U.S. patent application number 12/995426 was filed with the patent office on 2011-04-07 for method for manufacturing a cooling plate for a metallurgical furnace.
This patent application is currently assigned to PAUL WURTH S.A.. Invention is credited to Nicolas Maggioli, Nicolas Mousel, Claude Pleimelding.
Application Number | 20110079068 12/995426 |
Document ID | / |
Family ID | 39734444 |
Filed Date | 2011-04-07 |
United States Patent
Application |
20110079068 |
Kind Code |
A1 |
Maggioli; Nicolas ; et
al. |
April 7, 2011 |
METHOD FOR MANUFACTURING A COOLING PLATE FOR A METALLURGICAL
FURNACE
Abstract
A method for manufacturing a cooling plate (10) for a
metallurgical furnace comprising the steps of providing a slab (11)
of metallic material, the slab (11) having a front face (14), an
opposite rear face (16) and four side edges; and providing the slab
(11) with at least one cooling channel (30) by drilling at least
one blind borehole (40) into the slab (11), wherein the blind
borehole (40) is drilled from a first edge (22) towards an opposite
second edge (24). In accordance with an important aspect of the
present invention, the method comprises the further steps of
deforming the slab (11) in such a way that a first edge region (46)
of the slab (11) is at least partially bent towards the rear face
(16) of the slab (11); and machining excess material from the front
and rear faces (14, 16) of the slab (11) to produce a cooling plate
(10) having a panel-like body (12) wherein an opening to the
cooling channel (30) is located in the rear face (16).
Inventors: |
Maggioli; Nicolas;
(Thionville, FR) ; Mousel; Nicolas; (Dudelange,
LU) ; Pleimelding; Claude; (Platen, LU) |
Assignee: |
PAUL WURTH S.A.
LUXEMBOURG
LU
|
Family ID: |
39734444 |
Appl. No.: |
12/995426 |
Filed: |
April 24, 2009 |
PCT Filed: |
April 24, 2009 |
PCT NO: |
PCT/EP2009/054937 |
371 Date: |
November 30, 2010 |
Current U.S.
Class: |
72/340 |
Current CPC
Class: |
F27D 1/12 20130101; F27D
2009/0048 20130101; C21B 7/10 20130101; F27D 2009/0062 20130101;
F27D 9/00 20130101 |
Class at
Publication: |
72/340 |
International
Class: |
B21D 28/00 20060101
B21D028/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 6, 2008 |
LU |
91453 |
Claims
1. A method for manufacturing a cooling plate for a metallurgical
furnace, said method comprising the steps of: providing a slab of
metallic material, said slab having a front face, an opposite rear
face and four side edges; and providing said slab with at least one
cooling channel by drilling at least one blind borehole into said
slab, wherein said blind borehole is drilled from a first edge
towards an opposite second edge; wherein the method further
comprises the steps of: deforming said slab in such a way that a
first edge region of said slab is at least partially bent towards
said rear face of said slab; and machining excess material from
said front and rear faces of said slab to produce a cooling plate
having a panel-like body wherein an opening to said cooling channel
is located in said rear face.
2. The method as claimed in claim 1, wherein, after machining
excess material from said front and rear faces of said slab, the
method comprises the additional step of: forming grooves and
intermittent lamellar ribs in said front face of said panel-like
body for anchoring a refractory brick lining.
3. The method as claimed in claim 2, wherein the grooves are formed
with a width that is narrower at an inlet of the groove than at a
base of the groove.
4. The method as claimed in claim 3, wherein the grooves are formed
with dovetail cross-section.
5. The method as claimed in claim 1, wherein the method comprises
the additional step of: providing a connection pipe for each
cooling channel formed in said panel-like body; aligning one end of
each connection pipe with an opening to the respective cooling
channel arranged in the rear face of the panel-like body; and
connecting said connection pipes to said rear face of said
panel-like body so as to create a fluid connection between each
connection pipe and its associated cooling channel.
6. The method as claimed in claim 5, wherein an adapter is arranged
between said panel-like body and said connection pipe, said adapter
having the form of a hollow truncated cone.
7. The method as claimed in claim 5, wherein said rear face of said
panel-like body, said connection pipe and, if applicable, said
adapter are connected together through soldering or welding.
8. The method as claimed in claim 1, further comprising the steps
of: providing said slab with a first cooling channel by drilling a
first blind borehole into said slab, wherein said first blind
borehole is drilled from said first edge towards said second edge;
providing said slab with a second cooling channel by drilling a
second blind borehole into said slab, wherein said second blind
borehole is drilled from said first edge towards said second edge;
wherein said first and second cooling channels are arranged in such
a way that their ends in a second edge region meet and form a fluid
communication between said first and second cooling channels.
9. The method as claimed in claim 1, further comprising the steps
of: providing said slab with a first cooling channel by drilling a
first blind borehole into said slab, wherein said first blind
borehole is drilled from said first edge towards said second edge;
providing said slab with a second cooling channel by drilling a
second blind borehole into said slab, wherein said second blind
borehole is drilled from said second edge towards said first edge;
wherein said first and second cooling channels are arranged in such
a way that their ends meet and form a fluid communication between
said first and second cooling channels.
10. The method as claimed in claim 1, further comprising the steps
of: providing said slab with a first cooling channel by drilling a
first blind borehole into said slab, wherein said first blind
borehole is drilled from said first edge towards said second edge,
wherein an end of said first blind borehole is arranged in a second
edge region of said slab; in said second edge region, drilling a
connecting bore extending from said rear face of said slab to said
end of said first blind borehole and forming form a fluid
communication between said first cooling channel and said
connecting bore.
11. The method as claimed in claim 1, wherein said cooling plate is
made of at least one of the following materials: copper, a copper
alloy or steel.
Description
TECHNICAL FIELD
[0001] The present invention generally relates to a method for
manufacturing a cooling plate for a metallurgical furnace.
BACKGROUND
[0002] Such cooling plates for a metallurgical furnace, also called
staves, are well known in the art. They are used to cover the inner
wall of the outer shell of the metallurgical furnace, as e.g. a
blast furnace or electric arc furnace, to provide: (1) a heat
evacuating protection screen between the interior of the furnace
and the outer furnace shell; and (2) an anchoring means for a
refractory brick lining, a refractory guniting or a process
generated accretion layer inside the furnace. Originally, the
cooling plates have been cast iron plates with cooling pipes cast
therein. As an alternative to cast iron staves, copper staves have
been developed. Nowadays, most cooling plates for a metallurgical
furnace are made of copper, a copper alloy or, more recently, of
steel.
[0003] Different production methods have been proposed for copper
stave coolers. Initially, an attempt was made to produce copper
staves by casting in moulds, the internal coolant channels being
formed by a sand core in the casting mould. However, this method
has not proved to be effective in practice, because the cast copper
plate bodies often have cavities and porosities, which have an
extremely negative effect on the life of the plate bodies. The
mould sand is difficult to remove from the channels and the
channels are often not properly formed.
[0004] A cooling plate made from a forged or rolled copper slab is
known from DE 2 907 511 C2. The coolant channels are blind
boreholes introduced by deep drilling the rolled copper slab. The
blind boreholes are sealed off by welding in plugs. Then,
connecting bores are drilled from the rear side of the plate body
into the blind boreholes. Thereafter, connection pipe-ends for the
coolant feed or coolant return are inserted into these connecting
bores and welded to the stave body. With these cooling plates, the
above-mentioned disadvantages related to casting are avoided. In
particular, cavities and porosities in the plate body are virtually
precluded. The above manufacturing method is however relatively
expensive both in labour and material. Furthermore, due to
considerable mechanical and thermal stress to which the stave
cooler is exposed, the different welded connection joints are
critical as regards fluid tightness. In addition, since the
channels are integral with the stave body, there is only one level
of separation between the coolant and the furnace interior, i.e. if
the stave body cracks open, coolant will leak. A leakage of coolant
fluid into the furnace however leads to a significant risk of
explosion and should therefore be avoided at all cost.
BRIEF SUMMARY
[0005] The invention provide an improved method for manufacturing a
cooling plate for a metallurgical furnace, wherein the method does
not display the aforementioned drawbacks.
[0006] A method for manufacturing a cooling plate for a
metallurgical furnace in accordance with the present invention
comprises the steps of providing a slab of metallic material, the
slab having a front face, an opposite rear face and four side
edges; and providing the slab with at least one cooling channel by
drilling at least one blind borehole into the slab, wherein the
blind borehole is drilled from a first edge towards an opposite
second edge. In accordance with an important aspect of the present
invention, the method comprises the further steps of deforming the
slab in such a way that a first edge region of the slab is at least
partially bent towards the rear face of the slab; and machining
excess material from the front and rear faces of the slab to
produce a cooling plate having a panel-like body wherein an opening
to the cooling channel is located in the rear face.
[0007] By bending the slab towards the rear face and subsequently
machining excess material from the front and rear faces of the
slab, the opening to the cooling channel is located in the rear
face. Compared to the prior art method, as e.g. described in DE 2
907 511 C2, it is no longer necessary to seal off the opening to
the cooling channel in the first edge by welding in a plug. Nor is
it necessary to drill a connecting bore between the rear face and
the cooling channel to access the cooling channel in the first edge
region. The removal of these process steps reduces both labour and
material costs.
[0008] More importantly, however, the absence of the plug provides
a more reliant cooling plate. Indeed, as the cooling plate is
exposed to considerable mechanical and thermal stress, in
particular in the edge regions of the cooling plate, the plug has
to be considered as a weak point. If the weld of the plug
deteriorates, fluid tightness of the cooling channel can no longer
be guaranteed and coolant could leak from the cooling channel into
the furnace. Such leakage of coolant fluid into the furnace should
however be avoided at all cost as it may lead to a significant risk
of explosion. As no such plug is welded to the cooling plate
manufactured according to the method of present invention, the risk
of a leakage occurring through such a plug is avoided. Furthermore,
the cooling plate manufactured according to the method of present
invention also presents a more important material thickness on the
front face in the first edge region, as compared to cooling plates
manufactured according prior art methods. The increased material
thickness also contributed to a longer lifetime of the cooling
plate.
[0009] Preferably, after machining excess material from the front
and rear faces of the slab, the method comprises the additional
step of forming grooves and intermittent lamellar ribs in the front
face of the panel-like body for anchoring a refractory brick
lining.
[0010] To warrant a good anchoring function of the lamellar ribs
and grooves structure on the front face of the cooling plate and a
good thermal form stability of the cooling plate, the grooves are
advantageously formed with a width that is narrower at an inlet of
the groove than at a base of the groove. The grooves may e.g. be
formed with dovetail cross-section.
[0011] Preferably, the method comprises the additional step of
providing a connection pipe for each cooling channel formed in the
panel-like body; aligning one end of each connection pipe with an
opening to the respective cooling channel arranged in the rear face
of the panel-like body; and connecting the connection pipes to the
rear face of the panel-like body so as to create a fluid connection
between each connection pipe and its associated cooling
channel.
[0012] An adapter may be arranged between the panel-like body and
the connection pipe, the adapter having the form of a hollow
truncated cone. The smaller base of the adapter may have a diameter
adapted for connection to the connection pipe. The larger base of
the adapter is dimensioned so as to cover the whole opening of the
cooling channel in the rear face. Indeed, due to the bending of the
cooling channel and the subsequent machining of the rear face, the
cooling channel may have an elongated opening in the rear face. The
larger base of the adapter allows to ensure that a leakage at the
rear face of the cooling plate can be avoided.
[0013] Preferably, the rear face of the panel-like body, the
connection pipe and, if applicable, the adapter are connected
together through soldering or welding.
[0014] According to a first embodiment of the invention, the method
comprises the steps of providing the slab with a first cooling
channel by drilling a first blind borehole into the slab, wherein
the first blind borehole is drilled from the first edge towards the
second edge; and providing the slab with a second cooling channel
by drilling a second blind borehole into the slab, wherein the
second blind borehole is drilled from the first edge towards the
second edge. The first and second cooling channels are arranged in
such a way that their ends in a second edge region meet and form a
fluid communication between the first and second cooling
channels.
[0015] The first and second blind boreholes are both drilled from
the first edge towards the second edge at an angle with respect to
each other, in such a way that their ends meet in the second edge
region. The resulting first and second cooling channels thereby
form a combined "V"-shaped cooling channel, wherein coolant flows
through one of the cooling channels towards the second edge region
and then, through the other one of the cooling channels, back to
the first edge region. Such a "V"-shaped cooling channel allows
both the inlet connection pipe and the outlet connection pipe to be
arranged in the first edge region.
[0016] According to a second embodiment of the invention, the
method comprises the steps of providing the slab with a first
cooling channel by drilling a first blind borehole into the slab,
wherein the first blind borehole is drilled from the first edge
towards the second edge; and providing the slab with a second
cooling channel by drilling a second blind borehole into the slab,
wherein the second blind borehole is drilled from the second edge
towards the first edge. The first and second cooling channels are
arranged in such a way that their ends meet and form a fluid
communication between the first and second cooling channels.
[0017] The first and second blind boreholes are drilled from
opposite edges towards a central region of the slab, in such a way
that their ends meet in the central region. The resulting first and
second cooling channels thereby form a combined cooling channel
extending from the first edge to the second edge. This is of
particular importance when a cooling plate with particularly
important height is to be manufactured. Indeed, blind boreholes can
only be drilled up to a particular depth. If the cooling channel is
to exceed this depth, a second blind borehole is generally drilled
from the opposite side. In this embodiment, both the first edge
region and the second edge region are bent towards the rear face
before removing excess material from the slab. Two cooling channel
openings are thereby formed in the rear face without resorting to
the necessity to provide plugs at either end of the cooling
channel.
[0018] According to a third embodiment of the invention, the method
comprises the steps of providing the slab with a first cooling
channel by drilling a first blind borehole into the slab, wherein
the first blind borehole is drilled from the first edge towards the
second edge, wherein an end of the first blind borehole is arranged
in a second edge region of the slab; and, in the second edge
region, drilling a connecting bore extending from the rear face of
the slab to the end of the first blind borehole and forming a fluid
communication between the first cooling channel and the connecting
bore.
[0019] In the first edge region, the slab is bent towards the rear
face and an opening to the cooling channel is thereby formed in the
rear face. In the second edge region on the other hand, a
connecting bore is provided for forming second opening to the
cooling channel. The formation of this second opening to the
cooling channel essentially corresponds the method used in the
prior art methods. This embodiment is adapted for connecting an
inlet connection pipe in the first edge region and an outlet
connection pipe in the second edge region.
[0020] Preferably, the cooling plate is made of at least one of the
following materials: copper, a copper alloy or steel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Preferred embodiments of the invention will now be
described, by way of example, with reference to the accompanying
drawings, in which:
[0022] FIG. 1 is a schematic cross-section through a slab according
to a first step of the method for manufacturing a cooling plate in
accordance with the present invention;
[0023] FIG. 2 is a schematic cross-section through a slab according
to a second step;
[0024] FIG. 3 is a schematic cross-section through a slab according
to a third step; and
[0025] FIG. 4 is a schematic cross-section through a slab according
to a fourth step.
DETAILED DESCRIPTION
[0026] Cooling plates are used to cover the inner wall of an outer
shell of a metallurgical furnace, as e.g. a blast furnace or
electric arc furnace. The cooling plates form: (1) a heat
evacuating protection screen between the interior of the furnace
and the outer furnace shell; and (2) an anchoring means for a
refractory brick lining, a refractory guniting or a process
generated accretion layer inside the furnace.
[0027] Referring now to the Figures, it will be noted that the
cooling plate 10 is formed from a slab 11 e.g. made of a cast or
forged body of copper, a copper alloy or steel into a panel-like
body 12. This panel-like body 12, which is more closely described
by referring to FIG. 4 has a front face 14, also referred to as hot
face, which will be facing the interior of the furnace, and a rear
face 16, also referred to as cold face, which will be facing the
inner surface of the furnace wall. Referring to FIG. 4, the
panel-like body 12 generally has the form of a quadrilateral with a
pair of long edges (not shown) and a pair of short first and second
edges 22, 24. Most modern cooling plates have a width in the range
of 600 to 1300 mm and a height in the range of 1000 to 4200 mm. It
will however be understood that the height and width of the cooling
plate may be adapted, amongst others, to structural conditions of a
metallurgical furnace and to constraints resulting from their
fabrication process.
[0028] The cooling plate 10 further comprises connection pipes 26,
28 for a cooling fluid, generally water. These connection pipes 26,
28 are connected from the rear side of the panel-like body 12 to
cooling channels 30 arranged within the panel-like body 12. As seen
in FIG. 4, these cooling channels 30 extend through the panel-like
body 12 in proximity of the rear face 16. According to the proposed
method of manufacturing, which will be described in further detail
below, such cooling channels 30 are formed by drilling. Each
cooling channel 30 is normally provided with an appropriate inlet
connection pipe 26, through which the cooling fluid is fed into the
cooling channel 30, and/or outlet connection pipe 28, through which
the cooling fluid leaves the cooling channel 30.
[0029] Referring further to FIG. 4, it will be noted that the front
face 14 is subdivided by means of grooves 32 into lamellar ribs 34.
The grooves 32, laterally delimiting the lamellar ribs 34, may be
milled into the front face 14 of the panel-like body 12. The
lamellar ribs 34 extend parallel to the first and second edges 22,
24, from a first long edge (not shown) to a second long edge (not
shown) of the panel-like body 12. They are perpendicular to the
cooling channels 30 in the panel-like body 12. When the cooling
plate 10 is mounted in the furnace, the grooves 32 and lamellar
ribs 34 are arranged horizontally. They form anchorage means for
anchoring a refractory brick lining, a refractory guniting or a
process generated accretion layer to the front face 14.
[0030] In order to warrant an excellent anchoring for a refractory
brick lining, a refractory guniting material or a process formed
accretion layer to the front face 14, it should be noted that the
grooves 32 have a dovetail (or swallowtail) cross-section, i.e. the
inlet width of a groove 32 is narrower than the width at its base.
The mean width of a lamellar rib 34 is preferably smaller than the
mean width of a groove 32. Typical values for the mean width of a
groove 32 are e.g. in the range of 40 mm to 100 mm. Typical values
for the mean width of a lamellar rib 34 are e.g. in the range of 20
mm to 40 mm. The height of the lamellar ribs 34 (which corresponds
to the depth of the grooves 32) represents generally between 20%
and 40% of the total thickness of the panel-like body 12.
[0031] The method for manufacturing the cooling plates 10 will now
be more closely described by referring to FIGS. 1 to 4, which
represent the cooling plates 10 at different key steps of the
manufacturing method. In a first step, shown in FIG. 1, a slab 11
e.g. made of a cast or forged body of copper, a copper alloy or
steel is provided. Such a slab has a generally quadrilateral form
with a front face 14, rear face 16, a pair of long edges (not
shown) and a pair of short first and second edges 22, 24. It should
be noted that the slab 11 has dimensions exceeding the desired
dimensions of the panel-like body 12. At least one blind borehole
40 is drilled from the first edge 22 into the slab 11 and extends
to a second edge region 42. The blind borehole 40 has an end 44
arranged in the second edge region 42. In a subsequent step of the
method, illustrated by FIG. 2, the slab 11 is deformed in such a
way that a first edge region 46 is bent towards the rear face 16 of
the slab 11. This results in a corresponding bending of the blind
borehole 40. The bending angle a between a central axis 50 of the
unbent blind borehole 40 and a central axis 52 of the blind
borehole 40 at the first edge 22 may be between 30 and 45 degrees.
This bending angle a should however not be understood as limiting.
The bending angle a may e.g. vary considerably depending on the
thickness of the slab 11 or the diameter of the blind borehole
40.
[0032] After the slab 11 is deformed, excess material is removed
from the slab 11 along the cutting lines indicated by dotted lines
55 in FIG. 2. The resulting panel-like body 12, shown in FIG. 3, is
again of a generally quadrilateral form with a front face 14, rear
face 16, a pair of long edges (not shown) and a pair of short first
and second edges 22, 24. A cooling channel 30, formed by the blind
borehole 40, is formed in the panel-like body 12 generally parallel
to the rear face 16. In the first edge region 46, the cooling
channel 30 is bent and opens up into the rear face 16.
[0033] According to one embodiment of the present invention, the
panel-like body 12 can be provided with a bore 60 in the second
edge region 42, extending from the cooling channel 30 to the rear
face 16.
[0034] After machining excess material from the slab 11, the
resulting panel-like body 12 is further subjected to a milling
step, wherein grooves 32 and intermittent lamellar ribs 34 are
formed in the front face 14 of the panel-like body 12. As explained
above, these grooves 32 and ribs 34 form anchorage means for
anchoring a refractory brick lining, a refractory guniting or a
process generated accretion layer to the front face 14 of the
cooling plate 10.
[0035] Finally, connection pipes 26, 28 are connected to the rear
face 16 of the panel-like body 12. An inlet connection pipe 26 is
fluidly connected to the opening of the cooling channel 30 in the
first edge region 46 for feeding cooling fluid into the cooling
channel 30. An outlet connection pipe 28 is fluidly connected to
the bore 60 in the second edge region 42 for evacuating cooling
fluid from the cooling channel 30.
* * * * *