GB1249851A - Improvements in or relating to blast deflectors - Google Patents

Abstract

1,249,851. Blast shields. C. S. CROSS (U.S.A. Army, Secretary of). 4 March, 1965, No. 9359/65. Heading F3A. In order to prevent the sympathetic explosion of a charge of explosive in response to the explosion of another charge of explosive in close proximity, a blast deflector shaped to divide or split a shock-wave resulting from the explosion of either of the charges is interposed between the charges. By this means, a number of charges placed in alignment may be ignited successively and independently without a chain reaction occurring due to sympathetic explosions. Apparatus for testing the effectiveness of the invention includes a blast deflector 10 mounted on a base 12, on which base 12 are also mounted two supports 16, 20, each of which carries a charge of high explosive consisting of a rectangular rod 14, 18, respectively. These rods 14, 18 are in line with their end surfaces 22, 24, respectively, facing the blast deflector 10. The deflector 10 consists of a rectangular block of blast resistant material upstanding from the base 12 with the corner edges 10b facing the respective charge surfaces 22, 24 and has the effect of dividing or splitting the shock wave emanating from either charge if it should explode, thus providing a degree of shelter which is adequate to prevent the other charge exploding by sympathetic explosion. The surfaces 22, 24 are preferably chamfered away from the splitting edges 10b which has the effect of reducing the destructive quality of the blast from an exploding charge. Thus, if charge 14 explodes, the resulting shock wave presents a front with a leading edge of comparatively mild intensity followed by an increasing intensity, in which case an object such as the deflector 10 in the path of the shock wave is subjected to a more gradual build-up of pressure than if the surface 22 was squared. If the surface 24 on the charge 18 is similarly chamfered, then the destructive tendency of the shock wave from the charge 14 on the charge 18 is further reduced since the chamfered surface tends to p'ough into the wave much as the prow of a ship ploughs into a water wave. The use of a blast deflector 10 has proven adequate to prevent sympathetic explosions between charges even where the ends of the charges are not chamfered, but by the use of chamfering either a greater degree of safety is obtained or the blast deflector 10 can be made smaller or with a lower degree of blast deflection.