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

Abstract

A telescoping thermal lance assembly including a housing with an oxygen inlet port. An extension tube disposed in the housing. The extension tube having a cylindrical interior cavity. The extension tube configured to slide at least partially out of the housing when pressurized oxygen is channeled into the inlet port. A cylindrical lance tube is located within the interior cavity of the extension tube and slides partially out of the extension tube when pressurized oxygen is channeled into the housing. A slice rod is located within the lance tube. A cap is attached to the top of the extension tube and spaced apart from the tip of the lance tube. A tubular blow-out preventer sleeve is located between the cap and the top of the lance tube and has an outer diameter less than the inner diameter of the extension tube.

Claims

1. 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.

2. The telescoping thermal lance assembly of claim 1 wherein the sleeve has a bottom that rests against an upper edge of the lance tube.

3. The telescoping thermal lance assembly of claim 1 wherein the sleeve has a wall thickness of about 1/64 inch.

4. The telescoping thermal lance assembly of claim 1 wherein the sleeve is made from a combustible material.

5. The telescoping thermal lance assembly of claim 4 wherein the combustible material is low carbon steel.

6. The telescoping thermal lance assembly of claim 1 further comprising steel wool located in the igniter section.

7. The telescoping thermal lance assembly of claim 6 wherein the cap includes a hole and wherein a fuse extends from outside the cap through the hole into the igniter section.

8. The telescoping thermal lance assembly of claim 1 further comprising at least one wire inserted into an upper end of the slice rod in close proximity to the cap, the wire being made from low carbon steel, the wire extending into oxygen passageways in the slice rod and protruding from the upper end of the slice rod.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) For the purpose of the illustrating the invention, the drawings show a form of the invention which is presently preferred. However, it should be understood that this invention is not limited to the precise arrangements and instrumentalities shown in the drawings.

(2) FIG. 1 is a side view of an inner lance assembly according to the present invention.

(3) FIG. 2 is a cross sectional view of a thermal lance assembly including the inner lance assembly of FIG. 1 and a blowout preventer according to the present invention.

(4) FIG. 3 is an enlarged view of the top of the thermal lance assembly of FIG. 2.

DISCLOSURE OF THE INVENTION

(5) The present invention relates to an improved thermal lance for unplugging a vessel discharge port, for example, in a refractory lined ladle. As shown in FIG. 1, an inner lance assembly 10 includes a tubular thermal lance tube 14 with a lance rod 12, commonly called a burning bar or slice rod, disposed within the lance tube 14. The inner lance assembly 10 is located within an axially displaceable extension tube 16 which is located within the interior of a housing 1 to form a telescoping thermal lance assembly. The extension tube 16 may have a flared base or a base flange 15 (FIG. 2) to keep it centered in the housing 1, and the housing may include a bushing 19 near the top end to prevent the extension tube 16 from completely exiting the housing 1. The bottom of the tube 16 has an aperture 17 to allow oxygen to flow into the tube.

(6) As noted above, the inner lance assembly 10 (lance tube 14 and lance rod 12) and tube 16 are disposed within the outer housing 1. A conduit 18 communicates pressurized oxygen to the interior of the housing 1. When the apparatus is placed in line with an obstructed discharge port and an oxygen supply is opened, the oxygen flows through the conduit 18 and into the housing 1 raising the axially displaceable extension tube 16 toward the obstruction in the discharge port. Oxygen flows around and into the interior or the raised tube 16 through aperture 15 to facilitate rapid burning upon ignition in the vicinity of the obstruction, as is well known in the field.

(7) As extension tube 16 telescopes out of housing 1, lance tube 14 telescopes out of the tube 16. In addition, lance rod 12 telescopes out of lance tube 14. The telescoping extension tube 16 is preferably made of stainless steel or other high carbon steel to provide a lower rate of consumption than the more combustible material of the thermal rod 12 and lance tube 14 which are located inside extension tube 16. As tube 16 slides upward, the base flange 15 contacts the bushing 19 at the uppermost end of the housing 1 thereby preventing the extension tube 16 from exiting the housing 1.

(8) As discussed above, the combustible lance assembly 10 includes tube 14 and lance rod 12, both made of low carbon steel formed into a cylindrical rod that has substantial mass and surface area, yet allows oxygen to flow axially between and through the lance tube 14 and rod 12. The axial oxygen flow and increased surface area provide rapid ignition and burning in the presence of high temperature molten metal and oxygen flow.

(9) Referring to FIG. 3, the lance tube 14 is shown within the extension tube 16. (The housing 1 is not shown in this figure for simplicity.) A tip 30 of the lance tube 14 is located below the top of the extension tube 16. The tip of the lance tube 14 may be formed with one or more protrusions extending upward (in the illustrated embodiment) from the end of the lance tube 14. The protrusions facilitate ignition of the thermal lance assembly. The details on the lance tube and the protrusions are described in U.S. Pat. No. 11,187,461 titled “Tip Protrusions On Lance Ignition Tube”, filed concurrently herewith, the disclosure of which is incorporated herein by reference in its entirety. A cap or bullet tip 60 is preferably attached to the top of the extension tube 16. An igniter section 50 is defined between the tip 30 of the lance tube 14 and the bottom of bullet tip 60. Steel wool (not shown in FIG. 3) or other porous combustible material is located in the igniter section 50. It is also contemplated that volatile material, including liquids, solids, or semi-solids could be added to the igniter section 50 to facilitate ignition. The outer diameter of the lance tube 14 is less than the inner diameter of the extension tube 16, thus leaving a gap between the lance tube 14 and the extension tube 16 defining a passageway 40 through which oxygen can flow. The lance tube 14 includes an inner bore 22 containing the slice or lance rod 12 which is also designed for oxygen to flow through to the igniter section 50. Slice rods, and the process of making them, are described in U.S. Pat. No. 4,787,142.

(10) The bullet tip 60 includes a hole 62. A low temperature blasting fuse 64 preferably extends through the hole 62 into the igniter section 50. The fuse 64 protrudes out from the cap as shown to facilitate lighting.

(11) In order to temporarily reduce the oxygen flow during ignition, a plurality of fine wires 66 are inserted into the slice rod or burning bar 12. The wires are preferably made of low carbon steel and configured to ignite when exposed to the burning fuse 64 and steel wool. The wires 66 are inserted in a short distance, preferably approximately ½ inch into the oxygen passageways in the slice rod or burning bar and protrude out of the slice rod approximately ¼ inch so as to be in close proximity to the fuse 64. As should be apparent, the wires 66 work in conjunction with the steel wool or other combustible material in the igniter section 50 to provide additional ignition sites and reduce oxygen flow to further improve ignition reliability.

(12) It has been determined that sometimes the heat and pressure during combustion can cause the side wall of the extension tube 16 above the lance tube 14 to blowout. Accordingly, the present invention incorporates a tubular blow-out preventer sleeve 70 in the igniter section 50 above the tip 30 of the lance tube 14 inside the extension tube 16. The sleeve 70 is preferably made from stainless steel, carbon steel or combustible material, with an outer diameter slightly less than the inner diameter of the extension tube 16 so that it can slip snugly in. The sleeve 70 preferably has a wall thickness of about 1/64 inch, thereby providing the ignition zone 50 with increased protection against blowout.

(13) The incorporation of the preventer sleeve 70 not only adds lateral strength to the extension tube 16, but also prevents inadvertent compression of the steel wool during shipping. The inventor has determined that shipping can sometimes cause the lance tube 14 to move toward the cap 60 compressing the steel wool. This can lead to a gap forming between the fuse 64 and the steel wool which can lead to reduced ability of the steel wool igniting. Similarly, it is sometimes necessary to test the ability of the thermal lance assembly to extend. In those cases the user applies pressurized oxygen to test the sliding of the tubes without lighting the fuse. This can cause the lance tube 14 to compress the steel wool.

(14) The present invention overcomes those issues by providing a stiffened ring of combustible material in the ignition section 50 to inhibit or prevent relative movement between the lance tube 14 and the cap 60.

(15) As used herein, the term “engage” is intended to both direct physical engagement through one or more components as well as operative engagement.

(16) The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. The term “connected” is to be construed as partly or wholly contained within, attached to, or joined together, even if there is something intervening.

(17) All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate embodiments of the invention and does not impose a limitation on the scope of the invention unless otherwise claimed. The various embodiments and elements can be interchanged or combined in any suitable manner as necessary.

(18) The use of directions, such as forward, rearward, top and bottom, upper and lower are with reference to the embodiments shown in the drawings and, thus, should not be taken as restrictive. Reversing or flipping the embodiments in the drawings would, of course, result in consistent reversal or flipping of the terminology.

(19) No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

(20) It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention. There is no intention to limit the invention to the specific form or forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention, as defined in the appended claims. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalent.