Spray material for simple wet spray application apparatus

Abstract

The present invention provides a spray material for a simple wet spray application apparatus, the spray material having improved conveyability and adhesion. A spray material A according to the present invention is for use in a simple wet spray application apparatus 1 comprising: a dispensing portion 11 that receives the spray material A containing a refractory material and a binder and continuously dispenses the spray material A; a water injection portion 12 that adds water B to the spray material A dispensed from the dispensing portion 11; a kneading portion 13 that kneads the water B added by the water injection portion 12 and the spray material A; and a pressure-feeding portion 14 that pressure-feeds a kneaded material C, continuously supplied from the kneading portion 13, to a spray nozzle 16 through a conveyance hose 15 by compressed air D. The particle size composition of the refractory material in the spray material A is such that coarse particles having a particle diameter of 1 mm or more and less than 3 mm are 30 mass% or less (including 0), medium particles having a particle diameter of 0.075 mm or more and less than 1 mm are 40-70 mass%, and fine particles having a particle diameter of less than 0.075 mm are 20-50 mass%. The rate of addition of the water B added at the water injection portion 12 is 20-40 mass%.

Description

Spraying Material for Simple Wet Spraying Construction Apparatus

[0001] The present invention relates to a spraying material for use in a simple wet spraying construction apparatus.

[0002] Spraying construction is performed as a means for forming or repairing linings of molten metal vessels, high-temperature furnaces, molten metal treatment apparatuses, and the like. Spraying construction is broadly classified into wet spraying construction and dry spraying construction. Among these spraying constructions, for wet spraying construction, it is common practice that a spraying material preliminarily prepared into a slurry by adding water is pressure-fed to a spraying nozzle through a conveying hose by a pressure feed pump, and a quick-setting admixture is added in the spraying nozzle or in the conveying hose before spraying (for example, Patent Documents 1 and 2). In such common wet spraying construction, a slurry-form spraying material is prepared in advance, the slurry-form spraying material is pressure-fed to the spraying nozzle by a pressure feed pump such as a squeeze pump, and further a quick-setting admixture is added in the spraying nozzle or in the conveying hose before spraying.

[0003] On the other hand, as a simple wet spraying construction, there is so-called simple wet spraying construction in which a series of steps from preparation of a slurry-form spraying material to spraying are performed by a single wet spraying construction apparatus. A simple wet spraying construction apparatus that implements this simple wet spraying construction includes a cutting-out section that receives the spraying material and continuously cuts out the same, a water injection section that adds water to the spraying material cut out from the cutting-out section, a kneading section that kneads the water added from the water injection section and the spraying material, and a pressure feed section that pressure-feeds the kneaded material continuously supplied from the kneading section to a spraying nozzle through a conveying hose by compressed air (for example, Patent Document 3).

[0004] Japanese Patent Application Laid-Open No. 2018-115082, Japanese Patent Application Laid-Open No. 2021-161004, Japanese Patent Application Laid-Open No. 2000-46479

[0005] When the present inventor conducted tests on simple wet spraying construction, it was found that due to circumstances specific to simple wet spraying construction apparatuses, such as that kneading in the kneading section is continuous and takes a short time, and pressure feeding of the spraying material relies on compressed air, there are problems in the conveyability of the spraying material in the conveying hose, and also problems in the adhesion of the spraying material to the work surface.

[0006] Therefore, the problem that the present invention aims to solve is to improve the transportability and adhesion of the spray material in simple wet spray application, and more specifically, to provide a spray material for a simple wet spray application apparatus that has improved transportability and adhesion.

[0007] As a result of repeated tests of a simple wet spray application method, the inventors of this invention have found that in order to improve the transportability and adhesion of the spray material in a simple wet spray application method, it is essential to control the particle size composition of the fire-resistant material in the spray material and to control the amount of water added to the spray material.

[0008] In other words, according to one aspect of the present invention, the following spray material for a simple wet spray application apparatus is provided. A spray material for a simple wet spray application apparatus, which is used in a simple wet spray application apparatus having: a cutting section that receives a spray material containing a fire-resistant material and a binder and cuts out the spray material continuously; a water injection section that adds water to the spray material cut out from the cutting section; a mixing section that mixes the water added from the water injection section with the spray material; and a pumping section that pumps the mixture continuously supplied from the mixing section to a spray nozzle through a transport hose using compressed air, wherein the spray material contains a fire-resistant material and a binder, and the particle size composition of the fire-resistant material in the spray material is 30% by mass or less (including 0) of coarse particles with a particle size of 1 mm or more and less than 3 mm, 40% by mass or more and 70% by mass or less of medium particles with a particle size of 0.075 mm or more and less than 1 mm, and 20% by mass or more and 50% by mass or less of fine particles with a particle size of less than 0.075 mm. A spray material for a simple wet spray application apparatus, wherein the water added at the water injection section is 20% to 40% by mass on the outside, relative to 100% by mass of the total spray material.

[0009] According to the present invention, it is possible to provide a spray material for a simple wet spray application apparatus that has improved transportability and adhesion, thereby improving the transportability and adhesion of the spray material in simple wet spray application.

[0010] A conceptual diagram showing the configuration of a simple wet-type spray application system.

[0011] First, the device configuration of the simple wet spray application apparatus using the spray material of the present invention will be described. Figure 1 is a conceptual diagram showing the device configuration of the simple wet spray application apparatus. As shown in the figure, the simple wet spray application apparatus 1 has a cutting section 11 that receives the spray material A and cuts out the spray material A continuously, a water injection section 12 that adds water B to the spray material A cut out from the cutting section 11, a mixing section 13 that mixes the water B added from the water injection section 12 with the spray material A, and a pumping section 14 that pumps the mixed material C continuously supplied from the mixing section 13 through a transport hose 15 to the spray nozzle 16 using compressed air D.

[0012] The spray material A is supplied from an external source and contains a refractory material and a binder. The first technical feature of the present invention is that, in order to solve the above problems, the particle size composition of the refractory material in the spray material A is controlled. Specifically, in the present invention, the particle size composition of the refractory material in the spray material A is 30% by mass or less (including 0) of coarse particles with a particle size of 1 mm or more and less than 3 mm, 40% by mass or more and 70% by mass of medium particles with a particle size of 0.075 mm or more and less than 1 mm, and 20% by mass or more and 50% by mass of fine particles with a particle size of less than 0.075 mm. If the proportion of coarse particles exceeds 30% by mass, the proportion of coarse particles in the compound C becomes excessive, making segregation (hereinafter simply referred to as "segregation") of the particles in the compound C more likely to occur, resulting in a decrease in transportability. Furthermore, a decrease in transportability also leads to a decrease in adhesion. If the proportion of medium-sized particles is less than 40% by mass, the proportion of coarse or fine particles becomes relatively high, making segregation more likely, and the back pressure applied to the pumping section 14 increases, reducing transportability and adhesion. Similarly, if the proportion of medium-sized particles exceeds 70% by mass, segregation is also more likely, reducing transportability and adhesion. If the proportion of fine particles is less than 20% by mass, the cohesiveness of the mixture C at the moment of adhesion to the workpiece is insufficient, resulting in reduced adhesion. On the other hand, if the proportion of fine particles exceeds 50% by mass, the cohesiveness of the mixture C becomes too strong, increasing the back pressure applied to the pumping section 14, thus reducing transportability and adhesion.

[0013] In this invention, the particle size of the refractory material refers to the size of the sieve opening when the refractory material is separated by sieving. For example, a refractory material with a particle size of less than 1 mm is a refractory material that can pass through a sieve with a 1 mm opening, and a refractory material with a particle size of 1 mm or more is a refractory material that cannot pass through a sieve with a 1 mm opening.

[0014] The second technical feature of the present invention lies in controlling the addition rate of water B to the spray material A. Specifically, the second technical feature of the present invention is that the addition rate of water B added in the water injection section 12 is set to 20% by mass or more and 40% by mass or less. If the addition rate of water B is less than 20% by mass, the viscosity of the kneaded material C is high and the back pressure applied to the pumping section 14 is high, so the transportability and adhesion are reduced. On the other hand, if the addition rate of water B exceeds 40% by mass, the amount of water in the kneaded material C is excessive and the cohesiveness is weakened, so the adhesion is reduced.

[0015] Here, the improvement in transportability and adhesion due to each of the above technical features of the present invention is particularly evident when the length of the transport hose 15 is 10 m or more. This is because the problems of transportability and adhesion become particularly apparent when the length of the transport hose 15 is 10 m or more.

[0016] The technical features of the present invention are as described above. The types and mixing ratios of the fire-resistant material and binder constituting the spray material A are not particularly limited and may be the same as those of conventional spray materials. For example, various fire-resistant materials such as magnesia, alumina, and silica can be used as the fire-resistant raw material, and various binders such as phosphates, silicates, and cement can be used as the binder. Furthermore, the mixing ratio of the fire-resistant material and binder may be the same as that of a general spray material. In addition, the spray material of the present invention may contain various additives other than the fire-resistant material and binder described above, such as dispersants, hardening modifiers, fibers, and thickeners. The content of these additives may also be the same as that of a general spray material.

[0017] Table 1 shows the composition of the spray materials for the embodiments and comparative examples of the present invention, as well as the evaluation results of the transportability and adhesion of the spray materials for each example. Transportability and adhesion were evaluated by conducting a spray test using the simple wet spray application apparatus 1 shown in Figure 1. In the spray test of the spray materials for each example, the amount of water added at the water injection section 12 is as shown in Table 1. The length of the transport hose 15 was set to 10 m. Transportability was evaluated by the discharge condition of the mixture C (a mixture of spray material A and water B transported by compressed air D) discharged from the spray nozzle 16 during the spray test. Specifically, if there was no pulsation of the mixture C and the discharge condition was stable, it was evaluated as ○ (excellent), if pulsation occurred several times it was evaluated as △ (good), and if pulsation occurred frequently it was evaluated as × (poor), with ○ or △ being considered a pass. Adhesion was evaluated by the adhesion rate of the mixture C to the application surface. Specifically, a bonding rate of 80% or more was evaluated as ○ (Excellent), 60% or more but less than 80% as △ (Good), and less than 60% as × (Poor), with ○ or △ being considered a passing grade.

[0018]

[0019] Examples 1 and 2 show variations in the proportion of coarse particles in the particle size composition of the refractory material in sprayed material A. Both examples fall within the scope of the present invention, and both transportability and adhesion are at an acceptable level. In contrast, Comparative Example 1 is an example in which the proportion of coarse particles exceeds the upper limit of the present invention, resulting in decreased transportability and, consequently, decreased adhesion.

[0020] Examples 3 and 4 are examples in which the proportion of medium-sized particles in the particle size composition of the refractory material in sprayed material A was changed, but both were within the scope of the present invention, and both the transportability and adhesion were at an acceptable level. In contrast, Comparative Example 2 is an example in which the proportion of medium-sized particles was below the lower limit of the present invention, resulting in decreased transportability and consequently decreased adhesion. Comparative Example 3 is an example in which the proportion of medium-sized particles was above the upper limit of the present invention, resulting in decreased transportability and consequently decreased adhesion.

[0021] Examples 5 and 6 show variations in the particle size composition of the refractory material in sprayed material A, specifically in which the proportion of fine particles was changed. Both examples were within the scope of the present invention, and both transportability and adhesion were at an acceptable level. In contrast, Comparative Example 4 was an example where the proportion of fine particles fell below the lower limit of the present invention, resulting in reduced adhesion. Comparative Example 5 was an example where the proportion of fine particles exceeded the upper limit of the present invention, resulting in reduced transportability and adhesion.

[0022] Examples 7 and 8 show variations in the water addition rate, but both were within the scope of the present invention, and both transportability and adhesion were at an acceptable level. In contrast, Comparative Example 6 is an example where the water addition rate was below the lower limit of the present invention, resulting in decreased transportability and adhesion. Comparative Example 7 is an example where the water addition rate exceeded the upper limit of the present invention, resulting in decreased adhesion.

[0023] Examples 9 and 10 are examples in which the type of binder was changed, but both were within the scope of the present invention, and both transportability and adhesion were at an acceptable level. From the comparison between Examples 9 and 10, it can be said that it is preferable to use one or more types selected from phosphates and silicates as the binder.

[0024] 1. Simple wet spray application apparatus 11. Cutting section 12. Water injection section 13. Mixing section 14. Pressure feeding section 15. Conveying hose 16. Spray nozzle A. Spray material B. Water C. Mixed material D. Compressed air

Claims

1. A spray material for a simple wet spray application apparatus, which is used in a simple wet spray application apparatus having: an cutting section that receives a spray material containing a fire-resistant material and a binder and cuts the spray material continuously; a water injection section that adds water to the spray material cut from the cutting section; a mixing section that mixes the water added from the water injection section with the spray material; and a pumping section that pumps the mixture continuously supplied from the mixing section to a spray nozzle through a transport hose using compressed air, wherein the spray material contains a fire-resistant material and a binder, and the particle size composition of the fire-resistant material in the spray material is 30% by mass or less (including 0) of coarse particles with a particle size of 1 mm or more and less than 3 mm, 40% by mass or more and 70% by mass or less of medium particles with a particle size of 0.075 mm or more and less than 1 mm, and 20% by mass or more and 50% by mass or less of fine particles with a particle size of less than 0.075 mm. A spray material for a simple wet spray application apparatus, wherein the water added at the water injection section is 20% to 40% by mass on the outside, relative to 100% by mass of the total spray material.

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