Solutions for Resistance-after-Fire Problems in an Electric Match

摘要

Current leakage in an electric match after firing is a problem if it drains power that can be used elsewhere or if it induces unwanted fluctuations in other electrical circuits. Two novel techniques are described that significantly reduce the RAF sensitivity of a Ti/KClO sub 4 -loaded electric match used to ignite the pyrotechnic materials in a thermal battery. In the first technique, a thin (less than 10 mu m thick) film insulator, such as Parylene or SiO sub 2 , is vapor deposited within the match cavity prior to the loading of the pyrotechnic. The insulator tends to smooth the cavity surface as an aid to ejection of firing residues and to decrease the exposed metal surface area to prevent pin-to-pin short circuits. The second technique involves placing a length of heat-shrinkable tubing on the match extending from the output end so that the shrink tubing is activated by the heat of the match and the thermal battery when fired. The shrinkage of the tubing effectively decreases the cross-sectional area for mass and heat transfer from the battery back into the match. 5 figures, 2 tables. (ERA citation 05:030743)