Lance with blowout preventer, oxygen flow reducer and improved ignition system

A telescoping thermal lance assembly for use in unplugging a vessel discharge port, the telescoping thermal lance assembly comprising:

• a housing with an upper end that has an opening, and an oxygen inlet port located on the housing spaced apart from the upper end, the oxygen inlet port configured to connect to a supply of pressurized oxygen;
• a cylindrical extension tube disposed in the housing and extending partially out through the opening of the upper end of the housing, the extension tube having an open top and a closed bottom opposite the open top with a sidewall extending between the open top and the closed bottom, the extension tube having an inner diameter defining a cylindrical interior cavity, and an aperture extending through the sidewall or the closed bottom for permitting a flow of oxygen to enter into the interior cavity, the extension tube being slidingly disposed within the housing and configured to slide at least partially out of the opening in the upper end of the housing when a supply of pressurized oxygen is channeled into the inlet port;
• an elongated cylindrical hollow lance tube made from a combustible material, the lance tube having an axial length with first and second ends, the lance tube having a cylindrical sidewall defined by an outer wall having an outer diameter and an inner wall having an inner diameter, and the sidewall has a wall thickness between the outer and inner walls, the lance tube having a longitudinal axis, the lance tube being slidingly disposed within the interior cavity of the extension tube and configured to slide at least partially out of the open top of the extension tube when a supply of pressurized oxygen is channeled into the aperture;
• a slice rod located within the inner wall of the lance tube, the slice rod being formed from low carbon steel;
• a cap attached to the open top of the extension tube, the cap located spaced apart from the tip of the lance tube, the space below the cap and above the tip of the lance tube defining an igniter section;
• a tubular blow-out preventer sleeve located in the igniter section above the tip of the lance tube and inside the extension tube, the sleeve having an outer diameter less than the inner diameter of the extension tube, wherein the sleeve has a wall thickness that is wider than any gap between the outer diameter of the lance tube and the inner diameter of the extension tube.