Technikatörténeti szemle 10. (1978)

A MÉRÉS ÉS A MÉRTÉKEK AZ EMBER MŰVELŐDÉSÉBEN című konferencián Budapesten, 1976. április 27–30-án elhangzott előadások II. - Tálos Gy.: A reológiai mérési módszerek fejlődésének története Newtontól napjainkig

GY. TALOS* HISTORY OF THE DEVELOPMENT OF RHEOMETRY FROM NEWTON TO OUR DAYS More than thousand years have passed, that Herakleitos, a Greek philosopher said: ,,panta rhei", i.e. everything is flowing, but since that time the importance of studying the laws governing the ability of deformations of the materials kept on going. From the middle of the past century, the revolutional development of technology and natural sciences emerging from new industrial procedures and problems in connection with processing and employing new changed and artificially produced materials just directly claimed the development of rheology and rheometry. Newton can be considered the first rheologist, who created the basic law of the viscous flow and the mathematical basis of the rotational viscometry in his work, the „Philosophiae Naturalis Principia Matemathica" in 1687. The period passed since that time can be divided into three parts: the first part was till the turn of the century—we may call it the era of the classical viscometry—the flow properties of the materials were approached with hydrodinamical methods. In the second part, from the turn of the century to the middle of the 20-s of this century, those basic experiments were carried out, which led to the flow model of the materials and the exact mathematical basis of the rheometry. Since that time we can speak of the third part, in which the development is very fast, after World War II chiefly, from the middle of the 50-s. In the highly industrialized countries (Soviet Union, U.S.A., Japan and Great Britain) research groups were formed with several hundreds of people to try to solve problems due to industrial, technological or scientific claims. To point out this reason and the extreme importance of this branch of science, I'll mention some industries and their technological processes—with the reference that rheology is important from every respect of our life in the deformation processes of the gases, through that of the fluids to that of the solids—: in the mineral oil industry; the qualification of the products according to their viscosities, in the polymer industry; the qualification of the end products, the modelling of the rheological processes in the processing devices and the measurement of progress of the polymerization, in the paint industry; the rheometrical qualification concerning the production and the characterization of processes when the paints are being carried up, * National Office of Measures, Budapest.