U.S. patent application number 14/926950 was filed with the patent office on 2018-04-19 for pre-cooling system having controlled internal adjustment.
The applicant listed for this patent is Cockerill Maintenance & Ingenierie S.A.. Invention is credited to Michel Dubois, Stephane Langevin.
Application Number | 20180105917 14/926950 |
Document ID | / |
Family ID | 48795435 |
Filed Date | 2018-04-19 |
United States Patent
Application |
20180105917 |
Kind Code |
A9 |
Langevin; Stephane ; et
al. |
April 19, 2018 |
Pre-Cooling System having Controlled Internal Adjustment
Abstract
The invention relates to equipment for cooling a metal strip (2)
having a liquid coating to be solidified, wherein said strip is
continuously moving. Said equipment is characterized in that each
half-cooler (11, 12) is divided, over the length thereof, into at
least two sections, a first section (13) and a second section (14),
in the direction of the movement of the strip (2). The first
section (13) is separated from the second section (14) in each
half-cooler (11, 12) by a respective internal adjustment device (7,
8), making it possible to change the gas flow/pressure parameter so
that the value of said gas flow/pressure parameter is different in
the first section (13) from the value of said parameter in the
second section (14).
Inventors: |
Langevin; Stephane;
(Ponthierry, FR) ; Dubois; Michel; (Boncelles,
BE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Cockerill Maintenance & Ingenierie S.A. |
Seraing |
|
BE |
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Prior
Publication: |
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Document Identifier |
Publication Date |
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US 20160047027 A1 |
February 18, 2016 |
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|
Family ID: |
48795435 |
Appl. No.: |
14/926950 |
Filed: |
October 29, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP2014/056523 |
Apr 1, 2014 |
|
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14926950 |
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61817113 |
Apr 29, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C23C 2/28 20130101; C21D
9/573 20130101; C23C 2/003 20130101; C21D 1/667 20130101; C23C 2/40
20130101; F27D 2009/0075 20130101; F27D 2009/0008 20130101; C21D
1/613 20130101; F27D 15/0206 20130101 |
International
Class: |
C23C 2/28 20060101
C23C002/28; C23C 2/40 20060101 C23C002/40; C23C 2/00 20060101
C23C002/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 16, 2013 |
EP |
13176682.6 |
Claims
1. Equipment for cooling a metal strip (2) having a liquid coating
to be solidified, said metal strip being continuously moving, said
equipment including a cooling box (1) provided with two gas
half-coolers (11, 12), preferably using air, each designed to cool
one face of the strip (2) and having each, on its inner face across
from the respective face of the strip, a plurality of nozzles or
slots (15) for injecting the gas at a certain flow rate, each
half-cooler (11, 12) being divided over its length into at least
two sections, a first section (13) and a second section (14),
successively arranged in the direction of the movement of the strip
(2), the first section (13) being separated from the second section
(14) in each half-cooler (11, 12), transversally relative to the
movement of the strip, by an internal regulating device (7, 8) able
to modify the flow rate/pressure parameter in the first and second
respective segments, the equipment being characterized in that the
internal regulating devices (7, 8): either are diffusers comprising
two superimposed plates each having a plurality of holes or slots
and whereof the movement of one relative to the other results in
modifying the opening section of the diffusers; or comprise a
single rotary flap or a plurality of rotary flaps; or comprise an
adjustable moving plate of the guillotine type.
2. The equipment according to claim 1, characterized in that the
internal regulating devices (7, 8) are actuated by pneumatic or
electromechanical actuators (9, 10).
3. The equipment according to claim 1, characterized in that the
half-coolers (11, 12) are connected to a shared supply circuit (3),
supplied with gas by a fan (4), which in turn is actuated by a
motor (5).
4. The equipment according to claim 3, characterized in that the
supply circuit (3) shared by the two half-coolers (11, 12) is
connected to the second section (14) of at least one of the two
half-coolers (11, 12) or to the section with a higher flow rate or
higher pressure of gas.
5. The equipment according to claim 3, characterized in that the
motor (5) is provided with a speed variator (6) making it possible
to regulate the cooling gas flow rate/pressure parameter.
6. The equipment according to claim 5, characterized in that it
comprises means for jointly or individually actuating the internal
regulating devices (7, 8) as a function of the gas flow
rate/pressure parameter regulated by the speed variator (6) and the
desired coating quality.
7. The equipment according to claim 2, characterized in that the
actuators (9, 10) of the internal regulating devices (7, 8) are
remotely controlled by a line operator.
8. The equipment according to claim 1, characterized in that the
internal regulating devices (7, 8) are duplicated, thereby creating
a third section, intermediate between the first inlet section of
the strip and the second outlet section of the strip, in order to
obtain different gas blowing speeds in the aforementioned three
sections.
9. The equipment according to claim 1, characterized in that it is
provided to move the strip in a vertical strand.
10. The equipment according to claim 1, characterized in that it
includes a pyrometer installed just after the internal regulating
devices (7, 8) in the direction of the movement of the strip, to
monitor the solidification of the coating.
11. A method for cooling a metal strip (2) moving continuously and
having a liquid coating to be solidified, using the equipment
according to claim 1, comprising a step for modifying the flow
rate/pressure parameter of gas injected by means of internal
regulating devices (7, 8) such that the value of said injected gas
flow rate/pressure parameter is different in the first section (13)
relative to its value in the second section (14).
12. The method according to claim 11, characterized in that the
injected gas flow rate/pressure parameter is modified such that the
value of said injected gas flow rate/pressure parameter is lower in
the first section (13) compared to its value in the second section
(14).
13. The method according to claim 11, characterized in that the gas
flow rate injected in the first section of the cooling equipment,
called primary flow rate, is regulated to control the solidifying
front and solidification speed of the coating still in liquid phase
at the inlet of the first section.
14. The method according to claim 11, characterized in that the
injected gas flow rate in the second section of the cooling
equipment, called secondary flow rate, is regulated to be higher
than the primary flow rate and compatible with predetermined
cooling slopes.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This patent application is a continuation of pending PCT
Application No. PCT/EP2014/056523, filed Apr. 1, 2014, which claims
priority to US Provisional Application No. 61/817,113, filed Apr.
29, 2013 and European Application No. 13176682.6 filed, Jul. 16,
2013, the entire teachings and disclosure of which are incorporated
herein by reference thereto.
SUBJECT-MATTER OF THE INVENTION
[0002] The present invention relates to a new device in the field
of pre-cooling boxes using a gaseous fluid atmosphere (air,
nitrogen, etc.), called "pre-coolers", used for example in cooling
towers for hot metal coating lines, in particular of the Aluzinc
(such as Galvalume.RTM., Al--Zn alloy, made up of 55% aluminum) and
aluminized type, but also galvanized (zinc-plated) coating.
[0003] In particular, this device applies to all cooling boxes
blowing a gas over a continuously moving metal strip and having a
liquid and unset coating having just been applied thereon.
TECHNOLOGICAL BACKGROUND AND STATE OF THE ARTS
[0004] It is known that coatings of the Aluzinc, aluminized or
other type of the same genre having just been applied on a
continuously moving metal strip must be solidified quickly to avoid
intermetallic growth and obtain a correct microstructure in order
to obtain a good corrosion resistance.
[0005] To solidify these coatings, pre-cooling units called
"pre-coolers" or cooling units called "air cooling boxes or air
coolers or ducts" are used, made using technologies and
constructions of slots, nozzles or holes.
[0006] To simplify matters, reference will be made only to
"coolers" hereafter. A series of coolers is typically installed
above equipment for applying the coating up to the first return
roller of the cooling tower.
[0007] The first cooling device(s) is (are) usually movable so as
to provide the space necessary in order to maintain that equipment
for applying the coating. These first cooler(s) generally use slot
technology.
[0008] Each cooler is generally equipped with a fan operating with
a variable speed motor, so as to be able to adjust its flow rate
and cooling air pressure based on the strips and coatings to be
treated.
[0009] If the impact of the cooling gas is too great when the
coating has not yet set, a wavy layer or marks or lines may form,
and the obtained final product may thus not comply with market
quality requirements. The sensitivity of the liquid layer to these
flaws essentially depends on the viscosity and the thickness of the
liquid layer as well as the impact of the gas.
[0010] In the context of modifying the galvanization line and
increasing production capacity, and therefore cooling, given that
the heights of the towers are difficult to alter, a same poor
quality phenomenon may be observed due to excessively intense
cooling on a coating that has not yet solidified and usually in a
certain temperature range.
[0011] Document US 2010/0200126 discloses equipment for producing,
by hot dipping, galvanized/annealed metal sheets under optimal
production conditions at any time despite rapid changes in the type
of steel, coating and other outside factors. The unit for producing
galvanized/annealed steel sheets by hot dipping is provided with a
maintaining/cooling furnace for treating metal sheets having left a
rapid heating furnace. Furthermore, the maintaining/cooling furnace
is configured to allow a change of the ratio in the furnace of the
maintaining zone to dip the steel sheet using dipping means at a
maintaining temperature of 500 to 650.degree. C. and of the cooling
zone to cool the metal sheet using spray nozzles at an average
cooling speed of 5.degree. C./second or more.
[0012] Document US 2001/0000377 discloses a method and system for
cooling a steel strip. A high water volume mist cooler and a low
water volume mist cooler are positioned successively along the
direction in which the steel strip moves. The high water volume
mist cooler vaporizes a high water volume mist on the surface of
the steel strip to cool the latter, thus cooling the steel strip
while eliminating the influence of the transitional boiling, in
order to prevent the steel strip from having a non-uniform
temperature portion.
[0013] Document US 2011/0018178 discloses a method for acting on
the temperature of a moving strip by blowing a gas or a water/gas
mixture, in which a plurality of gas or water/gas mixture jets,
extending toward the surface of the strip and arranged such that
the impacts of the gas or water/gas mixture jets on each surface of
the strip are distributed at the nodes of a two-dimensional
network, are sprayed on each face of the strip. The impacts of the
jets on one face are not across from the impacts of the jets on the
other face, and the jets of gas or water/gas mixture come from
tubular nozzles that are supplied by at least one distribution
chamber and extend at a certain distance from the distribution
chamber so as to leave a space free for the return flow of the gas
or the water/gas mixture that is parallel to the longitudinal
direction of the strip and perpendicular to the longitudinal
direction of the strip.
[0014] Document US 2011/0030820 discloses a device for blowing gas
on the face of a material in a moving strip, including at least one
hollow box whereof one wall, turned toward the relevant face of the
strip material, is equipped with a plurality of blowing orifices,
making it possible to direct gas towards the face of the strip
material. The hollow box is further laterally equipped, at least on
one side thereof in reference to a median plane perpendicular to
the plane of the strip, with a movable closing member serving to
selectively close off some of the blowing orifices in order to
adapt the width of the blowing zone to the width of the strip
material in question.
TECHNICAL PROBLEM
[0015] The problem to be resolved is as follows (see FIG. 1). The
unset coating of the strip 2 must be cooled and solidified by the
two air half-coolers 11 and 12, making up the cooler 1. The
half-coolers 11, 12 are connected to a supply circuit 3 supplied
with air by a fan 4 actuated by a motor 5.
[0016] The cooling atmosphere flow rate is regulated by a speed
variator 6 of the motor 5 of the fan 4 in order to cool the strip,
and thus its coating, more or less quickly depending on the desired
quality. It will be noted that, subsequently, the term "flow
rate/pressure parameter" will be used because the change in the fan
rating modifies both the flow rate and the pressure of the gas, the
two being related.
[0017] On the one hand, in the first part of the cooler, the speed
and the flow rate of the cooling air must be limited given that the
coating is still completely in the liquid phase, failing which a
wavy layer and/or a layer with an appearance and a microstructure
not in compliance with quality standards may be obtained.
[0018] On the other hand, on certain coating and strip thickness
formats, the cooling must be significant in order to avoid
intermetallic growth and obtain a correct microstructure.
[0019] The two preceding points are therefore sometimes
incompatible, given that the cooling air flow rate is sent more or
less uniformly, in the current technique, over the entire height of
the two air half-ducts 11, 12.
AIMS OF THE INVENTION
[0020] The present invention aims to eliminate the drawbacks of the
state of the art.
[0021] In particular, the invention aims to adjust the cooling gas
flow rate/pressure parameter, for example in the (pre-)cooling
boxes or in upper coolers situated at the outlet of units for
applying liquid coating, depending on the types of metal strips and
coatings to be handled, in order to prevent flaws from forming in
the coating.
[0022] Also in particular, the invention aims to divide a single
cooler into several sections in order to obtain several flow
rate/pressure ratings over the entire height of the cooler, and
preferably with a single fan.
MAIN FEATURES OF THE INVENTION
[0023] The present invention relates to equipment for cooling a
metal strip having a liquid coating to be solidified, said metal
strip being continuously moving, said equipment including a cooling
box provided with two gas half-coolers, preferably using air, each
designed to cool one face of the strip and having, on its inner
face across from the respective face of the strip, a plurality of
nozzles or slots for injecting the gas at a certain flow rate, each
half-cooler being divided over its length into at least two
sections, a first section and a second section, successively
arranged in the direction of the movement of the strip, the first
section being separated from the second section in each
half-cooler, transversally relative to the movement of the strip,
by an internal regulating device able to modify the flow
rate/pressure parameter in the first and second respective
segments, the equipment being characterized in that the internal
regulating devices: [0024] either are diffusers comprising two
superimposed plates each having a plurality of holes or slots and
whereof the movement of one relative to the other results in
modifying the opening section of the diffusers; [0025] or comprise
a single rotary flap or a plurality of rotary flaps; [0026] or
comprise an adjustable moving plate of the guillotine type.
[0027] According to preferred embodiments of the invention, the
equipment will be limited by one or a suitable combination of the
following features: [0028] the internal regulating devices are
actuated by pneumatic or electromechanical actuators; [0029] the
half-coolers are connected to a shared supply circuit, supplied
with gas by a fan, which in turn is actuated by a motor; [0030] the
supply circuit shared by the two half-coolers is connected to the
second section of at least one of the two half-coolers or to the
section with a higher flow rate or higher pressure of gas; [0031]
the motor is provided with a speed variator making it possible to
regulate the cooling gas flow rate/pressure parameter; [0032] the
equipment comprises means for jointly or individually actuating the
internal regulating devices as a function of the gas flow
rate/pressure parameter regulated by the speed variator and the
desired coating quality; [0033] the actuators of the internal
regulating devices are remotely controlled by a line operator;
[0034] the internal regulating devices are duplicated, thereby
creating a third section, intermediate between the first inlet
section of the strip and the second outlet section of the strip, in
order to obtain different gas blowing speeds in the aforementioned
three sections; [0035] the equipment is provided to move the strip
in a vertical strand; [0036] the equipment includes a pyrometer
installed just after the internal regulating devices in the
direction of the movement of the strip, to monitor the
solidification of the coating.
[0037] A second aspect of the present invention relates to a method
for cooling a metal strip moving continuously and having a liquid
coating to be solidified, using the aforementioned equipment,
comprising a step for modifying the flow rate/pressure parameter of
gas injected by means of internal regulating devices such that the
value of said injected gas flow rate/pressure parameter is
different in the first section relative to its value in the second
section.
[0038] Advantageously, the injected gas flow rate/pressure
parameter is modified such that the value of said injected gas flow
rate/pressure parameter is lower in the first section compared to
its value in the second section.
[0039] Still advantageously, the gas flow rate injected in the
first section of the cooling equipment, called primary flow rate,
is regulated to control the solidifying front and solidification
speed of the coating that is still in liquid phase at the inlet of
the first section.
[0040] Also advantageously, the injected gas flow rate in the
second section of the cooling equipment, called secondary flow
rate, is regulated to be higher than the primary flow rate and
compatible with predetermined cooling slopes.
BRIEF DESCRIPTION OF THE FIGURES
[0041] FIG. 1 diagrammatically shows a cooler according to the
state of the art.
[0042] FIG. 2 diagrammatically shows a cooler according to the
present invention, equipped with adjustable internal flow rate
equipment remotely controlled.
[0043] FIG. 3 shows a first embodiment of the regulating system
according to the invention, in the form of a diffuser.
[0044] FIG. 4 shows a second embodiment of the regulating system
according to the invention, in the form of a flap.
DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
[0045] The present invention provides a solution to the technical
problem set out above (see FIG. 2). According to the invention,
internal regulating systems or equipment 7, 8 are respectively
installed in the two air half-coolers 11, 12. These regulating
systems 7, 8 are intended to modify and adjust the cooling fluid
flow rate between the lower parts (inlet of the cooler) and the
upper parts (middle and outlet of the cooler) while maintaining a
uniform flow rate per unit of surface for each section. The care
taken in producing the equipment to avoid disrupting the flow of
the gas is very important in order to have homogenous and regular
cooling of the coating to be solidified.
[0046] According to one particular embodiment, these separating
systems 7, 8 may be duplicated if necessary in order to obtain
different blowing speeds between the inlet, the middle and the
outlet of the cooler, respectively.
[0047] These regulating systems 7, 8 are advantageously actuated by
pneumatic or electromechanical actuators 9, 10, with the
possibility of being remotely controlled by the line operator.
These regulating systems 7, 8 are preferably actuated jointly as a
function of the air flow rate regulated by the variator 6 of the
motor 5 of the fan 4 and the obtained coating quality.
[0048] According to preferred embodiments, these regulating systems
7, 8 can include: [0049] two superimposed plates, both having a
series of holes or slots. The movement of one of the plates
relative to the other results in decreasing the opening section and
therefore acts as a homogenous adjustable "diffuser" with respect
to the cooling air (see FIG. 3), [0050] a single rotary flap or a
series of small rotary flaps (see FIG. 4), [0051] an adjustable
moving plate of the guillotine type (not shown), etc.
ADVANTAGES OF THE DEVICE
[0052] The system according to the present invention offers the
following advantages.
[0053] The gas flow rate in the first part or section of the
cooler, called "primary" flow rate, can be regulated in order to
monitor the solidifying front and solidification speed of the
coating still in liquid phase at the inlet of the cooler, and
therefore to obtain the best possible coating quality.
[0054] The internal regulating systems or equipment for the
"primary" flow rate can be remotely controlled by the operator
depending on a cooling quality/slope criterion. The "primary"
blowing speed therefore continues to be monitored compared to a
completely manual system. A pyrometer or any other temperature
measuring system, adapted to a moving strip, can be installed just
after the regulating systems in order to monitor the cooling
slope.
[0055] The second parts or sections of the two half-coolers 11, 12
can then have a "secondary" cooling flow rate that is significantly
more substantial and compatible with the necessary cooling slopes,
or with an increase in the cooling capacity of the cooler as a
whole.
[0056] The cooling of the two half-coolers 11, 12 will therefore be
adjusted and balanced between the speed variator 6 and the
regulating systems 7, 8 delimiting the cooling inlet section. This
gives the cooler a very considerable flexibility.
[0057] The regulating systems 7, 8 also allow optimal adjustment of
the coating quality between the two faces of the strip 2, given
that they will need to have the option of being controlled
individually if necessary.
[0058] Due to the design of the system for monitoring the cooling
of the two parts, the flow rate of the cooling fluid by surface
unit is uniform in each of the sections, and in particular
transversely.
[0059] Another advantage is the flexibility of the system: it will
be very easy to move the regulating system to another position in
the (pre-)cooler if the starting position is not or ceases to be
appropriate. It is for example possible to provide three different
positions of the regulating system.
LIST OF REFERENCES
[0060] 1. Cooling box [0061] 2. Metal strip [0062] 3. Gas supply
circuit [0063] 4. Fan [0064] 5. Motor [0065] 6. Motor speed
variator [0066] 7. Internal regulating device [0067] 8. Internal
regulating device [0068] 9. Actuator [0069] 10. Actuator [0070] 11.
Half-cooler [0071] 12. Half-cooler [0072] 13. First section of the
cooler [0073] 14. Second section of the cooler [0074] 15. Gas
injection nozzles or slots
* * * * *