Experimental Study On Influencing The Precision Of The Delay Composition

In the production of industrial detonator in domestic, the precision of the delay composition is limited by the development of combustion theory and delay technology which makes a low precision. To satify the needs of the precise millisecond blasting work and improve delay composition precision, the delay time, combustion temperature and combustion pressure test systems were developed with red lead-silicon delay composition as basic formula in this dissertation. Furthermore, a high-speed camera test system was set up to observe the combustion propagation status of the delay composition. A series of factors influencing the precision of the delay composition were studied, and conclusions as the followings:(1) Firing process of the fusehead, based on firing process of the bridgewire, is added with the influences of the deflagration of powders. The process contains molten comburent, high temperature heat flow and weak shock wave, with combined action of those regions the delay element is ignited. Electric current circulating through the bridgewire, powders mass of the fusehead and the size of the gas cell reach to the optimum values the delay precision improving. When the delay element ignited by the Nonel, the length of the Nonel and the detonation elimination chamber achieving the best match brings a more reliable ignition and a higher precision.(2) According to the relationship between the structure of the columnar delay composition and the precision of the delay composition, the experimental studies showing as the follows:Increasing the loading density forcing the compactibility of the components which makes for the combustion propagation of the delay composition steadily and improves the delay precision. The length of the columnar delay composition and restraint coefficient 8 have an effect on the delay precision, and intrinsic quality of which lies in the dynamic equilibrium of heat release and heat conduction. At the moment the burning rate is more stable and the delay precision is higher. A suitable clipping pressure, different numbers of the cores and a spacer can improve the precision of delay composition.(3) According to the relationship between the powders and the precision of the delay composition, the results show as the following:As the mass ratio of Si and Pb3O4 equal to 3/7, solid phase reaction is the main reaction for the delay composition, of which combustion propagation is more stability and delay precision is higher. The grain size of the silicon is smaller, the higher precision of the delay composition, and while a higher costing. The binders can increase the storage stability of the delay composition, however, the effect of the binders on the delay precision needs to control intentinonally.(4) According to the relationship between storage status and delay precision of the delay composition, the experimental studies show as the followings:Thickness of the silicon dioxide film on surface of the silicon tends to stable in aged delay composition, after loading or drawing to a delay element, thickness of the oxide film increases slowly and even no longer increases. At the moment the chemical state between the oxidant and silicon surface also tends to steady, that is the physicochemical property and delay precision.