AU2009272845A1 - Apparatus for insertion and extraction of fuel injection lances into and out of the tuyere stock of a blast furnace - Google Patents

Description

WO 2010/006977 PCT/EP2009/058683 1 APPARATUS FOR INSERTION AND EXTRACTION OF FUEL INJECTION LANCES INTO AND OUT OF THE TUYERE STOCK OF A BLAST FURNACE Technical field [0001] The present invention generally relates to the installation of fuel injection lances on a tuyere stock of a blast furnace. More specifically, the invention relates to the insertion and extraction procedure of fuel injection lances, especially of oxy coal injection lances, into and out of the tuyere stock. Background Art [0002] Fuel injection lances are used for injecting a combustible, e.g. pulverized coal, into the hot wind that is guided through a tuyere stock into a blast furnace. Such lances need to be replaced periodically for maintenance and repair purposes, for example because of excessive wear or destruction of the tip of the lance as a consequence of combustion and abrasion. [0003] Currently, the typical procedure for exchanging a fuel injection lance, i.e. extraction of a lance that requires servicing and insertion of a new or refurbished lance, requires manual intervention of three to four human operators. According to the typical procedure, the human operators disconnect, extract, insert and connect the lance by purely manual labor. [0004] Due to the dimension (see size proportion of lance with respect to human operator in FIG.2) and considerable weight of an injection lance and also due to the requirement for adequate axial alignment, both insertion and extraction of a lance tend to be relatively cumbersome and time consuming. The time required for exchanging an injection lance causes an undesirable duration of human exposure to the harsh environment of the furnace, especially when considering multiplication of the required intervention time due the number of tuyere stocks in a typical blast furnace plant, and the fact that each tuyere stock may have several associated lances. [0005] The above problem is even more pronounced in case of oxy-coal injection lances, which currently find increasingly widespread use for taking advantage of simultaneously injecting pulverized coal and oxygen into the hot WO 2010/006977 PCT/EP2009/058683 2 blast. This is because oxy-coal lances have both increased weight and increased diameter compared to conventional lances. Due to the increased diameter, the required force for inserting an oxy-coal injection lance against the force exerted by the hot blast pressure (typically in the order of 4-5bar) may well exceed 400N, thus rendering the current practice for exchanging oxy-coal lances even more cumbersome and thereby time consuming. [0006] Korean patent application KR 10 2004 0019479 discloses an apparatus designed for pulling a pulverized coal injection lance out of a tuyere stock. This apparatus comprises a guide frame with a lance holder that is moveable lengthwise along the guide frame by means of a chain drive. The guide frame is supported on a wheeled cart by means of a contrivance allowing motorized adjustment of the inclination angle of the guide frame. The apparatus according to KR 10 2004 0019479 is further configured to rectify an injection lance that has been bent during insertion and comprises, to this effect, a lance correcting frame fixed to one end of the guide frame. To be rectified, the injection lance passes through the lance-correcting frame when the lance is pulled out by driving the lance holder. Whilst such apparatus appears to facilitate extraction of an injection lance, especially of a bent lance, it does not notably facilitate insertion. Technical problem [0007] In view of the situation set out hereinabove, it is a first object of the present invention to provide a solution allowing rapid and reliable exchange of a fuel injection lance on a tuyere stock by facilitating extraction as well as insertion. This object is achieved by an apparatus as claimed in claim 1. General Description of the Invention [0008] An apparatus according to claim 1 is designed for insertion and extraction of a fuel injection lance into and out of a tuyere stock on a shaft furnace, in particular on a blast furnace. The tuyere stock comprises a lance sheath or lance holder that defines an insertion/extraction axis on which the lance is to be aligned for insertion/extraction. The lance sheath or lance holder is mounted in coaxial extension of a lance channel, which typically passes through the blowpipe or WO 2010/006977 PCT/EP2009/058683 3 through the tuyere of the tuyere stock, and through which an injection lance can be inserted into the tuyere stock for injecting a combustible into the hot blast. [0009] The proposed apparatus essentially includes a linear guide, a guided carriage, the guide including a mechanism for moving the carriage, and a mounting support for removably attaching the linear guide to the tuyere stock. [0010] More specifically, the carriage is movably supported by the linear guide and cooperates with a connecting device for connecting an injection lance to the carriage so that the injection lance can be moved axially along and more precisely on a translation axis. Accordingly, the mechanism in the linear guide is configured for linearly moving the carriage along and on a guide axis. As proposed in claim 1, the linear guide has a first coupling half for mounting the linear guide to the tuyere stock, whereas the mounting support has a cooperating second coupling half cooperating for removably attaching the linear guide to the tuyere stock. The mounting support and the two coupling halves are configured to orient the linear guide so that the guide axis of the linear guide is parallel to the insertion/extraction axis and so that the translation axis of an injection lance connected to the carriage is coaxial with the insertion/extraction axis when the linear guide is attached to the tuyere stock via the mounting support. [0011] By facilitating alignment of the lance and by enabling actuated insertion/extraction, the apparatus enables a reduction of the time required for replacement of fuel injection lances. Furthermore, the apparatus allows reducing the required man power from usually three to four operators required for fully manual replacement, to at most two operators. [0012] Preferably, the mounting support bears all the weight of an attached linear guide and of a connected injection lance prior to its insertion. That is to say, the mounting support is preferably configured to support an attached linear guide together with a connected injection lance in cantilevered manner on the tuyere stock. Accordingly, besides attaching the linear guide to the mounting support and connecting the injection lance to the guide, no further means and measures are required for properly mounting and supporting the guide and the injection lance. [0013] In a preferred embodiment, the mechanism in the linear guide is configured to be self-locking in axial direction so as to avoid unwanted linear WO 2010/006977 PCT/EP2009/058683 4 motion of the carriage along the guide axis, such that the carriage cannot be driven by forces external to the mechanism. This embodiment increases safety, since it prevents the risk of lance ejection due to the hot blast pressure during insertion/extraction i.e. during the time the injection lance is secured to the apparatus only. [0014] According to a reliable and straightforward embodiment, the mechanism of the linear guide is a linear transmission of the spindle drive type. In this embodiment, the mechanism includes a spindle that is mounted rotatable about the guide axis inside the linear guide. The carriage comprises a spindle nut engaging the spindle and mounted on the carriage for linearly moving the carriage by rotation of the spindle. Preferably, a self-locking spindle arrangement is used by appropriate choice of mating of material (of spindle and spindle nut) and of the lead angle of the spindle. In alternative embodiments, the mechanism can comprise a chain drive, a belt drive or a rack-and-pinion gear, with the carriage being appropriately connected to the chain, the belt or the pinion for linearly moving the carriage by actuation of the drive or gear. Also in this case, the mechanism is advantageously self-locking to prevent lance ejection, e.g. by associating a self-locking brake to the drive such as a self-locking worm gear. An actuator may be permanently or removably coupled to the mechanism for actuating the carriage and thereby translating the lance. [0015] Preferably, the first coupling half and the second coupling half (of the linear guide and the mounting support respectively) comprise a rapid action fastener to allow quick attaching and detaching of the linear guide onto and from the tuyere stock. In the latter case, the rapid action fastener preferably comprises a lever actuated fastening stirrup, which can be arranged either on the first coupling half or on the second coupling half, and a cooperating hook, which can be arranged on the second coupling half respectively on the first coupling half, for attaching the linear guide to the mounting support. Furthermore, in this embodiment the apparatus may further comprise a stud on either of the coupling halves and a claw on the other coupling half, the claw being configured to engage the stud so as to block the linear guide on the mounting support.

WO 2010/006977 PCT/EP2009/058683 5 [0016] In installed condition, the mounting support is permanently or removably fixed to the tuyere stock, in particular to the lance sheath. Preferably, the second coupling half comprises an abutment, more particularly an abutment plate. The abutment plate defines an abutment surface that is, in a simple but not strictly necessary configuration, substantially perpendicular to the insertion/extraction axis defined by the lance sheath. Correspondingly, the first coupling half preferably comprises a counter abutment, in particular a counter abutment plate, defining a counter abutment surface, which, in a simple configuration, is perpendicular to the guide axis. The latter embodiment presents a simple solution for providing inherent alignment as set out above. [0017] The apparatus advantageously comprises a separate connecting device for connecting an injection lance to the carriage, such that a dedicated connecting device can be mounted to each injection lance, thus enabling further timesaving. In simple configuration, the carriage comprises a first connecting portion whereas the connecting device comprises a second connecting portion connectable to the first connecting portion. In the latter case, the connecting device preferably has a collar for radially and axially securing an injection lance and such that the injection lance can be moved axially on the translation axis by the carriage when the first and second connecting portions are engaged. [0018] Preferably, the linear guide comprises at least one elongated beam defining a linear track and a carriage that is movably supported on the linear track of the beam, e.g. by means of a roller arrangement or a sliding guide. [0019] Advantageously, the linear guide is dimensioned such that the travel of the carriage is greater than the insertion depth of an injection lance. [0020] As will be appreciated the proposed apparatus is particularly suited for industrial application in the exchange procedure of fuel injection lances, in particular oxy-coal injection lances, on the tuyere stock of a blast furnace. Brief Description of the Drawings [0021] A preferred embodiment of the invention is described hereinafter, by way of example, with reference to the accompanying drawings in which: WO 2010/006977 PCT/EP2009/058683 6 FIG.1 is a side view of a conventional tuyere stock arrangement according to the prior art showing a fuel injection lance in inserted position; FIG.2 is a side view according to FIG.1 showing the fuel injection lance in extracted position and illustrating a human operator as dimension reference; FIG.3 is an isometric perspective view of an apparatus according to the invention for insertion and extraction of a fuel injection lance into and out of a tuyere stock as shown in FIGS.1-2; FIG.4 is an enlarged partial isometric perspective view of the apparatus of FIG.3, in operative position on the tuyere stock illustrating the connection of a linear guide to a mounting support by means of a rapid action fastener; FIG.5 is an enlarged partial isometric perspective view of the apparatus of FIG.3, in non-operative position with the linear guide disconnected from the mounting support. [0022] Further details and advantages of the present invention will become apparent from the following detailed description. Detailed Description with Reference to the Drawings [0023] FIG.1 schematically shows a conventional tuyere stock, generally identified by reference numeral 1. The tuyere stock 1 comprises a tuyere 2, which forms the downstream tip of the tuyere stock 1 and through which hot blast is blown into a blast furnace (not shown). The tuyere 2 is supported inside a tuyere cooler holder 3, which is fixed to the shell of the furnace and does not form part of the tuyere stock 1 that is suspended moveably with respect to the furnace. The tuyere stock 1 further includes a blowpipe 4 connected upstream of the tuyere 2 and an elbow 5 connected upstream of the blowpipe 4. The elbow 5 may comprise a sight hole arrangement (not shown) in axial alignment with the tuyere 2. The elbow 5 of the tuyere stock is connected by means of a downleg 6 to a hot blast bustle pipe (not shown) from which hot blast is fed, through the downleg 6, the elbow 5 and the blowpipe 4, i.e. through the piping conduit formed by the tuyere stock 1, for injection into the furnace through the tuyere 2.

WO 2010/006977 PCT/EP2009/058683 7 [0024] FIG.1 further shows a fuel injection lance 10, such as a pulverized coal or an oxy-coal injection lance, inserted into and fastened to a lance insertion sheath 12 (also called lance holder) and additionally secured to the lance sheath 12 by means of a retention chain 14. The injection lance 10 as such is of any known suitable configuration and serves to inject a combustible into the hot blast. The lance sheath 12 as such is also of any known suitable configuration, e.g. of basically tubular configuration, and serves amongst others as guide for insertion and extraction of the injection lance 10. The lance sheath 12 also comprises a suitable valve arrangement, e.g. including a ball valve 16 and a non-return valve 17, as shown in FIGS.1-2, for preventing hot blast from escaping through the lance sheath 12 when the injection lance 10 is extracted. For the purposes of the present disclosure, the lance sheath 12, since it is fixed to the tuyere stock 1 and immobile relative to the latter, is considered to be an integral part of the tuyere stock 1. [0025] In the embodiment of FIGS.1-2, the lance sheath 12 is flanged to a boss 15 projecting obliquely from the blowpipe 4. The lance sheath 12 is mounted in aligned extension of a lance channel (not shown) passing through the boss 15 and obliquely through the wall of the blowpipe 4 so as to allow insertion of the lance 10 into the hot blast passage inside the blowpipe 4. Although not shown in FIGS.1-2, it will be appreciated that the lance sheath 12 may alternatively be connected directly to the tuyere 2 for insertion of the lance 10 into the passage defined by the tuyere 2, as disclosed for example in U.S. Patent 5,451,034, the disclosure of which is incorporated herein by reference. It will also be understood that, while only one injection lance 10 and corresponding lance sheath 12 are shown, the tuyere stock 1 may comprise one or more further injection lances, each inserted through a corresponding sheath. [0026] FIG.2 shows the fuel injection lance 10 in extracted position. In known manner, the lance 10 has a tip end 18 forming an injection nozzle and a rear end 19 comprising conduit connection, e.g. for connecting the lance to a pneumatic pulverized coal feeding system, and, in case of an oxy-coal lance, to an oxygen source for injection of oxygen together with pulverized coal into the hot blast.

WO 2010/006977 PCT/EP2009/058683 8 [0027] Turning now to FIGS.3-5, an apparatus for insertion and extraction of the fuel injection lance 10 into and out of the tuyere stock 1 will be described. The apparatus, generally identified by reference numeral 20, is designed for permitting rapid transfer of the injection lance 10 between an inserted position as shown in FIG.1 and an extracted position as shown in FIG.2 and vice-versa. [0028] The apparatus 20, as completely shown in FIG.3, comprises a linear guide 22 with a carriage 24 movably supported therein. The linear guide comprises two parallel U-shaped beams 26, 28 fixed together by means of a head part 30 and a foot part 32 so as to form a rigid hollow frame resistant to bending. The U-shaped beams 26, 28 are held apart at a small distance and with parallel and adjacent flange edges by means of the head part 30 and the foot part 32, to which the flanges are fixed, e.g. by means of a screw connection. As seen in FIG.3, the lower flanges of the U-shaped beams 26, 28 form a track supporting four rollers 34 of the carriage 24. The linear guide 22 guides the carriage 24 in linear manner and further comprises a mechanism for imparting linear motion to the carriage 24 along a guide axis 35. In the embodiment shown in FIGS.4-5, this mechanism comprises a threaded spindle 36 extending from the head part 30 to the foot part 32 and supported to be rotatable about the guide axis 35 but axially fixed by means of suitable bearings arranged in the head part 30 and the foot part 32 respectively, e.g. by means of a castellated nut (not shown) in the foot part 32 and a shoulder produced by transverse turning (not shown) in the head part 30. The mechanism further comprises a spindle nut 38 mounted to the frame of the carriage 24 with the nut axis being coaxial to the guide axis 35 and parallel to the rolling direction of rollers 34. The spindle nut 38 is preferably pivot-mounted to the carriage 24 such that it is pivotable on an axis perpendicular to the spindle 36 and parallel to the axes of the rollers 34 in order to avoid blocking of the spindle nut 38. Rotation of the spindle 36 causes axial translation of the carriage 24 on the guide axis 35. The travel 37 of the carriage 24 is determined by the length of the spindle 36, the length of the beams 26, 28 and the distance between the head part 30 and the foot part 32, and is chosen to slightly exceed the insertion depth of fuel injection lances 10.

WO 2010/006977 PCT/EP2009/058683 9 [0029] Although not shown in FIG.3, it will be appreciated that a coupler 40 is fixed to the spindle 36 at the rearward end of the foot part 32, e.g. on a projecting portion of the spindle 36 for transmitting torque to the spindle 36 by means of an external actuator such as e.g. an electric or pneumatic impact wrench or a crank. In other words, the coupler 40 (not shown) serves to actuate the mechanism in the linear guide 22 for imparting linear motion to the carriage 24. Being adapted for the use of machine tools, the apparatus 20 allows effortless and rapid insertion of injection lances, even of considerable diameter, such as oxy-coal lances, and against considerable hot blast pressures. [0030] As will be appreciated, the spindle mechanism in the linear guide 22 is designed to be self-locking (or irreversible), i.e. such that potential translation of the carriage 24 by external action (e.g. hot blast pressure exerted onto the sealed cross-section of the injection lance 10) cannot rotate the spindle 36, thereby preventing unwanted motion of the carriage 24 and consequently also of a connected injection lance 10. This is achieved by appropriate choice of the material of the spindle 36 and the spindle nut 38 (appropriate mating of material) and by choosing a spindle 36 having a lead angle appropriate for self-locking. Consequently, the force exerted by the hot blast pressure onto an inserted but unsecured injection lance 10, e.g. during extraction, cannot cause ejection of the injection lance 10. While a spindle type mechanism is considered a preferred embodiment, alternative mechanisms are also within the scope of the present invention, e.g. a chain drive or a belt drive with a carriage fixed to the belt or chain or a rack-and-pinion gear mechanism (cogwheel mechanism) with the pinion arranged on the carriage and the rack arranged on the linear guide. Such alternative mechanisms also preferably include an associated self locking brake, such as for example a releasable ratchet brake or a self-locking (irreversible) worm gear preventing unwarranted carriage motion in the extraction direction. [0031] As further seen in FIG.3, the apparatus 20 comprises a connecting device 42 for connecting the injection lance 10 to a first connecting portion 44, e.g. in the form of two spaced apart parallel bolt support brackets, fixed to the carriage 24 and projection through the gap between the lower flanges of the U-shaped beams 26, 28. As best illustrated in FIG.5, the connecting device 42 comprises a WO 2010/006977 PCT/EP2009/058683 10 collar 46 embracing the injection lance 10 and second connecting portion 48 connectable to the first connecting portion 44 on the carriage 24, e.g. in the form of a projecting transverse rib with a through hole for bolted connection to the support brackets as illustrated in FIG.5. The collar 46 is configured to secure the injection lance 10 to the carriage 24 in radial and axial direction with respect to the lance axis. While the collar 46 may be configured as a clamp, fixedly clamped to the injection lance 10 by means of a screwed connection as shown in FIG.5, or welded to the injection lance 10, in an alternative preferred variant, the collar can be configured such that it is rotatable on the injection lance 10 with little radial play about the lance axis. The latter variant avoids the need to rotate the injection lance 10 for proper connection to the carriage 24. In this latter variant, two retainer rings (not shown) can be clamped or welded onto the injection lance 10 adjacently to and on either side of the collar for axially securing the collar. As will be noted, each injection lance 10 may be provided with a dedicated connection device 42 to enable additional timesavings. [0032] When the injection lance 10 is connected to the carriage 24 of the attached linear guide 22 by means of the connection device 42 (and when its tip end 18 is inserted into the lance sheath 12), the longitudinal axis of the injection lance 10 is parallel to the guide axis 35, as seen in FIG.3. It will also be appreciated that, in the latter configuration, the longitudinal axis of the injection lance 10 inherently coincides with i.e. is coaxial to the insertion/extraction axis 49 defined by the lance sheath 12, i.e. the axis on which the injection lance 10 must be aligned in order to be inserted/extracted through the lance sheath 12 and through the lance channel (not shown e.g. in the blowpipe 4) without jamming. [0033] As will be appreciated, the apparatus 20 allows translating the injection lance 10 connected to the carriage 24 on a translation axis (coinciding with the longitudinal axis of the injection lance 10) that is coaxial to the insertion/extraction axis 49, when the linear guide 22 is attached to the tuyere stock 1, e.g. to the lance sheath 12 as shown in FIG.3. Connection of the linear guide 22 to the tuyere stock 1 is made by means of a mounting support 50 as best illustrated in FIG.4, which represents an enlarged view of a portion of FIG.3 (portion indicated by solid line circle).

WO 2010/006977 PCT/EP2009/058683 11 [0034] As seen in FIG.4, the mounting support 50 of the apparatus 20 comprises two stanchion flanges 52 that are fixed to the lance sheath 12 by means of a pipe clamp type screw connector 54. In an alternative equally preferred embodiment, the mounting support 50 can be permanently fixed to a component of the tuyere stock 1, e.g. to the lance sheath 12 as shown in FIGS.3-5 by means of a welded assemblage. The mounting support 50 further comprises an abutment plate 56 supported by the stanchion flanges 52. The abutment plate 56 is arranged to define an abutment surface 57 that is perpendicular to the insertion/extraction axis 49 in the illustrated embodiment. The mounting support 50 further comprises a retainer edge 58 integrally formed with or fixed to the abutment plate 56 on its upper end and a hook 60 fixed to the top face of the abutment support 50. A pair of claws 62 is integrally formed with or fixed to the abutment plate 56 so as to project transversely, one claw 62 being provided on either side. [0035] As best illustrated in FIG.5, the linear guide 22 comprises a counter abutment plate 64 defining a counter abutment surface 65 that is perpendicular to the guide axis 35, i.e. the rotation axis of the spindle 36. It will be understood that, as long as alignment of the linear guide 22 and consequently the lance 10 is warranted, surfaces 57, 65 need not necessarily be perpendicular to the respective axes. A stud 66, in the form of a cylindrical bar, is integrally formed with or fixed to the lower side of the counter abutment plate 64 so as to protrude laterally. The linear guide further comprises, as best illustrated in FIG.3, a lever 68, which is hinged to the head part 30, and to which a U-shaped stirrup 70 of adjustable reach is hinged in eccentric manner. [0036] The lever actuated stirrup 70 and the hook 60 together form a rapid action fastener for rapidly fasting the linear guide 22 to the coupling support 50. As will also be understood, the counter abutment plate 64 and the stud 66 together with the stirrup 70 form a first coupling half on the linear guide 22 for securely but removably attaching the latter in predetermined orientation to the tuyere stock 1, more precisely to the mounting support 50. Correspondingly, the cooperating elements of the mounting support 50, i.e. the abutment plate 56, the pair of claws 62 and the hook 60 form a second coupling half, which cooperates with the coupling half on the linear guide 22 to allow rapid and secure attachment and WO 2010/006977 PCT/EP2009/058683 12 correct orientation (aligned) of the linear guide 22. FIG.4 best illustrates the coupling halves in engaged i.e. coupled configuration, whereas an exemplary detached configuration of the coupling halves is shown in FIG.5. In engaged condition as shown in FIGS.3-4, the claws 62 engaging the stud 66 prevent any rotation of the linear guide 22 about its guide axis 35 as well as any lateral or downward motion whereas the retainer edge 58 retains the counter abutment plate 64 in upward direction. As will be noted, for each tuyere stock 1 on a furnace, each access port for an injection lance 10 is preferably provided with a dedicated mounting support 50, so as to enable further timesaving. [0037] Due to the geometric configuration of the mounting support 50 and its predetermined orientation with respect to the tuyere stock 1, the guide axis 35 of the mounted linear guide 22 is oriented in parallel to the insertion/extraction axis 49 and such that the longitudinal (and translation) axis of any injection lance connected to the linear guide 22 is coaxial to this insertion/extraction axis 49, as clearly apparent from FIG.3. Hence, no time is lost for orienting the injection lance 10 appropriately, when using the apparatus 20. As further clearly apparent from FIG.3, the mounting support 50 is configured to support the weight of the linear guide 22 and a connected injection lance. Accordingly, in mounted condition as shown in FIG.3, the linear guide 22 is supported in cantilevered manner on the tuyere stock 1 by means of the mounting support 50. [0038] The replacement procedure of an injection lance 10 by use of the apparatus 20 is set out below. Initially, the linear guide 22 is coupled to the mounting support 50 by inserting the stud 66 into the claws 62, pivoting the counter abutment surface 64 into contact with the abutment surface 57 and subsequently closing the rapid action fastener (i.e. engaging the stirrup 70 into the hook 60 by means of lever 68). Thereby, the linear guide 22 is (removably) attached to the tuyere stock 1 and its guide axis 35 is oriented in parallel with the insertion/extraction axis 49. In the next step, the carriage 24 is brought into a position that allows connecting the currently inserted injection lance 10 that is to be serviced or discarded to the carriage by means of the connecting device 42. Once the injection lance 10 is secured to the carriage 24 by engagement of the connecting portions 44, 48, the sleeve nut 72 of the stuffing box 74 is unscrewed WO 2010/006977 PCT/EP2009/058683 13 and the retention chain 14 (see FIG.1, not shown in FIGS.3-5) can be released. As will be understood, the self locking configuration of the translation mechanism in the linear guide 22 prevents any unintentional ejection of the now unsecured injection lance 10. By actuation of the mechanism of the linear guide 22, more specifically by rotating the spindle 36 with a machine wrench using the coupler 40, the injection lance 10 can now be extracted safely and rapidly. Once it has passed the ball valve 16, the latter is closed. A catch 76 fixed to the linear guide 22 prevents dropping of the tip end 18 of the completely extracted injection lance 10. [0039] After the used injection lance 10 has been extracted, a new or refurbished lance is inserted also by means of the apparatus 20. The apparatus 20 still being installed, a new injection lance is connected to the carriage 24 after the previous lance has been detached and the carriage 24 has been brought in a position close to the foot part 32. The tip end 18 of the new injection lance 10 is then placed above the catch 76. Depending on the type of connecting device 42 the tip end 18 is then manually introduced into the access port of the lance sheath 12 at the stuffing box 74 while the injection lance 10 is translated in insertion direction by the carriage 24 due to actuation of the spindle 36. Before the tip end 18 passes the ball valve 16, the latter is opened. Then the injection lance 10 is fully inserted through the lance sheath 12 and the lance channel (not shown) to reach its final position at full insertion depth by actuation of the carriage 24. Once the injection lance is in fully inserted position, the stuffing box 74 is closed by means of the sleeve nut 72 and the chain 14 (see FIG.1) is engaged. Thereafter, the connecting device 42 can be disconnected from the carriage 24, and the linear guide 22 can be rapidly detached from the mounting support 50 using the rapid action fastener 60, 70. The linear guide is then available for further use, e.g. on a different mounting support 50 at a different lance location.

Claims (15)

1. An apparatus for insertion and extraction of a fuel injection lance, in particular an oxy-coal injection lance, into and out of a tuyere stock of a shaft furnace, in particular of a blast furnace, said tuyere stock comprising a lance sheath that defines an insertion/extraction axis and is mounted in coaxial extension of a lance channel through which an injection lance can be inserted into said tuyere stock, said apparatus comprising: a linear guide and a carriage movably supported by said linear guide, said carriage cooperating with a connecting device for connecting an injection lance to said carriage such that said injection lance can be moved axially along a translation axis by said carriage, said linear guide comprising a mechanism for linearly moving said carriage along a guide axis and a first coupling half for mounting said linear guide to said tuyere stock; and a mounting support having a second coupling half cooperating with said first coupling half of said linear guide for removably attaching said linear guide to said tuyere stock; said mounting support, said first coupling half and said second coupling half being configured to orient said linear guide so that said guide axis of said linear guide is parallel to said insertion/extraction axis and so that the translation axis of an injection lance connected to said carriage is coaxial with said insertion/extraction axis when said coupling halves are engaged.

2. Apparatus according to claim 1, wherein said mounting support is configured to support said linear guide in cantilevered manner when said coupling halves are engaged.

3. Apparatus according to claim 1 or 2, wherein said mechanism is self-locking in axial direction to avoid unwanted linear motion of said carriage along said guide axis.

4. Apparatus according to claim 1, 2 or 3, wherein said mechanism comprises a spindle mounted rotatable about said guide axis in said linear guide and said carriage comprises a spindle nut arranged on said spindle for linearly moving said carriage by rotation of said spindle, wherein the mating of material of said WO 2010/006977 PCT/EP2009/058683 15 spindle and said spindle nut as well as the lead angle of said spindle are preferably chosen such that said mechanism is self-locking.

5. Apparatus according to claim 1, 2 or 3, wherein said mechanism comprises a chain drive or a belt drive or a rack-and-pinion gear arrangement configured for linearly moving said carriage and preferably configured to be self-locking.

6. Apparatus according to any one of the preceding claims, wherein said first coupling half and said second coupling half comprise a rapid action fastener.

7. Apparatus according to claim 6, wherein said rapid action fastener comprises a lever actuated fastening stirrup on said first coupling half or on said second coupling half and a hook on said second coupling half respectively on said first coupling half, said hook cooperating with said fastening stirrup for attaching said linear guide to said mounting support.

8. Apparatus according to claim 6 or 7, further comprising a stud on said first coupling half or on said second coupling half and a claw on said second coupling half respectively on said first coupling half, said claw being configured to engage said stud so as to block said linear guide on said mounting support.

9. Apparatus according to any one of the preceding claims, wherein said mounting support is permanently or removably fixed to said tuyere stock, in particular to said lance sheath, and wherein said second coupling half comprises an abutment, more particularly an abutment plate, defining an abutment surface that is preferably perpendicular to said insertion/extraction axis defined by said lance sheath.

10. Apparatus according to claim 9, wherein said first coupling half comprises a counter abutment, in particular a counter abutment plate, defining a counter abutment surface that is preferably perpendicular to said guide axis.

11. Apparatus according to any one of the preceding claims, further comprising a connecting device for connecting an injection lance to said carriage.

12. Apparatus according to claim 11, wherein said carriage comprises a first connecting portion and wherein said connecting device comprises a collar for radially and axially securing an injection lance and a second connecting portion connectable to said first connecting portion such that said injection lance can be moved axially along said translation axis by said carriage. WO 2010/006977 PCT/EP2009/058683 16

13. Apparatus according to any one of the preceding claims, wherein said linear guide comprises at least one elongated beam defining a linear track, said carriage carriage being movably supported on said linear track of said beam.

14. Apparatus according to any one of the preceding claims, wherein said linear guide is dimensioned such that the travel of said carriage is greater than the insertion depth of an injection lance.

15. Use of the apparatus according to any one of the preceding claims for exchanging fuel injection lances, in particular oxy-coal injection lances, on the tuyere stock of a blast furnace.