| 摘要 |
A primer assembly is provided for use in vertical boreholes wherein the primer charge is initiated by means of electric blasting caps, the electric caps, in turn, being initiated electromagnetically. A covered, cup-shaped primer assembly contains a toroid transformer element and connected electric blasting cap in detonating relationship with a primer explosive charge. The assembly is arranged to receive therethrough a looped wire conductor which conductor passes freely through the toroid transformer. When an energy source is coupled to the looped conductor, a magnetic flux is induced in the toroid transformer which sets off the cap and primer charge. The assembly may be passed freely or slid along the looped conductor to any location in the borehole. The assembly permits the use of electric time-delay, deck-charge blasting without the usual hazards associated with normal electric cap blasting. |
