SEB v. PRB and Tall & Stout

By Zhang Shuhua, Wanhuida Peksung

SEB SA owns an invention patent titled “Dry Fryer” (Application date 8 June 2005, priority date 8 June 2004 and granted on 13 April 2011). Tall & Stout Home Appliances (Shenzhen), Yuan Yuxing and Yi Chunhua respectively and successively applied to the Patent Reexamination Board (PRB) of the State Intellectual Property Office of China to declare the patent invalid. As defined in the patent, the dry fryer comprises main body for accommodating the food to be fried, container means, stirrer means, and main heater means (that is mounted on the main body and designed to generate heat flow directed to strike substantially directly at least a portion of said food and provides at least majority of the heat for cooking).

张树华 ZHANG SHUHUA 万慧达北翔合伙人 Partner Wanhuida Peksung
Wanhuida Peksung

An automatic cooking apparatus disclosed by evidence 1 in the invalidation request differs from the patent only in the heating approach, in that the former adopts the traditional approach, namely that heat source and food are separated by the container bottom. Evidence 3 discloses impingement oven airflow devices and methods.

The PRB held that both approaches, namely heating by striking directly the surface of food through heat flow and heating indirectly from the bottom, were regular heating approaches in the cooking equipment field and well known by those skilled in the art, who then had motivations to replace the heating means of evidence 1 with that of evidence 3. Accordingly, the PRB held that the patent lacked inventiveness.

SEB filed an administrative litigation before the Beijing First Intermediate People’s Court, which revoked the PRB’s decision. The third party Yuan Yuxing appealed to the Beijing Higher People’s Court, and the court affirmed the judgment in February 2017.


As defined by article 22.3 of the Patent Law (2001), inventiveness means that compared with prior art before its application date, the invention should have prominent substantive features and notable progress. The Patent Examination Guidelines further provides that in the course of determining inventiveness of an invention, what’s to be determined is whether or not the prior art as a whole gives a motivation to apply the distinguishing features to the closest prior art. The distinguishing feature between the patent and evidence 1 is “heat flow directed to strike substantially directly at least a portion of said food”, which is disclosed by evidence 3. Both the PRB and the appellant claim that a person skilled in the art has motivation to replace the heating means of evidence 1 with that of evidence 3, while SEB claims the contrary. The issue of this case therefore is whether or not a person skilled in the art has motivation to combine evidence 1 and 3 to obtain the patent.

Evidence 3 discloses impingement oven airflow devices and methods, wherein individual heat transfer elements are affixed to each air pipe or conduit in close association with jet nozzles, and heat transfer elements may comprise device such as electrical heating coils. Jets from jet nozzles go through heat transfer elements and form heat flow which heats food by striking perpendicularly to the surface of the food, and this provides a majority of heat for cooking.

Courts of both the first instance and the second instance admit that evidence 3 discloses the technical features regarding heating approach of the patent’s main heating means, but at the same time point out that evidence 3 applies those technical features to baking devices rather than frying devices to which the patent belongs. Generally speaking, different cooking styles are based on different cooking principles to achieve their respective unique cooking effects (such as taste). Their heating approaches are relatively definite and heating approaches of other cooking styles cannot replace their own general options.

The patent and evidence 3 have applied different cooking styles to achieve different cooking effects based on different cooking principles. The technical features regarding heating approach in evidence 3 could not be conceived in combination with evidence 1 to obtain the technical solution of the patent. Besides, the technical solution of the patent can use less oil to achieve the frying cooking style and realize the unexpected technical effects of frying. Therefore, the person skilled in the art does not have motivation to combine evidence 1 and 3 to obtain the patent. The patent hence has inventiveness.


The judging rule of this case can be understood as: if integrally compared with prior art of another technical field, the patent applies different technical principle to achieve different technical effects, there is usually no combining motivation. It needs to be pointed out that the appellant Yuan Yuxing claims in his appealing arguments that the heating approaches of both evidence 3 and the patent are to solve the same technical problem, which is to achieve heat exchange, so combining motivation exists. The court of the second instance, however, does not accept and consider the identicalness of technical problems as a factor to determine the existence of combining motivation.

Courts of this case, through judgment of whether there exists combining motivation between the frying field and the baking field, clarify the integral comparison principle in the judgment of technical motivation and point out the factors to be considered in identifying the motivation, which has guiding significance for judging combining motivation between different technical fields.

Zhang Shuhua is a partner at Wanhuida Peksung



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