Technikatörténeti szemle 19. (1992)

KÖNYVISMERTETÉS - Papers of the First „MINERALKONTOR” International Conference on the History of Chemistry and Chemical Industry (Veszprém, 12-16 August, 1991)

level of the mercury (the flow rate of the gas) was sensitively influenced by pressure (i. e. temperature), by means of the sensing bulb containing appropriate liquid and vapor. The so called tiltometer, was constructed by Parsons (31) in England in 1914. This automatic device served for controlling the dosing of aluminium sulphate reagent solution at the purification treatment of the drinking water. According to the flow rate of the water, the pressure difference between the two points of the Venturi tube tilted the arms of the balance in such a way, that at higher flow rate more reagent was fed to the water stream. SOLUTION OF REAGENT 4. Tiltometer, Parsons (31) 1914 The very first feed-back system controlled by the composition of the material flow was built in the twenties, patented by Harrison (32) in 1931 in the USA, and served for the regulation of the industrial cement production process. This system was first mentioned and described by Prof. Stock (33) in his pioneer paper on the early automation in chemical industry. Limestone and shale were fed continuously by the hoppers. After drying and grinding the mixture went down in a tube for processing. Sampling was done by