Downline wire
AssigneeDetnet South Africa (Pty) Ltd
InventorPhillip Olwage
Life of this patent
Estimating the term…
Abstract
A downline wire (10) serves to connect a location on the ground surface to at least one detonator (52) in a blast hole. The downline wire includes at least two flexible electrical conductors (12, 14) encased by respective flexible layers of an insulating material (20, 22) and a flexible sheath (24) in which the insulated conductors are embedded. Each conductor (12, 14) is made of a copper-clad steel core and the insulating material is either a filled flexible polyvinylchloride (PVC) composition or a polyester elastomer. The sheath (24) is made from a medium or high density polyethylene compound which includes carbon black.
Claims27
A downline wire for connecting a location on surface to at least one detonator in a blast hole, the downline wire including at least two flexible electrical conductors, a respective flexible layer of an insulating material which encases each conductor, and a flexible sheath in which the insulated conductors are embedded, wherein each conductor comprises a steel core which is clad with copper, the insulating material is selected from a filled flexible polyvinylchloride (PVC) composition and a polyester elastomer, and the sheath is made from a medium or high density polyethylene compound which includes carbon black.
A detonation system comprising:
- a detonator to provide a charge to ignite an explosive;
- and
- a downline wire to connect the detonator to a surface location, the downline wire comprising:
- two conductors;
- a flexible thermoplastic insulator encasing the two conductors;
- and
- a polyethylene sheath encasing the flexible thermoplastic insulator and the two conductors wherein the polyethylene sheath comprises a medium density polyethylene compound filled with carbon black (2.5%).
A method for loading a blast hole comprising:
- connecting a booster and a detonator to a downline wire, the downline wire comprising:
- two conductors with a tensile strength from 373 N/mm2 to 569 N/mm2, and an elongation at breakage from 18% to 30%,
- a flexible thermoplastic insulator encasing the two conductors, and
- a sheath encasing the flexible layer and the two conductors, the sheath comprising a polyethylene compound wherein the polyethylene sheath comprises a polyethylene compound filled with carbon black;
- placing the booster and the detonator in a blast hole;
- and
- filling the blast hole with an explosive material comprising an emulsion, a mixture, or both where the detonator experiences a dynamic force that causes the downline wire to elongate while the blast hole is being filled, and when a static force is exerted by the explosive material on the downline wire.
A method of manufacturing a downline wire for an explosive detonation system, the method comprising:
- providing two copper-clad steel cores;
- encasing each of the two copper-clad steel cores in a flexible thermoplastic insulator to form separate insulated conductors;
- and
- encasing both of the separate insulated conductors in a polyethylene sheath wherein the polyethylene sheath comprises a polyethylene compound filled with carbon black.
Dependencies are inferred from the claim text.