Background of the Invention
[0001] The present invention relates to a slurry ejection apparatus,aslurryapplication apparatus,and
a method for manufacturing a plugged honeycomb structure.
[0002] 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).
[0003] 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.
[0004] 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.
[0005] 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.
[0006] 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.
[0007] 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.
[0008] 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.
[0009] 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.
[0010] 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.
Summary of the Invention
[0011] 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.
[0012] 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.
[0013] [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.
[0014] [2] 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.
[0015] [3] 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.
[0016] [4] 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.
[0017] [5] 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.
[0018] [6] 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.
[0019] [7] 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, the nozzle portion moves 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.
[0020] [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.
[0021] [9] A method for manufacturing a plugged honeycomb structure, wherein a slurry application
apparatus in [7] or [8] is used, and the method has a step where, after the slurry
is applied on the bottom face in a plane state, an end face where cells are open of
a honeycomb formed article is immersed in the slurry to fill the slurry into the cells.
[0022] 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
[0023] [Fig. 1] Fig. 1 is a view schematically showing a cross section of an embodiment
of a slurry ejection apparatus of the present invention.
[0024] [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.
[0025] [Fig. 3] Fig. 3 is a plan view of the nozzle portion shown in Fig. 2 when seen from
the ejection port side.
[0026] [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.
[0027] [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.
[0028] [Fig. 5] Fig. 5 is an enlarged view showing the ejection port in the plan view of
Fig. 3.
[0029] [Fig. 6] Fig. 6 is an enlarged view showing a plan view of a rectangular ejection
port.
[0030] [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.
[0031] [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.
[0032] [Fig. 9A] Fig. 9A is an enlarged plan view of an ejection port of a nozzle portion.
[0033] [Fig. 9B] Fig. 9B is an enlarged plan view of an ejection port of a nozzle portion.
[0034] [Fig. 9C] Fig. 9C is an enlarged plan view of an ejection port of a nozzle portion.
[0035] [Fig. 9D] Fig. 9D is an enlarged plan view of an ejection port of a nozzle portion.
[0036] [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.
[0037] [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.
[0038] [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.
[0039] [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.
[0040] [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.
[0041] [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.
[0042] [Fig. 14] Fig . 14 isavertical cross section of a container portion provided with
an monoaxial eccentric screw pump therein as the thrust-imparting portion.
[0043] [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.
[0044] [Fig. 16] Fig. 16 is a view schematically showing a slurry application apparatus
of the present invention applying slurry.
[0045] [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.
[0046] [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.
[0047] [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.
[0048] [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.
[0049] [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.
[0050] [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.
[0051] [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]
[0052] 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
[0053] 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.
[0054] 1. Slurry ejection apparatus:
- 1-1. Basic configuration of a slurry ejection apparatus of the present invention:
- 1-1-1. Outline of a slurry application 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.
[0055] 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.
[0056] 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.
[0057] 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.
[0058] 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.
[0059] 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.
[0060] 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.
[0061] 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.
[0062] 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:
[0063] 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).
[0064] 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:
[0065] 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.
[0066] 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.
[0067] 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:
[0068] 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.
[0069] 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.
[0070] 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.
[0071] 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.
[0072] 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.
[0073] 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.
[0074] 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.
[0075] 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.
[0076] 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:
[0077] 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.
[0078] 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.
[0079] 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.
[0080] 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.
[0081] 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.
[0082] 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).
[0083] 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.
[0084] 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.
[0085] 1-3. Embodiment where the slurry flows into the nozzle portion with biases in the
flow amount and the flow velocity:
[0086] 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.
[0087] 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.
[0088] 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.
[0089] 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.
[0090] 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.
[0091] 1-4. Embodiment where monoaxial eccentric screw pump is provided as the thrust-imparting
portion:
[0092] 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.
[0093] 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.
[0094] 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.
[0095] 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:
[0096] 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.
[0097] 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.
[0098] 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.
[0099] 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.
[0100] 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:
[0101] 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.
[0102] 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:
[0103] 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.
[0104] 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.
[0105] 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:
[0106] 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.
[0107] 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
[0108] 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.
[0109] 4. Evaluation test employing depth of filling of slurry into end portions of honeycomb
formed article as the index:
[0110] 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:
[0111] 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)
[0112] 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.
[0113]
Table 1
|
Shape of tip portion and ejection port |
Length in width direction of ejection port |
Kind of slurry |
Relative variance in plugging depth [%] |
End of ejection port [mm] |
Center of ejection port [mm] |
Example 1 |
Slit |
2.4 |
1.2 |
A |
73% |
B |
76% |
C |
91% |
Example 2 |
Slit |
2.4 |
1.8 |
B |
84% |
C |
91% |
Example 3 |
Slit |
2.0 |
1.0 |
B |
81% |
C |
92% |
Example 4 |
Slit |
1.7 |
1.7 |
B |
90% |
C |
93% |
Comp. Ex. 1 |
Comb shape |
1.7 |
1.7 |
A |
100% |
B |
100% |
C |
100% |
(Example 1)
[0114] 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:
[0115] 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.
[0116] 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:
[0117] 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:
[0118] 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 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/cm
2 (300 cells/inch
2), and a partition wall thickness of about 0.3 mm.
[0119] 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:
[0120] 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.
[0121] 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.
[0122] 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.
[0123] 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.