Abstract: The heat exchange mantle of a reaction vessel is connected with a circulating pump and a chamber provided with an electrical heating coil to form a heat exchange circulation system. To this main circulation system, a cooling circulation system comprising a circulating pump and a heat exchanger is connected by way of a continuously operable valve. The temperature of the medium circulating in the main circulation system can be very effectively and rapidly influenced by dosed addition of cooled circulation medium from the cooling circulation system into the main circulation system as well as by heating with the electrical heating coil. In the cooling circulation system, in the reaction vessel and in its mantle, temperature sensors are arranged which are linked to a control computer. The computer controls the electrical heating coil and the valve in such a manner that the temperature in the reaction vessel or in its mantle, respectively, has a desired distribution prescribed by the operational mode.

Abstract: A specimen testing apparatus is disclosed, including a sensing device for engaging a specimen mounted on a support, an electrical measuring system associated with the sensing device for producing an electrical signal that is a function of a variation in a physical characteristic of the specimen as determined by the sensing device, and an electromagnetic compensation system for applying a compensating force to the sensing device. In one operating condition (as, for example, when the thermal expansion properties of the specimen are being tested), the compensation system is operable to apply to the sensing device a force compensating for the weight of the sensing device, thereby to cause the sensing device to rest upon the specimen in a weightless force-free manner. Alternately, the compensation system may be operable to apply to the sensing device a supplemental force in the compressive stressing condition, as might be desired when penetration tests are to be conducted on the specimen.

Abstract: A method of, and apparatus for, carrying out thermoanalytical investigations at low temperatures, wherein an article to be investigated is placed in a heating chamber in a furnace and there is ascertained the temperature of the article or a measurement parameter that characterizes the temperature of the article. The temperature in the furnace chamber is brought to a predetermined value by a heating control circuit and a cooling medium is taken from a tank under substantially constant pressure to control the temperature in the furnace chamber. The throughflow of cooling medium is quantitatively controlled to produce a predetermined temperature difference between the furnace chamber and the cooling medium.