Ex Parte Patel et al

Patent Trial and Appeal Board

Aug 6, 2018

13091705 (P.T.A.B. Aug. 6, 2018)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE
13/091,705 04/21/2011
88326 7590
Kinney & Lange, P.A.
312 South Third Street
Minneapolis, MN 55415
08/08/2018
FIRST NAMED INVENTOR
Tejendra Patel
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
ATTORNEY DOCKET NO. CONFIRMATION NO.
58299US01-U74-012265 5131
EXAMINER
COMINGS, DANIEL C
ART UNIT PAPER NUMBER
3744
NOTIFICATION DATE DELIVERY MODE
08/08/2018 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):
USPatDocket@kinney.com
amkoenck@kinney.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte TEJENDRA PATEL, JEFFREY ERNST,
BRUCE R. SCHRODER, ROBERT M. DEROY, and
KODJOVI COUSSEY
Appeal2017-009851
Application 13/091,705 1
Technology Center 3700
Before LINDA E. HORNER, EDWARD A. BROWN, and
JEREMY M. PLENZLER, Administrative Patent Judges.
HORNER, Administrative Patent Judge.
DECISION ON APPEAL
STATEMENT OF THE CASE
Appellants seek our review under 35 U.S.C. § 134(a) of the
Examiner's decision rejecting claims 1-23. Final Office Action (December
22, 2015) (hereinafter "Final Act."). We have jurisdiction under 35 U.S.C.
§ 6(b).
1 Tejendra Patel et al. ("Appellants") identify Hamilton Sundstrand
Corporation as the real party in interest. Appeal Brief (May 20, 2016)
(hereinafter "Br."), at 2.
Appeal2017-009851
Application 13/091,705
The claimed subject matter relates to "control algorithms used to
regulate the position of the [ electronic expansion valves]" in refrigeration
systems. Specification (April 21, 2011) (hereinafter "Spec."), ,r 1. The
Examiner rejected the claims as obvious over the prior art. For the reasons
explained below, we find error in the Examiner's rejections. Accordingly,
we REVERSE.
CLAIMED SUBJECT MATTER
Claims 1, 10, and 17 are the independent claims on appeal. Claim 1 is
illustrative of the claimed subject matter and is reproduced below with
disputed limitations italicized for emphasis.
1. A method of controlling position of an electronic
expansion valve (EEV) employed in a refrigeration system, the
method comprising:
generating, by a processing unit, a first EEV position
control signal based on superheat feedback associated with the
refrigeration system in a first control loop;
generating, by the processing unit, a second EEV position
control signal based on pressure feedback associated with the
refrigeration system in a second control loop;
comparing, by the processing unit, the first EEV position
control signal and the second EEV position control signal;
selecting, by the processing unit based on the comparison
of the first EEV position control signal and the second EEV
position control signal, either the first EEV position control
signal or the second EEV position control signal as a selected
position control signal employed to control position of the EEV;
providing, by the processing unit, the selected position
control signal in feedback to both the first control loop and the
second control loop;
outputting, by the processing unit, the selected position
control signal to modify a position of the EEV; and
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Application 13/091,705
modifying, based on the outputted selected position
control signal, the position of the EEV.
Br. 15 (Claims Appendix).
Nickell
Tenedini
McCulloch
Jessen
McCormick
Koehl
Kawakatsu
EVIDENCE
us 4,069,030
us 4,547,977
us 4,689,968
US 2004/0068999 Al
US 2006/0059926 Al
US 7,612,510 B2
US 2010/0064723 Al
REJECTIONS
Jan. 17, 1978
Oct. 22, 1985
Sept. 1, 1987
Apr. 15, 2004
Mar. 23, 2006
Nov. 3, 2009
Mar. 18, 2010
The Final Office Action includes the following rejections under
pre-AIA 35 U.S.C. § I03(a):
1. Claims 1, 2, 9-11, 16-18, and 21-23 stand rejected as unpatentable
over Kawakatsu, McCormick, and Nickell.
2. Claims 3, 4, 6, 12, 14, and 20 stand rejected as unpatentable over
Kawakatsu, McCormick, Nickell, Jessen, and McCulloch.
3. Claims 5 and 13 stand rejected as unpatentable over Kawakatsu,
McCormick, Nickell, Jessen, McCulloch, and Tenedini.
4. Claims 7, 8, and 15 stand rejected as unpatentable over Kawakatsu,
McCormick, Nickell, and Koehl.
5. Claim 19 stands rejected as unpatentable over Kawakatsu,
McCormick, Nickell, and Tenedini.
ANALYSIS
In the rejection of independent claim 1, the Examiner found that
Kawakatsu teaches a method of controlling the position of an EEV,
including generating a first EEV position control signal ( either S6 or S8) and
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Application 13/091,705
generating a second EEV position control signal ( either S2 or S4 ). Final
Act. 3 ( citing Kawakatsu, Fig. 2). The Examiner also found that the method
of Kawakatsu includes selecting either the first or the second EEV position
control signal as the selected position control signal. Id. at 3-4. The
Examiner found that Kawakatsu does not disclose comparing these two
signals to each other for selecting the signal to be used in controlling the
position of the EEV. Id. at 4. The Examiner relied on Nickell to teach a
controller for a refrigeration cycle system in which a pair of control signals
are compared to each other and the output of the comparison is used in the
control of a valve of the system. Id. The Examiner determined that it would
have been obvious "to modify Kawakatsu with the signal comparison
control of Nickell in order to more directly achieve [] a control scheme such
as that taught by Kawakatsu through direct comparison of the signals to one
another in order to provide a less complex and thus more robust control
system." Id. at 4-5. The Examiner relied on these same findings and
reasoning as the basis for the rejection of independent claims 10 and 17. Id.
at 6. 2
Appellants argue that the Examiner erred in rejecting the claims
because Nickell does not disclose comparing control signals, and because
the Examiner failed to articulate adequate reasoning based on rational
underpinnings for the proposed modification of Kawakatsu with the teaching
of Nickell. Br. 7-11. As to the former, Appellants assert that "Nickell
2 The Examiner's finding as to the disclosure of McCormick and the
proposed modification of Kawakatsu with McCormick are not at issue in this
appeal. Final Act. 4 (Examiner finding McCormick teaches valve position
feedback), Br. 11-12 (Appellants not contesting this finding as to
McCormick).
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Application 13/091,705
discloses a system in which measured pressure signals corresponding to
outside air enthalpy and return air enthalpy can be compared by a
differential pressure switch to activate an air solenoid valve for operation of
a cooling system." Id. at 7. As to the latter, Appellants assert that
"Kawakatsu merely discloses a series of threshold checks that can be utilized
to control the opening and closing of the electronic expansion valve."
Br. 10. According to Appellants, "Kawakatsu illustrates and describes that
each threshold check that results in a control command bypasses each
of the other threshold checks. As such, Kawakatsu discloses the
generation of, at most, one command configured to control the electronic
expansion valve during any given execution of the operations of FIG. 2." Id.
Thus, Appellants contend that the art relied on by the Examiner does not
suggest why a comparison of the control commands in Kawakatsu would
"more directly achieve the control scheme as that taught by Kawakatsu" or
"provide a less complex and thus more robust control system" as asserted by
the Examiner. Id. at 11.
We agree with Appellants on both counts. First, Nickell does not
disclose comparing control signals. We look to Appellants' Specification
for a discussion of the claimed control signals. The Specification describes
two control loops 40, 42, which receive as inputs monitored temperature
and/or monitored pressure of the refrigerant output from the evaporator.
Spec. ,r 15. In each control loop, the input temperature and/or pressure is
provided to a calculator that calculates a value based on these inputs and/ or
compares the value to a desired value to calculate an error based on the
difference between the calculated and the desired values. Id. ,r,r 15-17. The
calculated error is provided to a PI control block, which determines a step
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output that represents the desired position of the EEV. Id. ,r,r 16-17. This
step output value is output by the PI control block as a position control
signal. Thus, the position control signals compared in selector block 54 are
the step output signals generated by the PI control block. Id.
By contrast, in Nickell, measurements of enthalpy, represented using
pressure, are sent from return air transmitter 46 and outside air transmitter 51
to differential pressure switch 48 to select a source of air to use in the air
conditioner. Nickell, col. 5, 11. 15-27. The pressures compared in Nickell's
differential pressure switch are not control signals. Rather, the inputs to
Nickell' s differential pressure switch are enthalpy measurements, akin to
temperature and pressure measurements input into the control loops of
Appellants' invention.
Second, the Examiner's articulated reasoning for modifying
Kawakatsu in the manner claimed lacks rational underpinnings. Kawakatsu
discloses a refrigeration system for a marine container that uses either a
water-cooled condenser or an air-cooled condenser as a cold heat source to
condense refrigerant. Kawakatsu ,r 1. Kawakatsu explains that the amount
of refrigerant the refrigerant circuit requires generally is less in the water-
cooled operation mode than in the air-cooled operation mode. Id. ,r 6.
Kawakatsu's method avoids the possibility of a high-pressure condition
developing due to surplus refrigerant accumulated in the water-cooled
condenser when the system is in the water-cooled operation mode. Id. In
particular, Kawakatsu describes using the degree of superheat of the
evaporator to control the degree of opening of the EEV, except in the case
where the high pressure abnormally increases during the water-cooled
operation mode. Id. ,r 7. In such an instance, the degree of opening of the
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EEV is forcibly decreased to reduce the refrigerant circulation amount to
prevent an increase in the high pressure of the refrigerant circuit. Id.; see
also id. ,r 12. Thus, in Kawakatsu's method, the high-pressure condition
overrides the normal control of the EEV based on the superheat condition, as
shown in the flowchart of Figure 2 of Kawakatsu. See also id. ,r,r 55-56
( describing Fig. 2). In other words, in Kawakatsu, if the high pressure
detected by the high-pressure sensor exceeds a specified pressure threshold,
then a control command is sent to the EEV to forcibly decrease the degree of
opening of the EEV, and the system bypasses steps S5-S8, which check the
degree of superheat. Id. Thus, as argued by Appellants, in Kawakatsu's
method, each threshold check that results in a control command bypasses
each of the other threshold checks. Kawakatsu, Fig. 2.
The Examiner has failed to explain adequately why one having
ordinary skill in the art would recognize an improvement to Kawakatsu's
method by comparing the high-pressure condition signals with the superheat
condition signals. Specifically, we do not see how directly comparing these
two signals would result in a "less complex" and "more robust control
system" as asserted by the Examiner.
Further, the Examiner has not explained adequately how the teachings
of Nickell would have led one to make the proposed modification. As
discussed briefly above, Nickell relates to a control system for an air
conditioner that compares measurements of enthalpy in the outside air and
enthalpy in the return air to determine which source of air to use in the air
conditioner to consume the least amount of energy. Nickell, col. 3, 11. 8-29.
Nickell' s system improves the prior art by providing sensing units capable of
reliably measuring the wet bulb temperature of each air source to provide an
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Application 13/091,705
accurate calculation of enthalpy. Id. at col. 4, 11. 55-57. It is not readily
apparent, and the Examiner has not sufficiently explained, how Nickell's
teaching of comparing measurements representing enthalpy of different air
sources, would have led one having ordinary skill in the art to modify
Kawakatsu's method to compare signals representative of a high-pressure
condition and signals representative of a superheat condition to control an
EEV. In other words, the Examiner has not explained why a skilled artisan
would have been led to compare Kawakatsu's signals, as opposed to using
the high-pressure condition as the overriding control condition.
For these reasons, we do not sustain the rejection of independent
claims 1, 10, and 17, and their dependent claims 2, 9, 11, 16, 18, and 21-23,
as unpatentable over Kawakatsu, McCormick, and Nickell. The remaining
grounds of rejection of dependent claims 3-8, 12-15, 19, and 20, also rely
on the above-noted deficiencies in the rejection of the independent claims
based on Kawakatsu as modified by Nickell. As such, we also do not
sustain rejections of these dependent claims.
DECISION
The decision of the Examiner rejecting claims 1-23 is reversed.
REVERSED
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