阅读说明：本技术 一种可更换炉底的转炉及初次砌筑的施工方法 (Converter with replaceable converter bottom and construction method for primary building ) 是由 吕仁祥 刘在春 王之龙 纪怀杰 李庆涛 刘吉良 于 2021-09-13 设计创作，主要内容包括：本发明公开了一种可更换炉底的转炉及初次砌筑的施工方法,包括可拆卸的转炉底壳和转炉身壳,所述转炉身壳内侧上砌筑有炉身耐火材料,所述转炉底壳上砌筑有炉底耐火材料,转炉底壳连接在所述转炉身壳上,所述炉身耐火材料与炉底耐火材料之间形成环形缝隙,炉身耐火材料在环形缝隙一侧的立表面上粘贴有隔离层,所述转炉在初次砌筑时环形缝隙中填充有专用的捣打接缝料,隔离层隔绝了炉身耐火材料与捣打料之间的黏连结合,因此当转炉炉底热更换时,炉身耐火材料与捣打料之间极易脱离,易于拆卸和清理,提高了炉底热更换的施工效率,接缝料分多层填料捣实,确保了施工质量,减缓了钢水对接缝料的侵蚀速度,大大提高了转炉初次砌筑时的使用寿命。(The invention discloses a converter with a replaceable furnace bottom and a construction method for primary building, which comprises a detachable converter bottom shell and a converter body shell, wherein a furnace body refractory material is built on the inner side of the converter body shell, a furnace bottom refractory material is built on the converter bottom shell, the converter bottom shell is connected to the converter body shell, an annular gap is formed between the furnace body refractory material and the furnace bottom refractory material, an isolation layer is pasted on the vertical surface of one side of the annular gap by the furnace body refractory material, a special ramming seam material is filled in the annular gap during primary building of the converter, the isolation layer isolates the adhesive combination between the furnace body refractory material and the ramming material, therefore, when the converter bottom is subjected to thermal replacement, the furnace body refractory material and the ramming material are easy to separate, the disassembly and the cleaning are easy, the construction efficiency of thermal replacement of the furnace bottom is improved, the seam material is tamped by multiple layers of fillers, and the construction quality is ensured, the corrosion speed of the molten steel to the joint material is slowed down, and the service life of the converter during primary masonry is greatly prolonged.)

1. The utility model provides a converter of removable stove bottom, includes detachable converter drain pan and converter body shell, it has furnace body refractory material to build by laying bricks or stones on the converter body shell inboard, it has stove bottom refractory material to build by laying bricks or stones on the converter drain pan, the converter drain pan is fixed on the converter body shell, form annular gap, its characterized in that between furnace body refractory material and the stove bottom refractory material: the furnace body refractory material is characterized in that an isolation layer is adhered to the vertical surface on one side of the annular gap, and the annular gap is filled with a special ramming joint material during the primary building of the converter.

2. The converter with a replaceable floor according to claim 1, wherein: the isolating layer is made of aluminum foil paper, glass fiber aluminum foil cloth, pure cotton cloth or carbon fiber cloth.

3. The converter with a replaceable floor according to claim 1, wherein: the thickness of isolation layer is 0.01 ~ 5 mm.

4. The converter with a replaceable floor according to claim 1, wherein: the width of the annular gap is 30-100 mm.

5. The converter with a replaceable floor according to claim 1, wherein: the ramming joint material is prepared by mixing a solid material and a liquid material, wherein the solid material comprises 60-75 wt% of fused magnesia particles, 10-20 wt% of fused magnesia fine powder, 5-15 wt% of high-iron high-calcium sand fine powder, 2-6 wt% of medium-temperature asphalt fine powder, 1-2 wt% of metal aluminum powder, 1-2.5 wt% of silicon carbide fine powder and 1-1.5 wt% of solid resin, and the liquid material is 1.5-5 wt% of washing oil or 1.5-5 wt% of diesel oil.

6. The converter with a replaceable floor according to claim 5, wherein:

the content of MgO in the fused magnesia particles is more than 96 wt%, the particle size is 0.088-5 mm,

the MgO content in the electric melting magnesite fine powder is more than 96wt percent, the grain diameter is less than 0.088mm,

the content of MgO in the high-iron high-calcium sand fine powder is more than 81 wt%, and Fe₂O₃The content of the CaO is 5-7 wt%, the content of CaO is 8-12 wt%, the grain diameter is less than 0.088mm,

the softening point of the medium-temperature asphalt fine powder is 100-130 ℃, the residual carbon content is more than 52 percent, the particle size is less than 1mm,

the Al content in the metal aluminum powder is more than 98 wt%, the grain diameter is less than 0.088mm,

the SiC content in the silicon carbide fine powder is more than 98 percent, the grain diameter is less than 0.088mm,

the solid resin is phenolic resin special for refractory materials, the grain size is less than 0.15mm,

the water content in the washing oil is less than 0.5 wt%.

7. The converter with a replaceable floor according to claim 1, wherein: and a gas supply and powder spraying system penetrates between the bottom shell of the converter and the refractory material at the bottom of the converter.

8. A construction method for the initial building of a converter with a replaceable converter bottom is characterized by comprising the following steps:

a. firstly, accurately metering a solid material, adding the solid material into a mixing roll for dry mixing for 4-5 minutes, slowly adding the accurately metered liquid material into the mixing roll within 1-2 minutes, and continuously mixing for 10 minutes to obtain the pug after mixing, namely the rammed joint material.

b. Building refractory materials on the inner side of the converter body shell, adhering the isolation layer to the vertical surface at the bottom of the converter body refractory materials after building is completed, and then fixing the converter bottom shell with built furnace bottom refractory materials on the converter body shell;

c. then filling and tamping an annular gap between the furnace body refractory material and the furnace bottom refractory material by adopting a ramming joint material;

d. and after the annular gap is filled, standing the converter for 0.5-1 hour, and then baking the converter, wherein the time for heating the converter from room temperature to 1000 ℃ is controlled to be more than 1.5 hours during baking, and the converter is continuously baked for 1 hour after the temperature is more than 1000 ℃, so that the converter can be used for smelting.

9. The construction method for the initial masonry of the converter with the replaceable bottom according to claim 8, characterized in that: and c, repeating the filling and tamping process of the ramming joint material in multiple layers until the annular joint is filled with the filler and tamped, wherein each layer of the filler is controlled to be 150-200 mm, and the density of the rammed joint material is ensured to be more than 2.50g/cm³And the isolating layer pasted on the vertical surface of the refractory material of the furnace body is avoided from being damaged in the process of ramming the filler.

Technical Field

The invention relates to the field of smelting equipment, in particular to a converter with a replaceable furnace bottom and a construction method for primary masonry.

Background

The converter is mainly used for producing carbon steel, alloy steel and smelting copper and nickel, and is the most common steelmaking equipment used at present. With the improvement of steel smelting technology in China, the converter bottom blowing oxygen and powder spraying smelting mode is gradually emphasized by steel enterprises, the oxygen bottom blowing converter blowing method can ensure that the stirring intensity of a molten pool is severe, oxygen flow is uniformly dispersed and blown into the molten pool, the influence of an upper slag layer on the reaction in the converter is less, and unexpected smelting effects and other excellent smelting characteristics can be obtained through spraying iron ore powder or returning a mixture of slag and lime powder into the furnace bottom.

In the process of smelting by blowing oxygen at the bottom of a converter, the service life of refractory materials at the bottom of the converter is difficult to synchronize with that of refractory materials at the furnace body, and in order to improve the utilization rate of the refractory materials at the furnace body and the steelmaking efficiency, the refractory materials at the bottom of the converter need to be thermally replaced in the subsequent production, so the treatment quality and the construction method of the joint between the refractory materials at the bottom of the converter and the refractory materials at the furnace body are particularly important when the converter is built for the first time, but the following problems exist in the current process: firstly, the joint material is not filled in a real way during the first building, so that the service life of the converter is reduced, and phenomena such as pulverization, shedding, erosion, steel leakage and the like are easy to occur; secondly, can discover during the hot change of furnace bottom that the joint material of using when building by laying bricks or stones for the first time combines with the refractory material of furnace body is easy to glue, leads to joint material and the refractory material of furnace body difficult to break away from, is difficult for clearing up, influences the efficiency of construction that the hot change of furnace bottom, this is the problem that prior art exists.

Disclosure of Invention

In order to make up for the defects of the prior art, the invention provides a converter with a replaceable furnace bottom and a construction method for primary masonry, so as to solve the problems in the prior art.

The invention is realized by the following technical scheme: the utility model provides a converter of removable stove bottom, includes detachable converter drain pan and converter body shell, it has furnace body refractory material to build by laying bricks or stones on the converter body shell inboard, it has furnace bottom refractory material to build by laying bricks or stones on the converter drain pan, the converter drain pan is fixed on the converter body shell, form annular gap between furnace body refractory material and the furnace bottom refractory material, furnace body refractory material pastes on the vertical surface of annular gap one side has the isolation layer, the converter is filled with dedicated ramming seam material in the annular gap when building by laying bricks or stones for the first time.

Preferably, the isolation layer is made of aluminum foil paper, glass fiber aluminum foil cloth, pure cotton cloth or carbon fiber cloth.

Further optimally, the thickness of the isolation layer is 0.01-5 mm.

Further optimally, the width of the annular gap is 30-100 mm.

Preferably, the ramming joint material is prepared by mixing a solid material and a liquid material, wherein the solid material comprises 60-75 wt% of fused magnesia particles, 10-20 wt% of fused magnesia fine powder, 5-15 wt% of high-iron high-calcium sand fine powder, 2-6 wt% of medium-temperature asphalt fine powder, 1-2 wt% of metal aluminum powder, 1-2.5 wt% of silicon carbide fine powder and 1-1.5 wt% of solid resin, and the liquid material is 1.5-5 wt% of wash oil or 1.5-5 wt% of diesel oil.

Further optimally, the content of MgO in the fused magnesia particles is more than 96 wt%, and the particle size is 0.088-5 mm; the MgO content in the fused magnesia fine powder is more than 96 wt%, and the grain diameter is less than 0.088 mm; the content of MgO in the high-iron high-calcium sand fine powder is more than 81 wt%, and Fe₂O₃The content of the CaO is 5-7 wt%, the content of CaO is 8-12 wt%, and the grain diameter is less than 0.088 mm; the softening point of the medium-temperature asphalt fine powder is 110-120 ℃, the residual carbon content is more than 52%, and the particle size is less than 1 mm; the Al content in the metal aluminum powder is more than 98 wt%, and the particle size is less than 0.088 mm; the SiC content in the silicon carbide fine powder is more than 98 percent, and the grain size is less than 0.088 mm; the solid resin is phenolic resin special for refractory materials, and the particle size is less than 0.15 mm; the water content in the washing oil is less than 0.5 wt%.

Further optimally, a gas supply and powder spraying system penetrates between the bottom shell of the converter and the refractory material at the bottom of the converter.

Further optimally, the construction method for the initial building of the converter with the replaceable converter bottom comprises the following steps:

a. firstly, accurately metering a solid material, adding the solid material into a mixing roll for dry mixing, wherein the dry mixing time is 4-5 minutes, slowly adding the accurately metered liquid material into the mixing roll within 1-2 minutes, and continuously mixing for 10 minutes, wherein the pug after mixing is the rammed joint material;

b. building refractory materials on the inner side of the converter body shell, adhering the isolation layer to the vertical surface at the bottom of the converter body refractory materials after building is completed, and then fixing the converter bottom shell with built furnace bottom refractory materials on the converter body shell;

c. then filling and tamping an annular gap between the furnace body refractory material and the furnace bottom refractory material by adopting a ramming joint material;

d. and after the annular gap is filled, standing the converter for 0.5-1 hour, and then baking the converter, wherein the time for raising the temperature from low temperature to 1000 ℃ is controlled to be more than 1.5 hours during baking the converter, and the temperature is higher than 1000 ℃ and then the baking is continued for 1 hour, so that the converter can be used for smelting.

Preferably, in the step c, in the process of filling and tamping the ramming joint material, the filling and tamping are repeated in multiple layers until the annular joint is filled and tamped, wherein each layer of filling is controlled to be 150-200 mm, and the density of the rammed joint material after being tamped is ensured to be more than 2.50g/cm³And the isolating layer pasted on the vertical surface of the refractory material of the furnace body is avoided from being damaged in the process of ramming the filler.

The invention has the beneficial effects that:

1) an isolation layer is adhered to the vertical surface of one side of the annular gap made of the refractory material of the furnace body, and the isolation layer has good tensile strength regardless of adopting aluminum foil paper or glass fiber aluminum foil cloth, so that the isolation layer is not easy to damage in the construction ramming process; in addition, because the aluminum foil material has a higher melting point (660 ℃), low-melting-point organic volatile matters in the joint ramming material gradually volatilize in the heating process, high-melting-point organic matters are gradually carbonized after the temperature is increased to 300 ℃, and the isolation layer isolates the adhesive combination between the furnace body refractory material and the ramming material, so that the furnace body refractory material and the ramming material are easily separated when the converter bottom needs to be thermally replaced, the converter bottom is easy to disassemble and clean, the damage to the furnace body refractory material is avoided, and the construction efficiency of thermal replacement of the converter bottom is greatly improved.

2) By adopting the construction method, the joint material is tamped by multiple layers of fillers, the construction quality is ensured, the steel leakage accident is avoided, the corrosion speed of molten steel to the joint material is slowed down, and the service life of the converter during primary building is greatly prolonged.

3) The ramming joint material adopts wash oil or diesel oil to soften fine asphalt powder and then infiltrate the fine fused magnesia powder and the fused magnesia particles to play a role in wetting and bonding, the joint material has good ramming and compacting construction effects due to the addition of the fine asphalt powder and the wash oil, and the fine asphalt powder is gradually carbonized at high temperature to form carbon chain combination with the fine fused magnesia particles and the fine fused magnesia powder, so that the joint material has good high-temperature strength and performance. In addition, the joint material mixed by the method is stored in a plastic sealing bag, and can keep the plastic stability for a long time at a certain environmental temperature.

Drawings

FIG. 1 is a schematic sectional view of a converter according to the present invention

In the figure, 2, a converter body shell; 3. a shaft refractory; 4. furnace bottom refractory material; 5. ramming the joint material; 6. an isolation layer; 7. a gas supply and powder injection system; 8. a bottom shell of the converter.

Detailed Description

In order to clearly illustrate the technical features of the present invention, the present invention is explained in detail by the following embodiments. The experimental procedures used in the following examples are all conventional procedures unless otherwise specified.

As shown in fig. 1, a converter with a replaceable converter bottom comprises a detachable converter bottom shell 8 and a converter body shell 2, a furnace body refractory material 3 is built on the inner side of the converter body shell 2, a furnace bottom refractory material 4 is built on the converter bottom shell 8, the converter bottom shell 8 is fixed on the converter body shell 2, an annular gap is formed between the furnace body refractory material 3 and the furnace bottom refractory material 4, the width of the annular gap is 30-100 mm, an isolation layer 6 is pasted on the vertical surface of the furnace body refractory material 3 on one side of the annular gap, the thickness of the isolation layer 6 is 0.01-5 mm, and a special ramming joint material 5 is filled in the annular gap when the converter is built for the first time.

In a preferred embodiment, the material of the isolation layer 6 may be aluminum foil paper, glass fiber aluminum foil cloth, pure cotton cloth, or carbon fiber cloth material.

In a preferred embodiment, the ramming joint compound 5 is prepared by mixing a solid material and a liquid material, wherein the solid material comprises 60-75 wt% of fused magnesia particles, 10-20 wt% of fused magnesia fine powder, 5-15 wt% of high-iron high-calcium sand fine powder, 2-6 wt% of medium-temperature asphalt fine powder, 1-2 wt% of metal aluminum powder, 1-2.5 wt% of silicon carbide fine powder and 1-1.5 wt% of solid resin, and the liquid material is 1.5-5 wt% of washing oil or 1.5-5 wt% of diesel oil.

In a preferred embodiment, the content of MgO in the fused magnesia particles is more than 96 wt%, and the particle diameter is 0.088-5 mm; the MgO content in the fused magnesia fine powder is more than 96 wt%, and the grain diameter is less than 0.088 mm; the content of MgO in the high-iron high-calcium sand fine powder is more than 81 wt%, and Fe₂O₃The content of the CaO is 5-7 wt%, the content of CaO is 8-12 wt%, and the grain diameters of the CaO and the CaO are all less than 0.088 mm; the softening point of the medium-temperature asphalt fine powder is 110-120 ℃, the residual carbon content is more than 52%, and the particle size is less than 1 mm; the Al content in the metal aluminum powder is more than 98 wt%, and the particle size is less than 0.088 mm; the SiC content in the silicon carbide fine powder is more than 98 percent, and the grain size is less than 0.088 mm; the solid resin is phenolic resin special for refractory materials, and the particle size is less than 0.15 mm; the water content in the washing oil is less than 0.5 wt%.

In a preferred embodiment, a gas supply and powder injection system 7 is inserted between the bottom shell 8 of the converter and the refractory 4 of the bottom of the converter.

A construction method for the initial building of a converter with a replaceable converter bottom comprises the following steps: a. firstly, accurately metering a solid material, adding the solid material into a mixing roll for dry mixing, wherein the dry mixing time is 4-5 minutes, slowly adding the accurately metered liquid material into the mixing roll within 1-2 minutes, and continuously mixing for 10 minutes, wherein the pug after mixing is the rammed joint material; b. building refractory material on the inner side of the converter body shell, and adhering the isolation layer on the vertical surface of the bottom of the refractory material of the converter body after buildingThen fixing the bottom shell of the converter built with the furnace bottom refractory material on the shell of the converter body; c. then, filling and tamping annular gaps between the furnace body refractory material and the furnace bottom refractory material by adopting tamping joint materials, repeating filling and tamping in multiple layers in the filling and tamping process of the tamping joint materials until the annular gaps are completely filled and tamped, wherein each layer of filling is controlled to be 150-200 mm, and the density of the tamped tamping joint materials is ensured to be more than 2.50g/cm³And the isolating layer pasted on the vertical surface of the refractory material of the furnace body is avoided from being damaged in the process of ramming the filler; d. and after the annular gap is filled, standing the converter for 0.5-1 hour, and then baking the converter, wherein the time for raising the temperature from low temperature to 1000 ℃ is controlled to be more than 1.5 hours during baking the converter, and the temperature is higher than 1000 ℃ and then the baking is continued for 1 hour, so that the converter can be used for smelting.

Example 1:

a converter with a replaceable converter bottom is shown in figure 1 and comprises a detachable converter bottom shell 8 and a converter body shell 2, a furnace body refractory material 3 is built on the inner side of the converter body shell 2, a converter bottom refractory material 4 is built on the converter bottom shell 8, the converter bottom shell 8 is detachably fixed on the converter body shell 2 through bolts, an annular gap is formed between the furnace body refractory material 3 and the converter bottom refractory material 4, and an isolation layer 6 is pasted on the vertical surface of the furnace body refractory material 3 on one side of the annular gap.

In a preferred embodiment, the isolation layer 6 is made of aluminum foil paper, the thickness of the aluminum foil paper is 0.025mm, the width of the annular gap is 30-100 mm, and the converter is filled with the special ramming joint compound 5 during primary building.

In a preferred embodiment, a gas supply and powder injection system 7 is arranged between the bottom shell 8 of the converter and the refractory material 4 at the bottom of the converter, and is used for the bottom blowing process of smelting.

In this embodiment, the aluminium foil material has higher melting point (660 ℃), low melting point organic volatile matter volatilizees gradually in the intensification in-process seam ramming material, high melting point organic matter will carbonize gradually after 300 ℃, aluminium foil paper has completely cut off the adhesion combination between furnace shaft refractory material and the ramming material, consequently when the converter stove bottom needs hot change, very easily break away from between furnace shaft refractory material and the ramming material, the stove bottom of converter is easily dismantled and is cleared up, and avoided the damage to furnace shaft refractory material, the efficiency of construction when converter stove bottom hot change has greatly been improved.

Example 2:

a converter with a replaceable converter bottom is shown in figure 1 and comprises a detachable converter bottom shell 8 and a converter body shell 2, a furnace body refractory material 3 is built on the inner side of the converter body shell 2, a converter bottom refractory material 4 is built on the converter bottom shell 8, the converter bottom shell 8 is detachably fixed on the converter body shell 2 through bolts, an annular gap is formed between the furnace body refractory material 3 and the converter bottom refractory material 4, and an isolation layer 6 is pasted on the vertical surface of the furnace body refractory material 3 on one side of the annular gap

In a preferred embodiment, the insulating layer 6 may also be a glass fiber aluminum foil cloth, a pure cotton cloth, or a carbon fiber cloth material, and also may insulate the adhesive bond between the furnace body refractory and the ramming mass, so that the converter may be easily disassembled and cleaned during the subsequent thermal replacement of the converter bottom.

Example 3:

in the embodiment, the solid material adopted by the ramming joint compound is 70 wt% of fused magnesia particles, 16 wt% of fused magnesia fine powder, 12 wt% of high-iron high-calcium sand fine powder, 5 wt% of medium-temperature asphalt fine powder, 1.2 wt% of metal aluminum powder, 1.5 wt% of silicon carbide fine powder and 1.2 wt% of solid resin, and the liquid material is 3.6 wt% of wash oil.

In a preferred embodiment, the fused magnesia particles have an MgO content of 97 wt% and a particle diameter of 3 mm; the MgO content in the fused magnesia fine powder is 97 wt%, and the particle size is 0.08 mm; the MgO content in the high-iron high-calcium sand fine powder is 85 wt%, and the Fe content₂O₃The content of (A) is 6 wt%, the content of CaO is 10 wt%, and the grain diameters of the particles are all 0.08 mm; the softening point of the medium temperature asphalt fine powder is 115 ℃, the residual carbon content is 58 percent, and the particle size is 0.8 mm; the Al content in the metal aluminum powder is 99 wt%, and the particle size is 0.08 mm; the SiC content in the silicon carbide fine powder is 98.5 percent, and the grain diameter is 0.08 mm; the solid resin is phenolic resin special for refractory materials, and the particle size is 0.12 mm; the water content in the wash oil was 0.45 wt%.

The materials are accurately measured according to the mass percentage, firstly, the solid materials are added into a mixing roll for dry mixing for 4-5 minutes, then, the liquid materials are slowly added into the mixing roll within 1-2 minutes, the mixing is continued for 10 minutes, and the pug after the mixing is finished is the ramming joint material.

The washing oil adopted by the ramming joint material in the embodiment can soften the medium-temperature asphalt fine powder and infiltrate the fused magnesia fine powder and the fused magnesia particles to play a role in wetting and bonding, and the joint material has a good ramming and compacting construction effect due to the addition of the suitable medium-temperature asphalt fine powder and the washing oil. In addition, the joint material mixed by the method is stored in a plastic sealing bag, can keep the plastic stability for a long time in a normal temperature environment, and can be normally used within 60 days.

Example 4:

a construction method for the initial building of a converter with a replaceable converter bottom comprises the following steps:

firstly, the joint material is rammed by mixing according to the steps in the embodiment 3; building a refractory material 3 on the inner side of a converter body shell 2, adhering an isolation layer on the vertical surface of the bottom of the refractory material 3 after building, building a furnace bottom refractory material 4 on a converter bottom shell 8, fixing the converter bottom shell 8 with the built furnace bottom refractory material on the converter body shell 2, and forming an annular gap between the fixed furnace bottom refractory material and the fixed furnace body refractory material; and then filling and tamping the annular gap by adopting a tamping joint material, wherein in the filling process, the tamping joint material is tamped by downwards dividing the tamping joint material into a plurality of layers of fillers, each layer of filler is controlled to be 150-200 mm, the next layer of filler is filled after tamping, and the density of the tamped tamping joint material is ensured to be more than 2.50g/cm³In the tamping process, attention must be paid so as not to damage the isolating layer attached to the vertical surface of the refractory material of the furnace body; and after the annular gap is filled, standing the converter for 0.5-1 hour, and then baking the converter, wherein the temperature is raised to 1000 ℃ from low temperature during baking, the temperature rise time is controlled to be more than 1.5 hours, and after the temperature is higher than 1000 ℃, the converter is continuously baked for 1 hour, and then the converter can be used for smelting.

In the construction method, the joint material is tamped by multiple layers of fillers, and the asphalt fine powder is gradually carbonized after high temperature to form carbon chain combination with the fused magnesia particles and the fused magnesia fine powder, so that the high-temperature strength and the high-temperature performance are good, the construction quality is ensured, the steel leakage accident is avoided, the corrosion speed of molten steel on the joint material is slowed down, the service life of the converter which is built for the first time can reach about 4500 furnaces, and the service life of the converter during the first building is greatly prolonged.

The present invention is not described in detail, but is known to those skilled in the art. Finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered in the claims of the present invention.