Developments of Siemens regenerative and tank furnaces at Saint-Gobain in the XIXth century
Résumé
In 2001, in the ICG conference in Edinburgh, M. Cable [1] examined glass making progresses during the industrialization of the 19th century. He observed that engineering and transport rapidly growing had a major influence on the scale of glass manufacture, increasing the ability to obtain fuel and raw materials and distributing products to the customers. Those factors largely contributed to the expansion of the glass industry but could not take place without improvements in technology. Among those new technologies, the Siemens regenerative furnace was a crucial development in glass making because it raised maximum achievable temperatures and greatly improved thermal efficiency. In 1954, F.W. Hodkin made a controversial communication to the Yorkshire Section of the Society of Glass Technology about the Siemens-Tank Story [2] which shows that there was some misinterpretation of information from W.E.S. Turner. Following this, the latter clarified his views to Hodkin who was stimulated to "enquire further into the points he has raised." The Siemens "principle", the use of gas producers coupled with a "regenerative furnace" dates back to the end of the 1850's (British patent No.1320 in 1861). It was applied first to metallurgical and very soon to glass furnaces [2]. The "tank furnace" was patented only in 1872 (British patent No.3478). In his letter reported by Hodkin, Turner said that "there is no doubt that the ideas of the Siemens brothers were worked out to a practical stage in England before being applied elsewhere [...] From about 1865 onwards Siemens's gas furnaces, which until then had only acquired a solid footing in England, began to appear on the continent". M. Cable [1] says that "in 1861 William having obtained a British patent was negotiating with Chance Brothers, who at first wanted an exclusive licence, which William would not grant, and dithered, even after accepting that decision." Looking at a well documented internal report written by H. de Coqueréaumont around the end of the first World War about the development of the plate glass technology in the Compagnie de Saint Gobain, it appears that, while William Siemens was discussing with Chance Brothers, or very shortly afterwards, in 1862, he was also in contact with the Glacerie de Montluçon, not yet part of the Compagnie de Saint-Gobain , with the same aim, selling his invention,recently patented (May 1861 No 49068). During the same year in November 1862, contacts between W.Siemens and Saint-Gobain resulted in an agreement and in May 1863, the first Siemens regenerative furnace was alighted in the Saint Gobain glass factory. Besides dealing with the Siemens furnaces (regenerator and later, continuous tank furnace) developments in the Compagnie de Saint-Gobain, by analysis of the technical data contained in this unpublished report, the present paper relates a few aspects of the story of the relationship of Saint-Gobain and W. Siemens extracted from the correspondence between the two parties during those critical years, which is kept in the Archives of Saint-Gobain.