently cleansed, and fluid films are formed at portions for guiding the high-speed rotation of the brushes. Further, high voltage may be applied to the processing gas so as to charge the impurities with static charges while voltage of an opposite polarity is applied to the filter, so that the filtering efficiency may be further elevated. In addition, the number of the processing gas chambers, the fresh gas chambers, and the filters therebetween, may be changed by changing the number of sections defining the processing gas chambers and the fresh gas chambers, when the quantity of the processing gas is changeable.

BRIEF DESCRIPTION OF THE DRAWINGS The above object, and other features and advantages of the present invention will become more apparent by describing in detail preferred embodiments thereof with reference to the attached drawings, in which:

FIG. IA is a longitudinal section of an exhaust gas purifying apparatus in its axial direction according to an embodiment of the present invention;

FIG. IB is a sectional view taken along the line A-A in FIG. IA;

FIG. 2A is a longitudinal section of an exhaust gas purifying apparatus in its axial direction different from FIG. IA according to an embodiment of the present invention; FIG 2B is a sectional view taken along the line B-B

FIG. 3 is a front elevation of the apparatus in FIG. IA in the horizontally installed state; FIG. 4 is a circuit diagram for showing the operation of the apparatus of the present invention and associated systems;

FIG. 5 is a partial section of an exhaust gas purifying apparatus according to other embodiment of the present invention;

FIG. 6 is a partial section of an exhaust gas purifying apparatus according to another embodiment of the present invention;

FIG. 7 is a side elevation of an exhaust gas purifying apparatus of the present invention in which the apparatus is erected as a standing type;

FIG. 8 is a partial section of the apparatus for showing the installed construction of porous and thin brush supporting plates as the first example; FIG. 9 is a partial section of the apparatus for showing an exemplary construction for spraying the cleansing solution simultaneously with cooling the inner bearings;

FIG. 10 is a partial section of the apparatus for showing the installed construction of porous and thin brush supporting plates as the second example,

FIG. 11A is a partial section of the apparatus for showing the installed construction of porous and thin brush supporting plates as the third example;

FIG. 11B is a sectional view taken along the line 11-

11 in FIG. 11A;

FIG. 12A is a partial section of the apparatus for showing the installed construction of porous and thin brush supporting plates as the fourth example; and

FIG. 12B is a sectional view taken along the line 12-

12 in FIG. 12A;

FIG. 13 is a partial section of the apparatus for showing the installed construction of porous and thin brush supporting plates as the fifth example.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Several preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Referring to FlGs. IA and IB and FIGs. 2A and 2B, a plurality of gas supply tubes 7 penetrates through the divided outer housings la and 2a and the divided inner housings 17 of a processing gas chamber l. A distributor 8 is connected to the gas supply tubes 7 and interconnects them to each other. A plurality of gas supply tubes 9 penetrates through the divided outer housings la and 2a and the divided inner housings 17 of a fresh gas chamber 2. A distributor 10 is connected to the gas supply tubes 9 and interconnects them to each other.

A rotation shaft 15 extends through the centers of an upper cover 11 and a lower cover 12, and inner bearings 16 are disposed around the rotation shaft 15 with regular intervals so as to prevent the rotation shaft 15 from vibrating and being deformed by heat. The inner bearings 16 adopts a water-cooling method. That is, cooling water circulates through cooling water introducing ports 21 formed in a center of separators 5 which are means for fixing the rotation shaft 15.

Brushes 4 respectively having a disc shape and functioning as a filter are fixed to the rotation shaft 15 with being spaced out with regular intervals apart. The divided inner housings 17 have flanges extending outward and are disposed at either sides of the brushes 4, the circumferences of the brushes 4 being inserted and guided between the flanges, and thereby the processing gas chamber 1, the fresh gas chamber 2, and a capture chamber 3 are insulated from each other. Nozzles 13, spraying means, are provided with the processing gas chamber 1 and supported by the outer housing la, the divided inner housings 17 and the inner bearings 16, spraying the cleansing solution toward the processing gas and the brushes 4. The separators 5 and 6 for holding the inner bearings 16 and maintaining spaces for the capture chamber 3 are disposed between each of the divided outer housings la and 2a and each of the divided inner housings 17. Referring to FIG. 3, drain tubes 20 connected to a drain tank 26 are provided under the divided outer housings la and 2a, so that polluted cleansing solution may be drained to the drain tank 26. Retainers 18 and outer bearings 19 embracing opposite ends of the rotation shaft 15 extending through the upper cover 11 and the lower cover 12 are disposed out of the upper cover 11 and the lower cover 12. The rotation shaft 15 is connected to and driven by a driving motor 24 or an engine through a driving pulley 14. The divided outer housings la and 2a are assembled with each other by the outer housing assembling bolts 23, and the number of the processing gas chamber 1, the fresh gas chamber 2, and the brushes 4 corresponding to such a divided construction may be selectively determined according to the quantity of the processed gas.

When the inner bearings 16 are needed to be cooled, the apparatus of the present invention may further include a cooling water supply tube 34 and a cooling water exhaust tube 35 connected to a cleansing solution transferring tube 33 as shown in FIG. 4 and a plurality of nozzles 13' formed with desired angles and shapes at a bearing housing surrounding each of the inner bearings 16, the nozzles 13' being interconnected to a cooling water path 16' defined between the bearing housing and each of the inner bearings 16.

With reference to FIG. 4, the apparatus has a drain tank 26 for collecting the polluted cleansing solution drained through the drain tubes 20 and elements for filtering the polluted cleansing solution and for cooling, recirculating, and reusing the polluted hot cleansing solution, such as the cleansing solution transferring tube 33, a discharge tube 36, a cleansing solution filter 27, a cleansing solution pump 28, a cleansing solution transferring tube 29.

A supplementary solution tank 30, a supplementary solution introducing tube 31, a supplementary solution transferring tube 32, and a discharge tube 36 may be connected to the drain tank 26 as depicted by the broken line when the apparatus is a fixed-type, while a cleansing solution introducing port 32' or a supplementary solution introducing port and a discharge port 36' may be arranged at the drain tank 26 when it is a movable type such as an automobile.

While the above description with reference to the attached drawings is based on the construction divided by sections, the present invention must not be restrictively understood by the above description, and thereby the inner and the outer housings may be integrally formed with each other and accordingly other construction may be changed in the scope of the present invention. Hereinbelow, the operation and the function of the embodiments of the present invention having the above construction will be described with reference to the accompanying drawings.

As shown in FIGs. 1 through 4, processing gas introduced through the distributor 8 and the gas supply tubes 7 into the processing gas chamber 1 flows through the brushes 4 into the fresh gas chamber 2 of low pressure by an exhaust fan 25, and cleansing solution such as water, oil, chemical substance, etc. is sprayed through the nozzles 13 of the processing gas chamber 1 into the central portions of the brushes 4 rotating at high speed. When the apparatus is driven as a dry-type, cleansing air instead of the cleansing solution may be made to gust. The cleansing solution in the following description includes the cleansing air .

The sprayed cleansing solution 13b from the nozzles 13 is dispersed radially by centrifugal force, thereby cleansing the brushes 4 and forming a fluid film between each of the brushes 4 and the divided inner housings 17 , so as to assure the smooth and high-speed operation of the brushes and prevent the processing gas from being bypassed through a gap for the fluid film. The processing gas flowing from the processing gas chamber 1 to the fresh gas chamber 2 is filtered directly by the brushes 4 and at the same time mixed with the sprayed cleansing solution 13b. In this case, minute particles and mist entrained in the gas are absorbed or captured by the sprayed cleansing solution 13b, and accordingly the processing gas is filtered more efficiently.

The filtered alien substance or impurities including the minute particles and mist passes through gap between two adjacent flanges of the divided inner housings 17 to the capture chamber 3 by centrifugal force. At this time, the gas is filtered and the brushes 4 are regenerated simultaneously. In the meantime, the gas in the processing gas chamber l is prevented from passing through the gap between the flanges of the divided inner housings 17 by the film of the cleansing solution. Instead, the gas passes only through and filtered by the brushes 4, thereby lubricating the brushes 4 and increasing the filtering efficiency.

The fresh gas having passed the brushes 4 flows through the gas supply tubes 9 and the distributor 10, and is introduced through a fresh gas introducing port 10a and a exhaust duct 10b to the exhaust fan 25 and then discharged out.

Meanwhile, the cleansing solution arrived at the capture chamber 3 is retrieved into the drain tank 26 through the drain tubes 20 under the divided outer housings la and 2a and then filtered by the cleansing solution filter 27 through the cleansing solution transferring tube 33. Thereafter, the cleansing solution flows through the cleansing solution pump 28 and is cooled by the cleansing solution transferring tube 29, and continues to flow through the cleansing solution transferring tube 33, cleansing solution introducing ports 13a, and then is sprayed to the brushes 4 by the pressure of the cleansing solution pump 28. Further, a part of the cleansing solution having passed the cleansing solution transferring tube 29 cools the inner bearings 16 through the cooling water supply tube 34 interconnected to the cleansing solution transferring tube 33 and the cooling water introducing ports 21, and then flows through the cooling water exhaust ports 22 and the cooling water exhaust tube 35 to the drain tank 26. To prevent excessive pollution of the cleansing solution, a predetermined amount of the cleansing solution is discharged out through the discharge tube 36. The quantity of the cleansing solution is reduced because of evaporation and dispersion and because a part of the cleansing solution is discharged through the discharge tube 36. Therefore, the cleansing solution is supplemented into the dram tank 26 by means of the supplementary solution tank 30 and the supplementary solution introducing tube 31. When the apparatus is a movable type which is usually adopted by an automobile, the apparatus does not include the supplementary solution introducing tube 31 and the discharge tube 36. Instead, the cleansing solution may be drained through the discharge port 36' after a predetermined time and supplied, changed, or supplemented through the cleansing solution introducing port 32' .

Referring to FIG. 5, a high-voltage electrode 37 is disposed in the middle of the distributor 8 and a low- voltage electrode 40 is disposed at the outer housing. In this case, the processing gas introduced m the distributor 8 is charged with static electric charges by the high-voltage electrode 37 and low-voltage electric current having a polarity different to that of the high- voltage electrode 37 is transmitted through the low- voltage electrode 40, and then charged particles are further captured by the dirt-collected and polarized brushes 4, so that the filtering efficiency is further increased.

Referring to FIG. 6, the nozzles 13 are arranged also in the fresh gas chamber 2, so that the cleansing solution may be sprayed also to the brushes 4 at the fresh gas chamber side with respect to the gas having passed the brushes 4 without being mixed with the cleansing solution. Through this spray of the cleansing solution, dirts are secondarily sucked or captured from the gas, and the filtering efficiency is further increased.

While the brushes 4 rotate vertically according to the embodiment shown in FIG. 3, the brushes 4 rotate horizontally according to the embodiment shown in FIG. 7 in which the exhaust gas purifying apparatus is erected as a standing-type and dram tubes 20-1 connected to the drain tank 26 are disposed under the lower cover 12. According to the latter embodiment in which the brushes 4 rotates horizontally, the sagging of the brushes 4 in the rotational direction of the brushes 4 which may be found often in the exhatist gas puiifymg apparatus of FIG. 3 when it is stopped to be driven is prevented, so that the brushes 4 may be relatively large and the quantity of the processing gas may be increased.

Moreover, two porous and thin brush supporting plates 4' shown as the first example in FIG. 8, are disposed at opposite sides of the filter for supporting the brushes 4, each of which has a shape of a porous and thin circular disc plate and a width between which radially decreases, thus the filter is prevented from sagging and can rotate smoothly while maintaining uniform density of the filter. Referring to FIG. 9, the inner bearings 16 support the rotation shaft 15 and the separators 5 for fixing the inner housings extend from the exterior of the divided outer housings la and 2a into the divided inner housings 17. The inner bearings 16 is held by a bearing housing supported by the separators 5. Further, the separators 5 may be hollow shaft so as to cool the inner bearings 16 when the exhaust gas is too hot. In this case, the cleansing solution is introduced through the interior of the hollow shaft and cools the inner bearings 16 through the cooling water path 16', and then are sprayed through the plural nozzles 13' formed through the bearing housing and interconnected to the cooling water path 16'. Therefore, the cooling function and the spraying function are performed without separate spraying means.

Two porous and thin brush supporting plates 44 are shown as the second example in FIG. 10. The two filter supporting plates 44 have an inner filter supporting portion 44' and an outer filter supporting portion 47 for supporting the brushes 4 circumferentially at a radially inner end and a radially outer end of the brushes 4, so that a processing gas space 50 is formed between said inner and outer filter supporting portions 44' and 47 to pass the processing or exhaust gas through the brushes 4 almost all over the surface of the brushes 4 and the rotation of the two filter supporting plates 44 and 44 and the brushes 4 is guided by the adjoining two flanges 17' of the divided inner housings 17 at a lubricating film gap 50 by means of the cleansing solution between each flange 17' and the outer filter supporting portion 47 each filter supporting plate 44.

The two porous and thin brush supporting plates 44 are shown as the third example in FIGs. 11A and UB. Circumference projections 17" and 48 are formed in each of the outer filter supporting portion 47 of the filter supporting plates 44 and the flanges 17 ' of the divided inner housing 17 so as to keep a lubricating film of the cleansing solution strong in the lubricating film gap 50.

The two porous and thin brush supporting plates 44 are shown as the fourth example in FIGs. 12A and 12B. A plurality of connecting flanges 17a and 49 are formed radially outwardly in the flange 17' of the divided inner housings 17 and the filter supporting plates 44 for fixing each respectively, said plurality of connecting flanges 17a and 49 being separated from each other in the circumferential direction to provide the opening for the exhausted impurities. In FIGs. 12A and 12B, a blade flange 49' is also formed in each of plurality of connecting flanges 49 so as to keep the lubricating film airtight and to prevent the exhaust gas and the cleansing solution from introducing into the fresh gas chamber through the lubricating film gap 50.

The two porous and thin brush supporting plates 44 are shown as the fifth example in FIG. 13. Lubrication bushes 51 and 52 are disposed in each of the flanges 17' of the divided inner housings 17 and the outer filter supporting portions 47 of the filter supporting plates 44 at the lubricating film gap 50, guiding the rotation of the brushes 4 and the filter supporting plates 44.

As apparent from the construction and the operation described above according to the embodiments of the present invention, the apparatus of the present invention has advantages that it can filter the gas with high efficiency and maintain the high efficiency durably because it filters the gas by a direct filtering method and because it adopts a successive operation method in which the filtering of the exhaust gas is performed simultaneously with the regeneration of the filter such as brush, woven or non-woven cloth.

While the present invention has been particularly shown and described with reference to the particular embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be effected therein without departing from the spirit and scope of the invention as defined by the appended claims. For example, the inner and the outer housings and the upper and the lower covers may be formed integrally with each other, and spacers may be interposed between the flanges of the divided inner housings 17 and the flanges be assembled by assembling bolts as is the same in case of the divided outer housings la and 2a for fixing the divided inner housings 17. The rotation shaft 15 may be divided to several sections, each of the sections being rotatably fixed. Furthermore, for filtering polluted air, the distributor 8 can be replaced by a first filter for preliminarily cleaning the polluted air.

Claims

WHAT IS CLAIMED IS:

1. A method for purifying exhaust gas including polluted air, said method comprising the steps of:

(1) introducing the exhaust gas into a processing gas chamber ;

(2) filtering the exhaust gas off impurities by passing the introduced exhaust gas in an axial direction through a filter rotating at high speed; and

(3) collecting and eliminating the impurities filtered through the filter by a centrifugal force of the filter in a radial direction.

2. A method as claimed in claim 1, said introducing step 1 further comprising the step of charging the impurities entrained in the exhaust gas with static electric charges by means of a high-voltage electrode so as to increase capability of capturing the impurities through the filter in said filtering step 2.

3. A method as claimed in claim 1 or claim 2, wherein cleansing solution is sprayed into the processing gas chamber so as to make the most impurities be captured by spray of the cleansing solution in said introducing step 1, capturers in which the spray of the cleansing solution captures and the most impurities are adhered together are filtered together with the rest impurities in said filtering step 2, and the filtered capturers are collected and eliminated in said collecting and eliminating step 3.

4. A method as claimed in claim 1, said method further comprising the steps of separating the impurities and the cleansing solution from each other through a drain tank and a separation filter from the capturers collected and eliminated in said collecting and eliminating step 3, and then recirculating the separated cleansing solution into the processing gas chamber .

5. An apparatus for purifying exhaust gas including polluted air, said apparatus comprising: an inner housing including at least a processing gas chamber and at least a fresh gas chamber defined in the inner housing and a circumferential wall enclosing the processing gas chamber and the fresh gas chamber, the processing gas chamber being arranged for introducing the exhaust gas, the fresh gas chamber being arranged for discharging the fresh gas, the circumferential wall having an opening for exhausting impurities between the processing gas chamber and the fresh gas chamber; a rotation shaft rotatably disposed at a center of the inner housing; at least a filter of a circular disc shape for filtering the exhaust gas passing from the processing gas chamber through the filter to the fresh gas chamber off impurities, the filter having a first circumference end fixed to the rotation shaft and a second circumference end circumferentially guided in the opening of the inner housing, the filter rotating along with the rotation shaft, the rotation of the filter making the impurities of the filter be exhausted out of the inner housing through the opening by a centrifugal force of the rotating filter; and an outer housing disposed so as to enclose the inner housing, the inner housing and the outer housing being radially spaced from each other so as to define a capture chamber between the inner housing and the outer housing, the exhaust impurities being collected into the capture chamber and then eliminated.

6. An apparatus as claimed in claim 5, wherein the outer housing comprises a plurality of divided outer housings corresponding to the number of the processing gas chambers and the fresh gas chambers and means for fixing the divided outer housings, and the inner housing comprises a plurality of divided inner housings corresponding to the number of the processing gas chambers and the fresh gas chambers and means for fixing the divided inner housings, each of the divided inner housings having a flange extending outward from its filter side, the divided outer housings and the divided inner housings being able to increase and decrease according to the capacity of the exhaust gas, the filter being guided in a gap defined between each two flanges adjoining each other, the gap functioning as the opening for exhausting the impurities .

7. An apparatus as claimed in claim 6, the apparatus further comprising means for spraying cleansing solution into at least one of the processing gas chamber and the filter, so that the impurities are captured and filtered more easily, that the filter is cleansed while the impurities are exhausted along with the cleansing solution, and that a fluid film is formed in the gap in which the filter is guided, the spraying means being disposed in the inner housing.

8. An apparatus as claimed in claim 7 , the apparatus further comprising a drain tank interconnected to the capture chamber, means for filtering only the cleansing solution, a pump connected to a circulation line to circulate the cleansing solution, and means for cooling the cleansing solution when the exhaust gas is hot, the drain tank having an impurity-exhausting port and means for introducing cleansing solution and supplementary solution, the filtering means being interconnected to the drain tank, so that the impurities mixed in the cleansing solution exhausted after being filtered are separated from the cleansing solution and then the cleansing solution is recirculated and reused.

9. An apparatus as claimed in claims 7 or claim 8, wherein the fixing means for each divided inner housing extend from exterior of each divided outer housing into each divided inner housing so as to support the rotation shaft in the divided outer housings, the fixing means supporting the rotation shaft through an inner bearing and a bearing housing interposed between a distal end of the fixing means and the rotation shaft, at least one of the fixing means at a side of the processing gas chamber being formed as a hollow shaft when the inner bearing is needed to be cooled, a path being formed in the bearing housing so as to be interconnected to an interior space of the hollow shaft, the spraying means being a plurality of nozzles extending through the bearing housing being interconnected to the path, so that the cleansing solution is introduced through the interior space of the hollow shaft into the bearing housing, cools the inner bearing and then is sprayed onto the introduced processing or exhaust gas and the filter through said plurality of nozzles of the bearing housing.

10. An apparatus as claimed in one of claims 5 through 8, the apparatus further comprising means for charging the impurities entrained in the exhaust gas introduced into the processing gas chamber of the inner housing with static electric charges, a voltage being applied to the filter, the voltage having a polarization opposite to that of the static electric charges.

11. An apparatus as claimed in one of claims 5 through 8, the apparatus further comprising two porous and thin filter supporting plates for each filter, a space between the two filter supporting plates having a radially decreasing width, each of the two filter supporting plates being disposed at opposite sides of the filter for supporting the filter, so that the filter is prevented from sagging and is capable of rotating smoothly while maintaining uniform density of the filter .

12. An apparatus as claimed in claim 11, the two filter supporting plates having an inner filter supporting portion and an outer filter supporting portion for supporting the filter circumferentially at a radially inner end and a radially outer end of the filter, so that a processing gas space being formed between said inner and outer filter supporting portions to pass the exhaust gas through the filter almost all over the surface of the filter .

13. An apparatus as claimed in claim 12, wherein the outer filter supporting portion is radially extended so that the rotation of the two filter supporting plates and the filter is guided by the adjoining two flanges of the divided inner housings, a lubricating film gap for the cleansing solution being formed between each flange and each filter supporting plate, and wherem a circumference projection is formed in each of the outer filter supporting portion of the filter supporting plates and the flanges of the divided inner housing so as to keep a lubricating film of the cleansing solution strong in the lubricating film gap.

14. An apparatus as claimed in claim 12, wherem a plurality of connecting flanges are formed radially outwardly in the flange of the divided inner housings and the filter supporting plates for fixing each respectively, said plurality of connecting flanges being separated from each other m the circumferential direction to provide the opening for the exhausted impurities.

15, An apparatus as claimed in claim 14, wherem a blade flange is formed in each of plurality of connecting flanges so as to keep the lubricating film airtight and to prevent the exhaust gas and the cleansing solution from introducing into the fresh gas chamber through the lubricating film gap.

16. An apparatus as claimed in one of claim 12 through claim 15, further comprising lubrication bushes for guiding the rotation of the filter and the filter supporting plates, said lubrication bushes being disposed in each of the flanges of the divided inner housings and the outer filter supporting portions of the filter supporting plates at the lubricating film gap.