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FCA Construes Summary of Invention to Establish Common General Knowledge

March 12, 2015

By Ken Bousfield

Newco Tank Corp. v. Canada (A.G.)1

This case was a decision by the Federal Court of Appeal (FCA) affirming a decision of the Federal Court (FC) upholding a Re-Examination Board decision to reject claims in a re-examination of Canadian Patent 2,421,384.

CA 2,421,384 concerned use of waste heat from oilfield pumping equipment to warm stored crude oil.  In rejecting the claims as obvious given prior art patents in view of the knowledge of a person of ordinary skill in the art, the Board relied upon a statement in the Summary of the Invention as being evidence of the common general knowledge of persons of skill. No other evidence was cited by the Board in support of that conclusion.

That statement, following the heading “Summary of the Invention” was: “What is required is a more efficient method and apparatus for heating a liquid storage tank at a well site.”  This sentence was immediately followed by “According to one aspect of the present invention …”

It is fundamental to the patent bargain that the claims are granted in return for an enabling disclosure of the invention2.  Since the obiter statement of Jackett C.J. in Leitheiser v. Pengo Hydra-Pull3, alleging that the specification was inadequate, and that the claims were therefore broader than the disclosure4 it has been drafting practice in Canada to copy the claims into the Summary of the Invention.

In the subsequent Consolboard5 case, Jackett C.J., took the same approach, and was overturned in a decision that has formed the cornerstone of Canadian law on sufficiency of disclosure ever since.  In the appeal to the Supreme Court of Canada, (SCC), Dickson J., wrote6:

S.36(1)7 seeks to answer the questions:  “What is your invention?  How does it work?”

"We must look to the whole of the disclosure and claims to ascertain the nature of the invention and methods of its performance, […]8 being neither benevolent nor harsh, but rather seeking a construction which is reasonable and fair both to the patentee and public.  There is no occasion for being too astute or technical in the matter of objections to either title or specification, for … “where the language of the specification, upon a reasonable view of it, can be so read as to afford the inventor protection for that which he has actually in good faith invented, the court, as a rule, will endeavour to give effect to that construction”.

In Newco Tank, the FCA reaffirms that material in the “Background of the Invention” may be understood to reflect the common general knowledge of the person of skill.  It is quite controversial, however, also to conclude, that it was reasonable for the Board to have found that a statement made under the explicit heading “Summary of the Invention” may be understood to establish the state of common general knowledge in the art.

The FCA approach in Newco Tank appears difficult to reconcile with Consolboard.  A statement the patentee clearly cannot have intended to have been interpreted as “Background” appears to have been taken as establishing the state of the art against the patentee’s own claims, as if it were an object of the invention in the Background of the Invention.

Whether subsequently overturned by the SCC, the FCA decision in Newco Tank:

  1. underlines the importance of avoiding statements in the specification that can be construed inadvertently as “objects of the invention” or “problem and solution”;
  2. highlights the need for utmost fastidiousness in the Summary of the Invention; and
  3. reminds the writer of the importance of not telling the reader of asserted advantages or objectives, but of showing the reader, in the detailed description, what the invention is and how it operates, thereby demonstrating such advantages as it may have to overcome an existing problem, or to serve an unmet need.


1 Newco Tank Corp. v. Canada (A.G.), 2015 FCA 47, Affirming 2014 FC 287.

2 Consolboard v. MacMillan Bloedel (Sask) Ltd., [1981] 1 SCR 504, at 517: “Section 36 of the Patent Act lies at the heart of the whole patent system.  The description of the invention therein provided for is the quid pro quo for which the inventor is given a monopoly for a limited terms of years on the invention.”

3 Leitheiser v. Pengo Hydra-Pull (1974), 17 C.P.R. 2d 110 (FCA).

4 Ibid, 17 CPR 114 – 115.

5 Consolboard v. MacMillan Bloedel (Saskatchewan) Limited, (1974) 12 C.P.R. 2nd 117 (FCA).

6 Consolboard v. MacMillan Bloedel (Sask) Ltd., [1981] 1 SCR 504, at 520.

7 Now s. 27(3).

8 Citation omitted: Duff C.J.C. in Western Electric Company, Incorporated and Northern Electric Company v. Baldwin International Radio of Canada, at 574 – [1934] S.C.R. 570]


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