SYSTEM FOR CONTROLLING FLOW RATE OF COOLING WATER IN
CONTINUOUS CASTING
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates, in general, to a system
for controlling a flow rate of cooling water sprayed to a
metal section in continuous casting.
Description of the Related Art
FIG. 1 is a configuration diagram of a cooling unit
for a conventional continuous casting system, and FIG. 2 is
an enlarged view of driving rolls for a metal section shown
in FIG. 1.
Referring to FIGS. 1 and 2, the cooling unit for a
conventional continuous casting system includes a host
controller 1, a programmable logic controller 2, a pump 9,
a metal section 12, spray nozzles 8, a segment 10, driving
rolls 11, and the like.
Here, the programmable logic controller 2 serves to:
control opening and shutting of a cooling water-main pipe
via a motor-actuated shutoff valve 5; and to control
opening and shutting of flow control valves 3, depending on
flow rates detected by electromagnetic flow meters 4 which

are mounted at sub-pipes extended to respective flow
control loops from the main pipe.
However, since a ratio between a minimum flow rate and
a maximum flow rate in the conventional continuous casting
does not substantially exceed '10', owing to self-
limitations of flow control valves and the flow control
with only throttling action, the conventional flow control
valve has difficulty in simultaneous realization of weak
and strong cooling of metal section depending upon casting
speeds and various kinds of steel.
The foregoing is intended merely to aid in the
understanding of the background of the present invention,
and is not intended to mean that the present invention
falls within the purview of the related art that is
already known to those skilled in the art.
Documents of Related Art
(Patent Document 1) Korean Patent . No. 10-0528503
(published on November 7, 2005)
(Patent Document 2) Korean Laid-Open Patent
Publication No. 10-2013-0075883 (published on July 8, 2013)
SUMMARY OF THE INVENTION
Accordingly, the present invention has been made

keeping in mind the above problems occurring in the related
art, and an object of the present invention is to provide a
system for controlling a flow rate of cooling water in
continuous casting by widening the control range for the
flow rate of cooling water using a controller for
determining whether to allow a portion of cooling water to
bypass through a sub-pipe branching from one side of a main
pipe for spraying the cooling water towards a metal
section, thereby providing the simultaneous realization of
weak and strong cooling actions with the same continuous
casting machine, enabling the casting to be performed at a
wide range of casting speeds and for a variety of kinds of
steel.
It is proposed to provide a system for controlling a
flow rate of cooling water in continuous casting.
To this end, in an aspect, the present invention
provides a system for controlling a flow rate of cooling
water in continuous casting, the system including: a main
pipe having a main valve installed thereto; a sub-pipe
branching from the main pipe and having a sub-valve
installed thereto; and a controller serving to compare a
minimum flow rate of the cooling water set by the main
valve with a target flow rate of the cooling water to be
sprayed towards a metal section and, when the target flow

rate is determined to be smaller than the minimum flow
rate, to transmit an opening signal to the sub-valve to
allow a portion of cooling water to bypass through the sub-
pipe.
A flow meter may be provided on a tip of a nozzle
placed on the main pipe, through which the cooling water is
sprayed towards the metal section, to measure a flow rate
of the cooling water flowing therethrough, and the
controller may serve to compare in real time a flow rate of
the cooling water, measured by the flow meter, with the
target flow rate and, when determining the measured flow
rate to reach the target flow rate, transmit a shutoff
signal to the sub-valve.
A sub-flow meter may be provided on one side of the
sub-pipe to measure a flow rate of the cooling water
flowing therethrough, and the controller may serve to, when
the sub-flow meter detects a flow rate of the cooling water
corresponding to a difference between the minimum flow rate
and the target flow rate, transmit a shutoff signal to the
sub-valve.
According to the system for controlling the flow rate
of the cooling water in continuous casting, following
effects are obtained.
First, when adapted to the control of the flow rate of
the cooling water in continuous casting, very wide control

range for the flow rate of cooling water can be
advantageously obtained.
Second, the widening of the control range for the flow
rate of cooling water enables casting to be performed at a
wide range of casting speeds, and various kinds of steel
very susceptible to the flow rate of the cooling water can
be advantageously cast.
Third, the metal section can be subjected to weak and
strong cooling at the same time with the same continuous
casting machine.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages
of the present invention will be more clearly understood
from the following detailed description when taken in
conjunction with the accompanying drawings, in which:
FIG. 1 is a configuration diagram of a cooling unit
for a conventional continuous casting system.
FIG. 2 is an enlarged view of rolls for driving a
metal section, which was shown in FIG. 1.
FIG. 3 is a configuration diagram of a cooling unit in
a continuous casting system according to the present
invention.
FIG. 4 is a graph showing a wide controllable range of

a flow rate of cooling water, which can be obtained
according to the cooling system of the present invention.
FIG. 5 is a flowchart of a procedure of controlling a
flow rate of cooling water in continuous casting according
to the present invention.
FIGS. 6 and 7 are flowcharts of a procedure of
allowing required cooling water to bypass through a sub-
valve in order to allow a flow rate of the cooling water
corresponding to a target flow rate to be sprayed towards a
metal section.
DETAILED DESCRIPTION OF THE INVENTION
Hereinbelow, preferred embodiments of a system for
controlling a flow rate of cooling water in continuous
casting according to the present invention will be
described with reference to the accompanying drawings.
FIG. 3 is a diagram showing the entire configuration
of a system for controlling a flow rate of cooling water in
continuous casting, including a main pipe 100, a sub-pipe
200, and a controller 300.
Although not shown in the drawings, the main pipe 100
connects with a pump for supplying cooling water so that
cooling water to be sprayed towards a cast metal section
flows therethrough, and a main valve 110 is mounted onto

one site of the main pipe 100.
The main valve 110 has a predefined range of a flow
rate of cooling water to be sprayed therethrough towards
the metal section in association with a first flow meter
120 attached therearound, and cooling water is sprayed
through a spray nozzle 400 connected to an end of the main
pipe 100 within the predefined flow range.
As already described before, in regard to the range of
the flow rate of cooling water, there is a problem in that
a ratio between a minimum flow rate and a maximum flow rate
within the predefined control range does not exceed
approximately 10, since a valve itself has structural
limitations and the flow rate is controlled with only
throttling in the valve.
In the meantime, a sub-pipe 200 is mounted at one site
of the main valve 110 to allow a portion of cooling water
flowing through the main valve 110 to bypass through the
sub-pipe using a controller 300 which will be .described
later.
If a flow rate of cooling water to be sprayed towards
the metal section is smaller than a minimum flow rate
within a controllable flow rate set by the main valve 110,
a portion of cooling water is bypassed through the sub-pipe
200, thereby substantially widening the controllable range
of a flow rate of cooling water in the main valve 110.

The controller 300 is provided around the main pipe
100 and the sub-pipe 200 in order to control the flow rate
of the cooling water.
The controller 300 serves to compare the minimum flow
rate in the predefined range set by the main valve 110 with
a target flow rate, and according to the comparison
results, allow a portion of the cooling water to bypass
through the sub-pipe 200.
For instance, when the range of the flow rate of the
cooling water being controllable by the main valve 110
mounted to the main pipe 100 ranges from 40 L/min to 400 L/
min, and the target flow rate of the cooling water to be
sprayed towards the metal section at the spray nozzle 400
is 10 L/min, a problem occurs in that the main valve 110
cannot control the flow rate of the cooling water to 'be
sprayed towards the metal section.
When the present control system is not yet installed
on the actual spot, a ratio between the minimum flow rate
and the maximum flow rate to be sprayed through the main
valve 110 corresponds to approximately '4'.
Here,' the controller 300 of the control system has
already preset thereto a 'target flow rate' to be sprayed
towards the metal section, so the controller allows a
portion of the cooling water flowing through the main pipe
100 to bypass so that only the 'target flow rate' of

cooling water is sprayed from the spray nozzle 400 towards
the metal section, after comparing the ^target flow rate'
with the minimum flow rate in the range of the flow rate
set by the main valve 110.
A sub-valve 210 is also mounted at one site of the
sub-pipe 200 to allow the range of the flow rate of the
cooling water capable of flowing through the sub-pipe 200
to be controlled. Then, when determining the target flow
rate to be smaller than the minimum flow rate set by the
main valve 110, the controller 300 serves to transmit an
opening signal to the sub-valve 210 to allow a portion of
the cooling water flowing through the main pipe 100 to
bypass therefrom.
For instance, when the range of the flow rate of the
cooling water being controllable by the main valve 110
mounted to the main pipe 100 ranges from 40 L/min to 400 L/
min, and the target flow rate of the cooling water to be
sprayed towards the metal section through the spray-nozzle
400 is 10 L/min, since the minimum flow rate is 40 L/min
and the target flow rate is 10 L/min, the controller 300
transmits an opening signal to the sub-valve 210 to allow
the cooling water to flow at 30 L/min through the sub-pipe
200, thereby controlling the flow rate of the cooling water
to be sprayed at 10 L/min towards the metal section.
In the meantime, as shown in FIG. 3, a flow meter 500

is further provided on a tip of a nozzle (spray nozzle) for
spraying cooling water, as an element to determine whether
the cooling water sprayed towards the metal section while
being partially bypassed through the sub-pipe 200 has
reached a target flow rate or not.
Then, the controller 300 compares in real time the
flow rate of the cooling water, measured by the flow meter,
500 with the target flow rate and, when determining the
flow rate of the cooling water measured by the flow meter
500 to reach the target flow rate, transmits a shutoff
signal to the sub-valve 210.
That is, when the range of the flow rate of the
cooling water being controllable by the main valve 110
mounted to the main pipe 100 ranges from 40 L/min to 400 L/
min, and the target flow rate of the cooling water to be
sprayed towards the metal section through the spray nozzle
400 is 10 L/min, since the minimum flow rate is 40 L/min
and the target flow rate is .10 L/min, the controller 300
transmits an opening signal to the sub-valve 210 to allow
the cooling water to flow at 30 L/min through the sub-pipe
200, and then when the flow rate of the cooling water
measured by the flow meter 500 mounted on the tip of the
nozzle 400 continuously varies to reach 10 L/min, the
controller 300 transmits a shutoff signal to the sub-valve

210 mounted at one site of the sub-pipe 200.
Further, in order to widen the range of the flow rate
of the cooling water that is substantially controllable by
the main valve 110 mounted on the main pipe 100 with such a
control procedure, as shown in FIG. 3, a sub-flow meter 220
is mounted at one site of the sub-pipe 200 to measure the
flow rate of the cooling water flowing through the sub-pipe
200.
Here, the controller 300 is characterized by
transmitting a shutoff signal to the sub-valve 210 when the
flow rate measured by the sub-flow meter 220 reaches a flow
rate corresponding to a difference between the minimum flow
rate and the target flow rate.
That is, assuming that the range of the flow rate of
the cooling water being controllable by the main valve 110
mounted to the main pipe 100 ranges from 40 L/min to 400 L/
min, and the target flow rate of the cooling water to be
sprayed towards the metal section through the spray nozzle
400 is 10 L/min, when the flow rate measured by the sub-
flow meter 220 reaches 30 L/min that corresponds to a
difference between 40 L/min of the minimum flow rate and 10
L/min of the target flow rate, the controller 300 transmits
a shutoff signal to the sub-valve 210 so as to control the
flow rate of the cooling water to be sprayed at 10 L/min
towards the metal section through the spray nozzle 400.

With such configurations according to the present
invention, it can be seen from FIG. 4 that a ratio between
the minimum flow rate and the maximum flow rate is improved
to approximately '40' .
As shown, the minimum flow rate and the maximum flow
rate being controllable under a pressure ranging from 0.05
bar to 8 bar according to the present invention are 0.6
L/min and 25 L/min, respectively, so that a ratio
therebetween is advantageously improved to approximately
'40'.
In the meantime, the system for controlling a flow
rate of cooling water in continuous casting is operated as
follows.
As shown in FIG. 5, a stage S1 is carried out to set a
target flow rate of cooling water to be sprayed towards a
metal section.
Here, the flow rate of the cooling water to be sprayed
may be set to a low or high value in order to allow the
metal section to be cooled weakly or strongly.
The target flow rate is stored in the already-
mentioned controller, and is compared with a minimum flow
rate which will be described hereinbelow.
Next, a stage S20 is carried out to compare the target
flow rate with the minimum flow rate in a controllable
range of the flow rate set by the main valve, and when the

target flow rate is determined to be smaller than the
minimum flow rate, a stage S30 is carried out to set the
flow rate of the cooling water to the minimum flow rate in
the range of the flow rate being controllable by the main
valve.
For instance, when the target flow rate of the cooling
water to be sprayed towards the metal section is 10 L/min,
and the range of the flow rate being controllable by the
main valve is 40 to 400 L/min, since the target flow rate
is smaller than 40 L/min of the minimum flow rate, in this
case, the controller transmits a signal to the main valve
to fixedly set the flow rate of the cooling water capable
of flowing through the main valve to 4 0 L/min.
Next, a stage S40 is carried out to allow a portion of
the cooling water to bypass through the sub-pipe so that
the flow rate of the cooling water to be sprayed towards
the metal section reaches the target flow rate. In the
former case, 30 L/min of flow rate of cooling water in 40
L/min flow rate of the cooling water flowing through the
main valve flows through the sub-pipe.
The controller transmits an opening signal to the sub-
valve 210 mounted to the sub-pipe 200 to allow a portion of
the cooling water to bypass through the sub-pipe 200 so
that the portion of the cooling . water flows through the
sub-pipe.

In the meantime, as shown in FIG. 6, when the flow
rate of the cooling water to be sprayed towards the metal
section reaches the target flow rate in the process of the
cooling water being partly bypassed through the sub-pipe, a
procedure of preventing the cooling water from flowing
through the sub-pipe 200 is as follows.
After the bypassing of the portion of the cooling
water through the sub-pipe 200, a stage S50 is carried out
to compare in real time a flow rate measured by the flow
meter 500 mounted to the tip of the nozzle 400, through
which the cooling water is sprayed towards the metal
section, with the target flow rate, by the already-
mentioned controller.
As a result of comparison, when the measured flow rate
reaches the target flow rate, the controller transmits a
shutoff signal to the sub-valve 210 to prevent the
bypassing of the cooling water through the sub-pipe (S60).
Further, as shown in FIG. 7, when the target flow rate
of the cooling water is sprayed towards the metal section,
a procedure of preventing the cooling water from flowing
through the sub-pipe 200 is as follows.
After the bypassing of the portion of the cooling
water through the sub-pipe, a stage S70 is carried out to
detect whether the flow rate measured by the sub-flow meter
220 mounted to one side of the sub-valve 210 has reached a

flow rate corresponding to a difference between the minimum
flow rate and the target flow rate, and when the measured
flow rate has reached the flow rate corresponding to the
difference, a shutoff signal is transmitted to the sub-
valve 210.
Although a preferred embodiment of the present
invention has been described for illustrative' purposes,
those skilled in the art . will appreciate that various
modifications, additions and substitutions are possible,
without departing from the scope and spirit of the
invention as disclosed in the accompanying claims.

WHAT IS CLAIMED IS:
1. A system for controlling a flow rate of cooling
water in continuous casting, the system comprising:
a main pipe having a main valve installed thereto;
a sub-pipe branching from the main pipe and having a
sub-valve installed thereto; and
a controller serving to compare a minimum flow rate of
the cooling water set by the main valve with a target flow
rate of the cooling water to be sprayed towards a metal
section and, when the target flow rate is determined to be
smaller than the minimum flow rate, to transmit an opening
signal to the sub-valve to allow a portion of cooling water
to bypass through the sub-pipe.
2. The system according to claim 1, wherein a flow
meter is provided on a tip of a nozzle placed on the main
pipe, through which the cooling water is sprayed towards
the metal section, to measure a flow rate of the cooling
water flowing therethrough, and the controller serves to
compare in real time a flow rate of the cooling water,
measured by the flow meter, with the target flow rate and,
when determining the measured flow rate to reach the target
flow rate, transmit a shutoff signal to the sub-valve.

3. The system according to claim 1 or 2, wherein a
sub-flow meter is provided on one side of the sub-pipe to
measure a flow rate of the cooling water flowing
therethrough, and the controller serves to, when the sub-
flow meter detects a flow rate of the cooling water
corresponding to a difference between the minimum flow rate
and the target flow rate, transmit a shutoff signal to the
sub-valve.