Product-by-Process Claim: The Focus is On the Product and Not the Process of Making It

September 6, 2022

Kamstrup A/S appealed a final written decision of the Patent Trial and Appeal Board (“the Board”). The Board found claims 1–15 of Kamstrup’s U.S. Patent No. 8,806,957 unpatentable as obvious or anticipated. On appeal, Kamstrup challenged the Board’s claim constructions. In addition, Kamstrup challenged the Board’s anticipation and obviousness determinations largely on the basis that the Board erred in rejecting Kamstrup’s claim construction arguments.

Kamstrup owns the ’957 patent” directed to “an ultrasonic flow meter housing in the form of a monolithic polymer structure being cast in one piece.” It explains that “the present invention can be fabricated with a reduced number of steps compared to existing meters, since only a single step is used to form the monolithic polymer structure.”

On September 23, 2019, Axioma petitioned for inter partes review of all 15 claims of the ’957 patent. In its final written decision, the Board found the challenged claims unpatentable as obvious or anticipated. Axioma Metering UAB v. Kamstrup A/S, No. IPR2019-01640, 2021 WL 1235790 (P.T.A.B. Apr. 1, 2021). In reaching its final determination, the Board construed elements of the claims “cast in one piece” as a product-by-process claim element and also construed the phrase “cavity separated from the flow tube.” The Board explained that the claim language described the process of “casting” the polymer housing and did not describe the housing’s structure. After construing the claim element, the Board concluded that it did not impart patentable weight to the claims and thus should not be considered as part of any anticipation or obviousness analysis. The Board explained that Kamstrup did not present any evidence showing that the claim element provided structural and functional differences distinguishing it from the prior art. Thus, the Board concluded that the claim element was not entitled to patentable weight.

Next, the Board explained that Ueki (EP1482284 A1) disclosed the “cavity separated from flow tube” limitation. The Board found the limitation disclosed because Ueki’s through water pipe line ran through a circuit/sensor housing area and was separated from the circuit/sensor housing area by the outer surface of the through water pipe line. Finally, the Board found that Ueki disclosed the remaining limitations of claims 1 and 11. The Board also relied on Ueki as the primary reference in combination with US 6,248,077 (“Elson”) and/or US 4,476,877 (“Barker”) to find the remaining claims obvious.

The Board made an initial finding that Elson and Barker were analogous art to the ’957 patent, rejecting Kamstrup’s argument to the contrary. The Board explained that the references were at least in the same field of endeavor as the ’957 patent because they were directed to fluid flow and fluid flow characteristics. Additionally, the Board found that Elson and/or Barker disclosed the claim scope introduced in claims 6 and 8. Kamstrup argued that Elson and Barker did not disclose the “measurement tube element” of claim 6 because the limitation was restricted to elements measuring flow, whereas Elson and Barker disclosed other types of sensors. The Board rejected this argument, explaining that the ’957 patent did not limit the measurement tube element to a particular type of sensor. Kamstrup also argued that Elson and Barker did not disclose the protrusions or indentions that claim 6 required, and that the protrusions or indentions must be on or part of the flow section wall and integral with the wall’s inside surface.

The Board disagreed, explaining that, according to the plain language of claim 6, the limitations were satisfied if the protrusions or indentions were within the bounds of the flow section and could engage with the measurement tube element. The Board found that Elson disclosed a receiver (a protrusion) attached to a tube section (a flow tube) and also explained that the receiver was located inside the tube section and accommodated a probe (a measurement tube element). Finally, the Board found that a person of ordinary skill in the art would have been motivated to modify Ueki with Elson and/or Barker. Specifically, the Board credited Axioma’s expert testimony that it was common to measure temperature when measuring flow. Kamstrup appealed the Board’s claim constructions and patentability determinations.

On appeal, Kamstrup argued that the Board erred in construing “cast in one piece” as a product-by-process claim element. However, the Court of Appeals for the Federal Circuit (“the Court”) determined that the claim language confirmed that the claim was a product-by-process claim. Thus, on its face, the claim element (“a monolithic polymer structure being cast in one piece”) recites a process because it describes the structure “being” cast in a particular way.

Kamstrup argues that “[t]he mere mention of a process in a claim limitation does not automatically convert that limitation into a process limitation.” The Court replied that while that might be true, Kamstrup did not explain “why we should disregard the fact that the claims recite a process here. Nor does Kamstrup point to disclosure in the specification that describes structure for the term. Instead, Kamstrup relies on disclosure discussing the fabrication process for the device — further support that this is a product-by-process claim element.” The Court concluded that the Board did not err in finding that “cast in one piece” was a product-by-process claim element.

The second question considered by the Court was whether the product-by-process claim element imparted patentable weight to the claims. The Court concluded that it did not. Kamstrup argued that the Board erred in finding that there were no functional or structural differences between polymer structures cast in a single mold versus multiple molds. Kamstrup stated that “various structures . . . cannot be cast in a single mold using conventional die cast injection molding technologies.” However, according to the Court, “even if it is true, Kamstrup had not identified functional and structural differences between a structure “cast in one piece” and a structure manufactured using another method. Rather, Kamstrup merely argued that the claim element described a manufacturing method with some inherent restrictions and had not identified any disclosure in the specification or prosecution history or extrinsic evidence evidencing structural and functional differences.” The Court pointed out that the alleged structural and functional difference that Kamstrup identified was detached from the claims, as the claims stated that the structure should be “cast in one piece,” not cast in one mold. The Court agreed with the Board’s correct founding that the written description “focuses on reducing the number of steps required to fabricate the flow meter housing, not on casting in a single mold.” “While certain figures of the written description, namely Figures 5A and 5B, depict a single mold, the Board correctly found that those embodiments are narrower than the claims — which do not require use of a single mold — and correctly declined to import narrower limitations from the specification to the claims.” The Court determined that substantial evidence also supported the Board’s finding that the extrinsic evidence did not exclusively show that “cast in one piece” meant “cast in one mold.”

The Court held that because Kamstrup failed to show that the claimed process imparted “structural and functional differences” distinguished from the prior art, it was not entitled patentable weight.

The Court also reviewed whether the Board erred in its determination that the claims were anticipated or obvious. The Court addressed Kamstrup’s threshold argument that the Board erred in determining that Elson and Barker were analogous art because they related to “medical devices for thermodilution.” In support, Kamstrup cited disclosure in the ’957 patent explaining that it related to ultrasonic flow meter housing. However, the Board determined that Elson and Barker were analogous art because they were directed to sensing or measuring fluid flow and fluid flow characteristics such as temperature, and the ’957 patent was directed to flow meters that include different types of sensors. Thus, the Court found that substantial evidence supported the Board’s determination that Elson and Barker were analogous art because they were at least in the same field of endeavor as the ’957 patent.

The Court pointed out that “Kamstrup’s remaining challenges to the Board’s patentability determinations rise and fall with Kamstrup’s proposed claim constructions. Specifically, Kamstrup asserts that the Board’s erroneous claim constructions caused the Board to find incorrectly that the references disclosed the disputed claim elements.” The Court concluded that Kamstrup’s patentability challenges necessarily failed as they rely on the court accepting its proposed claim constructions. “[A]fter properly construing the claims, the Board found claims 1, 2, 5, 7, 9, and 11–13 anticipated by Ueki because it disclosed every limitation. The Board properly rejected Kamstrup’s arguments that Ueki did not disclose certain limitations as Kamstrup’s arguments were premised on its incorrect claim constructions. Thus, we hold that the Board’s decision that Ueki anticipates those claims is supported by substantial evidence. The Board also found claims 3, 4, 6, 8, 10, 14, and 15 obvious over Ueki and various secondary references. The Board found that a person of ordinary skill in the art would have been motivated to modify the references, crediting Axioma’s expert testimony. Again, the Board correctly rejected Kamstrup’s arguments that are conditioned on incorrect claim constructions.” Thus, the Court affirmed the Board’s written decision.

In this case, the Court reminded that in determining validity of a product-by-process claim, the focus is on the product and not the process of making it. “That is because of the . . . long-standing rule that an old product is not patentable even if it is made by a new process.” Greenliant Sys., Inc. v. Xicor LLC, 692 F.3d 1261, 1268 (Fed. Cir. 2012). If the process by which a product is made imparts “structural and functional differences” distinguishing the claimed product from the prior art, then those differences “are relevant as evidence of no anticipation” although they “are not explicitly part of the claim.” “The specification, the prosecution history, and any extrinsic evidence may enlighten whether structural and functional differences exist.” Amgen, 580 F.3d at 1365–67; Purdue Pharma L.P. v. Epic Pharma, LLC, 811 F.3d 1345, 1353–54 (Fed. Cir. 2016).