Inventive step is NOT found
The Cited Invention was interpreted broadly.
In the explanation of FIG. 1, even if the lower purity oxygen is withdrawn as liquid, whereby a large amount of higher purity oxygen is obtained, it only illustrates the most preferred embodiment, and it cannot be considered that the withdrawal of lower purity oxygen as gas from side column 11 is not described in Cited Document 1.
<Writer: Hideki Takaishi (Attorney-at-law licensed in Japan and California)>