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  • 专利说明
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    • 专利摘要:
    A method of drying a honeycomb molded body using microwaves is disclosed. The method can reduce the difference in drying rate within the honeycombed molded bodies during the drying process and can dry the dimpled molded bodies without deformation of the cells. The method comprises placing the honeycomb molded body in a drying oven with the cell axis in the vertical direction and exposing the honeycomb molded body to microwaves at a frequency of 300-30,000MHz. The difference in moisture content in the vertical direction of the honeycomb molded body 1 is maintained at 0.3% per mm or less during microwave exposure.
    公开号:BE1018418A3
    申请号:E2005/0403
    申请日:2005-08-24
    公开日:2010-11-09
    发明作者:Tatsuya Terazawa；Naoyuki Shimada；Yasuharu Kuno；Takayuki Sakurai
    申请人:Ngk Insulators Ltd；
    IPC主号:
    专利说明:

    DESCRIPTION
    METHOD FOR MICROWAVE DRYING OF MOLDED ALUMINUM BODIES
    The present invention relates to a method of drying a honeycomb molded body using microwaves.
    The honeycomb structural bodies are widely used as a catalyst support and various filters and have recently attracted attention as a diesel particulate filter (DPF) for trapping loose particles from a diesel engine.
    In many cases, such a honeycomb structural body contains a ceramic material as the main component. This type of honeycomb structural body is usually made by producing a kneaded substance (clay) by adding water and various additives to a ceramic raw material, extruding the kneaded substance (the clay) into a molded honeycomb-shaped body (a body). molded honeycomb) and drying and sintering the honeycomb molded body.
    A known method of drying the honeycomb mold is a dielectric drying process utilizing high frequency energy generated by passing a current between electrodes installed in the upper and lower portions of the honeycomb molded body. A hot air drying process in which a hot wind produced by a gas burner or the like is used is also known. In recent years, a drying method using microwaves is used instead or in combination with these drying techniques because of the advantages of a high drying speed and the like (for example, Japanese demand made available to the public for 2002-283329).
    Traditionally, dimpled moldings are dried by a microwave drying process by providing a drying oven with uniform distribution of the electric field and placing the molded molded cells in the oven. The method used to ensure a uniform distribution of the electric field is a method of adjusting the shape and location of the antenna which diffuses microwaves, a method using a stirring fan, etc.
    However, these conventional microwave drying methods have not been able to uniformly dry the complete dimpled moldings due to slow drying rates at the top and bottom ends and perimeter of the dimpled moldings. Since a molded hollow body shrinks due to the evaporation of the water, the difference in drying speed (difference in the amount of water) within the molded body causes deformation of the cells in the hollowed structural body. The thickness of the ribs (partitions dividing the alveoli) structural honeycomb cells has been reduced in recent years. The smaller the thickness of the rib, the easier the cell is deformed. For this reason, the importance of ensuring a uniform speed of drying has increased.
    The effects of heat dissipation of dimpled molded bodies, heat release, latent heat transpiration, etc. during the drying process are considered to cause the difference in drying speed. In an effort to ensure a uniform drying rate of the microwave molded moldings, a method of reducing heat dissipation by raising the temperature in the drying oven to about 80.degree. C., for example by introducing steam or steam. hot air in the drying oven, a method of reducing the effect of heat dissipation by increasing the flow of microwaves etc. have been proposed. Although deformation can be suppressed to some extent by using these methods, a sufficient reduction of the drying rate to provide a satisfactory difference in the results is difficult.
    The present invention has been made in view of this situation and is intended to provide a method of drying a honeycomb molded body using microwaves, by which the drying of the molded molded bodies can be produced without causing deformation of the cells and sufficiently reducing the difference in drying velocity within the dimpled molded bodies during the drying process.
    More particularly, the present invention provides a drying method of a microwave molded molded body which comprises placing the honeycomb molded body in a drying oven with the cell axis in the vertical direction and exposing the molded honeycomb body to microwaves at a frequency of 300 - 30,000 MHz while maintaining the difference in water content in the vertical direction of the honeycomb molded body at 0.3% per mm or less (a first microwave drying process).
    The present invention further provides a method of drying a microwave molded molded body which comprises placing the honeycomb molded body in a drying oven with the cell axis in a vertical direction and exposing the molded body microwaves at a frequency of 300-30,000 MHz, wherein the honeycomb molded body is placed inside a cylindrical screen such that the distance between the outer circumference of the honeycomb molded body and the surface internal screen is in the range of 5 mm to Ά of the microwave length (a second microwave drying process).
    The present invention further discloses a method of drying a molded honeycombed cell using microwaves which comprises placing the honeycomb molded body in a drying oven with the axis of cells in a vertical direction, moving the molded body in a predetermined direction and exposing the molded body to microwaves at a frequency of 300-30,000 MHz during displacement, in which a pair of screen plates are installed on either side of the path of movement of the molded body of such in such a way that the honeycombed molded body is placed between them, the distance between the perimeter of the honeycomb molded body and the screen being of the order of 5 mm at Va of the wavelength of the microwaves (a third micro-drying method -ondes).
    The present invention further discloses a method of drying a molded cell using microwaves which comprises locating the molded molded body in an oven with the axis of the cells in a vertical direction, moving the honeycomb molded body in a predetermined direction, and exposing the honeycomb molded body to wave lengths at a frequency of 300-30,000 MHz during displacement, wherein a lead paddle is provided for placing a plurality of dimpled moldings in a direction orthogonal to the feed direction, said die plates being screen are installed on the pallet of advance, the distance between the honeycomb molded body and the screen being of the order of 5 mm at Va of the wavelength of the microwaves (a fourth microwave drying process) .
    According to the present invention, the difference in the drying rate inside the honeycomb moldings is sufficiently reduced during the drying process so that the honeycomb moldings are dried substantially without deformation of the cells.
    Figure 1 is a schematic diagram illustrating an embodiment of the first microwave drying method of the present invention.
    Figure 2 is a schematic diagram illustrating an alternative embodiment of the first microwave drying method of the present invention.
    Figure 3 is a schematic diagram illustrating the part of the cell to judge whether the cells are deformed or not.
    Figure 4 is a schematic diagram illustrating alveolenormale.
    Figure 5 is a schematic diagram illustrating an estimated cell.
    Figure 6 is a perspective view illustrating an embodiment of a second microwave drying process.
    Figure 7 is a top view illustrating an embodiment of a second microwave drying process.
    Figure 8 is a top view illustrating an embodiment of a third microwave drying process.
    Figure 9 is a top view illustrating another embodiment of the third microwave drying process.
    Figure 10 is a top view illustrating an embodiment of a fourth microwave drying process.
    Figure 11 is a schematic diagram illustrating the points for measuring residual moisture in dimpled moldings in the reference examples and examples.
    Figure 12 is a graph illustrating the results obtained in Reference Example 1.
    Figure 13 is a graph illustrating the results obtained in Reference Example 2.
    Figure 14 is a graph illustrating the results obtained in Reference Example 3.
    Figure 15 is a graph illustrating the results obtained in Reference Example 4.
    Figure 16 is a graph illustrating the results obtained in Example 1.
    Figure 17 is a graph illustrating the results obtained in Reference Example 5.
    Figure 18 is a graph illustrating the results obtained in Example 2.
    Figure 19 is a graph illustrating the results obtained in Example 3.
    Figure 20 is a graph illustrating the results obtained in Reference Example 6.
    Figure 21 is a graph illustrating the results obtained in Example 4.
    The first microwave drying method of the present invention comprises placing the honeycomb molded body in a drying oven with the cell axis in the vertical direction and exposing the honeycombed body to microwaves at a frequency of 300. - 30,000 MHz while maintaining the difference in the water content in the vertical direction of the honeycomb molded body (direction of the cell axis) to 0.3% per mm or less.
    As a result of several experiments, the inventors of the present invention have found that if the honeycomb molded body is exposed to microwaves while maintaining the water content in the vertical direction of the honeycomb molded body, the difference in the drying speed at the The interior of the dimpled molded bodies can be sufficiently reduced during the drying process and it is possible to dry the molded molded bodies substantially without deformation of the cells.
    This ideal distribution of water content in the vertical directional molded body during the drying process can be attained by maintaining the microwaves incident density (W / cm 2) from the vertical direction of the honeycomb molded body to be greater than the incident density (W / cm2) from the horizontal direction and, at the same time, regulating the microwave output density (kW / kg) to be the threshold value or more of the density in which the cells of the honeycomb molded body are no longer deformed.
    As previously mentioned, in conventional microwave drying processes, the drying rate at the upper and lower ends and the perimeter of the dimpled molded bodies tends to be slowed relative to other parts of the dimpled moldings. More specifically, in the direction of vertical of the honeycomb molded body, the drying speed is lower in the upper and lower ends to the central portion while in the radial direction, the perimeter dryer more slowly than the inner portion of the molded hollow body.
    The inventors of the present invention have investigated the reasons for the different drying rates at different points within the molded honeycomb body and found that the heat dissipation in the drying process significantly affected the difference in drying speed (difference in the value of the residual content). in water) in the vertical direction of the honeycomb molded body. The types of microwave energy released on a honeycomb molded body are generally classified as energy consumed by heat dissipation and energy consumed by latent heat. Among these, since the energy consumed by heat dissipation is constant (a fixed value), the energy consumed by heat dissipation decreases as the output density of the microwaves increases. As a result, the energy rate consumed by the latent heat increases and the effect of the heat dissipation on the difference in drying speed decreases. Deformation of the honeycomb molded body is avoided in this manner.
    Therefore, it is preferable to set the microwave output density (kW / kg) to a value greater than the threshold value at which the cells of the honeycomb molded body are no longer deformed. The thermal efficiency of an ordinary microwave drying oven (energy effectively used for drying / leaving the microwave) is about 0.5. The threshold value of the microwave output density at which the cells of the honeycomb molded body are no longer deformed in this microwave drying oven is about 3 kW / kg. Therefore, if the microwave output density is set to 3 kW / kg or more, preferably 3.6 kW / kg (equivalent to 120% of the threshold value) or higher, taking into account the variation in heat and As the incident density is suitably controlled as described later in this specification, it is possible to maintain the optimum optimum difference in water content in the vertical direction of the molded body during the drying process.
    To judge whether the cells of the dimple molded body are deformed or not, sections at a distance of 30 mm or less from below and above the honeycomb molded body 1 (see Figure 3) are evaluated. In cessions, one side of a normal opening of the cells 15 is assumed to be 1 in length (see Figure 4). The cell is judged "undistorted" if a round object with a diameter of 0.9 can be inserted into the cell. If the round object can not be inserted into the cell, the cell is considered "deformed" (see Figure 5).
    In addition, it has been found that, if the incident density of the microwaves in vertical direction (direction of the end face) and the incident density in the horizontal direction (direction of the side face) of the honeycomb molded bodies are adjusted in such a way that If the first is above the last, the difference in drying speed in the vertical direction of the honeycomb molded body can also be reduced and the difference in drying speed in the radial direction can be suppressed. A specific method, as illustrated in Figure 1, is to inhibit the incidence of microwaves from a horizontal direction, for example by providing a microwave reflector such as an aluminum foil 3 around the face side of a molded hollow body 1 or by placing a reflector (metal plate) surrounding the facelateral of the honeycomb molded body. Another method comprises installing a waveguide tube 7 both above and below the honeycombed molded body 1 which is placed on a table 5 in the drying oven to positively expose the honeycomb molded body 1 from the above and below as shown in Figure 2.
    In the present invention, the incident density of microwaves A from the vertical direction and the incident density of microwaves B from the horizontal direction of the honeycomb molded body preferably satisfy the equation of A / (A + B). > 0.7. A high effect of regulating deformation of the cells can be achieved if the incident microwave density A from the vertical direction and the incident density of the B microwaves from the horizontal direction of the honeycomb molded body preferably satisfy this equation.
    The second invention comprises a method of drying a microwave molded molded body which comprises placing the molded honeycomb body in a drying oven with the cell axis in the vertical direction and exposing the honeycomb molded body to microwells. waves at a frequency of 300 - 30,000 MHz, in which the molded body is placed inside a cylindrical screen so that the distance between the outer circumference of the honeycomb molded body and the internal circumference of the screen is of the order 5 mm Ά of the wavelength of the microwaves.
    If the honeycomb molded body is placed in a cylindrical screen, the outer circumference of the honeycomb molded body is covered by the screen and the incident density of the microwaves from the horizontal direction of the honeycomb molded body is limited by the screen. Therefore, the incident density of the microwaves from the vertical direction of the honeycomb mold becomes larger than the incident density from the horizontal direction.
    As already described in the description of the first microwave drying method, if the incident microwave density in the vertical direction is greater than the incident density in the horizontal direction of the honeycomb molded body, the dry speed difference in the vertical direction of the Molded molded body can not only be reduced but the difference in drying speed in the radial direction can also be suppressed. Therefore, the difference in drying speed inside the honeycomb molded body can be sufficiently reduced, ensuring the drying of the honeycomb molded body without deformation of the cells.
    If the outer circumference of the honeycomb molded body is covered by a screen in the case where two or more molded moldings are placed next to each other and simultaneously dried in a drying oven, mutual interference between the adjacent honeycomb moldings is inhibited, thereby preventing differences in drying conditions between the honeycomb moldings. In addition, since a vapour produced from the honeycomb mold itself can maintain the space around the honeycomb moldings at a moderate temperature and humidity, it is possible to dry the products without producing wrinkles and molds. recesses on the outer circumference. In Japanese Patent Application Laid-Open No. 2002-283329, etc., describing a technology of the state of the art, the interior of the drying oven is set to an atmosphere with a high humidity rate of 70%. or more fully to achieve the same effect. In the present invention, however, the effects described above can be achieved without maintaining such an atmosphere.
    Figures 6 and 7 are respectively a perspective view and a top view of an embodiment of the second microwave drying process. In this example, a metal cylinder is used as a cylindrical screen 17 in which the honeycomb molded body 1 is placed.When the inner cross-section of the drywall molded body has a circumferential configuration different from a cylinder, a tubular body having the same internal configuration of crosswise cut that the inner cross section of the honeycomb molded body is preferably used as a screen. The screen can be composed of a material other than a metal insofar as such a material can effectively prevent the propagation (or reflect) microwaves.
    In the second microwave drying method, the distance (Di) between the outer circumference of the honeycomb molded body 1 and the internal surface of the screen 17 is adjusted to 5 mm or more but 1 or less than the wavelength of the microwave. For example, in the case of microwaves at a frequency of 2.45 GHz, commonly used in the microwave drying of a honeycomb molded body since these microwaves have a wavelength of 120 mm, the distance (D) between the outer circumference of the honeycombed molded body 1 and the inner surface of the screen 17 is 5 - 30 mm.If the distance (Di) is less than 5 mm, the drops of water produced on the inner surface of the screen can adhere to the outer circumference of the honeycomb molded body, leading to variations in the drying rate of the outer circumference.If the resistance (Di) is greater than λλ of the wavelength of the microwaves, it is difficult to sufficiently prevent the incident density of microwaves from the horizontal direction of the honeycomb molded body.
    The length or height (L) of the screen 17 is preferably located between the length of the honeycomb molded body 1 to be dried plus V 2 of the microwave wave length and the length of the honeycomb molded body 1 minus
    Vz of the wavelength of the microwaves (specifically, when the center of the screen 17 in the vertical direction and the center of the molded body 1 in the vertical direction are the same, the maximum length of the screen 17 is such that the ends the top and bottom of the screen 17 are provided with a gap equal to Va of the wavelength of the microwaves above the surface of the upper end and below the surface of the lower end of the molded molded body 1, the minimum length of the screen 17 being such that the upper and lower ends of the honeycomb molded body 1 are provided with a gap equal to Va of the wavelength of the microwaves above the surface of the upper end and below the surface of the lower end of the screen 17) and, especially, equivalent to the length of the honeycomb molded body 1. When the length (L) of the screen 17 is less than the length of the body 1, the upper ends and / or the lower end of the honeycomb molded body 1exceed from the upper end and / or the lower end of the screen 17. In such a case, if the length (L) of the Screen 17 is not within the margin specified above, the projected length is too large to achieve a sufficient screen effect. When the length (L) of the screen 17 is greater than the length of the honeycomb molded body 1, the upper end and / or the lower end of the screen 17 protrude from the upper end and / or the lower end. In such a case, if the length (L) of the screen 17 exceeds the range specified above, not only the incident density of the microwaves from the horizontal direction of the honeycomb molded body 1 but also the incident density of the moldings. Microwaves from the vertical direction may be limited.
    The third microwave drying method of the present invention includes placing the honeycomb molded body in an oven with vertical axis orientation, causing the honeycomb mold to move in a predetermined direction and exposing the honeycomb mold to microwaves at a frequency of 300-30,000 MHz in which a pair of screen plates are installed on either side of the path of movement of the molded molded body such that the molded molded body is placed between them, the distance between the perimeter of the honeycomb molded body and the screen being of the order of 5 mm at V * of the wavelength of the microwaves.
    If the screen plates are installed on either side of the path of displacement of the honeycomb molded body with the hollow molded body placed therebetween, the incident density of the microwaves from the horizontal direction of the honeycomb molded body is limited by the Therefore, the incident density of the microwaves from the vertical direction of the honeycomb molded body exceeds the incident density from the horizontal direction.
    As indicated above, if the incident density of the microwaves in the vertical direction exceeds the incident density in the horizontal direction of the honeycomb molded body, not only the difference in drying speed in the vertical direction of the honeycomb molded body can be reduced but the difference in speed of Drying in the radial direction can also be suppressed. Consequently, the difference in drying speed inside the honeycomb molded body can be sufficiently reduced, ensuring the drying of the honeycomb molded body without deformation of the cells.
    Figure 8 is a top view illustrating an embodiment of a third microwave drying process. The third microwave drying method is based on the principle that the dimpled moldings are dried in a continuous drying oven while being transported one after the other by a transport mechanism such as a belt conveyor or a belt conveyor. rolls. Each hollow molded body 1 is successively transported in the direction of the arrow illustrated in FIG.
    FIG. The screen plates 18 are installed on either side of the displacement lavoie of the honeycombed molded body 1 so that the honeycomb molded body is placed between them. A metal plate may equally well be used as a screen 18. However, materials other than metal may also be used as long as the material can effectively prevent the propagation (reflection) of the microwaves. In addition, it is possible to install two or more parallel conveyor paths for the dimpled molded bodies 1 in the same drying oven and to install screen plates 1 on each side of the transport path, as illustrated. in Figure 9.
    In the third microwave drying method, the distance (D2) between the honeycomb molded body 1 and the screen plate 18 is adjusted to 5 mm or more, but Va or less than the wavelength of the microwaves . For example, in the case of microwaves at a frequency of 2.45 GHz, commonly used in the microwave drying of a molded-in molded body, since these microwaves have a length of 120 mm, the distance (D 2) between the outer circumference of the honeycomb molded body 1 and the inner surface of the screen 18 is 5 - 30 mm. If the distance (D2) is less than 5 mm, the drops of water produced on the surface of the screen may adhere to the outer circumference of the molded body, resulting in variations in the rate of drying of the outer circumference. If the distance (D2) is greater than Va of the wavelength of the microwaves, it is difficult to sufficiently prevent the microwave incident density from the horizontal direction of the honeycomb molded body.
    The fourth method of microwave drying comprises placing the molded molded body in a furnace with the axis of the cells in a vertical direction, moving the honeycomb molded body in a predetermined direction and exposing the honeycomb molded body to microwaves. frequency of 300-300.000 MHz in displacement, in which a pallet of advance is provided for placing a plurality of dimpled molded bodies in the direction orthogonal to the direction of transport, said screen plates are installed on the pallet in advance, the distance between the hollow molded body and the screen being of the order of 5 mm Va, of the wavelength of the microwaves.
    If the screen plates are installed on the transport pallet on which two or more honeycomb moldings are placed side by side, the incidental microwave frequency from the horizontal direction of the honeycomb molded body is limited by the screen plates. As a result, the incident density of the microwaves from the vertical direction of the molded molded body becomes larger than the incident density from the horizontal direction.
    As previously reported, if the incident density of the microwaves in the vertical direction exceeds the incident density in the horizontal direction of the honeycomb molded body, not only the difference in drying speed in the vertical direction of the honeycomb molded body can be reduced but the difference in speed of drying in the horizontal direction can also be deleted. Therefore, the difference in drying rate within the honeycomb molded body can be sufficiently reduced, ensuring the drying of the molded hollow body, with virtually no deformation of the cells.
    Figure 10 is a top view illustrating an embodiment of the fourth microwave drying process. The fourth microwave drying method is based on the principle that the blister moldings are dried in a continuous drying oven while being transported one after the other by a transport mechanism such as a belt conveyor or a belt conveyor. rolls. Two molded molded bodies 1 or more are disposed on a transport plate 21 in the directionorthogonal to the direction of movement (the direction of the arrow in the figure) to be transported successively. The advance pallet 21 is a plate made of a porous ceramic or other material, installed on a transport mechanism in such a way that its elongitudinal side is orthogonal to the direction of advance and advanced with two molded molded bodies 1 or more placed on this one. A metal plate may suitably be used as a screen 19 to be installed on the feed pallets 21. However, any material other than the metal may be used as well, since the material may effectively prevent the propagation (reflect) of the microwaves.
    In the fourth microwave drying process, the distance (D3) between the honeycomb molded body 1 and the screen plate 19 is adjusted to 5 mm or more but% or less of the wavelength of the microwaves. For example, in the case of microwaves at a frequency of 2.45 GHz, which are commonly used in the microwave drying of a hollow molded body, since these microwaves have a wavelength of 120 mm, the distance ( D3) between the outer circumference of the molded hollow body 1 and the inner surface of the screen 19 and 5 - 30 mm. If the resistance (D3) is less than 5 mm, the drops of water produced on the surface of the screen may adhere to the outer circumference of the honeycombed molded body, leading to variations in the drying rate of the outer circumference. If the distance (D3) exceeds Va of the microwave wave length, it is difficult to sufficiently prevent microwave incident density from the horizontal direction of the honeycomb molded body.
    In the fourth microwave drying method, as illustrated in the example of Figure 10, in addition to the screen 19 installed on the pallet 21, if a pair of plate-shaped screens 20 are installed from and on the other side of the moving path along which the honeycombed molded bodies 1 placed on the feed pallet 21 are transported in such a way that the honeycomb moldings are placed between them, the incident density of the microwaves from The horizontal direction of the honeycomb molded body 1 may be otherwise limited by a screen 20 and the difference in drying speed within the honeycomb molded body 1 may be further reduced.
    In the present invention, the frequency of the microwaves used to expose the honeycomb molded body is 300-30,000 MHz and preferably 900 to 5,000 MHz. If the microwave frequency is below 300 MHz, a large volume is required for the furnace for a long wavelength of about 1 m or more. On the other hand, a frequency of microwaves above 30,000 MHz can only be applied to small dimpled molded bodies because such microwaves can penetrate only the honeycomb molded body to a limited extent.
    The honeycomb molded body to be dried in the present invention is prepared from a kneaded substance which is prepared by the addition of water and various additives to ceramic and other materials used as raw materials. The kneaded substance is then molded into the shape of the honeycomb molded body. The alveolate shape in the sense of the present document refers to a configuration of an object having a number of through-holes (cells) each separated by partitions (ribs) and penetrating in the axial direction. Although there is no specific limitation on the quality of the material, the density of the cells, the thickness of the ribs, the shape of the cells, etc. Of the molded body to which the present invention is applied, the present invention is particularly effective for a honeycomb molded body having a rib thickness which is easily deformed.
    EXAMPLES
    The present invention is described below in more detail by examples. However, the present invention is not limited to the following examples.
    Reference Example 1
    Talc, kaolin, alumina, binder, water etc. were mixed and mixed. The kneaded material obtained was extruded from an extruder into a honeycomb molded body 120mm in diameter, 200mm in length, wall thickness about 100pm and having about 300 cells per inch. square (about46 / cm2). This molded body was placed vertically (so that the cell axis is in the vertical direction) in a batch microwave oven (heating efficiency: 0.5) and dried by exposure to microwaves. a frequency of 2.45 GHz for 300 seconds at an output density of 1 kW. In this example, the contribution of microwave incident density from the vertical direction to the incident density from the horizontal direction of the honeycomb molded body is assumed to be about 1: 1.
    After drying, the residual water content was measured for the gauge 11 and the core 13 of the honeycomb molded body 1 shown in FIG. 11, each time from a height of 0 (below) to 200 (above). The results are illustrated in Figure 12. As can be seen in Figure 12, the honeycomb molded product can be dried more slowly in the perimeter than in the core using a microwave drying procedure. In the vertical direction, the upper and lower ends (respectively about 30 mm above and below) are dried more slowly than in the center.
    Reference Example 2
    Talc, kaolin, alumina, binder, water etc. were mixed and kneaded. The kneaded material obtained was extruded from an extruder to provide a honeycomb molded body 120mm in diameter, 220mm in length, wall thickness about 100pm and having about 300 cells per inch. square (about46 / cm2). This molded body was placed vertically (so that the cell axis is in the vertical direction) in a batch microwave oven (heating efficiency: 0.5) and dried by exposure to microwaves. a frequency of 2.45 GHz for 600 seconds at an output density of 0.5 kW / kg. In this example, the ratio of microwave incident density from the vertical direction to the incident density from the horizontal honeycomb molded body direction is assumed to be about 1: 1. After drying, the residual water content was measured for the perimeter 11 and the molded honeycomb core 1 illustrated in FIG. 11, each time from a height of 160 (below) to 220 (above).
    Reference Example 3
    A molded body prepared in the same manner as in Example 2 was placed vertically (so that the axis of the cells is in the vertical direction) in a batch microwave oven (heating efficiency: 0). 5) and dried by microwave exposure at a frequency of 2.45 GHz for 60 seconds at an output density of 5 kW / kg. In this example, the contribution of microwave incident density from the vertical direction to the incident density from the horizontal direction of the honeycomb molded body is assumed to be about 1: 1. After drying, the residual water content was measured in the same manner as in Reference Example 2. The results are illustrated in Figure 14.
    Figures 13 and 14 show that the difference in residual water content in the vertical direction, i.e., the difference in the vertical drying rate, is lower than Example 3 with an exit density of microwaves of 5 kW / kg higher than Reference Example 2 with microwave power density lower than 0.5 kW / kg. The reason supposed is that, the higher the exit density of the microwaves, the higher the proportion of energy consumed by the latent heat compared to the energy consumed by the heat dissipation is high, the effect of the difference of the drying speed heat dissipation has since decreased. However, the deformation of the cells could not be sufficiently regulated, even in Reference Example 3.
    Reference Example 4
    Talc, kaolin, alumina, binder, water etc. were mixed and mixed. The kneaded material obtained was extruded from an extruder into a honeycomb molded body having a diameter of 120 mm, a length of 170 mm, a wall thickness of about 100 μm and having about 300 cells per inch. square (about46 / cm2). This molded body, one side of which was surrounded by aluminum foil, was placed vertically (so that the axis of the honeycomb was in a vertical direction) in a batch microwave oven (heating efficiency: 0.5). and dried by exposure to microwaves at a frequency of 2.45 GHz for 900 seconds at an output density of 0.5 kW / kg. In this example, the ratio of the incident microwave density from the vertical direction to the incident intensity from the horizontal direction of the molded body is assumed to be about 1: 0. After drying, the residual water content was measured for the perimeter 11 and the core 13 of the molded hollow body 1 shown in Fig. 11, each time from a height of 110 (below) to 170 (above).
    Example 1
    The molded body prepared in the same manner as in Reference Example 4 was placed vertically (so that the axis of the cells is in the vertical direction) in a batch microwave oven (heating efficiency: 0). 5) and dried by microwave exposure at a frequency of 2.45 GHz for 90sec at an output density of 5 kW / kg. In this example, the contribution of microwave incident density from the vertical direction to the incident density from the horizontal direction of the honeycomb molded body is assumed to be about 1: 0. After drying, the residual water content was measured in the same manner as in Reference Example 4. The results are illustrated in Figure 16.
    In both Reference Example 4 and Example 1, an aluminum foil was wrapped around the side face of the molded bodies to reflect microwaves from the horizontal direction so that the incident density from the vertical direction to the dimple molded bodies may be greater than the incident density from the horizontal direction. In Reference Example 4 in which the microwave output density was low (0.5 kW / kg) while the difference in the residual water content between the perimeter and the core was minimal, the difference in water content was large in the vertical direction of the honeycomb molded body to prevent the deformation of the cells sufficiently. On the other hand, in the example in which the microwave output density was large (5 kW / kg), the difference in residual water content in the perimeter and core was not only minimal but the difference in water content in the direction The vertical molded honeycomb body was also miniscule enough to dry the entire molded body at a uniformly uniform speed with virtually no deformation of the cells.
    Reference Example 5
    Talc, kaolin, alumina, binder, water etc. were mixed and mixed. The kneaded material obtained was extruded from an extruder into a honeycomb molded body 120mm in diameter, 200mm in length, wall thickness about 100pm and having about 300 cells per inch. square (about46 / cm2). This molded body was placed vertically (so that the cell axis is in the vertical direction) in a batch microwave oven (heating efficiency: 0.5) and dried by exposure to microwaves. a frequency of 2.45 GHz for 60 seconds at an output density of 5 kW / kg. In this example, the contribution of microwave incident density from the vertical direction to the incident density from the horizontal direction of the honeycomb molded body is assumed to be about 1: 1. After drying, the residual water content was measured for the perimeter 11 and the molded honeycomb core 13 illustrated in FIG. 11, each time from a height of 0 (below) to 200 (above).
    Example 2
    The hollow molded body produced in the same manner as in Reference Example 5 was placed vertically (so that the axis of the cells is in the vertical direction) in a cylindrical screen composed of a metal having an internal diameter of 140 mm and a length of 200 mm. The cylindrical screen was placed in a batch microwave oven (heating efficiency: 0.5). The distance between the gauge of the honeycomb molded body and the inner surface of the screen was 10 mm. The molded body was then dried by exposure of microwaves at a frequency of 2.45 GHz for 60 seconds at an output density of 5 kW. In this example, the incident density A from the vertical direction and the incident density B from the horizontal direction of the honeycomb molded body corresponded to the equation A / (A + B)> 0.7. After drying, the residual water content was measured in the same manner as in Reference Example 5. The results are illustrated in Figure 18.
    Example 3
    A honeycomb molded body was microwaved in the same manner as in Example 2 except that the length of the cylindrical metal screen was 180 mm. After drying, the residual water content was measured in the same manner as in Reference Example 5. The results are shown in Figure 19.
    Reference Example 6
    A hollow molded body was microwaved in the same manner as in Example 2 except that the inner diameter of the cylindrical metal screen was 270 mm and the distance between the perimeter of the honeycomb molded body and the inner surface of the screen was 75 mm. After drying, the residual water content was measured in the same manner as in Reference Example 2. The results are illustrated in FIG. 20.
    Example 4
    Three hollow molded bodies produced in the same manner as in Reference Example 5 were placed with the axis of the vertical end cells on a path of travel in a continuous-cycle microwave drying oven (heating efficiency: 0.degree. 5) .The distance between the adjacent molded bodies was 20 mm. A pair of metal screen plates (height: 220 mm, length: 500 mm, thickness: 1 mm) were installed on both sides of the track in such a way that the hollow molded bodies were placed between them. The distance between the screen plates and the honeycombed molded bodies was 20 mm. The molded body was then dried by exposure to microwaves at a frequency of 2.45 GHz for 60 seconds at an output density of 5 kW / kg. In this example, the incident density A from the vertical direction and the incident density B from the horizontal direction of the honeycomb molded body corresponded to the equation of A / (A + B)> 0.7. After drying, the residual water content was measured in the same manner as in Reference Example 5. The results are illustrated in Figure 21.
    Figures 17 and 18 show that in Example 2 in which the incident microwave density from the horizontal direction is limited by the cylindrical metal screen plates such that the incident microwave density from the As the vertical direction of the molded honeycomb can become larger than the incident density from the horizontal direction, the difference in the residual water content in the vertical direction as well as the difference in the residual water content in the perimeter and the core were minimal, indicating that the difference in the rate of drying inside the molded bodies was small. Figures 18 and 19 show that in Example 3, in which the length of the screen is shorter than the length of the honeycomb molded body, unlike Example 2 in which the length of the screen is the same as the length of the honeycombed molded body, the difference in the residual water content in theperipherium and the core is slightly greater in the upper part from which the honeycomb molded body exceeds the upper end of the screen. Figures 18 and 20 show that the difference in the residual water content in the vertical direction was greater in Reference Example 6 in which the distance between the perimeter of the honeycomb molded body and the inner surface of the screen was more than Va dela microwaves wavelength (120 mm) than in Example 2 in which the distance is more than 5 mm but less than Va of the wavelength of the microwaves. In addition, Figure 21 indicates that the metal screens installed on either side of the moving path in a continuous-cycle microwave drying oven can also effectively limit the microwave incident density from the horizontal direction, which reduces both the difference in water content in the vertical direction and the difference in residual water content in the perimeter and the core, ensuring a uniform drying life in each part of the molded body.
    The process is suitably applied to the drying of molded hollow bodies used as a catalyst support and a diesel particulate filter for the purification of exhaust gases.
    权利要求:
    Claims (7)
    [1]
    A method of drying a microwave molded molded body which comprises: placing the honeycomb molded body in a drying oven with the cell axis in the vertical direction and exposing the honeycomb molded body to microwells; waves at a frequency of 300-30,000 MHz while maintaining the water content difference in the vertical direction of the honeycomb molded body at 0.3% per mm or less.
    [2]
    The method of claim 1, wherein the incident density of the microwaves from the vertical direction of the honeycomb is greater than the incident microwave density from the horizontal direction and the microwave output density is adjusted. to reach the threshold value or more of the output density at which the cells of the honeycomb molded body are no longer deformed.
    [3]
    The method of claim 2, wherein the incident density A from the vertical direction and the incident density B from the horizontal direction of the honeycomb molded body satisfy the equation A / (A + B)> 0.7.
    [4]
    A method of drying a microwave molded molded body which comprises: placing the honeycomb molded body in a drying oven with the cell axis in the vertical direction and exposing the honeycomb molded body to microwells; 300-30,000 MHz frequency waves in which the honeycombed shaped body is placed inside a cylindrical screen such that the distance between the outer circumference of the honeycomb molded body and the inner surface of the screen is of the order from 5 mm to 1/4 of the wavelength of the microwaves.
    [5]
    5. The method of claim 4 wherein the length of the screen is between the length of the honeycomb molded body plus V2 of the microwave wavelength and the length of the VFE cavity molded body of the wavelength of the microwaves. -ondes.
    [6]
    6. A method of drying a microwave molded molded body which comprises: placing the honeycomb molded body in a drying oven with the axis of the cells in the vertical direction, moving the honeycomb molded body in a predetermined direction, and exposing the molded molded body to microwaves at a frequency of 300-30,000 MHz in motion, wherein a pair of screen plates are installed at each other from the moving path of the honeycomb molded body so that the molded molded body is placed between them, the distance between the perimeter of the honeycomb molded body and the screen being of the order of 5mm to Va of the wavelength of the microwaves.
    [7]
    7. A method of drying a microwave molded molded body which comprises: placing the molded molded body in a drying oven with the axis of the cells in the vertical direction, moving the molded molded body in a predetermined direction, and exposing the molded molded body to microwaves at a 300-30,000 MHz traveling frequency in which an advance pallet is provided for placing a plurality of dimpled moldings in a longitudinal direction at the advance direction, said screen plates are installed on the pallet of advance, the distance between the molded molded body and the screen being about 5 mm to Va of the wavelength of microwaves.
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    同族专利:
    公开号 | 公开日
    JP4745722B2|2011-08-10|
    JP2006088685A|2006-04-06|
    US7197839B2|2007-04-03|
    US20060042116A1|2006-03-02|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US5388345A|1993-11-04|1995-02-14|Corning Incorporated|Dielectric drying of metal structures|
    US20020112364A1|2001-02-02|2002-08-22|Ngk Insulators, Ltd.|Method of drying honeycomb structural bodies|
    US20030057205A1|2001-09-26|2003-03-27|Tomio Minobe|Microwave continuous heating apparatus|
    US20030102602A1|2001-12-04|2003-06-05|Yasunao Miura|Method and apparatus for manufacturing honeycomb molding using a high humidity atmosphere|
    WO2003082540A1|2002-03-28|2003-10-09|Ngk Insulators, Ltd.|Method of drying honeycomb formed body|
    EP1491307A1|2002-03-28|2004-12-29|Ngk Insulators, Ltd.|Method of drying honeycomb formed body|
    US20040104514A1|2002-11-19|2004-06-03|Denso Corporation|Method and apparatus for drying ceramic molded articles|
    US4570045A|1984-03-08|1986-02-11|Jeppson Morris R|Conveyorized microwave heating chamber with dielectric wall structure|
    JPH061150B2|1986-12-27|1994-01-05|日本碍子株式会社|Dielectric drying method of honeycomb structure|
    JP4386518B2|1999-12-14|2009-12-16|イビデン株式会社|Method for drying ceramic molded body and jig for drying ceramic molded body|
    US6932932B2|2001-01-16|2005-08-23|Denso Corporation|Method of fabricating honeycomb body|
    JP2002283329A|2001-01-16|2002-10-03|Denso Corp|Manufacturing method of honeycomb formed body and drying equipment thereof|
    JP4131103B2|2001-01-16|2008-08-13|株式会社デンソー|Method for manufacturing honeycomb molded body and drying apparatus|
    JP4103984B2|2001-01-16|2008-06-18|株式会社デンソー|Method for manufacturing honeycomb molded body and drying apparatus|
    JP4069613B2|2001-11-09|2008-04-02|株式会社デンソー|Manufacturing method and drying apparatus for ceramic honeycomb structure|
    JP4172986B2|2002-10-10|2008-10-29|日本碍子株式会社|Honeycomb structure, manufacturing method thereof, and exhaust gas purification system using the honeycomb structure|
    WO2005023503A1|2003-09-02|2005-03-17|Ngk Insulators, Ltd.|Method and apparatus for drying honeycomb formed article|
    CN100441991C|2003-09-04|2008-12-10|日本碍子株式会社|Method of drying honeycomb molded body|
    JP4527963B2|2003-11-04|2010-08-18|日本碍子株式会社|Microwave drying method|WO2005023503A1|2003-09-02|2005-03-17|Ngk Insulators, Ltd.|Method and apparatus for drying honeycomb formed article|
    WO2007108076A1|2006-03-17|2007-09-27|Ibiden Co., Ltd.|Drying device, method of drying ceramic molding, and method of producing honeycomb structure body|
    US7596885B2|2006-07-28|2009-10-06|Corning Incorporated|Microwave drying of ceramic structures|
    JP5368970B2|2007-03-28|2013-12-18|日本碍子株式会社|Method and apparatus for drying honeycomb molded body|
    JP5352576B2|2007-03-30|2013-11-27|コーニングインコーポレイテッド|Method and applicator for selective electromagnetic drying of ceramic forming mixtures|
    US8729436B2|2008-05-30|2014-05-20|Corning Incorporated|Drying process and apparatus for ceramic greenware|
    US9239188B2|2008-05-30|2016-01-19|Corning Incorporated|System and method for drying of ceramic greenware|
    EP2539656B1|2010-02-25|2015-07-29|Corning Incorporated|Tray assemblies and methods for manufacturing ceramic articles|
    JP5388916B2|2010-03-17|2014-01-15|日本碍子株式会社|Method for drying honeycomb formed body|
    MX2013010162A|2011-03-07|2013-09-26|Sumitomo Chemical Co|Drying method and drying device for green honeycomb molded body.|
    US9038284B2|2011-11-29|2015-05-26|Corning Incorporated|Systems and methods for efficient microwave drying of extruded honeycomb structures|
    JP5832312B2|2012-01-16|2015-12-16|三菱重工業株式会社|Method for drying honeycomb structure|
    JP5832337B2|2012-02-24|2015-12-16|三菱重工業株式会社|Method for drying honeycomb structure|
    JP5848162B2|2012-02-29|2016-01-27|三菱重工業株式会社|Method for drying honeycomb structure|
    US9188387B2|2012-05-29|2015-11-17|Corning Incorporated|Microwave drying of ceramic honeycomb logs using a customizable cover|
    US8782921B2|2012-06-28|2014-07-22|Corning Incorporated|Methods of making a honeycomb structure|
    US8959793B2|2013-03-14|2015-02-24|International Thermal Systems, Inc.|Pin oven with a continuous U-shaped duct|
    US9126869B1|2013-03-15|2015-09-08|Ibiden Co., Ltd.|Method for manufacturing aluminum-titanate-based ceramic honeycomb structure|
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    CN104132508A|2014-07-31|2014-11-05|广西北流仲礼瓷业有限公司|Ceramic product drying device|
    JP6291447B2|2015-03-31|2018-03-14|日本碍子株式会社|Microwave drying method for honeycomb molded body|
    JP6295226B2|2015-03-31|2018-03-14|日本碍子株式会社|Microwave drying method for honeycomb molded body|
    JP2019014038A|2015-11-25|2019-01-31|住友化学株式会社|Method for drying green body and method for producing honeycomb structure|
    JP6562960B2|2017-03-28|2019-08-21|日本碍子株式会社|Manufacturing method of honeycomb structure|
    JP6559727B2|2017-03-28|2019-08-14|日本碍子株式会社|Manufacturing method of honeycomb structure|
    法律状态:
    2011-02-28| RE| Patent lapsed|Effective date: 20100831 |
    优先权:
    申请号 | 申请日 | 专利标题
    JP2004248216|2004-08-27|
    JP2004248216|2004-08-27|
    JP2005148379A|JP4745722B2|2004-08-27|2005-05-20|Microwave drying method for honeycomb molded body|
    JP2005148379|2005-05-20|
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