JP6177570B2 - Slurry coating device - Google Patents

Description

  The present invention relates to an apparatus for applying a slurry to a honeycomb substrate.

  Exhaust gas discharged from an internal combustion engine such as an engine contains harmful substances such as hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx). Since these substances cause air pollution, it is necessary to purify the exhaust gas.

  In order to purify the exhaust gas, an exhaust gas purifying catalyst in which a slurry containing a catalytic metal is applied to the cell walls constituting the cells of the honeycomb substrate is used. Examples of the apparatus for applying the slurry to the honeycomb substrate include those described in Patent Documents 1 and 2.

  Patent Document 1 discloses an apparatus for applying a slurry to a substrate by immersing the lower end surface of the substrate in a slurry accommodated in a dipping pan and sucking the slurry from the upper end surface of the substrate using a vacuum. ing. Patent document 2 is disclosing the apparatus which apply | coats a slurry to a base material by attracting | sucking the slurry supplied to the upper end surface of the base material from the lower end surface of a base material using a vacuum.

JP-A-8-103667 Japanese translation of PCT publication No. 2002-506720

  However, in the apparatus described in Patent Document 1, since the base material is immersed in the slurry, the slurry adheres to the outer surface of the base material. Since the slurry adhering to the outer surface does not function effectively for exhaust gas purification, some of the slurry is wasted. Further, in the system in which the slurry is sucked upward from the lower end surface of the substrate, it is difficult to suck all the slurry. As a result, the remaining slurry is reused, and the operation becomes complicated. Furthermore, since the force for sucking the slurry is different in each cell, it is difficult to uniformly control the coating width of the slurry in each cell.

  In the apparatus described in Patent Document 2, since the degree of vacuum used for sucking the slurry is not controlled, it is difficult to control the coating width of the slurry. It is also difficult to uniformly control the slurry coating width in each cell. Furthermore, depending on the degree of vacuum, the slurry supplied to the upper end surface of the base material may leak out from the lower end surface.

  Therefore, an object of the present invention is to provide a new apparatus for solving the above-described problems. In particular, an object of the present invention is to provide an apparatus capable of uniformly controlling the slurry coating width in each cell of a honeycomb substrate.

  As a result of intensive studies by the present inventors, a vacuum state is formed in advance using a vacuum tank, and the slurry supplied to the upper end surface of the honeycomb substrate is used as the lower end surface of the substrate using the vacuum state. It was found that the coating width of the slurry in each cell can be uniformly controlled by instantaneously sucking.

  That is, the present invention includes the following.

[1] An apparatus for applying a slurry to a cell wall constituting a cell of a honeycomb substrate having a plurality of cells,
A suction part in which the lower end face of the honeycomb base material is disposed and sucks the slurry supplied to the upper end face of the honeycomb base material;
A vacuum tank connected to the suction section;
An on-off valve installed between the suction part and the vacuum tank; and vacuum forming means for bringing the inside of the vacuum tank into a vacuum state;
With
With the open / close valve closed, the vacuum forming means evacuates the vacuum tank and opens the open / close valve so that the suction part sucks the slurry supplied to the upper end face of the honeycomb substrate. An apparatus for applying a slurry to the cell wall.

[2] The apparatus according to [1], further including a pressure sensor that detects a pressure inside the vacuum tank.

[3] The apparatus according to [1] or [2], further comprising a pressure release valve that adjusts the pressure inside the vacuum tank.

[4] When the pressure inside the vacuum tank detected by the pressure sensor exceeds a certain value, the pressure is reduced by the vacuum forming means, or the pressure inside the vacuum tank detected by the pressure sensor is constant. The apparatus according to [3], further comprising control means for controlling the pressure inside the vacuum tank so that the pressure is increased by the pressure release valve when the value is below the value.

  According to the present invention, the slurry coating width in each cell can be controlled uniformly.

1 shows an embodiment of a device according to the invention. One embodiment of a suction part is shown. One embodiment of a suction part is shown. 1 shows an embodiment of a device according to the invention. 1 shows an embodiment of a device according to the invention. 1 shows an embodiment of a device according to the invention. The conventional slurry application apparatus is shown.

  Hereinafter, a slurry coating apparatus according to the present invention will be described with reference to the drawings.

  In one embodiment of the present invention, for example, as shown in FIG. 1, the slurry application device includes a suction unit 1, an opening / closing valve 2, a pipe 3, a vacuum tank 4, and a vacuum forming means 5. The honeycomb base material 11 is disposed above the suction part 1.

  The suction unit 1 is connected to a vacuum tank 4 via an opening / closing valve 2 and a pipe 3. The inside of the vacuum tank 4 can be evacuated by the vacuum forming means 5. In the present specification, the “vacuum state” means a state where the pressure is lower than the surrounding environment, for example, −5 to −70 kPa (relative pressure).

  The upper part of the suction part 1 has an inner diameter (X in FIG. 1) in which the entire lower end face of the honeycomb substrate 11 can be arranged. Although the preferable internal diameter of the suction part 1 changes with the magnitude | sizes of a base material, it is preferable that it is 70-280 mm, for example. By making the inner diameter 70 mm or more, it is possible to avoid the slurry being sucked by an excessive force. This makes it easy to control the coat width. Moreover, since a slurry is attracted | sucked by moderate force because an internal diameter shall be 280 mm or less, a coat width can be expanded to desired length. When the inner diameter of the suction part 1 is larger than the outer diameter of the lower end surface of the honeycomb base material 11, packing or the like is used so that air does not flow into the suction part 1 from the outer peripheral region of the honeycomb base material 11. Is preferred.

  The upper part of the suction part 1 that contacts the lower end surface of the honeycomb substrate 11 needs to have a predetermined inner diameter as described above, but the inner diameter of the lower part of the suction part 1 is not particularly limited. For example, the inner diameter of the lower part may be smaller (FIG. 2), the same (FIG. 3), or larger (not shown) than the inner diameter of the upper part.

  Although the linear distance (Y of FIG. 1) from the upper end of the suction part 1 to the lower end is not particularly limited, for example, it is preferably 500 to 2000 mm, and more preferably 800 to 1200 mm. By setting the linear distance to 500 mm or more, a uniform static pressure is applied to the entire lower liquid surface of the slurry of the honeycomb substrate 11, and the slurry can be sucked more uniformly in each cell. Further, by setting the linear distance to 2000 mm or less, the volume of the suction unit 1 can be reduced and the slurry can be sufficiently sucked.

  Although the volume of the suction part 1 is not specifically limited, For example, it is preferable that it is 2-35L. By setting the volume to 2 L or more, a uniform static pressure is applied to the entire lower liquid surface of the slurry of the honeycomb substrate 11, and the slurry can be sucked more uniformly in each cell. Further, by setting the volume to 35 L or less, a sufficient static pressure can be secured and the slurry can be sufficiently sucked, so that the coat width can be expanded to a desired length.

  The vacuum tank 4 can withstand a vacuum state, and preferably withstands a pressure of -70 kPa (relative pressure). Although the volume of the vacuum tank 4 is not specifically limited, For example, it is preferable that it is 100-1500L. Further, the volume of the space (hereinafter referred to as “vacuum part”) (Z in FIG. 1) between the opening / closing valve 2 and the vacuum forming means 5 is not particularly limited, but is preferably 200 to 2000 L. By setting the volume of the vacuum tank 4 or the vacuum part to 100 L or 200 L or more, a vacuum state capable of sufficiently sucking the slurry can be ensured. Further, by setting the volume of the vacuum tank 4 or the vacuum part to 1500 L or 2000 L or less, respectively, the slurry suction time is shortened, and the control of the coat width is facilitated.

  The vacuum forming means 5 is not particularly limited as long as the inside of the vacuum tank 4 can be evacuated. For example, a roots blower, an ejector, etc. can be mentioned.

  In the apparatus configured as shown in FIG. 1, the inside of the vacuum tank 4 is evacuated by the vacuum forming means 5 with the open / close valve 2 closed. On the other hand, the lower end face of the honeycomb base material 11 is disposed in the upper part of the suction part 1, and slurry is supplied to the upper end face of the base material. Next, by opening the on-off valve 2, the slurry is sucked by the pressure difference between the vacuum part and the suction part. In this method, since the slurry can be instantaneously sucked using a large pressure difference, the slurry can be sucked uniformly through each cell of the substrate. As a result, the slurry can be applied to each cell wall with a uniform length. Moreover, the coating width of the slurry can be adjusted to a desired length by appropriately adjusting the pressure inside the vacuum tank 4. Furthermore, since the slurry can be sucked rapidly by utilizing a high vacuum state, the slurry can be applied in a short time. That is, the production efficiency of the exhaust gas purification catalyst can be increased.

  Moreover, as shown in FIG. 4, in one embodiment of the present invention, the slurry application device may further include a pressure sensor 6 that detects the pressure inside the vacuum tank 4. By providing the pressure sensor 6, it is possible to accurately ensure a vacuum state in which a desired coat width can be realized. In addition, the slurry application device may further include a pressure release valve 7 that adjusts the pressure inside the vacuum tank 4. By providing the pressure release valve 7 together with the vacuum forming means 5, the pressure inside the vacuum tank 4 can be easily adjusted.

  Further, as shown in FIG. 5, in one embodiment of the present invention, the slurry application device includes a vacuum forming means 5 and a pressure release valve based on the pressure inside the vacuum tank 4 detected by a pressure sensor 6 installed arbitrarily. Control means 8 for controlling 7 may be further provided. When the pressure inside the vacuum tank 4 detected by the pressure sensor 6 exceeds a certain value, the control means 8 performs control such that the vacuum forming means 5 is activated to lower the pressure. On the other hand, when the pressure inside the vacuum tank 4 detected by the pressure sensor 6 falls below a certain value, the control means 8 performs control to open the pressure release valve 7 and increase the pressure. An example of the control means 8 is a computer. The functions of the control means 8 can be realized by operating programs stored in the RAM, HDD, etc. of the computer.

  Further, as shown in FIG. 6, in one embodiment of the present invention, the slurry application device may further include a fixing means 9 for fixing the honeycomb substrate 11. Examples of the fixing means 9 include a lower jig.

  The slurry coating apparatus may further include a holding unit 10 that holds the slurry 12 on the upper end surface of the honeycomb substrate 11. It is preferable that the holding means 10 has a structure capable of being in liquid-tight contact with the honeycomb substrate 11. An example of the holding means 10 is an upper jig.

  The slurry coating apparatus may further include a supply unit 13 that supplies the slurry 12 to the upper end surface of the honeycomb substrate 11. The supply means 13 preferably has a structure that can uniformly supply the slurry 12 to the upper end face of the honeycomb substrate 11. Examples of the supply means 13 include a shower type nozzle.

  The slurry application device may further include a leveling means (not shown) for leveling the slurry 12 supplied to the upper end surface of the honeycomb substrate 11. Examples of the leveling means include a rotating device that rotates the honeycomb base material 11 with the slurry 12 supplied to the upper end surface about the axial direction.

  The slurry coating apparatus may further include a damper (not shown) between the suction unit and the vacuum unit. By providing the damper, the suction force when the opening / closing valve 2 is opened can be adjusted.

  In addition, although not shown, the slurry application device may include a plurality of vacuum tanks. For example, a plurality of vacuum tanks may be respectively connected to a plurality of corresponding vacuum forming means, or may be connected to a single vacuum forming means. Further, a further vacuum tank may be connected to the vacuum tank connected to the vacuum forming means. In the case where a plurality of vacuum tanks are provided, it is preferable to provide a valve or the like so that the vacuum tanks can be shut off. In the apparatus configured as described above, a plurality of vacuum tanks can be used as necessary, so that even if the contents required in the application of the slurry change variously, it is possible to flexibly cope with it.

  In addition, the kind of slurry is not specifically limited. Generally, a slurry containing a catalyst metal (for example, palladium, platinum, rhodium), a support (for example, alumina, ceria), a solvent (for example, water) and the like is used.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example and a comparative example, the technical scope of this invention is not limited to this.

  The slurry was apply | coated to the cell wall of the honeycomb base material using the slurry application | coating apparatus which concerns on this invention (Examples 1-3). In Examples 1 to 3, the slurry was sucked using various vacuum conditions. Moreover, the slurry was apply | coated to the cell wall of the honeycomb base material using the conventional slurry application apparatus (FIG. 7) (Comparative Examples 1 and 2). A conventional slurry application apparatus does not use a vacuum tank but sucks slurry using a turbo blower 14. The suction conditions and the suction results are shown in Table 1 and Table 2, respectively.

  As shown in Tables 1 and 2, by using the slurry coating apparatus according to the present invention, the suction time can be shortened. Further, the coating width of the slurry can be controlled by adjusting the pressure inside the vacuum tank. Furthermore, the coat width in each cell can be controlled uniformly. On the other hand, in the conventional slurry coating apparatus, it is difficult to uniformly control the coating width in each cell. Further, even under the same suction conditions, the coat width is greatly different.

1 .... Suction part 2 .... Open / close valve 3 .... Piping 4 .... Vacuum tank 5 .... Vacuum forming means 6 .... Pressure sensor 7 .... Pressure release valve 8 .... Control means 9 .. Fixing means, 10 .. Holding means, 11 .. Honeycomb base material, 12 .. Slurry, 13 .. Supply means, 14 .. Turbo blower

Claims (2)

An apparatus for applying a slurry to a cell wall constituting a cell of a honeycomb substrate having a plurality of cells,
A suction part in which the lower end face of the honeycomb base material is disposed and sucks the slurry supplied to the upper end face of the honeycomb base material;
A vacuum tank connected to the suction section;
An open / close valve installed between the suction part and the vacuum tank;
Means for forming a vacuum in the vacuum tank ;
A pressure sensor provided in the vacuum tank for detecting the pressure inside the vacuum tank; and
A pressure release valve provided in the vacuum tank, for adjusting a pressure inside the vacuum tank;
With
With the open / close valve closed, the vacuum forming means evacuates the vacuum tank and opens the open / close valve so that the suction part sucks the slurry supplied to the upper end face of the honeycomb substrate. An apparatus for applying a slurry to the cell wall. When the pressure inside the vacuum tank detected by the pressure sensor exceeds a certain value, the pressure is reduced by the vacuum forming means, or the pressure inside the vacuum tank detected by the pressure sensor falls below a certain value. in this case, to increase the pressure by the pressure relief valve, further comprising a control means for controlling the pressure inside the vacuum tank apparatus according to claim 1.

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