DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim Rejections - 35 USC § 112(b)
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 2–7, 9–12, 15–16 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claims 2–3 are indefinite because the term “the intersections” lacks antecedent basis. Additionally, the term “the diameter t2” lacks antecedent basis because vacant intersection space does not inherently have a diameter.
Claims 4–7, 9–12, 15–16 are indefinite because they depend on claim 2 or claim 3.
Claim Rejections - 35 USC § 102(a)(1)
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
The claims are rejected as follows:
Claims 1 and 8 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Okumura et al., US 2006/0263573 A1 (“Okumura”).
Regarding claim 1:
Okumura discloses that a silicon carbide honeycomb filter (Okumura’s honeycomb structure 1, Fig. 1, [0023]) constituted by honeycomb segments (Okumura’s honeycomb segments 2, Fig. 2, [0023]) each comprising cell walls (Okumura’s partition walls 6, Fig. 1, [0024]) forming cells (Okumura’s cells 5, Fig. 1, [0023]) defining pluralities of flow paths (Okumura discloses as fluid channels, Fig. 1, [0023]) longitudinally extending between both end surfaces (Okumura’s left and end portions as best shown in Fig. 4),
plugs sealing (Okumura’s filling material 7, Fig. 2, [0024] end surfaces of said cells alternately in a checkerboard pattern (as shown in Fig. 2 of Okumura),
and an outer peripheral wall (Okumura’s outer peripheral surface of the bonding honeycomb segment article 10, where outer peripheral coating layer 4 locates, Fig. 1, [0023]), bonding material layers (Okumura’s bonding material layer 9, Fig. 1, [0024]) filling lattice gaps between said honeycomb segments for bonding them (Okumura Fig. 1, [0024]), and a skin layer (Okumura’s outer peripheral coating layer 4, Fig. 1, [0024]) enclosing the bonded honeycomb segments (see Okumura Fig. 1, [0024]),
said lattice gaps (as shown in Okumura Fig. 5, space between the partial bonding material layers 9, Fig. 5, [0027]) being provided with a bonding-material-free region extending in four directions from a center intersection to adjacent intersections (best shown in Okumura Fig. 2), wherein said center intersection is an intersection located at the center axis of said honeycomb filter (best shown in Okumura Fig. 2) or its nearby position among intersections of said lattice gaps.
Regarding claim 8:
Modified Okumura discloses that the silicon carbide honeycomb filter according to claim 1, wherein said outer peripheral wall of each honeycomb segment is thicker than said cell walls (Okumura discloses an example 1, where the partition wall thickness is 310 mu.m and an outer wall thickness is 1 mm, which is thicker than the cell walls, Okumura [0039]).
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
The claims are rejected as follows:
Claims 2–7 and 9–10 are rejected under 35 U.S.C. 103 as being unpatentable over Okumura in view of Shibata et al., US 2015/0033690 A1 (‘Shibata”).
Regarding claim 2:
Okumura discloses that a silicon carbide honeycomb filter (Okumura’s honeycomb structure 1, Fig. 1, [0023]) constituted by honeycomb segments (Okumura’s honeycomb segments 2, Fig. 2, [0023]) each comprising cell walls (Okumura’s partition walls 6, Fig. 1, [0024]) forming cells (Okumura’s cells 5, Fig. 1, [0023]) defining pluralities of flow paths (Okumura discloses as fluid channels, Fig. 1, [0023]) longitudinally extending between both end surfaces (Okumura’s left and end portions as best shown in Fig. 4),
plugs sealing (Okumura’s filling material 7, Fig. 2, [0024] end surfaces of said cells alternately in a checkerboard pattern (as shown in Fig. 2 of Okumura),
and an outer peripheral wall (Okumura’s outer peripheral surface of the bonding honeycomb segment article 10, where outer peripheral coating layer 4 locates, Fig. 1, [0023]), bonding material layers (Okumura’s bonding material layer 9, Fig. 1, [0024]) filling lattice gaps between said honeycomb segments for bonding them (Okumura Fig. 1, [0024]), and a skin layer (Okumura’s outer peripheral coating layer 4, Fig. 1, [0024]) enclosing the bonded honeycomb segments (see Okumura Fig. 1, [0024]).
Okumura does not disclose that limitation of that a cross section of each honeycomb segment perpendicular to its flow path direction having an octagonal shape obtained by providing a quadrilateral with a chamfer at each corner, which is alternately constituted by first outer peripheral walls corresponding to the sides of said quadrilateral, and second outer peripheral walls corresponding to said linear chamfers,
vacant intersection spaces free of said bonding material being formed in the intersections of said lattice gaps between the bonded honeycomb segments, whose contours are formed by said second outer peripheral walls, and
a space ratio (t2/tl) defined by a ratio of the diameter t2 of said vacant intersection space to the thickness tl of the bonding material layer between said first outer peripheral walls being more than 1.4.
In the analogous art of silicon carbide honeycomb structures, Shibata discloses a cross section of each honeycomb segment perpendicular to its flow path direction having an octagonal shape obtained by providing a quadrilateral with a chamfer at each corner (Shibata discloses its honeycomb fired body has a rectangular pillar shaped, and its corner portion may be chamfered with straight lines, thus reading on the claimed “octagonal shape”, Shibata Fig. 2A, [0293]), which is alternately constituted by first outer peripheral walls corresponding to the sides of said quadrilateral (Shibata’s outer wall portion 17, Shibata Fig. 2a, [0298]), and second outer peripheral walls corresponding to said linear chamfers Shibata’s chamfered portions 110B, Shibata Fig. 2A, [0299]),
vacant intersection spaces free of said bonding material being formed in the intersections of said lattice gaps between the bonded honeycomb segments, whose contours are formed by said second outer peripheral walls (see Shibata’s annotated Fig. 1).
Shibata discloses its octagonal shaped honeycomb fire body prevents thermal stress concentration at the corner portions to thereby prevent occurrence of damage of such as cracks, Shibata Fig. 2, [0293]. It would therefore have been obvious for one ordinary skill in the art at the time of filing to modify Okumura’s honeycomb segments 2 to have the same shape as disclosed by Shibata for the benefits disclosed.
While such modification does not disclose a space ratio (t2/tl) defined by a ratio of the diameter t2 of said vacant intersection space to the thickness tl of the bonding material layer between said first outer peripheral walls being more than 1.4, Shibata shows a configuration where t2 is at least twice the thickness of bonding material layer, which provides a t2/t1 falls within the claimed ratio of more than 1.4 and support a prima facie case of obviousness. MPEP 2144.05(I). Additionally, Okumura discloses the thickness of the bonding material layer is determined in consideration of a force for bonding the honeycomb segments 2 to one another, Okumura [0034]. And Shibata discloses its chamfered corner is introduced to prevent cracks and in addition to straight lines, it could also be curved, Shibata [0293]. It is therefore concluded that both t1 and t2 are result effective variables, because t1 affects the bonding force and t2 affects crack prevention ability. It would therefore have been obvious for one ordinary skill in the art at the time of filing to use routine optimization to optimize the ratio of t2/t1 to be within the claimed range for an optimum binding force between sections and optimum durability against cracks.
Furthermore, the instant disclosure does not teach the claimed space ratio is critical to the operation of the claimed invention. Therefore, absent evidence of criticality, this difference fails to patentably distinguish over prior art because it produces a difference in degree rather than in kind. MPEP 2044.05 (III)(A).
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Regarding Claim 3:
Okumura discloses that a silicon carbide honeycomb filter (Okumura’s honeycomb structure 1, Fig. 1, [0023]) constituted by honeycomb segments (Okumura’s honeycomb segments 2, Fig. 2, [0023]) each comprising cell walls (Okumura’s partition walls 6, Fig. 1, [0024]) forming cells (Okumura’s cells 5, Fig. 1, [0023]) defining pluralities of flow paths (Okumura discloses as fluid channels, Fig. 1, [0023]) longitudinally extending between both end surfaces (Okumura’s left and end portions as best shown in Fig. 4),
plugs sealing (Okumura’s filling material 7, Fig. 2, [0024] end surfaces of said cells alternately in a checkerboard pattern (as shown in Fig. 2 of Okumura),
and an outer peripheral wall (Okumura’s outer peripheral surface of the bonding honeycomb segment article 10, where outer peripheral coating layer 4 locates, Fig. 1, [0023]), bonding material layers (Okumura’s bonding material layer 9, Fig. 1, [0024]) filling lattice gaps between said honeycomb segments for bonding them (Okumura Fig. 1, [0024]), and a skin layer (Okumura’s outer peripheral coating layer 4, Fig. 1, [0024]) enclosing the bonded honeycomb segments (see Okumura Fig. 1, [0024]),
said lattice gaps (as shown in Okumura Fig. 5, space between the partial bonding material layers 9, Fig. 5, [0027]) being provided with a bonding-material-free region extending in four directions from a center intersection to adjacent intersections (best shown in Okumura Fig. 2), wherein said center intersection is an intersection located at the center axis of said honeycomb filter (best shown in Okumura Fig. 2) or its nearby position among intersections of said lattice gaps.
Okumura does not disclose that limitation of that a cross section of each honeycomb segment perpendicular to its flow path direction having an octagonal shape obtained by providing a quadrilateral with a chamfer at each corner, which is alternately constituted by first outer peripheral walls corresponding to the sides of said quadrilateral, and second outer peripheral walls corresponding to said linear chamfers,
vacant intersection spaces free of said bonding material being formed in the intersections of said lattice gaps between the bonded honeycomb segments, whose contours are formed by said second outer peripheral walls, and
a space ratio (t2/tl) defined by a ratio of the diameter t2 of said vacant intersection space to the thickness tl of the bonding material layer between said first outer peripheral walls being more than 1.4.
In the analogous art of silicon carbide honeycomb structures, Shibata discloses a cross section of each honeycomb segment perpendicular to its flow path direction having an octagonal shape obtained by providing a quadrilateral with a chamfer at each corner (Shibata discloses its honeycomb fired body has a rectangular pillar shaped, and its corner portion may be chamfered with straight lines, thus reading on the claimed “octagonal shape”, Shibata Fig. 2A, [0293]), which is alternately constituted by first outer peripheral walls corresponding to the sides of said quadrilateral (Shibata’s outer wall portion 17, Shibata Fig. 2a, [0298]), and second outer peripheral walls corresponding to said linear chamfers Shibata’s chamfered portions 110B, Shibata Fig. 2A, [0299]),
vacant intersection spaces free of said bonding material being formed in the intersections of said lattice gaps between the bonded honeycomb segments, whose contours are formed by said second outer peripheral walls (see Shibata’s annotated Fig. 1).
Shibata discloses its octagonal shaped honeycomb fire body prevents thermal stress concentration at the corner portions to thereby prevent occurrence of damage of such as cracks, Shibata Fig. 2, [0293]. It would therefore have been obvious for one ordinary skill in the art at the time of filing to modify Okumura’s honeycomb segments 2 to have the same shape as disclosed by Shibata for the benefits disclosed.
While such modification does not disclose a space ratio (t2/tl) defined by a ratio of the diameter t2 of said vacant intersection space to the thickness tl of the bonding material layer between said first outer peripheral walls being more than 1.4, Shibata shows a configuration where t2 is at least twice the thickness of bonding material layer, which provides a t2/t1 falls within the claimed ratio of more than 1.4 and support a prima facie case of obviousness. MPEP 2144.05(I). Additionally, Okumura discloses the thickness of the bonding material layer is determined in consideration of a force for bonding the honeycomb segments 2 to one another, Okumura [0034]. And Shibata discloses its chamfered corner is introduced to prevent cracks and in addition to straight lines, it could also be curved, Shibata [0293]. It is therefore concluded that both t1 and t2 are result effective variables, because t1 affects the bonding force and t2 affects crack prevention ability. It would therefore have been obvious for one ordinary skill in the art at the time of filing to use routine optimization to optimize the ratio of t2/t1 to be within the claimed range for an optimum binding force between sections and optimum durability against cracks.
Furthermore, the instant disclosure does not teach the claimed space ratio is critical to the operation of the claimed invention. Therefore, absent evidence of criticality, this difference fails to patentably distinguish over prior art because it produces a difference in degree rather than in kind. MPEP 2044.05 (III)(A).
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Regarding claim 4:
Modified Okumura does not disclose that the silicon carbide honeycomb filter according to claim 2, wherein said vacant intersection spaces occupy 30% or more of all intersections.
However, a person of ordinary skill in the art understands that the vacant intersection spaces occupying intersections is directly related with the number of honeycomb sections, and corner length of each octagon shaped honeycomb sections and the bonding material thickness. Those variables are related with honeycomb bonding force and crack prevention ability, as discussed in claim 2. It would therefore have been obvious for one ordinary skill in the art at the time of filing to use routine optimization to optimize the vacant intersection space ratio for the benefits of optimal bonding force and crack prevention ability.
Furthermore, the instant disclosure does not teach the claimed space ratio is critical to the operation of the claimed invention. Therefore, absent evidence of criticality, this difference fails to patentably distinguish over prior art because it produces a difference in degree rather than in kind. MPEP 2044.05 (III)(A).
Regarding claim 5:
Modified Okumura does not disclose that the silicon carbide honeycomb filter according to claim 3, wherein said vacant intersection spaces occupy 30% or more of all intersections.
However, a person of ordinary skill in the art understands that the vacant intersection spaces occupying intersections is directly related with the number of honeycomb sections, and corner length of each octagon shaped honeycomb sections and the bonding material thickness. Those variables are related with honeycomb bonding force and crack prevention ability, as discussed in claim 3. It would therefore have been obvious for one ordinary skill in the art at the time of filing to use routine optimization to optimize the vacant intersection space ratio for the benefits of optimal bonding force and crack prevention ability.
Furthermore, the instant disclosure does not teach the claimed space ratio is critical to the operation of the claimed invention. Therefore, absent evidence of criticality, this difference fails to patentably distinguish over prior art because it produces a difference in degree rather than in kind. MPEP 2044.05 (III)(A).
Regarding Claim 6:
Modified Okumura does not disclose that the silicon carbide honeycomb filter according to claim 2, wherein said space ratio is 1.5-5.
Shibata shows a configuration where t2 is at least twice the thickness of bonding material layer, which provides a t2/t1 falls within the claimed ratio of more than 1.4 and support a prima facie case of obviousness. MPEP 2144.05(I). Additionally, Okumura discloses the thickness of the bonding material layer is determined in consideration of a force for bonding the honeycomb segments 2 to one another, Okumura [0034]. And Shibata discloses its chamfered corner is introduced to prevent cracks and in addition to straight lines, it could also be curved, Shibata [0293]. It is therefore concluded that both t1 and t2 are result effective variables, because t1 affects the bonding force and t2 affects crack prevention ability. It would therefore have been obvious for one ordinary skill in the art at the time of filing to use routine optimization to optimize the ratio of t2/t1 to be within the claimed range for an optimum binding force between sections and optimum durability against cracks.
Furthermore, the instant disclosure does not teach the claimed space ratio is critical to the operation of the claimed invention. Therefore, absent evidence of criticality, this difference fails to patentably distinguish over prior art because it produces a difference in degree rather than in kind. MPEP 2044.05 (III)(A).
Regarding Claim 7:
Modified Okumura does not disclose that the silicon carbide honeycomb filter according to claim 3, wherein said space ratio is 1.5-5.
Shibata shows a configuration where t2 is at least twice the thickness of bonding material layer, which provides a t2/t1 falls within the claimed ratio of more than 1.4 and support a prima facie case of obviousness. MPEP 2144.05(I). Additionally, Okumura discloses the thickness of the bonding material layer is determined in consideration of a force for bonding the honeycomb segments 2 to one another, Okumura [0034]. And Shibata discloses its chamfered corner is introduced to prevent cracks and in addition to straight lines, it could also be curved, Shibata [0293]. It is therefore concluded that both t1 and t2 are result effective variables, because t1 affects the bonding force and t2 affects crack prevention ability. It would therefore have been obvious for one ordinary skill in the art at the time of filing to use routine optimization to optimize the ratio of t2/t1 to be within the claimed range for an optimum binding force between sections and optimum durability against cracks.
Furthermore, the instant disclosure does not teach the claimed space ratio is critical to the operation of the claimed invention. Therefore, absent evidence of criticality, this difference fails to patentably distinguish over prior art because it produces a difference in degree rather than in kind. MPEP 2044.05 (III)(A).
Regarding claim 9:
Modified Okumura discloses that the silicon carbide honeycomb filter according to claim 2, wherein said outer peripheral wall of each honeycomb segment is thicker than said cell walls (Okumura discloses an example 1, where the partition wall thickness is 310 mu.m and an outer wall thickess is 1 mm, which is thicker than the cell walls, Okumura [0039]).
Regarding claim 10:
Modified Okumura discloses that the silicon carbide honeycomb filter according to claim 3, wherein said outer peripheral wall of each honeycomb segment is thicker than said cell walls (Okumura discloses an example 1, where the partition wall thickness is 310 mu.m and an outer wall thickess is 1 mm, which is thicker than the cell walls, Okumura [0039]).
Claims 11–12 are rejected under 35 U.S.C. 103 as being unpatentable over Okumura in view of Shibata, and in further view of Yamaguchi et al., JP 2013198884 A ("Yamaguchi”).
Regarding claim 11:
Modified Okumura does not disclose that the silicon carbide honeycomb filter according to claim 2, wherein a cross section of said second outer peripheral wall perpendicular to its flow path direction has a triangular shape constituted by two cell walls extending vertically and horizontally and closest to said second outer peripheral wall and an outer peripheral surface of said second outer peripheral wall, and the radial maximum thickness of said second outer peripheral wall defined by the distance between the center vertex of said triangular shape and said outer peripheral surface is larger than the thickness of said first outer peripheral wall.
In the analogous art of honeycomb structure comprising octagon shaped honeycomb sections, Yamaguchi discloses an honeycomb section as shown in Fig. 5, wherein a cross section of said second outer peripheral wall perpendicular to its flow path direction has a triangular shape (as shown in Yamaguchi, Fig. 5, top right corner) constituted by two cell walls (Yamaguchi’s wall next to label 11b and 11c, Yamaguchi Fig. 5, p. 5) extending vertically and horizontally and closest to said second outer peripheral wall (Yamaguchi’s inclined surface 70, Fig. 5, p. 5) and an outer peripheral surface of said second outer peripheral wall (where label 70 points, Yamaguchi Fig. 5), and the radial maximum thickness of said second outer peripheral wall defined by the distance between the center vertex of said triangular shape and said outer peripheral surface is larger than the thickness of said first outer peripheral wall (as shown in Fig. 5 of Yamaguchi). Yamaguchi discloses that with its configuration, the corner portion does not have a relatively sharp angle such as 90 degrees, and it is possible to prevent the corner portion from being chipped or cracking from occurring at the joint portion 3 starting from the corner portion, Yamaguchi Fig. 5, p. 5. It would therefore have been obvious for one ordinary skill in the art at the time of filing to further modify Okumura for the benefits disclosed.
Regarding claim 12:
Modified Okumura does not disclose that the silicon carbide honeycomb filter according to claim 3, wherein a cross section of said second outer peripheral wall perpendicular to its flow path direction has a triangular shape constituted by two cell walls extending vertically and horizontally and closest to said second outer peripheral wall and an outer peripheral surface of said second outer peripheral wall, and the radial maximum thickness of said second outer peripheral wall defined by the distance between the center vertex of said triangular shape and said outer peripheral surface is larger than the thickness of said first outer peripheral wall.
In the analogous art of honeycomb structure comprising octagon shaped honeycomb sections, Yamaguchi discloses an honeycomb section as shown in Fig. 5, wherein a cross section of said second outer peripheral wall perpendicular to its flow path direction has a triangular shape (as shown in Yamaguchi, Fig. 5, top right corner) constituted by two cell walls (Yamaguchi’s wall next to label 11b and 11c, Yamaguchi Fig. 5, p. 5) extending vertically and horizontally and closest to said second outer peripheral wall (Yamaguchi’s inclined surface 70, Fig. 5, p. 5) and an outer peripheral surface of said second outer peripheral wall (where label 70 points, Yamaguchi Fig. 5), and the radial maximum thickness of said second outer peripheral wall defined by the distance between the center vertex of said triangular shape and said outer peripheral surface is larger than the thickness of said first outer peripheral wall (as shown in Fig. 5 of Yamaguchi). Yamaguchi discloses that with its configuration, the corner portion does not have a relatively sharp angle such as 90 degrees, and it is possible to prevent the corner portion from being chipped or cracking from occurring at the joint portion 3 starting from the corner portion, Yamaguchi Fig. 5, p. 5. It would therefore have been obvious for one ordinary skill in the art at the time of filing to further modify Okumura for the benefits disclosed.
Claim 14 is rejected under 35 U.S.C. 103 as being unpatentable over Okumura in view of Beall et al., US 2019/0374896 A1 (“Beall”).
Regarding claim 14:
Modified Okumura does not disclose that the silicon carbide honeycomb filter according to claim 1, wherein in a cross section perpendicular to the flow path direction, the cross section area of an introducing cell whose outlet-side end surface is sealed is larger than the cross section area of a discharging cell whose inlet-side end surface is sealed.
In the analogous art honeycomb structures, Beall discloses that some honeycomb structure is modified to include inlet channels having larger cross-sectional area than the outlet channels to effectively reduce the severity of pressure drop increases as soot and ash loading increase overtime, Beall [0004]. It would therefore have been obvious for one ordinary skill in the art at the time of filing to modify Okumura to have larger cross sectional area of its introducing cell for the benefits disclosed above.
Claims 15–16 are rejected under 35 U.S.C. 103 as being unpatentable over Okumura in view of Shibata, and in further view of Beall.
Regarding claim 15:
Modified Okumura does not disclose that the silicon carbide honeycomb filter according to claim 2, wherein in a cross section perpendicular to the flow path direction, the cross section area of an introducing cell whose outlet-side end surface is sealed is larger than the cross section area of a discharging cell whose inlet-side end surface is sealed.
In the analogous art honeycomb structures, Beall discloses that some honeycomb structure is modified to include inlet channels having larger cross-sectional area than the outlet channels to effectively reduce the severity of pressure drop increases as soot and ash loading increase overtime, Beall [0004]. It would therefore have been obvious for one ordinary skill in the art at the time of filing to modify Okumura to have larger cross sectional area of its introducing cell for the benefits disclosed above.
Regarding claim 16:
Modified Okumura does not disclose that the silicon carbide honeycomb filter according to claim 3, wherein in a cross section perpendicular to the flow path direction, the cross section area of an introducing cell whose outlet-side end surface is sealed is larger than the cross section area of a discharging cell whose inlet-side end surface is sealed.
In the analogous art honeycomb structures, Beall discloses that some honeycomb structure is modified to include inlet channels having larger cross-sectional area than the outlet channels to effectively reduce the severity of pressure drop increases as soot and ash loading increase overtime, Beall [0004]. It would therefore have been obvious for one ordinary skill in the art at the time of filing to modify Okumura to have larger cross sectional area of its introducing cell for the benefits disclosed above.
Conclusion
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/Qianping He/Examiner, Art Unit 1776
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