U.S. patent application number 13/054135 was filed with the patent office on 2011-05-12 for apparatus for insertion and extraction of fuel injection lances into and out of the tuyere stock of a furnace blast.
This patent application is currently assigned to PAUL WURTH S.A.. Invention is credited to Paul Goedert, Patrick Hutmacher, Christian Lunkes, Ben Muller.
Application Number | 20110109024 13/054135 |
Document ID | / |
Family ID | 40445598 |
Filed Date | 2011-05-12 |
United States Patent
Application |
20110109024 |
Kind Code |
A1 |
Muller; Ben ; et
al. |
May 12, 2011 |
APPARATUS FOR INSERTION AND EXTRACTION OF FUEL INJECTION LANCES
INTO AND OUT OF THE TUYERE STOCK OF A FURNACE BLAST
Abstract
An apparatus for insertion and extraction of a fuel injection
lance into and out of a tuyere stock (1) of a shaft furnace, in
particular of a blast furnace, is proposed, the tuyere stock
includes 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 the tuyere stock
where the proposed apparatus includes a linear guide, a carriage
and a mounting support, the carriage is movably supported by the
linear guide and cooperates with a connecting device for connecting
an injection lance to the carriage such that the injection lance
can be moved axially along a translation axis by the carriagee,
where the linear guide includes a mechanism for linearly moving the
carriage along a guide axis and a first coupling half for mounting
the linear guide to the mounting support attached to the tuyere
stock, the mounting support having a second coupling half
cooperating with the first coupling half of the linear guide for
removably attaching the linear guide to the tuyere stock, the
mounting support and the coupling halves orienting an attached
linear guide so that the guide axis of the linear guide in 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.
Inventors: |
Muller; Ben; (Schrondweiler,
LU) ; Goedert; Paul; (Mondorf-Les-Bains, LU) ;
Lunkes; Christian; (Ehlerange, LU) ; Hutmacher;
Patrick; (Bettembourg, LU) |
Assignee: |
PAUL WURTH S.A.
Luxembourg
LU
|
Family ID: |
40445598 |
Appl. No.: |
13/054135 |
Filed: |
July 8, 2009 |
PCT Filed: |
July 8, 2009 |
PCT NO: |
PCT/EP2009/058683 |
371 Date: |
January 14, 2011 |
Current U.S.
Class: |
266/265 |
Current CPC
Class: |
F27D 1/18 20130101; C21B
7/16 20130101; F27B 1/16 20130101 |
Class at
Publication: |
266/265 |
International
Class: |
C21B 7/16 20060101
C21B007/16 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 14, 2008 |
LU |
LU 91462 |
Claims
1.-15. (canceled)
16. An apparatus for insertion and extraction of a fuel injection
lance, in particular of an oxy-coal injection lance, into and out
of a shaft furnace tuyere stock, in particular of a blast furnace
tuyere stock, that comprises a lance sheath that defines an
insertion/extraction axis and that is mounted in coaxial extension
of a lance channel, through which an injection lance can be
inserted, said apparatus comprising: a linear guide with 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 carriage can move said injection lance
axially along a translation axis, 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, wherein
said second coupling half comprises an abutment and said first
coupling half comprises a counter-abutment; said first coupling
half and said second coupling half further comprising a rapid
action fastener for fastening together said abutment and said
counter-abutment, wherein said abutments and said mounting support
are 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, when
connected to said carriage, is coaxial with said
insertion/extraction axis when said coupling halves are
engaged.
17. Apparatus according to claim 16, wherein said mounting support
is configured to support said linear guide in cantilevered manner
when said coupling halves are engaged.
18. Apparatus according to claim 16, 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.
19. Apparatus according to claim 18, wherein the mating of material
of said spindle and said spindle nut and/or the lead angle of said
spindle are chosen such that said mechanism is self-locking.
20. Apparatus according to claim 16, 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
configured to be self-locking to avoid unwanted linear motion of
said carriage along said guide axis.
21. Apparatus according to claim 16, wherein said rapid action
fastener comprises a lever-actuated fastening stirrup, which is
arranged either on said first coupling half or on said second
coupling half, and a hook, which is arranged 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.
22. Apparatus according to claim 21, 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.
23. Apparatus according to claim 16, wherein said mounting support
is fixed to a tuyere stock and wherein said abutment of said second
coupling half is formed by an abutment plate that defines an
abutment surface that is substantially perpendicular to said
insertion/extraction axis defined by said lance sheath.
24. Apparatus according to claim 23, wherein said mounting support
is removably fixed to said lance sheath of said tuyere stock.
25. Apparatus according to claim 23, wherein said counter-abutment
of said first coupling is a counter abutment plate that defines a
counter-abutment surface that is substantially perpendicular to
said guide axis.
26. Apparatus according to claim 16, further comprising an
injection lance having a connecting device that cooperates with
said carriage and connects said injection lance to said
carriage.
27. Apparatus according to claim 26, wherein said carriage
comprises a first connecting portion and wherein said connecting
device comprises a collar for radially and axially securing said
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.
28. Apparatus according to claim 16, wherein said linear guide
comprises at least one elongated beam defining a linear track, said
carriage being movably supported on said linear track of said
beam.
29. Apparatus according to claim 16, wherein said linear guide is
dimensioned such that the travel of said carriage is greater than
the insertion depth of an injection lance.
30. Tuyere stock of a blast furnace comprising an apparatus for
insertion and extraction of a fuel injection lance into and out of
said tuyere stock, said tuyere stock being equipped with a lance
sheath and with a lance channel, through which an injection lance
can be inserted, said lance sheath having an insertion/extraction
axis and that is in coaxial extension of said lance channel, and
said apparatus comprising: a linear guide with a carriage movably
supported by said linear guide, said carriage being configured for
connecting an injection lance to said carriage such that said
carriage can move said injection lance axially along a translation
axis, 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 fixed to said tuyere stock and 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,
wherein said second coupling half comprises an abutment and said
first coupling half comprises a counter-abutment; said first
coupling half and said second coupling half further comprising a
fastener for fastening together coupling halves wherein said
abutments and said mounting support are configured to orient said
linear guide so that said guide axis of said linear guide is
parallel to said insertion/extraction axis of said lance sheath and
so that the translation axis of an injection lance, when connected
to said carriage, is coaxial with said insertion/extraction axis
when said coupling halves are engaged.
31. The tuyere stock according to claim 30, further comprising an
oxy-coal injection lance connected to said carriage.
32. The tuyere stock according to claim 30, wherein said mounting
support is removably fixed to said lance sheath of said tuyere
stock and thereby fixed to said tuyere stock.
33. The tuyere stock according to claim 30, wherein said fastener
is configured as a rapid action and comprises a lever-actuated
fastening stirrup, which is arranged either on said first coupling
half or on said second coupling half, and a hook, which is arranged
on said second coupling half respectively on said first coupling
half, said hook cooperating with said fastening stirrup for rapidly
attaching or detaching said linear guide to or from said mounting
support and wherein said fastener further comprises a stud, which
is arranged on said first coupling half or on said second coupling
half, and a claw, which is arranged 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.
34. The tuyere stock according to claim 30, wherein said abutment
of said second coupling half comprises an abutment plate that
defines an abutment surface that is substantially perpendicular to
said insertion/extraction axis defined by said lance sheath and
wherein said counter-abutment of said first coupling comprises a
counter-abutment plate that defines a counter-abutment surface that
is substantially perpendicular to said guide axis.
Description
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 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 4-5 bar) 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.
BRIEF SUMMARY
[0007] In view of the situation set out hereinabove, the invention
provides a solution allowing rapid and reliable exchange of a fuel
injection lance on a tuyere stock by facilitating extraction as
well as insertion.
[0008] An apparatus according to the invention 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 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. 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 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.
[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:
[0022] 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;
[0023] 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;
[0024] 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;
[0025] 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;
[0026] 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.
[0027] Further details and advantages of the present invention will
become apparent from the following detailed description.
DETAILED DESCRIPTION
[0028] 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.
[0029] 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.
[0030] 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. Pat. No. 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.
[0031] 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.
[0032] 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.
[0033] 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.
[0034] 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.
[0035] 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.
[0036] 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 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.
[0037] 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.
[0038] 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).
[0039] 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.
[0040] 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.
[0041] 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 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.
[0042] 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.
[0043] 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 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.
[0044] 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.
* * * * *