JP4615263B2 - Substrate coating apparatus and method - Google Patents

Description

  The present invention relates to a substrate coating apparatus and method for extending a slurry in a large number of flow paths formed in parallel to a base material to cover the inner walls of the flow paths, and more particularly to a monolith that serves as a catalyst base material for an exhaust gas purification catalyst. It is suitable for forming a catalyst by coating the catalyst slurry on the inner wall of the honeycomb flow path formed in the above.

A wash coat method is known as a method of coating a catalyst slurry on the inner wall of a honeycomb flow channel formed in a monolith that becomes a catalyst substrate.
Japanese Unexamined Patent Publication No. 63-51949 Japanese translation of PCT publication No. 2002-506720

FIG. 5 shows a coating apparatus using such a conventional wash coat method, in which a slurry supply device is provided in a reservoir 52 formed on the upper end side of a monolith M in which honeycomb channels 51... The slurry S is supplied from 53 and pressurized air is supplied from the upper end side, or air is sucked from the lower end side so that the slurry flows in / extends into the flow path 51 to cover the inner wall of the flow path 51. I have to.
Recently, noble metals such as platinum may be contained in the slurry S, and only the necessary amount of the slurry S used for coating the monolith M is supplied to the storage unit 52.

  By the way, since the slurry S has a high viscosity, the slurry supply nozzle 54 needs to have a certain thickness, but is preferably as thin as possible in order to strictly control the supply amount. And if a highly viscous slurry is supplied to the storage part 52 from such a supply nozzle 54, the slurry S will be stored in the state where the right under the supply nozzle 54 rose (refer Fig.6 (a)).

In this state, when pressurized air is supplied from the upper end side or air is sucked from the lower end side, the slurry S initially flows uniformly into each flow path 51 (see FIG. 6B).
Since the amount of the slurry S is large in the central portion and small in the peripheral portion, even if the slurry S in the peripheral portion finishes flowing into the honeycomb flow channel 51A in the peripheral portion, the slurry still flows into the honeycomb flow channel 51B in the central portion. I will do it.

  Then, by sucking air from the lower end side, when the slurry is finally extended into the honeycomb flow channel 51 to be coated, the coating length is larger than the honeycomb flow channel 51A at the peripheral portion. The covering length of the channel 51B becomes long (see FIG. 6C).

Therefore, for example, when a necessary amount of slurry is supplied so as to cover the slurry S up to half the length of the honeycomb flow channel 51, the peripheral portion of the honeycomb flow channel 51A is covered only by half or less, and the central portion of the honeycomb flow channel 51A is covered. The flow path 51B is covered with more than half of the length, and the covering length becomes non-uniform.
Similarly, when only a necessary amount of slurry S used for coating the monolith M is supplied, a sufficient amount of slurry S does not flow into the honeycomb channel 51A at the peripheral portion, so that the honeycomb channel 51A covers the lower end. However, there is a problem that the excess slurry S flows out from the honeycomb flow path 51B in the central portion (see FIG. 6D).

  For this reason, in order to uniformly coat the slurry S over the entire length of each of the honeycomb channels 51, a considerably larger amount of the slurry S than the necessary amount used for coating the monolith M is supplied to the reservoir 52, and all the honeycomb channels 51 are supplied. 51, the slurry S must be excessively filled and the surplus slurry S must be wiped away. The surplus slurry S that has been wiped off is recovered, and the components are adjusted and recycled. It was necessary and time-consuming.

  Therefore, as a technical problem, the present invention provides a technique for uniformly covering all the channels formed in the base material without waste when the necessary amount of slurry used for coating is supplied without excess or deficiency. Yes.

The present invention provides a substrate coating apparatus for extending the slurry supplied to one end side of a base material in which a large number of flow paths are formed in parallel into the flow path by air pressure to cover the inner wall of the flow path.
A slurry supply device for supplying a required amount of slurry to a slurry reservoir formed on the upper surface of a base material arranged so that both ends of the flow channel open to the upper surface and the bottom surface, and the slurry into the flow channel A leveling mechanism that makes the slurry level uniform before extending, and the gravity of the slurry to flow into each flow path from the slurry reservoir and the atmospheric pressure in the flow path are adjusted to adjust the slurry level. It is characterized by having an atmospheric pressure adjusting mechanism that switches between preventing inflow and extension .

According to the substrate coating apparatus according to the present invention, the slurry is supplied from the slurry supply device to the slurry storage portion formed on the upper surface of the substrate arranged so that both ends of the flow path open to the upper surface and the bottom surface. After the required amount is supplied and the slurry liquid surface is made uniform by the liquid surface equalizing mechanism, the slurry is extended into the flow path.
That is, the slurry supplied from the slurry supply device is raised in a mountain shape at the slurry storage portion at that time, but before the slurry is extended into the flow path, for example, the base material Is rotated around the vertical axis of the penetrating or the stored slurry is vibrated to make the slurry liquid level uniform.

In this way, after the liquid level is made uniform in the reservoir, pressurized air is applied from the upper end side, air is sucked from the lower end side, or in some cases, pressurization and suction are performed simultaneously, If the slurry is caused to flow into each flow path, the liquid level position with respect to each flow path is equal at that time, so the same amount of slurry flows into each flow path.
Therefore, for example, when the slurry is to be coated over the entire length of each flow path, an appropriate amount of slurry flows into each flow path even when the required amount of slurry used for coating is supplied to the reservoir without excess or deficiency. Because it is extended, any flow path can cover the slurry over its entire length.

Further, the slurry generally has a viscosity that does not flow into the flow path as it is, but some of the slurry is low enough to flow into the flow path only by gravity.
Therefore, even when such a slurry is used, the gravity and flow path of the slurry that is going to flow into each flow path from the slurry reservoir so that the slurry does not flow into each flow path before making the liquid level uniform. An atmospheric pressure adjusting mechanism that adjusts the atmospheric pressure inside and switches between blocking and extending the slurry into the flow path is provided .

  As the air pressure adjusting mechanism, as described in claim 5, an air handling device is used in which air is supplied / suctioned from the bottom surface side of the base material to apply positive / negative pressure in each flow path. Or a removable packing that seals the channel opening on the bottom side of the substrate, and air in the channel is sucked and / or applied from the liquid surface side of the slurry reservoir with the packing open. An air handling device that supplies compressed air is used.

  In this example, the problem of allowing a highly viscous slurry to flow uniformly into any flow path without any waste and coating can be realized with a simple configuration.

  FIG. 1 is an explanatory diagram showing an example of a substrate coating apparatus according to the present invention, FIG. 2 is a process diagram showing an example of a substrate coating method according to the present invention, and FIGS. 3 and 4 are explanatory diagrams showing other embodiments. It is.

  A substrate coating apparatus 1 shown in FIG. 1 has a slurry slurry S flowing in and extended by air pressure into a large number of honeycomb channels 2 formed in parallel with a monolith (catalyst substrate) M to form an inner wall 2w of the honeycomb channel. It is for coating and producing an exhaust gas purifying catalyst.

  The substrate coating apparatus 1 includes an apparatus main body 3 for fixing the monolith M so that both ends of the honeycomb flow paths 2 open to the upper surface and the bottom surface, and a slurry storage unit 5 having an attachment 4 attached to the upper end of the monolith M. Slurry supply device 6 for supplying a required amount of slurry S, liquid level homogenizing mechanism 7 for making the slurry liquid level uniform, and slurry S to be flowed into each flow path 2 from the slurry reservoir 5. An atmospheric pressure adjusting mechanism 8 is provided for adjusting the gravity and the atmospheric pressure in the flow path 2 to switch the blocking and extension of the slurry S into the flow path 2.

In the apparatus main body 3, the ceiling surface of the air chamber 9 whose internal pressure is controlled by the atmospheric pressure adjustment mechanism 8 is formed by a rotary table (base material rotation mechanism) 10 that supports the monolith M in a rotatable manner.
The rotary table 10 has gear teeth 10a formed on the outer peripheral surface thereof engaged with the gear teeth 12a of the drive gear 12 driven by the motor 11, so that the monolith M can be rotatably mounted around its penetrating vertical axis. By rotating the slurry S in a state in which the slurry S is stored in the slurry storage unit 5, the liquid level equalizing mechanism 7 is configured to make the slurry liquid level uniform using the centrifugal force.
The monolith M is fitted into a through hole 10b formed in the turntable 10 so that the upper end of the honeycomb flow path 2 is opened outside the air chamber 9 and the lower end is opened in the air chamber 9. It is fixed with.

The attachment 4 serving as the slurry reservoir 5 is formed with a frustoconical surface whose lower end is formed and fitted in the same shape and size as the upper end surface of the monolith M and gradually expands toward the upper end side. .
The slurry supply device 6 is set to accurately measure and supply a predetermined amount of the slurry S.

  The air pressure adjusting mechanism 8 includes an air handling device 13 that supplies / suctions air to apply positive / negative pressure in each flow path 2... More specifically, the air pressure adjusting mechanism 8 performs air suction / discharge. An air pump 14 and a switching valve CV for switching supply / suction of air to the air chamber 9 are provided.

The switching valve CV is a suction side 14in and discharge side 14out of the air pump 14, made of a three-position valve for switching and connecting to the atmosphere opening port 15 and the air supply and exhaust pipe 16, drawn in from the air vent port 15 in the first position P ₁ The air is supplied to the air chamber 9 to apply a positive pressure to the flow paths 2... And the supply / exhaust pipe 16 is shut off at the second position P ₂ to maintain the internal pressure of the air chamber 9, and the third position P _3. Thus, the air in the air chamber 9 is forcibly discharged to apply a negative pressure to the flow paths 2.
In addition, a relief valve 18 is interposed in the pipe 17 branched from the air supply / exhaust pipe 16, and is opened when the internal pressure of the air chamber 9 exceeds the set pressure to release the internal air, and the internal pressure is maintained at the set pressure. It is made to do.

The above is an example of the configuration of the present invention. Next, the case where the catalyst substrate is coated with the slurry by the substrate coating method according to the present invention will be described.
First, in a state where the attachment 4 is mounted on the monolith M serving as the catalyst base, this is fixed to the turntable 10.
In the slurry supply step, as shown in FIG. 2 (a), the minimum required amount used when the slurry S is coated over the entire length of all the honeycomb flow paths 2 from the slurry supply device 6 to the slurry reservoir 5. Although the slurry S is supplied, since the slurry S has a certain degree of viscosity, it is raised to the slurry reservoir 5.
Incidentally, the same time, sets the switching valve CV of the air pressure adjusting mechanism 8 in the first position P _1, by supplying air to the air chamber 9, the flow to the extent that the slurry S does not flow into the honeycomb channels 2 ... road 2 ... reacted with positive pressure to then be set changeover valve CV to the second position P _2, even stop the air pump 14 positive pressure of each flow path 2 ... it is maintained.

Next, in the liquid level homogenizing step, as shown in FIG. 2B, when the rotary table 10 of the liquid level equalizing mechanism 7 is rotated at an appropriate number of revolutions, the monolith M and the attachment attached to the upper end portion thereof. 4 rotates, a centrifugal force acts on the slurry S stored in the slurry storage unit 5, and the slurry S whose center portion has risen spreads around.
Then, when the liquid surface becomes substantially uniform, the rotation of the turntable 10 is stopped.
During this time, since the inside of the honeycomb flow paths 2 is maintained at a positive pressure, the slurry S does not flow in.

Then, the slurry extension step, by sucking the air in the air chamber 9 by setting the switching valve CV of the air pressure adjusting mechanism 8 in the third position P _3, as shown in FIG. 2 (c), the slurry S It flows into the honeycomb flow path 2.
At this time, since the liquid level is uniform (horizontal), the slurry S similarly flows into each flow path 2..., And all the slurry S stored in the storage unit 5 flows into each flow path. At that time, as shown in FIG. 2 (d), the slurry S is clogged in the respective flow paths 2 by the same length.

Furthermore, when the air in the air chamber 9 is sucked, the slurry S clogged in each flow path 2 is extended along the flow path inner wall 2w, and the slurry S can originally cover the entire length of all the honeycomb flow paths 2. Since the minimum required amount is supplied, as shown in FIG. 2 (e), the entire length of both the honeycomb channel 2A at the peripheral portion of the monolith M and the honeycomb channel 2B at the central portion are covered.
In addition, not only when covering the full length, but when covering only a predetermined length such as 1/2, 2/3 of the full length, for example, the supply amount to the slurry reservoir 5 according to the coating length Can be adjusted.

FIG. 3 shows another embodiment of the present invention. In this example, when the slurry liquid surface is made uniform, a centrifugal force is not applied, but a vibration is applied. In addition, about the part which overlaps with FIG. 1, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.
The substrate coating apparatus 21 of the present example is such that both ends of the honeycomb flow paths 2 open to the top and bottom surfaces of the ceiling of the apparatus main body 22 in which the air chamber 9 in which the internal pressure is controlled by the atmospheric pressure adjusting mechanism 8 is formed. A table 23 for fixing the monolith M is provided.
The liquid level equalizing mechanism 7 includes a vibrator (oscillation mechanism) 24 attached to the outer peripheral surface of the attachment 4 attached to the upper end of the monolith M. The slurry S stored in a raised state is subjected to low-frequency vibration and high-frequency vibration. The liquid surface is made uniform by vibrating with ultrasonic vibration or the like.
Note that the vibrator 24 may be attached to the apparatus main body 22. In short, it is sufficient that vibration is transmitted to the slurry S stored in the slurry storage unit 5.

FIG. 4 shows still another embodiment, and in this example, the atmospheric pressure can be adjusted without supplying air to the honeycomb channels 2. Note that parts common to those in FIG.
The base material coating apparatus 31 of this example includes, as the atmospheric pressure adjusting mechanism 8, an detachable packing 32 that seals the opening on the bottom surface side of the honeycomb flow path 2, and the air chamber 9 with the packing 32 opened. An air handling device 34 including an air pump 33 that sucks air in the honeycomb flow paths 2.
In the packing 32, a lifting base 35 disposed so as to be movable up and down in the air chamber 9 is rotatably attached to a lifting shaft 36, and a soft rubber 38 is attached to the surface side of the base 35 via a sponge-like elastic body 37. The opening of the honeycomb flow path 2 is sealed with this soft rubber 38.

  According to this, if the packing 32 is brought into close contact with the monolith M and the bottom opening of the flow path 2 is closed in the slurry supply step and the liquid level homogenization step, the slurry S supplied to the slurry storage portion 5 becomes the honeycomb. Even if it tries to flow into the flow paths 2..., The flow of the slurry S is reliably prevented by the pressure of the air confined in each flow path 2.

  In the slurry extending step, after the packing 32 is lowered, if the air pump 33 of the air handling device 34 is started, the air in the honeycomb flow path 2 is sucked through the air chamber 9 and the slurry S is respectively discharged. Uniformly flow into the honeycomb flow paths 2.

In the above description, the case where the air in the honeycomb flow path 2 is sucked through the air chamber 9 using the air handling devices 13 and 34 in any of the slurry extending steps has been described. Not only this but the case where pressurized air is supplied from the liquid surface side of the slurry storage part 5 or the case where both of these are performed may be sufficient.
Further, the case where the catalyst slurry is coated on the monolith M, which is the catalyst substrate, has been described. However, the present invention is not limited to this, and the slurry may be coated on the inner walls of a large number of flow paths formed in parallel on the substrate. Can be used for various purposes.

  As described above, according to the present invention, since the slurry liquid level supplied to the slurry reservoir is made uniform, the slurry is caused to flow into each flow path. A great amount of slurry flows in, and all channels can be coated uniformly with the same length of slurry, and at the same time, even when the slurry is coated over the entire length of the channel, waste of slurry occurs. It has a very good effect.

  INDUSTRIAL APPLICABILITY The present invention can be applied to an application in which slurry is extended into a large number of flow paths formed in parallel to a base material to cover the inner wall of the flow path, and is particularly formed in a monolith that becomes a catalyst base material for an exhaust gas purification catalyst. It is suitable for use in forming a catalyst by coating the inner wall of the honeycomb flow path with a slurry for catalyst.

Explanatory drawing which shows an example of the base-material coating apparatus which concerns on this invention. Explanatory drawing which shows an example of the base-material coating method concerning this invention. Explanatory drawing which shows other embodiment. Explanatory drawing which shows other embodiment. Explanatory drawing which shows a conventional apparatus. Explanatory drawing which shows a conventional method.

Explanation of symbols

1 Substrate coating device M Monolith (catalyst substrate)
S Slurry for catalyst
2 Honeycomb channel 2w Channel inner wall
DESCRIPTION OF SYMBOLS 3 Apparatus main body 4 Attachment 5 Slurry storage part 6 Slurry supply apparatus 7 Liquid level equalization mechanism 8 Air pressure adjustment mechanism 9 Air chamber 10 Rotary table (base material rotation mechanism)
13 Air handling device

Claims (7)

In the substrate coating apparatus for coating the inner wall of the flow path by extending the slurry supplied to one end side of the base material in which a large number of flow paths are formed in parallel with the air pressure,
A slurry supply device for supplying a required amount of slurry to a slurry reservoir formed on the upper surface of a base material arranged so that both ends of the flow channel open to the upper surface and the bottom surface, and the slurry into the flow channel A leveling mechanism that makes the slurry level uniform before extending, and the gravity of the slurry to flow into each flow path from the slurry reservoir and the atmospheric pressure in the flow path are adjusted to adjust the slurry level. A substrate coating apparatus comprising an atmospheric pressure adjusting mechanism that switches between prevention of inflow and extension .   The substrate coating apparatus according to claim 1, wherein the liquid surface equalizing mechanism is a substrate rotating mechanism that rotates the substrate around a penetrating vertical axis.   The substrate coating apparatus according to claim 1, wherein the liquid level uniformizing mechanism is an oscillation mechanism that vibrates the slurry stored in the slurry storage unit. 2. The substrate coating apparatus according to claim 1, wherein an air handling device that supplies / suctions air from the bottom surface side of the substrate and applies positive / negative pressure in each flow path is used as the atmospheric pressure adjusting mechanism. As the atmospheric pressure adjusting mechanism, a detachable packing that seals the flow path opening on the bottom surface side of the base material, and the air in the flow path is sucked with the packing opened, and / or the liquid in the slurry storage section 2. The substrate coating apparatus according to claim 1, wherein an air handling apparatus for supplying pressurized air from the surface side is used. In the substrate coating method of coating the inner wall of the flow path by extending the slurry supplied to one end side of the base material in which a large number of flow paths are formed in parallel with the air pressure,
A slurry supply step for supplying a required amount of slurry to a slurry reservoir formed on the upper surface of a base material arranged such that both ends of the flow channel are open to the upper surface and the bottom surface, and the slurry into the flow channel A liquid leveling process for making the slurry liquid level uniform before extending ,
In the slurry supply step and the liquid level equalization step, the base material coating is characterized in that the gravity of the slurry to be flown into each flow path from the slurry reservoir and the atmospheric pressure in the flow path are maintained in a balanced state. Method. A catalyst is formed by coating a catalyst slurry on the inner wall of a flow path of the catalyst base by using a catalyst base having a plurality of flow paths formed in parallel as the base and using a catalyst slurry as the slurry. Item 7. The substrate coating method according to Item 6 .

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