There is a certain charm to the stiffly drawn illustrations found in United States patent documents. The clear, static, highly conventionalized style evokes comic books and instruction manuals. Yet, in contrast to the ponderous, formal, lawyerly text of the patent, the hand of the artist can give the images a certain style of their own.
Here is Figure 1 from U.S. Patent 3,902,851, “Method of detecting odors and apparatus therefore,” by Andrew Dravnieks. It was granted on September 2, 1975. The illustrator did not sign his work, but I think it qualifies as a type of olfactory art.