Thermal spraying device and thermal spraying method for long material

Abstract

The present invention provides an improved structure of a thermal spraying device for a long material and also provides a thermal spraying device and a thermal spraying method that are capable of stabilizing the quality of a thermally sprayed film with respect to a long material.　In a thermal spraying housing 12, a plurality of thermal spraying guns 18a, 18b, 18c are respectively disposed around an Al alloy pipe 20, which is a long material, at different positions in the axial direction, and are each configured to spray a prescribed thermal spraying material toward the Al alloy pipe 20 to form a thermally sprayed film on the outer surface of the Al alloy pipe 20. Additionally, roller devices 30, 32, which are each a restricting means for permitting movement of the Al alloy pipe 20 in the axial direction but restricting movement thereof in the direction perpendicular to the axial direction, are disposed respectively at locations situated outside the entrance port 24 for the Al alloy pipe 20 and outside the exit port 26 therefor in the thermal spraying housing 12, so that a thermal spraying operation with respect to the Al alloy pipe 20 is caused to proceed in a state in which the movement is restricted.

Description

Thermal spraying device and method for long materials

[0001] The present invention relates to a thermal spraying device and a thermal spraying method for a long material, and more particularly to a thermal spraying device and a thermal spraying method used to form a predetermined thermal sprayed coating in the axial direction of a long material.

[0002] Conventionally, as one of the surface modification techniques for long materials such as pipes and rods, a thermal spraying technique has been adopted in which a molten thermal spray material (particles) is sprayed onto the outer surface of such long materials to form a predetermined thermal spray coating in the axial direction. For example, Japanese Patent No. 6105561 discloses that a heat transfer tube made of an extruded or drawn aluminum alloy is sprayed with Zn or an Al-Zn alloy, and then subjected to a diffusion heat treatment to form a sacrificial corrosion protection layer consisting of a Zn diffusion layer. Also, Japanese Patent Laid-Open No. 57-67158 discloses a method for manufacturing metal-sprayed clad steel pipes with improved appearance and corrosion resistance by using multiple thermal sprayers arranged in a radial direction to spray a metal different from the base material onto the surface of a running base pipe to form a thermal spray coating.

[0003] In these thermal spraying techniques, a thermal spraying device for forming a thermal spray coating in the axial direction on the outer peripheral surface (outer surface) of a long material, such as a heat transfer tube or steel pipe, is used, which has a structure in which multiple thermal spray guns are arranged concentrically around the long material, with the long material as the center, and the multiple thermal spray guns simultaneously spray a predetermined thermal spray material (metal droplets) onto the outer peripheral surface of the long material at the same position in the axial direction. Therefore, such a thermal spraying device has the problem that, of the thermal spray material sprayed from the thermal spray guns onto the long material, any portion that does not adhere to the long material may adhere to the thermal spray gun located on the opposite side of the long material, rendering the thermal spray gun unusable. Another inherent problem is that the spray particles collide with each other, causing them to coarsen, which then adhere to the surface of the long material, resulting in poor quality of the formed thermal spray coating.

[0004] Furthermore, Japanese Utility Model Application Laid-Open Publication No. 60-136355 discloses, as one embodiment of an apparatus for spraying metal onto a long object, a thermal spraying apparatus in which a plurality of thermal spray guns are arranged so as to be offset in the circumferential direction of the long object to be sprayed, and also offset in the axial direction of the long object, so that the plurality of thermal spray guns are not arranged facing each other. This eliminates the need to consider the problems of adhesion of spray particles to the thermal spray guns and coarsening of the spray particles due to collisions between them.

[0005] However, in a thermal spraying device having a structure in which multiple thermal spray guns are arranged at offset positions in the axial and circumferential directions of the long object, as in Japanese Utility Model Application Laid-Open Publication No. 60-136355, the spray forces of the thermal spray material from the multiple directions of the multiple thermal spray guns cannot be mutually offset, and therefore the axial position of the long object in the thermal spraying zone changes due to the force of the spray material from the thermal spray guns, making it difficult to maintain a constant spraying distance from each thermal spray gun. Therefore, such changes in the spraying distance between the thermal spray gun and the long object change the temperature and velocity of the spray particles when they collide with the long object, which inherently risks causing variations in the quality, such as the characteristics and surface properties, of the thermal sprayed coating formed on the long object.

[0006] Patent No. 6105561 Publication of Japanese Patent Application Laid-Open No. 57-67158 Publication of Utility Model Application No. 60-136355

[0007] The present invention has been made in light of the above circumstances, and aims to provide an improved structure or technique for a thermal spraying device and method for thermal spraying long materials, and another aim is to provide a thermal spraying device and method that can stabilize the quality of the thermal sprayed coating on long materials.

[0008] In order to solve the above-mentioned problems, the present invention can be suitably implemented in various aspects as listed below, and the aspects described below can be adopted in any combination. It should be understood that the aspects and technical features of the present invention are not limited to those described below, but can be recognized based on the inventive idea disclosed in the entire description and drawings of the specification.

[0009] First, in a first aspect of the present invention for solving the above-mentioned problems, there is provided a thermal spraying device for forming a predetermined thermal spray coating on the outer surface of an elongated material that is moved axially in the thermal spraying zone using a plurality of thermal spray guns arranged in the thermal spraying zone, wherein the plurality of thermal spray guns are arranged around the elongated material at different axial positions in the thermal spraying zone, and the predetermined thermal spray material is sprayed from each thermal spray gun toward the elongated material to form the thermal spray coating; and the thermal spraying device for elongated materials is characterized in that regulating means are arranged at a position located outside the entry portion of the elongated material in the thermal spraying zone and at a position located outside the exit portion of the elongated material in the thermal spraying zone, respectively, to support the elongated material and allow movement of the elongated material in the axial direction but restrict movement in a direction perpendicular to the axis, and the thermal spraying operation on the elongated material is allowed to proceed with the movement of the elongated material restricted by the regulating means on both sides of the thermal spraying zone.

[0010] A second aspect of the present invention is characterized in that the elongated material is made to travel horizontally in the axial direction in the thermal spraying zone.

[0011] Furthermore, a third aspect of the present invention is characterized in that, among the multiple thermal spray guns, the thermal spray gun that sprays the thermal spray material from below toward the long material is positioned further inward in the thermal spray zone than the thermal spray gun positioned closest to the exit portion of the long material.

[0012] In addition, a fourth aspect of the present invention is characterized in that, among the plurality of thermal spray guns, the thermal spray gun that sprays the thermal spray material from below toward the elongated material is positioned further inward in the thermal spray zone than the thermal spray gun positioned closest to the entry point of the elongated material.

[0013] In a fifth aspect of the present invention, the plurality of thermal spray guns are arranged at equal angles in the circumferential direction of the elongated material.

[0014] A sixth aspect of the present invention is characterized in that the regulating means is composed of at least one roller arranged to support the long material.

[0015] Furthermore, a seventh aspect according to the present invention is characterized in that the regulating means is configured to include at least a first guide roller that supports the long material and two second guide rollers arranged on both sides of the long material.

[0016] An eighth aspect of the present invention is characterized in that the spray zone is constituted by a spray housing separated from the outside, and an entrance section and an exit section for the elongated material are respectively provided in the spray housing.

[0017] In addition, a ninth aspect according to the present invention is characterized in that the interior of the thermal spray housing is divided into a plurality of thermal spray chambers corresponding to the plurality of thermal spray guns, and the thermal spray material is sprayed from the corresponding thermal spray guns in each of the plurality of thermal spray chambers while the long material is moved in its axial direction.

[0018] In addition, a tenth aspect of the present invention is characterized in that the spray housing is provided with a gun insertion port for inserting and positioning the spray gun, while an exhaust port for sucking the atmosphere inside the spray housing is provided in the spray housing so as to face the spray gun inserted into the gun insertion port across the long material, so that overspray particles of the spray material sprayed from the spray gun that are not welded to the long material are sucked into the exhaust port.

[0019] Furthermore, an eleventh aspect of the present invention is characterized in that a gun insertion port for inserting and positioning the thermal spray gun is provided in each wall portion of the thermal spray housing corresponding to each of the multiple thermal spray chambers, while an exhaust port for sucking the atmosphere within the thermal spray chamber is provided in the wall portion of each thermal spray housing so as to face the thermal spray gun inserted into the gun insertion port across the long material, so that overspray particles of the thermal spray material sprayed from the thermal spray gun that are not welded to the long material are sucked into the exhaust port.

[0020] Furthermore, a twelfth aspect of the present invention is characterized in that the distance between the exit portion of the elongated material in the thermal spray zone and a regulating means arranged outside the exit portion of the elongated material is longer in the axial direction of the elongated material than the distance between the entry portion of the elongated material in the thermal spray zone and a regulating means arranged outside the entry portion of the elongated material.

[0021] A thirteenth aspect of the present invention is a method for thermally spraying a long material using the thermal spraying device described in any one of the first to twelfth aspects, characterized in that while the long material is moved in its axial direction, a predetermined thermal spray material is sprayed onto its outer surface from the plurality of thermal spray guns, thereby forming a thermal spray coating that covers the entire circumferential surface of the long material continuously in the axial direction of the long material.

[0022] A fourteenth aspect of the present invention also relates to a method for thermal spraying elongated materials, characterized in that, in a thermal spraying zone, a predetermined thermal spray material is sprayed onto the elongated material to be sprayed from a plurality of thermal spray guns arranged at different axial and circumferential positions of the elongated material to form a desired thermal spray coating on the outer surface of the elongated material, the elongated material is supported and moved axially while restricting its movement in a direction perpendicular to the axis to enter the thermal spraying zone, and the elongated material on which the thermal spray coating has been formed in the thermal spraying zone is supported on the exit side from the thermal spraying zone and moved axially while restricting its movement in a direction perpendicular to the axis to remove it from the thermal spraying zone.

[0023] In this way, in the thermal spraying device and method for long materials according to the present invention, a predetermined thermal spray material is forcefully sprayed from multiple thermal spray guns arranged at different positions in the axial direction (longitudinal direction) of the long material to be sprayed, and even if such long material is subjected to the pressing action of the spray pressure, the long material is supported by regulating means, etc., arranged on both sides of the thermal spraying zone, and movement in directions other than the axial direction can be effectively restricted.This makes it possible to maintain a constant spraying distance between the multiple thermal spraying guns and the long material, thereby advantageously stabilizing the quality of the thermal sprayed coating formed on the outer surface of the long material.

[0024] 1 is a conceptual diagram showing an example of a thermal spraying apparatus for elongated materials according to the present invention. It is an explanatory diagram of the A-A cross section in FIG. 1 showing the arrangement of thermal spray guns in the thermal spraying apparatus shown in FIG. 1 as viewed in the axial direction of the elongated material. It is an explanatory diagram showing an example of regulating means respectively arranged outside the entrance and exit portions of the elongated material in the thermal spraying housing in the thermal spraying apparatus shown in FIG. 1, where (a) is an explanatory diagram as viewed in the axial direction of the elongated material, and (b) is an explanatory plan view of the same. It is a conceptual diagram showing an example of an exhaust structure of the thermal spraying chamber formed in the thermal spraying housing in the thermal spraying apparatus for elongated materials according to the present invention. It is an explanatory diagram corresponding to FIG. 3(a) showing different examples of regulating means used in the thermal spraying apparatus for elongated materials according to the present invention, where (a) to (c) each show different examples of supporting and regulating forms of the elongated material using rollers.

[0025] In order to clarify the configuration of the present invention more specifically, a representative embodiment of the present invention will be described in detail below with reference to the drawings.

[0026] 1 is a schematic diagram of an example of a thermal spraying apparatus for long materials according to the present invention, showing a vertical cross section of a spray housing that forms the spray zone. The thermal spraying apparatus 10 has a spray housing 12, the interior of which forms the spray zone. The interior of the spray housing 12 is divided into three sections by two partition walls 14a, 14b, forming three spray chambers 16a, 16b, and 16c. In other words, the spray zone is formed by these three spray chambers 16a, 16b, and 16c.

[0027] Furthermore, spray guns 18a, 18b, 18c are disposed in the three spray chambers 16a, 16b, 16c formed in the spray housing 12, with their spray nozzles for the spray material (molten particles) opening into the respective spray chambers 16a, 16b, 16c. The three spray guns 18a, 18b, 18c are disposed in the spray housing 12 at different positions in the axial direction of the Al alloy tube 20, which is a long material.

[0028] 2, the three thermal spray guns 18a, 18b, 18c are arranged with a phase difference of 120° from one another in the circumferential direction of the Al alloy pipe 20 having a circular cross section. More specifically, in the central thermal spray chamber 16b of the thermal spray housing 12, the thermal spray gun 18b is arranged with its spray port open upward, and sprays the thermal spray material toward the Al alloy pipe 20 from below, in this case from directly below, upward. In the thermal spray chambers 16a, 16c located on both sides of the central thermal spray chamber 16b, the thermal spray guns 18a and 18c are arranged with a phase difference of 120° from the thermal spray gun 18b so as to be in opposite directions to each other in the circumferential direction of the Al alloy pipe 20. As shown in the figure, the thermal spray material is sprayed from the three thermal spray guns 18a, 18b, 18c so as to reach the entire circumferential surface of the Al alloy pipe 20.

[0029] Meanwhile, the Al alloy pipe 20 as a long material is extruded from a known extrusion device 22, as in the conventional case, and introduced into the spray housing 12 while still hot.While being moved axially within the spray housing 12, a predetermined spray material (e.g., Zn) is sprayed from the three spray guns 18a, 18b, 18c, so that a predetermined spray coating (e.g., Zn spray coating) is formed over the entire outer surface of the Al alloy pipe 20. In order to allow the Al alloy tube 20 to move axially, an entrance 24 (corresponding to the "entrance portion" according to the present invention) is provided in the wall of the spray chamber 16a of the spray housing 12, while an exit 26 (corresponding to the "exit portion" according to the present invention) is provided in the wall of the spray chamber 16c on the side where the Al alloy tube 20 is removed from the spray housing 12. Furthermore, the partition walls 14a, 14b that divide the inside of the spray housing 12 into three sections are each provided with communication ports 28, 28 through which the Al alloy tube 20 passes. In short, the Al alloy tube 20 can be moved or run axially through the entrance 24, communication ports 28, 28 and exit port 26 to pass through the spray housing 12.

[0030] Outside the inlet 24 of the sprayed housing 12, in other words, behind the inlet 24 in the direction of movement of the Al alloy tube 20, an inlet roller device 30 is arranged as a regulating means for supporting or holding the Al alloy tube 20 supplied from the extrusion device 22, while outside the outlet 26 of the sprayed housing 12, in other words, ahead of the outlet 26 in the direction of movement of the Al alloy tube 20, an outlet roller device 32 is arranged as a regulating means for supporting or holding the Al alloy tube 20 with a sprayed coating formed thereon that is taken out from the outlet 26. In other words, these two roller devices 30, 32 allow the Al alloy pipe 20 to move axially within the spray housing 12, in other words, within the spray zone, while restricting its movement perpendicular to the axis.Within this spray housing 12, a predetermined spray material is sprayed from three spray guns 18a, 18b, 18c, and a predetermined spray coating is formed on the outer surface of the Al alloy pipe 20.

[0031] 3(a) and 3(b), each of the roller devices 30, 32 is composed of a freely rotatable support roller 34a whose rotation axis is horizontal and perpendicular to the axis of the Al alloy tube 20, which receives the gravity of the Al alloy tube 20 and contacts and supports the Al alloy tube 20, and freely rotatable guide rollers 34b, 34b whose rotation axis is vertical and which are located on both sides of the Al alloy tube 20 at positions displaced in the axial direction of the Al alloy tube 20 from the support roller 34a. Therefore, even when the spray force of the thermal spray material from the thermal spray guns 18a, 18b, 18c acts on the Al alloy tube 20, the support roller 34a prevents downward movement of the Al alloy tube 20, and the two guide rollers 34b prevents left-right (lateral) displacement.

[0032] Since the Al alloy tube 20 is subjected to its own weight, which prevents it from moving upward, no rollers are provided here to restrict or prevent its upward movement. However, if necessary, it is also possible to provide rollers above the Al alloy tube 20 to restrict its upward movement.

[0033] In addition, here, the spray gun 18c installed in the spray chamber 16c on the outlet side of the spray housing 12 sprays the spray material onto the Al alloy pipe 20 from an obliquely upward direction, thereby forming the desired sprayed coating.In addition, taking into consideration the occurrence of defects due to contact with the formed sprayed coating, the two guide rollers 34b, 34b arranged on both sides of the Al alloy pipe 20 are each designed to form a small gap between them and the Al alloy pipe 20.

[0034] In addition, in order to avoid adverse effects caused by contact with the sprayed coating formed on the outer surface of the Al alloy pipe 20, the distance from the exit 26 of the exit roller device 32 is set to be longer in the axial direction of the Al alloy pipe 20 than the distance between it and the entrance 24 of the entrance roller device 30, and of the three rollers 34a, 34b, 34b that make up the exit roller device 32, the guide rollers 34b, 34b arranged on both sides of the Al alloy pipe 20 are configured so that they are located at a greater distance from the exit 26 than the support roller 34a, in other words, so that they are positioned further forward than the support roller 34a in the running direction of the Al alloy pipe 20.

[0035] In the thermal spraying device 10 configured as described above, the thermal spraying material is forcefully sprayed from multiple thermal spraying guns 18a, 18b, 18c at different axial positions of the long Al alloy pipe 20, and even if this large spraying force acts, the Al alloy pipe 20 is supported by an entry roller device 30 and an exit roller device 32 outside the entry entrance 24 and exit entrance 26 of the thermal spraying housing 12, respectively, and its movement in the up, down, left, and right directions, in other words, movement perpendicular to the axis, is essentially restricted.Therefore, the spraying distance between the thermal spraying guns 18a, 18b, 18c and the Al alloy pipe 20 can be kept essentially constant, which makes it easier to stabilize the quality of the thermal sprayed coating formed on the outer surface of the Al alloy pipe 20.

[0036] Furthermore, since the entry roller device 30 and the exit roller device 32 are both located outside the thermal spray housing 12, the thermal spray material (particles) sprayed from the thermal spray guns 18a, 18b, 18c do not adhere to them, and malfunctions in the roller devices 30, 32 due to the adhesion of such spray particles can be advantageously avoided.

[0037] Furthermore, in this exemplary embodiment, the thermal spray gun 18b that sprays the Al alloy pipe 20 from below (directly below) is arranged in the middle thermal spray chamber 16b, rather than in the first or last thermal spray chamber 16a or 16c, while in the thermal spray chambers 16a and 16c before and after that, the thermal spray guns 18a and 18c spray from diagonally above. As a result, the lifting of the Al alloy pipe 20 due to the spray from below is suppressed by the action of the two sprays from diagonally above, and the forces acting on the Al alloy pipe 20 by the spraying can be effectively canceled out or mitigated. In addition, contact between the delivery roller device 32 and the thermal spray coating formed on the outer surface of the Al alloy pipe 20 immediately after spraying can be avoided as much as possible, which advantageously prevents problems such as damage or peeling of the thermal spray coating due to rubbing, etc.

[0038] Furthermore, the interior of the spray housing 12 is divided by partitions 14a, 14b to form multiple spray chambers 16a to 16c, and spray guns 18a to 18c are arranged in each spray chamber.This makes it possible to arrange the spray guns close to each other in the axial direction of the Al alloy tube 20, allowing the device to be made more compact.In addition, the distance between the entry roller device 30 and the exit roller device 32, which are arranged on both sides of the spray housing 12, can be narrowed, making it possible to more stabilize the support of the Al alloy tube 20 within the spray housing 12, in other words, in the spray zone.

[0039] Each of the spray chambers 16a to 16c defined within the spray housing 12 is preferably configured to have a gun insertion port 40 and an exhaust port 42 located opposite each other on the wall of the spray housing 12 corresponding to the chamber, as shown in Figure 4. Specifically, an annular gap is formed between the edge of each gun insertion port 40 and the outer periphery of the spray gun 18a to 18c inserted therein, allowing air to be introduced into the spray chamber 16a to 16c from the outside through this gap. The exhaust port 42 is provided on the wall of the spray housing 12 so as to face the spray gun 18a to 18c inserted and positioned in the gun insertion port 40, with the Al alloy tube 20 between them. An exhaust hood 44 connected to a suction device (not shown) is attached to the outer surface of the spray housing 12 to cover the exhaust port 42.

[0040] By operating a suction device (not shown), the atmosphere inside each of the thermal spray chambers 16 a to 16 c is sucked into the exhaust port 42, while external air is taken into each of the thermal spray chambers 16 a to 16 c through the annular gap between the gun insertion port 40 and the thermal spray guns 18 a to 18 c. As a result, an intake airflow is generated in each of the thermal spray chambers 16 a to 16 c, flowing from the annular gap formed around the thermal spray guns 18 a to 18 c toward the exhaust port 42. Overspray particles of the thermal spray material sprayed from each of the thermal spray guns 18 a to 18 c that have not been welded to the Al alloy tube are carried by the intake airflow and advantageously expelled outside each of the thermal spray chambers 16 a to 16 c through the exhaust port 42. This makes it possible to prevent the thermal spray material from adhering to and accumulating on the inner wall surface of the thermal spray housing 12. The entire thermal spraying device 10, particularly at least the entire thermal spraying housing 12, is housed in a booth that can prevent foreign matter from entering from the outside. This, of course, ensures that no foreign matter is contained in the air that is drawn into each of the thermal spraying chambers 16a to 16c through the annular gaps around each of the thermal spraying guns 18a to 18c.

[0041] Although typical embodiments of the present invention have been described above in detail, it should be understood that these are merely examples, and that the present invention should not be construed as being limited in any way by the specific descriptions of such embodiments.

[0042] For example, the long material to be sprayed is not limited to pipe material such as the illustrated Al alloy pipe 20, but can also be rod material or wire material, and the cross-sectional outer shape can be any of various known outer shapes such as circular or elliptical. Furthermore, the material of the long material (20) and the material of the spray material sprayed from the spray guns 18a to 18c can be various known materials such as metal, ceramics, plastic, cermet, etc. Furthermore, the spraying method of the spray guns (18a to 18c) can be various known spraying methods such as arc spraying, flame spraying, plasma spraying, laser spraying, etc., and the present invention is applicable to spraying devices that use these known spraying methods.

[0043] Furthermore, the number of installed thermal spray guns may be three (18a to 18c) as shown in the example, or may be two, four, or more. It is desirable that the interior of the thermal spray housing (12) be divided by partition walls (14a, 14b...) to form thermal spray chambers (16a, 16b, 16c...) corresponding to each thermal spray gun (18a, 18b, 18c...). However, it is not necessary to divide the interior of a single thermal spray housing 12 by partition walls (14a, 14b...) to form each thermal spray chamber (16a, 16b, 16c...). It is also possible to form each thermal spray chamber using an individually independent thermal spray chamber. Furthermore, if the thermal spray guns can be positioned sufficiently apart in the axial direction of the elongated material (20), it may be possible to eliminate the need for a thermal spray chamber corresponding to each thermal spray gun.

[0044] Furthermore, any regulating means can be used for the inlet and outlet sides of the spray zone (spray housing 12) as long as it is designed to regulate the movement of the long material (Al alloy tube 20) moved axially in a direction perpendicular to the axis.For example, it may be a low-friction sliding member equipped with a groove or through hole that can slidably receive the long material, but generally, as shown in the example, a roller device (30, 32) that uses rollers to support and hold the long material will be advantageously used.

[0045] The regulating means (30) on the entrance side of the thermal spraying zone (12) and the regulating means (32) on the exit side of the thermal spraying zone (12) may have the same structure or different structures.

[0046] Furthermore, when the elongated material (20) is introduced into the thermal spraying zone (12) in a high temperature state, it is of course desirable that the regulating means on the entrance side of the thermal spraying zone be made of a material that can withstand such high temperatures (heat resistant), and furthermore, it is desirable that the regulating means (32) on the exit side of the thermal spraying zone be made of a material with a low friction coefficient, such as a graphite-based material, so that the thermal sprayed coating formed on the outer surface of the elongated material (20) is not damaged.

[0047] Furthermore, in the illustrated embodiment, the long material (Al alloy pipe 20) is introduced into the thermal spraying device 10 while still hot after being extruded from the extrusion device 22. However, if this is not the case, it is also possible to improve the adhesion of the thermal spray coating by subjecting the long material (20) to pre-treatments such as (a) heat treatment using an induction annealer, (b) blasting treatment (laser blasting, sand blasting, etc.), or (c) other known treatments that can contribute to improving adhesion, prior to thermal spraying.

[0048] In addition, even in devices that use rollers as regulating means, in addition to the roller devices 30 and 32 that are formed by combining three rollers 34a, 34b, and 34b as shown in the example, devices that use rollers of various known structures can be adopted, and for example, various rollers (devices) such as those shown in Figures 5(a) to (c) can be used.

[0049] 5, (a) shows a structure in which two guide rollers 52, 52 are arranged in a V-shape to contact and support the tubular material 50 as it is moved axially. Also, (b) shows a structure in which the tubular material 50 is supported by a grooved roller 54 having a V-shaped cross-sectional groove 54a on its outer circumferential surface. Furthermore, (c) shows a pinch roller structure in which a pair of arc-shaped grooved rollers 56, 56 are used to pinch, contact, and hold the tubular material 50. By employing such a pinch roller structure, it is possible to accommodate tubular materials 50 of various shapes by varying the spacing between the rollers 56, 56 according to the outer shape (external dimensions) of the tubular material 50, as shown in the figure.

[0050] Although not listed here, the present invention can be implemented in various forms with various changes, modifications, improvements, etc. based on the knowledge of those skilled in the art, and it should be understood that all such embodiments fall within the scope of the present invention as long as they do not deviate from the spirit of the present invention.

[0051] REFERENCE SIGNS LIST 10 Thermal spraying device 12 Thermal spraying housing 14a, 14b Partition wall 16a, 16b, 16c Thermal spraying chamber 18a, 18b, 18c Thermal spraying gun 20 Al alloy tube 22 Extrusion device 24 Inlet 26 Outlet 28 Communication port 30, 32 Roller device 34a Support roller 34b Guide roller 40 Gun insertion port 42 Exhaust port 50 Pipe material 52 Guide roller 54 Grooved roller 54a Groove 56 Roller

Claims

1. A thermal spraying device for forming a predetermined thermal spray coating on the outer surface of a long material that is moved axially in the thermal spraying zone using a plurality of thermal spray guns arranged in the thermal spraying zone, wherein the plurality of thermal spray guns are arranged around the long material at different axial positions in the thermal spraying zone, and the predetermined thermal spray material is sprayed from each thermal spray gun toward the long material to form the thermal spray coating, and wherein regulating means are arranged at a position located outside the entry part of the long material in the thermal spraying zone and a position located outside the exit part of the long material in the thermal spraying zone, respectively, to support the long material and allow movement of the long material in the axial direction but regulate movement in a direction perpendicular to the axis, and the thermal spraying operation on the long material can be carried out with the movement of the long material regulated by the regulating means on both sides of the thermal spraying zone.

2. The thermal spraying device for elongated materials according to claim 1, wherein the elongated material is made to travel horizontally in the axial direction in the thermal spraying zone.

3. A thermal spraying device for long materials as described in claim 2, characterized in that among the multiple thermal spraying guns, the thermal spraying gun that sprays the thermal spraying material from below toward the long material is positioned further inward in the thermal spraying zone than the thermal spraying gun positioned closest to the exit portion of the long material.

4. A thermal spraying device for long materials as described in claim 2, characterized in that among the multiple thermal spraying guns, the thermal spraying gun that sprays the thermal spraying material from below toward the long material is positioned further inward in the thermal spraying zone than the thermal spraying gun positioned closest to the entry point of the long material.

5. The thermal spraying device for elongated materials according to claim 1, wherein the plurality of thermal spraying guns are arranged at equal angles in the circumferential direction of the elongated material.

6. The thermal spraying device for elongated materials according to claim 1, wherein said regulating means comprises at least one roller arranged to support said elongated material.

7. A thermal spraying device for elongated materials as described in claim 6, characterized in that the regulating means is configured to include at least a first guide roller that supports the elongated material and two second guide rollers arranged on both sides of the elongated material.

8. A thermal spraying device for elongated materials as described in claim 1, characterized in that the thermal spraying zone is constituted by a thermal spraying housing separated from the outside, and an entrance section and an exit section for the elongated material are respectively provided in the thermal spraying housing.

9. A thermal spraying device for elongated materials as described in claim 8, characterized in that the interior of the thermal spray housing is divided into a plurality of thermal spraying chambers corresponding to the plurality of thermal spraying guns, and the thermal spraying material is sprayed from the corresponding thermal spraying guns in each of the plurality of thermal spraying chambers while the elongated material is moved axially.

10. A thermal spraying device for long materials as described in claim 8, characterized in that the thermal spray housing is provided with a gun insertion port for inserting and positioning the thermal spray gun, and an exhaust port for sucking the atmosphere inside the thermal spray housing is provided in the thermal spray housing so as to face the thermal spray gun inserted into the gun insertion port across the long material, so that overspray particles of the thermal spray material sprayed from the thermal spray gun that are not welded to the long material are sucked into the exhaust port.

11. A thermal spraying device for long materials as described in claim 9, characterized in that a gun insertion port for inserting and positioning the thermal spray gun is provided in the wall of the thermal spray housing corresponding to each of the multiple thermal spray chambers, while an exhaust port for sucking the atmosphere inside the thermal spray chamber is provided in the wall of each thermal spray housing so as to face the thermal spray gun inserted into the gun insertion port across the long material, so that overspray particles of the thermal spray material sprayed from the thermal spray gun that are not welded to the long material are sucked into the exhaust port.

12. A thermal spraying device for elongated materials as described in claim 1, characterized in that the distance between the regulating means arranged outside the exit portion of the elongated material in the thermal spraying zone and the exit portion is longer in the axial direction of the elongated material than the distance between the regulating means arranged outside the entry portion of the elongated material in the thermal spraying zone and the entry portion.

13. A method for thermally spraying a long material using the thermal spraying device of any one of claims 1 to 12, characterized in that while the long material is moved in its axial direction, a predetermined thermal spray material is sprayed onto its outer surface from the plurality of thermal spray guns, thereby forming a thermal spray coating that covers the entire circumferential surface of the long material continuously in the axial direction of the long material.

14. A method for thermal spraying elongated materials, comprising the steps of: spraying a predetermined thermal spray material onto an elongated material to be sprayed in a thermal spraying zone from a plurality of thermal spray guns arranged at different axial and circumferential positions of the material, respectively, to form a desired thermal spray coating on the outer surface of the elongated material; supporting the elongated material and restricting its movement in a direction perpendicular to its axis while moving it axially to enter the thermal spraying zone; and supporting the elongated material on which the thermal spray coating has been formed in the thermal spraying zone on the exit side from the thermal spraying zone while restricting its movement in a direction perpendicular to its axis while moving it axially to remove it from the thermal spraying zone.

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