TOPICS

“Melting Furnace”

Overview:

This case upheld a trial decision to dismiss a request for a patent invalidation trial for the inventions according to claims 3 to 5 (hereinafter, “Present Invention 3”, etc.).

▶Summary of Judgement and Link to Full Text (Japanese)

Main Issue:

Whether there is motivation to adopt a flat flame burner (Present Invention 3) instead of the holding burner (regenerative burner) of the invention of Plaintiff’s Exhibit 3, whether there is motivation to further provide a heat exchanger in the invention of Plaintiff’s Exhibit 3 (Present Invention 4), and whether there is motivation to make the door of the invention of Plaintiff’s Exhibit 3 unnecessary (Present Invention 5).

Summary:

The tower-type non-ferrous metal melting and holding furnace of the invention of Plaintiff’s Exhibit 3 can be recognized as having deliberately adopted a regenerative burner as the holding burner from the standpoint of energy efficiency, etc., despite the fact that at the time it went on sale flat flame burners were well known for use in aluminum melting and the like. As such, it is not recognized that there would have been motivation for a person skilled in the art exposed to the invention of Plaintiff’s Exhibit 3 to deliberately adopt a flat flame burner in place of such a holding burner.

Therefore, Present Invention 3 is not something that the skilled person could have easily conceived of on the basis of the invention of Plaintiff’s Exhibit 3… As stated above…, in the invention of Plaintiff’s Exhibit 3, it cannot be recognized that there is motivation to adopt a flat flame burner as the holding burner, and it must be said that the plaintiff’s aforementioned argument lacks that premise. A regenerative burner… has a function of drawing exhaust gas, performing heat exchange with a heat storage body, and preheating the air, and since it is equipped with a heat exchanger, … it cannot be said that there is motivation to further provide a heat exchanger in addition to this. … The invention of Plaintiff’s Exhibit 3 uses a regenerative burner as the holding burner…, and because one flux treatment per day is necessary, a door for cleaning is also needed, and it cannot be recognized that there is motivation to make this unnecessary.

Comments:

The invention of Plaintiff’s Exhibit 3 is an invention described in a catalog prepared by Daiki Aluminium Industry Co., Ltd., as of May 1997, concerning the tower-type non-ferrous metal melting and holding furnace “TERRA PAC MELT,” and relates to a finished product that had already been sold on the market. That is, the starting invention for determining inventive step for this case was based on a finished product that was actually in circulation. Taking such a finished product as the starting invention, it is conceivable that changing the burner, which is an important component of the melting furnace, would have been difficult without fairly strong motivation, even if flat flame burners were well known.

Yuuji WADA