JP2000256815A - Cooling device for molten metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling device which does not develop disturbance and has a simple structure. SOLUTION: In the case a cooling element assembly 20 during waiting is necessary to cool molten metal 69, this assembly may be dipped into the molten metal 69 as the arrow mark 7. In the case the cooling is unnecessary, the cooling element assembly 20 is fully separated from a pot 68 as the arrow mark 6. By fully separating the cooling element assembly 20 from the pot 68, the upper surface of the molten metal 69 is not covered. Therefore, fume of the molten metal 69 is not brought into contact with the cooling element assembly 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a cooling device suitable for a hot-dip plating bath.

[0002]

2. Description of the Related Art FIG. 9 is a diagram showing the principle of a conventional hot-dip metal plating line.
02 and a cooling zone 103, a downwardly extending cylindrical snout 105 is extended from the cooling zone outlet 104 of the continuous furnace 101,
This is a continuous processing equipment in which the lower end of the snout 105 is inserted into a molten metal 107 of a molten metal plating tank 106 called a pot. The first outlet roll 1 provided at the cooling zone outlet 104 is annealed by heating to a predetermined temperature in 102, holding it, and cooling it in the cooling zone 103.
09 and the second exit roll 110 guide the wire in an S-shape, change the direction from horizontal to oblique as shown by the arrow, and then immerse it in the molten metal 107 to produce a large amount of metal-plated steel sheet. .

[0003] The molten metal plating bath 106 is provided with a heater 111 so that the molten metal is maintained at a predetermined temperature. In addition, if the molten metal plating tank 106 is formed of a metal container, the container may be attacked by the molten metal, and in recent years, a ceramic container is preferably used.
By the way, although the coil 108 is forcibly cooled in the cooling zone 103, there is retained heat, and the retained heat warms the molten metal 107. Here, if the plating tank 106 is a ceramic container having a higher heat insulating property than metal, the heat input is superior to the heat radiation, and the phenomenon that the temperature of the molten metal is too high occurs.

In view of this, for example, a refrigerant flow pipe 2 as shown in FIGS. 1 to 3 (a) and (b) of Japanese Utility Model Application Laid-Open No. 2-136055 entitled "Apparatus for adjusting temperature of molten metal plating bath".
It is necessary to have a technique of sinking the plating material (described in the publication) into the plating bath 10 and forcibly lowering the temperature of the plating bath 10.

[0005]

The refrigerant flow pipe 2 shown in FIG. 1 (front view) of the above publication is supported by left and right elevating mechanisms 5a and 5b having a large supporting span, so that the central portion thereof is directed downward. There is a possibility that the pipe is largely bent, and it is necessary to employ a large-diameter pipe in order to suppress the bending. In addition, the right and left elevating mechanisms 5a and 5b raise and lower, however, the horizontal part 3 is long and the vertical pipes (two right and left parts) rising from the horizontal part 3 are short, so that the horizontal part is changed with temperature change. When the portion 3 expands and contracts greatly, the effect acts on the vertical pipe, and the stress in the vertical pipe tends to be excessive. Also, the first
According to FIG. 2 which is a plan view of FIG.
Block the upper surface of the plating bath 10 and make it difficult to see the molten metal, which is not preferable.

Further, in the above publication, the refrigerant flow pipe 2 in FIG. 3 (a) is a complicated meandering pipe, and the refrigerant flow pipe 2 in FIG. 3 (b) is a complicated lattice structure. The production cost increases due to the complicated structure. In addition, in the refrigerant flow pipe 2 of FIG. 3 (b), since the connecting portions between the tubes 4c, 4c and the tubes 4d, 4d, 4d are immersed in the molten metal, it can be said that these connecting portions are easily broken.

As described above, the conventional refrigerant flow pipe 2 has a problem that it is obstructive and has a complicated structure. Therefore, an object of the present invention is to provide a cooling device which is not obstructive and has a simple structure.

[0008]

Means for Solving the Problems To achieve the above object, a first aspect of the present invention is a molten metal cooling apparatus for forcibly cooling a molten metal by pouring the molten metal into a pot from above. The cooling element of the apparatus is connected to a U-bend, first and second vertical pipes that are sufficiently long rising from both ends of the U-bend, a refrigerant supply pipe connected to the first vertical pipe, and a second vertical pipe. And a refrigerant supply pipe,
1st vertical pipe, U bend, 2nd vertical pipe, and refrigerant discharge pipe
It is characterized by having a structure to pass. Since the cooling device is the injection type cooling device, the cooling device can be removed from the pot when it is not necessary, and there is no possibility that the cooling device is obstructed.

[0009] Since the main part is a simple structure having a U-shape, the manufacturing cost can be reduced. In addition, since the first and second vertical tubes rising from both ends of the U-bend are lengthened, expansion and contraction accompanying a thermal change is large in the vertical direction and small in the horizontal direction. Since the structure of the main part is U, expansion and contraction in the vertical direction can be freely performed, and since the displacement in the horizontal direction is small, there is no fear that the stress becomes excessive.

In a second aspect, a cooling element group in which a plurality of the cooling elements according to the first aspect are arranged in parallel, an element holder for supporting the plurality of the cooling elements at a predetermined pitch, and the number of the cooling elements in a large-diameter pipe. The same number of branch pipes are attached and the refrigerant supply header arranged outside the pot, a sufficiently long inlet-side flexible pipe extending from the branch pipe of the refrigerant supply header to the refrigerant supply pipe of each cooling element, and a large-diameter pipe. A refrigerant recovery header attached to the same number of branch pipes as the number of the cooling elements and arranged outside the pot, and a sufficiently long outlet flexible pipe extending from the refrigerant discharge pipe of each cooling element to the branch pipe of the refrigerant recovery header. , From which a cooling device for molten metal is formed.

The arrangement of the header outside the pot means that the header is completely removed from the pot when viewed two-dimensionally. Refrigerant flows in the order of refrigerant supply header → multiple branch pipes → multiple inlet flexible pipes → multiple cooling elements → multiple outlet flexible pipes → multiple branch pipes → refrigerant recovery header. . There is no need to worry about corrosion by the molten metal because the branch pipe is at a position where it does not touch the molten metal. Further, the refrigerant flowing through one refrigerant supply header is divided into a large number of cooling elements and flows, and is collected by one refrigerant recovery header. The small-diameter, large number of cooling elements can increase the heat exchange area and can perform cooling more efficiently than the large-diameter, small number of cooling elements.

According to a third aspect of the present invention, at least a portion of the cooling element that is immersed in the molten metal is made of heat-resistant steel having durability even under conditions that do not allow the passage of the refrigerant, and is provided between the branch pipe of the refrigerant supply header and the refrigerant supply pipe. A throttle valve for reducing the flow rate of the refrigerant. Here, the minimum flow rate is maintained at such an amount that the refrigerant does not boil. This is because when boiling, gas is mixed into the refrigerant, which hinders the flow of the refrigerant. If it is necessary to reduce the cooling capacity, the throttle valve may be throttled. If the supply of refrigerant is reduced, the cooling element may rise to the temperature of the molten metal. Therefore, heat resistance steel is used for a necessary portion of the cooling element to maintain durability.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings should be viewed in the direction of reference numerals. FIG. 1 is a side view of a cooling element employed in the present invention.
The first and second vertical pipes 12 and 13, which are sufficiently long standing from both ends of the U-bend 11, the refrigerant supply pipe 14 connected to the first vertical pipe 12, and the second vertical pipe 13, respectively. And a refrigerant discharge pipe 15 for supplying refrigerant to the refrigerant supply pipe 14 as shown by the arrow.
The first vertical pipe 12 → the U-bend 11 → the second vertical pipe 13 → the refrigerant discharge pipe 15 makes one pass in this order.

In this example, a single stainless steel pipe having a diameter of 25 mm to 50 mm is bent by a bender to obtain the shape shown in the figure. Stainless steel pipes of various materials including SUS304 are manufactured, but SUS316L (components are shown in Table 1) is adopted in consideration of corrosion resistance to molten metal (zinc) and durability against temperature rise.

[0015]

[Table 1]

Since it contains 16 to 18% of Cr (% by weight; the same applies hereinafter), it has excellent oxidation resistance, contains 2 to 3% of Mo and 12 to 16% of Ni, has excellent high-temperature strength, and has a C of 0.1 to 0.1%. Since it is suppressed to 03 or less, precipitation of carbide can be suppressed, and as a result, the material is excellent in corrosion and durability.
Such cooling elements 10 can be put to practical use by combining a plurality of cooling elements.

FIG. 2 is a perspective view of a cooling element assembly according to the present invention. As for the cooling element assembly 20, for example, 13 cooling elements 10...
The same applies hereinafter. ) Are arranged in parallel so that the cooling element groups arranged in parallel are not separated by the upper element holder 30 and the lower element holder 40.

The cooling element 10 can be divided into two types: a large-diameter pipe to reduce the number thereof, and a small-diameter pipe to increase the number thereof as in this embodiment.

[0019]

[Table 2]

If a 125A × Sch80 (schedule No. 80, nominal diameter 125 standard product) tube is selected as a large diameter tube, the inside area of this tube is 115 cm ² , and the surface area of the tube is 0.44 m ² per m. is there. 32A as small diameter pipe
If a × Sch80 tube is adopted, the internal area per tube of this tube is 8.5 cm ² , and the total of 13 tubes is 11
Since it is 0.5 cm ² , it is equivalent to one 125A. The surface area per tube of 32A × Sch80 tube is 0.13 m ² per m, and the total of 13 tubes is 1.7 m ² . Since this 1.7 m ² is about 4 times that of 0.44 m ^2, by employing the large number of small diameter tubes, indicating that can be extended four times the heat transfer area, i.e. the heat exchange area. The present invention is characterized in that the adoption of a small-diameter tube has been realized, whereas the adoption of a small-diameter tube has conventionally been difficult for reasons of strength.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2, and the upper element holder 30 includes, for example, a top plate 31 and a bottom plate 32.
Are connected by left and right side plates 33, 33, and the cooling elements 10 are connected to the top plate 31 and the bottom plate 32 by U bolts 34.
Is fixed. With this, the cooling element 10 ...
Can be integrated with the top plate 31 or the bottom plate 32 at a predetermined pitch. In addition, 35, 35 are eye plates (hole plates), and are plates for hanging hanging wires.

Since the lower element holder 40 shown in FIG. 2 has almost the same structure as the upper element holder 30,
Description is omitted. However, the eye plates 35, 35 are not provided in the lower element holder 40.

Next, a valve stand for efficiently supplying and recovering the refrigerant to the plurality of cooling elements 10 will be described. FIG. 4 is a perspective view of a valve stand employed in the present invention. The valve stand is a three-dimensional stand in which a large number of valves are arranged so that they can be easily operated. An electric bogie 53 provided with 52... That can be driven by a motor (not shown)
, A refrigerant supply header 55 and a refrigerant recovery header 60 are placed on the branch pipe 56 of the refrigerant supply header 55.
.. and a branch pipe 61 of the refrigerant recovery header 60.
. Are provided with throttle valves 62. Incidentally, 58 is a main supply hose and 63 is a main recovery hose.

More specifically, the refrigerant supply header 55 is composed of a large-diameter pipe and branch pipes 56 having a small diameter corresponding to the number of cooling elements (see FIG. 2).
・ This is the distributor where the branch is made. Similarly, the refrigerant recovery header 60 is a merging device obtained by branching small-diameter branch pipes 61... Into a large-diameter pipe by the number of cooling elements (see FIG. 2). The throttle valve 57 is basically attached to the branch pipe 56, but may be provided anywhere between the branch pipe 56 and the refrigerant supply pipe 14. The same applies to the throttle valve 62.

A cooling apparatus for molten metal which integrates the cooling element assembly 20 and the valve stand 50 described above will be described below. FIG. 5 is a layout view of the cooling element assembly and the valve stand according to the present invention. The cooling element 10 of the cooling element assembly 20 suspended from the elevated rail 65 via electric hoists 66, 66 is used to melt the pot 68. This cooling element 1 is immersed in metal 69
0, the refrigerant is sent as shown by an arrow through the main supply hose 58, the refrigerant supply header 55, and the inlet side flexible tube 71, and the outlet side flexible tube 72, as shown by the arrow, from the cooling element 10.
This indicates that the refrigerant is recovered via the refrigerant recovery header 60 and the main recovery hose 63.

Here, reference numeral 74 denotes an auxiliary trolley, which is a simple trolley for supporting the main supply hose 58 and the main recovery hose 63. By supporting the main supply hose 58 and the main recovery hose 63 with the auxiliary cart 74, the main supply hose 58 and the main recovery hose 63 can be freely moved in the horizontal direction in the drawing. If the auxiliary cart 74 is not used, the main supply hose 58 and the main recovery hose 63 will rub against the floor 75, and the main supply hose 58 and the main recovery hose 63 will be worn out.

FIG. 6 is a plan view of the molten metal cooling device, taken along line 6-6 in FIG.
Are a cooling element group in which a plurality of cooling elements 10 are arranged in parallel, and an element holder (an upper element holder 30 and a lower element holder 40. The element holders support the plurality of cooling elements 10 at a predetermined pitch. The number of holders may be one or three or more, and the number is arbitrary.)
The same number of branch pipes 56 are attached and the refrigerant supply header 55 arranged outside the pot 68, and the branch pipes 56 of the refrigerant supply header 55
A sufficiently long entry-side flexible pipe 71 extending to the refrigerant supply pipe 14, a refrigerant recovery header 60 arranged outside the pot 68, and a branch pipe 61 of the refrigerant recovery header 60 And a sufficiently long outlet flexible pipe 72 extending from the refrigerant discharge pipe 15 of each cooling element 10.

In particular, the branch pipes 56 of the refrigerant supply header 55
· And refrigerant supply pipes 14 of a large number of cooling elements 10 ···
Are connected by inlet flexible pipes 71, respectively, and similarly, the refrigerant discharge pipes 15 of the cooling elements 10 and the branch pipes 61 of the refrigerant recovery header 60 can be output. This shows that they are connected by the flexible tube 72. Refrigerant supply header 55 and refrigerant recovery header 60
At the roots of the branch pipes 56 and 61, stress tends to concentrate and is easily affected by molten metal. Such branch pipes 56 and 61
Is arranged on the floor 75 sufficiently distant from the pot 68, there is no fear that the branch pipes 56, 61 will be damaged. That is, the only part affected by the molten metal 69 is the cooling element 10.
Is a very simple bent tube, and there is no fear of being damaged by the molten metal 69.

Since two throttle valves 57 and 62 are provided for one cooling element 10, the amount of refrigerant supplied can be controlled by restricting both or one of the throttle valves 57 and 62. Therefore, the cooling capacity can be easily controlled.

The operation of the cooling element 10 and the molten metal cooling device 80 having the above-described structures will be described below. FIG.
FIG. 4 is a functional view of the cooling element of the present invention. The cooling element 10 of the present invention has a structural feature that a sufficiently long first vertical pipe 12 and a second vertical pipe 13 are respectively set up from both ends of a U-bend 11. As is clear from FIG.
Since the first vertical pipe 12 is suspended from the refrigerant pipe 15 and the second vertical pipe 13 is suspended from the refrigerant discharge pipe 15, the first and second vertical pipes 1 are suspended.
2, 13 and the U-bend 11 can be extended as shown by the arrows. For this purpose, the first and second vertical tubes 1
2 and 13 generate only tensile stress and hardly any bending stress.

In the case of the conventional cooling pipe which is extended horizontally, the bending becomes large, so that it is necessary to increase the section modulus and the second moment of area. Therefore, a large-diameter pipe or a thick-walled pipe is necessarily employed. I can't. In this regard, in the present embodiment, since the cooling pipe is extended vertically, there is no need to worry about bending rigidity, and a small-diameter pipe or a thin-walled pipe can be employed. More specifically, in the drawing, the height of the main part of the cooling element 10 is H,
The width of the main part is W, and in this embodiment, H = 3 × W. S
Assuming that the linear expansion coefficient of US316L is about 1.9 × 10 ⁻⁶ , the temperature when immersed in molten metal is 80 ° C., and H is 800 mm, the thermal expansion in the direction of the arrow is 1.9 × 10 ⁻⁶ ×. 8
0 × 800 = 1.2 mm, horizontal direction is 1/3 of 0.4 m
m. Therefore, the influence of thermal expansion and contraction can be considered in the direction of the arrow.

FIG. 8 is a view for explaining the operation of the molten metal cooling device of the present invention. The wire is wound up by electric hoists 66, 66, and the lower surface of the cooling element 10 is raised to a height of a floor 75 or higher. The cooling element assembly 20 can be completely separated from the pot 68 by pulling the cooling element assembly 20 along the arrow as shown by the arrow. In this state, the cooling element 1
It is sufficient that the inlet-side flexible tube 71 and the outlet-side flexible tube 72 are detached from zero. By completely separating the cooling element assembly 20 from the pot 68, there is nothing covering the upper surface of the molten metal 69 and no fumes (steam) of the molten metal 69 touch the cooling element assembly 20.

As described above, the present invention provides the cooling element 10.
Instead of simply raising and lowering, the cooling elements 10... Can be retracted outside the pot 68 by adding a horizontal pulling operation to the raising and lowering. If it is necessary to cool the molten metal 69, the refuge cooling element assembly 20 may be immersed in the molten metal 69 as shown by the arrow.

The cooling element 10 has a U-bend 11
And the first and second vertical pipes 12 and 13 are welded, the first vertical pipe 12 and the refrigerant supply pipe 14 are welded, and the second vertical pipe 13 and the refrigerant discharge pipe 1 are welded.
5 can be welded. If it is a welded structure, U
The bend 11 and the first and second vertical pipes 12 and 13 are made of a high-grade material,
By using a low-grade material for the refrigerant supply pipe 14 and the refrigerant discharge pipe 15, the cost can be reduced. However, FIG.
If one pipe is bent by only a bender as in the cooling element 10 described above, it is preferable because the welded portion is eliminated, the flow of the refrigerant becomes smoother, and there is no need to consider corrosion of the weld metal.

In addition to the heat-resistant steel in the narrow sense, any type of heat-resistant steel can be used as long as it has the required heat resistance.

[0036]

According to the present invention, the following effects are exhibited by the above configuration. Since the molten metal cooling device of the first aspect is a throw-in type cooling device, the cooling device can be removed from the pot when it is not necessary, and there is no fear that the cooling device is obstructed. And since the main part is a simple structure having a U-shape,
Manufacturing costs can be reduced. In addition, since the first and second vertical tubes rising from both ends of the U-bend are lengthened, expansion and contraction accompanying a thermal change is large in the vertical direction and small in the horizontal direction. Since the structure of the main part is U, expansion and contraction in the vertical direction can be freely performed, and since the displacement in the horizontal direction is small, there is no fear that the stress becomes excessive.

In the cooling apparatus for molten metal according to the present invention, the refrigerant is supplied to the refrigerant supply header → a plurality of branch pipes → a plurality of inlet flexible pipes → a plurality of cooling elements → a plurality of outlet flexible pipes. →
Pour a plurality of branch pipes → refrigerant recovery header in this order. There is no need to worry about corrosion by the molten metal because the branch pipe is at a position where it does not touch the molten metal. Further, the refrigerant flowing through one refrigerant supply header is divided into a large number of cooling elements and flows, and is collected by one refrigerant recovery header. The small-diameter, large number of cooling elements can increase the heat exchange area and can perform cooling more efficiently than the large-diameter, small number of cooling elements.

According to a third aspect of the present invention, at least a portion of the cooling element that is immersed in the molten metal is made of heat-resistant steel having durability even under conditions that do not allow the passage of the refrigerant, and is provided between the branch pipe of the refrigerant supply header and the refrigerant supply pipe. Is provided with a throttle valve for reducing the flow rate of the refrigerant. If it is necessary to reduce the cooling capacity, the throttle valve may be throttled. If the supply of refrigerant is reduced, the cooling element may rise to the temperature of the molten metal.
Therefore, heat resistance steel is used for a necessary portion of the cooling element to maintain durability.

[Brief description of the drawings]

FIG. 1 is a side view of a cooling element employed in the present invention.

FIG. 2 is a perspective view of a cooling element assembly according to the present invention.

FIG. 3 is a sectional view taken along line 3-3 in FIG.

FIG. 4 is a perspective view of a valve stand employed in the present invention.

FIG. 5 is a layout diagram of a cooling element assembly and a valve stand according to the present invention.

6 is a view taken in the direction of arrows 6-6 in FIG. 5;

FIG. 7 is an operation diagram of the cooling element of the present invention.

FIG. 8 is an explanatory view of handling of the molten metal cooling device of the present invention.

FIG. 9 is a principle diagram of a conventional hot-dip metal plating line.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Cooling element, 11 ... U bend, 12 ... 1st vertical pipe, 13 ... 2nd vertical pipe, 14 ... Refrigerant supply pipe, 15 ... Refrigerant discharge pipe, 20 ... Refrigerant element assembly, 30 ... Element holder (upper element Holder), 40 ... Element holder (lower element holder), 55 ... Refrigerant supply header, 56, 61 ... Branch pipe, 57, 62 ... Throttle valve, 60 ...
Refrigerant recovery header, 68 pot, 69 molten metal, 71
… Incoming side flexible tube, 72… out side flexible tube, 80… cooling device for molten metal.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akira Miyazaki 3 Oaza Hikari, Kashima-shi, Ibaraki Sumitomo Metal Industries Kashima Works F-term (reference) 4K027 AA02 AA22 AB42 AD26

Claims (3)

[Claims] 1. A cooling apparatus for molten metal for forcibly cooling molten metal by pouring the molten metal from above into a molten metal filled in a pot, wherein a cooling element of the apparatus is provided with a U-bend and two ends of the U-bend. The first and second vertical pipes each having a sufficiently long standing length, a refrigerant supply pipe connected to the first vertical pipe, and a refrigerant discharge pipe connected to the second vertical pipe.
1st vertical pipe, U bend, 2nd vertical pipe, and refrigerant discharge pipe
A cooling device for molten metal characterized by having a structure for passing. 2. A cooling element group in which a plurality of cooling elements according to claim 1 are arranged in parallel, an element holder for supporting a plurality of cooling elements at a predetermined pitch, and a large-diameter pipe having the same number as the number of cooling elements. A refrigerant supply header attached to the branch pipe and arranged outside the pot; a sufficiently long inlet-side flexible pipe extending from the branch pipe of the refrigerant supply header to the refrigerant supply pipe of each cooling element; And a refrigerant recovery header disposed outside the pot while attaching the same number of branch pipes, and a sufficiently long outlet flexible pipe extending from the refrigerant discharge pipe of each cooling element to the branch pipe of the refrigerant recovery header. Cooling device for molten metal. 3. A part of the cooling element, which is immersed in at least the molten metal, is made of heat-resistant steel having durability even under a condition that does not allow a refrigerant to pass therethrough, and is provided between a branch pipe of the refrigerant supply header and a refrigerant supply pipe. 3. The cooling apparatus for molten metal according to claim 2, further comprising a throttle valve for reducing a flow rate of the refrigerant.