Chemco Systems, L.p. v. Rdp Technologies, Inc.

N OTE: This disposition is nonprecedential.
United States Court of Appeals
for the Federal Circuit
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CHEMCO SYSTEMS, L.P.,
Appellant
v.
RDP TECHNOLOGIES, INC.,
Appellee
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2022-1459
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Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in No. IPR2019-
01564.
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Decided: March 10, 2023
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J ENNIFER L. SWIZE, Jones Day, Washington, DC, for ap-
pellant. Also represented by MARLEE HARTENSTEIN,
MATTHEW J OHNSON, Pittsburgh, PA.
T HOMAS F ISHER, Cozen O'Connor P.C., Washington,
DC, for appellee. Also represented by K ERI SCHAUBERT ,
New York, NY.
______________________
Case: 22-1459 Document: 46 Page: 1 Filed: 03/10/2023

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CHEMCO SYSTEMS, L. P. v. RDP TECHNOLOGIES, INC. 2
Before M OORE, Chief Judge, P ROST and STARK, Circuit
Judges.
P ROST , Circuit Judge.
Chemco Systems, L.P. (“Chemco”) petitioned for inter
partes review of claims 1 and 2 of U.S. Patent
No. 7,416,673 (“the ʼ673 patent”) owned by appellee RDP
Technologies, Inc. In a final written decision, the Patent
Trial and Appeal Board (“Board”) determined Chemco had
not shown these claims were unpatentable as obvious. The
Board denied Chemco’s rehearing request. Chemco ap-
peals. We affirm.
The ʼ673 patent generally relates to a lime slurry recir-
culation loop for the removal of unwanted grit particles and
the extraction of lime slurry. The only issue on appeal is
whether substantial evidence supports the Board’s find-
ings that two asserted prior art references do not teach or
suggest a “suction line” for extraction.
Before the Board, Chemco argued that U.S. Patent
No. 5,336,481 (“Muzik”) disclosed all elements of claims 1
and 2 apart from an element requiring the extraction of
slurry “via a suction line, through a stilling well, that al-
lows gravity separation of grit from slurry.” ’673 patent
claim 1. Chemco argued that either U.S. Patent No.
6,833,078 (“Espinoza”) or U.S. Patent No. 6,197,190
(“Hanlon”) discloses or renders obvious that element—and
that, further, a person of ordinary skill in the art would
have combined Muzik’s slurry loop with the stilling well
disclosed in those references. Chemco thus argued that the
challenged claims were unpatentable as obvious over (1)
Muzik in view of Espinoza or (2) Muzik in view of Hanlon.
The Board rejected Chemco’s argument. In its final
written decision, the Board found that neither Espinoza
nor Hanlon discloses or renders obvious the required suc-
tion line. Since Chemco relied only on Espinoza or Hanlon
Case: 22-1459 Document: 46 Page: 2 Filed: 03/10/2023

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CHEMCO SYSTEMS, L. P. v. RDP TECHNOLOGIES, INC. 3
to teach the suction line, the Board concluded that Chemco
had not shown claims 1 and 2 unpatentable as obvious.
Obviousness is a legal question based on underlying
findings of fact. Am. Nat’l Mfg. Inc. v. Sleep No. Corp., 52
F.4th 1371, 1379 (Fed. Cir. 2022). We review the Board’s
legal conclusions de novo and its factual findings for sub-
stantial evidence. Id.
The Board’s finding that neither Espinoza nor Hanlon
discloses a suction line is supported by substantial evi-
dence. Chemco admits that neither reference explicitly
mentions extraction of slurry via a suction line. Appel-
lant’s Br. 14. And its arguments that the references im-
plicitly indicate suction or that they render use of suction
obvious are unpersuasive.
As the Board found, the apparatus disclosed in Espi-
noza does not include a pump to create suction. J.A. 30–
31. Instead, the placement of outlet line 210 below the
chamber’s fluid line permits removal via gravity flow. J.A.
30. Given this placement, the reference to “drawing off” a
particle-rich stream from the top of the settling chamber in
Espinoza does not have the same meaning as the ʼ673 pa-
tent’s reference to “drawing off” via a suction line. J.A. 30–
31. Similarly, Hanlon does not teach a suction line or a
pump. J.A. 35. And the Board found that Chemco did not
sufficiently explain why a person of ordinary skill in the art
would have chosen suction over Hanlon’s collecting pipe 26.
J.A. 35; see also J.A. 45. We conclude that substantial evi-
dence supports these findings.
We have considered Chemco’s remaining arguments
and find them unpersuasive. For the foregoing reasons, we
affirm the Board’s decision.
AFFIRMED
Case: 22-1459 Document: 46 Page: 3 Filed: 03/10/2023

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