On April 28, 2026, the Supreme People's Court issued the final judgment (2024) Zuigao Fa Zhi Min Zhong No. 658 regarding the dispute over infringement of invention patent rights between Hengyang Valin Steel Tube Co., Ltd. ("Appellant") and a certain French oil and gas company ("Appellee"), revoking the first-instance judgment and dismissing all litigation claims of the original plaintiff.
The Kangrui lawyer team assisted Hengyang Valin Steel Tube Co., Ltd. in achieving a complete victory in the second instance of this patent infringement lawsuit in the field of oil and gas equipment, which lasted for five years, winning back the business reputation and customer trust for Hengyang Valin Steel Tube Co., Ltd.
A certain French oil and gas company used its invention patent No. 02824417.6 titled "Improved Threaded Pipe Connection" as the basis of rights, alleging that a certain product manufactured and sold by Hengyang Valin Steel Tube Co., Ltd. constituted infringement. The court of first instance determined that the infringement was established and ordered Hengyang Valin Steel Tube Co., Ltd. to cease manufacturing, using, and selling, and to compensate for economic losses. This judgment posed a major threat to the market operations of the core product line of Hengyang Valin Steel Tube Co., Ltd. At the same time, it seriously affected the business reputation accumulated by the company over many years, causing Hengyang Valin Steel Tube Co., Ltd. to face serious doubts from several important customers regarding its products.
After being entrusted during the second-instance stage, the Kangrui lawyer team quickly studied and analyzed the first-instance judgment, precisely identifying the fundamental errors in the first instance regarding the understanding and comparison of the core technical feature "attachment" in the claims of the involved patent, as well as the entirely erroneous marking and determination of the female end structure of the accused product. Subsequently, an appeal strategy centered on claim construction and the doctrine of prosecution history estoppel was formulated.
The second instance of this case lasted for two full years, undergoing one court session, one inquiry, and multiple changes in the members of the collegial panel. The Kangrui lawyer team maintained close communication and collaboration with the client, repeatedly discussed technical details, and meticulously designed the trial plan, finding the best entry point to clearly present technical facts to the judges within the limited trial time.
Faced with the opponent's strategy of attempting to include the accused product within the scope of protection by expanding the interpretation of key technical features of the claims, the Kangrui lawyer team provided powerful counterarguments from multiple dimensions:
Obtaining and submitting the prosecution history files of the involved patent, invoking the doctrine of prosecution history estoppel to demonstrate that the opponent had explicitly excluded the technical solution adopted by the accused product from the scope of patent protection during substantive examination;
Simultaneously combining the text of the claims, the description, and the drawings to demonstrate that the accused product does not possess the key technical features of the involved patent.
The Supreme People's Court ultimately fully adopted the agency opinions of the Kangrui lawyer team, determining that the accused infringing technical solution was neither identical nor equivalent to the claims of the involved patent, and ruled to dismiss all litigation claims of the opponent.
Throughout the handling of this case, the Kangrui lawyer team consistently upheld a rigorous and professional practice attitude, fully invested professional resources, and maintained efficient and close collaboration with the client, ultimately successfully achieving a reversal in the second instance and completely eliminating the risk of patent infringement for the client.
The victory in this case not only effectively protected the normal production and operation of the client's core products but also restored the business reputation for the client and allowed its independently developed core products to shed the stigma of infringement. At the same time, the victory in this case also provides a practical example of reference value for Chinese enterprises in this field to respond to patent infringement lawsuits filed by foreign patentees.