Takeaway: In arguing against a prior art rejection, the Applicant distinguished the claimed heater from the reference heater by noting that the reference heater was not "completely embedded" in the container wall, because portions of the pipes carrying the heated water extended outside the wall. The Board found this interpretation was improper because it would exclude the Applicant's preferred embodiment and a dependent claim. According to the Board, the correct interpretation required only the heating means, not the entire heating system, to be within the container walls. (Ex parte Knetsch.)
Ex parte Knetsch
Appeal 2009012276; Appl. No. 10/835,487; Tech. Center 3700
Decided May 24, 2011
The application related to a container for a liquid used by a vehicle's catalytic converter.
1. A motor vehicle-mounted container for storing a urea-water solution, comprising:
a container having an interior space into which liquid can be fed ... wherein a free space is provided [which] corresponds to an increase in volume of a liquid that has frozen in said interior space, and
a heating means integrated into at least one of a base of the container and into a lateral wall of the container, such that said heating means is completely embedded in and surrounded by at least one of a material of the base and a material of the lateral wall of the container.
The Examiner combined three references: a first reference for the liquid container with heater; a second reference for the free space; and a third reference (Avramidis) for the embedded heater.
The Applicant argued that the third reference did not teach a heater that was "completely embedded and surrounded by" either the base or the side wall, but instead a heater that extended out through the container wall. (See element 20 in Figure below.)
On appeal, the Board first considered the proper interpretation of "embedded completely within." The Board found that the Applicant's proposed construction was "inconsistent with the Specification and the context of the claims." The Board noted that the specification described two alternatives for the structure of the heating means: "heating tubes that are connected to the coolant circuit of the  combustion engine"; or "an electrical heating means." As such, the heating system as a whole must extend out of the wall in order to connect with the coolant circuit or the electrical system. Applicant's Fig. 1, below, shows a cross section of the wall with heating tubes 20:
[T]o interpret “completely embedded” as excluding a structure wherein some portion of the structure responsible for heating the container exits the container wall would be interpreting the term to exclude the structure described in Appellants’ preferred embodiment and dependent claim 6, wherein the heating means is connected to the engine cooling circuit and, therefore, must extend out of the container wall at some location.
In interpreting the teachings of the reference, the Board also noted that the portion of the reference's heater that does not extend out of the container is the component that actually heats the liquid. Therefore, it was also proper to read "heating means" on that portion alone, which "render[ed] it irrelevant whether it connects to elements extending out of the container wall."
My two cents: Before anyone points out how ridiculous it is to file a patent application for a liquid container that includes a heater, I note that the novelty appeared to be related to preventing damage to the container by including space for the liquid to expand when freezing. Okay, maybe that's obvious too. But it was the claim construction issue related to the placement of the heater that caught my eye.
It's unusual for the Board to consider the preferred embodiment when arriving at a claim construction. The more common approach is to say that "embodiments from the spec are not imported into the claims." And I don't think I've ever seen the Board consider a dependent claim when interpreting a term in an independent claim.
The Board referred to the description of the preferred embodiment, but I didn't see any other embodiments where heating elements did not extend outside the wall, or a lot of boilerplate broadening language. Sometimes the Board points to this sort of language when saying "we won't import limitations from the spec into the claims."
So, on the whole, I guess I agree that the Board's interpretation was consistent with the spec while the Applicant's interpretation was not.
The claim element at issue was written in means-plus-function form, but that didn't seem to be dispositive. Probably would have had the same outcome if the term "heater" was used instead.
Finally, it usually turns out bad for the Applicant when the Board compares the drawings in the reference with the Applicant's drawings and the claimed feature looks the same in both.