JP2008238008A - Nozzle for wet spraying coating - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nozzle for wet spraying coating which enables improving the filling property of a wet spraying material, e.g. mortar, even in the presence of substances interrupting spraying to a garget material, while keeping high the spraying pressure of the spraying material. <P>SOLUTION: The nozzle for wet spraying coating has a cylindrical base portion 1 having two or more air holes which are formed in the outer periphery and supply pressurized air to a wet spraying material force-fed to the central part and a nozzle tip portion extending from the base portion to the discharge outlet. In the discharge outlet of the tip portion of the nozzle, there is provided a negative pressure generating mechanism 4 which generates a negative pressure inside the wet spraying material so as to prevent the wet spraying material to be discharged from the discharge outlet from spreading in the circumferential direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a nozzle for wet spraying construction, and more particularly to a nozzle for wet spraying construction for spraying a wet spraying material using pressurized air.

  In repairing / reinforcing concrete structures, wet spraying materials such as mortar are sprayed onto repaired parts. For these operations, a nozzle having the shape shown in FIG. 1 is generally used. In this nozzle, the mortar kneaded to the cylindrical base 1 is pumped to the center of the base by a pump (not shown), and wet spray material is discharged from the nozzle tip using pressurized air such as compressed air. It sprays on concrete structures.

  The compressed air is guided to the outer peripheral portion of the base portion 1 by the compressed air introduction pipe 2 and further introduced into the base portion 1 through the air holes 3 formed in the outer peripheral portion. The compressed air ejected from the air holes 3 pushes the mortar into the nozzle tip in the direction of the nozzle tip, and discharges the mortar from the discharge port at the nozzle tip.

Such spraying nozzles often use a mortar material and a curing agent together, and in order to obtain a mixing property between the spraying material and a curing liquid and a high construction pressure, the nozzle tip portion is shown in FIG. As described above, the nozzle has a tapered shape (see Patent Document 1), and the nozzle has improved mixing properties by devising the number of installed air holes and the opening area formed on the outer periphery of the base (see Patent Document 2). ) Etc. have been proposed.
Japanese Patent No. 3737626 JP 2001-208482 A

  In this way, with conventional nozzles, in order to obtain high working pressure, high density mortar, and high uniformity mortar, pressure fluctuation in the nozzle is suppressed, and good mixing and dispersibility of mortar inside the nozzle Was demanded.

  On the other hand, in repairing / reinforcing work for concrete structures, etc., when repairing a deteriorated part, concrete is often suspended until the reinforcing bar is completely exposed. And, when mortar material is sprayed on such repaired parts, the mortar adheres to the exposed reinforcing bars and the mortar on the back side of the reinforcing bars is insufficient, and there is a problem with the filling ability of the mortar on the repaired parts, particularly on the back side of the reinforcing bars. Will occur.

  In order to solve this problem, conventionally, at the time of spraying, the amount of compressed air is reduced, and the nozzle is moved closer to the spraying object for construction. However, in this construction method, the mortar spraying pressure on the back side of the reinforcing bar was low, and as a result, sufficient adhesion strength of the mortar could not be obtained.

  The problem to be solved by the present invention is to solve the above-described problem, when there is an object that blocks the spraying object while maintaining a high spraying pressure of a wet spraying material such as mortar. However, it is providing the nozzle for wet spraying construction which can make the filling property of a spraying material high.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a cylindrical base portion in which a plurality of air holes for supplying pressurized air to the wet spray material fed to the center portion are formed on the outer periphery, In a nozzle for wet spraying construction having a nozzle tip extending from the base to the discharge port, the wet spray material discharged from the discharge port is prevented from spreading in the circumferential direction at the discharge port of the nozzle tip. Therefore, it has a negative pressure generating means for generating a negative pressure inside the wet spray material.

  According to a second aspect of the present invention, in the wet spraying nozzle according to the first aspect, the negative pressure generating means is a hardware disposed in a portion including the center of the discharge port.

  According to a third aspect of the present invention, in the wet spraying construction nozzle according to the second aspect, the hardware has an extending portion extending in an inner direction of the nozzle tip.

  The invention according to claim 4 is the nozzle for wet spraying construction according to any one of claims 1 to 3, wherein the length from the air hole to the discharge port is 40 to 200 mm.

  The invention according to claim 5 is the wet spray nozzle according to any one of claims 1 to 4, wherein the angle formed by the central axis in the air hole and the central axis of the cylindrical base is 20 It is ˜30 °.

  The invention according to claim 6 is the nozzle for wet spraying construction according to any one of claims 1 to 5, wherein the wet spraying material is mortar.

  According to the first aspect of the present invention, a plurality of air holes for supplying pressurized air to the wet spray material fed to the center are formed on the outer periphery, and the base extends from the base to the discharge port. In a wet spraying nozzle having a nozzle tip, the discharge port at the nozzle tip has a negative pressure generating means for generating a negative pressure inside the wet spray material. It is possible to suppress the wet spray material discharged from spreading in the circumferential direction, and to improve the straightness of the spray material discharged from the nozzle. For this reason, even if there is something that obstructs the spraying of objects such as reinforcing bars, the problem that the spraying material does not adhere over a wide area on the back of the reinforcing bar can be solved, and the spraying pressure of the wet spraying material Can also be kept high.

  According to the second aspect of the present invention, since the negative pressure generating means is a hardware disposed in a portion including the center of the discharge port, the mechanical strength of the negative pressure generating means can be set high, and a wet spray material such as mortar There is no mechanical deformation of the negative pressure generating means even when jetting is injected at a high pressure. Moreover, when the material which comprises a nozzle front-end | tip part is a metal, it becomes possible to attach a negative pressure generation means easily by welding, mechanical engagement, etc.

  According to the invention of claim 3, since the hardware has an extended portion extending in the inner direction of the nozzle tip, the spray material does not interfere with the flow of the spray material and is discharged from the discharge port. It becomes possible to generate a negative pressure effectively inside.

  According to the invention according to claim 4, since the length from the air hole to the discharge port is 40 to 200 mm, it is possible to improve the straightness of the discharged spray material without disturbing the flow of the spray material, It becomes possible to make spraying pressure and the filling property of a spraying material higher.

  According to the invention of claim 5, since the angle formed by the central axis in the air hole and the central axis of the cylindrical base is 20 to 30 °, the spray material is placed in a direction along the central axis direction of the base. It becomes possible to extrude, and it is possible to suppress the spray material from spreading in the circumferential direction even when discharged from the discharge port.

  According to the invention according to claim 6, since the wet spray material is mortar, the wet spraying nozzle of the present invention can be suitably used for spraying mortar during repair work of concrete structures. It becomes.

The nozzle for wet spraying construction of the present invention will be described in detail below.
FIG. 2 is a schematic cross-sectional view of the nozzle for wet spraying according to the present invention, and the left side of the drawing is a front view of the discharge port of the nozzle.
The nozzle for wet spraying construction of the present invention has a cylindrical shape in which a plurality of air holes 3 for supplying compressed air as pressurized air are formed on the outer periphery to a wet spraying material such as mortar fed to the center. In the wet spraying nozzle having a base 1 and a nozzle tip extending from the base 1 to the discharge port, a negative pressure is generated at the discharge port of the nozzle tip to generate a negative pressure inside the wet spray material. It has a pressure generating means 4.

  As a result of diligent research, the present inventors have found that when there is a shield such as a reinforcing bar in front of the object to be sprayed in a repaired part of a concrete structure, the filling property of a spraying material such as mortar is reduced. The cause was found to be that the mortar ejected from the nozzle spread in the direction perpendicular to the ejection direction (circumferential direction of the spray material ejected from the nozzle), which led to the present invention. Is.

  Therefore, as in the present invention, by providing the negative pressure generating means at the discharge port, the wet spray material discharged from the discharge port is prevented from spreading in the circumferential direction, and the spray material discharged from the nozzle goes straight. It becomes possible to improve the nature. For this reason, even if there is something that obstructs the spraying of objects such as reinforcing bars, the problem that the spraying material does not adhere over a wide area on the back of the reinforcing bar can be solved, and the spraying pressure of the wet spraying material Can also be kept high.

  Although the material which comprises a nozzle is not specifically limited, A lightweight thing with little possibility of causing reaction with mortar, such as aluminum, a hard plastic, rubber | gum, is preferable. The negative pressure generating means 4 can be made of the same material as the nozzle body. However, when spraying mortar or the like, it is desirable to form the negative pressure generating means 4 with a metal having high mechanical strength. Furthermore, when the material constituting the nozzle tip is a metal, the negative pressure generating means can be easily attached by welding or the like.

  The shape of the negative pressure generating means 4 is preferably a circular cross section as shown in FIG. 2 and positioned at the center of the nozzle outlet, but is not limited to this. For example, the cross sectional shape is a polygonal shape. It is possible to adjust the relative position of the negative pressure generating means with respect to the nozzle body, or to adjust the relative position of the negative pressure generating means with respect to the nozzle body. It is also possible to configure to optimize the position.

  Further, the negative pressure generating means 4 can be provided with an extending portion extending in the inner direction of the nozzle tip as shown in the schematic cross-sectional view of FIG. When there is no such stretched portion, the flow of the spray material changes suddenly by the negative pressure generating means, and the straightness of the spray material discharged from the discharge port is hindered. Furthermore, the shape of the stretched portion is tapered toward the inside of the nozzle, so that the flow of the spraying material is not hindered, and when the spraying material is discharged from the discharge port, the straightness of the spraying material While maintaining the above, it becomes possible to effectively generate a negative pressure inside the spray material.

  The negative pressure generating means is mounted in the nozzle tip by providing a support member (not shown) extending radially from the negative pressure generator 4 and welding or mechanically supporting the support member to the inner surface of the nozzle tip or the nozzle outlet. It is possible to fix by engaging with each other.

In order to improve the straightness of the spray material discharged from the nozzle, it is preferable to set the length from the air hole to the discharge port in the range of 40 to 200 mm as the shape of the nozzle. In particular, when mortar is used as the wet spray material, a range of 40 to 200 mm is preferable.
When the length of the tip of the nozzle is 40 mm or less, proper straightness cannot be obtained. When the length is 200 mm or more, the pressure of the spray material passing through the nozzle increases, and the compressed air In addition to the increase in pressure, the flow of the spray material is disturbed as the pressure of the compressed air increases. Further, when the spray material is mortar, if it is 200 mm or more, the possibility of increasing occurrence of mortar clogging in the nozzle increases. Also, nozzles that are too long in terms of operability are not used.
The inner diameter of the wet spray nozzle is preferably in the range of 10 to 20 mm in consideration of the discharge speed of the spray material.

  The angle formed by the central axis in the air hole of the nozzle and the central axis of the cylindrical base is preferably in the range of 20 to 30 °. Making the angle smaller than 20 ° is not only difficult due to the thickness of the outer peripheral portion constituting the nozzle base, but if the angle is too small, the pressure on the entire spraying material in the nozzle is reduced. The pressure will drop. On the other hand, when the angle is larger than 30 °, the pressing force increases in the direction perpendicular to the central axis direction of the nozzle base, which disturbs the flow of the spray material, and impedes the straightness of the spray material discharged from the discharge port. The Rukoto.

  As described above, the wet spraying construction nozzle of the present invention can be suitably used when the wet spraying material is mortar, and in particular, when a reinforcing bar is exposed in a concrete structure repair work. It is possible to further improve the filling properties and adhesion strength of the mortar.

  A nozzle having the shape shown in FIG. 3 was prepared and tested. However, as shown in Table 1, the presence or absence of the negative pressure generating means 4 or the presence or absence of the negative pressure generating means extending into the nozzle, the angle of the air hole, and the length of the nozzle tip were variously adjusted.

As shown in FIG. 4, the nozzle 10 is placed 1 m away from the wall surface 20 as shown in FIG. 4, the mortar discharge rate is adjusted to 6 kg / min, the air amount is adjusted to 200 m ³ / h, and the mortar is adjusted to the wall surface 20 for 20 seconds. The spray was carried out. And the shape of the mortar 21 sprayed on the wall surface was measured. The measurement results are shown in the graph of FIG.
Further, from the graph of FIG. 5, the half value of the maximum height (referred to as “half value”), the mortar width at half value, and the spread angle from the nozzle at half value were measured, and the results are shown in Table 1.

  From the graph of FIG. 5 or the result of Table 1, when [a, b, c] and [d, e, f] are compared, in the case where there is a negative pressure generating means, the straightness of the spray material is high, and [a ] And [c], the straightness is higher when there is stretching inside the nozzle.

Further, comparing [a] and [b], the smaller the air introduction angle, the higher the straightness of the spray material.
Further, comparing [e] and [f], it is understood that the longer the tip of the nozzle, the higher the straightness of the spray material.

  According to the present invention, while maintaining the spray pressure of a wet spray material such as mortar at a high level, the filling property of the spray material can be increased even when there is an object that blocks the spray onto the spray target. It becomes possible to provide a nozzle for wet spraying construction that is possible.

It is the schematic of the conventional nozzle for spray construction. It is the schematic of the nozzle for wet spray construction of this invention. It is the schematic of the nozzle used for the test. It is a figure explaining a test method. It is a graph which shows the shape of the mortar sprayed on the wall surface.

Explanation of symbols

1 Nozzle body (base)
2 Compressed air introduction pipe 3 Air hole 4 Negative pressure generating means 10 Nozzle 20 Wall surface 21 Mortar

Claims (6)

A wet-type spray having a cylindrical base portion having a plurality of air holes formed on the outer periphery for supplying pressurized air to the wet-sprayed material pumped to the center, and a nozzle tip extending from the base portion to the discharge port. In mounting nozzles,
The discharge port at the tip of the nozzle has negative pressure generating means for generating a negative pressure inside the wet spray material in order to prevent the wet spray material discharged from the discharge port from spreading in the circumferential direction. A nozzle for wet spraying, characterized by   2. The nozzle for wet spraying construction according to claim 1, wherein the negative pressure generating means is a metal piece arranged at a portion including the center of the discharge port.   3. The nozzle for wet spraying construction according to claim 2, wherein the hardware has an extending portion extending in the inner direction of the nozzle tip.   The nozzle for wet spraying construction according to any one of claims 1 to 3, wherein the length from the air hole to the discharge port is 40 to 200 mm.   The wet spraying nozzle according to any one of claims 1 to 4, wherein an angle formed by the central axis in the air hole and the central axis of the cylindrical base is 20 to 30 °. Wet spraying nozzle.   The wet spraying construction nozzle according to any one of claims 1 to 5, wherein the wet spraying material is mortar.

Images