Honeywell International Inc.

Patent Trials and Appeals Board

Dec 16, 2020

2020001275 (P.T.A.B. Dec. 16, 2020)

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.
15/088,637 04/01/2016 Andrew J. Milley H0049148-US (696751) 3612
119991 7590 12/16/2020
HONEYWELL/ALSTON-SCANNING & MOBILITY
Intellectual Property Services Group
300 S. Tryon Street
Suite 600
Charlotte, NC 28202
EXAMINER
OLAMIT, JUSTIN N
ART UNIT PAPER NUMBER
2853
NOTIFICATION DATE DELIVERY MODE
12/16/2020 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):
SPSIP@honeywell.com
patentservices-us@honeywell.com
usptomail@alston.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte ANDREW J. MILLEY
____________

Appeal 2020-001275
Application 15/088,637
Technology Center 2800
____________

Before LINDA M. GAUDETTE, MICHAEL P. COLAIANNI, and
MERRELL C. CASHION, JR., Administrative Patent Judges.

CASHION, Administrative Patent Judge.

DECISION ON APPEAL

STATEMENT OF THE CASE

Pursuant to 35 U.S.C. § 134(a), Appellant1 appeals from the
Examiner’s decision to reject claims 1–6, which constitute all the claims
pending in this application. We have jurisdiction under 35 U.S.C. § 6(b).
We AFFIRM.

1 We use the word “Appellant” to refer to “applicant” as defined in
37 C.F.R. § 1.42. Appellant identifies Honeywell International Inc., as the
real party in interest. Appeal Br. 3.
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Application 15/088,637

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The invention “relates generally to sensors, and more particularly, to
flow sensors that are configured to sense the flow of a fluid in a flow
channel.” Spec. 1. Claim 1 illustrates the invention:
1. A flow sensor for sensing a fluid flow rate through
a flow channel, the flow sensor comprising:
an upstream resistive element having a first resistance
that changes with temperature and having a first temperature
coefficient of resistance (TCR);
a downstream resistive element having a second
resistance that changes with temperature and having a second
TCR, wherein the downstream resistive element is situated
downstream of the upstream resistive element in the flow
channel and wherein the first TCR and the second TCR are
substantially the same;
the upstream resistive element and the downstream
resistive element are operatively connected in a bridge circuit,
wherein the bridge circuit is configured to supply a current to
each of the upstream resistive element and the downstream
resistive element,
wherein the current causes resistive heating in both the
upstream resistive element and the downstream resistive
element such that both the upstream resistive element and the
downstream resistive element are heated above the ambient
temperature of the fluid flowing through the flow channel,
wherein the fluid flow through the flow channel caus[es]
the temperature of the upstream resistive element to be lower
than the temperature of the downstream resistive element,
wherein a difference in temperature between the
upstream resistive element and the downstream resistive
element causes an imbalance in the bridge circuit that is related
to the fluid flow rate of the fluid flowing though the flow
channel;
a low TCR resistor connected in series with the bridge
circuit, the low TCR resistor having a third TCR that is at least
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Application 15/088,637

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an order of magnitude lower than the first TCR and at least an
order of magnitude lower than the second TCR;
wherein the upstream resistive element and the
downstream resistive element are each configured to sense a
temperature of the fluid and heat the fluid; and
a slit extending transversely through the flow sensor
between the upstream resistive element and the downstream
resistive element, wherein at least one of the upstream resistive
element and the downstream resistive element is situated next
to the slit.
Appellant requests review of the following rejections from the
Examiner’s Final Office Action, dated January 31, 2019:
I. Claims 1–5 rejected under 35 U.S.C. § 103 as unpatentable over
Azumi (US 6,250,150 B1, issued June 26, 2001), the AAPA (Applicant's
Admitted Prior Art),2 and Wang (US 8,356,514 B2, issued January 22,
2013).

II. Claim 6 rejected under 35 U.S.C. § 103 as unpatentable over
Azumi, AAPA, Wang, and Kanazawa (US 4,510,813, issues April 16,
1985).

For Rejection I, Appellant presents arguments only for independent
claim 1 and does not present substantive arguments for dependent claims
2–5. See generally Appeal Br. In addition, Appellant relies on the
arguments presented for claim 1 to address the separate rejection of claim 6
(Rejection II). See id. Accordingly, we select claim 1 as representative of
the subject matter claimed and decide the appeal as to all grounds of
rejection based on the arguments Appellant makes in support of the
patentability of claim 1.

2 The Examiner relies on Application Figure 2 and the accompanying
description on pages 3–5 of the Specification as the AAPA. Final Act. 4–5.
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OPINION
After review of the respective positions the Appellant provides in the
Appeal and Reply Briefs and the Examiner provides in the Final Action and
the Answer, we affirm the Examiner’s prior art rejections of claims 1–6
based on the fact-finding and the reasons the Examiner provides. We add
the following for emphasis.
Independent claim 1
Claim 1 recites a flow sensor comprising upstream and downstream
resistive elements operatively connected in a bridge circuit, where the bridge
circuit is configured to supply a current to the upstream and downstream
resistive elements. Claim 1 also recites the flow sensor as having a low
TCR3 resistor connected in series with the bridge circuit.
The Examiner finds that Azumi teaches a flow sensor comprising
upstream and downstream resistive elements connected to a predetermined
circuit that differs from the subject matter of claim 1 in that Azumi (1) does
not disclose the predetermined circuit to be a bridge circuit and (2) does not
teach the use of a low TCR resistor connected in series with the bridge
circuit. Final Act. 3–4.
Regarding difference (1), the Examiner finds that the AAPA, as
shown in Application Figure 2, discloses that it is known in the art to use a
bridge circuit to connect upstream and downstream resistive elements of a
flow sensor for operation so the resistive elements can provide a flow sensor
output signal. Final Act. 4–5; Spec. 4. The Examiner determines that it

3 TCR stands for “temperature coefficient of resistance.”
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would have been obvious to one of ordinary skill in the art to modify
Azumi’s flow sensor by replacing Azumi’s predetermined circuit with a
well-known bridge circuit to connect Azumi’s upstream and downstream
resistive elements with a reasonable expectation that Azumi’s modified flow
sensor would provide the desired flow sensor output signal. Final Act. 5.
Regarding difference (2), the Examiner finds that AAPA’s
Application Figure 2 teaches that it is known to have a resistor (R1)
connected in series with a bridge circuit. Final Act. 6; see also Spec. 4.
While AAPA does not disclose the TCR characteristic of this resistor, the
Examiner finds that AAPA’s resistor R1 is not used to measure the
temperature of the fluid. Final Act. 5. The Examiner finds that Wang uses
low to zero TCR resistors as heater resistors, which are also not used to
measure the temperature of a fluid. Final Act. 3; Wang col. 4, ll. 19–35.
The Examiner finds that Wang teaches that low to zero TCR values increase
the thermal stability and reliability of a resistor. Final Act. 6; Wang col. 4,
11. 61–63. From this disclosure, the Examiner finds that Wang suggests low
to zero TCR resistors as useful resistors when not used to measure the
temperature of a fluid. Final Act. 6. The Examiner determines that it would
have been obvious for one having ordinary skill in the art to use a low TCR
resistor as the AAPA’s R1 resistor in the flow sensor from the combined
teachings of the cited art in view of Wang’s teachings. Id.
With respect to difference (1), Appellant argues that one skilled in the
art would not use a bridge circuit in Azumi’s flow sensor because the AAPA
teaches using a separate heater resistor Rh to heat the fluid in the flow
channel that evenly heats the bridge circuit’s resistive elements RU1, RU2,
RD1 and RD2. Appeal Br. 7. According to Appellant, the AAPA
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arrangement does not use the bridge circuit’s resistive elements to heat the
fluid in the flow sensor’s channel. Id. at 7–8. Appellant argues that the
AAPA does not disclose a bridge circuit that supplies current to each of the
upstream resistive element and the downstream resistive element to cause
resistive heating in both the upstream and downstream resistive elements
above the ambient temperature because the AAPA teaches to use separate
heater resistor Rh and heater control circuit 206 for this purpose. Id. at 9.
Thus, Appellant contends that substituting Azumi’s predetermined circuit
with the AAPA’s bridge circuit would necessarily include the heater resistor
Rh and the heater control circuit 206. Id.
Appellant’s arguments do not identify reversible error in the
Examiner’s determination of obviousness for the reasons the Examiner
presents. The premise of Appellant’s arguments is that the AAPA’s bridge
circuit requires the use of a heater resistor to provide the temperature
difference that will result in a flow sensor output signal. However, as the
Examiner explains, Azumi discloses fluid sensor embodiments that comprise
a resistor heater and others that do not. Final Act. 4; Azumi Figures 2 and
14, col. 1, l. 61– col. 2, l. 16, col. 9, ll. 19–24. Thus, Azumi discloses that
the heater resistor is a separate component that is not tied to any particular
circuit and an optional component for a flow sensor. Given that Azumi
teaches embodiments that, like Appellant’s invention, use the resistive
elements without a heater resistor to “heat the heating elements themselves
and heat fluid, respectively, and, also, [] . . . detect[] the velocity of flow of
the fluid” (Azumi col. 9, ll. 19–24), Appellant has not explained adequately
why one skilled in the art, using no more than ordinary creativity, would not
have been capable of modifying Azumi’s flow sensor by substituting
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Azumi’s predetermined circuit with a well-known bridge circuit, as the
AAPA teaches, to supply Azumi’s resistive elements with the requisite
current and reasonably expect that such an arrangement would still result in
a difference in temperature between the upstream resistive element and the
downstream resistive element that causes an imbalance in the bridge circuit
that is related to the fluid flow rate of the fluid flowing though the flow
channel. See KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 421 (2007) (“A
person of ordinary skill is also a person of ordinary creativity, not an
automaton.”); see also In re Sovish, 769 F.2d 738, 743 (Fed. Cir. 1985)
(presuming skill on the part of one of ordinary skill in the art).
With respect to difference (2), Appellant argues that Wang does not
teach a low TCR heater resistor connected in series with a bridge circuit, as
recited in claim 1. Appeal Br. 9.
Appellant’s arguments are not persuasive of reversible error in the
Examiner’s determination of obviousness for the reasons the Examiner
presents.
Appellant’s arguments do not address the rejection the Examiner
presents. As the Examiner explains, Wang is merely used to modify the
temperature coefficient of resistance (TCR) of the resistor to be low (thus
having a TCR lower than that of the other resistive elements) to promote
thermal stability and reliability (Wang: col. 4, lines 61–63) of the resistor.
Ans. 6; Wang col. 4, ll. 61–63.
Moreover, as the Examiner notes, the AAPA teaches the structure of a
bridge circuit having a resistor connected in series. Final Act. 6. The
Examiner’s rejection seeks to make this resistor, and not a heater resistor, a
low TCR resistor for the advantages of that type of resistor that Wang
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teaches. Appellant has not refuted this determination convincingly in the
Appeal or Reply Briefs.
Accordingly, we affirm the Examiner’s prior art rejections of claims
1–6 for the reasons the Examiner presents and we give above.

DECISION SUMMARY

In summary:

Claims
Rejected
35 U.S.C.
§
Reference(s)/Basis Affirmed Reversed
1–5 103 Azumi,
Appellant’s
Admitted Prior Art
(AAPA), Wang
1–5
6 103 Azumi,
Appellant’s
Admitted Prior Art
(AAPA), Wang,
Kanazawa
6
Overall
Outcome
1–6

No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a)(1)(iv).

AFFIRMED