GB2171186A - Improvements in apparatus for introducing substances into metal melts - Google Patents

Abstract

The injection apparatus (10) enables gas, gas plus powder, or gas plus wire to be fed via a plural-passage nozzle (18) through the wall of a ladle into a metal melt. An assembly consisting of a back plate (42) mounted on the ladle, a spacer block (51) and a mounting plate (50) supports a lance head (60) such that a feed pipe (25) extending therefrom projects down the nozzle (18) towards the melt. The lance head (60) comprises two bodies (62, 66) through which gas (etc.) is conducted to the pipe (25); by means of a ram (96) the head (60) and pipe (25) can be advanced from a retracted position to an operative, injection position and in the latter position the bodies (62, 66) of the lance head can be separated laterally, the outboard body (66) being replaced by a refractory closure (94) in a movable sector plate (90) pivoted to the mounting plate. The sector plate (90) is movable by a ram and when moved is responsible for separating the outboard body (66) from the companion body (62) when the bodies are separated, the supply of gas (etc.) to the pipe (25) is cut-off and any possibility of melt escaping via the pipe (25) is eradicated by the closure (94). <IMAGE>

Description

SPECIFICATION Improvements in apparatus for introducing substances into liquids, e.g. metal melts This invention relates to improvements in apparatus for introducing substances into liquids, e.g.

metal melts.

More particularly, the invention relates to apparatus to be installed in the wall of a vessel or conduit for the liquid for introducing substances deep into the liquid. Features of the invention include improvements in the manner in which a delivery pipe, tuyere or lance is mounted and in safeguarding against the outward leakage of the liquid therethrough. Apparatus according to the invention can possess one or more such delivery pipes. If more than one pipe is provided, various substances in different physical forms could be introduced to the liquid and hence the apparatus can be a very versatile aid to its user, the production chemist or metallurgist.

The present invention can be applied to the type of apparatus disclosed in our PCT patent application published under the number WO84/02147.

That apparatus was for treating liquids by injecting solid, gaseous or particulate substances into the liquid in a vessel of some kind or while flowing along a conduit or channel.

Liquids to be treated will ordinarily be at such high temperatures that they may be regarded as aggressive or dangerous. The apparatus we have developed has been designed to be safe in operation as well as adequately protected from the liquid up to the time treatment is to begin. The present improvements aim to enhance aspects of safety and/or convenience of use of the apparatus.

Exemplary liquids for treatment include molten slags and metals. Both ferrous and non-ferrous melts may be treated for diverse purposes using the apparatus.

The apparatus could also be used in winning or refining selected metals from their ores. For example, tungsten can be won by reduction in an arc furnace of the ore or an oxide thereof to the molten metallic state. The present apparatus can be employed to blow fresh powdered ore or oxide into the metallic melt of the furnace.

Our apparatus can be employed when making steel from iron. It is suitable for use in vacuum degassing as a convenient means to introduce alloying additions. Primary and secondary refining, deoxidizing and desulphurizing can be performed to advantage with the aid of the apparatus. Compositions of steels (and other metals) can be controlled or modified by introducing gaseous, solid or powdered substances at any time before solidification. For instance, the melt can be treated in the furnace, in the ingot mould, as well as in vessels such as steel making vessels, ladles of various kinds, degassers and tundishes.

Before or during teeming in a metal casting operation, it may be necessary or desirable to introduce gas into the molten metal in a container or vessel. Gas is injected, e.g. into the bottom area of a vessel, for diverse purposes. These include rinsing; clearing the relatively cool bottom area of solidification products, to help remove them from the vicinity of a vessel bottom outlet from which the metal may be teemed; equalising the temperature throughout the melt; and stirring to help disperse alloying additions uniformly in the melt. Usually an inert gas such as argon is used. Reactive gases such as oxygen, carbon dioxide and hydrocarbon gases are sometimes substituted, depending on the melt chemistry.

Previous gas injection proposals have envisaged porous bricks in the refactory lining of a vessel, solid porous plugs in sliding gate teeming valves, and conventional consumable lances. Published patent specification WO84/02147 discusses the various merits and demerits of these prior approaches.

The apparatus disclosed in published patent specification No. We84!02147 is capable of introducing substances deep into a metal melt and provides benefits not so readily attainable by the consumable lances conventionally employed. By means of this apparatus, precise dosing of the melt is a very straightforward operation. In its preferred form, inert or reactive gases can be blown into the melt in the course of introducing powders or solids.

In ferrous metallurgy, the melt must often be deoxidised and desulphurised by introducing aluminium and calcium or its alloys. Composition control or "trimming" is commonly performed by dissolving solid or powdered alloying additions in the melt. Many materials can be added to melts to overcome the deleterious effects of impurities or to tailor the melts to produce specified compositions.

We do not propose to provide an exhaustive catalogue of possible treatment materials. The choice of materials will depend on the melts, their starting and finishing compositions; it is well within the purview of the works chemist or metallurgist to choose appropriate addition(s) as each situation demands. Introducing additions to a steel melt - or indeed any other metal melt -can be troublesome especially if the alloying addition is readily melted, oxidised or vaporised. Thus, adding aluminium to a steel melt can be a difficult operation in view of the low melting point of aluminium. No significant deoxidation would be achieved if the aluminium were simply dumped onto the melt: it has to be delivered deep into the melt so it has time to li- quify and react rather than float ineffectively on top of the melt. Calcium moieties have to be fed deep into the melt.Previous delivery methods include use of a lance or sophisticated and expensive equipment for firing the alloying addition deep into the melt. Lancing is apparently simple but has drawbacks; our apparatus has been found to be extremely convenient to use and to offer high efficiency in terms of the amount of additive, e.g. Al.

actually taken up by the melt, compared with losses of the additive to the slag or by unproductive vaporisation.

According to the present invention there is provided apparatus for introducing one or more treat ment substances through the wall of a containment vessel into an elevated temperature liquid therein comprising a feed pipe for one or more of said substances and a head or inlet member attached to an outboard end of the feed pipe, the inlet member having at least one port for connection to a supply of a treatment substance and at least one passage therefrom for conveying the supplied substance(s) into the pipe, the inlet member comprising first and second bodies together defining the passage(s) and held united at a plane interface therebetween with the aid of fastening means shearable at said interface, the second body, which is the body further from the pipe, being displaceable laterally relative to the first body to which the pipe is attached upon fracture of the fastening means, for rapidly terminating feeding of the substance(s) along the feed pipe, and closure means being provided for the passage in the first body the said means being movable to a passage-closing position as the second body is displaced laterally.

Also according to the present invention there is provided apparatus for introducing one or more treatment substances through the wall of a containment vessel into an elevated temperature liquid therein, comprising a feed pipe for one or more of said substances and a head or inlet member attached to an outboard end of the feed pipe, the inlet member having at least one port for connection to a supply of a treatment substance and at least one passage therefrom for conveying the supplied substance(s) into the pipe, the inlet member comprising an inboard and an outboard body together defining the passage(s) and held united at a plane interface therebetween by fastening means which are shearable at said interface, the apparatus further comprising means to support the inlet member for movement from a retracted pre-injection position to an advanced injection position and injection-terminating means mounted on the support means and operable, when the inlet member is in its advanced position, firstly to displace the outboard body laterally relative to the inboard body, with accompanying shearing of said fastening means and secondly to dispose a closure means in a position across the interface in contact with the inboard body thereby closing the passage(s) therein.

The invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 is a longitudinal sectional view of injection apparatus according to the invention, with a mechanism part of said apparatus in a "stand-by" condition, Figure 2 is a fragmentary sectional view of the mechanism part of the injection apparatus, said mechanism being in an "active" condition, Figure 3 is an end view of the apparatus, showing lines I-I and ll-ll corresponding to the planes of Figures 1 and 2 respectively, Figures 4 and 5 are longitudinal sectional views, taken on lines A and B respectively appearing in Figure 6, of a separable lance head according to an aspect of this invention, Figure 6 is an end view of the separable lance head of Figures 4 and 5, Figure 7 is an end view, similar to Figure 6, of a second separable lance head according to this invention, Figure 8 is a longitudinal view of the second lance head, Figure 9 is a longitudinal sectional view of a lance pipe according to the invention, Figure 10 is a longitudinal sectional view of a third lance head according to this invention, Figure 11 is an end view of the third lance head, and Figure 12 is a transverse cross-sectional view taken on the line Ill-Ill of Figure 11.

Figure 1 shows injection apparatus 10 for injecting substances into a molten metal 12 contained inside a vessel such as a ladle 14. Using the apparatus 10, substances can be injected into the melt at a location deep below the melt surface to optimise the effects of the substances on the melt, such as their reactions therewith. Gases can be injected for rinsing, mixing or temperature-equalising purposes. Gases can also be injected for reacting with the melt. Melt-treatment substances, e.g. alloying additions, in the form of wires or rods can be injected too, in streams of protective gas. Powdered treatment or alloying substances can also be injected using the apparatus 10. The powdered substances are injected borne upon a suitable carrier gas.

In Figure 1 the apparatus 10 is shown attached to the outer wall 16 of the ladle 14, for delivering the required substances via a nozzle member 18 extending through the ladle outer and inner wall.

The nozzle member is cemented into a receiving opening provided either in the insulating lining 19 forming said inner wall or in a well block (not shown) mounted in said lining.

The nozzle member 18 is a pressed and fired refractory or, preferably, a cast refractory concrete.

At least one passage traverses the nozzle member 18 from its outer to its inner end, to permit a treatment substance to be fed through the nozzle member for ejection into the melt. The number of passages 20 is immaterial. There can be two or, as in this embodiment, four passages 20 equispaced about the longitudinal axis of the nozzle member.

The discharge end of each passage is closed by refractory plugging means against entry of melt.

The plugging means 21 can be dislodged from the passage (into the melt) when the user is ready to commence an injection exercise via the passage.

Optionally, each passage is lined by a metal sleeve 22 extending along most of its length save for a portion of the passage adjacent the discharge end.

Slidably movable in each passage 20 is a lance pipe 24 or 25. As'will become apparent as this description proceeds, at any one time the illustrated apparatus 10 has two operational passages 20 and two non-operational passages 20. When setting up the apparatus 10, the two chosen non-operational channels 20 have "dummy" lance pipes 24 in stalled therein as a safety measure. Should the plugging means 21 become dislodged or allow melt to leak past them (a very unlikely event) melt will enter and freeze to the dummy pipes 24, effectively closing these pipes against any risky escape of melt via the apparatus. The non-operational passages and their dummy lance pipes 24 are shown in Figure 1. The operational passages and associated lance pipes 25 are shown in Figure 2.

The lance pipes 25 can have a construction as shown in Figure 9. Pipe 25 has an outer steel tube 28 screw-threaded externally at one end 29. Internally, the steel tube is lined by a refractory tube 30, e.g. fused mullite. A refractory cement fills a space between the tubes 28 and 30. The refractory inner tube 30 extends beyond the steel tube 28 at the discharge end of the pipe 25. The projecting portion of tube 30 is encased in a high duty cement sheath 32 e.g. a phosphate-bonded alumina/ chrome cement.

For fitting the apparatus 10 to the ladle 14, a suitably shaped adaptor plate 34 is welded to the outer wall 16 around the opening therein through which the nozzle member 18 is inserted. A locating ring 36 for the apparatus and the nozzle member is bolted to the adaptor plate. The locating ring 36 has radially inner and outer circumferential recesses 37, 38 providing seatings which serve to position the nozzle member 18, the ring 36 and a back plate 40 coaxially relative to one another. A peripheral flange 39 of the nozzle member 18 fits in the inner recess 37. A circumferential lip 42 extending from one face of the back plate snugly and rotationally encircles the recess 38. Screws, e.g. 44, pass through slots in the back plate 40 and are used to clamp the plate in an appropriately adjusted rotational position to the locating ring 36.

When properly clamped, apertures 45 in the back plate 40 register with the passages 20 in the nozzle member 18.

A centrally-mounted stud 46 projects from the back plate 40 in a direction away from the ladle 14.

Screw threaded to the stud 46 is a clamp nut 47 used for securing a mounting plate 50 and spacer block 51 to the back plate. The stud 46 of course passes through a central opening in both the plate 50 and block 51. Also fastened to the back plate 40 is a locating peg 52.

Both the mounting plate 50 and spacer block 51 have apertures disposed for selective registry with the apertures 45 in the back plate 40 and the nozzle passages 20. The mounting plate 50 has two apertures 53, diametrically-opposed, which are to be registered with the currently operational passages 20. The spacer block 51 has two pairs of apertures, however. One diametrically-opposed pair of its apertures 54, 54' is initially vacant and these apertures are for alignment with the operational passages. The other diametrically-opposed pair of apertures 56, 56' are for alignment with the currently non-operational passages 20. Apertures 56, 56' are closed by refractory closures 58 cast in situ or otherwise anchored therein. Closure 58 guard against the damaging effects of any leakage of melt along the non-operational passages 20.Such a leakage is highly unlikely, but just conceivable if the user omitted to insert the dummy pipes 24.

Both the mounting plate 50 and the spacer block 51 further possess two openings 52' appropriately positioned to coact with the locating peg 52 projecting from the back plate 40. By means of the peg 52 and apertures 52', the block 51 is orientated with its closures 58 in conjunction with the dummy pipes 24 and non-operational nozzle passages, while its vacant apertures 54, 54' are aligned with the operational passages. Likewise, the mounting plate 50 is orientated with its apertures 53 coincident with said passages and the apertures 54, 54'.

After an injection operation using the two currently operational passages, the apparatus can be readied for using the two previously non-operational passages. For this, the mounting plate 50 and spacer block 51 have to be rotated 90" about the stud 46 to their new operating situation, and of course the dummy pipes 24 will be extracted and replaced by fresh lance pipes 25. This entails removing the clamp nut 47 and then the plate 50 and block 51. Access is thus afforded to the dummy pipes 24, and after they have been removed the plate 50 and block 51 are relocated in their new operating situation. The peg 52 is then in its alternative openings 52' in the plate 50 and block 51.

The two apertures 53 in the mounting plate 50 align with the two apertures 54, 54' in the spacer block 51; all these apertures are of equal diameter.

The diameter is such that the aligned apertures will accommodate lance heads 60 which are mounted on the screw-threaded ends 29 of the operational lance pipes 25. The lance heads 60 are shown in detail in Figures 4 to 8. Two versions are illustrated.

From Figures 4, 5 and 6, it will be appreciated that the lance head 60 comprises a pair of cylindrical bodies 62, 66. The larger body 62 is internally screw-threaded at 63 for the lance pipe 25 to be secured thereto. A central passageway 64 extends axially through body 62 and also through the smaller body 66 which is held to the larger body by two screws 68. The bodies 62, 66 also have a second passageway 69 which interconnects with passageway 64 inside the larger body 62. In the vicinity of the contacting faces of the bodies, the passageway 64 is enlarged and in the enlarged portion there is a constriction or guide formed by components 70, as, 72. The components 71, 72 are hardened steel bushes. Component 70 is a PTFE seal which fits snugly on the wire, to prevent gas escaping rearwardly along the wire feed conduit 75. Smaller body 66 has screw-threaded ports 73, 74 to the passageways 64 and 69 for respective conduits 75, 76 to be coupled to said passageways.

This lance head 60 is for the injection of a treatment substance in the form of a wire or rod, accompanied by a suitable gas e.g. argon. The wire enters the lance pipe 25 via passageway 64 from the conduit 75 which leads to a wire feeder, not shown. The constriction 72 guides the wire for smooth passage into the pipe 25. The gas from a source, not shown, enters passageway 69, and ultimately passageway 64, from the conduit 76.

The screws 68 enter appropriate fasteners 78 anchored in the larger body 62. At the points where they pass the contacting faces of the bodies 62, 66, the screws 68 are necked, i.e. at 79. Being for preference brass, the screws can be sheared at their necks to allow the smaller body 66 to be separated in a sideways direction from the larger body 62.

Such a separation is performed when injection of wire is completed. The accompanying movement of hardened bush 71 sideways relative to companion bush 72 will shear through the wire.

The lance head 60' shown in Figures 7 and 8 is generally similar to the foregoing. This head, however, is for a lance pipe meant for injecting gas only, or gas plus a powdered treatment substance.

Therefore, head 60' has but one passageway 64, which this time does not have a central enlarged portion. Inside the larger body 62, the passageway has an enlarged, downstream portion 80. A venturi-type nozzle insert 82 is located in the downstream portion 80. The two bodies 62, 66 are secured together by three shear screws 68 in this instance.

Before an injection operation is performed using either lance pipe 25, the downstream ends of the lance pipes are spaced from the passage plugging means 21. The pipes then extend through the apertures 45 in back plate 44 (see Figure 2) and across the apertures 54, 54' in the spacer block 51. They then enter the larger bodies 62 of the lance heads 60. The downstream ends of the heads 60 reside slidably in the apertures 53 in the mounting plate 50. The lance heads 60, 60' project outwardly from the openings 53 through similar openings 88 in respective pivotally-mounted sector plates 90, 92.

The two sector plates can pivot or swing in contact with the mounting plate 50, on bolts 93 passing through the mounting plate. In addition to the two openings 88, the sector plates each possess a closure disc 94 mounted in an aperture 95 adjacent its opening 88. Each closure disc 94 is positioned for alignability with a related aperture 53 of the mounting plate upon termination of an injection operation. The closure discs 94 are a safety feature and protect the apparatus if, on termination of injection, any melt spurts back along the respective lance pipes. The discs can be made of refractory material, e.g. cast in situ in their apertures 95. Alternatively, they could be metal e.g. copper. Desirably, the discs are readily replaceable.

Also provided are two pairs of actuators, conveniently hydraulic rams, and a pair of safety stops.

Each pair of rams is associated with a respective sector plate, and comprises a first ram 96 acting through a suitable linkage 97 upon the associated lance head 60, 60' projecting through the sector plate and a second ram 98 acting on the latter for pivoting it on its pivot bolt 93. The first rams 96 are fixedly mounted on the related sector plates 90, 92. The second rams 98 are fixed to the mounting plate 50 and engage thrust pins 99 on the sector plates.

The safety stops 100 are pivoted to the mounting plate. In their normal or initial settings, the stops coact with the linkages 97 to prevent the first rams 96 from thrusting the lance pipes 25 against the passage closing means 21. Pressure in rams 96 and said stops 100 locate and retain the lance pipes 25 in initial, ready positions, The safety stops are moved from their initial settings, when an injection operation is to commence, e.g. by means of a crowbar. Having shifted a safety stop 100, the associated first ram 96 is free to thrust the lance pipe at the passage closing means 21, dislodging the latter for injection to proceed. Movement of the lance pipe 25 stops when the downstream end of lance head 60 bottoms against the back plate 40.

Pressure in the ram 96 holds the lance head in this position.

The axial length of the larger body 62 of each lance head equals the combined axial thickness of the spacer block 51 and the mounting plate 50.

Therefore, the interface between the lance head bodies 62, 66 is coincident with the outer face of the mounting plate 50. Upon termination of an injection operation, the sector plate 90 or 92 can be caused by second ram 98 to swing about its pivot bolt 93 to shear the smaller body 66 from the larger body 62. The closure disc 94 is then brought into registry with opening 53 of the mounting plate 50. In this position, the closure disc 94 closes the passage through the lance head 60 and the sector plate traps the larger head body 62 against movement from its activated position.

Use and operation should be apparent from the foregoing description, but will be summarised below.

At the outset, one diametrically-opposed pair of passages 20 are chosen for injection and the other pair as reserves. With the mounting plate 50 and spacer block 51 detached from the back plate 40, dummy lance pipes 24 are installed in the chosen reserve passages. Either now, or after attaching the mounting plate 50 and spacer block 51 to the back plate 40, the injection pipes 25 are installed. These pipes have their lance heads 60, 60' attached thereto. The type of head employed will depend on whether or not wire is to be introduced to the melt The lance pipes 25 are kept spaced from the passage closing means 21 by the safety stops, which are in their initial settings. The necessary connections to the lance heads 60, 60' and to the rams 96, 98 are made. Thereafter the ladle is filled with melt.

Gas is pumped through the lance pipes before injection commences. The gas leaves the pipes 25 at their open downstream ends and cannot enter the melt owing to the passage closing means 21.

The gas flows back between the pipes 25 and their passages or liners 22, and exhausts to atmosphere via outlet slots or openings 51a in the front of the spacer block 51. These openings are later automatically closed to gas escape, when the lance pipes and their heads 60 are advanced to their operative injection positions.

At a convenient time, injection along one of the lance pipes 25 is initiated as follows. The associated safety stop 100 is displaced from its normal setting, allowing ram 96 to thrust the lance pipe 25 forward at the closing means 21, dislodging the latter. Once the necessary injection of gas, gas and powder or gas and wire has been performed, second ram 98 is activated to pivot the sector plate 90 or 92 on its pivot bolt 93. The smaller lance head body 66 is sheared from the larger 62 and with it the wire (if wire was being injected) is sheared.

The closure disc 94 is disposed across the upstream end of the larger lance head body 62 and injection is immediately cut off. As gas pressure falls in the lance pipe 25, melt may run into it and should then freeze, typically about 2 inches (5 cm) from the melt end of the lance pipe. In the most unlikely event of molten metal running back further, it will be prevented from escaping from the injection apparatus by the closure 94 in the sector plate.

Having injected along one lance pipe, injection can be commenced along the other lance pipe 25.

This lance pipe could be used for treating another batch of melt. Alternatively, both pipes 25 could be used to introduce different treatment substances into the same melt. Both pipes could be actively injecting at the same time.

When the lance pipes 25 have been used, and the ladle has been emptied, the apparatus 10 is prepared for injection using the reserve passages.

Following disassembly of plate 50 and spacer block 51, the used lances 25 are left in situ, and their head bodies 62 are unscrewed therefrom. The previous dummy lance pipes 24 are removed from their passages and new lance pipes 25 are installed. The apparatus 10 is then reassembled, i.e.

the spacer block 51 and mounting plate 50 are secured back in place to the back plate 40. It will be appreciated that the spacer block is now so re-oriented that its closures 58 are aligned with the previously-used passages 20 while its apertures 54, 54' align with the passages 20 to be used. The mounting plate 50 is appropriately re-oriented to suit as will be apparent.

With the present embodiment, when all four passages 20 have been used for injection, the nozzle member 18 will either be replaced or possibly reused if its condition is adjudged satisfactory. For re-use, new passage closing means 21 will be installed and possibly new liners 22 will be fitted. For removing the nozzle member 18, it is necesssary to detach the apparatus 10 from the ladle by releasing the screws 44 holding the back plate 40 to the locating ring 36. For removing the nozzle member 18 from its seating, the member 18 has a draw bolt 101 anchored centrally in its body; a suitable puller is attached to the draw bolt.

Upon installation of a nozzle member, there is no need to be precise as to its orientation rotationally about its central axis. The back plate 40 has arcuate slots for the attachment screws 44 so that the back plate can be rotated (on locating ring 36) to bring its apertures 45 into coincidence with the passages 20. Having set the back plate properly in position, it will appropriately align the spacer block 51 and mounting plate 50 (in either of their two functional positions) thanks to the locating peg 52 and the openings 52' therefor.

The injection apparatus could be simplified if desired, e.g. so as to have only one or two injection channels. The spacer block 51 could then be made integral with the mounting plate 50 and would not incorporate the closures 58.

If space permits, then by suitable modification of the mounting plate, a four-channel injection device could be arranged so there is no need to reposition the mounting plate and its allied components after injecting along two of the channels. The mounting plate 50 would then have four sector plates and safety stops, and the spacer block could be made integral with plate 50, the closures 58 being omitted. Dummy injection pipes might be dispensed with. In such a modification, there could be two or four pairs of rams as described above. If but two pairs of rams were employed, they would be dismountably secured to the mounting and sector plates. Then, after injections through two of the injection channels, the rams would be repositioned for injection along the other two channels.

There is no absolute need for the apparatus to be furnished with hydraulic actuators, although they are a great convenience. Hand-operated levers and suitable linkages could be used instead, with appropriate safety locks to prevent improper operation of the apparatus.

As disclosed hereinbefore, termination of injection is accomplished by severing the connection between the two bodies of the lance heads 60, 60' and the displaceable outer body 66 was replaced by a separate closure - an injection terminating means - which was biassed into contact with the other body. The closure was the pivoted sector plate 90, 92. The sector plate was forcibly pivoted against the displaceable body 66 to thrust the latter sideways from the companion body 62 (to which the feed pipe was secured), in the process shearing two or three fasteners which hitherto had held the two bodies together. As the displaceable body was dislodged sideways, the sector plate occupied its previous position and thereupon closed the feed passage comprising the feed pipe and the inlet member body still attached thereto.The second plate is a safety feature which ensures that high temperature liquid cannot escape from the vessel or ladle via the feed pipe on terminating a feeding operation.

In a modification now to be described with reference to Figures 10 to 12, the displaceable body is held captive to the other body by a spring-biassed pivot, and is secured in an operative or feeding position by a single shearable fastener. The displaceable body is moved through a small arc when a feeding operation is terminated, and a portion of the displaceable body itself now serves as a closure. Thus, a separate closure element is no longer required.

The displaceable body can be adapted to allow some gas to flow into the companion body and the pipe attached thereto, when the former body is pivoted to its feed terminating position. It is believed that this gas flow will help to ensure that flow-back of the high temperature liquid, e.y. molten steel, in the feed tube is kept within safe limits.

The lance device 110 illustrated in the accompa nying drawings is for use in or with the apparatus as disclosed in Figures 1 to 3 for introducing a substance, e.g. a gas or gas plus powder into the liquid. It could be used however, to introduce wire when it will ordinarily include shear bushes and a suitable gas passage, as in the lance head 60 described above.

The lance device 110 has a feedpipe or lance pipe 125 which can have the same form as the lance pipe 25 described earlier. At one end 129, the lance pipe 125 is screw-threaded for attachment to a lance head 160. Two bodies 162, 166, suitably fastened together comprise the lance head. The larger body 162 is internally screw-threaded at 163 for the lance pipe 125, and the smaller body 166 has a screw-threaded port 173 for attachment of a supply conduit 175 for a substance to be injected.

Each body 162, 166 has a passage for the substance to pass from the conduit 175 to the feed pipe 125 in the normal operating positions of the two bodies as illustrated. The passages are then aligned providing a throughflow passageway 164.

The body 166 is secured to body 162 in the normal operating position by a pivot bolt means 200 and by a readily shearable screw 168. The screw 168 passes through a clearance hole in the body 166 and enters a suitably threaded bore in companion body 162. The screw 168 can be made of brass, and is necked at a position corresponding to the interface between the bodies 162, 166 to enable it to be sheared at this location.

The pivot bolt means 200 comprises a bolt 200' which extends freely through aligned bores 201, 202 in the bodies 162, 166. The head 204 of the bolt engages an outer surface of the body 166 through an intervening washer. The stem 206 of the bolt 200' enters an enlarged counterbore 210 in the body 162. The end of the stem 206 has an internally-threaded bore for a machine screw 212.

The screw 212 secures a spring-retaining plate 214 to the stem. The said plate 214 captivates a spring 216 in the counterbore. The spring 216 is in compression and serves, through the bolt 200' to bias body 166 firmly against body 162. The biasing is such that gas flowing through the bodies to the lance pipe 125 cannot escape at all, or to any significant extent, via the aforesaid interface between the bodies. If desired, a seal ring could be sandwiched between the two bodies.

The pivot bolt means 200 keeps the bodies 162, 166 united even though screw 168 is sheared upon terminating the feeding of a substance.

The body 166 has a circular recess 220 in its face 222 which contacts the body 162. The recess 220 is beside the passage in this body. The recess and passage are centred equidistantly from the pivot axis of the pivot bolt means 200. A disc e.g. a refractory pellet 224 is suitably secured in the recess 220. The pellet 224 is pierced by a small bore 226.

A gas-supply passageway 228 leads through the body from its main passage to the bottom of the recess 220, the passageway being aligned with the bore 226. Item 230 is a sealing plug provided to close a bore machined necessarily in the body in the course of forming the passageway 228. Instead of a refractory pellet, disc 224 could be metallic, e.g. copper.

In use, the device 110 is in the condition shown in Figure 10 before and during supply of gaseous substance to the liquid e.g. steel. When the supply of the substance is to be terminated, an actuator not shown - is operated to displace the body 166 relative to body 162. The displacement is paraliel to the interface, the body 166 moving about the pivot bolt means 200. As the body 166 is forcibly moved from its Figure 10 position, the necked screw 168 is sheared at the interface. In operation, the actuator displaces the body 166 to bring the refractory pellet 224 into registry with the main passage in the body 162.

Gas is fed to the liquid at pressure. The operating conditions are such that termination of he gas feed by displacement of the body 166 so suddenly reduces the pressure in the lance pipe 125 that liquid e.g. steel may be sucked into it a significant distance along the pipe. This could be dangerous or damaging to the associated apparatus. To avoid this problem, and as a beneficial safety measure, the closure 224 is enabled to pass a limited amount of gas supplied via conduit 175 into the lance pipe. The gas enters the latter via passageway 228 and bore 226. Gas entering the pipe 125 from the closure can maintain enough pressure in the pipe 125 to confine flow-back of the liquid safely to the downstream end portion of the pipe.

The liquid may then freeze safely in this portion of the lance pipe.

As an alternative to the passageway 228 and bore 226, gas could flow into the pipe 125 from the conduit 175 when the body 166 is displaced from its initial injection position, if a groove is provided at the interface between the bodies. The groove may be in the larger body 162, in which case it opens to the passage 164 therein and extends to a position communicating with the passage 164 in the smaller body 162 after the latter has been displaced. Alternatively, a groove may be formed in the face 222 of the smaller body 162. The groove will then extend from the centre of the closure 220 to the passage 164.

For using the device 110 with the apparatus disclosed in Figures 1 to 3, only quite modest modification of the mechanical arrangements will be necessary. It is believed that the modifications needed will be readily perceivable by the ordinarily skilled addressee. The main modification is to dispense with the sector plate (90, 92) and to adapt the hydraulic ram previously employed to move the sector plate so as to be drivingly engageable with the body 166. Safety interlocks and mechanical stops can be provided inter alia (a) to ensure that the lance pipe 125 cannot be removed inadvertently from the appparatus (b) to confine the body 166 to movement from its normal position to its proper feed termination position and (c) to prevent the body 166 subsequently being moved out of the latter position.

The embodiment of Figures 4 to 8 can be adapted as described in connection with Figures 10 to 12 to pass a limited flow of gas into the lance pipe when injection is terminated.

Claims (23)

1. Apparatus for introducing one or more treatment substances through the wall of a containment vessel into an elevated temperature liquid therein, comprising a feed pipe for one or more of said substances and a head or inlet member attached to an outboard end of the feed pipe, the inlet member having at least one port for connection to a supply of a treatment substance and at least one passage therefrom for conveying the supplied substance(s) into the pipe, the inlet member comprising first and second bodies together defining the passage(s) and held united at a plane interface therebetween with the aid of fastening means shearable at said interface, the second body, which is the body further from the pipe, being displaceable laterally relative to the first body to which the pipe is attached upon fracture of the fastening means, for rapidly terminating feeding of the substance(s) along the feed pipe, and closure means being provided for the passage in the first body, the said means being movable to a passage-closing position as the second body is displaced laterally.

2. Apparatus according to claim 1, wherein the feed pipe is an expendable item removably attached to the inlet member.

3. Apparatus according to claim 2, wherein the feed pipe comprises a metal tube in which is cemented an inner refractory sleeve extending from its outboard end along a major part of its length.

4. Apparatus according to claim 1, 2 or 3, wherein the first and second bodies are held united solely by a plurality of shearable screw fasteners, and the closure means is adapted to displace the second body laterally and to occupy the position previously occupied by the second body when the closure means assumes its passage-closing position.

5. Apparatus according to claim 1, 2 or 3, wherein the first and second bodies are held united by a pivot bolt and at least one shearable screw fastener, and the second body when displaced laterally by a swinging movement about said pivot bolt serves as said closure means, the second body having a passage closing element located alongside the passage therein which element assumes the passage-closing position upon displacement of the second body.

6. Apparatus for introducing one or more treatment substances through the wall of a containment vessel into an elevated temperature liquid therein, comprising a feed pipe for one or more of said substances and a head or inlet member attached to an outboard end of the feed pipe, the in let member having at least one port for connection to a supply of a treatment substance and at least one passage therefrom for conveying the supplied substance(s) into the pipe, the inlet member comprising an inboard and an outboard body together defining the passage(s) and held united at a plane interface therebetween by fastening means which are shearable at said interface, the apparatus further comprising means to support the inlet member for movement from a retracted pre-injection position to an advanced injection position and injection-terminating means mounted on the support means and operable, when the inlet member is in its advanced position, firstly to displace the outboard body laterally relative to the inboard body, with accompanying shearing of said fastening means and secondly to dispose a closure means in a position across the interface in contact with the inboard body thereby closing the passage(s) therein.

7. Apparatus according to claim 6, wherein the feed pipe is an expendable item removably attached to the inlet member.

8. Apparatus according to claim 7, wherein the feed pipe comprises a metal tube in which is cemented an inner refractory sleeve extending from its outboard end along a major part of its length.

9. Apparatus according to claim 6, 7 or 8, wherein the first and second bodies are held united solely by a plurality of shearable screw fasteners, and the means operable to displace the second body laterally occupies the position previously occupied by the second body and serves then as the said closure means.

10. Apparatus according to claim 6, 7 or 8, wherein the first and second bodies are held united by a pivot bolt and at least one shearable screw fastener, and the second body when displaced laterally by a swinging movement about said pivot bolt serves as said closure means, the second body having a passage closing element located alongside the passage therein which element assumes the passage-closing position upon displacement of the second body.

11. Apparatus according to any of claims 6 to 8, wherein the support means has an opening to accommodate the inlet member when advanced into its advanced position, a first surface for abutment by the pipe end of the inboard body when the latter is advanced, and an outboard second surface spaced from the first surface so as to be coplanar with the said interface when the inlet member is advanced, injection-terminating means incorporating said closure means being slidably movable across the second surface.

12. Apparatus according to claim 11, wherein the injection terminating means is pivoted to the support means for swinging movement in contact with said second surface.

13. Apparatus according to any of claims 6 to 8, 11 or 12, wherein the injection terminating means is a movable plate having an opening which accommodates the inlet member for movability in an initial position of the plate, a refractory insert being mounted in the plate alongside the opening for contact with the inboard body when the plate is moved firstly to displace the outboard body and second to close the passage(s) in the inboard body.

14. Apparatus according to any of claims 6 to 13, further including two independently-operable actuators, one for advancing the inlet member and the attached pipe to the injection position and the other for displacing the outboard body when terminating injection.

15. Apparatus according to claim 14 when dependent on claim 11, 12 or 13, wherein both actuators are hydraulic rams, the said one actuator being mounted on the injection-terminating means and being in a force-transmitting relationship with the inlet member at its outboard end, and the other actuator being mounted on the support means in force-transmitting relationship with the injection terminating means.

16. Apparatus according to any of claims 6 to 15, further including a displaceable stop which, in an operative position thereof, prevents the inlet member from being thrust prematurely to its advanced, injection position.

17. Apparatus according to any of claims 1 to 16, further including a refractory body for installation in the wall of a vessel, the body having a passage slidably receiving the feed pipe.

18. Apparatus according to claim 17, wherein an inner end of the passage has a dislodgeable closure fitted therein to prevent ingress of liquid into the passage from the vessel, wherein the feed pipe is spaced from the closure when the inlet member is retracted, and wherein the feed pipe is effective to dislodge the closure when the inlet member is moved to the advanced injection position.

19. Apparatus according to any of claims 1 to 18, wherein the bodies comprising the inlet member include coacting hardened bushes for shearing a treatment substance in the form of a wire or rod when the outboard body is displaced laterally from its companion body.

20. Apparatus according to claim 6 or any claim dependent on claim 6 directly or indirectly comprising a plurality of said feed pipes each fitted with one of said inlet members, the support means being adapted to support said inlet members in operative, retracted or advanced positions and a plurality of the injection-terminating means, one for each pipe/inlet member, and each injection-terminating means being operable independently of the others.

21. Apparatus according to claim 20, wherein the support means is adapted to support two feed pipes/inlet members and there are two injectionterminating means therefor.

22. Apparatus according to claim 21 in combination with a refractory body for installation in the wall of the vessel and with a mounting means for securing the support means in predetermined orientations to the vessel, the refractory body having a plurality of pairs of injection passages and the support means being mountable selectively to the vessel in any one of an equal plurality of orientations such that two feed pipes supported thereby can be located in any of the pairs of passages in the refractory body.

23. Apparatus for use in introducing one or more treatment substances through the wall of a vessel into a high temperature liquid (e.g. a metal melt) contained therein, substantially as herein described with reference to and as shown in the accompanying drawings.