Ex Parte Smith et al

Board of Patent Appeals and Interferences

Mar 3, 2009

09956723 (B.P.A.I. Mar. 3, 2009)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte DANIEL JOHN SMITH, HUSSEIN KADHUM, and
MALCOLM DAVID SMITH
____________

Appeal 2009-0266
Application 09/956,723
Technology Center 3700
____________

Decided: March 3, 20091
____________

Before ERIC GRIMES, RICHARD M. LEBOVITZ, and STEPHEN
WALSH, Administrative Patent Judges.

LEBOVITZ, Administrative Patent Judge.

1 The two-month time period for filing an appeal or commencing a civil
action, as recited in 37 C.F.R. § 1.304, begins to run from the decided date
shown on this page of the decision. The time period does not run from the
Mail Date (paper delivery) or Notification Date (electronic delivery).

Appeal 2009-0266
Application 09/956,723

DECISION ON APPEAL
This is a decision on appeal from the Examiner’s final rejection of
claims 1-13. Jurisdiction for this appeal is under 35 U.S.C. § 6(b). We
affirm.
STATEMENT OF THE CASE
The claims are directed to a humidification apparatus for providing
humidified gases to a patient or person in need of such gases. The apparatus
comprises a humidification chamber, a chamber heating means for
vaporizing water, and a pathway along which the gas is conveyed to the
patient (Spec. 3). The pathway comprises a “self-regulating conduit heating
means” which the Specification exemplifies as being made from a positive
temperature coefficient (“PTC”) material (id. at 5). “The resistance of a
PTC material increases markedly once it reaches a threshold temperature,
resulting in reduced power consumption and subsequent cooling” (id. at 7).
According to the Specification, the humidification apparatus addresses
certain disadvantages of the prior art devices, including of having gases lose
humidity as they move along the gas transportation pathway, the occurrence
of condensation in the gas pathway which carries the gas to the patient, and
the bulk and weight of prior art devices (id. at 2).
Claims 1-13 are pending and appealed. The claims stand rejected by
the Examiner as failing to comply with the nonobviousness requirement of
35 U.S.C. § 103(a) in view of Gradon (US 6,349,722 B1, Feb. 26, 2002),
Huddart (US 5,640,951, Jun. 24, 1997), Hirtz (translation of DE 33 11 811
A1, Oct. 4, 1984), and any of Horsma (US 4,177,376, Dec. 4, 1979), Hurko
Appeal 2009-0266
Application 09/956,723

(US 4,808,793, Feb. 28, 1989), or Kamath (US 4,459,473, Jul. 10, 1984)
(Ans.2 4).
Claim 1, which is the only independent claim on appeal, reads as
follows:
1. A humidification apparatus for providing a humidified gases
flow to a patient or other person in need of such gases
comprising:
humidification chamber means, having an inlet and an
outlet to allow said gases flow to pass through said
humidification chamber means,
chamber heating means provided adjacent said
humidification chamber means and adapted to vaporise liquid
water in said humidification chamber means in order to provide
water vapour to said gases flow passing through said
humidification chamber means,
gases transportation pathway connected to said outlet of
said humidification chamber means to convey said gases flow
to said patient or other person in need of such gases, and
self-regulating conduit heating means adapted to regulate
the temperature profile of said gases flow along said gases
transportation pathway means and/or of said gases
transportation pathway, to substantially coincide with a
predetermined profile.

ISSUES ON APPEAL
The main issues in this appeal are as follows:
Would a person of ordinary skill in the art have had reason to replace
the heater utilized in the humidification systems of Gradon and Huddart with
a self-regulating PTC heater of the type described in Horsma, Hurko, and
Kamath?

2 Answer mailed Jul. 16, 2007.
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Underlying this issue is the question of whether Horsma, Hurko, and
Kamath, which teach PTC heaters for water heaters and chemical plants, are
in the same field of endeavor as the claimed humidification apparatus and/or
reasonably pertinent to the problem addressed by the inventors.

PRINCIPLES OF LAW
To establish obviousness under 35 U.S.C. § 103, the following factors
must be taken into consideration: (a) the scope and contents of the prior art;
(b) the differences between the prior art and the claimed subject matter; (c)
the level of skill in the pertinent art; and (d) evidence of secondary
considerations. Graham v. John Deere Co., 383 U.S. 1, 17 (1966).
Although § 103 does not define what is meant by “prior art”
this determination is frequently couched in terms of whether the
art is analogous or not, i.e., whether the art is “too remote to be
treated as prior art.” In re Sovish, 769 F.2d 738, 741 (Fed. Cir.
1985).
. . . .
Two criteria have evolved for determining whether prior
art is analogous: (1) whether the art is from the same field of
endeavor, regardless of the problem addressed, and (2) if the
reference is not within the field of the inventor's endeavor,
whether the reference still is reasonably pertinent to the
particular problem with which the inventor is involved. In re
Deminski, 796 F.2d 436, 442 (Fed. Cir. 1986); In re Wood, 599
F.2d 1032, 1036 (CCPA 1979).
In re Clay, 966 F.2d 656, 658-59 (Fed. Cir. 1992).
In making an obviousness determination, “there must be some
articulated reasoning with some rational underpinning to support the legal
conclusion of obviousness.” In re Kahn, 441 F. 3d 977, 988 (Fed. Cir.
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2006); see also KSR Int’l Co. v. Teleflex Inc., 127 S. Ct. 1727, 1740-1741
(2007).
FINDINGS OF FACT
Scope and content of the prior art
Gradon
FF1. It is not disputed that Gradon describes a respiratory humidification
system which comprises a humidification chamber, a chamber heating
means, and a gases transportation pathway that conveys humidified gases to
a patient (App. Br. 15; Gradon, at col. 2, ll. 34-50).
FF2. The gases transportation pathway can comprise a heater wire for
controlling the temperature and humidity of the gas and to reduce
condensation and rainout in the conduit (Gradon, at col. 8, ll. 46-49; at col.
14, ll. 15-33; at col. 17, ll. 55-62). The heat of the wire can be controlled
(id. at col. 14, ll. 14-17).
Huddart
FF3. It is also not disputed that Huddart describes a respiratory
humidification system which comprises a humidification chamber, a
chamber heating means, and a gases transportation pathway that conveys
humidified gases to a patient (App. Br. 15; Huddart, at col. 3, ll. 8-65)
FF4. The gases transportation pathway (inspiratory conduit 11) comprises a
heater wire which can be helically wound around the wall of an inner
conduit (inner conduit 35) (Huddart, at col. 3, l. 61; at col. 3, l. 66 to col. 4, l.
3; at col. 4, ll. 45-50) for heating the gas without condensation (id. at col. 8,
ll. 1-6).

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Horsma
FF5. Horsma teaches that PTC (positive temperature coefficient) heating
elements and PTC strip heaters were known in the prior art (Horsma, at col.
1, l. 9 to col. 3, l. 64). Horsma states that PTC strip heaters had been used in
chemical plants to protect pipes from freezing and to maintain a constant
temperature of liquids flowing in the pipes (id. at col. 3, l. 65 to col. 4, l. 2).
FF6. Horsma describes PTC strip heaters with conductive electrodes which
are braided, serrated, or convoluted (Horsma, at col. 16, ll. 20-25) and with
spaced apart and staggered configurations (id. at col. 22, ll. 45-52). See also
Horsma, Figures 8, 11, and 12 in which elements 20, 22, 32, 34, 37, and 39
are conductive electrodes embedded in PTC material.
Hurko
FF7. Hurko describes a water heater comprising a PTC heating cable with
metal conductors wound around a conduit to maintain the temperature of
water inside it (Hurko, Abstract; at col. 3, ll. 6-26; at col. 4, ll. 41-59). The
heating cable can be looped or spiraled (id. at col. 4, ll. 62-63).
FF8. Figures 3 and 6 of Hurko show the PTC heating cable 68 (with metal
conductors 70 and 72) wrapped around a copper tubing in a spiral or helical
configuration (Hurko, Figures 3 and 6; at col. 4, ll. 52-59).
Kamath
FF9. Kamath states that elongate electrical heaters had been utilized in the
chemical process industry (Kamath, at col. 1, ll. 9-11).
FF10. Kamath describes a self-regulating strip heater which comprises
elongate conductors and a PTC material (Kamath, Abstract).
FF11. The PTC and/or conductors can be arranged in helical or other
configurations (Kamath, at col. 4, ll. 23-35 and 49-52).
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Hirtz
FF12. Hirtz describes a device for treating a patient’s airways with heated
air in which a device with an electric heating unit is connected to a mask
applied to the patient’s face (Hirtz, at 2, ll. 2-6).
FF13. The heater can comprise a PTC heating element (Hirtz, at 3, ll. 1-4)
which is utilized to heat the air to be inhaled by the patient (id. at 4, ll. 11-
26). “The appropriate temperature range for the treatment of the patient’s
airways with heated air can be set simply through appropriate selection of
the [PTC] elements” (id. at 5, ll. 19-21).
Differences between the prior art and the claimed invention
FF14. Claim 1 is directed to a humidification apparatus for providing
humidified air to a patient comprising: a humidification chamber means, a
chamber heating means, a gases transportation pathway, and a self-
regulating conduit heating means to regulate the temperature of gases along
the gases transportation pathway.
FF15. Appellants concede that each of Gradon and Huddart describe a
humidification apparatus with a humidification chamber means, a chamber
heating means, and a gases transportation pathway as in claim 1 (FF1, 3).
FF16. Gradon and Huddart also describe a heater within the gases
transportation pathway (FF2, 4), but as acknowledged by the Examiner,
neither teach that the heater is “self-regulating” as in claim 1 (Ans. 4-5).
Reason to combine the prior art
FF17. Heaters utilizing PTC self-regulation were known in the art for
heating conduits carrying liquid as evidenced by Horsma, Hurko, and
Kamath (see FF5, 7, 10).
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FF18. PTC heaters, as disclosed in Hirtz, had been used to heat air destined
for a patient’s airways (FF12-13).
FF19. Consequently, a person of ordinary skill in the art would have had
reason to replace the heater wire described in the gas transportation pathway
of Gradon and Huddart with a self-regulating PTC heater in order to
eliminate “the need for thermostats and . . . to keep the [conduit] substrate at
a relatively constant desired temperature” (Ans. 5).

Analysis
Claims 1-3 and 10
The difference between the claimed invention and the humidification
systems described in the Gradon and Huddart patents is that the latter do not
describe a self-regulating heater in the transportation pathway which
conveys gases to the patient (FF16). Rather, Gradon and Huddart describe a
heater wire, but do not characterize it as self-regulating. However, self-
regulating PTC heaters were known in the art (FF17) and had been used to
heat gas destined for a patient’s airways (FF18). The Examiner finds, and
we agree, that persons of ordinary skill in the art would have had reason to
replace the heater wire described in the Gradon and Huddart patents with a
self regulating PTC heater for its known advantages (Ans. 5; FF19).
Appellants contend that the Examiner erred in his determination.
Appellants argue that the PTC heaters described in the Horsma, Hurko, and
Kamath patents are for water heaters and industrial chemical applications
and therefore non-analogous prior art improperly combined with Gradon and
Huddart.
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In making an obviousness determination, the first step is to ascertain
the prior art. Graham v. John Deere Co., 383 U.S. at 17. Prior art which is
pertinent to the claimed invention is referred to as “analogous” prior art. It
is well-established that there are two criteria to be applied when determining
whether a prior art reference is analogous: (1) whether the reference is from
the same field of endeavor as the claimed invention, and (2) if the reference
is not within the same field of endeavor, “whether the reference is
reasonably pertinent to the particular problem with which the inventor is
involved.” In re Clay, 966 F.2d at 658-59. When neither criterion is met,
the reference is deemed “non-analogous” and is not considered pertinent to
the § 103 determination.
As to the field of the endeavor, the Examiner contends that the field is
properly defined as “heated conduits” and therefore the Horsma, Hurko, and
Kamath publications are in the same field of endeavor as the claimed
invention. Appellants contend that the endeavor is the transport of
humidified gases to a patient. See App. Br. 21. As each of the three cited
references is engaged in either water heaters or the chemical process
industry, Appellants conclude they are in a different field and therefore non-
analogous.
There are a number of decisions by our reviewing court which refer to
“field of endeavor” as the first factor for determining whether a reference is
analogous art. In In re Wood, 599 F.2d 1032 (CCPA 1979), the court
determined that two references were in the “same field of endeavor” because
they both related to “subsonic variable venturi carburetors.” In re Wood,
599 F.2d at 1036. Similarly, in In re Deminski, 796 F.2d 436 (Fed. Cir.
1986), references teaching compressors with pistons were considered to be
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Application 09/956,723

in the same field as the claimed compressor, even though one reference
(Pocock) involved pumping water out of underground mines and another
involved “use with gas pipelines” (the British patent) because they had
“essentially the same function and structure.” In re Deminski, 796 F.2d at
442. Thus, the court considered prior art to be in the same field of endeavor
as the claimed invention when the prior art described devices with the same
structure (carburetors, compressors) and performed the same function
(pumping). See also In re Bigio, 381 F.3d 1320, 1325 (Fed. Cir. 2004).
In contrast, where the functions were different, even though the
industry was the same, the court found the references non-analogous. See In
re Clay, 966 F.2d 656 (Fed. Cir. 1992), where the court held that although
both references related to the petroleum industry, they were not in the same
field of endeavor because one reference involved storage of “refined liquid
hydrocarbons” while the other involved “the extraction of crude petroleum.”
In re Clay, 966 F.2d at 659.
In this case, we agree with the Examiner’s determination that the cited
Horsma, Hurko, and Kamath are in the same field of endeavor as the
claimed invention because they involve the same general class of devices as
in the claimed invention – conduit heaters – and perform the same heating
function.
Appellants ask us define the field more restrictively to medical
devices for heating humidified gases because the heaters in the three cited
references are used as water heaters and in chemical plants which have
nothing to do with the claimed humidification system. The question comes
down to what level of abstraction is appropriate for choosing a field of
endeavor. Here, it is clear that at the highest level, the claimed medical
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humidification apparatus involves a different industry and different field of
invention than in the Horsma, Hurko, and Kamath publications. However,
the aspect of these prior art references relied upon by the Examiner involves
the same technology – heating conduit pipes. A person designing a heating
system for a medical humidification device would not have been the person
who uses the device, but a technologist familiar with designing conduit
heating systems, the same endeavor as in the Horsma/Hurko/Kamath
disclosures. The analogous prior art under § 103 is therefore what would be
considered relevant by the person who would construct the claimed device.3
In this case, as the person of ordinary skill in the field of the endeavor would
be trained in conduit heating technology, it is logical that she would have
considered heated conduits utilized in water heaters and chemical processing
to be in the same field of endeavor for the purpose of designing a heater for
the gas transportation pathway of the claimed humidification apparatus.
Nonetheless, even were the fields not to be the same, the three
references are “reasonably pertinent” to the problem the claimed invention
attempts to solve. In re Clay, 966 F.2d at 658-59. Both Gradon and
Huddart recognized that the air in the conduit must be heated and maintained
at a particular temperature without producing condensation or rainout (FF2,
4). As found by the Examiner, persons of ordinary skill in the art confronted
with this problem would have looked to known conduit heating devices

3 “Under section 103 we must look to the person of ordinary skill in the art
to which the invention pertains, not those who may use the invention.” In re
Grout, 377 F.2d 1019, 1022 (CCPA 1967) (for the beehive device claimed,
persons of ordinary skill in the art were persons who built beehives, not
beekeepers who used them).
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because they achieve the same purpose of maintaining the contents of the
conduit at a desired temperature (Ans. 5).
Appellants again argue that the Examiner has defined the problem too
broadly. They assert the problem is avoiding rainout (App. Br. 21).
Appellants’ definition is too narrow. According to Clay, 966 F.2d at
658-59, “the purposes of both the invention and the prior art are important in
determining whether the reference is reasonably pertinent to the problem the
invention attempts to solve. If a reference disclosure has the same purpose
as the claimed invention, the reference relates to the same problem.” Here,
the Horsma, Hurko, and Kamath references teach PTC heaters with the same
purpose as the self-regulating heater of claim 1 – to maintain the contents of
the conduit at a desired constant temperature. Thus, under Clay, the cited
references are reasonably pertinent to the inventors’ problem because the
purposes are the same. That the claimed invention also seeks to avoid
condensation in the conduit does not negate the common purpose addressed
by the inventors and the cited Horsma, Hurko, and Kamath references.
Appellants also contend that the cited PTC prior art is non-analogous
because it describes conduits which are heavy, inflexible, and involve
temperatures higher than those that would be safe in a medical application
(see App. Br. 22; Reply Br. 18-19).
These arguments are not persuasive. The obviousness rejection is not
based on utilizing the Horsma/Hurko/Kamath pipes in the Gradon/Huddart
humidification system. Rather, the Examiner found that it would have been
obvious to adapt a PTC heater for use in the gas transportation pathway of
the Gradon/Huddart systems. “Combining the teachings of references does
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not involve an ability to combine their specific structures.” In re Nievelt,
482 F.2d 965, 968 (CCPA 1976) (emphasis in original).
Finally, any argument about the applicability of PTC heaters to the
prior art humidification system is mooted by the express teaching in Hirtz
that PTC heaters can be used to heat air intended for a patient’s airways
(FF12-13). Thus, it would have been reasonably expected that PTC heaters
could be adapted to other systems designed to provide air to a patient and
could operate at safe temperatures.
Appellants also argue that inventive skill would be required to adapt
self regulating conduit heating means to a humidification apparatus (App.
Br. 28-32.) The arguments rely again on the purported weight and
inflexibility of the Horsma/Hurko/Kamath pipes. Neither weight nor
flexibility is a limitation in the claims (Ans. 3), but in any case references
need not be capable of physical combination to show obviousness. In re
Etter, 756 F.2d 852, 859 (Fed. Cir. 1985) (in banc). Hirtz expressly taught
that PTC elements for patient airway humidification could be selected by
those of skill in the art (FF13) Hirtz supports the Examiner’s conclusion of
obviousness.

Claims 4, 5, and 11
Claim 4 is directed to the humidification apparatus of claim 1 in
which the “regulated conduit heating means comprises at least a portion of
the wall of said gases transportation pathway formed of a” PTC material.
Claim 5 depends on claim 4 and further recites that “the entire wall of said
gases transportation pathway includes at least a layer of said” PTC material.
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Appellants contend that none of Horsma, Hurko, or Kamath describes
a conduit formed at least partially from PTC material (App. Br. 32).
This argument is not persuasive. The Examiner cited Huddart for
teaching a heater element incorporated into a conduit wall (Ans. 5; FF4).
Appellants have not identified a deficiency in the Examiner’s findings.

Claims 6 and 7
Claim 6 is to a humidification apparatus in which the electrical
conductors “are disposed helically within” the wall of the gases
transportation pathway. Claim 7 depends on claim 6 and further requires
that the conductors are “substantially evenly spaced from another over their
entire length.” Appellants contend that such limitations are not described in
the prior art.
Each of Hurko and Kamath describe PTC heaters with conductors
arranged in a helical configuration (FF8, 11). According to Horsma, the
conductors can be spaced apart (FF6). Thus, the limitations recited in claims
6 and 7 are described in the prior art.

Claims 8 and 9
Claim 8 depends on claim 5 and adds the limitation that the gases
transportation pathway includes spaced apart conductors which comprise
helically arranged PTC ribbons. Claim 9 depends on claim 8 and further
requires “at least two electrical conductors [which] run longitudinally within
said ribbon of positive temperature coefficient material, and each of said
conductors is electrically connected with said ribbon.”
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Appellants contend that the prior art does not “suggest techniques for
manufacturing a conduit that includes at least a layer of PTC material” (App.
Br. 35).
This argument is not persuasive. As stated above, the Examiner cited
Huddart for teaching a heater element incorporated into a conduit wall (Ans.
5; FF4). Appellants have not identified a deficiency in the Examiner’s
findings.

Claims 12 and 13
Claims 12 and 13 recite specific phase transformation temperatures
for the PTC material. The Examiner finds the recited temperatures would
have been obvious to persons of ordinary skill in the art (Ans. 5).
Appellants contend that none of Horsma, Hurko, or Kamath “disclose or
discuss varying the composition of the PTC material to alter or ‘tune’ its
properties” (App. Br. 36).
This argument is not persuasive. Hirtz teaches selecting PTC material
to achieve the “appropriate temperature range for the treatment of the
patient’s airways with heated air” (Hirtz, at 5, ll. 19-21; FF13). Thus, Hirtz,
in fact, describes selecting a PTC material to “tune” its properties to a
desired temperature.

CONCLUSIONS OF LAW
The teachings of Horsma, Hurko, and Kamath are in the same field of
endeavor as the claimed humidification apparatus and also reasonably
pertinent to the problem addressed by the inventors. The Examiner therefore
properly combined their teachings with those of Gradon and Huddart. Based
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on the cited prior art, persons of ordinary skill in the art would have had
reason to replace the heater utilized in the humidification system of Gradon
and Huddart with a self-regulating PTC heater of the type described in
Horsma, Hurko, and Kamath. Therefore, we affirm the rejection of claim 1
as obvious over the combined teachings of Gradon, Huddart, Hirtz, and
Horsma, Hurko, or Kamath. Claims 2, 3, 10 depend on claim 1 and
incorporate all its limitations. As these claims were not separately argued,
they fall with claim 1. 37 C.F.R. § 41.37(c)(1)(vii).
We affirm the rejections 4-9, 12, and 13 as the limitations in these
claims are either taught or suggested by the cited prior art. Claim 11 was not
separately argued and therefore falls with claim 4 upon which it depends. 37
C.F.R. § 41.37(c)(1)(vii).
TIME PERIOD
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a).

AFFIRMED

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