In 1979, Mr. Van Rijn sold his company to Siersema. At the time, Siersema had engineering factories in Wassenaar and Den Bosch, and later also in Waalwijk, Boxmeer, Valkenburg, Heerenveen, and Belgium. These specialized in process technology. By taking over the production at these locations Van Rijn was able to further grow the business and to provide total solutions in various sectors, such as food processing, flowers, chemicals, vegetables, fruit and fisheries, both in the Netherlands and abroad. The fishing industry remained the primary focus and the machines found their way to many companies and more than a thousand cutters and trawlers. These ships were equipped with all kinds of fish processing equipment, from simple conveyor belts to complete processing decks with sorting installations, vacuum pumps and packing machines. However, the general food processing, flower, and fruit and vegetable industries became increasingly important.