GB1176907A - Device for Determining Transition Temperatures - Google Patents

Abstract

1,176,907. Determining melting point temperatures electrically. W. C. HERAEUS G. m.b. H. June 4, 1968 [June 7, 1967], No.26591/68. Heading G1N. In the determination of the transition temperature of a specimen 4 Fig. 2 contained in a capillary tube 3 and in which a thermocouple element 5 is immersed, heat is supplied to the specimen at a constant rate, i.e. the difference in temperature between the specimen and its surroundings is maintained constant. The capillary tube is contained in a block 1 heated by resistance 2 and whose temperature is sensed by thermocouple element 7 connected in series opposition with element 5 to the input of a regulator 10 in which the voltage difference is compared with one of a plurality of fixed voltages and the error signal used to energize the resistance 2 to maintain the temperature difference constant. The element 5 is also connected in series opposition with a further thermocouple element 8 in a constant temperature enclosure, i.e. in iced water in a Dewar flask or in a heated metal block, to a recorder or digital or analogue meter 11 to indicate the temperature. This voltage may also be differentiated in a CR circuit 12 and metered at 13, the transition point occurrence being indicated by a fall in the indication of the meter. Alternatively or additionally the differentiated voltage may be used to start a recorder 15 at the start of the transition point or to actuate an audible alarm 12.