Post-combustion lance including an internal support assembly

A post-combustion lance for directing a gas at least partially therethrough. The post-combustion lance includes a body extending between an upstream end and a downstream end of the lance, the body including upper and lower portions and a post-combustion distributor mounted therebetween. The lance also includes an internal support assembly for supporting the body, the internal support assembly including an internal tube positioned inside the body and at least partially engaged with the lower portion, and at least partially engaged with the upper portion of the body, so that the internal support assembly supports the body both upstream and downstream relative to the distributor. The lance also includes a lower o-ring gland positioned downstream relative to the internal support assembly and an upper o-ring gland positioned upstream relative to the lower o-ring gland.

FIELD OF THE INVENTION

This invention is related to a post-combustion lance with a body including an internal support assembly for supporting the body.

BACKGROUND OF THE INVENTION

Metallurgical processes such as basic oxygen steelmaking often employ large water-cooled oxygen lances (typically, about 8 inches to about 16 inches in diameter and approximately 65-85 feet long) to efficiently remove oxidizable elements from molten metal in a metallurgical converter. These lances, which typically weigh up to approximately 10 tons, are known as post-combustion lances. Typically, in addition to the primary oxygen ports at the tip of the lance, the prior art post-combustion lance includes a ring of small oxygen ports located on the outside of the lance a distance up the lance from the primary oxygen tip. The ring is known as a post-combustion (or “PC”) distributor.

Due to heat transfer requirements, and also to protect the PC distributor from the furnace atmosphere and the localized heat generated from the post-combustion reaction, the PC distributor (and often, the piping associated therewith) is made of high thermal conductivity metals such as high purity copper.

Although the post-combustion lance often is used to direct oxygen into a metallurgical converter, various other gases may be directed through the lance, depending on the reactions desired. Any and all reaction gases directed through the lance are generally referred to hereinafter as a “gas” for convenience, it being understood that the gas may be oxygen or any other reaction gas, or any mixture of any such gases. Typically, the gas is injected through the lance at very high rates. For example, oxygen may be injected into the lance at rates of between 300 cubic meters/min. and 600 cubic meters/min.

Cross-sections of a typical post-combustion lance10of the prior art are provided inFIGS. 1A and 1B.

The lance10extends between an upstream end12, at which the gas is introduced therein, and a downstream end14, at which a primary tip16is positioned. The introduction of the gas at the upstream end is represented by arrow “A” inFIG. 1A. A PC distributor18is positioned at a predetermined distance (designated “L” inFIG. 1A) from the end of the tip16. The typical lance includes a lance body20having an upper portion22and a lower portion24, being the outermost tube elements. The upper portion22typically has slightly larger inner and outer diameters than those of the lower portion24respectively. The body20includes the PC distributor18, which is mounted between the upper and lower portions22,24, as shown inFIG. 1B. Typically, the upper and lower portions22,24are substantially round in cross-section, i.e., they are generally cylindrical.

As shown inFIGS. 1A and 1B, the prior art post-combustion lance10typically (but not necessarily) also includes an upper inner tube26with an upstream first portion28, a larger second portion30, and a connecting portion32connecting the first and second portions28,30. Also, a lower inner tube34is positioned inside the body20, downstream from the upper inner tube26. Typically, the upper and lower inner tubes26,34are positioned coaxial with each other and with the body20. The upper and lower inner tubes26,34are shaped to direct part of the gas to the PC distributor18, and also to direct a part of the gas toward the lower inner tube34, from which such part exits the lance at the tip16. For example, the first part of the gas typically may be about ten percent of the gas flowing through the lance, with the second part being the balance. The part of the gas exiting the PC distributor is represented by arrows “B” inFIG. 1A, and the part of the gas exiting the tip16is represented by arrow “C” inFIG. 1A.

As is well known in the art, the upper and lower portions22,24typically include cavities25through which water (not shown) is circulated while the post-combustion lance10is in use, to cool the lance body20. Typically, the water is introduced at the upstream end12into an intake cavity which extends to the downstream end14and the primary tip16, and the water returns to the upstream end14via an output cavity. The cavity25is at least partially defined by an upper intermediate element29in the upper portion22(FIG. 1B). In the lower portion24, the cavity25is at least partially defined by a lower intermediate element31.

As is also well known in the art, both the upper inner tube26and the lower inner tube34are secured to the body. The upper and lower portions22,24are substantially cylindrical, and positioned substantially coaxial with each other. For instance, the axes defined by the upper and lower portions22,24are identified by reference numeral27inFIG. 1B. In addition, the upper inner tube26typically is positioned substantially coaxial with the upper and lower portions22,24. Also, in the prior art lances in which the lower inner tube34is included, the lower inner tube34(which typically is substantially cylindrical) typically is positioned substantially coaxial with the upper and lower portions22,24and with the upper inner tube26. It will be understood that various prior art lances are known.

The lance is subjected to bending stresses during its service life, particularly during loading and unloading operations and during lance deskulling operations, where steel and slag buildup on the lance exterior surfaces36is removed using aggressive mechanical means, including, e.g., machinery employing hydraulic and/or pneumatic hammers and steel tips. When in use, the lance typically is supported only at the upper portion (i.e., above the distributor). Accordingly, the prior art lance typically is subject to deflection (i.e., substantially or at least partially transverse deflection) due to the bending stresses to which it is subjected. For example, the prior art lance10inFIG. 1Bmay be urged to deflect transversely (i.e., relative to the axis27) by downward deflection of the lower portion relative to the upper portion, as indicated by arrow “D” inFIG. 1B.

Lances equipped with the PC distributor typically are prone to severe bending (i.e., deflection) and, in some cases, failure at the PC distributor, because of the relatively low yield strength of the high thermal conductivity components in the PC distributor. Since the introduction of the mid-lance PC distributor (i.e., at least in the 1980s, and possibly earlier), no effective solutions to the bending and/or failure problems have been implemented. Prior art post-combustion lances typically bend after a relatively short period in service, requiring relatively frequent replacement of the PC distributor.

Previous attempts to address this problem included the development of external removable protective sleeves which are put on new and refurbished PC distributor equipped lances to protect the lances during shipping to the user's facilities. However, the protective sleeves must be removed before the lance is put into service. In practice, sleeves are typically removed prior to completion of the unloading and installation of the lance. As a result, the lance is often bent subsequent to the protective sleeve removal, i.e., during the completion of installation, while in service, or while the lance is loaded back onto the truck for return repair at the end of its service life.

As is well known in the prior art, post-combustion lances may also include one or more spacers21′, to maintain proper alignment of the tubes when the lance is being assembled. The spacers21′ also serve to stiffen the lance to a small extent, however, it appears that they generally have only a limited, localized effect in this regard. For instance, another prior art post-combustion lance10′ including spacers21′ is illustrated inFIGS. 1C-1H. (The balance of the drawings disclose the invention herein.) The reference numerals relating to the prior art lance illustrated inFIGS. 1C-1Hare designated by prime (′) symbols for the sake of convenience.

As can be seen, for example, inFIG. 1D, in the prior art, spacers21′ are mounted on a lower intermediate element31′. In general, the typical spacers21′ are formed as elongate ridges on an outer surface of a tube element. The spacers21′ preferably are relatively narrow (FIG. 1F), and spaced apart from each other around an outer surface33′ of the lower intermediate element31′ (FIG. 1F).

Additional spacers21′ are shown inFIG. 1E. For instance, spacers21A′,21B′ are mounted on an upper inner tube26′ (FIG. 1E). Additional spacers21C′,21D′ are positioned on a slip joint part26A′ of the upper inner tube26′ (FIG. 1E). Also, and as can be seen inFIG. 1E, spacers21E′,21F′ are mounted on an upper intermediate element29′. The PC distributor18′ is also illustrated inFIG. 1E, and additional spacers21G′,21H′, mounted on the lower intermediate element31′, can also be seen inFIG. 1E.

FIG. 1Ealso shows that a first internal element23′ of the PC distributor18′ is welded to a lower inner tube34′ and positioned adjacent to a second internal element38′. As can be seen inFIG. 1E, the post-combustion lance10′ also includes an o-ring gland35′ mounted in the first internal element23′, to enable movement of the first internal element23′ and the second internal element38′ relative to each other generally axially (i.e., in a direction substantially parallel to the axis27′). As can be seen inFIG. 1E, the o-ring gland35′ preferably includes a number of o-rings37′. Those skilled in the art will appreciate that, in order for such movement to take place, a similar arrangement (i.e., an o-ring gland, to permit substantially axial relative movement of adjacent elements) is typically also included at the upper end of the upper portion22′. This other o-ring gland or similar arrangement (not shown) typically is positioned near a manifold (not shown) through which oxygen (and other gases, as required) and water are provided to the lance. As is well known in the art, the o-ring glands are needed in order to permit expansion and/or contraction of various elements in the lance10′, due to extreme temperature differences.

As noted above, because the PC distributor tends to be relatively weak (i.e., because it is primarily made of copper), the lance10′ tends to bend at the distributor. In general, the lower portion24′ tends to move downwardly (under the influence of gravity), in the direction indicated by arrow “J” inFIG. 1C. FromFIGS. 1C and 1E, however, it can be seen that the o-ring gland35′ also provides a relatively weaker area in the lance10′, about which the lower portion34′ tends to bend downwardly. In effect, the positioning of the o-ring gland35′ in the PC distributor18′ tends to undermine the overall structural integrity of the lance10′.

For example, as can be seen inFIGS. 1F-1H, spacers21J′ and21K′ are positioned on an outer surface39′ of the lower inner tube34′. However, each of the spacers21J′ and21K′ has an outer region41′ that faces an inner surface43′ of the lower intermediate element31′, i.e., the outer region41′ is positioned opposite to the inner surface43′. The outer region41′ and the inner surface43′ are separated by a gap45′. Similarly, spacers21L′ and21M′ are mounted on the outer surface33′ of the lower intermediate element31′. Each of the spacers21L′,21M′ includes an outer region47′ that faces an inner surface49′ of an exterior tube51′. In each case, the outer region47′ is spaced apart from the inner surface49′ by a gap53′ (FIG. 1H).

It can be seen, therefore, that the spacers of the prior art generally do not provide sufficient support to the body, and that positioning one or more of the o-ring glands at or near the distributor tends to weaken the lance.

SUMMARY OF THE INVENTION

For the foregoing reasons, there is a need for an internal support assembly for a post-combustion lance, and a post-combustion lance including same.

In its broad aspect, the invention provides a post-combustion lance for directing a gas at least partially therethrough. The post-combustion lance includes a body extending between an upstream end and a downstream end of the lance, the downstream end having a primary tip through which a first part of the gas exits the lance. The body includes upper and lower portions and a post-combustion distributor mounted between the upper and lower portions at a predetermined distance from the primary tip. The distributor includes a number of ports through which a second part of the gas exits the lance. The upper and lower portions are located upstream and downstream respectively relative to the distributor. The lance also includes an internal support assembly for supporting the body. The internal support assembly includes an internal tube positioned inside the body and at least partially engaged with the lower portion thereof. Also, the internal support assembly is at least partially engaged with the upper portion of the body so that the internal support assembly supports the body upstream and downstream relative to the distributor. The lance also includes a lower o-ring gland positioned downstream relative to the distributor to permit movement of at least part of the internal support assembly and at least part of the body relative to each other due to thermal expansion. In addition, the lance includes an upper o-ring gland positioned upstream relative to the lower o-ring gland, to permit movement of at least part of the internal support assembly and at least part of the body relative to each other due to thermal expansion.

In another of its aspects, the invention provides a post-combustion lance having a body at least partially defined by an axis thereof and extending between an upstream end and a downstream end of the lance, the upstream end being adapted to receive the gas, and the downstream end comprising a primary tip through which a first part of the gas exits the lance. The body includes upper and lower portions and a post-combustion distributor mounted between the upper and lower portions at a predetermined distance from the primary tip, the distributor having a number of ports through which a second part of the gas exits the lance, the upper and lower portions being located upstream and downstream respectively relative to the distributor. The body also includes an upper inner tube positioned at least partially upstream from the distributor, a lower inner tube positioned at least partially downstream from the distributor, and a connecting tube for directing the gas to the upper portion. In addition, the lance includes an internal support assembly for supporting the body, the internal support assembly including an internal tube positioned inside the body and engaged with at least a part of the lower inner tube, one or more collars positioned between the internal tube and the upper portion, so that the internal support assembly supports the body upstream and downstream relative to the distributor. The lance also has a lower o-ring gland positioned proximal to the lower portion, to permit movement of the internal tube and the primary tip relative to each other due to thermal expansion at least partially in an axial direction substantially parallel to the axis, and an upper o-ring gland positioned proximal to the upper portion, to permit movement of the upper inner tube and the connecting tube relative to each other due to thermal expansion at least partially in the axial direction.

In another aspect, the invention provides a post-combustion lance including a body at least partially defined by an axis thereof and extending between an upstream end and a downstream end of the lance, the upstream end being adapted to receive the gas, and the downstream end including a primary tip through which a first part of the gas exits the lance. The body includes upper and lower portions and a post-combustion distributor mounted between the upper and lower portions at a predetermined distance from the primary tip, the distributor including a number of ports through which a second part of the gas exits the lance, the upper and lower portions being located upstream and downstream respectively relative to the distributor. The distributor additionally includes a distributor tube extending upstream relative to the ports. The body also includes an upper inner tube positioned at least partially upstream from the distributor, an adaptor secured to the upper inner tube and engageable with the distributor tube, and a lower inner tube positioned at least partially downstream from the distributor. The lance also includes an internal support assembly for supporting the body, the internal support assembly having an internal tube positioned inside the body and engaged with the lower inner tube at least partially downstream relative to the distributor and the upper inner tube at least partially upstream relative to the distributor. The lance additionally includes a lower o-ring gland positioned proximal to the lower portion, to permit movement of the lower inner tube and the primary tip relative to each other due to thermal expansion at least partially in an axial direction substantially parallel to the axis, and an upper o-ring gland positioned on the adaptor for engagement with the distributor tube, to permit movement of the upper inner tube and the distributor tube relative to each other due to thermal expansion at least partially in the axial direction.

DETAILED DESCRIPTION

To simplify the description, the reference numerals used previously inFIGS. 1A and 1Bwill be used again in connection with the description of the invention hereinafter, except that each such reference numeral is raised by 100 (or by whole number multiples thereof, as the case may be), where the parts described correspond to parts described above.

Reference is first made toFIGS. 2A-2Eand6A-6C to describe an embodiment of a post-combustion lance in accordance with the invention indicated generally by the numeral140. The post-combustion lance140is for directing a gas (not shown) at least partially therethrough. In one embodiment, the post-combustion lance140includes a body120extending between an upstream end112and a downstream end114of the lance140. The upstream end112is adapted to receive the gas, and the downstream end114includes a primary tip116through which a first part of the gas exits the lance140. The body120also includes upper and lower portions122,124and a post-combustion distributor118mounted therebetween at a predetermined distance from the primary tip116. The distributor118includes a plurality of ports119through which a second part of the gas exits the lance140. In one embodiment, the lance140preferably includes an upper inner tube126positioned at least partially upstream from the distributor118and attached to the upper portion122, and a lower inner tube134positioned at least partially downstream from the distributor118and attached to the lower portion124. Preferably, the lance140also includes an internal support assembly142for supporting the body120, as will be described. In one embodiment, the internal support assembly142preferably includes an internal tube144positioned inside the body120and also positioned at least partially upstream relative to the lower inner tube134. The internal tube144preferably is engaged with the lower inner tube144, as will also be described. The internal support assembly142also includes one or more collars146positioned between the upper inner tube126and the internal tube144to support the internal tube144in a predetermined position coaxial with the body120so that the internal tube144resists deflection of the body120.

An embodiment of the collar146of the invention is shown inFIGS. 6A-6C. Preferably, each collar146is secured to the internal tube144. For example, the collar146is welded to the internal tube144, in one embodiment. Also, it is preferred that the collar146(i.e., at least one collar146) is attached to the upper inner tube126.

As can be seen inFIGS. 2B and 2C, a downstream portion148of the internal tube144engages an upstream portion150of the lower inner tube134. This enables the internal tube144to resist deflection of the body120, and in particular, to resist transverse deflection of the body120.

The upper inner tube126is securely mounted to the upper portion122. Also, the lower inner tube134is securely mounted to the lower portion124. The manner in which the upper and lower inner tubes126,134are secured to the upper and lower portions122,124is well known in the art, and therefore does not need to be described. As shown inFIGS. 2A-2C, and as will be described, the internal support assembly142is connected with each of the upper and lower inner tubes126,134respectively, and thereby also indirectly connected with the upper and lower portions122,124.

In one embodiment, an outer wall152of the internal tube144in the downstream portion148thereof engages an inner wall154of the lower inner tube134in the upstream portion150thereof so that the internal tube144supports the body120(FIG. 2D). Preferably, the downstream portion148of the internal tube144and the upstream portion150of the lower inner tube134are slidingly engaged with each other, i.e., longitudinal sliding movement of the internal tube144relative to the lower inner tube134(and vice versa) is permitted. However, bending (i.e., deflection) of the lower inner tube in an at least partially transverse direction is resisted by the internal tube144, due to the close engagement of the internal tube144and the lower inner tube134.

As can be seen inFIGS. 2A-2C, the lance140preferably includes a plurality of collars146a,146bin which each collar is secured to the outer wall152of the internal tube144. It is preferred that the collars146are attached or secured to an upstream portion156of the internal tube144, i.e., a portion of the internal tube upstream relative to the ports119. Preferably, one of the collars (in the drawings, the collar146b) is also attached to an inner wall158of the upper inner tube126, to position the internal tube144substantially coaxially with the body120. The axes127of the upper and lower portions are shown inFIG. 2A. For example, it is preferred that each collar146a,146bis welded to the outer wall152of the internal tube144. As will be described, in one embodiment, only one of the collars (e.g., the collar146b, as shown inFIG. 2C) preferably is attached to the inner wall158of the upper inner tube126(FIGS. 2B,2C). As can be seen inFIGS. 2B and 2C, where the collar146bis attached (e.g., by welding) to the inner wall158, the other collar146apreferably engages the inner wall158.

Accordingly, and as noted above, it can be seen that the upstream portion156of the internal tube144is indirectly connected (i.e., via the engagement and/or attachment of the collars to the upper inner tube) with the upper portion122of the body120, and the downstream portion148of the internal tube144is indirectly connected (i.e., via the engagement of the downstream portion of the internal tube with the upstream portion of the lower inner tube) with the lower portion124of the body120. Because of the indirect connection of the internal tube's upstream portion156and downstream portion148with the upper and lower portions122,124respectively, the internal support assembly142resists deflection o the body, particularly deflection thereof in an at least partially transverse direction.

As can be seen inFIGS. 2A-2C, the upper inner tube126preferably includes an upstream portion128proximal to the upstream end112. The upstream portion128preferably is substantially cylindrical, and has outer and inner diameters defined by outer and inner walls161,162(FIG. 2B). The upper inner tube126preferably also includes a downstream portion130located proximal to the distributor118. The downstream portion130preferably has an outer diameter defined by an outer wall165substantially larger than the outer diameter of the upstream portion128and an inner diameter defined by the inner wall158substantially larger than the inner diameter of the upstream portion128(FIG. 2B). In addition, the upper inner tube126preferably also includes a connecting portion132connecting the upstream and downstream portions128,130. The internal tube144preferably has an outer diameter defined by the outer wall152thereof, which is substantially smaller than the inner diameter of the downstream portion130. An annulus172is defined accordingly between the internal tube144and the downstream portion130(FIGS. 2B,2C). Preferably, the annulus172is in fluid communication with the ports119(FIGS. 2B,2C,2C).

In addition, and as can be seen inFIGS. 2C,6A,6B, and6C, each collar146preferably includes one or more apertures174to permit the second part of the gas to flow therethrough to the ports119.

As noted above, the upper portion122and the lower portion124of the lance body120preferably are made of steel. The distributor118typically includes materials with relatively good heat conductivity, e.g., copper.

The internal support assembly142may be made of any suitable materials. For example, the internal tube144and the collars146may be made of steel. As shown inFIG. 2E, in one embodiment, the support assembly142preferably includes the internal tube144and two collars146a,146b.

As described above, the internal tube144is positionable inside the body120and at least partially upstream relative to the lower inner tube134. Preferably, the internal tube144is engageable with the lower inner tube134. Also, the internal support assembly142includes one or more collars146which are securable to the internal tube144and positionable between the upper inner tube126and the internal tube144, to maintain the internal tube144in a predetermined position relative to the upper inner tube126and the lower inner tube134. Preferably, the internal tube144is positioned coaxial with the upper and lower inner tubes126,134, to facilitate flow of the gas through the lance140. As well, and as described above, the internal tube144is positioned to resist deflection of the body120.

In use, the lance140is supported at or close to the upstream end112. Because only the upper portion is directly supported while the lance is in operation, gravity urges the lower portion124of the lance downwardly, as indicated by arrow “E” inFIG. 2B. The downwardly directed force is substantially transverse (or at least partially transverse) to the body. However, as can be seen inFIG. 2B, the internal tube144resists deflection of the lance body because the internal tube144is engaged with the lower inner tube at the downstream portion148thereof, and the internal tube144is also engaged with the upper inner tube126, i.e., via the collars146a,146b.

The internal support assembly142is assembled by securing the collars146to the outer wall152of the internal tube144(FIG. 2E). The internal support assembly142is positioned in the body120as shown inFIGS. 2A-2C. Preferably, the internal tube144is mounted in the body120substantially coaxial with the body120, so that the internal tube144resists deflection of the body. The gas as initially introduced into the lance140is represented by arrow “J” inFIGS. 2A,2B, and2C. Part of the gas (represented by arrows “K1”, “K1”, “K3”, “K4”, “K5”, and “K6” inFIGS. 2C and 2D) is directed through the apertures174in the collars146a,146band along the annulus174to the port119, where the part of the gas exits the lance140. The other part of the gas (represented by arrows “L1”, “L2”, “L3” inFIGS. 2A,2B,2C, and2D) is directed inside the internal tube144and through the lower inner tube134to the tip116, where it exits the lance140.

Additional embodiments of the invention are shown inFIGS. 3A-5Cand7A-8B. InFIGS. 3A-5Cand7A-8B, elements are numbered so as to correspond to like elements shown inFIGS. 2A-2Eand6A-6C.

It will be understood that the internal support assembly142of the invention may be retrofitted into an existing post-combustion lance. The steps of the method of retrofitting the internal support assembly142in a prior art post-combustion lance are shown inFIGS. 7A-7E.

As shown inFIG. 7A, a prior art lance210is cut using any suitable means for doing so at a suitable location on the lance body, the suitable location preferably being upstream relative to the distributor218. For example, the body may be cut by a cutting torch. The cut defines upper and lower cut portions206,208of the lance body220.

Preferably, the lower cut portion208is then removed from the upper cut portion206, as indicated by arrows “F” inFIG. 7A. The upper cut portion206is shown inFIG. 7B.

InFIG. 7C, the next step is shown. In this step, the internal support assembly142is moved into the upper cut portion206, in the direction indicated by arrow “G” inFIG. 7C. The internal support assembly142preferably is formed so that the collars146are slidingly receivable in the downstream portion230of the upper inner tube226.

Once a predetermined portion275of the internal support assembly142is positioned in the downstream portion230of the upper inner tube226, one of the collars146is attached to the upper inner tube226. For example, it is preferred that the collar146bis welded to the upper inner tube226, at the location identified by reference numeral276inFIG. 7D.

InFIG. 7E, the lower cut portion208(or a replacement thereof, as described below) is slidingly engaged with the internal tube144as the lower cut portion208is moved in the direction indicated by arrows “H” inFIG. 7E. As can be seen inFIG. 7E, the lower inner tube236in the lower cut portion208is slidingly engaged with the downstream portion148of the internal tube144as the lower cut portion208is moved in the direction indicated by arrows “H1” and “H2”. Once the lower cut portion208abuts the upper cut portion206, the lower cut portion208is in position.

Finally, the lower cut portion208is attached to the upper cut portion206of the lance body220, using any suitable means. For instance, the lower cut portion208may be welded to the upper cut portion206. The result is a post-combustion lance240of the invention, as shown inFIG. 7E.

Those skilled in the art would appreciate that a new lower cut portion (i.e., rather than the lower cut portion which was removed) may be attached to the upper cut portion. Using a new portion may be preferable if, for example, the old portion was deformed.

FIGS. 3A-3Cdisclose another embodiment of the post-combustion lance340of the invention in which an internal support assembly342includes an internal tube344which preferably has an upstream portion384engaged with the upstream portion328of the upper inner tube326. Preferably, the internal tube344additionally includes one or more apertures386positioned at least partially upstream relative to the distributor118to permit the second part of the gas to flow to an annulus372from the upstream portion of the upper inner tube326.

As can be seen inFIG. 3A, the post-combustion lance340includes a body320extending between an upstream end312and a downstream end314. Gas is receivable at the upstream end, and a first part of the gas exits the lance340via a primary tip316positioned at the downstream end314. A distributor318mounted between the upstream and downstream ends312,314is positioned between upper and lower portions322,324of the body.

The upstream portion384of the internal tube344preferably extends further in an upstream direction (i.e., upstream beyond the downstream portion330and the connecting portion332of the upper inner tube326) to engage the upstream portion328of the upper inner tube326. The advantage of this embodiment (as compared to the lance140, described above) is that it provides an additional area of engagement (i.e., as compared to lances140and240) between the internal tube and the upper inner tube. In one embodiment, the collars346are positioned between the internal tube344and the upper inner tube326. Because the upper inner tube326is secured to the upper portion322, this means that the internal tube344is indirectly connected with the upper portion322via the collars346, and also via the engagement of the upstream portion384of the internal tube344with the upstream portion328of the upper inner tube326. A downstream portion348of the internal tube344is also engaged with an upstream portion350of the lower inner tube336. Accordingly, the internal support assembly342resists deflection of the body320.

Preferably, the upstream portion384of the internal tube344is slidingly engaged with the upstream portion328, and the downstream portion348of the internal tube344is slidingly engaged with the upstream portion350of the lower inner tube336.

As shown inFIGS. 3A-3C, because of the engagement of the upstream portion384of the internal tube344with the upstream portion328of the upper inner tube326, the apertures386are provided in the internal tube344. An annulus372is defined between an outer wall352of the internal tube344and the connecting and downstream portions332,330of the upper inner tube326. The annulus372is in fluid communication with the ports319via apertures374in the collars346.

Another embodiment of the post-combustion lance440of the invention is disclosed inFIGS. 4A-4C. The post-combustion lance440includes a body420extending between an upstream end412and a downstream end414of the lance440, the upstream end412being adapted to receive the gas. The downstream end414includes a primary tip416through which a first part of the gas exits the lance440. The body420includes upper and lower portions422,424and a post-combustion distributor418mounted therebetween at a predetermined distance from the primary tip416. The lance440preferably also includes an upper inner tube426positioned at least partially upstream from the distributor418(FIG. 4B) and attached to the upper portion422. In addition, the lance440includes an internal support assembly442for supporting the body420(FIGS. 4A-4C). In one embodiment, the internal support assembly442includes an internal tube444extending between a downstream end487thereof positioned proximal to the downstream end414of the lance440, and to an upstream end488of the internal tube444positioned at least partially upstream relative to the ports419of the distributor418. Preferably, the internal support assembly442additionally includes one or more collars446secured to the internal tube444and positioned between the upper inner tube426and the internal tube444, to support the internal tube444in a predetermined position substantially coaxial with the upper inner tube426so that the internal tube444resists deflection of the body420.

As can be seen inFIGS. 4B and 4C, the lance440does not include a lower inner tube in which a downstream portion of the internal tube444is slidingly engageable. The internal tube444preferably is mounted to the lower portion424at the downstream end487of the internal tube444, using any suitable means. For example, the internal tube444may be welded to the lower portion424at any suitable location(s) thereon, i.e., the internal tube444may be welded to the lower portion424at the downstream end487.

InFIGS. 5A-5C, another embodiment of the post-combustion lance540of the invention is shown. The post-combustion lance540includes a body520extending between an upstream end512and a downstream end514of the lance540, the upstream end512being adapted to receive the gas. The downstream end514includes a primary tip516through which a first part of the gas exits the lance540. The body520includes upper and lower portions522,524and a post-combustion distributor518mounted therebetween at a predetermined distance from the primary tip516. The lance540preferably also includes an upper inner tube526positioned at least partially upstream from the distributor518(FIG. 5B) and attached to the upper portion522. In addition, the lance540includes an internal support assembly542for supporting the body520. In one embodiment, the internal support assembly542includes an internal tube544extending between a downstream end587thereof positioned proximal to the downstream end514of the lance540, and to an upstream end588of the internal tube444.

As can be seen inFIGS. 5A-5C, in one embodiment, an upstream portion584preferably is engaged with an upstream portion528of the upper inner tube526. Preferably, the internal support assembly542additionally includes one or more collars546secured to the internal tube544and positioned between the upper inner tube526and the internal tube544, to support the internal tube544in a predetermined position substantially coaxial with the body520so that the internal tube544resists deflection of the body520. The lance540does not include a lower inner tube in which a downstream portion of the internal tube544is slidingly engageable. The internal tube544preferably is engaged to the lower portion524of the internal tube544, using any suitable means.

As shown inFIGS. 5A-5C, the internal tube544preferably also includes one or more apertures586. The internal tube544is positioned in the body520so that the apertures586are at least partially upstream relative to the ports519in the distributor518.

Another alternative embodiment of the post-combustion lance640of the invention is disclosed inFIG. 8A. As can be seen inFIG. 8A, the lance640is similar to the lance320disclosed inFIGS. 3A-3C, except that the lance640does not include elements corresponding to the collars346in the lance340.

In the lance640, the internal support assembly642includes the internal tube644, but does not include collars. As can be seen inFIG. 8A, the internal tube644includes an upstream portion656which is engaged in the upstream portion628of the upper inner tube626. Similarly, a downstream portion648of the internal tube644is engaged with an upstream portion650of the lower inner tube634. In this embodiment, the internal tube is secured to either the upper inner tube626or the lower inner tube634, or both, in order to maintain the internal tube644in position. The internal tube644supports the body620of the lance, because the internal tube644is engaged with each of the upper inner tube626and the lower inner tube634, at the internal tube's upstream and downstream portions656,648respectively. An annulus672in fluid communication with the ports619of the distributor618is defined between the internal tube644and the downstream portion630of the upper inner tube626. The internal tube644includes apertures686to permit the second part of the gas to flow from the upstream portion628of the upper inner tube626to the annulus672.

Another alternative embodiment of the post-combustion lance740of the invention is disclosed inFIG. 8B. The lance740is similar to the lance640, except that the lance740does not include an element corresponding to the lower inner tube of the lance640. The internal tube744includes a downstream end787which is secured to the lower portion724of the lance body720by any suitable means. The internal tube744also includes an upstream portion756which is engaged with an upstream portion728of the upper inner tube726. Accordingly, the internal tube744supports the body720.

An annulus772in fluid communication with the ports719of the distributor718is defined between the internal tube744and a downstream portion730of the upper inner tube726. The internal tube744includes apertures786to permit the second part of the gas to flow from the upstream portion728to the annulus772which is defined between the internal tube744and a downstream portion730of the upper inner tube726.

Another alternative embodiment of the post-combustion lance840of the invention is illustrated inFIGS. 9A-9D. The post-combustion lance840is for directing a gas at least partially therethrough. As can be seen inFIG. 9A, the post-combustion lance840preferably includes a body820extending between an upstream end812and a downstream end814of the lance840. The downstream end814preferably has a primary tip816, through which a first part of the gas exits the lance. It is also preferred that the body820includes upper and lower portions822,824, and a post-combustion distributor818mounted between the upper and lower portions822,824at a predetermined distance “Y” from the primary tip816. The distributor includes a number of ports819(FIG. 9D) through which a second part of the gas exits the lance. As can be seen inFIG. 9A, the upper and lower portions822,824are located upstream and downstream respectively relative to the distributor818. Preferably, the lance840also includes an internal support assembly842for supporting the body820. The internal support assembly842preferably includes an internal tube844positioned inside the body820and at least partially engaged with the lower portion824thereof. The internal support assembly842preferably is at least partially engaged with the upper portion822of the body, so that the internal support assembly842supports the body820both upstream and downstream relative to the distributor818, as will be described. In one embodiment, the lance840preferably also includes a lower o-ring gland871positioned downstream relative to the distributor818to permit movement of at least part of the internal support assembly842and at least part of the body820relative to each other due to thermal expansion, and an upper o-ring gland857positioned upstream relative to the lower o-ring gland871, to permit movement of at least part of the internal support assembly842and at least part of the body820relative to each other due to thermal expansion.

For the purposes hereof, it will be understood that the terms “upstream” and “downstream” are to be understood as relative to the direction of flow of the gas through the lance, i.e., such flow generally being from the upstream end toward the downstream end of the lance.

As can be seen inFIG. 9A, the body820preferably is at least partially defined by an axis827thereof. As noted above, the body820extends between the upstream and downstream ends812,814of the lance840. The upstream end812is adapted to receive the gas, and the downstream end814preferably includes the primary tip816, through which the first part of the gas exits the lance840, as will be described. The body820preferably includes the upper and lower portions822,824and the post-combustion distributor818mounted therebetween at the predetermined distance from the primary tip816. As can be seen inFIGS. 9A and 9D, the body820preferably also includes an upper inner tube826positioned at least partially upstream from the distributor818, a lower inner tube834positioned at least partially downstream from the distributor818, and a connecting tube855for directing the gas to the upper portion822. Preferably, the lance840also includes the internal support assembly842for supporting the body820, the internal support assembly842having the internal tube844positioned inside the body820and engaged with at least a part of the lower inner tube834. It is also preferred that the internal support assembly842includes one or more collars846positioned between the upper inner tube826and the internal tube844, to support the internal tube844in a preselected position coaxial with the body820so that the internal tube844resists deflection of the body820. As will be described, the collars846are positioned between the internal tube844and the upper portion822, so that the internal support assembly842supports the body820both upstream and downstream relative to the distributor818. In one embodiment, the internal support assembly842preferably also includes the lower o-ring gland871positioned proximal to the lower portion824, to permit movement of the internal tube844and the primary tip816relative to each other due to thermal expansion at least partially in an axial direction substantially parallel to the axis827, and the upper o-ring gland857positioned proximal to the upper portion822, to permit movement of the upper inner tube826and the connecting tube855relative to each other due to thermal expansion at least partially in the axial direction. Preferably, the collars846include apertures874therein to permit the gas to flow therethrough.

As described above, the upper portion822is located upstream from the distributor818, and the lower portion824is located downstream from the distributor818. Certain elements of the body may not necessarily be located entirely in the upper portion, or entirely in the lower portion. It can be seen inFIG. 9Athat the upper inner tube826is located at least partially in the upper portion824, and the lower inner tube834is located at least partially in the lower portion824.

As can be seen inFIG. 9B, the primary tip816preferably includes a primary nozzle859with orifices860therein, through which the first part of the gas is directed. It is also preferred that the primary tip816includes a tip tube863. Preferably, the nozzle859is secured to the tip tube863, which is formed and positioned so that the tip tube portion863is slidably engaged with a downstream portion848of the internal tube844. The tip tube863directs the first part of the gas to the primary tip814, i.e., the tip tube863directs the first part of the gas to the nozzle859. The tip tube863preferably is substantially coaxial with the body820, and the internal tube844, so that the internal tube and the tip tube provide a central channel817through which the first part of the gas is directed. The tip tube863and the lower inner tube834include respective engaged parts869,873along which they are engaged. It is preferred that an exterior surface864of the tip tube863slidably engages an interior surface867of the lower inner tube834(FIG. 9B).

The positioning of the tip tube partially inside the lower inner tube834permits thermal expansion of the tip tube863and/or the lower inner tube834substantially in the axial direction, i.e., without imposing substantial stresses on those elements due to thermal expansion. Due to the generally axial movement of the engaged parts869,873, significant stress due to thermal expansion does not accrue in the tip tube863or in the lower inner tube834.

In one embodiment, the lower o-ring gland871preferably is mounted on the tip tube exterior surface864. Those skilled in the art will appreciate that the o-ring gland871preferably includes a number of o-rings, designated868A-868C inFIG. 9Bfor convenience.

It will be understood that the lower o-ring gland871may include any suitable number of o-rings. Those skilled in the art will appreciate that the specific details of the o-rings and the o-ring gland will be determined, in each case, by taking into account a number of factors specific to a particular installation.

Those skilled in the art would appreciate that thermal expansion of the elements of the lance can be significant, and is taken into account when the lance is constructed. The temperatures in a converter, outside the lance, may be between about 1300° C. and about 1750° C. The lance preferably is cooled by water, as will be described. Accordingly, when the lance is introduced into the converter, it is heated rapidly, and the materials thereof expand accordingly. However, when the lance is removed, it is allowed to cool.

For the purposes hereof, it is understood that the term “thermal expansion” refers both to the expansion of a material due to an increase in its temperature and to the contraction of the material. As is well known in the art, because different materials in the lance have different thermal-expansion coefficients, they expand at different rates. In addition, due to the cooling effect of the water circulated through the lance (and the movement of the lance in and out of the converter), different parts of the lance are heated (or cooled, as the case may be) at different rates.

As can be seen, for example, inFIG. 9B, the first part of the gas (e.g., oxygen) is directed through the internal tube844and exits the lance via the orifice860of the nozzle859. The direction of movement of the oxygen through the central channel817is indicated by arrows “M1” and “M2” inFIG. 9B. (It will be understood that only one orifice860is shown inFIG. 9Bfor clarity of illustration.) In one embodiment, the lance840preferably includes an outer cavity825(located between an exterior tube851and a lower intermediate element831) and an inner cavity877(located between the lower intermediate element831, on one side thereof, and the internal tube844and the tip tube863, on the other side thereof). Those skilled in the art will appreciate that, to cool the lance840, water is circulated through the inner and outer cavities877,825, as will be described. For instance, in one embodiment (illustrated inFIG. 9B), water is directed through the inner cavity877in the direction indicated by arrow “N1”, and the water is also directed through the outer cavity825generally in the direction indicated by arrow “O1”.

The thermal expansion of the components of the lance840results in relative movement of certain parts thereof substantially in the axial direction, i.e., substantially in a direction parallel to the axis827of the lance840. For instance, when the lance840is initially positioned in the converter, although the lance840is rapidly heated, the temperature of the lower portion824initially increases more rapidly than the temperature of the upper portion822. Due to differences in temperature at different parts of the lance and/or differences in materials, the engaged part869of the tip tube863moves relative to the engaged part873of the lower inner tube834, and/or vice versa, i.e., because of thermal expansion. As can be seen inFIG. 9B, the relative movement of one of the engaged parts869,873relative to the other (and/or of both of the engaged parts869,873relative to each other, as the case may be) is in the axial direction. Such movement is schematically represented inFIG. 9Bby arrows “P1” and “P2”.

Those skilled in the art will appreciate that the lower o-ring gland871accommodates the axial movement of the engaged parts869,873due to thermal expansion, but also provides a seal between the engaged parts869,873, to substantially prevent the water flowing through the inner cavity877from entering the central channel817.

The upper o-ring gland857is illustrated inFIG. 9C. The upper inner tube826is positioned coaxially with the axis827and with the connecting tube855. As can be seen inFIG. 9C, the connecting tube855includes an engaged part879and the upper inner tube826includes an engaged part881, and the engaged parts879,881preferably are engageable with each other. In particular, it will be understood that the engaged parts879,881are slidingly engageable with each other. The connecting tube855includes an interior surface895, and the upper inner tube826includes an exterior surface897. As indicated inFIG. 9C, the interior surface895and the exterior surface897preferably are slidingly engaged with each other. The oxygen flows in the lance along a central channel883defined by the connector tube855and the upper inner tube826as indicated by arrow “M3”.

The body of the lance840preferably also includes an upper intermediate element829. An inner cavity885is located between and defined by the upper intermediate element829, on one side thereof, and the connecting tube855and the upper inner tube826, on the other side thereof. Similarly, an outer cavity888is located between the upper intermediate element829and the exterior tube851. It will be understood that the inner cavity885of the upper portion is in fluid communication with the inner cavity877in the lower portion, and the outer cavity888of the upper portion is also in fluid communication with the outer cavity825in the lower portion. InFIG. 9C, the directions of flow of the water directed through the cavities, to cool the lance840, are indicated by arrows “N2” and “O2”.

As can also be seen inFIG. 9C, in one embodiment, the o-ring gland857preferably includes three o-rings, identified inFIG. 9Cas868D-868F. (It will be understood that the o-ring gland857may include any suitable number of o-rings.) The engaged parts879,881are movable relative to each other in the axial direction, as indicated by arrows “P3” and “P4” inFIG. 9C. For the reasons described above, one or both of the engaged parts879,881may move relative to the other, due to thermal expansion. The movement preferably is in the form of sliding engagement of the engaged parts879,881with each other, i.e., one or both of the engaged parts slidingly engaging the other. The o-ring gland857permits such movement, and also provides a seal to substantially prevent water in the inner cavity877from leaking into the central channel883.

As can be seen inFIG. 9D, the second part of the gas exits the lance840via the ports. InFIG. 9D, such flow of the second part of the gas is represented by arrows “M4”. The first part of the gas is represented by arrow “M5”.

From the foregoing, it can be seen that the body820includes substantially all of the lance840, excluding the internal support assembly842. For instance, the body820preferably includes the upper inner tube826and the lower inner tube834, as well as the exterior tube851, the distributor818, the lower intermediate element831, the tip tube863, and the upper intermediate element829. It will be understood that, in one embodiment, the exterior tube851preferably is not a continuous physical element extending between the upstream end and the downstream end of the lance840, but instead is divided into two portions, i.e., one located upstream from the distributor818, and the other located downstream relative thereto.

From the foregoing, it can be seen that, in the lance840, the lower and upper o-ring glands871,857are positioned at the lower and upper ends of the lance, i.e., the o-ring glands871,857are positioned at predetermined distances Q1, Q2(FIG. 9A) apart from the distributor818. Also, and as can be seen inFIG. 9D, the lance840preferably does not include an o-ring gland positioned at, or proximal to, the distributor818. The o-ring glands871,857are positioned generally proximal to the lower and upper ends of the lance respectively, and in particular, the lance840does not include an o-ring gland proximal to the distributor.

In one embodiment, each of the collars846preferably is secured to the internal tube844. Preferably, the collars846are secured to the internal tube844by any suitable means. As can be seen inFIG. 9A, the collars846preferably are located proximal to the upper portion. It is also preferred that each of the collars846is engageable with the upper inner tube. Preferably, the collars846are positioned relative to the upper inner tube826for sliding engagement therewith, i.e., permitting movement of the internal tube844and/or the upper inner tube826relative to each other, due to thermal expansion, in substantially the axial direction. At the same time, however, via the collars846, the internal tube844supports the upper portion of the body so that the internal tube844resists deflection of the body820.

As illustrated inFIG. 9A, and as described above, it is preferred that the internal tube844is engaged with the lower inner tube834. A portion of the internal tube844preferably is positioned inside the lower inner tube834for slidable engagement therewith, i.e., to permit movement of the internal tube844and/or the lower inner tube834relative to each other due to thermal expansion. The lower inner tube834and the internal tube844are engaged along a length of the internal tube844identified for convenience as “X” inFIG. 9A. The movement of the internal tube834and/or the internal tube844relative to each other due to thermal expansion is substantially in the axial direction, i.e., in the directions indicated by arrows “P5” and “P6” inFIG. 9D.

In effect, the body820is supported above and below the distributor818by the internal support assembly842. Also, and as can be seen inFIGS. 9A and 9D, the internal tube844also is partly located proximal to the distributor818(i.e., the internal tube844extends between its upstream and downstream ends), so that the internal support assembly842supports the distributor818substantially directly.

As shown inFIG. 9A, the internal support assembly842extends between an upstream end801thereof and a downstream end802thereof. At the upstream end801, the collar846positioned furthest upstream engages the upper inner tube826. At the downstream end802, the internal tube844terminates. The upstream end801and the downstream end802are located upstream and downstream respectively relative to the distributor818. Accordingly, the support provided by the internal support assembly842to the body820is a “bridging” effect, i.e., the internal support assembly842spans the distributor818between the upstream end801located upstream relative to the distributor818and the downstream end802, located downstream thereto. Also, and as can be seen inFIG. 9A, the o-ring glands871,857are positioned outside the internal support assembly842, i.e., outside the “bridging” portion of the lance840. As is known, the o-rings871,857are relatively weak, and because they are located outside the bridging portion, they have virtually no effect on the structural strength of the lance840overall.

Those skilled in the art will also appreciate that, because of the sliding engagement of the internal tube844at its lower and upper ends (i.e., partly via the collars846), thermal expansion is accommodated.

The lance840preferably includes spacers821(FIG. 9B). It will be understood that, although the spacers821may provide support to the lance, any such support is localized (i.e., the extent of the support provided by the spacers is generally limited to the immediate vicinity thereof). In particular, it can be seen inFIGS. 9A and 9Bthat the support provided by the spacers821does not extend between a location upstream relative to the distributor818and a location downstream relative thereto, i.e., the spacers do not provide the bridging effect relative to the distributor.

As described above, in the prior art lances, the lower portions thereof tend to deflect downwardly at the distributor because the distributor is typically made of copper, in contrast to the tubes above and below the distributor, which are steel, and therefore generally stronger. Also, in the prior art, an o-ring gland is sometimes positioned substantially at the distributor, which also tends to cause the prior art lance to deflect at, or approximately at, the distributor. From the foregoing it can be seen, therefore, that the lance840provides a relatively stronger structure in which thermal expansion is accommodated and deflection of the body820is resisted by the internal support assembly842.

As can be seen inFIG. 9D, in one embodiment, a downstream portion848of the internal tube844preferably engages an upstream portion850of the lower inner tube834, to support the internal tube844in the predetermined position coaxial with the body820so that the internal tube844resists deflection of the body820. It is also preferred that an outer wall852of the internal tube844in the downstream portion848thereof engages an inner wall854of the lower inner tube834in the upstream portion850thereof, to support the internal tube844in the predetermined position coaxial with the body820so that the internal tube844resists deflection of the body820. As described above, the downstream portion848of the internal tube844and the upstream portion850of the lower inner tube826preferably are slidingly engaged with each other, so that the internal tube844thus supports the lower portion of the body generally, while simultaneously permitting movement of the internal tube844and/or the lower inner tube826relative to each other due to thermal expansion.

As can be seen inFIG. 9A, in one embodiment, the upper inner tube826preferably includes an upstream portion828proximal to the upstream end812, the upstream portion828being substantially cylindrical and having outer and inner diameters, a downstream portion830proximal to the distributor818, the downstream portion830having an outer diameter substantially larger than the outer diameter of the upstream portion and an inner diameter substantially larger than the inner diameter of the upstream portion, and a connecting portion832connecting the upstream and downstream portions828,830. As illustrated inFIG. 9A, the internal tube844has an outer diameter substantially smaller than the inner diameter of the downstream portion830, so that an annulus872is defined between the internal tube844and the downstream portion830. Preferably, the annulus872is in fluid communication with the ports819of the distributor818. It will be understood that the annulus872permits the second part of the gas to flow from the upstream portion828of the upper inner tube826to the ports819of the distributor818. It is preferred that each of the collars846includes one or more of the apertures874therein, to permit the second part of the gas to flow therethrough.

Another embodiment of a post-combustion lance940of the invention is illustrated inFIGS. 10A-10D. As can be seen inFIG. 10A, the lance940preferably includes a body920at least partially defined by an axis927thereof and extending between an upstream end912and a downstream end914of the lance940. The upstream end912is adapted to receive the gas directed into the lance under pressure, and the downstream end914includes a primary tip916through which a first part of the gas exits the lance940. The body920preferably includes upper and lower portions922,924and a post-combustion distributor918mounted therebetween at a predetermined distance “2Y” from the primary tip916. The upper and lower portions922,924are located upstream and downstream respectively relative to the distributor918. The distributor918preferably includes a plurality of ports919(FIG. 10D) through which a second part of the gas exits the lance. It is also preferred that the lance940includes a connecting tube955(FIGS. 10A,10C) for directing the gas to the upper portion922and a tip tube963(FIGS. 10A,10B) for directing the first part of the gas to the primary tip914. In one embodiment, the lance940preferably also includes an internal support assembly942for supporting the body920. Preferably, and as can be seen inFIG. 10A, the internal support assembly942includes an internal tube944extending between a downstream part948thereof positioned proximal to the downstream end914of the lance940, and an upstream part956of the internal tube944positioned upstream relative to the ports919of the distributor918(FIG. 10A). Preferably, the upstream part956is engageable with the connecting tube955(FIG. 10C) and the downstream part948is engageable with the tip tube963(FIG. 10B) downstream relative to the distributor918. It is also preferred that the lance940includes a lower o-ring gland971(FIG. 10B) positioned proximal to the lower portion924, to permit movement of the internal tube944and the tip tube963relative to each other due to thermal expansion, such movement being at least partially in an axial direction substantially parallel to the axis927. In one embodiment, the lance940preferably also includes an upper o-ring gland957(FIG. 10C) positioned proximal to the upper portion922, to permit movement of the internal tube944and the connecting tube955relative to each other at least partially in the axial direction due to thermal expansion.

As can be seen inFIGS. 10A-10D, the lance940preferably includes cavities through which water is directed, to cool the lance940. An inner cavity977is located between a lower intermediate element931, on one side thereof, and the internal tube944and the tip tube963, on the other side thereof. An outer cavity925is located between the lower intermediate element931and an exterior tube951(FIG. 10B). In one embodiment, it is preferred that water circulate through the cavities977,925to cool the lance. For instance, the water preferably flows through the inner cavity977in the direction indicated by arrow “2N1” inFIG. 10B, and the water also flows through the outer cavity925in the direction indicated by arrow “2O1” inFIG. 10B.

In one embodiment, the primary tip916preferably includes a nozzle959having one or more orifices960, and a tip tube963for directing the first part of the gas to the nozzle959. As can also be seen inFIG. 10B, the first part of the gas (e.g., oxygen) is directed through a central channel917defined by the tip tube963and the internal tube944and exits the lance940via the orifice960of the nozzle959. The direction of movement of the first part of the oxygen is indicated inFIG. 10Bby arrows “2M1” and “2M2”.

For the reasons described above, different elements of the lance are subjected to thermal expansion at different rates. As can be seen inFIG. 10B, the tip tube963preferably includes an engaged part969thereof which is slidably engaged with an engaged part973of the internal tube944. As indicated by arrows “2P1” and “2P2” inFIG. 10B, the engaged parts969,973are positioned for sliding engagement with each other, in the axial direction (i.e., substantially in the directions indicated by arrows “2P1” and “2P2” inFIG. 10B) due to thermal expansion of one or the other, or both, of the tip tube963and the internal tube944. In particular, an exterior surface964of the tip tube963and an interior surface967of the internal tube944preferably are positioned for sliding engagement with each other.

It is also preferred that the lower o-ring gland971is mounted on the exterior surface964of the tip tube963. It will be understood that the o-ring gland971preferably includes a suitable number of o-rings. For instance, in the embodiment illustrated inFIG. 10B, the lower o-ring971includes three o-rings, identified as968A-968C. Those skilled in the art will appreciate that the lower o-ring gland971accommodates the axial movement of the engaged parts969,973due to thermal expansion, and also provides a seal between the engaged parts969,973, to substantially prevent the water flowing through the inner cavity977from entering the central channel917.

The upper o-ring gland957is illustrated inFIG. 10C. The internal tube944is positioned coaxially with the axis927and with the connecting tube955. As can be seen in FIG.10C, the connecting tube955includes an engaged part979and the internal tube944includes an upper engaged part989, and the engaged parts979,989preferably are engageable with each other. In particular, it will be understood that the engaged parts979,989are slidingly engageable with each other, i.e., substantially in the axial direction. In particular, an interior surface995of the connecting tube955and an exterior surface996of the internal tube944preferably are positioned for sliding engagement with each other. As can be seen inFIG. 10C, the oxygen flows into the lance along a central channel983defined by the connector tube955and the internal tube944as indicated by arrow “2M3”.

The body of the lance940preferably also includes an upper intermediate element929. An inner cavity985is located between and defined by the upper intermediate element929, on one side thereof, and the connecting tube955and the internal tube944, on the other side thereof. Similarly, an outer cavity988is located between the upper intermediate element929and the exterior tube951. It will be understood that the inner cavity985of the upper portion is in fluid communication with the inner cavity977in the lower portion, and the outer cavity988of the upper portion is also in fluid communication with the outer cavity925in the lower portion. InFIG. 10C, the directions of flow of the water directed through the cavities, to cool the lance940, are indicated by arrows “2N2” and “2O2”.

As can also be seen inFIG. 10C, in one embodiment, the o-ring gland957preferably includes three o-rings, identified inFIG. 10Cas968D-968F. (It will be understood that the o-ring gland957may include any suitable number of o-rings.) The engaged parts979,989are movable relative to each other in the axial direction, as indicated by arrows “2P3” and “2P4” inFIG. 10C. For the reasons described above, one or both of the engaged parts979,989may move relative to the other, due to thermal expansion. As noted above, such movement preferably is in the form of sliding engagement of the engaged parts979,989with each other, i.e., one or both of the engaged parts979,989slidingly engaging the other, for movement relative to one or the other (or movement of both) substantially in the axial direction. The o-ring gland957permits such movement, and also provides a seal to substantially prevent water in the inner cavity977from leaking into the central channel983.

As illustrated inFIG. 10D, the second part of the gas exits the lance940via the ports919. The flow of the second part of the gas is schematically represented inFIG. 10Dby arrow “2M4”. As can also be seen inFIG. 10D, the first part of the gas flows past the distributor918via the internal tube944. The movement of the first part of the gas is schematically represented by arrow “2M5” inFIG. 10D.

The internal support assembly942preferably includes the internal tube944and one or more collars946located upstream relative to the distributor918. As can be seen inFIG. 10A-10C, the internal support assembly942preferably extends between an upstream end901(FIG. 10C) and a downstream end902(FIG. 10B), each of which is slidably engaged with a tube element respectively. For example, the upstream end901includes the engaged part989which, as described above, is engaged inside the engaged part979of the upper connecting tube955(FIG. 10C). As noted above, the engaged parts979,989are engaged with each other, but movable in the directions indicated by arrows2P3,2P4in order to accommodate thermal expansion of the connecting tube and/or the internal tube944. The connecting tube955accordingly supports the internal tube944at its upstream end901. Similarly, and as shown inFIG. 10B, the downstream end902of the internal tube944includes the engaged part973, which is slidably engaged with the engaged part969of the tip tube963. The tip tube963accordingly supports the internal tube944at its downstream end902.

In one embodiment, the internal support assembly942preferably includes one or more collars946secured to the internal tube944and engageable with the upper intermediate element929(FIG. 10D). Those skilled in the art will appreciate that the collar946is slidably engageable with the upper intermediate element929, to accommodate thermal expansion of, among other elements, the internal tube944and the upper intermediate element929.

From the foregoing, it can be seen that the body920includes substantially all of the lance940, excluding the internal support assembly942. For instance, the body920preferably includes the connecting tube955and the lower inner tube934, as well as the exterior tube951, the distributor918, the lower intermediate element931, the tip tube963, and the upper intermediate element929. It will be understood that, in one embodiment, the exterior tube951preferably is not a continuous physical element extending between upstream and downstream ends of the lance940, but instead is divided into two portions, i.e., one located upstream relative to the distributor918, and the other located downstream relative thereto.

From the foregoing, it can be seen that, in the lance940, the lower and upper o-ring glands971,957are positioned at the lower and upper ends of the lance, i.e., the o-ring glands971,957are positioned at predetermined distances2Q1,2Q2(FIG. 10A) apart from the distributor918. Also, and as can be seen inFIG. 10D, the lance940does not include an o-ring gland positioned at, or proximal to, the distributor918. The o-ring glands971,957are positioned generally proximal to the lower and upper ends of the lance respectively, and as shown inFIG. 10D, the lance940does not include an o-ring gland proximal to the distributor. As a result, the lance940is less prone to bending at the distributor918than the prior art lances, in which an o-ring gland typically is located proximal to the distributor.

In effect, the body920is supported above and below the distributor918by the internal support assembly942. The internal tube944is a single, unitary element extending between the upstream and downstream ends901,902of the internal support assembly942. Also, and as can be seen inFIGS. 10A and 10D, the internal tube944also is partly located proximal to the distributor918, so that the internal support assembly942supports the distributor918substantially directly.

The upstream end901and the downstream end902are located upstream and downstream respectively relative to the distributor918. Accordingly, the support provided by the internal support assembly942to the body920is a “bridging” effect, i.e., the internal support assembly942spans the distributor918between the upstream end901located upstream relative to the distributor918and the downstream end902, located downstream thereto. Also, and as can be seen inFIG. 10A, the o-ring glands971,957are positioned outside the internal support assembly942, i.e., outside the “bridging” portion of the lance940. As is known, the o-rings971,957are relatively weak. Because they are located at the ends of the internal support assembly942, they have virtually no effect on the structural strength of the lance940overall.

Those skilled in the art will also appreciate that, because of the sliding engagement of the internal tube944at its lower and upper ends, thermal expansion is accommodated.

In one embodiment, the post-combustion lance940preferably also includes one or more spacers921secured to the internal tube944and positioned between the upper intermediate element929and the internal tube, to support the internal tube in a predetermined position substantially coaxial with the upper portion922so that the internal tube944resists deflection of the body920. As described above, although the spacers provide only localized support to internal lance elements, the spacers help to align the elements of the lance properly as they are assembled. In particular, the spacers are not sufficiently extensive to provide the bridging effect provided by the internal support assembly942, as described above.

As can be seen inFIGS. 10A and 10D, the internal tube944additionally includes one or more openings986positioned at least partially upstream relative to the ports919of the distributor, to permit the second part of the gas to flow to the distributor.

An alternative embodiment of the post-combustion lance1040of the invention is illustrated inFIGS. 11A-11C. The post-combustion lance1040is for directing the gas at least partially therethrough, and includes a body1020at least partially defined by an axis1027thereof and extending between an upstream end1012and a downstream end1014of the lance1040. Preferably, the upstream end1012is adapted to receive the gas, and the downstream end includes a primary tip1016through which a first part of the gas exits the lance1040. It is also preferred that the body1020includes upper and lower portions1022,1024and a post-combustion distributor1018mounted therebetween at a predetermined distance “3Y” from the primary tip1016. The upper and lower portions1022,1024are located upstream and downstream respectively relative to the distributor1018. The distributor1018includes a number of ports1019(FIG. 11B) through which a second part of the gas exits the lance1040. In one embodiment, the distributor1018additionally includes a distributor tube1090extending upstream relative to the ports1019(FIG. 11B), and an upper inner tube1026positioned at least partially upstream from the distributor. The lance1040also includes an adaptor1091secured to the upper inner tube1026and engageable with the distributor tube1090, and a lower inner tube1034positioned at least partially downstream from the distributor (FIG. 11B). It is also preferred that the lance1040includes an internal support assembly1042for supporting the body1020. Preferably, the internal support assembly1042includes an internal tube1044positioned inside the body1020and engaged with the lower inner tube1034at least partially downstream relative to the distributor1018, and also engaged with the upper inner tube1026at least partially upstream relative to the distributor1018. As will be described, the lance1040preferably also includes a lower o-ring gland1071positioned proximal to the lower portion1024, to permit movement of the lower inner tube1034and the primary tip1016relative to each other due to thermal expansion at least partially in an axial direction substantially parallel to the axis. It is also preferred that the lance includes an upper o-ring gland1057positioned on the adaptor1091for engagement with the distributor tube1090, to permit movement of the upper inner tube1026and the distributor tube1090relative to each other due to thermal expansion at least partially in the axial direction. As illustrated inFIG. 11A, the upper inner tube1026is at least partially positioned in the upper portion1022, and the lower inner tube1034is at least partially positioned in the lower portion1024.

As can be seen inFIGS. 11A-11C, the lance1040preferably includes cavities through which water is directed, to cool the lance1040. An inner cavity1077is located between, on one side thereof, a lower intermediate element1031, and on the other side thereof, the lower inner tube1034and the tip tube1063. An outer cavity1025is located between the lower intermediate element1031and an exterior tube1051(FIG. 11C). In one embodiment, it is preferred that water circulates through the cavities1077,1025to cool the lance. For instance, the water preferably flows through the inner cavity1077in the direction indicated by arrow “3N1” inFIG. 11C, and the water also flows through the outer cavity1025in the direction indicated by arrow “3O1” inFIG. 11C.

Preferably, the primary tip1016includes a nozzle1059, and a tip tube1063for directing the first part of the gas to the nozzle1059. As can also be seen inFIG. 11C, the first part of the gas (e.g., oxygen) is directed through a central channel1017defined by the tip tube1063and the internal tube1044and exits the lance1040via an orifice1060of the nozzle1059. The direction of movement of the first part of the oxygen is indicated inFIG. 11Cby arrows “3M1” and “3M2”.

For the reasons described above, different elements of the lance are subjected to thermal expansion at different rates. As can be seen inFIG. 11C, the tip tube1063preferably includes an engaged part1069thereof which is slidably engaged with an engaged part1073of the lower inner tube1034. As indicated by arrows “3P1” and “3P2” inFIG. 11C, the engaged parts1069,1073are formed and positioned for sliding engagement with each other, in the axial direction (i.e., substantially in the directions indicated by arrows “3P1” and “3P2” inFIG. 11C) due to thermal expansion of one or the other, or both, of the tip tube1063and the lower inner tube1034. An exterior surface1064of the tip tube1063and an interior surface1067of the lower inner tube1034preferably are positioned for sliding engagement with each other.

It is also preferred that the lower o-ring gland1071is mounted on the exterior surface1064of the tip tube1063. It will be understood that the o-ring gland1071preferably includes a suitable number of o-rings. For instance, in the embodiment illustrated inFIG. 11C, the lower o-ring1071includes three o-rings, identified for convenience as1068A-1068C. Those skilled in the art will appreciate that the lower o-ring gland1071accommodates the axial movement of the engaged parts1069,1073due to thermal expansion, and also provides a seal between the engaged parts1069,1073, to substantially prevent the water flowing through the inner cavity1077from entering the central channel1017.

The upper o-ring gland1057is illustrated inFIG. 11B. The internal tube1044is positioned coaxially with the axis1027and with the upper inner tube1026. As can be seen inFIG. 11B, the upper inner tube1026includes an engaged part1079, and the internal tube1044includes an upper engaged part1089. The engaged parts1079,1089preferably are formed and positioned to be engageable with each other. In particular, it will be understood that the engaged parts1079,1089are slidingly engageable with each other, i.e., they are movable, while slidingly engaged with each other, substantially in the axial direction. As can be seen inFIG. 11B, the oxygen flows into the lance along a central channel1083defined by the upper inner tube1026and the internal tube1044as indicated by arrow “3M3”.

The body1020of the lance1040preferably also includes an upper intermediate element1029. An inner cavity1085is located between and substantially defined by the upper intermediate element1029, on one side thereof, and the upper inner tube1026and the distributor tube1090, on the other side thereof. Similarly, an outer cavity1088is located between the upper intermediate element1029and the exterior tube1051. It will be understood that the inner cavity1085of the upper portion is in fluid communication with the inner cavity1077in the lower portion, and the outer cavity1088of the upper portion is also in fluid communication with the outer cavity1025in the lower portion. InFIG. 11B, the directions of flow of the water directed through the cavities, to cool the lance1040, are indicated by arrows “3N2” and “3O2”.

As can also be seen inFIG. 11B, the adaptor1091preferably is secured to the upper inner tube1026at a location1092proximal to the adaptor's inner side1006. Also, the adaptor's inner side1006preferably is adapted for sliding engagement with the internal tube1044. The adaptor's outer side1093preferably is formed and positioned for sliding engagement with an interior surface1094of the distributor tube1090. It is also preferred that the upper o-ring gland1057is mounted on the outer side1093of the adaptor1091, so that the o-ring gland1057sealingly engages the interior surface1094of the distributor tube1090.

In one embodiment, the o-ring gland1057preferably includes two o-rings, identified inFIG. 11Bas1068D and1068E. (It will be understood that the o-ring gland1057may include any suitable number of o-rings.) The engaged parts1079,1089are movable relative to each other in the axial direction, as indicated by arrows “3P3” and “3P4” inFIG. 11B. However, it will also be understood that the distributor tube1090and the adaptor1091are also movable relative to each other (i.e., individually, or both of them simultaneously) due to thermal expansion. Movement of the adaptor1091and the distributor tube1090, or of each of them relative to the other, is substantially in the axial direction, i.e., in the directions indicated by arrows “3P3” and “3P4” inFIG. 11B.

For the reasons described above, one or both of the engaged parts1079,1089may move relative to the other, due to thermal expansion. As noted above, such movement preferably is in the form of sliding engagement of the engaged parts1079,1089with each other, i.e., one or both of the engaged parts1079,1089are movable due to thermal expansion. Also as described above, because the distributor tube1090and the adaptor1091are movable relative to each other substantially in the axial direction, such movement being due to thermal expansion, the interior surface1094of the distributor tube1090and the outer side1093of the adaptor1091slidingly engage each other when such movement takes place. The o-ring gland1057permits such movement, and also provides a seal to substantially prevent water in the inner cavity1077from leaking into the central channel1083.

As can be seen inFIGS. 11A and 11B, the internal tube1044extends between upstream and downstream ends1001,1002thereof that are respectively located upstream and downstream relative to the distributor1018. Proximal to the upstream end1001, the engaged part1089of the internal tube1044is slidably engaged with the engaged part1079of the upper inner tube1026, as described above. Also, along a length1004of the internal tube1044, the internal tube1044is slidably engaged with the lower inner tube1034. Accordingly, the internal tube1044is movable relative to the upper and lower inner tubes1026,1034(i.e., such relative movement taking place due to thermal expansion), in the directions indicated by arrows3P3and3P4inFIG. 11B. The adaptor's inner side1006preferably is also slidingly engaged with the internal tube1044.

From the foregoing, it can be seen that the body1020includes substantially all of the lance1040, excluding the internal support assembly1042. For instance, the body1020preferably includes the upper inner tube1026and the lower inner tube1034, as well as the exterior tube1051, the distributor1018, the lower intermediate element1031, the tip tube1063, and the upper intermediate element1029. It will be understood that, in one embodiment, the exterior tube1051preferably is not a continuous physical element extending between upstream and downstream ends of the lance1040, but instead is divided into two portions, i.e., one located upstream relative to the distributor1018, and the other located downstream relative thereto.

In effect, the body1020is supported above and below the distributor1018by the internal support assembly1042. Also, and as can be seen inFIGS. 11A and 11B, the internal tube1044also is partly located proximal to the distributor1018, so that the internal support assembly1042supports the distributor1018substantially directly.

The upstream end1001and the downstream end1002are located upstream and downstream respectively relative to the distributor1018. Accordingly, the support provided by the internal support assembly1042to the body1020is a “bridging” effect, i.e., the internal support assembly1042spans the distributor1018between the upstream end1001located upstream relative to the distributor1018and the downstream end1002, located downstream thereto. Also, and as can be seen inFIG. 11A, the o-ring gland1071is positioned outside the internal support assembly1042, i.e., outside the “bridging” portion of the lance1040.

As noted above, the o-ring gland1057preferably is positioned on the adaptor1091, i.e., the o-ring gland1057is located proximal to the distributor1018, i.e., the o-ring gland1057is located between the upstream and downstream ends1001,1002of the internal support assembly1042. However, it is believed that, due to the support provided by the internal support assembly1042between the upstream and downstream ends1001,1002thereof, the o-ring gland1057does not materially adversely affect the structural strength of the lance1040overall.

The lance1040preferably includes spacers1021(FIG. 11B). It will be understood that, although the spacers1021may provide support to the lance, any such support is localized (i.e., the extent of the support provided by the spacers is generally limited to the immediate vicinity thereof). In particular, it can be seen inFIGS. 11A and 11Bthat the support provided by the spacers1021does not extend between a location upstream relative to the distributor1018and a location downstream relative thereto, i.e., the spacers do not provide the bridging effect relative to the distributor.

As can be seen inFIG. 11A, the internal tube1044preferably includes one or more apertures1086for permitting the second part of the gas to flow to the ports1019of the distributor1018.

In one embodiment, the internal tube1044preferably is slidingly engaged with the lower inner tube1034. It is also preferred that the internal tube1044is slidingly engaged with the upper inner tube1026. Preferably, and as described, the adaptor1091is slidingly engaged with the distributor tube1090. Such sliding engagement is to accommodate relative movement of these components (i.e., relative to each other, respectively) due to thermal expansion.

Accordingly, the internal tube1044supports the body1020, creating a “bridging” effect in which the internal support assembly1042supports the body1020at locations that are both upstream and downstream relative to the distributor1018. Also, in the lance1040, the lower o-ring gland1071is positioned at the lower end of the lance, but the upper o-ring gland1071is positioned proximal to the distributor1018. However, the distributor tube, supported by the internal tube1044(via the adaptor1091) and the upper inner tube, resists deflection of the body1020in the vicinity of the distributor. As a result, the lance1040is less prone to bending at the distributor1018than the prior art lance.

It will be appreciated by those skilled in the art that the invention can take many forms, and that such forms are within the scope of the invention as described above. The foregoing descriptions are exemplary, and their scope should not be limited to the preferred versions provided therein.