JP7661998B2 - Blasting device for inner surface of pipe and blasting method for inner surface of pipe - Google Patents

Description

The present invention relates to a blasting device for the inner surface of a pipe and a blasting method for the inner surface of a pipe.

Conventionally, when coating the inner surface of a steel pipe, a blasting process is often carried out in which an abrasive material is collided with the inner surface in order to remove dirt from the inner surface and adjust the surface roughness of the inner surface. The mainstream blasting device for abrasively cleaning the inner surface of a steel pipe uses a method in which compressed air and an abrasive material are mixed and then sprayed against the inner wall of the pipe (compressed air spraying method). For example, the technology disclosed in Patent Document 1 is an application technology for a blasting device that uses this compressed air spraying method. The compressed air spraying method generally involves moving a blasting device inside the steel pipe in the longitudinal direction of the pipe while rotating the steel pipe, spraying an abrasive material against the inner surface of the pipe to abrasively clean it.

JP 2017-052029 A

In the blasting device described in Patent Document 1, in order to uniformly abrasively clean the inner surface of the pipe, the rotation speed of the steel pipe needs to be significantly faster than the speed at which the blasting device advances inside the pipe, resulting in restrictions on productivity and operating conditions. To alleviate these restrictions, for example, a blasting device that uses centrifugal force to release abrasive cleaning material from a blasting head rotated around a rotation axis and collide it with the inner wall of the pipe to abrasively clean the inner surface of the pipe is conceivable. However, in a blasting device that rotates a blasting head to collide abrasive cleaning material with the inner surface of the pipe, if the angle of incidence at which the abrasive cleaning material released from the blasting head collides with the inner surface of the pipe is small, the abrasive cleaning efficiency is reduced.

The present invention was made in consideration of the above problems, and its purpose is to provide a blasting device for the inner surface of a pipe and a blasting method for the inner surface of a pipe that can improve the efficiency of cleaning.

In order to solve the above problems and achieve the objectives, the blasting device for the inner surface of a pipe according to the present invention is characterized by comprising a blasting head that releases abrasives by rotating around a rotation axis, and a guide member that reflects the abrasives released from the blasting head with a guide surface and guides it to the inner surface of the pipe, which is the inner peripheral surface of the pipe material.

The blasting device for the inner surface of a pipe according to the present invention is characterized in that, in a plan view, the direction perpendicular to both the rotation axis and the pipe longitudinal direction, which is the longitudinal direction of the pipe material, is defined as the X-axis, the pipe longitudinal direction is defined as the Y-axis, and the angle between the X-axis and a straight line connecting the rotation axis and the release position when the abrasive material is released from the blast head is defined as θ. In this case, at least a portion of the shape of the guide surface satisfies the relational expression dy/dx = -tan(π/4 - θ/2) in the XY plane.

The blasting device for the inner surface of a pipe according to the present invention is characterized in that it is equipped with a plurality of the above-mentioned guide members.

The blasting device for the inner surface of a pipe according to the present invention is characterized in that, in the above invention, one or more of the multiple guide members are removable.

The blasting device for the inner surface of a pipe according to the present invention is characterized in that the blast head and the guide member are supported by the same support member.

The blasting device for the inner surface of a pipe according to the present invention is characterized in that, in the above invention, the blast head is supported by a first support member, and the guide member is supported by a second support member separate from the first support member.

The blasting device for the inner surface of a pipe according to the present invention is characterized in that, in the above invention, the guide member is disposed in at least a part of the area where, in a plan view, the angle between the direction of incidence of the abrasive material discharged from the blast head and the inner surface of the pipe is 45 degrees or less when the abrasive material collides with the inner surface of the pipe.

The method for blasting the inner surface of a pipe according to the present invention is characterized in that the abrasive material discharged from the blast head is reflected by the guide surface of the guide member by rotating the blast head around the rotation axis, and is collided with the inner surface of the pipe, which is the inner peripheral surface of the pipe material.

The method for blasting the inner surface of a pipe according to the present invention is characterized in that, in a plan view, the direction perpendicular to both the rotation axis and the pipe longitudinal direction, which is the longitudinal direction of the pipe material, is defined as the X-axis, the pipe longitudinal direction is defined as the Y-axis, and the angle between the X-axis and a straight line connecting the rotation axis and the release position when the abrasive is released from the blast head is defined as θ. In this case, at least a portion of the shape of the guide surface satisfies the relational expression dy/dx = -tan(π/4 - θ/2) in the XY plane.

The method for blasting the inner surface of a pipe according to the present invention is characterized in that it uses a plurality of the above-mentioned guide members.

The method for blasting the inner surface of a pipe according to the present invention is characterized in that, in the above invention, one or more of the multiple guide members are removable.

The method for blasting the inner surface of a pipe according to the present invention is characterized in that, in the above invention, the blast head and the guide member supported by the same support member are inserted into the pipe material from one end side in the pipe longitudinal direction, which is the longitudinal direction of the pipe material.

The method for blasting the inner surface of a pipe according to the present invention is characterized in that, in the above invention, the blast head is supported by a first support member, the guide member is supported by a second support member different from the first support member, and the blast head is inserted into the pipe material from one end side in the pipe longitudinal direction, which is the longitudinal direction of the pipe material, and the guide member is inserted into the pipe material from the other end side in the pipe longitudinal direction.

The method for blasting the inner surface of a pipe according to the present invention is characterized in that, in the above invention, the guide member is disposed in at least a part of the area where, in a plan view, the angle between the direction of incidence of the abrasive material discharged from the blast head and the inner surface of the pipe is 45 degrees or less when the abrasive material collides with the inner surface of the pipe.

The blasting device and blasting method for the inner surface of a pipe according to the present invention have the effect of improving the efficiency of cleaning.

FIG. 1 is a side view showing a schematic configuration of a blasting device according to a first embodiment. FIG. 2 is a top view showing a schematic configuration of the blasting device according to the first embodiment. FIG. 3 is a diagram showing the ejection direction of the abrasive material discharged from the blast head when no guide is provided. FIG. 4 is an explanatory diagram of an example of the shape of a guide surface in the blasting device according to the first embodiment. FIG. 5 is a diagram showing another example of how the guide member is provided in the blasting machine according to the first embodiment. FIG. 6 is a top view showing a schematic configuration of a blasting device according to the second embodiment. FIG. 7 is an explanatory diagram showing an example of the arrangement of two guide members in the blasting machine according to the second embodiment. FIG. 8 is a top view showing a schematic configuration of a blasting device according to the third embodiment. FIG. 9 is a top view showing a schematic configuration of a blasting device according to the fourth embodiment. FIG. 10 is a top view showing a schematic configuration of a blasting device according to the fifth embodiment.

(Embodiment 1)
A blasting device and a blasting method according to a first embodiment of the present invention will be described below. Note that the present invention is not limited to this embodiment.

Figure 1 is a side view showing the schematic configuration of a blasting device according to embodiment 1. Figure 2 is a top view showing the schematic configuration of a blasting device according to embodiment 1.

The blasting device 1 according to the first embodiment includes a cart 11, a blasting head 12, an upper boom 13, a lower boom 14, a belt conveyor 15, and a guide member 16. The cart 11 has a plurality of wheels 111 and is configured to be able to run on the floor 2. The upper boom 13 and the lower boom 14 are long plate-like members, and the base end side in the longitudinal direction is supported by a cantilever on the side of the cart 11. The upper boom 13 and the lower boom 14 are arranged opposite to each other at a predetermined interval in the height direction of the cart 11, and the blasting head 12 is rotatably supported at the tip side in the longitudinal direction of each of them via a rotating shaft 121. In this embodiment, the upper boom 13 and the lower boom 14 constitute a first support member that supports the blasting head 12. The blasting head 12 is driven to rotate by a driving source such as a motor (not shown) provided in the blasting device 1, and can rotate in a counterclockwise direction (the direction of the arrow C in FIG. 2) when viewed from above, as shown in FIG. 2.

The belt conveyor 15 includes a conveyor belt 151 and a plurality of conveyor rolls 152 that rotatably stretch the conveyor belt 151. The belt conveyor 15 is disposed above the upper boom 13 and is supported by at least one of the dolly 11 and the upper boom 13 by a support member (not shown). The conveyor belt 151 is long in the same direction as the longitudinal direction of the upper boom 13, and conveys a plurality of abrasive cleaning materials 17 on its upper outer peripheral surface to the tip side (arrow B direction in the figure) in the longitudinal direction of the conveyor belt 151. At least one of the plurality of conveyor rolls 152 is a drive roll that is driven to rotate by a drive source such as a motor (not shown), and the remaining conveyor rolls are driven rolls that rotate with the rotation of the conveyor belt 151 that rotates in conjunction with the rotation of the drive roll. The longitudinal tip position of the conveyor belt 151 is located closer to the dolly 11 than the tip position of the upper boom 13. At the tip of the upper boom 13, an inlet 131 is provided that penetrates the upper boom 13 in the thickness direction and is used to feed the abrasive material 17 into the blast head 12. The abrasive material 17 transported to the longitudinal tip position by the conveyor belt 151 is fed from the conveyor belt 151 through the inlet 131 into the blast head 12. The abrasive material 17 fed into the blast head 12 is released by centrifugal force generated as the blast head 12 rotates.

The guide member 16 is a guide member that reflects some of the multiple abrasive cleaning materials 17 discharged from the blast head 12 at the guide surface 161 and guides them so that they fly toward the inner surface 31 of the steel pipe 3, which is the pipe material. The guide member 16 is supported by the upper boom 13 and the lower boom 14 with the support members 162 and 163.

In the blasting device 1 according to the first embodiment, the cart 11 is advanced in the longitudinal direction of the steel pipe 3, and the blast head 12 provided at the tip of the upper boom 13 and the lower boom 14 is advanced into the steel pipe 3 from one end in the longitudinal direction. Then, the cart 11 is advanced back and forth in the direction of the arrow A, which is the same direction as the longitudinal direction of the pipe, so that the blast head 12 advances back and forth in the longitudinal direction of the pipe within the steel pipe 3, and the multiple abrasive cleaning materials 17 discharged from the blast head 12 collide with the inner surface 31 of the pipe to blast (clean) it. In this embodiment, the steel pipe 3 is placed on multiple turning rolls 4, and when the blasting device 1 blasts the inner surface 31 of the pipe, the multiple turning rolls 4 rotate the steel pipe 3 in the direction of the arrow D in FIG. 1 around the axis of the steel pipe 3. This makes it possible to blast the entire inner surface 31 of the pipe uniformly by the blasting device 1 according to the first embodiment.

In addition, the blasting device 1 according to the first embodiment may be provided with a mechanism for recovering or reusing the used abrasive cleaning material 17 after it has been discharged from the blast head 12 and used to blast the inner pipe surface 31.

Figure 3 shows the spray direction of the abrasive material 17 discharged from the blast head 12 when the guide member 16 is not provided.

In the blasting device 1 according to the first embodiment, the abrasive material 17 is blown against the pipe inner surface 31 by the centrifugal force of the rotation of the blast head 12 to perform blasting. Here, the incident angle Φ of the abrasive material 17 with respect to the pipe inner surface 31 is the angle between the incident direction of the abrasive material and the pipe inner surface 31 when the abrasive material 17 discharged from the blast head 12 collides with the pipe inner surface 31 in a plan view as shown in FIG. 3. At this time, as shown in FIG. 3, the incident angle Φ of the abrasive material 17 sprayed in the longitudinal direction of the pipe with respect to the pipe inner surface 31 is small, so that the kinetic energy of the abrasive material 17 is not efficiently transmitted to the pipe inner surface 31, resulting in poor blasting efficiency. On the other hand, when the incident angle Φ with respect to the pipe inner surface 31 is large, for example, when the incident angle Φ is larger than 45 degrees, the kinetic energy of the abrasive material 17 is efficiently transmitted to the pipe inner surface 31, and the blasting efficiency is good, compared to when the incident angle Φ is small, for example, when the incident angle Φ is 45 degrees or less. In the blasting device 1 according to the first embodiment, the larger the incidence angle Φ, the better. For example, the incidence angle Φ is preferably 50 degrees or more, more preferably 70 degrees or more, and the maximum value of 90 degrees is optimal.

In the blasting device 1 according to the first embodiment, a part of the guide member 16 has a shape in which the collision angle of the abrasive material 17 with respect to the guide surface 161 is set so that the abrasive material 17 sprayed from the blast head 12 collides with the guide surface 161 of the guide member 16 and then collides perpendicularly with the inner pipe surface 31.

In the blasting device 1 according to the first embodiment, as shown in FIG. 2, the abrasive material 17 ejected from the blasting head 12 in the longitudinal direction of the pipe is reflected by the guide surface 161 of the guide member 16 in a plan view and flies toward the inner surface 31 of the pipe. This allows the abrasive material 17 ejected from the blasting head 12 in the longitudinal direction of the pipe to collide with the inner surface 31 of the pipe efficiently at an ejection angle that would result in poor abrasive cleaning efficiency if the guide surface 161 of the guide member 16 were not present. As a result, the overall abrasive cleaning efficiency of the inner surface 31 of the pipe can be improved. The shape of the guide surface 161 of the guide member 16 is designed so that the angle of incidence Φ of the abrasive material 17 that is reflected by the guide surface 161 and flies toward the inner surface 31 of the pipe is preferably 50 degrees or more, more preferably 70 degrees or more, and most preferably 90 degrees.

Figure 4 is an explanatory diagram of an example of the shape of the guide surface 161 in the blasting device 1 according to embodiment 1. As shown in Figure 4, in a plan view, an XY plane coordinate system is formed with the rotation axis 121 of the blasting head 12 as the origin, the direction perpendicular to both the rotation axis 121 of the blasting head 12 and the pipe longitudinal direction as the X axis, and the pipe longitudinal direction as the Y axis. In addition, in the XY plane, the injection angle, which is the angle between the X axis and the straight line L1 connecting the release position P1 and the rotation axis 121 when the abrasive cleaning material 17 is released from the blasting head 12, is θ. In the blasting device 1 according to embodiment 1, at least a part of the shape of the guide surface 161 in the guide member 16 is shaped to satisfy the relational expression dy/dx = -tan (π/4-θ/2) in the XY plane. That is, in the blasting device 1 according to the first embodiment, the shape of the guide member 16 is designed so that the inclination of the guide surface 161 (curved surface) at the position where the abrasive cleaning material 171 discharged from the discharge position P1 of the blast head 12 collides in the XY plane satisfies the above relational expression. When the abrasive cleaning material 17 collides with a portion of the guide surface 161 (curved surface) that satisfies the relational expression dy/dx = -tan (π/4-θ/2), the abrasive cleaning material 17 flies at a nearly right angle to the pipe inner surface 31 and collides with the pipe inner surface 31. As a result, the efficiency of the abrasive cleaning is improved.

In the present invention, the term "at least a part of the shape of guide surface 161 of guide member 16 satisfies the relational expression dy/dx = -tan(π/4-θ/2) in the XY plane" includes the following cases (1) to (3).
(1) The entire guide surface 161 is a curve that satisfies the above relational expression.
(2) A case where at least a part of the guide surface 161 is a curve that satisfies the above relational expression, but other parts do not satisfy the same.
(3) At least a portion of the guide surface 161 has a polygonal shape made up of a plurality of straight lines in a plan view, and at least a portion of an approximation curve of the polygonal shape satisfies the above relational expression.

Figure 5 shows another example of how the guide member 16 is provided in the blasting device 1 according to embodiment 1.

In the blasting device 1 according to the first embodiment, the guide member 16 may be supported by the boom 5, which is a second support member other than the upper boom 13 and the lower boom 14 that constitute the first support member supporting the blast head 12, as shown in FIG. 5. The boom 5 is a long plate-like member, and the base end side in the longitudinal direction is supported by a cantilever on the side of a cart (not shown) that can move forward and backward in the pipe longitudinal direction, for example. The guide member 16 is provided on the tip side in the longitudinal direction of the boom 5. The guide member 16 advances the boom 5 in the direction of the arrow E in FIG. 5, which is the same direction as the pipe longitudinal direction, from the side (the other end side in the pipe longitudinal direction) opposite to the side (one end side in the pipe longitudinal direction) where the blast head 12 enters the steel pipe 3 in the pipe longitudinal direction, to enter the steel pipe 3. Then, the guide member 16 may be arranged in the steel pipe 3 so that the blast head 12 and the guide member 16 have an appropriate positional relationship.

(Embodiment 2)
Hereinafter, a blasting device and a blasting method according to a second embodiment of the present invention will be described. Note that in this embodiment, the same description as that of the blasting device 1 according to the first embodiment will be omitted as appropriate.

Figure 6 is a top view showing the schematic configuration of the blasting device 1 according to the second embodiment. As shown in Figure 6, the blasting device 1 according to the second embodiment is provided with two guide members 16A, 16B that guide the abrasive material 17 discharged from the blast head 12 so that it reflects and collides with the inner pipe surface 31. Note that one or more of the two guide members 16A, 16B may be configured to be detachable from the blasting device 1. In the following description, when there is no particular distinction between the two guide members 16A, 16B, they are also simply referred to as guide members 16.

Guide member 16A reflects abrasive material 17, which is sprayed from blast head 12 toward the left side relative to the forward movement of blast head 12, by guide surface 161A so that the abrasive material 17 collides with pipe inner surface 31A on the left side in plan view as shown in FIG. 6. Guide member 16B reflects abrasive material 17, which is sprayed from blast head 12 toward the right side relative to the forward movement of blast head 12, by guide surface 161B so that the abrasive material 17 collides with pipe inner surface 31B on the right side in plan view as shown in FIG. 6.

This makes it possible to shorten the distance that at least some of the abrasive cleaning material 17 travels before colliding with the inner pipe surfaces 31A, 31B, compared to when the abrasive cleaning material 17 is jetted to the left and right of the forward direction and is reflected by a single guide member 16. This makes it possible to collide the abrasive cleaning material 17 with the inner pipe surfaces 31A, 31B while preventing the momentum of the abrasive cleaning material 17 from weakening, thereby further improving the abrasive cleaning efficiency.

Figure 7 is an explanatory diagram showing an example of the arrangement of two guide members 16A, 16B in a blasting device 1 according to embodiment 2.

The two guide members 16A and 16B are arranged in at least a part of the area where the angle of incidence Φ of the abrasive material 17 discharged from the blast head 12 when it flies toward and collides with the inner surface 31 of the pipe is 45 degrees or less in plan view as shown in FIG. 7.

Here, as shown in Fig. 7, the discharge position where the incident angle Φ of the abrasive cleaning material 17 discharged from the blast head 12 toward the pipe inner surface 31B is 45 degrees in a plan view is defined as discharge position P2. Also, as shown in Fig. 7, the discharge position where the incident angle Φ of the abrasive cleaning material 17 discharged from the blast head 12 toward the pipe inner surface 31A is 45 degrees in a plan view is defined as discharge position P3. In the rotation direction of the blast head 12, the radiation positions in the range from discharge position P2 to discharge position P3 are in the range of injection angles θ (incident angle Φ) where abrasive cleaning efficiency is poor.

By arranging the guide members 16A and 16B in at least a portion of the area where the angle of incidence Φ is 45 degrees or less, the abrasive material 17 discharged at a jet angle that results in poor abrasive cleaning efficiency can be reflected by the guide members 16A and 16B and collided with the inner pipe surfaces 31A and 31B, thereby improving the abrasive cleaning efficiency.

(Embodiment 3)
Hereinafter, a blasting device and a blasting method according to a third embodiment of the present invention will be described. Note that in this embodiment, the same description as that of the blasting device 1 according to the first embodiment will be omitted as appropriate.

Figure 8 is a top view showing the schematic configuration of the blasting device 1 according to embodiment 3.

As shown in FIG. 8, the blasting device 1 according to the third embodiment includes two guide members 16A, 16B arranged in a plan view so as to be point symmetrical about the rotation axis 121 of the blasting head 12. Note that one or more of the two guide members 16A, 16B may be configured to be detachable from the blasting device 1. In the following description, when there is no particular need to distinguish between the two guide members 16A, 16B, they will also be referred to simply as guide members 16.

Guide member 16A is emitted from the right side of rotation axis 121 of blast head 12 in the longitudinal direction of the pipe in a plan view as shown in FIG. 8, and is disposed in at least a part of the region where the angle of incidence Φ with respect to each of pipe inner surfaces 31A, 31B is 45 degrees or less. Guide member 16B is emitted from the left side of rotation axis 121 of blast head 12 in the longitudinal direction of the pipe in a plan view as shown in FIG. 8, and is disposed in at least a part of the region where the angle of incidence Φ with respect to each of pipe inner surfaces 31A, 31B is 45 degrees or less.

Here, as shown in FIG. 8, the discharge position where the incident angle Φ of the abrasive cleaning material 17 discharged from the blast head 12 toward the pipe inner surface 31B is 45 degrees in a plan view is defined as discharge position P2. Also, as shown in FIG. 8, the discharge position where the incident angle Φ of the abrasive cleaning material 17 discharged from the blast head 12 toward the pipe inner surface 31A is 45 degrees in a plan view is defined as discharge position P3. In the rotation direction of the blast head 12, the radiation position in the range from discharge position P2 to discharge position P3 is the range of injection angles θ (incident angle Φ) where the blasting efficiency is poor. In other words, this range is the range of injection angles where the blasting efficiency is poor, which exists to the right of the rotation axis 121 in the pipe longitudinal direction.

As shown in FIG. 8, the discharge position where the incident angle Φ of the abrasive material 17 discharged from the blast head 12 toward the pipe inner surface 31A is 45 degrees in a plan view is defined as discharge position P4. As shown in FIG. 8, the discharge position where the incident angle Φ of the abrasive material 17 discharged from the blast head 12 toward the pipe inner surface 31B is 45 degrees in a plan view is defined as discharge position P5. In the rotation direction of the blast head 12, the radiation position in the range from discharge position P4 to discharge position P5 is the range of injection angles θ (incident angle Φ) with poor blasting efficiency. In other words, this range is the range of injection angles with poor blasting efficiency that exists to the left of the rotation axis 121 in the pipe longitudinal direction.

In the blasting device 1 according to the third embodiment, the abrasive cleaning material 17 discharged from a range of injection angles with poor blasting efficiency, which exist on the right and left sides of the rotation axis 121 in the longitudinal direction of the pipe, can be reflected by the guide members 16A, 16B and collided with the pipe inner surfaces 31A, 31B. As a result, in the blasting device 1 according to the third embodiment, a larger amount of the abrasive cleaning material 17 discharged at an injection angle with poor blasting efficiency can be reflected by the guide members 16A, 16B and collided with the pipe inner surfaces 31A, 31B, thereby improving the blasting efficiency.

(Embodiment 4)
Hereinafter, a blasting device and a blasting method according to a fourth embodiment of the present invention will be described. Note that in this embodiment, the same description as that of the blasting device 1 according to the first embodiment will be omitted as appropriate.

Figure 9 is a top view showing the schematic configuration of the blasting device 1 according to embodiment 4.

As shown in FIG. 9, the blasting device 1 according to the fourth embodiment is provided with multiple guide members 16A-16F that guide the abrasive material 17 discharged from the blasting head 12 so that it reflects and strikes the inner pipe surface 31. Note that one or more of the multiple guide members 16A-16F may be configured to be detachable from the blasting device 1. In the following description, when the multiple guide members 16A-16F are not to be differentiated from one another, they are also referred to simply as guide members 16.

In the blasting device 1 according to the fourth embodiment, the guide member 16 for causing the abrasive material 17 to collide with the pipe inner surface 31A is divided into two guide members 16A and 16B. As shown in FIG. 9, in a plan view, the guide members 16A and 16B reflect the abrasive material 17 sprayed from the blast head 12 toward the left side relative to the forward movement of the blast head 12 so that it collide with the pipe inner surface 31A on the left side. The guide members 16A and 16B are shaped so that the abrasive material 17 reflected after colliding with one of the guide members 16 will collide with the pipe inner surface 31A without coming into contact with the other guide member 16.

In the blasting device 1 according to the fourth embodiment, the guide member 16 for causing the abrasive material 17 to collide with the pipe inner surface 31B is divided into four guide members 16C, 16D, 16E, and 16F. As shown in FIG. 9, the guide members 16C, 16D, 16E, and 16F reflect the abrasive material 17 ejected from the blasting head 12 toward the right side of the forward movement of the blasting head 12 in a plan view so that the abrasive material 17 collide with the pipe inner surface 31B on the right side. The guide members 16C, 16D, 16E, and 16F are shaped so that the abrasive material 17 reflected after colliding with any one of the guide members 16 will collide with the pipe inner surface 31B without coming into contact with the other guide members 16.

In the blasting device 1 according to the fourth embodiment, the guide member 16 that reflects the abrasive material 17 discharged toward the inner pipe surface 31 on the same side is divided into multiple parts. This allows each guide member 16 to be made smaller, so that the guide members 16 can be placed in steel pipes 3 with smaller inner diameters to improve the efficiency of abrasive cleaning.

(Embodiment 5)
Hereinafter, a blasting device and a blasting method according to a fifth embodiment of the present invention will be described. Note that in this embodiment, the same description as that of the blasting device 1 according to the fourth embodiment will be omitted as appropriate.

Figure 10 is a top view showing the schematic configuration of the blasting device 1 according to embodiment 5.

As shown in FIG. 10, the blasting device 1 according to the fifth embodiment is provided with a plurality of guide members 16A-16F similar to those of the blasting device 1 according to the fourth embodiment, and a plurality of guide members 16G-16L arranged in a point symmetrical manner with respect to the guide members 16A-16F with respect to the rotation axis 121 in a plan view. Note that one or more of the plurality of guide members 16A-16L may be configured to be detachable from the blasting device 1. In the following description, when the plurality of guide members 16A-16L are not to be particularly distinguished from one another, they are also referred to simply as guide members 16.

As shown in FIG. 10, in a plan view, the guide members 16G and 16H reflect the abrasive material 17 sprayed from the blast head 12 toward the right rear side relative to the forward movement of the blast head 12 so that it collides with the right-side pipe inner surface 31B. The guide members 16G and 16H are shaped so that the abrasive material 17 reflected after colliding with one of the guide members 16 collides with the pipe inner surface 31B without coming into contact with the other guide member 16.

Guide members 16I, 16J, 16K, and 16L reflect the abrasive material 17 sprayed from the blast head 12 toward the left rear side relative to the forward movement of the blast head 12 in a plan view as shown in FIG. 10 so that it collides with the left pipe inner surface 31B. Also, guide members 16I, 16J, 16K, and 16L are shaped so that the abrasive material 17 reflected after colliding with any one of the guide members 16 collides with the pipe inner surface 31A without coming into contact with the other guide members 16.

Note that in the blasting device 1 of embodiment 5, the multiple guide members 16A to 16F are similar to those in the blasting device 1 of embodiment 4, so a description thereof will be omitted.

In the blasting device 1 of embodiment 5, the guide member 16 is divided into multiple parts and provided at positions that are point symmetrical to the blasting device 1 of embodiment 4, so that many guide members 16 can be placed inside a steel pipe 3 with a smaller inner diameter, thereby improving the efficiency of blasting and cleaning.

1 Blast device 2 Floor 3 Steel pipe 4 Turning roll 5 Boom 11 Cart 12 Blast head 13 Upper boom 14 Lower boom 15 Belt conveyor 16 16A, 16B, 16C, 16D, 16E, 16F, 16G, 16H, 16I, 16J, 16K, 16L Guide member 17 Abrasive material 31, 31A, 31B Pipe inner surface 111 Wheel 121 Rotating shaft 131 Feeding port 151 Conveyor belt 152 Conveyor roll 161, 161A, 161B Guide surface

Claims (14)

A blast head that rotates around a rotation axis to release an abrasive;
A guide member that reflects the abrasive material discharged from the blast head with a guide surface and guides it to an inner pipe surface, which is an inner peripheral surface of a pipe material;
A blasting device for an inner surface of a pipe , comprising:
In a plan view, the X-axis is a direction perpendicular to both the rotation axis and the pipe longitudinal direction, which is the longitudinal direction of the pipe material, the Y-axis is the pipe longitudinal direction, and θ is an angle between the X-axis and a straight line connecting the rotation axis and the release position when the abrasive material is released from the blast head. This is a blasting device for the inner surface of a pipe, characterized in that at least a part of the shape of the guide surface is a shape that satisfies the relational expression dy/dx = -tan (π/4 - θ/2) in the XY plane . The blasting device for the inner surface of a pipe according to claim 1 , further comprising a plurality of said guide members. 3. The apparatus for blasting the inner surface of a pipe according to claim 2 , wherein at least one of the plurality of guide members is removable. 4. The blasting device for the inner surface of a pipe according to claim 1 , wherein the blast head and the guide member are supported by a same support member. The blast head is supported by a first support member;
4. The blasting device for the inner surface of a pipe according to claim 1 , wherein the guide member is supported by a second support member separate from the first support member. The blasting device for the inner surface of a pipe as described in claim 4, characterized in that the guide member is arranged in at least a part of the area where, when viewed in a plane, the angle between the direction of incidence of the abrasive material discharged from the blast head and the inner surface of the pipe is 45 degrees or less when the abrasive material collides with the inner surface of the pipe. The blasting device for the inner surface of a pipe as described in claim 5, characterized in that the guide member is arranged in at least a part of the area where, when viewed in a plane, the angle between the direction of incidence of the abrasive material discharged from the blast head and the inner surface of the pipe is 45 degrees or less when the abrasive material collides with the inner surface of the pipe. A method for blasting an inner surface of a pipe, comprising: rotating a blast head around a rotation axis; reflecting an abrasive material discharged from the blast head against a guide surface of a guide member and causing the abrasive material to collide with the inner surface of the pipe , which is an inner peripheral surface of the pipe material;
When viewed in a plane, the direction perpendicular to both the rotation axis and the pipe longitudinal direction, which is the longitudinal direction of the pipe material, is defined as the X-axis, the pipe longitudinal direction is defined as the Y-axis, and the angle between the X-axis and a straight line connecting the rotation axis and the release position when the abrasive material is released from the blast head is defined as θ, the shape of at least a part of the guide surface is a shape that satisfies the relational expression dy/dx = -tan (π/4 - θ/2) within the XY plane . The method for blasting the inner surface of a pipe according to claim 8 , characterized in that a plurality of said guide members are used. The method for blasting the inner surface of a pipe according to claim 9 , wherein at least one of the plurality of guide members is detachable. A method for blasting the inner surface of a pipe as described in any one of claims 8 to 10, characterized in that the blast head and the guide member supported by the same support member are inserted into the pipe material from one end side in the pipe longitudinal direction, which is the longitudinal direction of the pipe material. The blast head is supported by a first support member;
the guide member is supported by a second support member separate from the first support member,
The blast head is inserted into the pipe material from one end side in a pipe longitudinal direction, which is the longitudinal direction of the pipe material;
11. The method for blasting an inner surface of a pipe according to claim 8 , wherein the guide member is inserted into the pipe material from the other end side in the longitudinal direction of the pipe. The method for blasting the inner surface of a pipe as described in claim 11, characterized in that the guide member is arranged in at least a part of the area where, when viewed in a plane, the angle between the direction of incidence of the abrasive material discharged from the blast head and the inner surface of the pipe is 45 degrees or less when the abrasive material collides with the inner surface of the pipe. The method for blasting the inner surface of a pipe as described in claim 12, characterized in that the guide member is arranged in at least a part of the area where, when viewed in a plane, the angle between the direction of incidence of the abrasive material discharged from the blast head and the inner surface of the pipe is 45 degrees or less when the abrasive material collides with the inner surface of the pipe.

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