Development Of Microscale Calorimeter

Fire is one of various disasters which often happens and has caused huge losses to the life and property. Thus studying the burning behavior of materials is an important issue for fire and flame retardant materials research institutions. A method for evaluating the combustibility of milligram samples is described. The development of a microscale pyrolysis combustion calorimeter is mainly based on ASTM D7309-13 Standard Test Method for Determining Flammability Characteristics of Plastics and other Solid Materials Using Microscale Combustion Calorimetry. The instrument separately reproduces the solid state and gas phase processes of flaming combustion in a nonflaming test by controlled pyrolysis of the sample in an inert gas stream followed by high temperature oxidation of the volatile pyrolysis products. In terms of size, the calorimeter fills the gaps in the field of domestic microscale instruments.Firstly, the research background, principle and theoretical model of the measured parameters of microscale pyrolysis combustion calorimeters are described, which establishes the theoretical basis for the development of the equipment.Secondly, the overall design of a microscale pyrolysis combustion calorimeter is introduced, including furnaces, sample weighing and supplying system, temperature controlling system and gas flow controlling system.Thirdly, the hardware circuit design of the data acquisition system is completed, mainly including the design of specified data acquisition board and temperature acquisition.Then, the development of the host computer procedure based on Lab VIEW is realized, which achieves a good design of man-machine interface. Besides, the basic functions of each module in the software are introduced, including serial communication test, oxygen sensor calibration, experimental preparation etc.Finally, the overall equipment debugging is operated completely and the measured parameters are compared with other fire test instruments over testing performance. The test result shows that the instrument basically meets the performance requirements of ASTM D7309-13 and has a good correlation with limited oxygen index instruments.