Rotor for rotary adsorber

Abstract: A rotor and a sealing device for a rotary adsorber is disclosed. The rotor includes a rim (7), spokes (3), arc-shaped sectors (2), a calking material, and a thermal insulating seal (10,11). The spokes divides the rim into arc-shaped portions. The sectors are disposed in the rim and include a gas adsorptive element (4). The calking material is provided between each sector and one of the rim and the spoke. The thermal insulating seal covers end surfaces of the spokes and joint portions of the sectors. The sealing device includes a sealing material, a mounting plate, a connecting portion, a rod member, and a spring. The sealing material is slidably interposed between a partitioning frame of the rotary adsorber and the mounting plate. The connecting portion fixes the mounting plate to the partitioning frame. The rod member is fixed to the connecting portion. The spring is interposed between the sealing material and the connecting portion.

Description: Background of the Invention 1. Field of the Invention The present invention relates to a rotor for a rotary adsorber according to the preamble of claim 1. Such an adsorber is known from DE 28 56 184 A. The known adsorber comprises a cylindrical rim, spokes radially extending in said cylindrical rim and arc-shaped sectors disposed in said cylindrical rim and being divided by said radially extending spokes. The arc-shaped sectors include a gas adsorptive element. The rotor for a rotary adsorber known from the prior art furthermore has a sealing structure comprising sealing elements on the outer radial end of each sector and sealing elements on the inner radial end of the sectors. Those inner and outer sealing elements are connected by radial sealing elements. 2. Description of the Related Art Referring now to Figs. 7 to 10, the structure of the rotor for rotary adsorbers of the related art will be illustrated. Fig. 7 is a perspective view showing a principal portion of the rotary adsorber having a rotor rotatably held therein, Fig. 8 is a perspective view of the rotor, Fig. 9 is a cross sectional view of Fig. 8 taken along the line A-A showing a seal-mating surfaces of each arc-shaped sector and the spoke, and Fig. 10 is a partially exploded perspective view showing the entire construction of the rotor including the outer peripheral rim 507. In the rotary adsorber 500 specifically for an organic solvent provided with a conventional adsorptive element 504, adsorbed organic solvent has been removed by rotating the rotor 501 in the holding case 510 that is divided into an adsorbing zone S, a cooling zone T, and a recycling zone U, thereby temporarily defining a adsorbing zone and a recycling zone on one of the end surface of the rotor, adsorbing the organic solvent contained in gas onto the adsorbing element 504 carried by the rotor 501 when the surface of the rotor passes through the adsorbing zone S, and allowing recycling air heated to the temperature higher than 180°C-200°C, which is a boiling point of an organic solvent, to pass through the adsorptive element 504 from the end surface opposite from the end surface in the recycling zone U. Among gases containing an organic solvent, a gas generated in the manufacturing process of semi-conductor components, for example contains organic solvents such as DMSO (dimethyl sulfoxide), MEA (monoethanol amine), HMDS (hexamethilenedisilazane), and so on. These organic compounds cannot be removed sufficiently at a recycling temperature of 180 to 200°C. Therefore, such organic compounds are increasingly accumulated on the rotor, which may result in deterioration of performance or burning of the rotor. In order to remove such organic compounds, it is required to send hot air heated to about 200-350°C to the rotor 501 at the recycling zone U. The rotor 501 of honeycomb construction integrally formed into a cylindrical shape by combining a plurality of arc-shaped sectors 502 is reinforced by a plurality of metallic spokes 503 extending radially outwardly from the hub 505. The metallic spoke and the sectors 502 of honeycomb construction are joined or bonded by the use of heat resistant calking material 508 such as silicone. In addition, the metallic outer peripheral rim 507 for protecting the outer periphery of the rotor 501 and the honeycomb construction 504 itself are also bonded via a calking material 508 of silicone. As described above, the rotor 501 is rotatably mounted to the holding case 510, and the partitioning plates 511 for defining the adsorbing zone S, the recycle zone U and the cooling zone T are provided with seal (not shown) formed of silicone rubber with PTFE film applied thereon so as to slidably press against the end surface of the rotor 501 to prevent leakage or mixing of gas passing therethrough. When attempt was made to send a hot air over 200°C as described above to the rotor of such a structure for recycling, since a calking material of silicone or rubber could not resist such a high temperature, silicone or rubber was deteriorated and thus the joining performance or adhering performance between the spoke and the rotor was lowered, whereby the arc-shaped sectors constituting the rotor might fall off so that the rotor itself could not be used any more. Therefore, there was a limit on the temperature of the air to be passed through, and thus the accumulated high boiling organic solvent or polymer could not be removed sufficiently. As a consequent, the cleaning performance was lowered, or when using the solvent that can be polymerized within the rotor in which the solvent is accumulated, it could not be recycled and the polymer gave damage to pores of the adsorptive element like zeolite, thereby lowering the cleaning performance as a adsorptive element. Next, a conventional sealing device for a rotary adsorber is discussed. As discussed above, an organic solvent adsorber rotatably holds a rotor by a motor in a box-shaped casing having partitioning frame for dividing the surface of the rotor into an adsorbing zone, a recycling zone, and a cooling zone. On the other hand, the rotor includes an adsorptive element forming a plurality of fan-shaped sectors defined by a metallic cylindrical rim, which has a honeycomb construction in which a plurality of pores pass through from one end surface to the other end surface, and has the plurality of fan-shaped sectors inserted in fan-shaped spaces defined by radially extending metallic spokes. In the actual use, when a gas containing an organic solvent is blown onto the portion of one of the end surfaces of the rotor positioned at the adsorbing zone toward the other end surface thereof, an organic solvent contained in gas is adsorbed and clarified gas is discharged from the other end surface, and the rotor is rotated by a prescribed angle to move from the adsorbing zone to the recycling zone, and then the organic solvent adsorbed thereon is removed by separating and blowing off by passing a recycling air heated to the temperature higher than 180 °C to 200 °C that exceeds the boiling point of the adsorbed organic solvent from the other side to the one side to recycle the adsorptive element. In addition, the partitioning frame defining these adsorbing zone and the recycling zone on the end surface of the rotor also includes at least three radially extending partitioning plates and an annular plate or an arc shaped plate facing toward the outer peripheral portion of the end surface of the rotor and defines each fan-shaped zone by being combined with the outer end portion of the partitioning plates. These partitioning plates are further provided with sealing strips or resilient sealing blocks facing the end surface of the rotor so as to be slidable toward the end surface for preventing mutual interference of air in each fan-shaped zone. Such kind of seal has a disadvantage in that it cannot establish complete sealing performance in the cases where flatness of the end surface of the rotor is not satisfactory as the first problem, and where the end surface of the rotor during rotation does not form a plane exactly perpendicular with respect to the axis of rotation as the second problem. Especially in the rotary gas adsorber of the type described above, there is a problem in that the rotor develops deflection during rotation so that the end surface of the rotor does not form a perpendicular plane at an exact right angle with respect to the axis of rotation. In addition, these sealing strips or resilient sealing blocks require heat resistance, wear resistance and chemical stability. Summary of the Invention Accordingly, it is an object of the present invention to provide a rotor for a rotary adsorber provided with a thermal insulating seal that can well resist a high temperature exceeding 200°C. According to the present invention, the first object described above can be achieved by a rotary adsorber as defined in claim 1. This arrangement prevents a heated hot recycling air from being blown directly onto the joint portion between the sectors and the spoke, and thus prevents increase in temperature of calking material, thereby preventing lowering of sealing property or adhering force due to deterioration of calking material. Simultaneously, a hot air is blown onto the adsorptive element other than the portion of the thermal insulating seal, so that a boiling organic solvent or polymer adhered to the adsorptive element is separated and blown off, thereby preventing lowering of adsorbing performance when the adsorptive element itself is reused. According to a preferred embodiment of the rotor for rotary adsorbers of the present invention, the thermal insulating seal is mounted via a mounting plate welded on the end surface of the spoke, i.e. the surface of the spoke extending parallel to the front surface of the cylindrical rim and perpendicular to the peripheric surface defined by said rim. In this arrangement, complex molding process for mounting the thermal insulating seal plate directly on the spoke may be avoided, and replacement thereof can easily be performed. According to another preferred embodiment of the rotor for rotary adsorbers of the present invention, the thermal insulating seal is secured to the mounting plate by a screw. This arrangement significantly facilitates replacement of the thermal insulating seal. According to still another preferred embodiment as defined in claim 5 a hot air is prevented from being blown directly to a calking material between the metallic rim and the outer peripheral surface of the arc-shaped sector, thereby preventing deterioration of a calking material. According to further preferred embodiment of the rotor for rotary adsorbers of the present invention, the thermal insulating seal is a silicon nitride plate. In this arrangement preferable, thermal insulating effect is obtained and simultaneously durability of the plate of incombustible material itself is ensured, thereby preventing deterioration of its performance even after many hours of service and having excellent thermal insulating effect. According to still further preferred embodiment of the rotor for rotary adsorbers according to the present invention, the thermal insulating seal is a laminated body in which a metal plate is overlaid on a sheet of expanded black lead. In this arrangement, since a sheet of black lead has high heat resistance, and in addition, a metal plate is overlaid thereon, a sheet of expanded black lead, which is fragile in itself, is protected to ensure high toughness and durability, whereby an excellent thermal insulating effect is maintained for a long time. According to an additional preferred embodiment of the rotor for rotary adsorbers of the present the invention, a heat insulating material is interposed between the mounting plate and the thermal insulating seal. This arrangement alleviates heat transferred to the joined surfaces via the spoke that is exposed to a hot air to some extent by providing a heat insulating material, and a calking material is further protected from a high temperature. According to another preferred embodiment of the rotor for rotary adsorber of the present invention, the heat insulating material is a calcium silicate plate. This arrangement ensures an excellent heat insulating effect between the heated plate of incombustible material and the mounting plate mounted to the spoke, thereby ensuring protection of a calking material from heat. In the construction of the rotor for rotary adsorber according to the present invention described above, it is preferred to employ silicone resin or fluorine-contained rubber having adhesive property as a calking material. Further preferred embodiments are set out in claims 2 and 7. In the following, the invention will be described in further detail with respect to embodiments of the invention in combination with the drawings. Brief Description of the Drawings Fig. 1 is a perspective view of a rotor for rotary adsorbers. Fig. 2 is a cross sectional view of Fig. 1 taken along the line X-X showing the implementation of the rotor for rotary adsorbers according to the present invention. Fig. 3 is a drawing as Fig. 2 showing another embodiment of the rotor for rotary adsorbers according to the present invention. Fig. 4 is a drawing as Fig. 3 showing another embodiment of the rotor for rotary adsorbers according to the present invention. Fig. 5 is a partially exploded perspective view showing the entire construction of the rotor for rotary adsorbers according to the present invention including the outer peripheral rim including a thermal insulating seal. Fig. 6 is a cross sectional view of Fig. 1 taken along the line Y-Y showing the rotor for rotary adsorbers according to the present invention including the outer peripheral rim including the thermal insulating seal. Detailed Description of the Preferred Embodiments Referring now to the drawings, several embodiments of the rotor for rotary adsorber according to the present invention will be described. Fig. 1 is a perspective view of the rotor itself for rotary adsorber according to the present invention; Fig. 2 is a partial cross sectional view of Fig. 1 taken along the line X-X illustrating an embodiment of the rotor for the rotary adsorber according to the present invention; Fig. 3 is a same drawing as Fig. 2 showing another embodiment of the rotor for rotary adsorber according to the present invention; Fig. 4 is a same drawing as Fig. 3 showing another embodiment of the rotor for rotary adsorber according to the present invention; Fig. 5 is a partially exploded perspective view showing the entire construction of a rotor for rotary adsorber according to the present invention including an outer peripheral rim provided with a thermal insulating seal; and Fig. 6 is a cross sectional view of Fig. 1 taken along the line Y-Y of a rotor for the rotary adsorber according to the present invention including outer peripheral rim provided with a thermal insulating seal. In Figs. 1 to 6, the thermal insulating seals 10 and 11 of the rotor 1 for rotary adsorbers according to the present invention is provided with eight arc-shaped sectors 2 each including a gas adsorptive element 4 of ceramic fiber paper of honeycomb construction having a number of through holes in the cylindrical rim 7 partitioned into arc-shaped portions in cross section by spokes 3 radially extending therein. The contact surface between adjacent two sectors 2 out of the sectors and the combination of the spoke 3 and rim 7 are integrally formed by silicone joined by a preferable calking material 8. Generally, the rotor including the gas adsorptive element 4 of honeycomb construction has a construction having a number of small through holes extending across both front surfaces, and especially when it is used for the process of cleaning a volatile organic compound containing gas generated in a semi-conductor manufacturing process, a harmful volatile organic compound contained in the gas is adsorbed on the surface of the small through holes when the gas is passed through the small through holes. Incombustible materials that can be used for the gas adsorptive element 4 of the rotor in the present invention are required to have heat resistance, heat-insulating property, wear resistance, and solvent resistant property. In other words, when the temperature of the rotor increases, the portion between the spokes, which is supporting the rotor, and the honeycomb construction is deformed by high heat, and thus there is no other choice but to use incombustible materials in order to prevent such deformation. The reason why heat resistance is required is because the material has to resist air at a high temperature of 200-350°C, and the reason why heat insulating property is required is because the material have to protect the rotor from the air at a high temperature of 200-350°C. Wear resistance is required because friction is generated between itself and the sealing material described later, and solvent resistant property is required because the rotor has a property of adsorbing organic solvent. As an incombustible material that satisfies these properties, materials formed of inorganic material such as silicone nitride, graphite, ceramic paper, or felt are employable. Fig. 1 and Fig. 5 show a state in which the thermal insulating seals 10, 11 formed of plates of incombustible material for the rotor 1 of rotary adsorber are mounted on one front surface of the spoke 3 - a surface which extends perpendicular to the peripheric surface defined by the cylindrical rim 7 and in parallel with the front surface thereof ― and the outer peripheral rim 7 of this rotor in parallel therewith, and according to an embodiment of the present invention, these thermal insulating seals are plates of incombustible material; silicone nitride. Especially when such a rotor for rotary adsorber is used in the semi-conductor manufacturing plant, it is inevitable to use a material being highly resistant to an organic solvent because it is always effected chemically by the organic compound containing gas generated during its manufacturing process. Therefore, as one of specific materials, silicone nitride is preferable material. The construction of the present invention will be clearly understood from the description regarding the embodiment shown in Figs. 2 to 6. Fig. 2 shows an embodiment of the rotor 1 for rotary adsorber according to the present invention showing the relation between the spoke 3 of the rotor 1 and silicone nitride plate 10 as a thermal insulating seal. The metallic spoke 3 is joined or adhered to the two adjacent sectors 2a, 2b out of six arc-shaped sectors constituting the rotor 1 with a calking material 8. The spoke 3 is provided with a metallic mounting plate 9 welded thereon at a right angle, in other words, in parallel with the front surface of the rotor 1 (a surface extending perpendicular to the peripheric surface thereof) , and the silicone nitride plate 10 is fixed to the mounting plate 9 by a screw 13. The silicone nitride plate 10 is wider than the mounting plate 9 exposed on the end surface of the rotor in width, and is as wide as it can be fitted into the radially extending rectangular recess 14 in cross section, which is formed at the joint portion between two adjacent sectors 2a, 2b with the spoke 3 interposed therebetween. Therefore, a preferable effect is obtained such that the thermal insulating seal does not project from the end surface of the rotor. As shown in Fig. 3, instead of the silicone nitride plate, it is proposed to use an expanded black lead sheet 15 to prevent deterioration of a calking material between the spoke 3 and the adjacent sectors by an expanded black lead sheet 15. However, it is also possible to employ the construction that a metallic plate 16 is overlaid on the expanded black lead sheet 15. The laminated construction may be applied to the thermal insulating seal 11 to be provided on the radially end surface of the rim 7. As shown in Fig. 4, by providing heat insulating material 17 of, for example, calcium silicate plate between the mounting plate 9 of the spoke 3 and the silicone nitride plate 10, heat insulating performance can be further improved. Fig. 5 and Fig. 6 are cross sectional drawings of the end surface of the rotor, showing a state in which a silicone nitride plate 11 is mounted at the peripheral edge portion of the metallic outer peripheral rim 7 that appears on the end surface of the arc-shaped sector 2. In this arrangement, even when heated air is introduced into the rotor from the above of the drawings, the joint portion is protected from heat by protecting the calking material 8 by a silicone nitride plate 11. In Fig. 6, though it is preferred to provide a metallic angle member 12 under the silicone nitride plate 11 so as to be embedded in the outer peripheral edge portion of the sector, it is also possible to provide the silicone nitrides plate 11 alone. As is described thus far, since the rotor for rotary adsorber according to the present invention is constructed in such a manner that arc-shaped sectors formed of a gas adsorptive element of the honeycomb construction having a number of small through holes are arranged in the cylindrical rim partitioned into arc-shaped portions in cross section by the spoke radially extending therein, a calking material is interposed between these respective sectors and the combination of the spoke and rim, and a thermal insulating seal in the shape of a plate formed of incombustible material for covering a front surface of the spoke and the joint surface of the two arc-shaped sectors that come into contact with both sides of the end surface is mounted in parallel with the end surface, even when the high boiling organic solvent in excess of 200°C or a solvent that can be polymerized both of which were not able to be processed in the related art is attached to the adsorptive element, a hot air higher than 200 °C can be flown into the rotor continuously all the time at the recycle zone without causing deterioration of the calking material such as silicone or the like. The rotor for rotary adsorbers according to the present invention enables removal of an organic solvent attached onto the adsorptive element, which has been impossible to be cleaned in the related art, and enables the adsorptive element in the rotor to be used continuously and repetitively without lowering the performance thereof and the mechanical strength of the rotor itself. Therefore, quick and smooth operation of exhaust gas processing can be performed continuously, and lowering of efficiency of exhaust gas processing can be prevented, thereby contributing to elongate the life of the rotor significantly.

Claims: A rotor (1) for a rotary adsorber comprising: a cylindrical rim (7) defining a peripheric surface, spokes (3) radially extending in said cylindrical rim (7) and dividing said cylindrical rim (7) into arc-shaped portions in cross section, arc-shaped sectors (2) disposed in the arc-shaped portions of said cylindrical rim (7), each of said sectors (2) including a gas adsorptive element (4), characterized by a calking material (8) provided between each sector (2) and one of said cylindrical rim (7) and said spoke (3), and a thermal insulating seal (10) fixed to a mounting plate (9) perpendicular to said spoke (3) all along its longitudinal direction and extending perpendicular to the peripheric surface of said cylindrical rim (7), wherein said thermal insulating seal (10) is fixed on said mounting plate (9) on a side opposite to said spoke (3) and is wider than the width of the mounting plate (9), so that a portion of both sectors (2) separated by said spoke (3) is covered by said thermal insulating seal (10) fixed on said mounting plate (9), and wherein said thermal insulating seal (10) is made of an incombustible material. The rotor for a rotary adsorber according to claim 1, wherein the gas adsorptive element (4) of said sectors (2a, 2b) includes a honeycomb construction having a plurality of small through holes. The rotor for a rotary adsorber according to claim 1 or 2, wherein said mounting plate (9) is welded to the end surface of said spoke (3). The rotor for a rotary adsorber according to claim 3, wherein said thermal insulating seal (10) is secured on said mounting plate (9) by a screw (13). The rotor for a rotary adsorber according to any of the preceding claims, composing a further thermal insulating seal (11) mounted at a peripheral portion of said cylindrical rim (7) and covering a joint portion between said sectors (2) and an inner surface of said cylindrical rim (7). The rotor for a rotary adsorber according to any of the preceding claims, wherein said thermal insulating seal (10) is silicone nitride. The rotor for a rotary adsorber according to any of the preceding claims, wherein said thermal insulating seal (10) is expanded black lead. The rotor for a rotary adsorber according to any of the preceding claims, wherein said thermal insulating seal (10) is a laminated body including an expanded black lead sheet (15) and a metal plate (16) overlaid on the expanded black lead sheet (15). The rotor for a rotary adsorber according to any of the preceding claims, wherein a heat insulating material (17) is interposed between said mounting plate (9) and said thermal insulating seal (10). The rotor for a rotary adsorber according to claim 9, wherein said heat insulating material (17) is made of calcium silicate.

Inventors: ASAHINA SHUSAKU, KUROSAWA MASAJI, TANAKA YASUHIRO, YAMASHITA KATSUHIRO, ASAHINA, SHUSAKU, KUROSAWA, MASAJI, TANAKA, YASUHIRO, YAMASHITA, KATSUHIRO
Applicants: NICHIAS CORP, NICHIAS CORPORATION
Application year: 2001
Main classification: B01D53
IPC codes: F24F3, B01D53