If claimed limitations are taught by a combination of the cited art, it is very hard to overcome the obviousness standard of “obvious to combine.” Instead of formulating an obvious to combine argument, it may be easier to amend the claims.

I do not agree with the courts analysis that if each claimed element is taught by the cited art, the court is REQUIRED to find that it would have been obvious to combine the references. There are a few circumstances I have seen a not obvious to combine argument succeed. However, those arguments have won because the cited reference explicitly states something such as “this device cannot be used to do x,y,z” or “this device is restricted to being used in 1,2,3.” If an experienced patent attorney drafted the patent application for the cited art reference, then it is unlikely that such a statement will be made within the cited art.


In this case, Chevalie appealed a decision of the Patent Board of appeals, where the examiner affirmed the Examiner’s rejection of US Patent Application 11/407,778 (Chevalier).

The ‘778 application is directed towards a device for stirring a liquid in a reactor and for injecting gas into the liquid to form a gas-liquid dispersion. A representative claim and image are reproduced below:

1. A device for stirring a liquid in a reactor and for injecting a gas into the said liquid in order to form a gas-liquid dispersion, comprising:

a) a drive device positioned above the reactor, provided with a vertical output shaft fitted at its lower end with at least one axial flow rotor immersed in the liquid;

b) means for introducing gas above the axial flow rotor; and

c) a deflector placed above the axial flow rotor preventing the gas-liquid dispersion from rising, wherein said device comprises a deflector placed below the axial flow rotor converting the axial flow of the said rotor into a radial flow.

The claims were rejected as obvious in view of Kwak US Patent No. 4,290,885, Schreiber US patent No 4,310,437,  Howk US Patent No. 6,142,458, and Bouquet US Patent No 6,270,061. Kwak discloses a device for injecting a gas into a liquid, and the board found that Kwak meets each limitation regarding independent claim 1 except for Kwak includes a deflector that is not attached to the drive shaft but instead to the floor of the basin. Howk is directed towards a device for dispersing gas into a liquid utilizing a deflector to convert the flow of a liquid gas mixture into a radial flow. Similar to the deflector as recited in the claims of the ‘778 application, the deflector in Howk is secured to the drive shaft below the rotor. As such, the Examiner and the Board agreed that a combination of the cited art met each and every limitation as recited in independent claim 1 of the ‘778 application.

Chevalier argued that there is no motivation to combine the cited art because the resulting combination would be inoperable. Specifically, Chevalier argued that a literal physical combination of the art would not convert the axial flow of the gas-liquid mixture into a radial flow because the combination device would direct the radial liquid flow into a wall of the tube preventing the mixture from achieving suitable aeration.

The Examiner explained (and the board agreed) that the length of the drive shaft could be easily modified by one of ordinary skill in the art to avoid the alleged problem of combining the art. The court of appeals reasoned that an obviousness standard is not based on “whether the references could be physically combined but whether the claimed inventions are rendered obvious by the teachings of the prior art as a whole.” Therefore, in a case where each claimed element is known in the art, the obviousness inquiry requires a finding that the combination of known elements is obvious.

By | 2013-01-09T15:24:11+00:00 January 9th, 2013|Patent Attorney Takeaways|Comments Off on IN RE CHEVALIER