Board Reverses Examiner Rejections Because “Substantially” Is Descriptive Of A Known And Common Technique In The Art And The Examiner Failed To Establish A Factual Basis In Rendering An Obviousness Rejection

In Ex parte Evans et al. (Appeal 2011-004119; Application serial no. 11/823,993), the Board reversed the Examiner’s rejection under 35 USC §112, second paragraph, and the 35 USC §103 rejection over the prior art.

The Examiner was of the view that the term “substantially” in the claimed method for cooling an internal combustion engine was indefinite because there was no standard in the specification.  The relevant limitation at issue was “substantially filling the cooling system of the internal combustion engine with the heat transfer fluid such that the heat transfer fluid absorbs heat that is produced by the internal combustion engine and releases the absorbed heat to the atmosphere.” Appellants argued that the claim is definite because “one skilled in the art would readily understand what was meant by the use of the term.”

The Board agreed with the Appellants stating that “substantially filling” is used along with the functional recitation in the claim such that “any person skilled in the art, and indeed most laypersons, know, engine cooling systems may be considered ‘filled’ with slightly different levels in the cooling system. The terms ‘substantially filling’ are used in the claims as descriptive of this common technique and their use merely avoids a strict numerical level.”

The question answered in the obviousness rejection pertained to the heat transfer fluid and the specific weight ratio of propylene glycol relative to the combination of propylene and ethylene glycol.  There was no dispute that these glycols were known in the heat transfer fluid art but the Examiner proffered no evidence that the relative weight ratio was known.  Thus, the Board was left with an insufficient record and reversed the rejection because “evidence that merely shows the components are known, as in this case, is in our view insufficient to lead one of ordinary skill in the art to the particular combinations of components at particular proportions claimed.”