DEVICE FOR CUTTING BY BLASTING Russian patent published in 2000 - IPC

FIELD: oil-and-gas producing industry; applicable in cutting by blasting of members of structures of offshore oil and gas production platforms during their dismantling. SUBSTANCE: device has cylindrical body whose cavity accommodates explosive charge and means of initiation, and plugs are installed on both sides of explosive charge in immediate contact with it. Plugs are distinguished by the fact that they are made of successively arranged along body axis three parts whose extreme ones are made of ductile metal, and middle one, of plastic material with acoustic stiffness which is lower than that of material of plug extreme parts. Total height of a plug equals or exceeds 0.9 of explosive charge diameter. Acoustic stiffness of ductal metal of plug extreme parts shall amount to R≥30•10⁶kg•s^-1•m^-2, and acoustic stiffness of material of plug middle part equals (4-10) 10⁶kg•s^-1•m^-2 and its weight does not exceed 10% of plug total weight. Weight of plug part adjacent to explosive charge equals not more than 10-20% of plug total weight. EFFECT: increased efficiency in cutting of thick-walled solid steel pipes and breakage of multiple conductors whose interpipe space filled with cement mortar or some other filling material of low stiffness. 4 cl, 1 dwg