Spray nozzle and spray method

Abstract

To provide a spray nozzle capable of efficiently spraying a spray material while uniformly controlling the concentration distribution of the spray material to be discharged, and a spray method.SOLUTION: A spray nozzle for spraying slurry spray material comprises a cylinder with a flow path formed inside, and a plurality of independent protrusions that protrude from the inner peripheral surface of the cylinder toward the inside of the cylinder. The plurality of protrusions are arranged spirally on the inner peripheral surface of the cylinder.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a spraying method for spraying a spraying material such as mortar onto a construction target such as a concrete structure, and to a spraying nozzle used in the spraying method. [Background technology]

[0002] In repair and reinforcement work on concrete structures, a spraying method is sometimes used in which a spraying material such as mortar is sprayed onto the work surface. Specifically, in the mortar spraying method, mortar prepared from cement, aggregate, water, etc. is pressure-fed by a pump or the like, and the mortar is discharged from a spray nozzle attached to the tip of a hose or the like, thereby spraying the mortar onto the work surface of the concrete structure or the like (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-98648 Summary of the Invention [Problem to be solved by the invention]

[0004] In this type of mortar spraying method, it was thought that in order to apply a thick layer of mortar to the work surface, it was necessary to increase the mortar discharge speed. However, with conventional spray nozzles, simply increasing the mortar discharge speed resulted in a larger amount of mortar being discharged from near the center of the nozzle than the amount being discharged to the periphery, resulting in a conical mortar concentration distribution biased toward the center of the nozzle, resulting in poor evenness of the mortar sprayed onto the work surface. Furthermore, if the material discharged from the nozzle is biased toward the center, the material being discharged from near the center itself will blow away the material adhering to the work surface, resulting in the problem of inefficient thick application.

[0005] An object of the present invention is to provide a spray nozzle and a spraying method that can efficiently spray a spray material while controlling the concentration distribution of the spray material being discharged as uniformly as possible. [Means for solving the problem]

[0006] One aspect of the present invention is A spray nozzle for spraying a slurry-like spray material, a cylindrical body having a flow path formed therein; a plurality of independent protrusions protruding from an inner circumferential surface of the cylindrical body toward the inside of the cylindrical body; The spray nozzle is characterized in that the plurality of protrusions are arranged along a spiral on the inner circumferential surface of the cylindrical body.

[0007] With a spray nozzle of this configuration, the pressure-fed spray material collides with the multiple independent protrusions as it passes through the cylinder, changing its flow direction and reducing the speed difference between the center and its periphery, resulting in a uniform concentration of the spray material discharged from the spray nozzle. This makes it possible to spray the spray material to a uniform thickness onto the construction surface.

[0008] The multiple protrusions may be arranged at equal intervals on the inner surface of the cylinder when viewed from the center line direction of the cylinder, and preferably include three protrusions arranged at intervals of 120° on the inner surface of the cylinder when viewed from the center line direction of the cylinder.

[0009] This configuration allows the spray material to be sprayed onto the construction surface with a more uniform thickness.

[0010] The ratio (r2 / D) of the height r2 of the protrusion to the inner diameter D of the cylindrical body can be set to be equal to or greater than 0.3 and equal to or less than 0.55.

[0011] This configuration allows the spray material to be sprayed onto the construction surface with a more uniform thickness.

[0012] Each of the protrusions preferably has a sloped portion whose cross-sectional area increases toward the downstream side of the flow path.

[0013] With this configuration, when the spray material flowing in the axial direction of the cylinder collides with multiple protrusions, the flow direction of the spray material is changed with less resistance, making the concentration more uniform and effective.

[0014] The inclined portion preferably has a conical shape, and the center line of the cone is disposed so as to be substantially parallel to the center of the cylinder.

[0015] With this configuration, when the spray material flowing in the axial direction of the cylinder collides with the multiple protrusions, the flow direction is changed with less resistance, making the concentration more uniform and effective.

[0016] Furthermore, a spraying method as one aspect of the present invention involves spraying a spray material using any of the spray nozzles described above.

[0017] According to the spraying method having such a configuration, it is possible to spray the spray material uniformly onto the construction surface. [Effects of the Invention]

[0018] As described above, the present invention provides a spray nozzle and a spraying method that can efficiently spray a spray material onto a construction surface with a uniform thickness. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a perspective view, partly in section, showing a spray nozzle according to one embodiment. [Figure 2] FIG. 2 is an axial cross-sectional view showing a spray nozzle according to one embodiment. [Figure 3] FIG. 3 is a side view of the spray nozzle of FIG. 2 as seen from the upstream side in the axial direction. [Figure 4] FIG. 4 is an axial cross-sectional view showing a spray nozzle according to another embodiment. [Figure 5] FIG. 5 is an axial cross-sectional view showing a spray nozzle according to another embodiment. [Figure 6] FIG. 6 is an axial cross-sectional view showing a spray nozzle of one embodiment used in the simulation. [Figure 7] FIG. 7 shows the results of a simulation using the spray nozzle of Example 5, and is a graph showing the distribution of the spray material at a predetermined distance from the nozzle outlet. [Figure 8] FIG. 8 shows the results of a simulation using the spray nozzle of Example 10, and is a graph showing the distribution of the spray material at a predetermined distance from the nozzle outlet. [Figure 9] FIG. 9 shows the results of a simulation using the spray nozzle of Example 11, and is a graph showing the distribution of the spray material at a predetermined distance from the nozzle outlet. [Figure 10] FIG. 10 shows the results of a simulation using a spray nozzle of a comparative example, and is a graph showing the distribution of the spray material at a predetermined distance from the nozzle outlet. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, a spray nozzle according to a first embodiment of the present invention will be described with reference to the accompanying drawings.

[0021] The spray nozzle according to this embodiment is suitable for use in a spraying method using mortar as the spraying material. Specifically, the spray nozzle is attached to the tip of a hose for use in a so-called wet mortar spraying method in which cement, aggregate, water, etc. are mixed to prepare mortar, and the mortar is then pressurized by a pump or the like and pumped through a hose to be sprayed onto a construction surface such as a concrete structure.

[0022] 1 and 2, the spray nozzle 1 according to this embodiment comprises, in order from the upstream side in the direction of mortar flow, a connecting section 10 that is joined to the tip of a hose (not shown) through which mortar is pumped, a protrusion installation section (cylinder) 20 that extends downstream of the connecting section 10, a tapered section 30 that extends downstream of the protrusion installation section 20, and a tip section 40 that extends downstream of the tapered section. Mortar flows into the spray nozzle 1 via the tip of a hose or the like that is connected to the connecting section, passes through the protrusion installation section 20, the tapered section 30, and the tip section 40, and is then discharged from the tip opening of the tip section 40 toward the construction surface.

[0023] In the spray nozzle 1 according to this embodiment, the connecting portion 10, the protrusion mounting portion 20, the tapered portion 30, and the tip portion 40 are each formed in a cylindrical shape and have a flow path through which mortar can flow. The flow path has a circular cross section perpendicular to the axial direction, except for the region provided with the protrusions described below. Note that the connecting portion 10 is configured so that a connecting jig attached to the tip of a hose can be inserted inside the connecting portion, and the flow path at the tip of the hose and the flow path in the protrusion mounting portion 20 are smoothly connected.

[0024] In the following description, the direction along an imaginary center line passing through the center of the spray nozzle will be referred to as the axial direction, the direction intersecting the center line in a plan view seen from the axial direction will be referred to as the radial direction, and the direction circumferentially around the center line in the plan view will be referred to as the circumferential direction. Furthermore, the upstream side in the direction of mortar flow will sometimes be referred to simply as the upstream side, and the downstream side (discharge side) in the direction of mortar flow will sometimes be referred to simply as the downstream side.

[0025] 1 and 2, the spray nozzle 1 according to this embodiment has three protrusions 21 at positions of the flow path corresponding to the protrusion installation portion 20, specifically, from the upstream side, a first protrusion 21a, a second protrusion 21b, and a third protrusion 21c. Each protrusion 21 has a shape that protrudes radially inward from the inner circumferential surface of the cylindrical protrusion installation portion 20 that forms the flow path for mortar.

[0026] In this embodiment, the three protrusions 21 are independent of one another; in other words, the periphery of each protrusion 21 reaches the inner circumferential surface of the protrusion installation portion 20, and the protrusions 21 are spaced apart from one another. The three protrusions 21 in this embodiment are arranged along a spiral on the inner circumferential surface of the cylindrical protrusion installation portion (cylinder) 20. That is, the three protrusions 21 are arranged at positions spaced apart in the axial direction and also spaced apart in the circumferential direction. Specifically, as shown in FIG. 3, the three protrusions 21 are arranged at positions shifted 120° in the circumferential direction around the center line of the spray nozzle when viewed from the upstream side in the axial direction. That is, the first protrusion 21a, which is located most upstream, is positioned in the 2 o'clock direction (upper right in Figure 3) based on the center line of the spray nozzle, the second protrusion 21b, which is positioned next to the downstream side of the first protrusion 21a, is also positioned in the 6 o'clock direction (lower in Figure 3), and the third protrusion 21c, which is positioned next to the downstream side of the second protrusion 21b, is also positioned in the 10 o'clock direction (upper left in Figure 3).

[0027] 2, each protrusion 21 has a first inclined surface 211 facing upstream and a second inclined surface 212 facing downstream. In this embodiment, the first inclined surface 211 and the second inclined surface 212 are each conical with a center line substantially parallel to the axial direction of the protrusion installation portion 20, and each center line is located on the inner circumferential surface of the protrusion installation portion 20. In other words, the first inclined surface 211 and the second inclined surface 212 of each protrusion 21 are in a state where a portion of the cone protrudes inward from the inner circumferential surface of the protrusion installation portion 20, blocking part of the flow path. That is, in this embodiment, the first inclined surface 211 functions as an inclined portion whose cross-sectional area increases toward the downstream side of the flow path. Note that the cross-sectional area here means the area of ​​the region surrounded by the outer contour line and the extension line (arc) of the inner circumferential surface in the radial cross section of the protrusion, and is included in that area even if the inside of the cross section (inside of the protrusion) is hollow.

[0028] With the above configuration, the radial cross-sectional area of ​​each protrusion 21 increases toward the downstream side in the upstream portion (portion corresponding to the first inclined surface 211) of the protrusion 21. Conversely, the radial cross-sectional area of ​​each protrusion 21 decreases toward the downstream side in the downstream portion (portion corresponding to the second inclined surface 212) of the protrusion 21.

[0029] The height r2 of the protrusion 21, i.e., the height of the protrusion 21 in the radial direction from the inner peripheral surface in the axial cross section of the protrusion installation portion 20, is configured to be approximately the same as the flow path radius of the protrusion installation portion 20. Specifically, the ratio (r2 / D) of the height r2 of the protrusion 21 to the inner diameter D of the flow path is preferably 0.35 or more and 0.55 or less. With this configuration, the effect of the protrusion 21 is more easily exerted. In this embodiment, the height of the protrusion 21 is the radius of the base of the cone that constitutes the first inclined surface 211 and the second inclined surface 212.

[0030] 2, when viewed in an axial cross section passing through the center of the protrusion 21, the ratio (r2 / d1) of the height r2 of the protrusion 21 to the axial length d1 from the upstream tip to the downstream tip of the protrusion 21 is preferably 0.4 or more and 2.5 or less. With this configuration, the effect of providing the protrusion 21 is more easily exhibited.

[0031] Furthermore, it is preferable that the ratio (y / r2) of the distance y between adjacent protrusions 21, for example, the distance y from the upstream end of a first protrusion 21a to the upstream end of the adjacent second protrusion 21b, to the height r2 of the protrusion 21 from the inner circumferential surface, is 1 or more and 3.5 or less. With this configuration, the effect of providing the protrusions 21 is more easily exhibited.

[0032] In the specific shape of the protrusion 21 in this embodiment, the apex angle of the cone that forms the first inclined surface 211 is smaller than the apex angle of the cone that forms the second inclined surface 212. In other words, the shape is such that the slope on the upstream side is gentler than the slope on the downstream side. In addition, the portion between the first inclined surface 211 and the second inclined surface 212 is configured as a part of a cylinder with the same radial cross section along the axial direction.

[0033] By providing the protrusion installation portion 20 having such a configuration, the mortar first collides with the first protrusion 21a when passing through the protrusion installation portion 20. The flow direction of the mortar that collides with the first protrusion 21a is changed by the first inclined surface 211, and specifically, the mortar has a velocity component that spreads radially from the first inclined surface 211 when viewed in the axial direction.

[0034] The mortar that has passed through the first protruding portion 21a then collides with the second protruding portion 21b and the third protruding portion 21c in sequence, and passes through the protrusion mounting portion 20 while being subjected to the same action as that of the first protruding portion from each of the protruding portions. As described above, the first protruding portion 21a, the second protruding portion 21b, and the third protruding portion 21c are arranged along a spiral on the inner circumferential surface of the protrusion mounting portion 20, and therefore the mortar that has passed through the protrusion mounting portion 20 will have a velocity component in the spiral direction as a whole.

[0035] That is, the mortar that has passed through the protrusion installation section 20 has a uniform flow velocity distribution within the flow path, and also has a velocity component in the spiral direction. As a result, the mortar discharged from the spray nozzle according to this embodiment has a uniform mortar concentration from the center to the outside, making it possible to apply mortar of a uniform thickness to the application surface.

[0036] In addition, each protrusion 21 has an inclined portion whose cross-sectional area increases toward the downstream side, which has the effect of reducing the resistance acting on the mortar passing through the protrusion installation portion 20 and preventing the pressure loss of the mortar from increasing.

[0037] The tapered section 30, located downstream of the protrusion installation section 20, is continuous with the protrusion installation section 20 and has a tapered shape in which the cross-sectional area of ​​the flow path decreases toward the downstream side. Specifically, in the axial cross section shown in Figure 2, the angle formed by the opposing inner circumferential surfaces is preferably 5 to 15 degrees.

[0038] Furthermore, the spray nozzle of this embodiment is provided with a tip section 40 downstream of the tapered section 30, the inner diameter of which is constant along the axial direction. The inner diameter of this tip section 40 is preferably in the range of 0.5 to 0.7 times the inner diameter of the protrusion installation section 20. The tip of this tip section 40 serves as the outlet from which the spray material is discharged. The ratio (x / D) of the distance x from the protrusion 21 located at the most downstream position to the outlet to the inner diameter D of the protrusion installation section 20 is preferably in the range of 5 or more and 10 or less.

[0039] The shape of the protrusion is not limited to the shapes in the above embodiment, and may be any shape, such as a sphere, a spheroid (a prolate spheroid), a pyramid, a cone, or any shape similar to these, or a combination of some or more of these shapes.

[0040] For example, the protrusion in the present invention may have a spheroid shape (a roughly spherical shape with a slightly shorter axial diameter) as shown in Fig. 4. Also, as shown in Fig. 5, the protrusion in the present invention may have a triangular pyramid shape with the base facing downstream and the apex facing upstream.

[0041] One embodiment of the spraying method is a method of spraying a spray material onto a construction surface of a construction object using a spray nozzle having the above-described configuration. Specifically, a so-called wet spraying method can be employed, which includes a material preparation step of preparing the spray material, a pressure-transport step of pressurizing the prepared spray material with a pump or the like and pressure-transporting it to the construction site through a pressure-transport path such as a hose, and a spraying step of discharging the spray material through a spray nozzle having the above-described configuration attached to the tip of the pressure-transport path and spraying it onto the construction surface of the construction object, such as a concrete structure.

[0042] In another embodiment, a so-called dry spraying method can be adopted, which includes a powder material preparation process in which materials other than water are mixed to prepare a powder material, a powder material pressure transfer process in which the powder material is pressure transferred to the construction site via a pressure transfer path such as a hose, a water pressure transfer process in which water is pressure transferred to the construction site via a pressure transfer path separate from the powder material, a mixing process in which the powder material and water are mixed just before the spray nozzle, and a spraying process in which the mixed spray material is sprayed onto the construction surface via the spray nozzle of the above configuration.

[0043] As the spraying material, slurry-like spraying materials containing inorganic materials such as various cements, gypsum, fine aggregates, coarse aggregates, etc., or organic materials such as fibers, wood materials, polymers, etc. can be suitably used, and mortar can be suitably used in particular.

[0044] The equipment used in each step of the spraying method can be any equipment known in this field except for the spray nozzle, and a detailed description thereof will be omitted.

[0045] Next, the results of evaluating the spray performance of spray nozzles according to embodiments of the present invention using a simulation will be described. The spray nozzles used in the simulation were one with a protrusion in the shape shown in Figures 1 to 3 (hereinafter also referred to as a top-shaped) as described above, one with an ellipsoidal protrusion shown in Figure 4, and one with a triangular pyramid-shaped protrusion shown in Figure 5. For the spray nozzle with a top-shaped protrusion, the dimensions of each part shown in Figure 6 were evaluated using the values ​​shown in Table 1 below, and these were designated Examples 1 to 9. On the other hand, as a comparative example, a spray nozzle in which all of the protruding portions were removed from the spray nozzle of this embodiment shown in FIGS. 1 to 3 was used and evaluated.

[0046] [Table 1]

[0047] The results of the simulation are as shown in Table 1. The results of the simulation show that the average particle velocity at the nozzle outlet is lower for all of the spray nozzles of Examples 1 to 9 compared to the spray nozzle of the comparative example that does not have a protrusion.

[0048] Furthermore, the particle distributions calculated for the spray nozzles of Example 5 (top-shaped), Example 10 (ellipsoidal), Example 11 (triangular pyramid), and the comparative example (without protrusions) in a plane perpendicular to the axial direction at 0.2 m, 0.4 m, and 0.6 m from the nozzle outlet are shown in Figures 7 to 10. For the spray nozzles of Examples 5, 10, and 11, it can be seen that the particles discharged from the nozzle outlet are uniformly distributed in a plane perpendicular to the axial direction, as shown in Figures 7, 8, and 9. In contrast, for the spray nozzle of the comparative example, which does not have protrusions, it can be seen that the particles discharged from the nozzle outlet are distributed unevenly toward the center, as shown in Figure 10.

[0049] In this way, the spray nozzle of this embodiment reduces the average particle velocity of the spray material discharged from the nozzle and discharges it with a concentration distribution that spreads evenly over the application surface, making it possible to efficiently apply a thick layer of spray material to the application surface without blowing it away.

[0050] The spray nozzle and spray method according to the present invention are not limited to the above-described embodiment, and it goes without saying that various modifications can be made within the scope of the gist of the present invention.

[0051] For example, the spray nozzle in the above embodiment has been described as having the connecting portion 10, protrusion mounting portion 20, tapered portion 30, and tip portion 40 integrally formed from a single continuous member, but the present invention is not limited to such a configuration, and it is also possible to combine multiple members to form a spray nozzle of the above configuration.

[0052] Furthermore, in the above embodiment, the spray nozzle is described as having three protrusions, but the present invention is not limited to this configuration, and the spray nozzle may have four or more protrusions. [Explanation of symbols]

[0053] 1... spray nozzle, 10... connecting portion, 20... protrusion installation portion, 30... tapered portion, 40... tip portion, 21... protrusion portion

Claims

1. A spray nozzle for spraying a slurry-like spray material, a cylindrical body having a flow path formed therein; a plurality of independent protrusions protruding from an inner circumferential surface of the cylindrical body toward the inside of the cylindrical body; the plurality of protrusions are arranged along a spiral on the inner circumferential surface of the cylindrical body, The spray nozzle, wherein the plurality of protrusions include three protrusions arranged at intervals of 120° on the inner circumferential surface of the cylindrical body when viewed in the direction of the center line of the cylindrical body.

2. The spray nozzle according to claim 1 , wherein the plurality of protrusions are arranged at equal intervals on the inner circumferential surface of the cylindrical body when viewed in the direction of the center line of the cylindrical body.

3. 3. The spray nozzle according to claim 1, wherein a ratio (r2 / D) of a height r2 of said protrusion to an inner diameter D of said cylindrical body is 0.35 or more and 0.55 or less.

4. 4. The spray nozzle according to claim 1, wherein each of said protrusions has an inclined portion whose cross-sectional area increases toward the downstream side of said flow path.

5. 5. The spray nozzle according to claim 4, wherein the inclined portion has a conical shape, and the center line of the cone is disposed so as to be substantially parallel to the center line of the cylindrical body.

6. A spraying method comprising spraying a spray material using the spray nozzle according to any one of claims 1 to 5.

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