US Patent 7992495 Detonation of explosives

A chemical detonator includes a housing, having an open end and a closed end; and a detonation element located in the housing, into which a shock tube for initiating the detonation element intrudes, wherein the housing and the shock tube are of plastics construction and the housing is substantially cylindrical cup shape, and wherein the shock tube intrudes into, and is welded to, the open end to hold the shock tube at a desired spacing from the detonation element. The detonator includes a detonation element that includes a series of charges.