Changing the Sequence of Ingredient Addition

The decision of In re Burhans came as the result of an appeal from a final rejection at the USPTO over a number of rejected claims. Claim 4, shown below, will be considered illustrative for our purpose. 

In consideration of the appealed claim(s), the Court cited several prior art references. In particular, one of the cited references described the treatment of freshly prepared flour with carbon dioxide as a method of preventing its becoming rancid. 

The Court affirmed the rejection of this claim over a prior art description of a similar process, quoting from the USPTO s rejection  

Jahjah [the prior art reference cited by the USPTO] combines the preformed foam into various cement and concrete mixtures wherein known aggregates may optionally be incorporated. The foam is introduced from a reservoir into a concrete mixer containing the cement mix, and, in our opinion, it would be obvious to a technician having ordinary skill in the art to add the foam gradually to the cement mix while it was being mixed, since, as pointed out by the Examiner, conventional cement mixers operate in this fashion. Further, Jahjah obtains uniform dispersion of the foam and produces a multicellular cementitious product not differentiated in this record from that obtained by appellant. 

In a subsequent rejection of the same claim upon reconsideration, the Court further provided that the Appellant apparently relies upon continuous operation to differentiate over the Jahjah batch process. It is, however, well within the expected skill of the technician to operate a process continuously. So from the case of In re Dilnot, we learn that changing from a batch addition of an ingredient to a continuous addition will probably not be sufficient to escape a prima facie obviousness rejection. Of course this does not mean such a process is not patentable, only that unexpected results relative to the prior art batch addition would need to be demonstrated. 

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