KR102265199B1 - Apparatus for spraying cooling medium - Google Patents

Abstract

A cooling medium injection device is disclosed. As a cooling medium injection device for cooling a slab in a continuous casting machine segment according to an embodiment of the present invention, a nozzle body receiving and spraying a cooling medium, a flow path formed in the nozzle body to move the cooling medium, and a cooling medium installed in the flow path A plurality of orifices and orifices for accelerating the flow are arranged at predetermined intervals along the flow path.

Description

Cooling medium injection device {APPARATUS FOR SPRAYING COOLING MEDIUM}

The present invention relates to a cooling medium injection device, and more particularly, to a cooling medium injection device used to cool a cast slab in a segment of a continuous casting machine.

In general, a continuous casting process is a process of continuously solidifying liquid molten steel into a predetermined solid phase, and a plurality of nozzles provided in a segment are used to cool a slab during a continuous casting operation.

1 is a view showing a general continuous casting process. Molten steel is injected into the tundish (3) through the long nozzle (2) from the ladle (1) containing the molten steel that has completed the refining process, and the molten steel temporarily stored in the tundish (3) is transferred to the tundish (3) and the mold ( 4) It is injected into the mold 4 through the molten steel delivery device 5 located in between, and as it solidifies through primary cooling in the mold 4 and secondary cooling at the bottom of the mold 4, the billet ( Billet), bloom, slab, etc. refers to a series of processes to produce slabs (6).

Molten steel discharged through the mold 4 goes through primary cooling in the mold 4, and the surface is somewhat solidified between the upper frame and the lower frame provided in the segment 10 of the continuous casting device. At this time, cooling water is sprayed through the plurality of nozzles 11 for rapid solidification of the molten steel, and the shape of the cast steel to be manufactured is continuously changed through secondary cooling.

Here, since the secondary cooling is a method of directly spraying the slab 6, it is a quality-directed equipment, and in particular, when strong cooling is applied and the slab 6 temperature falls in the embrittlement region, cracks in the slab 6 only with a small tensile force. can be induced In order to prevent this, it is necessary to keep the cooling of the cast slab 6 uniform. If non-uniform cooling is applied, the temperature of the cast slab 6 locally corresponds to the embrittlement region, and if an external force such as a tensile force acts at that time, cracks are induced. Therefore, uniform secondary cooling technology is a very important issue in the playing process.

The best method for uniform cooling is a method using an air mist cooling nozzle that mixes and sprays cooling water and air as shown in FIG. 2 .

Air and cooling water are mixed in the mixing unit 12 constituting the nozzle, and orifices are respectively installed at the air inlet and the cooling water inlet to drop pressure and to facilitate fluid mixing. At this time, when the amount of cooling water is small, the size of the orifice tends to be small, and when the diameter of the orifice is very small, the nozzle clogs the orifice with foreign substances. When nozzle clogging occurs, uniform cooling is not guaranteed, and this causes the aforementioned cracking problem.

Korea Patent Publication No. 2016-0020732 (published on Feb. 24, 2016)

Embodiments of the present invention are cooling that can solve the difficulty of uniform cooling due to blockage of the orifice due to poor quality of secondary cooling water during continuous casting operation, foreign substances such as scale generated when water is sprayed on the slab, impact generated during segment detachment, etc. It is intended to provide a media injection device.

According to one aspect of the present invention, there is provided a cooling medium injection device for cooling a cast slab in a continuous casting machine segment, a nozzle body receiving and spraying a cooling medium, a flow path formed in the nozzle body so that the cooling medium moves, and a flow path in the flow path An orifice installed to accelerate the flow of the cooling medium and a plurality of orifices arranged at predetermined intervals along the flow path may be provided.

The nozzle body may include a spout through which the cooling medium is ejected, and a direction of the spout may be positioned in the same direction as a moving direction of the cooling medium in the flow path.

The number N of the orifices may satisfy the following equation.

, 여기서, d1은 원 오리피스 직경(하나의 오리피스 사용시), d2는 확장된 오리피스 직경(복수의 오리피스 사용시), N은 소수점 첫째자리에서 사사오입하여 얻을 수 있는 자연수.formula

, where d1 is the diameter of one orifice (when one orifice is used), d2 is the diameter of the expanded orifice (when multiple orifices are used), and N is a natural number obtained by rounding off from the first decimal place.

The nozzle body may include a spout through which the cooling medium is ejected, and a direction of the spout may be positioned perpendicular to a moving direction of the cooling medium in the flow path.

The number N of the orifices may satisfy the following equation.

, 여기서, d1은 원 오리피스 직경(하나의 오리피스 사용시), d2는 확장된 오리피스 직경(복수의 오리피스 사용시), N은 소수점 첫째자리에서 사사오입하여 얻을 수 있는 자연수.formula

, where d1 is the diameter of one orifice (when one orifice is used), d2 is the diameter of the expanded orifice (when multiple orifices are used), and N is a natural number obtained by rounding off from the first decimal place.

The flow path includes an air flow path through which air moves, a cooling water flow path through which cooling water moves, a merging flow path where the air flow path and the cooling water flow path join, and a mixed flow path through which the cooling medium mixed in the merging flow path moves, The orifice includes a plurality of air orifices disposed at predetermined intervals along the air flow path and a plurality of cooling water orifices disposed at predetermined intervals along the cooling water flow path.

Embodiments of the present invention can perform uniform cooling of the slab by reducing the clogging of the nozzle used for secondary cooling during continuous casting operation.

1 schematically shows a general continuous casting machine.
2 schematically shows an air mist cooling nozzle used in a conventional continuous casting machine.
3 is a view showing a cooling medium injection device according to an embodiment of the present invention.
4 is a chart showing the relationship between the coolant amount and the coolant orifice diameter when one orifice is used for the main continuous casting machine.
5 is a schematic diagram illustrating a plurality of orifices disposed in a flow path according to the present embodiment.
6 is a chart showing the number of necessary orifices according to the expanded orifice size according to the present embodiment.
7 is a schematic diagram illustrating a nozzle flow path according to another embodiment of the present invention.
8 is a chart showing the number of necessary orifices according to the size of the orifices installed in the flow path of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments introduced below are provided as examples in order to sufficiently convey the spirit of the present invention to those of ordinary skill in the art to which the present invention pertains. The present invention is not limited to the embodiments described below and may be embodied in other forms. In order to clearly explain the present invention, parts irrelevant to the description are omitted from the drawings, and in the drawings, the width, length, thickness, etc. of components may be exaggerated for convenience. Like reference numerals refer to like elements throughout.

3 is a view showing a cooling medium injection device according to an embodiment of the present invention.

Referring to FIG. 3 , the cooling medium spraying device 20 according to the embodiment of the present invention includes a nozzle body 30 that receives and sprays a cooling medium.

The nozzle body 30 includes an air inlet 31 receiving air, a cooling water inlet 32 receiving cooling water, and an outlet 33 through which a cooling medium is ejected toward the cast slab.

The air inlet 31 may be connected to the air supply pipe through the nipple 31a, and the cooling water inlet 32 may be connected to the cooling water inlet pipe through the nipple 32a.

The nozzle tip 34 may be coupled to the jet port 33 , and the cooling medium may be sprayed toward the slab through the nozzle tip 34 .

A flow path 40 through which the cooling medium moves may be formed inside the nozzle body 30 , and an orifice 50 for accelerating the flow of the cooling medium may be installed in the flow path 40 .

The flow path 40 has one end connected to the air inlet 31 and an air flow path 41 through which the air supplied through the air inlet 31 moves, and one end connected to the cooling water inlet 32 and the cooling water inlet 32 . The cooling water flow path 42 through which the cooling water supplied through the flow path 42 moves, the merging flow path 43 where the air flow path 41 and the cooling water flow path 42 join, and the mixing flow path 43 where the cooling medium merged in the merging flow path 43 moves A flow path 44 may be included. An end of the mixing passage 44 may be connected to the jet port 33 .

The orifice 50 may include a plurality of air orifices 51 installed in the air flow passage 41 and a plurality of cooling water orifices 52 installed in the coolant flow passage 42 .

When the amount of cooling water in the orifice 50 is small, the size of the orifice 50 also tends to be small, and when the diameter of the orifice 50 is very small, nozzle clogging may occur in which foreign substances block the orifice 50 .

To prevent this, in this embodiment, a plurality of orifices 50 may be installed inside the flow path 40 to satisfy the diffusion effect, which is the original orifice 50 role, while increasing the size of the orifice 50 . .

A plurality of air orifices 51 may be disposed at predetermined intervals along the air flow path 41 , and a plurality of cooling water orifices 52 may also be disposed at predetermined intervals along the cooling water flow path 42 . In this embodiment, the air orifice 51 is arranged at three places, and the cooling water orifice 52 is arranged at two places, but the number of these orifices can be varied according to the diffusion effect of the orifice as described below. have.

4 is a chart showing the relationship between the coolant amount and the coolant orifice diameter when one orifice is used for the main continuous casting machine. Based on a large amount of experience, the present applicant found that when the diameter of the orifice 50 was within 2 mm, nozzle clogging occurred severely, and the amount of cooling water at this time was 5 L/min.

5 is a schematic diagram illustrating a plurality of orifices disposed in a flow path according to the present embodiment, and FIG. 6 is a chart showing the required number of orifices according to the expanded orifice size according to the present embodiment.

The flow path 40 shown in FIG. 5 may be an air flow path 41 or a coolant flow path 42 , and the orifice 50 may be an air orifice 51 or a coolant orifice 52 .

First, the orifice 50 induces a pressure drop according to Equation 1, the flow is dissipated, and spreads like a jet to exert a mixing effect.

[Equation 1]

는 오리피스 전후 압력차,

는 밀도, v는 유속, K는 오리피스의 손실계수를 의미하며 노즐마다 다르며 오리피스의 직경이 작을수록 커진다.here,

is the pressure difference before and after the orifice,

where is the density, v is the flow rate, and K is the loss factor of the orifice, which is different for each nozzle. The smaller the diameter of the orifice, the larger it is.

On the other hand, in the case of weak cooling, since the diameter of the orifice is small, K is very large.

If multiple orifices are used, Equation 1 can be expressed as Equation 2 below.

[Equation 2]

Here, i is the number of each orifice, and N is the total number of orifices.

If a larger diameter orifice is used, Ki will be less than Kc, and if multiple such orifices are used, the total K value is the sum of each Ki value.

Here, when the sum of all K is equal to Kc, it is defined as an equivalent loss factor.

That is, as in Equation 3, when a plurality of orifices having a diameter equal to Kc are used, it is the same as in the case of using one orifice having a small diameter Kc in terms of pressure loss.

[Equation 3]

For example, the diameter of the orifice and the number of orifices may be obtained as follows.

Summarizing Equation 2, the flow rate is defined as Equation 4.

[Equation 4]

The flow rate Q can be defined by Equation 5 multiplied by the area by the velocity.

[Equation 5]

Here, C is the orifice flow coefficient and d is the diameter of the orifice.

As described above, when one orifice is used and the diameter (d1) of the orifice where nozzle clogging occurs is 2 mm, when the diameter of the orifice is increased to d2, the number of orifices having an equivalent loss factor is the pressure difference in both cases as follows. It can be defined by Equation 6 under the condition that and the flow rate are the same.

[Equation 6]

where d1 is the diameter of one orifice (when using one orifice), and d2 is the diameter of the expanded orifice (when using multiple orifices).

6 is a graphical representation of this. As shown in FIG. 6 , if the expanded diameter d2 of the orifice 50 is set to 2.6 mm, it can be seen that the required number N of orifices is three. Here, N is a natural number obtained by rounding off from the first decimal place.

On the other hand, as shown in FIG. 7 , when the direction of flow is rapidly changed, that is, the direction of the jet port 33 formed in the nozzle body 30 is positioned perpendicular to the moving direction of the cooling medium in the flow path 40 (90 degrees). bent tube type), the loss factor K = 0.5, so Equation 6 can be expressed as Equation 7 below.

[Equation 7]

delete

8 is a graph showing Equation (7). Accordingly, when there is a pipe with a changed flow path, the number of orifices required according to the orifice size can be known.

In the above, specific embodiments have been shown and described. However, it is not limited to the above-described embodiment, and those of ordinary skill in the art to which the invention pertains will be able to make various changes without departing from the spirit of the invention described in the claims below.

10: segment, 20: coolant injector,
30: nozzle body, 31: air inlet,
32: coolant inlet, 33: outlet,
34: nozzle tip, 40: euro,
41: air flow path, 42: coolant flow path,
43: combined euro, 44: mixed euro,
50: orifice, 51: air orifice,
52: coolant orifice.

Claims (6)

delete delete A cooling medium injection device for cooling a cast slab in a continuous casting machine segment, comprising:
a nozzle body receiving and spraying a cooling medium;
a flow path formed in the nozzle body to move the cooling medium;
an orifice installed in the flow path to accelerate the flow of the cooling medium; and
A plurality of orifices are arranged at predetermined intervals along the flow path,
The nozzle body includes an outlet through which the cooling medium is ejected,
The direction of the spout is located in the same direction as the moving direction of the cooling medium in the flow path,
The number (N) of the orifices is a cooling medium injection device that satisfies the following equation.
formula

, where d1 is the diameter of one orifice (when one orifice is used), d2 is the diameter of the expanded orifice (when multiple orifices are used), and N is a natural number obtained by rounding off from the first decimal place. delete A cooling medium injection device for cooling a cast slab in a continuous casting machine segment, comprising:
a nozzle body for receiving and spraying a cooling medium;
a flow path formed in the nozzle body to move the cooling medium;
an orifice installed in the flow path to accelerate the flow of the cooling medium; and
A plurality of orifices are arranged at predetermined intervals along the flow path,
The nozzle body includes an outlet through which the cooling medium is ejected,
The nozzle body includes an outlet through which the cooling medium is ejected,
The direction of the spout is positioned perpendicular to the moving direction of the cooling medium in the flow path,
The number (N) of the orifices is a cooling medium injection device that satisfies the following equation.
formula

, where d1 is the diameter of one orifice (when one orifice is used), d2 is the diameter of the expanded orifice (when multiple orifices are used), and N is a natural number obtained by rounding off from the first decimal place. 6. The method of claim 3 or 5,
The flow path includes an air flow path through which air moves, a cooling water flow path through which cooling water moves, a merging flow path where the air flow path and the cooling water flow path join, and a mixed flow path through which the cooling medium mixed in the merging flow path moves,
wherein the orifice includes a plurality of air orifices spaced apart from each other along the air passage and a plurality of coolant orifices spaced apart from each other along the cooling water passage.

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