Kenichiro Mitsuhashi

Patent Trials and Appeals Board

Sep 9, 2019

13910335 - (D) (P.T.A.B. Sep. 9, 2019)

UNITED STATES PATENT AND TRADEMARK OFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
13/910,335 06/05/2013 Kenichiro MITSUHASHI 416795US41 1691
22850 7590 09/09/2019
OBLON, MCCLELLAND, MAIER & NEUSTADT, L.L.P.
1940 DUKE STREET
ALEXANDRIA, VA 22314
EXAMINER
DIAZ, MARCOS O
ART UNIT PAPER NUMBER
3741
NOTIFICATION DATE DELIVERY MODE
09/09/2019 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
OBLONPAT@OBLON.COM
iahmadi@oblon.com
patentdocket@oblon.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
____________________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________________

Ex parte KENICHIRO MITSUHASHI
____________________

Appeal 2018-000479
Application 13/910,335
Technology Center 3700
____________________

Before STEFAN STAICOVICI, MEREDITH C. PETRAVICK, and
LYNNE H. BROWNE, Administrative Patent Judges.

BROWNE, Administrative Patent Judge.

DECISION ON APPEAL

STATEMENT OF THE CASE
Appellant appeals under 35 U.S.C. § 134 from the rejection of claims
1–5 and 8–13 under 35 U.S.C. § 103(a) as unpatentable over Mitsuhashi (US
2010/0263823 A1, pub. Oct. 21, 2010) and Bjork (US 2007/0137841 A1;
pub. June 21, 2007). We have jurisdiction over this appeal under 35 U.S.C.
§ 6(b). An oral hearing was held on August 20, 2019.
We affirm.

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CLAIMED SUBJECT MATTER
The claims are directed to a plate fin heat exchanger. Sole
independent claim 1, reproduced below, is representative of the claimed
subject matter:
1. A plate fin heat exchanger, comprising:
a heat exchange unit inside which a plurality of flow
passages is provided so as to be layered and heat exchange is
performed between fluids flowing through the flow passages;
and
a pair of protection units arranged on both outer sides of
said heat exchange unit in the layering direction of the flow
passages, the protection units for protecting said heat exchange
unit,
wherein said heat exchange unit has a plurality of
partition walls aligned at intervals in such a manner that each of
the flow passages is formed between adjacent pairs of said
partition walls, and a heat exchange unit fin plate which is
arranged in each respective flow passage for coupling said
partition walls facing each other across the flow passage,
a protection unit of said protection units has a protection
unit main body attached to the outermost partition wall so as to
form an internal space between said protection unit main body
and said outermost partition wall, and a protection unit fin plate
arranged in the internal space of said protection unit main body,
the protection unit fin plate for coupling an outer surface of said
outermost partition wall and an inner surface of said protection
unit main body facing the outer surface,
a release portion for, in a case where the fluid flows into
the internal space, releasing the fluid to an exterior is provided
in said protection unit main body of said protection unit, and
said protection unit fin plate of said protection unit has a
strength greater than a strength of at least one of the heat
exchange fin plates of said heat exchange unit, such that a
coupling state between the outer surface of said outermost
partition wall and the inner surface of said protection unit main
body facing the outer surface is maintained even in a case
where an inner pressure set as a design pressure for a part of
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said heat exchange unit constituting the outermost-layer flow
passage adjacent to said protection unit is applied to the internal
space of said protection unit main body of said protection unit.

DISCUSSION
Claims 1, 3–5, 9, 10, 12, and 13
Claims 3–5, 9, 10, 12, and 13 depend from claim 1. Appeal Br. 10–13
(Claims App.). Appellant does not provide separate arguments for the
patentability of claims 3–5, 9, 10, 12, and 13. Accordingly, claims 3–5, 9,
10, 12, and 13 stand or fall with claim 1.
The Examiner finds that Mitsuhashi discloses all of the limitations of
claim 1 except for a “protection unit fin plate of said protection unit [that]
has a strength greater than a strength of at least one of the heat exchange fin
plates of said heat exchange unit.” Final Act. 4. The Examiner further finds
that Bjork “teaches strengthening the fins of a heat exchanger at the areas of
highest stress accumulation in order for the heat exchanger to be efficient
under the operating conditions, [t]hereby maximizing the thermal fatigue life
of the heat exchanger while retaining heat exchange properties.” Id. (citing
Bjork, Abstract, ¶ 19). Given these findings, the Examiner reasons that
since Mitsuhashi discloses that stress accumulation and thermal
expansion is highest on the outermost partition and fin plates
(par 0041,par 0050), or protection unit fin plates, it would have
been obvious to one of ordinary skill in the art at the time the
invention was made to modify Mitsuhashi with said protection
unit fin plate of said protection unit has a strength greater than a
strength of at least one of the heat exchange fin plates of said
heat exchange unit, as taught by Bjork, for the purpose of
strengthening the protection unit fin plates, which have the
areas of highest stress accumulation, in order for the heat
exchanger to be efficient under the operating conditions,
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thereby maximizing the thermal fatigue life of the heat
exchanger while retaining heat exchange properties.
Id.
Appellant contends that Mitsuhashi teaches away from the proposed
combination based on the following reasoning. Appeal Br. 6–7.
Acknowledging that “Mitsuhashi recognizes that fatigue based on the
thermal stress is accumulated in the conventional partition plate 102 which
separates the protection part 110 (Fig. 4B) from the interior flow passages,
whereby this partition plate can crack and leak fluid into the protection part
110 (paragraphs [0009]-[0010]),” and that “Mitsuhashi further recognizes
that it had been considered to address this problem by enhancing the rigidity
of the interior fin plates l04 forming the flow passages r, to prevent the
cracking of partition plate 102,” Appellant argues that Mitsuhashi “rejects
such reinforcement of the interior fin plates 104 forming the flow passages r
because the heat conductivity of the fin plates 104 would thereby be
reduced, resulting in deterioration of the performance of the heat
exchanger.” Id. at 6 (citing Mitsuhashi ¶¶ 11–12) (internal quotation
omitted). Appellant explains that “Mitsuhashi provides a pair of sensing
parts 35 on both outer sides of the heat exchange unit.” Id. According to
Appellant “[i]n the sensing parts 35, a sensor plate (sensor wall) 36, which is
one of the partition plates 33, is more easily damaged by the thermal stress
based on the heat of the fluid flowing in the flow passage 30 than the other
partition plates 33” and “[a] detector 50 detects damage of the sensor plate
36, whereby the fatigue due to thermal stress can be detected without
external fluid leakage.” Id. (citing Mitsuhashi ¶¶ 40, 53). Appellant
explains further that in Mitsuhashi,
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“the same plate is used for the partition plate 33 of the sensing
part 35 and the partition plate 33 of the heat exchange part 3,
and the same plate is used for the fin plate 32a of the sensing
part 35 and the fin plate 32 of the heat exchange part 3 . . .
Therefore, the sensing part 35 has strength enough to endure a
situation such that the pressure in the sealed space 30c is equal
to the pressure in the flow passage 30 with the high pressure
fluid F1 or F2 in the heat exchange part 3 flowing therein.”
Appeal Br. 6 (quoting Mitsuhashi ¶ 42). Based on this reasoning, Appellant
concludes that “Mitsuhashi teaches away from enhancing the rigidity of the
fin plates of a layered heat exchanger to prevent cracking of the outer
partition plate, because it reduces heat exchanger performance . . . it teaches
away from enhancing the strength of heat exchange fin plates of a heat
exchange unit.” Id. at 7 (citing Mitsuhashi ¶¶ 11–12).
First, we note, that in paragraphs 11 and 12, Mitsuhashi is specifically
concerned with the rigidity of fin plate 104. Mitsuhashi ¶¶ 11–12. Fin plate
104 is, as noted by Appellant above, an interior fin plate, which is not a part
of the protection parts 110. See id., Fig. 5. The rejection proposes
modifying the protection unit fin plate, not an interior fin plate. See Final
Act. 4. Thus, even if Mitsuhashi teaches away from modification of an
interior fin plate, it does not teaches away from modification of a protection
unit fin plate. Accordingly, Appellant’s argument is unconvincing.
Appellant also argues that “Mitsuhashi does not appear to recognize
the problem that if the sensing part 35 only has the same strength as the heat
exchanger, it is susceptible to failure due to the same cause that produced
failure and leakage in the heat exchanger.” Appeal Br. 7. We, however, are
not aware of any requirement that it do so. Rather, a determination of
obviousness does not require the claimed invention to be expressly
suggested by any one or all of the references. See, e.g., In re Keller, 642
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F.2d 413, 425 (CCPA 1981). Accordingly, Appellant’s argument does not
apprise us of error.
Appellant also notes that “unlike the heat exchange fin plates forming
the flow passages in Mitsuhashi, the fin plate of the protection unit only
carries heat exchange fluid in the case of a malfunction – e.g., in case of
cracking of the partition plate 102.” Appeal Br. 7 (emphasis omitted). In
view of this difference, Appellant contends that the “construction [of the
protection unit] does not affect heat exchange efficiency during normal
operation.” Id. (emphasis omitted); see also Reply Br. 2. Appellant’s
argument is inapposite, because the rejection does not rely on “efficien[cy]
under [normal] operating conditions” as the reason for the proposed
modification. Rather, even though the rejection mentions maintaining the
efficiency of the heat exchanger under the operating conditions, the reason
for the proposed modification is to “mazimiz[e] the thermal fatigue life of
the heat exchanger while retaining heat exchange properties.” Final Act. 4.
Next, acknowledging that Bjork “broadly suggests that a part of a heat
exchanger should have sufficient thickness and strength to withstand the
stresses which it is expected to encounter,” Appellant argues that “it would
not have induced one skilled in the art to modify Mitsuhashi according to the
invention.” Appeal Br. 7. According to Appellant, Bjork “only teaches
(paragraphs [0019]–[0020]) that a heat exchange fin should be locally
thickened at the portion where it is brazed to the heat exchange core, to
account for brazing induced stresses.” Id.
We do not understand Bjork’s teaching to be so limited. For example,
in paragraph 19 Bjork describes strengthening of specific locations such and
gives examples such as where the fin meets other elements, as in the tubes or
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the header. Bjork ¶ 19. We see nothing in Bjork that limits its teaching to
only those areas.
In rejecting claim 1, the Examiner finds that “Mitsuhashi discloses
that stress accumulation and thermal expansion is highest on the outermost
partition and fin plates (par[a.] 0041,par[a.] 0050), or protection unit fin
plates.” Final Act. 4. Appellant does not contest this finding. See
generally, Appeal Br. The Examiner reasons that it would be obvious to a
skilled artisan to modify Mitsuhashi’s area of highest stress in view of
Bjork’s teaching of strengthening the area of highest stress. See Final Act.
4. Appellant’s argument above do not apprise us error in this reasoning.
Appellant concludes his arguments in the Appeal Brief by contending
that
one skilled in the art would not consider it obvious to apply this
broad teaching of Bjork to instead strengthen the fin plate of the
protection unit 110 in Mitsuhashi, as compared to the interior fin
plates 104, without a recognition that: (i) the resulting reduced
heat exchange performance would not be problematic during
normal operation, and (2) that the fin plate of the protection unit
110 is subject to greater stress than the interior fin plate 104.
Appeal Br. 8. As noted by Appellant, however, Mitsuhashi teaches that it
was known to strengthen the fin plates of a heat exchanger. See id. at 8.
Although, Mitsuhashi may teach away from strengthening interior fin plates,
Appellant has not identified where Mitsuhashi discourages strengthening the
fin plates in the protection unit. Rather, by noting that such practice was a
known improvement, and singling out interior fin plates as not good
candidates for such modification, Mitsuhashi at least implies that
strengthening of other fin plates is a known improvement. Thus, Appellant’s
argument is unconvincing.
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In the Reply Brief, Appellant argues that Mitsuhashi does not meet the
limitation requiring “that the protection unit fin plate has a ‘strength greater
than a strength of at least one of the heat exchange fin plates of said heat
exchange unit,’” because Mitsuhashi states that
the same plate is used for the partition plate 33 of the sensing part
35 and the partition plate 33 of the heat exchange part 3, and the
same plate is used for the fin plate 32a of the sensing part 35 and
the fin plate 32 of the heat exchange part 3.
Reply Br. 1 (emphasis omitted).
Appellant’s argument is not responsive the rejection as articulated by
the Examiner which modifies Mitsuhashi’s protection unit fin plate to have a
strength greater than the strength of at least one of the heat exchanger fin
plates. See Final Act. 4. Moreover, Appellant cannot show nonobviousness
by attacking references individually where the rejections are based on
combinations of references. In re Merck & Co., Inc., 800 F.2d 1091, 1097
(Fed. Cir. 1986).
Finally, Appellant argues that
the strengthening of a fin in Bjork at, e.g., “at specific location
or locations where the fin meets other elements” (paragraph
[0019]) would not motivate one skilled in the art to disregard the
concern for reduced heat exchange performance in Mitsuhashi
and provide the protection unit fin plate with a strength greater
than a strength of at least one of the heat exchange fin plates of
the heat exchange unit.
Reply Br. 2 (emphasis omitted). The rejection, however, does not disregard
Mitsuhashi’s concern about reduced heat exchange performance. Rather, as
discussed above, the proposed modification takes Mitsuhashi’s warning into
account by only modifying the fin plates of the protection unit. See Final
Act. 4.
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For these reasons, we sustain the Examiner’s decision rejecting claim
1, and claims 3–5, 9, 10, 12, and 13, which depend therefrom, as
unpatentable over Mitsuhashi and Bjork.
Claim 2
Appellant contends that Bjork “does not suggest that a protection unit
fin plate of a protection unit should have has a pressure-resistance strength
which is greater than a pressure-resistance strength of the heat exchange
unit fin plate arranged in an outermost-layer flow passage adjacent to the
protection unit.” Appeal Br. 8.
In response, the Examiner explains that “[t]he strengthening of the
fins in view of Bjork refers to the pressure-resistance strength of the fins (see
par[a.] 0019 of Bjork), and upon modification, strengthening the protection
unit fins of Mitsuhashi also includes increased pressure-resistance strength.”
Ans. 6.
In paragraph 19, Bjork states, “[a] strengthened fin is designed to be
applied to localized areas in the heat exchanger where temperature/pressure
stress resistance greater than provided by a lower gage fin is required to
meet durability requirements while retaining some heat transfer properties.”
Bjork ¶ 19. Thus, we agree with the Examiner that Bjork suggests greater
pressure-resistance strength in the modified fin.
For this reason, we sustain the Examiner’s decision rejecting claim 2.
Claims 8 and 11
Appellant contends that the rejection of these claims “depends on a
misreading of [c]laims 8 and 11.” Appeal Br. 8. In support of this
contention, Appellant explains that “[c]laims 8 and 11 recite that a spacing
‘of’ the fins of the protection unit fin plate is smaller, not that a spacing
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‘between’ the fins is smaller.” Id. at 8–9. According to Appellant, “[e]ven
though thickening of the plates will result in a reduced space ‘between’ the
outer surfaces of the fins where the spacing ‘of’ the fins (i.e., between fin
centers) is unchanged, the spacing ‘of’ the fins will not thereby be altered.”
Id. at 9.
The Examiner responds that ‘“a spacing of the fins’ . . . can be
broadly interpreted to any type of spacing” of the fins. Ans. 7. For example,
the Examiner determines that “a spacing of the fins” can reasonably be
interpreted “as a space from surface-to-surface of a thickened fin of the
protection unit.” Id. Thus, according to the Examiner, “the space from the
thickened surface-to- thickened surface of the thickened fin would be less
than the space of a heat exchange unit fin which has not been thickened.”
Id.
Claims 8 and 11 do not specify how “a spacing of the fins” is
measured. Appeal. Br. 12 (Claims App.). The Specification does not
provide guidance on how such measurements would be taken. See generally
Spec. Nor does the term “spacing” appear to be a term of art. Accordingly,
we agree with the Examiner that “a spacing of the fins” is broad enough to
reasonably encompass the spacing between the fins, which would be smaller
between the fins in the protector unit than between the fins of the heat
exchanger when the modification proposed by the Examiner is implemented.
For this reason, we sustain the Examiner’s decision rejecting claims 8
and 11.

DECISION
The Examiner’s rejection of claims 1–5 and 8–13 is AFFIRMED.
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No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a). See 37 C.F.R.
§ 1.136(a)(1)(iv).

AFFIRMED