Patent ID: 6598679
Filing Date: 2003-07-29
Classification: E21B

Abstract:
An apparatus for cutting a conduit located in a borehole extending into the earth form the surface, comprising:an elongated body having an opening extending between an ignition end and a nozzle end with said body being adapted to be lowered into the conduit to be cut with said nozzle end located below said ignition end, said opening of said body comprises an opening having a central axis, combustible material located in said opening of said body, spacer means having a support surface and a lower end for supporting said combustible material in said opening of said body, said spacer means having an opening formed through said support surface, a nozzle and a diverter located at said nozzle end adjacent said spacer means with said nozzle located between said spacer means and said diverter and with said nozzle spaced from said spacer means, said spacer means having a surrounding surface formed between said opening of said support surface and said lower end forming an unobstructed mixing cavity within said surrounding surface above said nozzle, said cavity is defined at least by spaced apart planar boundaries and a surrounding wall located below said support surface and above a shield, said diverter comprising a surface which curves outward from a smaller circumference located near said nozzle to a larger circumference spaced away from said nozzle, ignition means located at said ignition end for igniting said combustible material to form a flame for passage toward said nozzle by way of said mixing cavity, said nozzle comprising a plurality of spaced apart apertures formed therethrough for directing the flame from said mixing cavity to said surface of said diverter for directing the flame radially outward of said body for cutting the conduit in the borehole, said apertures of said nozzle extend through said nozzle generally around and parallel to said central axis, said body at said nozzle end comprises a surrounding wall which extends to a position between said smaller circumference and said larger circumferences of said surface of said diverter such that said surrounding wall and said surface of said diverter within said surrounding wall form a second cavity for pressurizing the hot gases that flow from said apertures of said nozzle before leaving said body, said smaller circumference of said surface of said diverter is located radially inward of said apertures an amount greater than the radial distance of said apertures from said surrounding wall.