(DESCRIPTION]
(Technical Field]
[0001] The present invention relates to a descaling device for
removing scale or other residual foreign obj ects formed on a
surface of a hot-rolled steel strip (steel sheet), and, more
particularly, to an environmentally-friendly descaling device
for realizing the removal of scale or other residual foreign
objects on the surface of a hot-rolled steel strip (steel
sheet) through an environmentally-friendly physical
(mechanical) method excluding a typical chemical treatment and,
in addition, for highly efficiently removing scale by the
simplification of a device structure and a descaling process
as well as appropriate maintenance and adjustment of average
surface roughness of the steel strip after descaling.
(Background Art]
[0002] A scale layer about 5 llm to 15 llm thick is commonly
formed on a surface of a hot-rolled steel sheet (steel strip),
e.g., a hot-rolled carbon steel sheet, a high strength steel
sheet, a silicon added steel sheet for an electric motor, or a
stainless steel sheet.
[0003] For example, FIG. 1 illustrates a well known facility
for removing the scale formed on the surface of a hot-rolled
steel sheet.
2
[0004] That is, as illustrated in FIG. 1, the generally known
typical pickling facility for descaling removes scale while a
steel sheet stepwisely passes through a pickling tank 240 and
a washing tank 250, after cracks are formed in the scale by
using a scale breaker 230.
[0005] The pickling tank 240 is typically composed of four
unit pickling tanks 242, 244, 246, and 248, and the picking
tank mainly uses a high-temperature strong acid, such as
hydrochloric acid or sulfuric acid, to chemically remove scale
from the surface of the hot-rolled steel sheet passing
therethrough.
[0006] At this time, undescribed reference numerals in FIG. 1,
210, 220, and 260 respectively denote a pay-off reel, a welder,
and a tension reel, and, although not specifically illustrated,
the washing tank 250 may be divided as brushing and rinsing
operations.
[0007] However, with respect to the foregoing typical scale
treatment method illustrated in FIG. 1, there are various
limitations, such as an increase in the length of the facility
due to the use of a plurality of pickling tanks and washing
tanks, obstruction of working environments due to the
generation of acid vapors, the generation of environmentally
hazardous waste products due to waste acid treatment, an
increase in required supplementary facilities due to acid
recovery and the need for acid resistant equipment,
differences in descaling performances according to steels, and
3
the occurrence of quality failures in the case of steel sheets
remaining in acid solution tanks and washing tanks in the case
that the production line stops.
[0008] For example, although schematically illustrated in FIG.
1, since the lengths of the actual pickling tank 240 and the
washing tank 250 are about 100 meters in a method of removing
scale through the foregoing typical pickling treatment, the
surface qualities of hot-rolled steel sheets remaining in the
pickling tank and the washing tank may be deteriorated due to
an excessive acid treatment in the case that the production
line stops.
[0009] Meanwhile, as an another method of removing scale for
addressing the limitations of the typical method of removing
scale by the medium of chemical pickling by using the
foregoing acid solution illustrated in FIG. 1, a technique of
removing scale from a surface of a steel sheet by using a
physical method has been developed, in which metal shot balls
or grit particles are in contact with the surface of the steel
sheet or a slurry having metal shot balls or grit, particles
mixed with water is in contact with the surface of the steel
sheet by using a centrifugal force.
[0010] However, the physical descaling method using shot balls
or grit particles is performed in parallel with a known
pickling process, in which the physical descaling method using
shot balls or grit particles is mainly used as a pretreatment
process for pickling to increase pickling efficiency in
4
special steels, such as stainless steel sheets or electrical
steel sheets, steels traditionally difficult to be pickled.
For example, the physical descaling process using shot balls
or grit particles is not applied to general carbon steels.
[0011] Meanwhile, another physical method for removing scale
has been developed, in which a slurry having stainless steel
(STS) beads mixed with water, instead of typical shot balls or
grit particles, is in contact with a surface of a steel sheet
through centrifugal force.
[0012] However, with respect to descaling methods, in which
metal shot balls or grit particles are in contact with the
surface of the steel sheet or a slurry having stainless steel
beads mixed with water is in contact with the surface of the
steel sheet through centrifugal force, since an average
surface roughness (Ra) of the steel sheet after descaling is
in a range of 2.3 ~m to 3.5 ~m due to a phenomenon of
embedding in the steel sheet, the surface roughness of the
descaled steel sheet may be entirely non-uniform. In addition,
a unit price of the stainless steel beads may be high.
[0013] Meanwhile, other descaling techniques, such as a method
of removing scale through the injection of high-pressure water
or a method of injecting ice particles, have been developed,
but descaling efficiencies thereof may be insignificant, and
the commercialization thereof may be difficult.
[Disclosure]
5
(Technical Problem)
[0014] An aspect of the present invention provides a descaling
device providing a highly efficient descaling environment
suitable for high-speed strip-passing as well as being more
environmentally friendly by uniformizing average surface
roughness of a steel strip (steel sheet) after descaling,
while realizing a physical (mechanical) method of removing
scale or other foreign objects without a typical chemical
treatment.
[0015] Another aspect of the present invention provides a
descaling device able to simplify processing or a processing
facility by effective descaling as well as simplification of a
device structure being achieved by the introduction of an
abrasive to the device through the formation of negative
pressure.
(Technical Solution)
[0016] According to an aspect of the present invention, there
is provided a descaling device including: a device housing
disposed in a feed path of a hot-rolled steel strip; a highpressure
fluid supply unit provided to supply a high-pressure
fluid to the device housing; an abrasive input unit provided
to introduce an abrasive into the device housing; and an
abrasive slurry spraying unit provided in the device housing
to spray an abrasive slurry having the high-pressure fluid and
the abrasive mixed inside the device housing onto the steel
6
strip.
[0017] The high-pressure fluid supply unit provided in the
device housing may provide the high-pressure fluid by
inj ecting the high-pressure fluid inside the device housing,
and may be configured to smoothly introduce the abrasive into
the inside of the device housing by using inj ection pressure
of the high-pressure fluid.
[0018] The abrasive may have a specific gravity lower than
that of metal.
[0019] At this time, the abrasive may be formed of one of
silicon oxide, silicon carbide, aluminum oxide, glass, or a
ceramic having a particle diameter ranging from 10 ~m to 400
~m.
[0020] The device housing may include a first connecting
portion connected to the high-pressure fluid supply unit; a
second connecting portion connected to the abrasive input
unit; and a spraying unit assembly portion having the abrasive
slurry spraying unit assembled therein.
[0021] The high-pressure fluid supply unit may include a highpressure
fluid inlet provided inside the first connecting
portion included in the device housing and having the highpressure
fluid supplied thereto; and a high-pressure fluid
nozzle provided to the high-pressure fluid inlet and having a
nozzle hole formed therein to inject the high-pressure fluid
into the inside of the device housing.
[0022] At this time, a position of a horizontal line at a
7
lower end of the high-pressure fluid nozzle may be adjusted to
meet with a center point of an outlet of the inclined second
connecting portion included in the device housing.
[0023] In addition, the high-pressure fluid may be formed of
high-pressure water inj ected through the high-pressure fluid
nozzle in a pressure range of 100 bar to 500 bar, and spacing
between the abrasive slurry spraying unit included in the
device housing and the steel strip may be in a range of 100 ffiffi
to 350 ffiffi.
[0024] The abrasive input unit may include an abrasive input
hose connected to the second connecting portion included in
the device housing, and a negative pressure space allowing the
abrasive to be introduced into the device housing through
suction by the medium of injection pressure of the highpressure
fluid may be formed inside the device housing.
[0025] The abrasive slurry spraying unit may include a
spraying unit body provided in the spraying unit assembly
portion included in the device housing; a depressed portion
formed in an upper portion of the spraying unit body; and an
abrasive slurry spray opening formed by penetrating through
the body from the depressed portion.
[0026] The depressed portion in the spraying unit body is
concavely formed to have a conical shape from an upper end of
the spraying unit body to an inner side thereof, and the spray
opening is formed as a slit formed by integrally penetrating
from a center of the conical depression portion to a lower end
8
of the body.
[0027] At this time, a cut portion having a predetermined
angle through the spray opening may be further formed at both
sides of the lower end of the spraying unit body.
[0028] The descaling device may further include a mixing unit
provided in the device housing to allow the high-pressure
fluid and the abrasive to be smoothly mixed therein.
[0029] The mixing unit may be provided as a fixed-type mixing
unit formed of one of one or more grid units provided between
the high-pressure fluid supply unit and the abrasive slurry
spraying unit and one or more conical coils provided between
the grid units or independently provided in the device housing,
or provided as a combination thereof.
[0030] The mixing unit may be provided as a rotary type mixing
unit included in a rotational axis provided between the highpressure
fluid supply unit and the spraying unit in the device
housing and may include rotors or rotation bars rotated by
collision of the high-pressure fluid.
[Advantageous Effects]
[0031] According to a descaling device of the present
invention, since scale of a hot-rolled strip (steel sheet) may
be continuously removed and, in particular, descaling
efficiency may be secured even in the case that a high-speed
treatment as well as the size of facility being reducible,
cost reduction may be possible as well as productivity being
9
improved.
[0032] In particular, a more environmentally-friendly
operations may be possible in a facility by removing
environmental hazards due to the generation of acid vapors,
acid recovery, and a waste acid treatment generated during a
typical pickling treatment.
[0033] Also, since the surface quality of the steel sheet may
be ultimately improved by removing non-uniformity of the
surface roughness according to the use of typical metal shot
balls, grit particles, or beads, an improvement of quality may
be possible in a subsequent process, such as plating of the
steel sheet.
[0034] In particular, the present invention is suitable for
removing scale from the surface of a hot-rolled steel strip,
such as hot-rolled low carbon steel sheets, ultra-low carbon
steel sheets, high-strength carbon steel sheets, high carbon
steel sheets, electrical steel sheets, or stainless steel
sheets.
[Description of Drawings]
[0035] The above and other aspects, features and other
advantages of the present invention will be more clearly
understood from the following detailed description taken in
conjunction with the accompanying drawings, in which:
[0036] FIG. 1 is a schematic view illustrating a typical
process of removing scale through chemical pickling;
10
[0037] FIG. 2 is a schematic view illustrating a process of
treating a surface of a hot-rolled steel sheet including a
descaling device according to the present invention;
[0038] FIG. 3 is an entire schematic view illustrating the
descaling device according to the present invention;
[0039] FIG. 4 is an exploded view illustrating the descaling
device according to the present invention in FIG. 3;
[0040] FIG. 5 is an entire schematic view illustrating
surrounding facility linked to the descaling device according
to the present invention; and
[0041] FIGS. 6 through 8 are schematic views illustrating
various embodiments of a mixing device included in the
descaling device according to the present invention.
[Best Mode)
[0042] Hereinafter, the present invention will be described in
detail with reference to the accompanying drawings.
[0043] FIGS. 2 to 5 illustrate a descaling device 1 according
to the present invention and a use state thereof in the
process thereof.
[0044] That is, as illustrated in FIG. 2, a hot-rolled coil
primarily passes through a scale breaker 150 previously
described while being unwound and wound at a high speed
between a payoff reel 130 and a tension reel 180, and scale
is removed while being passed through a chamber 120, in which
the descaling devices 1 of the present invention are
11
appropriately arranged at upper and lower sides of a moving
steel strip 2 (hereinafter, referred to as "steel sheet"), by
the medium of feed rolls 122.
[0045] Thereafter, the steel sheet passes through a washing
tank 160 composed of a brushing tank 162 and a rinsing tank
164, and a drying tank (hot air tank) 170.
[0046] Therefore, when compared with FIG. 1, it may be
understood that a facility size of a typical pickling tank 240
is significantly reduced in the case that the descaling device
1 of the present invention is used. Even in the simplified
facility, the descaling device 1 of the present invention may
provide sufficient descaling in a state in which the steel
sheet 2 moves at a high speed, and in particular, may
uniformize an average surface roughness Ra of the surface of
the steel sheet (steel strip) after descaling in a range of 1
].lm to 1.5 ].lm.
[0047] That is, since the descaling device 1 of the present
invention may secure descaling efficiency and may also control
the surface roughness of the steel sheet as well as the
appropriate surface roughness thereof after descaling being
provided, the descaling device 1 of the present invention may
easily cope with processing characteristics required by
customers or various conditions of the surface roughness
required during subsequent processes, such as cold rolling and
plating.
[0048] At this time, an undescribed reference numeral in FIG.
12
2, 140, denotes a welder for welding lead and tailing steel
sheets unwound from the payoff reel 130 for continuous
processing.
[0049] FIGS. 3 to 5 illustrate the descaling device 1 of the
present invention in more detail. In the drawing, a magnified
view of an abrasive 6 is illustrated. Also, high-pressure
water 4 is described as an example of a high-pressure fluid
below.
[0050] That is, as illustrated in FIGS. 3 and 4, the descaling
device 1 of the present invention may broadly include one or
more device housings 10 disposed in a feed path of the moving
hot-rolled steel sheet 2 (at a high speed) and a high-pressure
water supply unit 30 included in the device housing 10 so as
to supply the high-pressure water 4 to the device housing 10.
[0051] In particular, the device of the present invention does
not simply provide the high-pressure water inside the single
device housing 10, but employs a double injection method
injecting the high-pressure water from the inside thereof. As
described in detail below, the reason for the internal
injection is that the abrasive may not only be smoothly
introduced into the device housing by using injection pressure
of the high-pressure water injected inside the device without
the application of external pressure, but the abrasive, Le.
glass beads or ceramic beads, may also be smoothly mixed with
the water (high-pressure water) .
[0052] That is, the device of the present invention may
13
further include an abrasive input unit 50 able to introduce
the abrasive 6 into the device housing 10 through smooth
suction by the medium of injection pressure of the highpressure
water 4 without the application of external pressure
and an abrasive slurry spraying unit 70 included in the device
housing to spray an abrasive slurry 8 having the high-pressure
water 4 and the abrasive 6 mixed inside of the device housing
on the steel sheet by using a direct spray method.
[0053] Therefore, in the present invention, when the highpressure
water 4 is inj ected from the inside of the device
housing 10 into the device housing 10, a negative pressure
space T may be formed inside the device housing as illustrated
in FIG. 3, and, as a result, the abrasive 6 may be smoothly
introduced through suction without the application of external
pressure.
[0054] Next, the high-pressure water 4 and the abrasive 6 may
be mixed inside the device housing 10 of the present invention
to be sprayed into the surf~ce of the steel sheet 2 moving in
the chamber 120 through the abrasive slurry spraying unit 70
as illustrated in FIG. 5, and thus, an effect of removing
scale (see 2' in FIGS. 3 and 5) on the surface of the steel
sheet may be maximized.
[0055] Eventually, when the descaling device 1 of the present
invention, as illustrated in FIGS. 3 and 5, simply introduces
the abrasive 6 into the device housing 10 without the separate
application of external pressure, the abrasive 6- may be
14
relatively uniformly sucked into the device housing by the
formation of the internal negative pressure space T due to the
high-pressure water 4. Since external pressure facility may
not be required, the structure of the device may be simplified.
[0056] At this time, with respect to the abrasive 6 of the
present invention required for preparing the abrasive slurry 8
able to remove scale or other residual foreign obj ects by
being in contact with the surface of the steel sheet while
being mixed with the high-pressure water, an abrasive having a
specific gravity lower than that of metal may be used. For
example, silicon oxide, silicon carbide, aluminum oxide, glass,
or ceramic may be used.
[0057] For example, glass or ceramic beads having a uniform
diameter may be used as an abrasive, and the glass or ceramic
beads in a powder form (since the diameter thereof is actually
relatively small, the beads look like a powder) may only be
introduced into the device housing or a slurry (solution state
having viscosity) having the glass or ceramic beads mixed with
water in advance may be provided.
[0058] Although magnified in FIGS. 3 and 5, a diameter of the
abrasive 6 provided as the glass beads or ceramic beads may be
in a range of 10 pm to 400 pm, and for example, may be in a
range of 80 pm to 200 pm.
[0059] At this time, in the case that the diameter of the
abrasive is 10 pm or less, the effect of removing the scale 2'
from the surface of the steel sheet may be insignificant due
15
to excessively small diameter thereof. In contrast, in the
case in which the diameter of the abrasive is 400 pm or more,
the efficiency of removing the scale may be improved, but a
deviation in the surface roughness of the steel sheet 2 after
descaling may be high. Therefore, surface quality of the steel
sheet may not be secured and a subsequent process, such as a
separate milling process, may be required.
[0060] Meanwhile, typical abrasives, such as metal shot balls,
grit particles, or stainless steel beads, and glass beads of
the present invention are compared and listed in the following
Table 1.
[0061] [Table 1]
Category
Remarks
Al203 I Steel I SiC
(Grit) (Grit) (Grit)
With respect to a slurry
having typical grit
particles mixed with
water, a deviation in
the surface roughness of
steel sheet is high due
to the occurrence of a
phenomenon of embedding
in a material and an
average diameter thereof
is in a range of 141 ~m
to 147 ~m, and since a
wet process is used,
reprocessing may be
difficult.
STS (bead)
Since unit
price of a
typical
stainless steel
bead is
expensive and a
diameter
thereof is
small at about
60 ~m, the
efficiency of
removing scale
may be low.
Glass
(bead)
A diameter of the
glass bead of the
present invention is
about 117 ~m, and
since the efficiency
of removing scale is
appropriate, costs
are low, reprocessing
is facilitated, and
in particular, the
phenomenon of
embedding in a.
material is absent,
the deviation in the
surface roughness may
be low.
[0062] Therefore, as illustrated in Table 1, the abrasive of
the present invention may be selected from glass or ceramic
having a specific gravity lower than that of metal, which may
also control the average surface roughness of the steel sheet
as well as the appropriate average surface roughness thereof
16
after descaling being provided, but the glass or ceramic may
be allowed to have a bead shape. That is, the present
invention may remove limitations generated during the use of
typical shot balls, grit particles, and stainless steel beads.
[0063] Next, an appropriate inj ection pressure of the highpressure
water 4 of the present invention may be in a range of
100 bar to 500 bar based on the abrasive 6, the foregoing
glass beads having a diameter ranging from 10 pm to 400 pm, in
order to appropriately form negative pressure (space) to
smoothly suck the abrasive 6, such as glass beads, into the
device housing 10 and also stably maintain the removal of
scale from the surface of the steel sheet.
[0064] At this time, in the case that the pressure of the
high-pressure water is 100 bar or less, spray pressure of the
abrasive slurry finally sprayed from the device may be low,
and thus, the efficiency of removing scale from the surface of
the steel sheet may be insignificant. In contrast, in the case
that the pressure thereof is 500 bar or more, since the
collision pressure of the abrasive on the surface of the steel
sheet may be excessively high, the deviation of the surface
roughness Ra of the steel sheet may be relatively high, and
equipment operating costs, such as electricity costs due to
the overloading of equipment during the operating thereof, may
increase.
[0065] Next, the descaling device 1 of the present invention
satisfying the foregoing conditions of the pressure of high-
17
pressure water and the abrasive will be described in detail.
First, as illustrated in FIGS. 3 and 4, the device housing 10
in the device of the present invention may include a first
connecting portion 12 connected to the high-pressure water
supply unit 30 to be later described in detail, a second
connecting portion 14 connected to the abrasive input unit 50,
and a spraying unit assembly portion 16 having the abrasive
slurry spraying unit 70 assembled therein.
[0066] The device housing 10 of the present invention, for
example, may be divided and assembled for internal assembly by
being manufactured in a cast form, and the first connecting
portion 12 at an upper side thereof and the second connecting
portion 14 in an inclined state at a center portion thereof
are formed in a single piece.
[0067] Also, an opening 18 having a chamfered shape is formed
in a lower end portion of the device housing 10 of the present
invention, in order to allow the abrasive slurry 8 to be
spread during spraying.
[0068] Although not specifically illustrated in a separate
drawing, a plurality of the device housings 10 of the present
invention may be actually arranged in an appropriate spacing
in an equipment head unit (not shown). In particular, a
hydraulic cylinder may be connected to the head unit to adjust
a spacing between the steel sheet and a lower end of the
device housing and, as shown in FIG. 3, the tilt of the device
housing 10 may also be adjusted through driving gears or the
18
like to be obliquely arranged toward the moving steel sheet
within 45 degrees.
[0069] For example, as illustrated in FIGS. 3 and 5, the head
unit connected to the device housing 10 of the unit descaling
device of the present invention is required to adjust a spray
width of the abrasive slurry according to the width of the
moving hot-rolled steel sheet 2 and in particular, the
abrasive slurry 8 sprayed on the steel sheet may also be
sprayed on upper and lower portions of the hot-rolled steel
sheet 2 in the same spray pattern.
[0070] In particular, both end portions (interface portion) of
an abrasive slurry stream sprayed from the unit device may be
controlled to have an overlapping pattern.
[0071] Also, the spray pressure or spray angle of the abrasive
slurry and the spacing between the lower end of the device and
the steel sheet may be adjusted in consideration of a
thickness of scale generated according to a moving speed of
the steel sheet or a thickness of the steel sheet.
[0072] For example, as illustrated in FIGS. 3 and 5, spacing
between an outlet of the spraying unit 70 at the lower end of
the device hosing 10 of the present invention and the steel
sheet 2 may be adjusted in a range of 100 rom to 350 rom. The
spacing between the outlet of the spraying unit and the steel
sheet may directly affect descaling performance or a descaling
width, and, for example, in the case that the spacing is 100
rom or less, the descaling width may be relatively narrow, and
19
thus, the number of the device housing installed may be
unnecessarily increased. In contrast, in the case in which the
spacing is 350 rom or more, the descaling performance may be
insignificant.
[0073] Also, the second connecting portion 14 connected to the
abrasive input unit 50 of the device housing 10 may also be
obliquely formed toward the device housing 10. For example,
the second connecting portion 14 may be inclined at an angle
of about 45 degrees, when considering the fact that the
abrasive 6 is fine beads having a diameter in microns and
inj ected into the device housing without the application of
external pressure.
[0074] Next, as illustrated in FIGS. 3 and 5, the highpressure
water supply unit 30 of the descaling device 1 of the
present invention is provided inside the device housing while
being provided in the first connecting portion 12 of the
device housing 10, and may include a high-pressure water
supply inlet 32 connected to a high-pressure water supply tube
40 and a high-pressure water nozzle 36 provided in the highpressure
water supply inlet 32 and having a nozzle hole 34
formed therein.
[0075] That is, as illustrated in FIGS. 3 and 4, the highpressure
water supply inlet 32 passes through a locking cap 38
provided in an upper portion of the first connecting portion
12 of the device housing 10 to be supported by stopping at a
stopper protrusion at an upper end thereof, and a screw
20
portion S formed on an outer circumference of the highpressure
supply inlet 32 are assembled by being fastened to a
screw portion S formed on an inner circumference of the first
connecting portion 12 of the device housing 10.
[0076] A high-pressure supply hose 40 is connected to the
locking cap 38 to supply the high-pressure water 4 thereto and
the supplied high-pressure water is provided through an
internal hole of the supply inlet 32.
[0077] At the same time, as illustrated in FIG. 4, a screw
portion S formed on an outer circumference of an upper portion
of the high-pressure water nozzle 36 may be simply provided in
a screw portion S formed on an inner circumference of a spray
nozzle assembly portion 32a at a lower end of the highpressure
water supply inlet 32.
[0078] Therefore, the supplied high-pressure water is injected
into the device housing 10 through the nozzle hole 34 formed
through the center of the high-pressure water nozzle 36.
[0079] At this time, as illustrated in FIGS. 3 and 4, the
nozzle hole 34 formed in the high-pressure water nozzle 36 may
be formed in an elliptical shape so as to allow the highpressure
water to be inj ected in a spreading form into the
device housing 10.
[0080] In particular, as illustrated in FIG. 3, the highpressure
water 4 injected in a spreading form may be injected
in a thin and wide shape corresponding to a slit-form spray
opening 76 formed in a body 72 of the abrasive slurry spraying
21
unit 70 to be later described in detail.
[0081] That is, in the device of the present invention, the
nozzle hole 34 included in the high-pressure water nozzle 36,
for example, may be formed in an elliptical shape elongated in
a direction corresponding to the slit-form spray opening 76 of
the abrasive slurry spraying unit 70.
[0082] Next, as illustrated in FIGS. 3 to 5, the abrasive
input unit 50 in the descaling device 1 of the present
invention includes an abrasive input hose 52 connected to the
second connecting portion 14 obliquely formed in the center
portion of the device housing 10.
[0083] A thick hose is used for the abrasive input hose 52 so
as to maintain stiffness and an abrasive, i.e., the glass or
ceramic bead abrasive 6, may be supplied through a line 12 by
being linked to an abrasive supply hopper 54 to later be
described in FIG. 5.
[0084] Therefore, in the device of the present invention as
illustrated in FIG. 3, since the high-pressure water nozzle 36
of the high-pressure supply unit 30 injects the high-pressure
water at an appropriate pressure while being provided in the
lower portion of the high-pressure water supply inlet 32
elongated and entered into the device housing 10 and the
device housing 10 is closed, the negative pressure space T
having pressure rapidly decreased may be formed in a lower
portion of the high-pressure water injection nozzle 36.
[0085] Eventually, at the moment of introducing the abrasive
22
•
to the device housing through an inner outlet (see C" in FIG.
6) of the second connecting portion 14 of the device housing
connected to the abrasive supply hose 52 disposed near the
high-pressure water injection nozzle 36, the abrasive is
smoothly introduced to the negative pressure space without the
application of external pressure, and the high-pressure water
4 and the abrasive 6 are mixed to form the abrasive slurry 8
finally sprayed on the surface of the steel sheet.
[0086] That is, since the present invention provides a
configuration in which the abrasive is sucked into the device
housing through the formation of negative pressure in the
device housing without using a separate external pressure
apparatus, an overall structure of the device may be
simplified, and, as a result, cost reduction through the
simplification of the structure of the device may be possible
and in particular, an increase in operation costs of the
device according to the application of external pressure may
be prevented.
[0087] Meanwhile, as illustrated in FIGS. 3 and 6, a
horizontal line C' at a lower end of the high-pressure water
nozzle 36 of the high-pressure water supply unit 30 in the
device according to the present invention may be allowed to
meet with an inner center P (center of an inner center line C
of the second connecting portion in FIG. 6) of the second
connecting portion 14 of the device housing 10 for the input
of the abrasive.
23
[0088] In this case, the mixing of the injected high-pressure
water 4 and the inputted abrasive 6 may be uniformly realized.
[0089] For example, appropriate arrangements of the highpressure
water injection nozzle of the high-pressure supply
unit and the abrasive input space through the second
connecting portion are presented in the following Table 2.
[0090] [Table 2]
Comparative
Example 1
10
Defective
treatment of
scale
In the case that
the lower end of
the device
housing is formed
as a simple
opening, the
formation of a
negative pressure
space is
insufficient, and
thus, the input
of the abrasive
into the device
may not be
smoothly
performed
Comparative
Example 2
10
Defective
treatment of scale
In the case that a
simple nozzle hole
is formed in the
device housing,
normal descaling
may be difficult
due to the nonuniform
suction of
the abrasive
Comparative
Example 3
10
Incomplete
treatment of
scale
The spacing
between the highpressure
water
supply unit 30
and the abrasive
slurry spraying
unit 70 is
excessively
narrow and thus,
the abrasive and
the high-pressure
water are sprayed
before they are
sufficiently and
uniformly mixed
into an abrasive
slurry
Present
invention
Good treatment
of scale
Realizing the
best descaling
due to an
appropriate
spacing between
the highpressure
water
supply unit and
the abrasive
slurry spraying
unit
[0091] Therefore, as illustrated in Table 2, it may be
understood that the position of the horizontal line at the
lower end of the injection nozzle of the high-pressure water
supply unit 30, for example, may be controlled to be at the
24
•
center of the inner center line of the second connecting
portion 14 and an outlet of the connecting portion in view of
the descaling efficiency.
[0092] Meanwhile, as illustrated in FIG.3, a mixing space MX
having the high-pressure water 4 injected into a lower side of
the negative pressure space T and the inputted abrasive 6,
such as glass beads, mixed therein may be further formed in
the device housing of the descaling device 1 of the present
invention
[0093] Mixing units described in detail in the following FIGS.
6 to 8 may be disposed in the mixing space MX of the present
invention.
[0094] For example, mixability of the high-pressure water and
the abrasive in the device of the present invention is
important, and the reason for this is that only when the highpressure
water and the abrasive are uniformly mixed, the
abrasive slurry 8 having the high-pressure water and the
abrasive uniformly mixed therein is sprayed on the surface of
the steel sheet and accordingly, the descaling efficiency may
not only increase, but the deviation of the average surface
roughness of the steel sheet after descaling may also be small.
The mixing units will be described in detail in the following
FIGS. 6 to 8.
[0095] Next, FIGS. 3 to 5 illustrate the abrasive slurry
spraying unit 70 able to actually remove scale while the
abrasive slurry 8 is appropriately sprayed from the descaling
25
device 1 and accordingly, the average surface roughness of the
steel sheet is controlled to be in an appropriate range.
[0096] That is, the abrasive slurry spraying unit 70 of the
present invention may include the spraying unit body 72, a
cylindrical body formed in a lower end portion of the device
housing 10 in a lower side of the negative pressure space T in
the device housing and provided in the spraying unit assembly
portion 16 including a concavely formed cut portion 18, a
depressed portion 74 allowing the abrasive slurry to be
sprayed in a more uniform state by inducing laminar flow of
the abrasive slurry 8 in an upper side of the spraying unit
body, and an abrasive slurry spray opening 76 provided to
allow the abrasive slurry to be sprayed on the steel sheet by
vertically penetrating through the spraying unit body from the
depressed portion.
[0097] At this time, as illustrated in FIGS. 3 and 4, the
depressed portion 74 may be formed as a conical depression
portion concavely recessed into an upper portion of the
spraying unit body 72.
[0098] Also, as illustrated in FIG.4, a fixing ring 82
inserted and provided in a fixing groove 20 formed in a side
of the spraying unit assembly portion 16 of the device housing
10 is provided in an outer circumference of the cylindrical
body 72 of the spraying unit, and a fixing hole 80 having a
lock pin 22 fastened in the form of a screw from the outside
of the device housing fixed therethrough is formed on the
26
outer circumference thereof.
[0099] Therefore, in the device according to the present
invention, the cylindrical body 72 of the abrasive slurry
spraying unit 70 may be firmly assembled and fixed into the
spraying unit assembly portion 16 of the device housing.
[00100] At the same time, in the abrasive slurry spraying
unit 70 of the present invention, the abrasive slurry spray
opening 76 may be provided in the form of a slit integrally
penetrating from a center portion of the conical depression
portion 74 to a lower end of the body.
[00101] Therefore, as illustrated in FIGS. 3 to 5, since
the high-pressure water 4 inj ected from the inside of the
device housing forms the negative pressure space T to generate
suction of the abrasive without the application of external
pressure, and the abrasive 6 formed of glass beads introduced
at this time is uniformly mixed in the mixing space MX at the
lower side of the high-pressure water nozzle 36 of the highpressure
water supply unit, and is then induced in the form of
laminar flow toward the center of the conical depression
portion 74 concavely formed in the upper portion of the body
of the spraying unit 70 and sprayed through the slit-form
spray opening 76 at the center thereof, the abrasive slurry 8
finally sprayed on the surface of the steel sheet may be more
uniformly sprayed in comparison to the case of simply
including a nozzle opening in Table 2.
[00102] In particular, since an abrasive slurry stream
27
+
sprayed through the concave conical depression portion 74 of
the spraying unit 70 and the slit-form spray opening 76, as
illustrated in FIG. 3, is sprayed in the shape having
predetermined thickness and width, scale from the surface of
the steel sheet may be further intensively removed.
[00103] Therefore, an inlet of the spray opening 76 is
provided in a "V" shape due to the conical depression portion
74 and an outlet thereof, although not illustrated using a
separate reference numeral, is provided as a rectangular flat
opening.
[00104] At this time, as illustrated in FIGS. 3 and 4, the
cut portion 78 having a predetermined angle (e in FIG. 4)
through the spray opening may be further formed at both sides
of the spraying unit body on both sides of the lower end
portion of the slit-form spray opening 76 formed by
penetrating through the center of the body 72 of the spraying
unit 70.
[00105] Therefore, the cut portion 78 may allow the sprayed
abrasive slurry stream to be appropriately spread in the lower
end portion of the spraying unit and thus, may more uniformly
and smoothly remove scale on the steel sheet.
[00106] At this time, the cut portion 78 connected through
the outlet of the spray opening 76 at both sides of the lower
end portion of the body of the spraying unit may be formed to
have an angle ranging from 15 degrees to 30 degrees, and in
this case, a contact area of the surface of the steel sheet by
28
the appropriately sprayed abrasive slurry 8 may be
appropriately increased.
[00107] Eventually, since the abrasive slurry spraying unit
70 of the present invention allows the high-pressure water 4
and the abrasive 6 in a mixed state to be induced toward the
center of the concave depressed portion 74 and to be sprayed
through the slit-form spray opening 76, the descaling
efficiency may be high, and thus, uniform mixing between the
water and the abrasive may be obtained as well as sufficient
descaling performance being secured even in the case that a
line speed of the steel sheet is increased. Therefore, the
average surface roughness of the steel sheet after descaling
may be maintained in a range of 1 J.UTl to 1.5 J.UTl through the
uniform distribution of the abrasive actually being in contact
with the surface of the steel sheet during descaling.
[00108] That is, since the deviation of the surface
roughness is low, scale may be uniformly removed from the
entire surface of the steel sheet, and thus, surface quality
of the steel sheet may be excellently maintained.
[00109] Next, as described above, FIGS. 6 to 8 illustrate
various types of the mixing units for the high-pressure water
and the abrasive installed in the mixing space MX of the
present invention in FIG. 3 to allow the water and the
abrasive to be smoothly mixed therein.
[00110] That is, as illustrated in FIGS. 6 to 8, the mixing
units of the present invention may be specifically classified
29
as a position fixed-type mixing unit and a rotary type mixing
unit 110.
[00111] For example, the position fixed-type mixing units
are illustrated in FIGS. 6 and 7, and may be provided as one
or more grid units 90 installed in the mixing space MX at a
center side of the lower portion of the negative pressure
space T of the device housing 10 in a lower side of the highpressure
water supply unit 30 in the device housing 10 as
illustrated in FIG. 6 or a conical coil 100 provided between
the grid units or independently provided as illustrated in FIG.
7.
[00112] At this time, as illustrated in FIGS. 3 and 6, the
grid units 90 of the present invention, for example, may be
provided as upper and lower sides, first and second grid units
90a and 90b.
[00113] That is, as illustrated in FIGS. 4 and 6, the grid
units 90 has a configuration in which abrasive slurry
collision bars 94 and 94' arranged in a mutually perpendicular
direction according to the positions of upper and lower
portions are fixed into the inside of fixing rings 92 provided
in fixing grooves (no reference numeral) formed in an inner
side of the lower end portion of the device housing 10.
[00114] Therefore, mixing of the high-pressure water
(water) and the abrasive may be smoothly performed while the
abrasive slurry 8 having the high-pressure water and the
abrasive mixed therein passes through the upper and lower
30
sides, first and second grid units, i. e., the collision bars
94 and 94' having an opposite direction, from top to bottom.
[00115] For example, since the collision bars of the first
and second grid units are orthogonally arranged, mixing of the
water and the abrasive may be more smoothly performed while
the collision bars rotate in a different direction from each
other, in the case that the abrasive slurry 8 collides with
the actual bars.
[00116] Next, as illustrated in FIG. 7, other types of the
position fix mixing units may be provided as a conical coil
(coil spring) 100 disposed in the mixing space MX inside the
device housing illustrated in FIG.3.
[00117] Since an upper end or a lower end of the conical
coil 100, a position fixed-type mixing unit, has a small
diameter and the coil diameter increases toward an opposite
side thereof, mixing of the high-pressure water and the
abrasive may be more uniformly performed when the abrasive
slurry 8 having the high-pressure water and the abrasive mixed
therein passes through the conical coil.
[00118] Meanwhile, the conical coLl 100, a position fixedtype
mixing unit, is disposed between the first and second
grid units 90a and 90b previously described or disposed in a
lower portion of the upper side first grid unit, and is
possible to have a configuration in which a lower end portion
of the conical coil is stably placed on the conical depression
portion 74 formed in an upper portion of the cylindrical body
31
72 of the abrasive slurry spraying unit 70.
[00119] In any case, mixing of the high-pressure water
(water) and the abrasive may be uniformly performed while the
abrasive slurry passing through the conical coil by the
pressure of the sprayed high-pressure water stepwisely
collides from space having a small diameter to space having a
large diameter.
[00120] Next, the rotary mixing unit 110 in the present
invention device is illustrated in FIG.8. The mixing units in
FIGS. 6 and 7 are provided in a state of fixing a position,
such as a grid or conical coil, but the rotary type mixing
unit 110 of the present invention has the characteristics in
that mixability of the high-pressure water and the abrasive
may be further improved while the abrasive slurry collides to
idle as passing through the mixing units.
[00121] For example, as illustrated in a magnified portion
in FIG.8, other types of the rotary type mixing units of the
present invention may be provided as one or more rotors 114
connected to a rotational axis 112 disposed in the lower side
of the negative pressure space T in the device housing or
collision bars 118 having an inclined shape connected to the
rotational axis 112.
[00122] At this time, as illustrated in FIG. 8, the
rotational axis 112 may be provided in a bearing 116b fixed at
the center of connecting bars 116a connected to a fixing ring
116 provided inside the device housing.
32
[00123] Therefore, the rotational axis 112 rotates by the
medium of the bearing, and in particular, the rotors 114
included in the rotational axis are inclined in the shape
having twisted upper and lower portions, and abrasive
collision bars 114a may be further included in the rotors 114.
[00124] Eventually, when the high-pressure water is
injected inside the device housing at a high pressure, the
rotors forcibly rotate by the medium of the rotational axis as
the high-pressure water vertically injected collides therewith
and thus, mixing of the high-pressure water and the abrasive
may be more effectively performed.
[00125] Meanwhile, as illustrated in FIG. 8, in the case
that abrasive collision bars 118 inclined in a vertical
direction along the rotational axis 112 are installed instead
of the rotors, water and abrasive may be sufficiently mixed as
they collide with the collision bars.
[00126] At this time, in the case that the collision bars
118 are obliquely installed in the rotational axis, the
rotational axis 112 may rotate between bearings due to the
collision pressure of the high-pressure water passing
therethrough.
[00127] Eventually, the rotors 114 or the collision bars
118 included in the rotational axis 112 of the rotary type
mixing units 110 of the present invention allow the water and
the abrasive to be mixed as uniformly as possible, and then
allow them to be sprayed on the surface of the steel sheet
33
..
through the spraying unit 70.
[00128] That is, the mixing units 90, 100, and 110 of the
present invention uniformize a mixed state of the water and
the abrasive in the abrasive slurry sprayed from the device to
be able to effectively and uniformly remove scale on the
entire surface of the steel sheet when the abrasive slurry
collides with the surface of the steel sheet, and in
particular, to reduce the deviation of the average surface
roughness of the steel sheet after descaling. Therefore, the
foregoing appropriate surface roughness may be maintained and
as a result, quality may be improved by smoothly performing a
post-treatment process of the surface of the steel sheet.
[00129] Next, FIG. 5 illustrates the descaling device 1 of
the present invention described above and supplementary
facilities able to substantially supply the high-pressure
water and the abrasive to the device and process removed scale
2' and damaged glass bead abrasive 6' after spraying, and in
particular, to recycle the abrasive.
[00130] First, as illustrated in FIGS. 2 and 5, the
appropriate numbers of the descaling devices 1 of the present
invention are disposed above and under the steel sheet, the
chamber 120 surrounding the device and the moving steel sheet
in order to prevent scatter of the sprayed abrasive slurry 8
is disposed in a region having the descaling device 1 of the
present invention installed therein, and the steel sheet feed
rolls 122 for moving the steel sheet may be disposed at an
34
•
inner side of the chamber.
[00131] Although schematically illustrated in the drawings,
a collection hopper 124 for collecting the water 4 and the
abrasive 6 in the sprayed abrasive slurry 8 is installed in a
lower side of the chamber 120, and the sprayed abrasive slurry
8 is collected in a cyclone 126 through a pump pp and a valve
V and then introduced into a separation tank 128 installed
under the cyclone 126 for separating the collected scale 2'
and the damaged abrasive 6'.
[00132] Therefore, the water is collected in a water supply
tank 132 disposed below through an inner screen (no reference
numeral) of the separation tank 128 and the abrasive 6 is
provided to an abrasive supply hopper 54 connected to the line
L2 and the input hose 52 of the abrasive input unit 50
connected to the second connecting portion of the device
housing.
[00133] At this time, as illustrated in FIG. 5, new
abrasives 6a may be periodically supplied to the supply hopper
54 through a feeding unit and a screw 54a for discharging is
installed in a lower side of the supply hopper 54.
[00134] Meanwhile, water in the water collection tank 132
may be provided to the supply hose 40 of the high-pressure
water" supply unit 30 through a pumping device PP and a line L1.
[00135] At this time, overflow may be generated in the
separation tank 128 to allow the removed scale 2' and the
fractured abrasive 6' floated on the water to be introduced
35
•
into a treatment tank 130, and the scale 2' and the fractured
glass bead abrasive 6' passing through the treatment tank may
be finally treated by being respectively separated through a
magnetic separator 134.
[00136] Eventually, as illustrated in FIG. 5, the descaling
device 1 of the present invention is linked to the
supplementary facilities to collect the removed scale 2' and
the abrasive 6, and as a result, recycling of the abrasive may
be possible.
[00137] Meanwhile, the abrasive collected in the abrasive
separation tank in FIG. 5 may be provided to the abrasive
supply hopper 54 in a dried state by passing through a dryer
(no reference numeral-marked in dotted line).
[00138] Also, the collected water and the abrasive in FIG.
5 are provided to the line L2 through a pumping device to be
able to be supplied as a slurry form having the water and the
abrasive mixed therein to the hose 52 of the abrasive input
unit 50.
[00139] Next, a descaling operation through the foregoing
descaling device of the present invention will be summarized
below.
the device by the medium of the
formed through the high-pressure
process
specific
space
gravity is
negative
water 4
metal
5, in the
abrasive 6
FIGS. 3 to
invention, the
than that of
in
lower
the resent
illustrated
of
as
T
into
First,
pressure
[00140]
descaling
having a
introduced
36
..
injected inside the descaling device 1 without the application
of external pressure.
[00141] Next, the abrasive slurry 8 having the highpressure
water 4 and the abrasive 6 mixed in the mixing space
MX is sprayed on the surface of the steel sheet to remove
scale or other residual foreign objects on the surface of the
steel sheet.
[00142] At this time, as described above, the pressure of
the high-pressure water may be controlled to be in a range of
100 bar to 500 bar, and the abrasive having a specific gravity
lower than that of metal may be provided as glass beads (fine
balls) or ceramic beads having a diameter ranging from 10 pm
to 400 pm so as to maintain the average surface roughness of
the steel sheet after descaling in a range of 1 pm to 1.5 pm.
[00143] Meanwhile, examples through the foregoing descaling
device of the present invention will be described below.
[00144] (Example 1)
[00145] A scale treatment was performed on a hot-rolled low
carbon steel sheet (2.0 rom thickness x 1200 rom width) at a
line speed of 50 mpm based on the process described in FIG. 2
while the steel sheet was continuously passed under the
conditions of the following Table 3. As a result, a level of
residual scale was less than 1%, similar to that of a typical
hot-rolled steel sheet treated by pickling, an average surface
roughness of the steel sheet was 1.2 pm, and glossiness of the
surface thereof was also excellent.
37
20 rom,
50°C
) ,
een the
rom
t-rolled
width)
1. 2% of
process
allowing
ess than
1 sheet
he steel
eof was
:>
reased.
30 rom,
10°C
een the
rom
Abrasive (alumina, 100 llm),
spray pressure 150 bar
Treatment condition
Treatment condition
Abrasive (glass beads, 150-200 pm
spray pressure 200 bar
Elongation 1.2%, Amount of bending
Surface temperature of steel sheet
Elongation 1.2%, Amount of bending
Surface temperature of steel sheet
Spray angle 15 degrees, Spacing betw
device and the steel sheet 230
Spray angle 30 degrees, Spacing betw
device and the steel sheet 280
[Table 3]
[Table 4]
A scale treatment was performed on a ho
(Example 2)
Scale breaker
Category
Category
Scale breaker
Spray condition
Spray condition
High-pressure spray
of abrasive slurry
High-pressure spray
of abrasive slurry
[00146]
[00147]
[00148]
high-strength steel sheet (4.0 mID thickness x 1200 mID
treated by pickling, an average surface roughness of t
excellent and surface defects due to red scale were dec
[00149]
containing 0.1% of carbon, 1.2% of silicon, and
2%, similar to that of a typical hot-rolled stee
manganese at a line speed of 50 mpm based on the
described in FIG. 2 and under the conditions of the f
Table 4. As a result, a level of residual scale was 1
sheet was 1.5 pm, and glossiness of the surface ther
• ..'
•
38
•
[00150]
[00151]
(Example 3)
A scale treatment was performed on a hot-rolled low
carbon steei sheet (2.3 mm thickness x 1000 mm width) at a
line speed of 50 mpm based on the process described in FIG. 2
while the steel sheet was continuously passed under the
conditions of the following Table 5. As a result, a level of
residual scale was less than 1%, similar to that of a typical
hot-rolled steel sheet treated by pickling, an average surface
roughness of the steel sheet was 1.5 pm, and glossiness of the
surface thereof was excellent.
[00152] [Table 5]
Category
Scale breaker
High-pressure spray
of abrasive slurry
Spray condition
Treatment condition
Elongation 2.5%, Amount of bending 30 mm,
Surface temperature of steel sheet 50°C
Abrasive (glass beads, 80 ~),
spray pressure 300 bar
Spray angle 23 degrees, Spacing between the
device and the steel sheet 150 mm
[00153]
[00154]
(Example 4)
A scale treatment was performed on a hot-rolled low
carbon steel sheet (2.3 mm thickness x 1000 mm width) at a
line speed of 50 mpm based on the process described in FIG. 2
while the steel sheet was continuously passed under the
conditions of the following Table 6. As a result, a level of
residual scale was less than 1%, similar to that of a typical
hot-rolled steel sheet treated by pickling, an average surface
roughness of the steel sheet was 1.5 pm, and glossiness of the
39
•
surface thereof was excellent.
[00155] [Table 6]
Category
Scale breaker
High-pressure spray
of abrasive slurry
Spray condition
Treatment condition
Elongation 2.5%, Amount of bending 30 rnrn,
Surface temperature of steel sheet 50°C
Abrasive (glass beads, 100 ~),
spray pressure 300 bar
Spray angle 15 degrees, Spacing between the
device and the steel she~t 300 rnrn
[00156]
[00157]
[Industrial Applicability]
According to the present invention, descaling by
means of a physical (mechanical) method excluding a typical
chemical treatment may be realized and simplification of
device structure and descaling process may be possible. Also,
average surface roughness of a steel strip after descaling may
be appropriately maintained and the control thereof may be
possible, and thus, a highly efficient descaling and an
environmentally-friendly device may be eventually provided.
[00158] While the present invention has been shown and
described in connection with the exemplary embodiments, it
will be apparent to those skilled in the art that
modifications and variations can be made without departing
from the spirit and scope of the invention as defined by the
appended claims.

We Claim:
[Claim 1)
A descaling device comprising:
a device housing disposed in a feed path of a hot-rolled
steel strip;
a high-pressure fluid supply unit provided to supply a
high-pressure fluid to the device housing;
an abrasive input unit provided to introduce an abrasive
into the device housing; and
an abrasive slurry spraying unit provided in the device
housing to spray an abrasive slurry having the high-pressure
fluid and the abrasive mixed inside the device housing onto
the steel strip.
[Claim 2)
The descaling device as claimed in claim 1, wherein the
high-pressure fluid supply unit provided in the device housing
provides the high-pressure fluid by injecting the highpressure
fluid inside the device housing, and is configured to
smoothly introduce the abrasive into the inside of the device
housing by using injection pressure of the high-pressure fluid.
[Claim 3)
The descaling device as claimed in claim 1, wherein the
abrasive has a specific gravity lower than that of metal.
41
[Claim 4)
The descaling device as claimed in claim 3, wherein the
abrasive is formed of one of silicon oxide, silicon carbide,
aluminum oxide, glass, or a ceramic having a particle diameter
ranging from 10 pm to 400 pm.
[Claim 5)
The descaling device as claimed in claim 1, wherein the
device housing comprises:
a first connecting portion connected to the high-pressure
fluid supply unit;
a second connecting portion connected to the abrasive
input unit; and
a spraying unit assembly portion having the abrasive
slurry spraying unit assembled therein.
[Claim 6)
The descaling device as claimed in claim 1 or 5, wherein
the high-pressure fluid supply unit comprises:
a high-pressure fluid inlet provided inside the first
connecting portion included in the device housing and having
the high-pressure fluid supplied thereto; and
a high-pressure fluid nozzle provided to the highpressure
fluid inlet and having a nozzle hole formed therein
to inject the high-pressure fluid into the inside of the
device housing.
42
•
r
[Claim 7)
The descaling device as claimed in claim 6, wherein a
position of a horizontal line at a lower end of the highpressure
fluid nozzle is adjusted to meet with a center point
of an outlet of the inclined second connecting portion
included in the device housing.
[Claim 8)
The descaling device as claimed in claim 6, wherein the
high-pressure fluid is formed of high-pressure water injected
through the high-pressure fluid nozzle in a pressure range of
100 bar to 500 bar, and a spacing between the abrasive slurry
spraying unit included in the device housing and the steel
strip is in a range of 100 mm to 350 mm.
[Claim 9)
The descaling device as claimed in claim 2 or 5, wherein
the abrasive input unit comprises an abrasive input hose
connected to the second connecting portion included in the
device housing, and a negative pressure space allowing the
abrasive to be introduced into the device housing through
suction by the medium of injection pressure of the highpressure
fluid is formed inside the device housing.
[Claim 10)
The descaling device as claimed in claim 1 or 5, wherein
43
the abrasive slurry spraying unit comprises:
a spraying unit body provided in the spraying unit
assembly portion included in the device housing;
a depressed portion formed in an upper portion of the
spraying unit body; and
an abrasive slurry spray opening formed by penetrating
through the body from the depressed portion.
[Claim 11]
The descaling device as claimed in claim la, wherein the
depressed portion in the spraying unit body is concavely
formed to have a conical shape from an upper end of the
spraying unit body to an inner side thereof, and the spray
opening is formed as a slit formed by integrally penetrating
from a center of the conical depression portion to a lower end
of the body.
[Claim 12]
The descaling device as claimed in claim 11, wherein a
cut portion having a predetermined angle through the spray
opening is further formed at both sides of the lower end of
the spraying unit body.
[Claim 13]
The descaling device as claimed in claim 1, further
comprising a mixing unit provided in the device housing to
allow the high-pressure fluid and the abrasive to be smoothly
44
•
mixed therein.
[Claim 14)
The descaling device as claimed in claim 13, wherein the
mixing unit is provided as a fixed-type mixing unit formed of
one of one or more grid units provided between the highpressure
fluid supply unit and the abrasive slurry spraying
unit and one or more conical coils provided between the grid
units or independently provided in the device housing, or
provided as a combination thereof.
[Claim 15)
The descaling device as claimed in claim 13, wherein the
mixing unit is provided as a rotary type mixing unit included
in a rotational axis provided between the high-pressure fluid
supply unit and the spraying unit in the device housing and
comprising rotors or rotation bars rotated by collision of the
high-pressure fluid.
[Claim 16)
A descaling device substantially as herein described with
reference to forgoing examples and as illustrated in the
accompanying figures.