In 1966 Interstop AG was founded in Zürich by Didier Werke AG (Germany) and Dr. Tanner (former CEO of Concast AG, Switzerland). Both parties each held 50% of the shares. The main task of the new company was to develop and market a slide gate nozzle system to precisely control the flow of molten metal from the ladle to the tundish. The concept was based on a patent granted to David D. Lewis in 1885 (Figure 1) that had been revived and refined to fit the current needs of the steel industry.


The first slide gate nozzle system on the market was the INTERSTOP BK technology. Besides the mechanical slide gate system engineering by Interstop AG, Didier Werke AG developed and manufactured the corresponding slide gate ceramics.

Due to tremendous progress regarding safety, economy, and handling of the system, the 2000th INTERSTOP slide gate valve, mounted on a steel casting ladle, had already been commissioned at OvakoOy (Koverhar, Finland) by 1978.


Flow control partner for ladle, tundish, converter

Thanks to a worldwide network of sales representatives, set up by both Didier Werke and Stopinc, the INTERSTOP system became well established in the market. Over the years Stopinc has grown from a slide gate supplier to the steel industry’s flow control partner for ladle, tundish, and converter applications with the related hydraulic and electrical equipment. Next to product innovations, the highest priority was the early expansion abroad to establish the brand and technology in the global market. Therefore, already in 1977 “Interstop do Brasil” was founded, followed by a sales office in Singapore in 1980, Interstop Corp. USA in Mokena in 1986, and last but not least Interstop China in Shanghai in 2005.


Stopinc has always been dedicated to research and development, and it is especially noteworthy that all flow control technologies, including the four generations of ladle gates, were in-house developments. The CS and LC series, representing the fourth generation, is in operation at more than 170 steel plants worldwide. 2012 we designed the fifth generation of INTERSTOP ladle gates.