EP2233263B1

EP2233263B1 - Slurry ejection apparatus, slurry application apparatus, and method for manufacturing plugged honeycomb structure

Info

Publication number: EP2233263B1
Application number: EP20100250533
Authority: EP
Inventors: Naoto Kouketsu; Hiroshi Furukubo; Yoshinori Mizuno
Original assignee: NGK Insulators Ltd; NGK Ceramic Device Co Ltd
Current assignee: NGK Insulators Ltd; NGK Ceramic Device Co Ltd
Priority date: 2009-03-26
Filing date: 2010-03-22
Publication date: 2013-12-25
Anticipated expiration: 2030-03-22
Also published as: JP2010228263A; EP2233263A2; EP2233263A3; JP5361490B2

Abstract

A slurry ejection apparatus 1 includes: a container portion 2 containing slurry 10 therein and having a discharge port 20, a thrust-imparting portion 3 disposed in the container portion 2, and a nozzle portion 4 provided with a feed port 11 communicating with the discharge port 20 and a slit-shaped ejection port 12 for ejecting the slurry 10. The ejection port 12 is formed with a fixed length in the width direction 9 of the ejection port 12 in each position in a longitudinal direction 8 of the discharge port to almost uniformalize an ejection amount per unit time of the slurry 10 in each position in the longitudinal direction 8 of the ejection port.

Description

Background of the Invention

The present invention relates to a slurry ejection apparatus,aslurryapplication apparatus,and a method for manufacturing a plugged honeycomb structure.
Exhaust gas discharged from a diesel engine or the like contains a large amount of particulate matter (PM) containing soot (carbon graphite) and the like, and PM causes air pollution. On an exhaust system of a diesel engine or the like, a filter of a ceramic is mounted for trapping PM, and a plugged honeycomb structure is employed for the filter (see, e.g., JP-A-2001-269585 ).
In the plugged honeycomb structure, a plugging portion plugs an end portion of each of the cells extending through in the axial direction. In the plugged honeycomb structure, the cells having no plugging portions on the inlet side have plugging portions on the outlet side, and the cells having plugging portions on the inlet side have no plugging portions on the outlet side. The plugging portions are disposed in a checkerwise pattern when the plugged honeycomb structure is viewed from an end face. By such disposition of the plugging portions, in the plugged honeycomb structure, a target gas to be treated flows in cells from the inlet side, passes through the ceramic porous partition walls partitioning the cells with trapping PM, and is discharged from the outlet side of the other cells.
In manufacturing of a plugged honeycomb structure, a honeycomb formed article obtained by forming kneaded clay constituted of ceramic raw materials into a honeycomb shape is manufactured, and ceramic slurry (hereinbelow referred to as "slurry") is filled in end portions of cells of the honeycomb formed articles, followed by firing. In the case that a firing shrinkage ratio is different between the slurry and the honeycomb formed article, there is caused a difference in shrinkage ratio upon firing between the portions where the slurry is filled and the portions where no slurry is filled. Therefore, when the slurry is not filled into end portions of the cells with uniform depth, by uneven shrinkage upon firing, a plugged honeycomb structure having a crack or a strain therein is manufactured.
The cells having deep plugging have short f low passages to decrease the area of the partition walls where the target gas to be treated can pass, that is, the area of the filter. When there is a variance in depth of plugging, since the filter area also has a variance depending on the cells, a defect may easily be caused as trapping for the target gas to be treated is repeated.
As is understood from the above, filling the slurry in the ends of the cells of the honeycomb formed article with uniform depth is necessary for manufacturing of a plugged honeycomb structure having high quality. Since it is difficult and inefficient to fill the slurry in the cells individually, for filling of the slurry, there is employed a method where slurry is applied on a plate-shaped container (hereinbelow referred to as a "plate-shaped container") in a plane state to immerse an end face of the honeycomb formed article in the applied slurry (see, e.g., JP-A-2001-300922 ). In this method, in order to fill the slurry in the cells with uniform depth, a flat interface of the applied slurry is required. This is because slurry can be filled into the cells with uniform depth when an end face of the honeycomb formed article is immersed in the slurry so as to join the flat interface of the slurry.
However, since the slurry has viscosity, simple application of the slurry on the plate-shaped container causes unevenness on the interface of the slurry unlike the case of pouring water in a plate-shaped container to form a flat water interface. Therefore, there are some devices to apply slurry with a flat interface.
JP-A-2007-269007 discloses a method for applying slurry in a state of having a flat interface on a plate-shaped container. In this method, after slurry is ejected on a plate-shaped container, the plate-shaped container is rotated to spread the slurry toward the outer peripheral side of the plate-shaped container by a centrifugal force, and the interface of the slurry is made flat. In addition, JP-A-2007-269007 discloses a method for ejecting slurry by a monoaxial eccentric screw pump (mohno pump). The monoaxial eccentric screw pump has the advantage that slurry can be ejected continuously and quantitatively without pulsation.
However, in the method of JP-A-2007-269007 , an equipment is required for rotating the plate-shaped container. In addition, during the rotation of the plate-shaped container, the slurry-filling operation is in a standby state. Further, since the slurry leans on the peripheral side of the plate-shaped container by a centrifugal force depending on the rotation velocity or the time, there is a case that the interface of the slurry is not flat to make filling of the slurry into the cells with uniform depth impossible.
Since the slurry has viscosity, when there is a bias in the flow velocity or the flow amount, unevenness is easily caused on the interface of the slurry on the plate-shaped container. Since the monoaxial eccentric pump is provided with a mechanism of imparting thrust by a rotor having an eccentric motion, it is suitable to quantitatively eject slurry having viscosity. However, when a monoaxial eccentric screw pump is used for the ejection of slurry, since the monoaxial eccentric screw pump covers a part of the discharge port because of the aforementioned mechanism with changing the covered position with the passage of time (see Fig. 15), a change in the slurry flow amount is caused in each position with the passage of time. Therefore, when the monoaxial eccentric screw pump is used for the ejection of slurry, unevenness is caused on the interface of the slurry applied on the plate-shaped container in a flat state.
US 6,423,144 describes a coating method which has a running step of running a nozzle and/or a base material, a change step of changing discharge-port slit widths of said nozzle, and a coating step of discharging a coating solution from said slit and coating said base material with said coating solution; wherein said running step, change step, and coating step are executed by combining them.
US 5,795,601 describes a slurry tank which stores an inorganic slurry, including a funnel-shaped lower tank portion having a discharge port. A valve is positioned in the slurry tank above the discharge port and is complementary in shape to an inner surface of the funnel-shaped lower tank portion of the slurry tank. The valve can be moved by an actuator selectively out of the discharge port to allow the inorganic slurry to be discharged from the discharge port and into the discharge port to stop discharging the inorganic slurry from the discharge port. A proportional pump is connected to the discharge port for supplying the inorganic slurry at a constant rate to a mold for injection molding when the valve is moved out of the discharge port by the actuator. A cylinder is connected to the proportional pump for being supplied with the inorganic slurry from the proportional pump and the cylinder opens into the mold. A plunger movably disposed in the cylinder applies the desired pressure on the inorganic slurry from the cylinder into the mold.
US 5,046,666 upon which the preamble of claim 1 is based describes a metering dispenser system for delivering a fixed or variable measured quantity of a high viscosity material such as adhesives or sealants for application to a substrate. It uses an Archimedian screw pump having a stator formed with a spiral cavity therethrough, and a spiral rotor which is driven by a variable speed drive motor. The stator has a nozzle attached to its outlet end, the inlet end thereof being in fluid communication with a reservoir for the material. The dispenser system is adapted for use in combination with a robotic system so that the nozzle is manipulated thereby. The rotational speed of the drive motor is controlled in response to a signal representative of a nozzle velocity so that the nozzle can apply a ribbon of the material with a fixed width to the substrate despite nozzle velocity variations. When the nozzle is about to come to a stop, the drive motor is rotated in a reverse direction so as to cause the nozzle to stop discharging the material instantly.
JP 2009 056421 describes an applicator for applying a liquid such as an adhesive, a sealing material and a coating by pressurizing a vessel with a hand. The applicator comprises a vessel for containing the liquid and a nozzle attached to the opening of the vessel, wherein the nozzle has a structure which keeps the cross-section area of the inside of the nozzle gradually reduced from the junction with the vessel to an ejection port at the tip end of the nozzle, makes the tip end of the nozzle serve as a slit-like ejection port, and the centre part of the inside of the nozzle serve as the flow path of the liquid narrower than that on both sides curved inside, with a guide provided at one side end part or both end parts of the ejection port of the nozzle.

Summary of the Invention

In view of the aforementioned problems, the present invention aims to provide a slurry ejection apparatus for ejecting slurry with relaxing the bias in the flow velocity and the flow amount, a slurry application apparatus for applying slurry in a plane state so as to have a flat interface, and a method for manufacturing a plugged honeycomb structure, the method being capable of filling slurry in the cells with uniform depth.
As a result of the present inventors' earnest study centering around the configuration of the nozzle portion where the slurry is ejected in order to solve the aforementioned problems, they found a configuration of a nozzle portion where the slurry can be ejected almost uniformly, which led to the completion of the present invention. That is, according to the present invention, there are provided the following slurry ejection apparatus, slurry application apparatus, and method for manufacturing a plugged honeycomb structure.
[1] A slurry ejection apparatus comprising: a container portion containing slurry therein and having a discharge port for discharging the slurry, a thrust-imparting portion disposed in the container portion and extruding the slurry toward the discharge port, and a nozzle portion provided with a feed port communicating with the discharge port and allowing the slurry to flow into the nozzle portion and a slit-shaped ejection port for ejecting the slurry flowed into the nozzle portion; wherein the ejection port is formed with a fixed length in the width direction of the ejection port in each position in a longitudinal direction of the discharge port to almost uniformalize an ejection amount per unit time of the slurry in each position in the longitudinal direction of the ejection port.
Theslurryejectionapparatusaccording to [1], wherein the nozzle portion is provided with a tip portion to decrease a difference in a flow velocity of the slurry in each position in the longitudinal direction in the ejection port, and, in the tip portion, a flow passage having a slit-shaped cross section is formed to the ejection port to allow the slurry to flow continuously in the longitudinal direction.
Theslurryejectionapparatusaccording to [1] or [2], wherein the thrust-imparting portion allows the slurry to flow into the nozzle portion with generating a bias in the flow amount and the flow velocity.
Theslurryejectionapparatusaccording to any one of [1] to [3], wherein the thrust-imparting portion allows the slurry to flow into the nozzle portion with increasing an average flow amount in the center of the longitudinal direction and decreasing the average flow amount on end sides in the longitudinal direction, while the discharge port is partially covered with changing the position and area where the discharge port is covered with the passage of time, and the length in the width direction of the ejection port of the nozzle portion is the smallest in the center in the longitudinal direction and the largest in the ends or in the vicinity of the ends.
Theslurryejectionapparatusaccording to [4], wherein the thrust-imparting portion is a rotary capacity type monoaxial eccentric screw pump which continuously extrudes the slurry and which allows the slurry to flow into the nozzle portion with increasing the average flow amount of the slurry in the center in the longitudinal direction and decreasing the average flow amount of the slurry on the end sides in the longitudinal direction, and the length in the width direction of the ejection port of the nozzle portion is the smallest in the center in the longitudinal direction and the largest in the ends or in the vicinity of the ends.
Theslurryejectionapparatusaccording to any one of [1] to [5], wherein the length in the width direction of the ejection port of the nozzle portion is the smallest in the center in the longitudinal direction and the largest in the ends or in the vicinity of the ends.
A slurry application apparatus comprising: a slurry ejection apparatus according to any one of [1] to [6], and a storage portion having a flat bottom face and receiving the slurry ejected from the slurry ejection apparatus; wherein the nozzle portion is provided over the bottom face, the ejection port of the nozzle portion faces the bottom face, and the nozzle portion is movable at a fixed speed relatively with respect to the bottom face with ejecting the slurry from the ejection port to apply the slurry in a plane state on the bottom face.
[8] The slurry application apparatus according to [7], comprising a retentive member for retaining a shape of an interface of the slurry while suppressing a flow of the slurry after the slurry is applied on the bottom face, wherein the retentive member is detachable from the bottom face and has a ring-shaped wall portion for surrounding the slurry applied on the bottom face, and the wall portion is provided with a lower face to adhere to the bottom face.
[9] A method for manufacturing a plugged honeycomb structure, comprising: using a slurry application apparatus according to [7] or [8] to eject slurry from the slurry ejection apparatus of the slurry application apparatus to the bottom face of the storage portion of the slurry application apparatus, and after the slurry is applied on the bottom face in a plane state, immersing an end face where cells are open of a honeycomb formed article in the slurry to fill the slurry into the cells.
A slurry ejection apparatus of the present invention exhibits an effect in ejecting slurry with relaxing a bias in the flow velocity and the flow amount. A slurry application apparatus of the present invention exhibits an effect in applying slurry in a plane state to obtain a flat interface. A method for manufacturing a plugged honeycomb structure of the present invention exhibits an effect in filling slurry into the cells with uniform depth.

Brief Description of the Drawings

[Fig. 1] Fig. 1 is a view schematically showing a cross section of an embodiment of a slurry ejection apparatus of the present invention.
[Fig. 2] Fig. 2 is a perspective view of the nozzle portion of a slurry ejection apparatus of the present invention when seen from the ejection port side.
[Fig. 3] Fig. 3 is a plan view of the nozzle portion shown in Fig. 2 when seen from the ejection port side.
[Fig. 4A] Fig. 4A is a vertical cross-sectional view of the nozzle portion in the A-A' cross section along the longitudinal direction of the ejection port shown in Fig. 2.
[Fig. 4B] Fig. 4B is a vertical cross-sectional view of the nozzle portion in the B-B' cross section along the width direction of the ejection port shown in Fig. 2.
[Fig. 5] Fig. 5 is an enlarged view showing the ejection port in the plan view of Fig. 3.
[Fig. 6] Fig. 6 is an enlarged view showing a plan view of a rectangular ejection port.
[Fig. 7] Fig. 7 is a view schematically explaining the ejection amount per unit time of slurry in each position along the longitudinal direction of the ejection port of a slurry ejection apparatus of the present invention.
[Fig. 8] Fig. 8 is a view schematically explaining the ejection amount per unit time of slurry in each position along the longitudinal direction of the ejection port of a slurry ejection apparatus not belonging to the present invention.
[Fig. 9A] Fig. 9A is an enlarged plan view of an ejection port of a nozzle portion.
[Fig. 9B] Fig. 9B is an enlarged plan view of an ejection port of a nozzle portion.
[Fig. 9C] Fig. 9C is an enlarged plan view of an ejection port of a nozzle portion.
[Fig. 9D] Fig. 9D is an enlarged plan view of an ejection port of a nozzle portion.
[Fig. 10] Fig. 10 is a horizontal cross-sectional view of a nozzle portion in the C-C' cross section shown in Fig. 2, showing a cross section of the tip portion of the nozzle portion.
[Fig. 11] Fig. 11 is a schematic view of a slurryejection apparatus provided with a configuration where slurry is allowed to continuously flow to the ejection port in the longitudinal direction.
[Fig. 12] Fig. 12 is a schematic view of a slurryejection apparatus provided with a configuration where slurry is allowed to discontinuously flow in the longitudinal direction to the ejection port.
[Fig. 13A] Fig. 13A is a view schematically showing a flow velocity distribution of slurry along the longitudinal direction of the ejection port at the position U in Figs. 11 and 12.
[Fig. 13B] Fig. 13B is a view schematically showing a flow velocity distribution of slurry along the longitudinal direction of the ejection port at the position L in Fig. 11.
[Fig. 13C] Fig. 13C is a view schematically showing a flow velocity distribution of slurry along the longitudinal direction of the ejection port at the position L in Fig. 12.
[Fig. 14] Fig . 14 isavertical cross section of a container portion provided with an monoaxial eccentric screw pump therein as the thrust-imparting portion.
[Fig. 15] Fig. 15 is a horizontal cross section taken along the A-A' in Fig. 14 of the container portion provided with an monoaxial eccentric screw pump therein as the thrust-imparting portion.
[Fig. 16] Fig. 16 is a view schematically showing a slurry application apparatus of the present invention applying slurry.
[Fig. 17] Fig. 17 is a view of application of slurry shown in Fig. 16 when seen from the top side of the bottom face.
[Fig. 18] Fig. 18 is a view schematically showing a slurry application apparatus with a storage portion having a side wall of the present invention applying slurry.
[Fig. 19] Fig. 19 is a view schematically showing the application of the slurry shown in Fig. 18 when seen from the top side of the bottom face.
[Fig. 20] Fig. 20 is a front view (top) of an embodiment of a retentive member and a vertical cross-sectional view of a A-A' cross section.
[Fig. 21] Fig. 21 is a plan view of a storage portion, schematically showing the retentive member suppressing the flow of the slurry applied on the bottom face when seen from the top.
[Fig. 22] Fig. 22 is a vertical cross-sectional view along the A-A' of the storage portion and the retentive member shown in Fig. 21.
[Fig. 23] Fig. 23 is a view schematically showing an end face of a honeycomb formed article being immersed in the slurry applied on a bottom face of the storage portion shown in Fig. 22.

[Reference Numerals]

1: slurry ejection apparatus, 2: container portion, 3: thrust-imparting portion, 4: nozzle portion, 8: longitudinal direction of ejection port, 9: width direction of ejection port, 10: slurry, 11: feed port, 12: ejection port, 13: buffer portion, 14: tip portion, 20: discharge port, 21: slurry application apparatus, 22: bottom face, 23: side wall, 24: storage portion, 25: retentive member, 26: wall portion, 30: interface of slurry, 31: start side, 32: end side, 40: lower face, 51: honeycomb formed article, 56: end face, 61: monoaxial eccentric screw pump, 62: rotor, 63: stator, 64: axis of stator, 65: discharge end portion, 66: axis of discharge end portion

Description of Preferred Embodiment

Hereinbelow, an embodiment of the present invention will be described with referring to drawings. The present invention is by no means limited to the following embodiment, and changes, modifications, and improvements may be made as long as they do not deviate from the scope of the present invention.
1. Slurry ejection apparatus:

1-1. Basic configuration of a slurry ejection apparatus of the present invention:
1. 1-1-1. Outline of a slurry ejection apparatus of the present invention:
  - A slurry ejection apparatus of the present invention ejects slurry from the slit-shaped ejection port of a nozzle portion. Fig. 1 is a vertical cross-sectional view of an embodiment of a slurry ejection apparatus of the present invention. Regarding the thrust-imparting portion 3 disposed inside the container portion 2, not a cross section, but a side face thereof is shown. A slurry ejection apparatus 1 of the present invention is provided with the container portion 2, thrust-imparting portion 3, and nozzle portion 4. The slurry 10 flows from the container portion 2 to the nozzle portion 4 in the flow passage inside the slurry ejection apparatus 1 and is ejected outside from the nozzle portion 4.

In the present specification, the "flow passage" means a cylindrical or tubular member forming a space where the slurry 10 flows inside the slurry ejection apparatus 1. In the present specification, the "flow passage cross section" means a cross section perpendicular to the flow direction of the slurry 10 among the cross sections of the internal space where the slurry 10 flows of the container portion 2 and the nozzle portion 4.
The "slurry" here contains at least a ceramic powder and a dispersion solvent, and the composition can be selected in accordance with the purpose of use. The slurry can be prepared by, for example, kneading a mixture of a ceramic powder and a dispersion powder for ceramic. There is no particular limitation on the kind of the ceramic powder, and examples of the ceramic power include a silicon carbide powder and a cordierite powder.
The aforementioned slurry has a viscosity of preferably 50 to 900 dPa·s, particularly preferably 100 to 500 dPa·s. When the viscosity of the slurry is below 50 dPa·s, since the flowability of the slurry is too high, the slurry involuntarily flows regardless of the thrust-imparting portion. For example, when the ejection port 12 faces downward as in Fig. 1, the slurry may flow out under its own weight without being retained in the nozzle. On the other hand, when the viscosity is above 900 dPa·s, since the slurry has low flowability, it may be impossible to allow the slurry to reach a point having a predetermined depth upon filling the slurry into the cells. In addition, a gap is prone to be caused because of insufficient filling into every part in the cells, and thereby an incomplete plugged portion may be formed.
1-1-2. Outline of container portion:

The container portion 2 contains the slurry 10 therein and is provided with a discharge port 20 for discharging the slurry 10. As long as this configuration is fulfilled, the container portion 2 can have a configuration in accordance with configurations of the thrust-imparting portion 3 and the nozzle portion 4, properties of the slurry 10, usage of the slurry ejection apparatus 1, and the like.

1-1-3. Outline of thrust-imparting portion:

The thrust-imparting portion 3 is disposed in the container portion 2. In Fig. 1, a monoaxial eccentric screw pump 61 is shown as the thrust-imparting portion 3. Incidentally, detailed description of the monoaxial eccentric screw pump will be given later. The thrust-imparting portion 3 may be any member as long as it extrudes the slurry 10 in the container portion 2 toward the discharge port 20. The thrust-imparting portion 3 may be a member which a person of ordinary skill in the art belonging to the technical field of the present invention generally uses, such as a cylinder and a pump which are driven by hydraulic pressure or air pressure besides the monoaxial eccentric screw pump 61 shown in Fig. 1.

1-1-4. Outline of nozzle portion:

Fig. 2 is a perspective view of the nozzle portion 4 of a slurry ejection apparatus 1 shown in Fig. 1 when seen from the ejection port 12 side. Fig. 3 is a plan view of the nozzle portion 4 shown in Fig. 2 when seen from the ejection port 12 side. The nozzle portion 4 is provided with the slit-shaped ejection port 12.

The "slit-shaped" here means that the length in the longitudinal direction 8 of the ejection port 12 is sufficiently larger than the length in the width direction perpendicular to the length in the longitudinal direction. In the nozzle portion 4 of a slurry ejection apparatus 1 of the present invention, an ejection port 12 where the percentage of the maximum length in the width direction 9 with respect to the length in the longitudinal direction 8 of the ejection port 12 is 20% or less is determined as a slit-shaped ejection port 12. It is further preferable that the percentage of the maximum length in the width direction 9 with respect to the length in the longitudinal direction 8 of the ejection port 12 is 10% or less.
As shown in Fig. 3, in the present specification, the longitudinal direction means the longitudinal direction 8 of the ejection port 12. The width direction 9 means the direction perpendicular to the longitudinal direction 8 and direction of the width of the ejection port 12. Incidentally, when the word, longitudinal direction 8, is used upon describing the container portion 2 or the thrust-imparting portion 3, the case that the nozzle portion 4 is mounted on the ejection apparatus 1 is supposed, and the position and the direction regarding the container 2 and the thrust-imparting portion 3 are shown on the basis of the longitudinal direction 8 of the ejection port 12 of the nozzle portion 4 (see the longitudinal direction 8 in Fig. 1).

1-1-4-1. Feed port:

Fig. 4A is a cross-sectional view taken along A-A' shown in Fig. 2, that is, a vertical cross-sectional view of the nozzle portion 4 along the longitudinal direction 8 of the ejection port 12. Fig. 4B is a cross-sectional view taken along B-B' shown in Fig. 2, that is, a vertical cross-sectional view of the nozzle portion 4 along the width direction 9 of the ejection port 12. The nozzle portion 4 is provided with a feed port 11. The feed port 11 communicates with the discharge port 20. Therefore, the slurry 10 which has flowed to the discharge port 20 through the container portion 2 flows into the nozzle portion 4 from the feed port 11 (see Fig. 1).
The shape of the feed port 11 can be determined arbitrarily and does not have to the same slit shape as in the ejection port 12. For example, it is preferable that the shape of the feed port 11 has a widely opened shape like the discharge port 20 so that the slurry 10 can easily flow into the nozzle portion 4.

1-1-4-2. Buffer portion:

In the nozzle portion 4 is formed a flow passage having a large cross-sectional area. A buffer portion 13 is provided, and a configuration capable of storing slurry in the buffer portion 13 may be employed. In each of the nozzle portions 4 shown in Figs. 4A and 4B, the feed port 11 is widely opened, and the buffer portion 13 is formed in such a manner that the area of the flow passage cross section in the vicinity of the feed port 11 is the same as the opening area of the feed port 11. By providing the buffer portion 13, when the slurry 10 flows in from the feed port 11 with a bias in the flow amount and/or the flow velocity, the bias can be relaxed. The configuration of the buffer portion 13 can be determined in accordance with the state of inflow of the slurry 10 from the feed port 11 and properties of the slurry 10. However, since the effect decreases as the slurry viscosity is lowered, a buffer layer is positioned subsidiarily.
The buffer portion 13 is formed in such a manner that one of the end portions functions as the feed port 11. The buffer portion 13 does not have to have a configuration as shown in Figs. 4A or 4B. For example, it is possible that, after the area of a flow passage cross section in the vicinity of the feed port 11 is made small, the area of a flow passage cross section on the ejection port 12 side is made large to form the buffer portion 13.
The buffer portion 13 can be formed also in such a manner that the area of the flow passage cross section is gradually reduced toward the ejection port 12 side.

1-1-4-3. Ejection port of nozzle portion:

Fig. 5 is an enlarged view of the ejection port 12 in the plan view of the nozzle portion 4 of Fig. 3. The ejection port 12 of the nozzle portion 4 provided on a slurry ejection apparatus 1 can have a configuration capable of ejecting the slurry 10 at an almost uniform flow amount along the longitudinal direction 8 even in the case that the slurry 10 flows to the ejection port 12 with variance in the flow velocity in the longitudinal direction 8. Specifically, the ejection port 12 is formed with a fixed length in the width direction 9 in each position in the longitudinal direction 8 so that the slurry 10 ejection amount per unit time in each position in the longitudinal direction 8 becomes almost the same.
Incidentally, in the case that the slurry 10 flows to the ejection port 12 without variance in the flow velocity along the longitudinal direction or that it is not necessary to require strict uniformity, the shape of the ejectionport 12 maybe a simple rectangle (oblong figure) shown in Fig. 6. This case is also within the range of the aforementioned technical concept because the length in the width direction 9 of the ejection port 12 is fixed so that the slurry 10 ejection amount per unit time in each position in the longitudinal direction 8 becomes almost the same.
Fig. 7 is a view schematically showing the relation between the lengths W_a and W_b in the width direction 9 of the ejection port 12 and the slurry 10 ejection amounts per unit time (hereinbelow referred to as "unit ejection amounts") V_a and V_b in the positions a and b, respectively, along the longitudinal direction 8. Fig. 7 shows the slurry 10 being ejected for a predetermined unit time from the ejection port 12 drawn on the top side of Fig. 7 toward the horizontal bottom face 22 drawn on the lower side.
In the ejection port 12 shown in Fig. 7, the flowvelocity (v_a) of the slurry 10 is high in the position a in the center in the longitudinal direction 8, and the flow velocity (v_b) of the slurry 10 is low in the position b on the end side in the longitudinal direction 8. In order to make the unit ejection amount V_a of the slurry 10 and the unit ejection amount V_b of the slurry 10 almost the same, the length W_a in the width direction 9 of the ejection port 12 in the position a is made small, and the length 4V_b in the width direction 9 of the ejection port 12 in the position b is made large. As a result, the unit ejection amount V_a in the position a and the unit ejection amount V_b in the position b are almost the same, and thereby the height T_a of the slurry 10 ejected from the position a and the height T_b of the slurry 10 ejected from the position b are almost the same on the bottom face 22. That is, a flat interface 30 of the slurry 10 appears on the bottom face 22.
Fig. 8 schematically shows a case that the slurry 10 is ejected from the ejection port 12 having a simple rectangular shape when the flow velocity of the slurry 10 has a bias in the same state as the case of Fig. 7 as an example in contrast to the case shown in Fig. 7. In such a case, the unit ejection amount V_a of the slurry 10 in the position a is large, and the unit ejection amount V_b of the slurry 10 in the position b is small. Therefore, in the bottom face 22, the height T_a of the slurry 10 ejected from the position a is larger than the height T_b of the slurry 10 ejected from the position b, and the interface 30 of the slurry 10 has unevenness with the center in the longitudinal direction 8 being higher than a portion on the end side.
Incidentally, as long as the length in the width direction 9 of the ejection port 12 fulfills the aforementioned requirement, the shape of the ejection port 12 shown in Figs. 5 and 7 may be changed to the shape shown in Fig. 9A.
As further description with referring to Fig. 7, for example, the unit ejection amount V_a in the position a is def ined as the ejection amount of the slurry passing per unit time though the flow passage cross section S_a in a gap g set so as to have a predetermined length in the longitudinal direction 8 in the position a. That is, the unit ejection amount V_a is shown by a value obtained by multiplying the area of the flow passage cross section S_a in the gap by the flow velocity v_a of the slurry 10 flowing the cross section S_a. The length of the gap g is obtained in accordance with the degree of uniformity of the unit ejection amount obtained for each actual embodiment.
In the case that the velocity of the slurry 10 continuously changes along the longitudinal direction 8, when the uniformity of the unit ejection amount of the slurry 10 along the longitudinal direction 8 is strict, continuous change of also the length in the width direction 9 of the ejection port 12 as shown in Fig. 5 or 9A is good. In the same case, when a small error is allowed in the uniformity of the unit ejection amount of the slurry 10 along the longitudinal direction 8, as shown in Figs. 9B, 9C described later, and 9D, there may be employed a configuration where the length in the width direction 9 of the ejection port 12 is intermittently changed along the longitudinal direction 8. In the case that the error in the unit ejection amount is further allowed, a simple rectangle may be employed as shown in Fig. 6.
The uniformity of the depth of filling of the slurry 10 in the cells in the end portions of a honeycomb formed article depends on the flatness of the interface 30 the slurry 10 (filling of slurry in cells will be described later). When the slurry 10 is filled deeply in a certain cell, it can be understood that the interface 30 of the slurry 10 in the position where the cell is immersed is high, that is, the unit ejection amount of the slurry 10 is large. in this case, based on the depth of filling of the slurry 10, the length in the width direction 9 of the ejection port 12 in the corresponding position can be modified to be small.

1-2. Embodiment where the slurry is allowed to flow continuously in the longitudinal direction to the ejection port:

In order to take advantage of the aforementioned function effect by the configuration of the nozzle portion 4, it is preferable to allow the nozzle portion 4 to have a configuration where the slurry is allowed to flow to the ejection port 12 so that the difference in flow velocity of the slurry 10 in each position in the longitudinal direction 8 is reduced. Therefore, it is preferable that the nozzle portion 4 has a flow passage having a slit-shaped flow passage cross section formed up to the ejection port 12 and is provided with a tip portion 14 which send the slurry 10 to the ejection port 12 continuously in the longitudinal direction 8. Fig. 10 is a cross-sectional view taken along the C-C' shown in Fig. 2, i.e., a vertical cross-sectional view of the nozzle portion 4. The position of the C-C' cross section is shown in the vertical cross-sectional views of Figs. 4A and 4B.
In the nozzle portion 4 of the slurry ejection apparatus 1 shown in Fig. 11, the tip portion 14 is formed to allow the slurry to flow to the ejection port 12 continuously in the longitudinal direction 8. Fig. 13A shows a distribution of the flow velocity of the slurry 10 along the longitudinal direction 8 at the upstream end of the tip portion 14 shown by the position U in Fig. 11. Fig. 13B shows a distribution of the flow velocity of the slurry 10 along the longitudinal direction 8 at the ejection port 12 shown by the position L in Fig. 11.
As shown in Fig. 13A, at the position U of the tip portion 14, variance in flow velocity of the slurry 10 is caused between the ends X1 and X2 in the longitudinal direction 8.
In the middle of the flow from the position U to the ejection port 12 (position L), the flow of the slurry 10 having high velocity becomes slow by the resistance of the flow of the slurry 10 having low flow velocity. Inversely, the flow of the slurry 10 having low flow velocity becomes fast by being pulled by the flow of the slurry 10 having high velocity. Therefore, as shown in Fig. 13B, in the ejection port 12, the slurry 10 has a relaxed variance in flow velocity of the slurry 10 along the longitudinal direction 8.
As is imagined from the above description, the length of the flow passage of the tip portion 14 may be adjusted in accordance with variance in flow velocity of the slurry 10 along the longitudinal direction 8. When the variance in the flow velocity of the slurry 10 along the longitudinal direction 8 is large, by increasing the flow passage length of the tip portion 14, the variance in the flow velocity of the slurry 10 can effectively be relaxed.
When the tip portion 14 having such a configuration is provided on the nozzle portion 4, since the slurry 10 can be ejected with small variance in the flow velocity along the longitudinal direction 8, the length in the width direction 9 of the ejection port 12 described earlier with referring to Fig. 7 can be set more precisely. In particular, as shown in Fig. 1, in the case of providing a monoaxial eccentric screw pump 61 as the thrust-imparting portion 3, since the place where the slurry 10 flow amount is high and the place where the slurry 10 flow amount is low change with the passage of time along the longitudinal direction 8, it is preferable that the tip portion 14 having such a configuration is provided on the nozzle portion 4 (the details will be described later).
Incidentally, as long as the aforementioned relaxing function of the slurry 10 is exhibited, the tip portion 14 may have a configuration where the continuity of the slurry along the longitudinal direction 8 is temporarily segmentalized in the middle of the flow passage.
In the nozzle portion 4 of the slurry ejection apparatus 1 shown in Fig. 12 as a configuration in contrast, the tip portion 14 is branched into a comb shape and is not formed to allow the slurry 10 to continuously flow to the ejection port 12 over the longitudinal direction 8. When the flow velocity of the slurry 10 at the position U of the tip portion 14 in Fig. 12 is the same as that at the position U of Fig. 11, since relaxation of the flow velocity of the slurry 10 like the tip portion 14 in Fig. 11 is not conducted, as shown in Fig. 13C, the slurry is ejected from the ejection port 12 with the variance in the flow velocity of the slurry along the longitudinal direction 8 being kept large.
1-3. Embodiment where the slurry flows into the nozzle portion with biases in the flow amount and the flow velocity:
In a slurry ejection apparatus 1 of the present invention, there can effectively be employed a configuration where the slurry 10 is extruded with the thrust-imparting portion 3 causing biases in the flow amount and the flow velocity.
As a thrust-imparting portion 3 having such a configuration, there is a portion where the discharge port 20 is partially covered to allow the slurry 10 to flow into the nozzle portion 4 by increasing the average flow amount of the slurry in the center in the longitudinal direction 8 and decreasing the average f low amount of the slurry 10 at the ends in the longitudinal direction 8 with changing the position and the area where the discharge port 20 is covered with the passage of time.
For example, when the slurry 10 flows into the nozzle portion 4 in the state that the average flow velocity of the slurry 10 is high in the center in the longitudinal direction 8 and low on the end sides, it is preferable that, after relaxing variance in the flow amount and the flow velocity of the slurry with the passage of time by providing the tip portion 14 for allowing the slurry to continuously flow to the ejection port 12 over the longitudinal direction 8 as described above, the length in the width direction 9 is formed to be small in the center in the longitudinal direction 8 and maximized at the ends in the longitudinal direction or in the vicinity of the ends in the longitudinal direction 8 in order to relax the steady bias of the average flow velocity along the longitudinal direction 8. Alternatively, when the slurry 10 flows in the nozzle portion 4 in the state that the average flow amount of the slurry 10 is large in the center in the longitudinal direction 8 and small on the end sides, it is preferable that the ejection port 12 of the nozzle portion 4 is formed in such a manner that the length in the width direction 9 is small in the center in the longitudinal direction 8 and maximized at the ends in the longitudinal direction 8 or in the vicinity of the ends in the longitudinal direction 8. Examples of the ejection port 12 of a nozzle portion 4 having such a configuration are shown in Figs. 9C and 9D.
When slurry flows through the tip portion 14, the slurry is subjected to resistance from the flow passage wall face on the end side in the longitudinal direction 8 of the tip portion 14. As described above, in the ejection port 12 of the nozzle portion 4, when the length in the width direction 9 is formed to be the maximum at the ends in the longitudinal direction 8 or in the vicinity of the ends in the longitudinal direction 8, the ejection amount along the longitudinal direction 8 easily becomes more uniform.
Further, as shown in Figs. 9A and 9B, the nozzle portion 4 can have a configuration where the length in the width direction 9 of the ejection port 12 is the smallest in the center in the longitudinal direction 8 and increases toward the ends in the longitudinal direction 8.
1-4. Embodiment where monoaxial eccentric screw pump is provided as the thrust-imparting portion:
Since the monoaxial eccentric screw pump 61 can extrude slurry continuously and quantitatively without pulsation, it is suitable as the thrust-imparting portion 3 of a slurry ejection apparatus 1 of the present invention. Fig. 14 shows a vertical cross section of the container portion 2 having the monoaxial eccentric screw pump 61 as the thrust-imparting portion 3 therein. When the monoaxial eccentric screw pump 61 is used as the thrust-imparting portion 3, screw shaped rotor 62 and stator 63 are disposed inside the container portion 2.
Fig. 15 shows a horizontal cross section along A-A' in Fig. 14 and continuously shows a reciprocating motion of the discharge end portion 65 in the rotor 62. The stator 63 has an oblong space cross section. The rotor 62 has a circular cross section and fits into the oblong space of the stator 63. The discharge end portion 65 of the rotor 62 reciprocates along the longitudinal direction 8 when viewed from a horizontal cross section of the discharge port 20. On the other hand, the flow of the slurry 10 has a bias along the longitudinal direction 8. By this mechanism, the slurry 10 is discharged from the discharge port 20 with the bias of the flow being fluctuated. Specifically, in a container portion 2 where the monoaxial eccentric screw pump 61 is disposed, the discharge port 20 is partially covered by the discharge end portion 65, and the slurry 10 flows into the nozzle portion 4 with changing the position and the area where the discharge port 20 is covered by the discharge end portion 65 with the passage of time so that the average flow amount of the slurry 10 is increased in the center of the longitudinal direction 8 and that the average flow amount of the slurry 10 is decreased at the ends in the longitudinal direction 8.
with referring to Figs. 14 and 15, in the case that the direction of the reciprocating motion of the discharge end portion 65 of the rotor 62 is matched to the longitudinal direction 8 of the ejection port 12 and that the center of the ejection port 12 is matched to the extension of the axis 64 of the stator 63, the slurry 10 flows into the nozzle portion 4 along the longitudinal direction 8 in the state that the average flow amount in the central portion is large and that the average flow amount on the end sides is small. In this case, the velocity of the slurry 10 is high in the center of the ejection port 12 and low on the end sides in the longitudinal direction 8. Therefore, when the length in the width direction 9 of the ejection port 12 is the smallest in the center in the longitudinal direction 8 and the maximum at the ends in the longitudinal direction 8 and in the vicinity of the ends in the longitudinal direction 8 (see Figs. 5 and 9A to 9D), the unit ejection amount of the slurry 10 becomes almost uniform along the longitudinal direction 8. Since this tendency becomes more remarkable as the percentage of the length in the axial direction 9 with respect to the length in the longitudinal direction 8 of the ejection port 12 increases, in the case that the uniformity of the unit ejection amount of the slurry 10 along the longitudinal direction 8 is strict, as shown in Fig. 5 or Fig. 9A, a configuration where the length in the width direction 9 of the ejection port 12 is also continuously changed along the longitudinal direction 8 is more preferable.
It is good to provide the slurry ejection apparatus 1 of the present invention described above on the slurry application apparatus 21 for applying the slurry 10 in a plane state to obtain a flat interface 30.

2. Slurry application apparatus:

2-1. Basic configuration of slurry application apparatus of the present invention:

Next, a slurry application apparatus completed by the present inventors (hereinbelow referred to as a "slurry application apparatus of the present invention") will be described. Fig. 16 schematically shows a slurry application apparatus 21 of the present invention applying the slurry 10 on the bottom face 22. Fig. 17 is a view of the application of the slurry 10 shown in Fig. 16 when seen from the top side of the bottom face 22.
A slurry application apparatus 21 of the present invention has the aforementioned slurry ejection apparatus 1 of the present invention and a flat bottom face 22 and is provided with the storage portion 24 for receiving the slurry 10 ejected from the slurry ejection apparatus 1.
In the slurry application apparatus 21 of the present invention, the nozzle portion 4 of the slurry ejection apparatus 1 is located over the bottom face 22, and the ejection port 12 of the nozzle portion 4 faces the bottom face 22.
In a slurry application apparatus 21 of the present invention, at least the nozzle portion 4 moves at a relatively fixed velocity with respect to the bottom face 22 with ejecting the slurry 10 from the ejection port 12 of the slurry ejection apparatus 1 toward the bottom face 22.
In a slurry application apparatus 21 of the present invention, it is preferable that the slurry ejection apparatus 1 is provided in such a manner that the nozzle portion 4 moves lest the slurry 10 newly applied should overlap the slurry 10 already applied on the bottom face 22. By this configuration, the slurry 10 is applied in a plane state on the bottom face 22, and the interface 30 of the applied slurry 10 becomes flat. In addition, the moving velocity of the nozzle portion 4 can suitably be selected so as to apply the slurry 10 on the bottom face 22 with a desired height of the slurry 10 with viscosity of slurry 10, length of the ejection port 12 in the width direction 9, and the like in mind.

2-2. Embodimentprovidedwithplate-shaped storage portion having side wall:

Fig. 18 shows an embodiment of a slurry application apparatus 21 of the present invention. The storage portion 24 of the slurry application apparatus 21 shown in Fig. 19 has a plate shape where the side walls 23 surround the periphery of the bottom face 22. By providing the side walls 23, the slurry 10 applied is inhibited from flowing on the bottom face 22. When the flow of the slurry 10 is inhibited, since change of the shape of the interface 30 of the slurry 10 is also inhibited, the interface 30 of the slurry 10 is kept flat.
The storage portion 24 having such a configuration preferably has a plate shape where the bottom face 22 is surrounded by the side walls 23 forming a rectangle and having a start side and an end side 32 facing each other and having a length larger than the length in the longitudinal direction 8 of the discharge port 12 (see Fig. 19). When the storage portion 24 is provided, it is preferable that, in the slurry ejection apparatus 1, the nozzle portion 4 is provided so as to move at a fixed velocity from the inside of the start side 31 toward the inside of the end side 32 with ejecting the slurry 10. This configuration more securely inhibits the aforementioned flow of the slurry 10.

2-3. Embodiment provided with retentive member:

A slurry application apparatus 21 of the present invention can be provided with a retentive member 25 described below in order to inhibit the flow of the slurry 10 applied on the bottom face 22 and keep the flat shape of the interface 30 of the slurry 10. Fig. 20 shows a configuration of the retentive member 20, and the upper view is a front view, while the lower view is a vertical cross-sectional view taken along the A-A'. The retentive member 25 has a ring-shaped wall portion 26 surrounding the slurry 10 applied on the bottom face 22. Further, the lower face 40 of the wall portion 26 can adhere to the bottom face 22. In a slurry application apparatus 21 of this embodiment, Figs. 21 and 22 show the retentive member 25 inhibiting the flow of the slurry 10. Fig. 21 is a plan view seen from atop the bottom face 22. Fig. 22 is a vertical cross-sectional view taken along the A-A' of Fig. 21.
In this slurry application apparatus 21, in the first place, the slurry 10 is applied in a plane state in a range wider than the region surrounded by the ring of the wall portion 26 on the bottom face 22 (see Fig. 17). Next, the retentive member 25 is pressed from above the slurry 10 so that the slurry 10 applied on the bottom face 22 fits in the ring of the wall portion 26 to allow the lower face 40 of the wall portion 26 adhere to the bottom face 22. By the retentive member 25, the flow of the slurry 10 applied on the bottom face 22 is inhibited, and the interface 30 of the slurry 10 is maintained to have the initial flat shape.
In this embodiment, the ring of the wall portion 26 may have any shape such as a circle, an ellipse, a quadrangle, and a triangle. For example, when it is used for filling the slurry 10 from an end face of a honeycomb formed article 51, the shape of the ring of the wall portion 26 can be determined arbitrarily according to the shape and size of the end face of the honeycomb formed article. By the use of the retentive member 25, it is possible to apply the slurry with a fixed thickness by the common setting for honeycomb formed articles having close end face sizes to some extent, and productivity is improved because of less adjustment items and less adjustment time upon changing the kind.

3. Method for manufacturing a plugged honeycomb structure:

The aforementioned slurry application apparatus 21 of the present invention may be used in a step for filling the slurry 10 at an end portion of each cell of a honeycomb formed article 51 upon manufacturing a plugged honeycomb structure. In a slurry application apparatus 21 of the present invention, the slurry 10 can be applied in a plane state in such a manner that the slurry 10 has a flat interface 30 as shown in Figs. 7 and 22. Next, as shown in Fig. 23, the end face 56 of the honeycomb formed article 51 is immersed in the slurry 10 in such a manner that the end face 56 where cells are open of the honeycomb formed article 51 is matched to the flat interface 30 of the slurry 10 to fill the slurry 10 in the cells with uniform depth.
The method for filling the slurry 10 into an end portion of each cell of the honeycomb structure 51 may be a conventionally known method which a person of ordinary skill in the art can employ. An example is the method described in JP-A-2001-300922 .

Example

The present invention will be described in more detail on the basis of Examples. However, the present invention is by no means limited to these Examples.
4. Evaluation test employing depth of filling of slurry into end portions of honeycomb formed article as the index:
In the present evaluation test, there were manufactured a slurry application apparatus 21 provided with a slurry ejection apparatus 1 belonging to the present invention and a slurry application apparatus 21 provided with a slurry ejection apparatus 1 not belonging to the present invention. The slurry 10 was applied in a plane state on the bottom face 22 by the use of these slurry application apparatuses 21, and the slurry 10 was filled into the end portions of the cells of the honeycomb formed article 51 to check variance in depth of filling of the slurry 10 in a plurality of cells arbitrarily selected.

4-1. Slurry ejection apparatus:

In the slurry ejection apparatuses 1, the container portion 2 had a circular cylindrical shape, and the same monoaxial eccentric screw pump was used as the thrust-imparting portion 3 (see Fig. 1). There was used a buffer portion 13 of the nozzle portion 4 constituted of a cylindrical columnar-shaped flow passage having a diameter of 37 mm and formed up to the length of 3 mm from the feed port 11 toward the tip portion 14 side. The length of the tip portion 14 was 25.3 mm, and the length in the longitudinal direction 8 of the ejection port 12 was 36 mm. Examples 1 to 4 and Comparative Example 1 were determined depending on the shapes of the tip portion 14 and the ejection portion 12.

(Example 1 to 4)

The nozzle portion 4 of Examples 1 to 4 had a shape where the ejection port 12 as shown in Figs. 3 and 5 is slit shaped with the length in the width direction 9 of the ejection port 12 being the smallest in the center in the longitudinal direction 8 and continuously increasing toward both the ends. The shapes of the tip portion 14 and the ejection portion 12 of the nozzle portion 4 of each of Examples 1 to 4 are shown in Table 1.

Table 1

	Shape of tip portion and ejection port	Length in width direction of ejection port		Kind of slurry	Relative variance in plugging depth [%]
	Shape of tip portion and ejection port	End of ejection port [mm]	Center of ejection port [mm]	Kind of slurry	Relative variance in plugging depth [%]
Example 1	Slit	2.4	1.2	A	73%
				B	76%
				C	91%
Example 2	Slit	2.4	1.8	B	84%
Example 2	Slit	2.4	1.8	C	91%
Example 3	Slit	2.0	1.0	B	81%
Example 3	Slit	2.0	1.0	C	92%
Example 4	Slit	1.7	1.7	B	90%
Example 4	Slit	1.7	1.7	C	93%
Comp. Ex. 1	Comb shape	1.7	1.7	A	100%
				B	100%
				C	100%

(Example 1)

In the nozzle portion 4 of Comparative Example 1, as shown in Fig. 12, the tip portion 14 was formed to have a comb shape where circular cylindrical pipes are arranged in parallel with one another with the ejection port 12 being formed at the tip of each of the circular cylindrical pipes (Table 1).

4-2. Slurry application apparatus:

The slurry application apparatus 21 was provided with a slurry ejection apparatus 1 of one of Examples 1 to 4 and Comparative Example 1 and a plate-shaped storage portion 24 having a rectangular bottom face 22 having a longer side of 38 mm and a shorter side of 38 mm and side walls 23 surrounding the bottom face 22 (see Figs. 18 and 19). Hereinbelow, the slurry application apparatuses 21 each provided with one of the slurry ejection apparatuses 1 of Examples 1 to 4 and Comparative Example 1 were the slurry application apparatus 21 of Examples 1 to 4 or Comparative Example 1.
In addition, all of the moving velocity of the nozzle portion 4 upon ejection of slurry was 13.5 mm/sec.

4-3. Viscosity of slurry:

The slurry 10 having the following three kinds of viscosity was prepared. The viscosity of the slurry A was 176 dPa·s, the viscosity of the slurry B was 295 dPa·s, and the viscosity of the slurry C was 467 dPa· s. Here, the "viscosity of the slurry" was measured with a rotary viscometer. As the viscometer, there was used TVB-10H, rotor H7 produced by Toki Sangyo Co., Ltd. , and the measurement values were taken when 5 minutes had passed after the rotation of the rotor started with a rotation velocity of 30 rpm as the measurement conditions.

4-4. Filling of slurry of honeycomb formed article:

Regarding the slurry application apparatus 21 of Examples 1 to 4 and Comparative Example 1, the slurry 10 was applied in a plane state with the combinations shown in Table 1, and an end portion of a honeycomb formed article 51 was immersed in the slurry for filling of the slurry 10. The honeycomb formed article 51 was of silicon carbide and had a length of 203 mm (8 inches), an outer diameter of the end faces and a cross section perpendicular to the cell extension direction of a square of 37.5 mm × 37.5 mm, and a cell density in a cross section perpendicular to the cell extension direction of 46.5 cells/cm² (300 cells/inch²), and a partition wall thickness of about 0.3 mm.
Filling of the slurry 10 was performed in the same conditions in all the tests, and the average filling depth of the slurry 10 was 6 mm. The kinds of the slurry used in Examples 1 to 4 and Comparative Example 1 were shown in Table 1.

4-5. Evaluation of degree of variance in filling depth of slurry:

The evaluation of the degree of variance in filling depth of slurry was performed independently regarding each of the slurries A to C having a difference in the viscosity. Regarding the evaluation on the slurry A, the variance in filling depth of the slurry 10 when the slurry 10 applied by the slurry application apparatus 21 of each of the Examples 1 to 4 was filled in cells in an end portion of the honeycomb formed article 51 with respect to the variance in filling depth of the slurry 10 when the slurry 10 applied by the slurry application apparatus 21 of the Comparative Example 1 was filled in cells in an end portion of the honeycomb formed article 51 was obtained in percentage (%), and it was expressed by "relative variance in plugging depth". The same was applied to the evaluations on the slurries B and C. The variance in the filling depth of the slurry 10 was defined as a standard deviation calculated from the measurement values obtained by arbitrarily choosing 13 cells apart from one another at almost the same interval on the end face of the honeycomb formed article 51 twice independently and measuring the filling depth of the slurry 10 in a total of 26 cells.
Regarding Examples 1 to 4 and Comparative Example 1, the "relative variances of plugging depth" when the slurries A to C were filled in the honeycomb formed articles are shown in Table 1.
From the results, it was found out that, in Examples 1 to 4, the slurry 10 was applied to have a flat interface in comparison with Comparative Example 1.
The present invention can be used as a slurry ejection apparatus, a slurry application apparatus, and a method for manufacturing a plugged honeycomb structure for applying slurry functioning as a material for plugging portions of a plugged honeycomb structure.

Claims

A slurry ejection apparatus (1) comprising:
a container portion (2) containing slurry (10) therein and having a discharge port (20) for discharging the slurry (10),

a thrust-imparting portion (3) disposed in the container portion (2) and extending the slurry (10) toward the discharge port (20), and

a nozzle portion (4) provided with a feed port (11) communicating with the discharge port (20) and allowing the slurry (10) to flow into the nozzle portion (4) and a slit-shaped ejection port (12) for ejecting the slurry (10) flowed into the nozzle portion (4); characterised in that

the ejection port (12) is formed with a fixed length in the width direction (9) of the ejection port (12) in each position in a longitudinal direction of the discharge port (20) to almost uniformalize an ejection amount per unit time of the slurry (10) in each position in the longitudinal direction (8) of the ejection port (12).
The slurry ejection apparatus (1) according to Claim 1, wherein
the nozzle portion (4) is provided with a tip portion (14) to decrease a difference in a flow velocity of the slurry (10) in each position in the longitudinal direction (8) in the ejection port (12), and
in the tip portion (14), a flow passage having a slit-shaped cross section is formed to the ejection port (12) to allow the slurry (10) to flow continuously in the longitudinal direction (8).
The slurry ejection apparatus (1) according to Claim 1 or 2, wherein the thrust-imparting portion (3) allows the slurry (10) to flow into the nozzle portion (4) with generating a bias in the flow amount and the flow velocity.
The slurry ejection apparatus (1) according to any one of Claims 1 to 3, wherein
the thrust-imparting portion (3) allows the slurry (10) to flow into the nozzle portion (4) with increasing an average flow amount in the center of the longitudinal direction (8) and decreasing the average flow amount on end sides in the longitudinal direction (8), while the discharge port (20) is partially covered with changing the position and area where the discharge port (20) is covered with the passage of time, and
the length in the width direction (9) of the ejection port (12) of the nozzle portion (4) is the smallest in the center in the longitudinal direction (8) and the largest in the ends or in the vicinity of the ends.
The slurry ejection apparatus (1) according to Claim 4, wherein
the thrust-imparting portion (3) is a rotary capacity type monoaxial eccentric screw pump (61) which continuously extrudes the slurry (10) and which allows the slurry (10) to flow into the nozzle portion (4) with increasing the average flow amount of the slurry (10) in the center in the longitudinal direction (8) and decreasing the average flow amount of the slurry (10) on the end sides in the longitudinal direction (8), and
the length in the width direction (9) of the ejection port (12) of the nozzle portion (4) is the smallest in the center in the longitudinal direction (8) and the largest in the ends or in the vicinity of the ends.
The slurry ejection apparatus (1) according to any one of Claims 1 to 5,
the length in the width direction (9) of the ejection port (12) of the nozzle portion (4) is the smallest in the center in the longitudinal direction (8) and the largest in the ends or in the vicinity of the ends.
A slurry application apparatus (21) comprising:
a slurry ejection apparatus (1) according to any one of Claims 1 to 6, and

a storage portion (24) having a flat bottom face (22) and receiving the slurry (10) ejected from the slurry ejection apparatus (1); wherein

the nozzle portion (4) is provided over the bottom face (22), the ejection port (12) of the nozzle portion (4) faces the bottom face (22), and the nozzle portion (4) is movable at a fixed speed relatively with respect to the bottom face (22) with ejecting the slurry (10) from the ejection port (12) to apply the slurry (10) in a plane state on the bottom face (22).
The slurry application apparatus (21) according to Claim 7, comprising a retentive member (25) for retaining a shape of an interface (30) of the slurry (10) while suppressing a flow of the slurry (10) after the slurry (10) is applied on the bottom face (22),
wherein the retentive member (25) is detachable from the bottom face (22) and has a ring-shaped wall portion (26) for surrounding the slurry (10) applied on the bottom face (22), and the wall portion (26) is provided with a lower face (40) to adhere to the bottom face (22).
A method for manufacturing a plugged honeycomb structure, comprising:
using a slurry application apparatus (21) according to Claim 7 or 8 to eject slurry (10) from the slurry ejection apparatus (1) of the slurry application apparatus (21) to the bottom face (22) of the storage portion (24) of the slurry application apparatus (21), and

after the slurry (10) is applied on the bottom face (22) in a plane state, immersing an end face (56) where cells are open of a honeycomb formed article (51) in the slurry (10) to fill the slurry (10) into the cells.