1994 Volume 10 Issue 6 Pages 889-893
Heat-exchange calorimetry has been extended to the flow type. Two glass vessels for the sample and a reference are fixed separately in a precision water bath. In each vessel, a thermistor, a heater element, an inlet of the solution and an outlet for any overflow are installed. Heat released in the sample vessel is freely exchanged with the ambient water. The temperature in each vessel is observed by a thermistor associated with a Wheatstone bridge. The amplified output is introduced into an analog computation circuit in order to calculate the total heat effect. A constant related to the heat transfer of vessels was theoretically found to be proportional to the flow rate; it was subsequently confirmed experimentally by changing the flow rate from 30g/min to zero, corresponding to the batch type. Since the constancy of the peristalsis pumps is not satisfactory, the flow rate at every setting is observed by means of time and mass measurements. The necessary evaluations for precision and reproducibility are executed in water by electric heating; successful results were obtained for practical use.