Protecting the essence
The proceedings took so long partly because the Court of Appeal gave the parties the opportunity to present their views on another judgment, passed by the Supreme Court in the case of Lely v. Delaval.
In that judgment, the Supreme Court presented its views on the interpretation of Article 69 of the European Patent Convention (EPC) and on the manner in which the Protocol on the Interpretation of Article 69 EPC is applied in the Netherlands. It requires the determination of the essence of an invention in order to establish the extent of protection conferred on an invention.
The protocol says that the extent of protection is not defined by the literal meaning of the wording. Nor are the claims a guideline as to what is considered from the description and drawings. The extent is a position between these extremes.
The Supreme Court ruled that the interpretation of Article 69 in relation to the literal wording used in the claims must be based on the idea of the invention underlying the wording of the claims; however, that perspective does not indicate how to find “a position between these extremes”. It also ruled that any lack of clarity in the wording of the claims is to the detriment of the patentee.
Zilka and Rüegg have both developed a product that can be used to deslag heat-exchange devices. Zilka believes that Rüegg’s system includes the essence of its patent and therefore infringes its patent either literally or on the grounds of equivalence. This is therefore also a case of determining the essence of the invention and the extent of the protection.
“Any lack of clarity in the wording of the claims is to the detriment of the patentee."
Zilka argues that the essence of its invention is an explosive-based system for deslagging a heat-exchange device, whereby the explosive device can be moved to any desired position and the explosives can be detonated at any desired moment, since the explosive device is cooled continuously. The parties have a difference of opinion as to how a person skilled in the art will interpret an “explosive device”.
Zilka believes that its explosive device should be interpreted so broadly that it also includes Rüegg’s product: a balloon filled with an explosive gas, attached to a hollow lance.
The Court of Appeal studied the wording and drawings of the patent, and concluded that “explosive device” means “explosive” and that the lance is a separate part. The prior art for Zilka’s patent also does not allow Zilka’s interpretation, nor would a person skilled in the art make such an interpretation. So there is no literal infringement.
As for the “position between these extremes”, Zilka argues that, for infringement to occur, all characteristics related to the essence of the invention must be contained in the challenged device, and that infringement may also be deemed to occur if a characteristic is missing that is irrelevant from a technical perspective. Therefore, Zilka believes that the essence of its invention is found in Rüegg’s system.
The Court of Appeal found that Zilka disregarded many characteristics and eliminated them in its interpretation of the essence of its invention. For instance, Zilka eliminated the cooling envelope in its interpretation, even though it is described in detail in the claims and therefore appears to be essential.
Zilka does what Article 69(1) EPC attempts to prohibit, namely removing a limitation from a claim in order to broaden the extent of protection. There is no infringement on the basis of equivalence either since although the same result is achieved by both systems, the manners in which that is done are essentially different. A person skilled in the art would not regard that difference as equivalent.
Michiel Rijsdijk is a partner at Arnold + Siedsma. He can be contacted at: mrijsdijk@arnold-siedsma.com
