Ex Parte Nishikawa et al

Patent Trial and Appeal Board

May 23, 2013

10432439 (P.T.A.B. May. 23, 2013)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE PATENT TRIAL AND APPEAL BOARD
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Ex parte NAOKI NISHIKAWA, KOICHIRO TAKE, and
NOBORU OGASAWARA
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Appeal 2011-001289
Application 10/432,439
Technology Center 3700
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Before: STEFAN STAICOVICI, BENJAMIN D. M. WOOD, and
JOHN W. MORRISON, Administrative Patent Judges.

WOOD, Administrative Patent Judge.

DECISION ON APPEAL

Appeal 2011-001289
Application 10/432,439

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STATEMENT OF CASE
Appellants appeal under 35 U.S.C. § 134 from a rejection of claims 1,
3, 6, 8, and 10. Claims 2, 4, 5, 7, 9 and 11-14 have been canceled. We have
jurisdiction under 35 U.S.C. § 6(b).
We reverse.
THE INVENTION
The claims are directed to a heat exchanger tube and heat exchanger
for car air conditioners. Spec. 1, ll. 7-11. Claim 1, reproduced below, is
illustrative of the claimed subject matter:
1. A heat exchanger tube provided with a flat tube
main body with a certain length and having a plurality
of refrigerant flow passages each extending in a tube
longitudinal direction and disposed in parallel in a
tube widthwise direction,
wherein the following relations are established:
Ac/At x 100 = 30 to 45; and
P/L x 100 = 200 to 325,
wherein a total cross-sectional area of the tube
main body (including the refrigerant passage portions)
is “At”; a total cross-sectional area of the refrigerant
flow passages is “Ac”; an external peripheral length
of the tube main body is “L”; and a total internal
peripheral length of the refrigerant passages is “P”,
wherein the relation of H=0.5 to 1.5 mm is
established, wherein a height of the tube main body is
“H”, and
wherein the relation of W=10 to 20 mm is
established, wherein a width of the tube main body is
“W”.

Appeal 2011-001289
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REFERENCE
Tanaka US 5,476,141 Dec. 19, 1995
REJECTION
Claims 1, 3, 6, 8, and 10 stand rejected under 35 U.S.C. §103(a) as
unpatentable over Tanaka. Ans. 3.
ANALYSIS
Independent claim 1 calls for an air conditioner heat exchanger with
flat tubes, each tube having a certain length and having a plurality of
longitudinal refrigerant flow passages that satisfy several dimensional
relationships: (1) the ratio of the total cross-sectional area of the refrigerant
flow passages, Ac, over the total cross-sectional area of the tube main body,
At, times 100, must be between 30 to 45 (hereinafter “Ac/At”); (2) the ratio
of the total internal “peripheral length”1 of the refrigerant passages, P, over
the external peripheral length of the tube main body, L, times 100, must be
between 200 to 325 (hereinafter “P/L”); (3) the height, H, of the tube main
body must be between 0.5 and 1.5 mm; and (4) the width, W, of the tube
main body must be between 10 to 20 mm. App. Br. 10. Independent Claim
10 contains similar limitations. Id. at 11. Claims 3, 6, and 8 depend from
claim 1. Id. at 10-11.
The Examiner found that Tanaka discloses a heat exchanger with
tubes having the basic structure recited in claim 1. Ans. 3 (citing Tanaka,

1 “Peripheral length” apparently means cross-sectional perimeter; that is, P
refers to the total cross-sectional perimeter of the refrigerant passages, and L
refers to the cross-sectional perimeter of the tube main body. This can be
discerned from observing in Table 1 (Spec. 20) that L, the peripheral length
of the tube main body, is slightly less than twice the total of the height and
width of the tube main body, which one would expect the perimeter of the
roughly rectangular tube main body to be.
Appeal 2011-001289
Application 10/432,439

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figs. 1, 3-4). The Examiner acknowledged that Tanaka does not disclose the
claimed dimensional relationships, but found that such limitations are
“results effective variables, which one of ordinary skill in the art would
optimize based on the intended use and desired characteristics of the
device.” Id. at 3-4. For example, the Examiner noted that “Tanaka fails to
explicitly disclose that the ratio of the cross sectional area of the refrigerant
flow passages to the cross sectional area of the tube main body times 100
equals 30 to 45,” but found that Tanaka’s “refrigerant flow channels are
formed in the tube and necessarily constitute a defined percentage of the
tube area.” Id. at 4. The Examiner reasoned that
the percentage of the tube member that is made up of
refrigerant flow channels is recognized as a result-effective
variable, i.e. a variable which achieves [the] recognized result
[that] a smaller percentage of the tube constituted by the
refrigerant flow channels results in thicker walls and a stronger
tube, but reduced heat transfer through the tube walls, and a
larger percentage of the tube constituted by the refrigerant flow
channels results in thinner walls and a weaker tube, but
increased heat transfer.
Id. The Examiner concluded that “since the general conditions of the claim,
i.e. that the tube is made up of a defined percentage of refrigerant flow
channels, were disclosed in the prior art by Tanaka, it is not inventive to
discover the optimum workable range by routine experimentation.” Id. The
Examiner made similar findings with respect to the height, width, and
peripheral-length ratio limitations. Id. at 6-8. Appellants respond that the
Examiner has not shown that the “claimed variable[s are] known and that the
[variables are] known to effect the result for which [the] claimed range is
directed.” App. Br. 5.
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“[W]here the general conditions of a claim are disclosed in the prior
art, it is not inventive to discover the optimum or workable ranges by routine
experimentation.” In re Aller, 220 F.2d 454, 456 (CCPA 1955). This rule is
limited to cases in which the optimized variable is a “result-effective
variable.” In re Antonie, 559 F.2d 618, 620 (CCPA 1977); see In re Boesch,
617 F.2d 272, 276 (CCPA 1980) (“[D]iscovery of an optimum value of a
result effective variable ... is ordinarily within the skill of the art.”).
While the Examiner is correct that Tanaka’s tube necessarily has some
Ac/At, P/L, height and width, just as any tube with passages would have, the
Examiner has not shown where Tanaka specifies any particular values for
these parameters, provides sufficient information to permit values to be
determined, or otherwise provides support for the Examiner’s finding that a
person of ordinary skill would have considered these parameters to be result-
effective variables. More specifically, the Examiner’s general statements
regarding the effect of tube Ac/At, P/L, height and width on fluid flow/heat
transfer (see Ans. 4-7) amounts to varying every geometrical parameter of
Tanaka in order to optimize the performance of Tanaka’s tube. See also
Ans. 82. While geometric parameters such as height, weight, flow channel
area and perimeter length are known to describe a heat exchanger tube, this
does not mean that every heat exchanger tube configuration is obvious to try,
without evidence or reasoning tending to demonstrate the obviousness of the
particularly claimed configuration. As noted by Appellants, the claimed
Ac/At, P/L, height and width together “provide for a reduction[] in

2 “That Tanaka does not give specific values for the sizes and
proportions of the parts of the device is considered by the examiner to be
evidence that selecting the sizes and proportions for the device are well
within the level of ordinary skill in the art.”
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size/weight without deteriorating performance” of the heat exchanger tube.
App. Br. 3. In contrast, the Examiner has not shown that Ac/At, P/L, height
and width together achieve a recognized result. As such, the Examiner has
not shown by a preponderance of the evidence that the claimed dimensional
relationships are result effective.
Because the Examiner has not shown that all of the claimed
dimensional limitations are result-effective, we do not sustain the
Examiner’s obviousness rejection of claims 1, 3, 6, 8, and 10.
DECISION
For the above reasons, the Examiner’s rejection of claims 1, 3, 6, 8,
and 10 as obvious over Tanaka is reversed.

REVERSED

mls