Nozzle, and spraying method

Abstract

To provide a nozzle and a spraying method capable of efficiently reducing the speed of emitting a jet of a spraying material jetted from a nozzle.SOLUTION: A nozzle according to the present invention is the nozzle of a jet machine that emits a jet of a spray material mixed with a powder material containing cement and a liquid material containing water through a flow path. The flow path has a curved part curved and a repulsive modulus of elasticity of the curved part on a flow path side is 0.8 or less. A spraying method according to the present invention also includes a step of emitting a jet of the spray material from the nozzle to spray the spray material onto an object.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a nozzle and a spraying method. [Background technology]

[0002] BACKGROUND ART Conventionally, a spraying method in which a spraying material such as concrete or mortar is sprayed has been widely used for the purpose of preventing collapse of excavated surfaces and suppressing weathering of rock slopes in construction work for excavated tunnels, underground spaces, etc.

[0003] Such spraying methods are known to be classified into dry and wet methods. The dry method involves pumping a dry powder material with compressed air, mixing the dry powder material with a liquid material in a spray nozzle, and spraying the mixture with high-pressure compressed air. The wet method involves adding a liquid material to the powder material and mixing them in a mixer or the like, pumping the mixture with a pressure pump, and then discharging the mixture from the spray nozzle with compressed air introduced into the nozzle, thereby spraying the mixture at high pressure.

[0004] For example, Patent Document 1 discloses a dry construction method in which a powder material containing cement and a liquid material containing water are separately supplied to a spraying nozzle, the powder material and the liquid material are mixed inside the spraying nozzle to form a spray material, and the spray material is then sprayed together with gas onto the target object. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-168224 Summary of the Invention [Problem to be solved by the invention]

[0006] In spraying methods, including both dry and wet methods, the spray material is discharged at high pressure from a spray nozzle to ensure good adhesion between the spray material and the target and to pack the spray material densely. In dry spraying methods, the dried powder material is pumped using high-pressure compressed air to prevent clogging of the flow path due to settling of the dried powder material. However, because the spray material discharged at high pressure from the spray nozzle has a high discharge speed, if the distance between the nozzle and the target becomes short, the spray material sprayed onto the target is blown away by the spray material discharged from the nozzle, resulting in a problem of reduced workability.

[0007] Possible ways to solve this problem include, for example, increasing the nozzle tip diameter or slowing the spray material discharge speed. However, increasing the nozzle tip diameter makes it easier for the powder material and liquid material that make up the spray material to separate within the nozzle, which can lead to dripping from the nozzle tip and the risk of consuming more spray material than necessary. Therefore, there is a need for a technology that prevents the spray material from being blown away by slowing down the spray material discharge speed, and there is a need for a nozzle that can efficiently slow down the spray material discharge speed.

[0008] The present invention was made in consideration of this situation, and its objective is to provide a nozzle and a spraying method that can efficiently reduce the spraying speed of the sprayed material sprayed from the nozzle. [Means for solving the problem]

[0009] The nozzle of the present invention is a nozzle of a sprayer that sprays a spray material mixed with a powder material containing cement and a liquid material containing water through a flow path, wherein the flow path has a curved bend and the rebound resilience modulus of the bend on the flow path side is 0.8 or less.

[0010] The nozzle of the present invention has a curved bend in the flow path, and the rebound elasticity modulus on the flow path side of the bend is 0.8 or less, so that the spray material can be collided with the bend to slow down its speed, thereby efficiently reducing the spray speed of the spray material.

[0011] In the nozzle according to the present invention, the flow path may be curved at the bent portion at an angle of 15 degrees or more and 90 degrees or less.

[0012] With this configuration, the nozzle according to the present invention can more reliably reduce the speed of the spray material at the bent portion.

[0013] In the nozzle according to the present invention, the flow path at the bent portion may be curved in an arc shape, and the radius of the arc of the curved flow path at the bent portion may be 30 mm or more and 160 mm or less.

[0014] With this configuration, the nozzle according to the present invention can more reliably reduce the speed of the spray material at the bent portion.

[0015] The nozzle according to the present invention may have a tapered portion downstream of the bent portion, in which the diameter of the flow path gradually decreases toward the downstream side of the flow path.

[0016] With this configuration, the nozzle according to the present invention can suppress separation of the powder material and liquid material that make up the spray material inside the nozzle, and can suppress dripping from the nozzle tip.

[0017] The spraying method of the present invention is a spraying method in which a spray material mixed with a powder material containing cement and a liquid material containing water is sprayed onto an object using a nozzle of a spray machine that sprays the spray material through a flow path, wherein the nozzle has a bent portion where the flow path is curved, and the rebound elasticity modulus of the bent portion on the flow path side is 0.8 or less, and the method includes a step of spraying the spray material from the nozzle onto the object.

[0018] In the spraying method according to the present invention, the nozzle has a bent portion where the flow path is curved, and the flow path side of the bent portion has a resilience modulus of 0.8 or less, so that the spraying material is caused to collide with the bent portion and its speed is reduced, thereby efficiently reducing the spraying speed of the spraying material, and as a result, the spraying material is prevented from being blown away. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a nozzle and a spraying method that can efficiently reduce the spraying speed of the spraying material sprayed from the nozzle. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a side view of a nozzle 1 according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, the nozzle 1 and the spraying method according to this embodiment will be described with reference to the drawings. In the following drawings, the same or corresponding parts are given the same reference characters, and their description will not be repeated.

[0022] <Nozzle> 1 is a side view of a nozzle 1 according to one embodiment of the present invention. The nozzle 1 is a nozzle of a sprayer that sprays a spraying material, which is a mixture of a powder material containing cement and a liquid material containing water, through a flow path, and is attached to the tip of a nozzle liner 5 of the sprayer.

[0023] Nozzle 1 has a flow path through which the spray material is pressure-fed together with compressed air and is sprayed from an ejection port (the downstream end of extension 4 in the direction in which the spray material flows, as described below). Nozzle 1 has a bent section 2 that curves the flow path, a tapered section 3 attached to bent section 2, and an extension 4 attached to tapered section 3.

[0024] The bend 2 is attached to the downstream tip of the nozzle liner 5. The angle of the bend 2 is the angle at which the flow path downstream of the bend 2 changes relative to the flow path upstream of the bend 2, and from the viewpoint of more reliably reducing the speed of the spraying material at the bend 2, it is preferably 15 degrees or more and 90 degrees or less, and more preferably 30 degrees or more and 90 degrees or less.

[0025] The cross-sectional shape of the flow channel at the bend 2, perpendicular to the flow direction, is circular. The diameter of the flow channel is preferably 20 mm or more and 60 mm or less, and more preferably 25 mm or more and 50 mm or less, from the viewpoint of more reliably reducing the speed of the spraying material at the bend 2. In this specification, the diameter of the flow channel refers to the linear distance between both ends of the flow channel, passing through the center of the flow channel, in a cross section perpendicular to the direction in which the spraying material flows.

[0026] The flow path of the bend 2 is curved in an arc shape, and the radius of the arc of the curved flow path at the bend 2 is preferably 30 mm or more and 160 mm or less, and more preferably 30 mm or more and 120 mm or less, from the viewpoint of more reliably reducing the speed of the spraying material at the bend 2. In this specification, the radius of the arc of the curved flow path refers to the radius of curvature of the arc that passes through the center of the flow path at the bend 2.

[0027] The rebound resilience of the flow path side of the bend 2 is 0.8 or less, and from the viewpoint of more reliably reducing the spray speed of the spray material, it is preferably 0.75 or less, more preferably 0.70 or less. Furthermore, from the viewpoint of reliably spraying the spray material sprayed from the nozzle, the rebound resilience is preferably 0.2 or more, more preferably 0.35 or more. The rebound resilience is determined by the pendulum test of JIS K 6255:2013.

[0028] The tapered section 3 is attached to the downstream end of the bent section 2. The tapered section 3 is formed so that the diameter of the flow path of the spraying material gradually decreases toward the downstream side of the flow path.

[0029] The cross-sectional shape of the flow path in tapered section 3 is circular, similar to the shape of the flow path in bent section 2. The diameter of the flow path at the upstream end of tapered section 3 (i.e., the maximum diameter of the flow path) is preferably 20 mm or more and 60 mm or less, and more preferably 25 mm or more and 50 mm or less. The diameter of the flow path at the downstream end of tapered section 3 (i.e., the minimum diameter of the flow path) is preferably 10 mm or more and 40 mm or less, and more preferably 15 mm or more and 35 mm or less, from the viewpoint of improving the spray molding accuracy.

[0030] The ratio of the diameter of the flow path at the downstream end of the tapered section 3 to the diameter of the flow path at the upstream end of the tapered section 3 (downstream flow path diameter / upstream flow path diameter) is preferably 0.90 or less, more preferably 0.85 or less, from the viewpoint of suppressing separation of the powder material and the liquid material. Moreover, from the viewpoint of allowing the spraying material to pass smoothly, the ratio is preferably 0.40 or more, more preferably 0.50 or more.

[0031] The length of the tapered section 3 is preferably 30 mm or more and 160 mm or less, more preferably 30 mm or more and 120 mm or less, from the viewpoint of suppressing acceleration of the spray speed of the spray material. The length of the tapered section 3 refers to the distance from the upstream end to the downstream end of the tapered section 3.

[0032] The extension section 4 is attached to the downstream end of the tapered section 3. The cross-sectional shape of the flow path of the extension section 4 is circular, similar to the cross-sectional shapes of the flow paths of the bent section 2 and the tapered section 3. From the viewpoint of the straightness of the spraying material, it is preferable that the diameter of the flow path is equal to the diameter of the downstream end of the tapered section 3.

[0033] From the viewpoint of adjusting the spraying speed of the spraying material to an appropriate speed, the length of the extension 4 is preferably from 10 mm to 100 mm, more preferably from 15 mm to 75 mm. The length of the extension 4 refers to the distance from the upstream end to the downstream end of the extension 4.

[0034] The length of the flow path downstream of the bend 2 in the nozzle 1 (i.e., the length of the tapered section 3 and the extension section 4) is preferably 40 mm or more and 260 mm or less, and more preferably 45 mm or more and 195 mm or less. Downstream of the bend 2 in the nozzle 1, the speed of the spraying material, which has been decelerated at the bend 2 of the nozzle 1, is accelerated by the compressed air. Therefore, by setting the length of the flow path downstream of the bend 2 in the nozzle 1 within the above range, the spraying speed of the spraying material sprayed from the nozzle 1 can be made appropriate.

[0035] The nozzle 1 according to this embodiment can be suitably used in the dry spraying method.

[0036] The nozzle 1 of this embodiment has a bent section 2 where the flow path is curved, and the rebound elasticity modulus on the flow path side of the bent section 2 is 0.8 or less, so that the spraying material can be collided with the bent section 2 to slow down its speed, thereby efficiently reducing the spraying speed of the spraying material.

[0037] In the nozzle 1 according to this embodiment, the angle of the flow path at the bend 2 is 15 degrees or more and 90 degrees or less, so that the speed of the spray material at the bend 2 can be reduced more reliably.

[0038] In the nozzle 1 of this embodiment, the flow path at the bend 2 is curved in an arc shape, and the radius of the arc of the curved flow path at the bend 2 is 30 mm or more and 160 mm or less, thereby more reliably reducing the speed of the spray material at the bend 2.

[0039] The nozzle 1 of this embodiment has a tapered section 3 downstream of the bend section 2, in which the diameter of the flow path gradually decreases as the flow path moves downstream, thereby suppressing separation of the powder material and liquid material that make up the spray material within the nozzle 1 and suppressing dripping from the tip of the nozzle 1.

[0040] <Spraying method> The spraying method according to this embodiment is a method of spraying a spray material, which is a mixture of a powder material containing cement and a liquid material containing water, onto an object using a nozzle 1 of a sprayer that sprays the spray material through a flow path, the nozzle 1 having a bent portion 2 where the flow path is curved, the flow path side of the bent portion 2 having a rebound resilience modulus of 0.8 or less, and the method includes a step of spraying the spray material from the nozzle 1 onto the object. The nozzle 1 used in the spraying method according to this embodiment is the same as the nozzle 1 described above.

[0041] In the step of spraying the spray material, the spray material is sprayed onto the target object by ejecting it from the nozzle 1. The sprayer to which the nozzle 1 is attached is not particularly limited, and any conventionally known sprayer can be used.

[0042] In the process of spraying the spraying material, in order to spray the spraying material densely and to avoid deforming the sprayed material, it is preferable to adjust the velocity of the spraying material particles 0.1 m from the outlet 12 of the nozzle 1 (i.e., the downstream end of the extension portion 4) to be 5.0 m / s or more and 25 m / s or less, and it is more preferable to adjust it to be 6.5 m / s or more and 20 m / s or less.

[0043] In the step of spraying the spray material, from the viewpoint of adjusting the speed of the particles of the spray material to an appropriate speed, the air speed at the inlet 11 of the nozzle 1 (i.e., the upstream end of the bend 2) is preferably 50 m / s or more and 150 m / s or less, and more preferably 60 m / s or more and 120 m / s or less. Also, from the viewpoint of adjusting the speed of the particles of the spray material to an appropriate speed, the pressure is preferably 0.08 MPa or more and 0.24 MPa or less, and more preferably 0.10 MPa or more and 0.20 MPa or less.

[0044] In the step of spraying the spraying material, the mass ratio of the air flow rate to the spraying material flow rate may be, for example, 4 mass % or more and 16 mass % or less, or 5 mass % or more and 12 mass % or less.

[0045] The spraying material is a mixture of a powder material containing cement and a liquid material containing water. The mass ratio of the liquid material to the powder material may be, for example, 0.08% by mass or more and 0.35% by mass or less, or 0.10% by mass or more and 0.30% by mass or less.

[0046] The cement contained in the powder material is not particularly limited, and examples thereof include Portland cements such as ordinary Portland cement, high-early-strength Portland cement, ultra-high-early-strength Portland cement, moderate-heat Portland cement, sulfate-resistant Portland cement, and white Portland cement as specified in JIS R 5210:2019; mixed cements such as blast-furnace cement, fly ash cement, and silica cement; ultra-rapid-hardening cement, alumina cement, and other known cements. Note that one type of cement may be used alone, or two or more types may be used in combination.

[0047] The powder material may also contain aggregate. Fine aggregate and / or coarse aggregate can be used as the aggregate. When coarse and fine aggregates are used as aggregates, the sprayed material constitutes concrete. When only fine aggregate is used as aggregate, the sprayed material constitutes mortar. Note that fine aggregate refers to aggregate that passes entirely through a 10 mm mesh sieve and 85% or more by mass passes through a 5 mm mesh sieve. Coarse aggregate refers to aggregate that remains on a 5 mm mesh sieve at least 85% by mass (JIS A 0203:2019).

[0048] Examples of fine aggregate include naturally occurring sand such as river sand, land sand, mountain sand, sea sand, crushed sand, and crushed limestone sand, as specified in JIS A 5308:2019 Appendix A Aggregates for Ready-Mixed Concrete, and blast furnace slag. One type of fine aggregate may be used alone, or two or more types may be used in combination. The content of the fine aggregate is not particularly limited, and may be, for example, 50% by mass or more and 300% by mass or less, or 80% by mass or more and 250% by mass or less, relative to the cement.

[0049] Examples of coarse aggregate include natural aggregates such as river gravel, mountain gravel, and sea gravel, as defined in JIS A 5308:2019 Appendix A Aggregates for Ready-Mixed Concrete; artificial aggregates such as crushed stone such as sandstone, hard limestone, basalt, and andesite; and recycled aggregate. One type of coarse aggregate may be used alone, or two or more types may be used in combination. The content of the coarse aggregate is not particularly limited, and may be, for example, 180% by mass or more and 210% by mass or less, or 190% by mass or more and 200% by mass or less, relative to the cement.

[0050] The powder material may also contain an admixture. Examples of admixtures include inorganic fine powders such as fly ash, silica fume, cement kiln dust, blast furnace fume, ground granulated blast furnace slag, ground granulated blast furnace slag, ground granulated converter slag, gypsum hemihydrate, expanding agents, limestone fine powder, quicklime fine powder, and dolomite fine powder, as well as inorganic fillers such as sodium bentonite, calcium bentonite, attapulgite, sepiolite, activated clay, acid clay, allophane, imogolite, shirasu (volcanic ash), shirasu balloons, kaolinite, metakaolin (calcined clay), synthetic zeolite, artificial zeolite, mordenite, and clinoptilolite. One type of admixture may be used alone, or two or more types may be used in combination.

[0051] The powder material may also contain an admixture. Examples of admixtures include air-entraining agents, air-entraining water-reducing agents, high-performance water-reducing agents, superplasticizers, separation-reducing agents, setting retarders (e.g., tartaric acid), setting accelerators (e.g., aluminum sulfate), quick-setting agents, shrinkage-reducing agents, foaming agents, and waterproofing agents. One type of admixture may be used alone, or two or more types may be used in combination.

[0052] The powder material may also contain a fibrous material. Examples of the fibrous material include glass fiber, steel fiber, vinylon fiber, aramid fiber, polypropylene fiber, and carbon fiber. One type of fibrous material may be used alone, or two or more types may be used in combination.

[0053] The water contained in the liquid material is not particularly limited, and examples thereof include tap water, industrial water, recycled water, groundwater, river water, and rainwater. It is preferable that the water does not contain organic matter, chloride ions, sodium ions, potassium ions, etc., which have adverse effects on the hydration reaction of the concrete composition and the pavement concrete, or if it does contain such ions, it is in extremely small amounts. It is more preferable that the water be tap water or industrial water of stable quality. The liquid material may also contain materials other than water. Examples of materials other than water include the above-mentioned admixtures.

[0054] In the spraying method according to this embodiment, the nozzle 1 has a curved section 2 where the flow path is curved, and the flow path side of the curved section 2 has a resilience modulus of 0.8 or less, so that the spraying speed of the spraying material can be efficiently reduced by slowing down the speed of the spraying material by colliding it with the curved section 2. As a result, the spraying material can be prevented from being blown away.

[0055] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made within the scope that does not deviate from the gist of the present invention.

[0056] For example, the nozzle 1 according to the above embodiment has been described as having a curved portion 2, a tapered portion 3, and an extension portion 4. However, the present invention is not limited to this configuration, and the nozzle 1 may, for example, not have the tapered portion 3 and the extension portion 4, or may have the curved portion 2 and the tapered portion 3 or the extension portion 4.

[0057] Furthermore, in the nozzle 1 according to the above embodiment, the bending portion 2, tapered portion 3, and extension portion 4, which are formed as separate bodies, are connected together for use. However, the present invention is not limited to this configuration, and the nozzle 1 (i.e., the bending portion 2, tapered portion 3, and extension portion 4) may be formed integrally.

[0058] Furthermore, in the nozzle 1 according to the above embodiment, the shape of the flow path of the curved portion 2, tapered portion 3, and extended portion 4 has been described as being circular. However, the present invention is not limited to this configuration, and the shape of the flow path may be, for example, elliptical or polygonal. Note that when the shape of the flow path is elliptical, the minor axis is taken as the diameter of the flow path, and when the shape of the flow path is polygonal, the diameter of the flow path is taken as the diameter of the inscribed circle.

[0059] The present invention includes the following aspects. [1] A nozzle of a sprayer that sprays a spray material that is a mixture of a powder material containing cement and a liquid material containing water through a flow path, The flow path has a curved bend, The nozzle has a modulus of resilience of 0.8 or less on the flow path side of the bent portion. [2] The nozzle according to [1] above, wherein the angle of the flow path at the bend is 15 degrees or more and 90 degrees or less. [3] The nozzle described in [1] or [2] above, wherein the flow path at the bend is curved in an arc shape, and the radius of the arc of the curved flow path at the bend is 30 mm or more and 160 mm or less. [4] The nozzle according to any one of [1] to [3] above, which has a tapered portion downstream of the bent portion, in which the diameter of the flow path gradually decreases toward the downstream side of the flow path. [5] A spraying method in which a spraying material, which is a mixture of a powder material containing cement and a liquid material containing water, is sprayed onto an object using a nozzle of a sprayer that sprays the spraying material through a flow path, The nozzle The flow path has a curved bend, The rebound resilience of the bent portion on the flow path side is 0.8 or less, A spraying method comprising a step of spraying the spray material from the nozzle onto an object. [Example]

[0060] Examples of the present invention will be described below, but the present invention is not limited to the following examples.

[0061] A simulation analysis was performed using Ansys Fluent 2022 R1 (manufactured by ANSYS, Inc.) to confirm whether it is possible to reduce the spray speed of the spray material in the above-mentioned nozzle 1. The simulation analysis was performed under the following conditions.

[0062] (Analysis shape) Open space up to 500mm from the nozzle tip (Physical properties of air) ANSYS FLUENT database (Turbulence model) k-ε model The spray velocity of the spray material was assumed to be equal to the spray velocity of the particles sprayed from the nozzle tip.

[0063] As shown in Figure 1, the geometric model of nozzle 1 created for use in the simulation comprises a bent section 2, a tapered section 3, and an extended section 4. Details of the bent section 2, the tapered section 3, and the extended section 4 are shown in Table 1. Table 1 also shows details of the spraying conditions for the spraying material.

[0064] [Table 1]

[0065] As can be seen from the results in Table 1, the nozzles 1 of each example that satisfy all of the constituent requirements of the present invention show a relatively low numerical value indicating the particle velocity at a position 0.1 m away from the nozzle outlet 12 relative to the particle velocity at the inlet 11 of the nozzle 1, and therefore it is recognized that the spray velocity of the spraying material can be reduced. In other words, nozzles that satisfy all of the constituent requirements of the present invention can efficiently reduce the spray velocity of the spraying material. [Explanation of symbols]

[0066] 1 nozzle 11 Nozzle inlet 12 Nozzle outlet 2 Bending section 3 Tapered section 4 Extension 5 Nozzle Liner

Claims

1. A nozzle of a sprayer that sprays a spray material, which is a mixture of a powder material containing cement and a liquid material containing water, through a flow path, The flow path has a curved bend, The nozzle has a resilience modulus of 0.8 or less on the flow path side of the bent portion.

2. The nozzle according to claim 1 , wherein an angle of the flow passage at the bend is equal to or greater than 15 degrees and equal to or less than 90 degrees.

3. 3. The nozzle according to claim 1, wherein the flow passage at the bent portion is curved in an arc shape, and a radius of the arc of the curved flow passage at the bent portion is 30 mm or more and 160 mm or less.

4. 3. The nozzle according to claim 1, further comprising a tapered portion downstream of the bent portion, the diameter of the flow passage gradually decreasing toward the downstream of the flow passage.

5. A spraying method for spraying a spray material, which is a mixture of a powder material containing cement and a liquid material containing water, onto an object using a nozzle of a sprayer that sprays the spray material through a flow path, the nozzle comprising: The nozzle is The flow path has a curved bend, The resilience modulus of the bent portion on the flow path side is 0.8 or less, A spraying method comprising a step of spraying a spray material from the nozzle onto an object.

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