Method and system for cooling strip material

Details Method and system for cooling strip material Method and system for cooling strip material

2000-12-04

2003-03-25

Lamb, Brenda A. (Department: 1734)

Coating apparatus

With heat exchange, drying, or non-coating gas or vapor...

Cooling

C118S067000

Reexamination Certificate

active

06537374

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a method and a system for cooling a high temperature strip material in two steps.
BACKGROUND OF THE INVENTION
As an example of equipment with a system for cooling a high temperature strip material, a hot dip galvanizing system is shown in FIG.
3
. This system comprises a hot dip galvanizing tank
60
, a heater
71
, a soaking device
72
, and a mist cooler
80
as a cooling device.
According to the above system, a steel strip
50
is galvanized in the hot dip galvanizing tank
60
, moved vertically upward, and heated with the heater
71
to alloy the zinc with the steel. The alloyed steel strip
50
is soaked over its entire width by means of the soaking device
72
. This steel strip
50
traveling in a cooling zone C is cooled with the mist cooler
80
from 520° C. to 200° C., and carried horizontally by a deflector roll
90
.
The mist cooler
80
is composed of mist sprayers
81
disposed in opposing positions at both sides of the ascending steel strip
50
. Each mist sprayer
81
comprises water supply pipes
82
and air supply pipes
83
arranged vertically in rows such that each air supply pipe
83
is mounted inside each water supply pipe
82
in a double-pipe configuration. Each water supply pipe
82
has many nozzle holes made along the width of the steel strip
50
, and each air supply pipe
83
has many nozzle holes made along the width of the steel strip
50
. The mist cooler
80
forms mists
86
from water
84
in the water supply pipes
82
by jetting air
85
through the nozzles of the air supply pipes
83
, and directs the mists
86
toward the surfaces of the steel strip
50
to cool it.
With the foregoing mist cooler
80
, mists
86
with a constant water volume density were sprayed on both sides of the steel strip
50
throughout the cooling zone C to cool the steel strip
50
. At a site in the cooling zone C where the temperature of the steel strip
50
was about 350° C. or lower (i.e., an upper portion of the cooling zone C), however, the mists
86
adhering to the surfaces of the steel strip
50
underwent transition boiling, rapidly cooling the steel strip
50
. Transition boiling refers, in terms of water, to a phenomenon involving transition from a state of cooling with water vapor to a state of direct cooling with water, or to a state of cooling with a mixture of water and water vapor. This phenomenon takes place at about 350° C. Thus, nonuniform temperature distribution of the steel strip
50
was liable to occur, thereby deforming the steel strip
50
, resulting in its malformation.
SUMMARY OF THE INVENTION
The present invention has been accomplished to solve the above-described problems.
According to a first aspect of the present invention, there is provided a method for cooling a strip material, comprising:
passing the strip material, which is traveling, through a high temperature cooling zone and a low temperature cooling zone in this order, to cool the strip material with a high water volume air-water mixture in the high temperature cooling zone, and then cooling the strip material with a low water volume air-water mixture in the low temperature cooling zone.
According to a second aspect of the present invention, there is provided a method for cooling a strip material, comprising:
passing the strip material, which is traveling, through a high temperature cooling zone and a low temperature cooling zone in this order, to cool the strip material with a high water volume air-water mixture in the high temperature cooling zone to a temperature in the vicinity of a temperature at which transition boiling occurs, and then cooling the strip material with a low water volume air-water mixture in the low temperature cooling zone while suppressing transition boiling.
The air-to-water ratio of the high water volume air-water mixture may be about 1500, and the air-to-water ratio of the low water volume air-water mixture may be about 5000.
The above method may further comprise:
cooling the strip material in the high temperature cooling zone to a temperature in the vicinity of a temperature at which transition boiling occurs; and
cooling the strip material in the low temperature cooling zone to a predetermined temperature.
In the above method, the passing step may include the sub-steps of:
cooling the strip material to about 350° C. in the high temperature cooling zone, and
cooling the strip material from about 350° C. to a predetermined temperature in the low temperature cooling zone.
According to a third aspect of the present invention, there is provided a system for cooling a strip material, comprising:
a high temperature cooling zone and a low temperature cooling zone established as cooling zones, in which the strip material is cooled with a high water volume air-water mixture in the high temperature cooling zone, and cooled with a low water volume air-water mixture in the low temperature cooling zone.
In this system, the air-to-water ratio of the high water volume air-water mixture may be about 1500, while the air-to-water ratio of the low water volume air-water mixture may be about 5000.
In the above system, the high temperature cooling zone may cool the strip material to about 350° C., while the low temperature cooling zone may cool the strip material from about 350° C. to a predetermined temperature.
According to a fourth aspect of the present invention, there is provided a system for cooling a traveling strip material, comprising:
a high temperature cooling zone and a low temperature cooling zone established along a direction in which the strip material travels;
a high water volume air-water mixture cooler installed in the high temperature cooling zone for cooling the strip material with a high water volume air-water mixture to a temperature in the vicinity of a temperature at which transition boiling occurs; and
a low water volume air-water mixture cooler installed in the low temperature cooling zone for cooling the strip material with a low water volume air-water mixture while suppressing transition boiling.
The high water volume air-water mixture cooler may spray high water volume mists onto both sides of the strip material, and the low water volume air-water mixture cooler may spray low water volume mists onto both sides of the strip material.
The high water volume air-water mixture cooler may include a multiplicity of spray pipes arranged vertically, each spray pipe having a water supply pipe for supplying a high water volume, and an air supply pipe mounted inside the water supply pipe, the water supply pipe extending in the direction of the width of the strip material and having a plurality of nozzle holes drilled facing a surface of the strip material, and the air supply pipe having a plurality of nozzle holes drilled in the direction of the width of the strip material. The low water volume air-water mixture cooler, on the other hand, may include a multiplicity of spray pipes arranged vertically, each spray pipe having a water supply pipe for supplying a low water volume, and an air supply pipe mounted inside the water supply pipe, the water supply pipe extending in the direction of the width of the strip material and having a plurality of nozzle holes drilled facing a surface of the strip material, and the air supply pipe having a plurality of nozzle holes drilled in the direction of the width of the strip material.
According to a fifth aspect of the present invention, there is provided a galvanizing system for galvanizing a strip material, comprising:
a hot dip galvanizing tank which galvanizes the strip material;
a heater that heats the galvanized strip material;
a soaking device that soaks the heated strip material;
a high temperature cooling zone which cools the soaked strip material by spraying a high water volume air-water mixture thereon; and
a low temperature cooling zone which cools the soaked strip material, after cooling in the high temperature cooling zone, by spraying a low water volume air-water mixture thereon.
The hot dip galvanizing tank may contain molten zinc.
The prese

Affiliated with

Also associated with

Rating

Method and system for cooling strip material does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method and system for cooling strip material, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and system for cooling strip material will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3077945