JP7467066B2 - Welding device and method for controlling the same - Google Patents

Description

This disclosure relates to a welding device and a method for controlling the welding device.

Some furnace walls used in boilers use heat transfer panels in which long heat transfer tubes through which water and steam flow and plate-shaped fins are alternately connected by welding. In order to ensure the corrosion resistance of the heat transfer tubes, it is known to spirally weld a corrosion-resistant material to the surface of the heat transfer tube (see, for example, Patent Document 1 (paragraph 0072, etc.)). Patent Document 1 discloses that a corrosion-resistant layer is formed around the entire circumference of the piping by spirally welding the entire circumference of the tube by feeding a TIG welding torch while rotating the tube.

JP 2018-189282 A

In the spiral welding disclosed in Patent Document 1, the welding torch moves relative to the long heat transfer tube, so that the distance between the welding torch and the heat transfer tube is likely to vary at each position along the direction of the welding torch's movement. If the distance between the welding torch and the heat transfer tube or the angle with the welding torch varies, it becomes impossible to precisely manage the positional relationship between the welding torch and the heat transfer tube, which causes variations in the welding condition at each position along the length of the heat transfer tube, and it may not be possible to meet the welding specifications that set the tolerances for the buildup thickness, buildup surface roughness, etc.

The present disclosure has been made in consideration of these circumstances, and aims to provide a welding device and a control method for the welding device that can perform spiral overlay welding on the outer surface of a heat transfer tube while appropriately satisfying welding specifications such as overlay thickness and overlay surface roughness.

A welding device according to one aspect of the present disclosure performs overlay welding on the outer peripheral surface of a cylindrical heat transfer tube arranged along an axis, and includes a movement mechanism that moves the heat transfer tube along the axis, a rotation mechanism that rotates the heat transfer tube about the axis, an overlay welding mechanism that is fixed in position with respect to an installation surface on which the welding device is installed and that welds the outer peripheral surface of the heat transfer tube while supplying welding material to the outer peripheral surface of the heat transfer tube that passes through a predetermined welding position, and a control unit that controls the movement mechanism, the rotation mechanism, and the overlay welding mechanism, and the control unit controls the overlay welding mechanism to perform helical overlay welding on the outer peripheral surface of the heat transfer tube while the movement mechanism moves the heat transfer tube along the axis and the rotation mechanism rotates the heat transfer tube about the axis.

A control method for a welding device according to one aspect of the present disclosure is a control method for a welding device that performs overlay welding on the outer peripheral surface of a cylindrical heat transfer tube arranged along an axis, the welding device comprising a movement mechanism that moves the heat transfer tube along the axis, a rotation mechanism that rotates the heat transfer tube about the axis, and an overlay welding mechanism that is fixed to an installation surface on which the welding device is installed and that supplies welding material to the outer peripheral surface of the heat transfer tube that passes through a predetermined welding position, and includes a control step of controlling the welding device so that the overlay welding mechanism performs helical overlay welding on the outer peripheral surface of the heat transfer tube while the movement mechanism moves the heat transfer tube along the axis and the rotation mechanism rotates the heat transfer tube about the axis.

The present disclosure provides a welding device and a control method for the welding device that can perform spiral overlay welding on the outer surface of a heat transfer tube while appropriately satisfying welding specifications such as overlay thickness and overlay surface roughness.

1 is a vertical cross-sectional view of a gasification furnace included in a gasification furnace facility according to an embodiment of the present disclosure. FIG. FIG. 2 is a cross-sectional view showing a schematic configuration of the gasification furnace wall shown in FIG. 1 . FIG. 2 is an enlarged cross-sectional view showing a schematic configuration of the gasification furnace wall shown in FIG. 1 . FIG. 2 is a side view of a welding device according to an embodiment of the present disclosure, illustrating a state in which overlay welding has begun on an outer peripheral surface of a heat transfer tube. FIG. 2 is a side view of a welding device according to an embodiment of the present disclosure, illustrating a state in which overlay welding is being performed on an outer peripheral surface of a heat transfer tube. FIG. 2 is a side view of a welding device according to an embodiment of the present disclosure, illustrating a state in which overlay welding on an outer peripheral surface of a heat transfer tube has been completed. FIG. 6 is a partially enlarged view of the welding device shown in FIG. 5 . 8 is a cross-sectional view of the welding device shown in FIG. 7 taken along the line AA, showing a first lower support part. 8 is a cross-sectional view of the welding device shown in FIG. 7 taken along the line BB, showing a second lower support portion and an upper support mechanism. 8 is a cross-sectional view of the welding device shown in FIG. 7 taken along the line CC, showing a third lower support portion. 10A and 10B are diagrams illustrating a modified example of the upper support mechanism shown in FIG. 9 . FIG. 5 is a perspective view showing an internal structure of the movable carriage shown in FIG. 4 . FIG. 5 is a schematic diagram showing the cooling mechanism shown in FIG. 4 . 8 is a cross-sectional view taken along the line DD of the overlay welding mechanism shown in FIG. 7, showing a state in which the measurement mechanism measures a heat transfer tube that is not overlay welded. FIG. 8 is a cross-sectional view taken along the line DD of the overlay welding mechanism shown in FIG. 7, showing a state in which the measurement mechanism measures the heat transfer tube on which overlay welding has been performed. FIG. FIG. 5 is a schematic diagram showing a control configuration of the welding apparatus shown in FIG. 4 . 10A and 10B are diagrams showing modified examples of the second lower support portion and the upper support mechanism shown in FIG. 9 .

Hereinafter, a welding apparatus and a method for controlling the welding apparatus according to an embodiment of the present disclosure will be described with reference to the drawings. The welding apparatus of this embodiment is an apparatus for overlay welding, which cools the heat transfer tube itself and its surroundings by circulating cooling water (cooling medium) inside a cylindrical heat transfer tube during overlay welding, and overlays a welding material on the outer peripheral surface of the heat transfer tube to improve corrosion resistance and heat resistance.
In the following description, the terms "upper" and "lower" refer to upper and lower in the vertical direction.

The heat transfer tube with the welding material overlay welded by the welding device 200 of this embodiment is connected to, for example, a plurality of plate materials by welding to form a heat transfer panel. The heat transfer panel is disposed, for example, inside a boiler furnace or inside a gasification furnace. Below, a gasification furnace will be described with reference to the drawings as an example in which a heat transfer panel using a heat transfer tube with the welding material overlay welded is disposed. Figure 1 is a vertical cross-sectional view of a gasification furnace according to one embodiment of the present disclosure.

The gasifier 101 shown in FIG. 1 is a device that generates a generated gas that mainly contains hydrogen and carbon monoxide in an integrated coal gasification combined cycle (IGCC). For example, a carbon-containing solid fuel such as coal is used as the fuel supplied to the gasifier 101, and pulverized coal that has been pulverized into fine particles by a coal mill (not shown) is supplied. An air combustion method that uses air as the main oxidizer as a combustion method for generating combustible gas (generated gas) from fuel is used. The generated gas generated by the gasifier 101 is supplied to the combustor of a gas turbine that rotates and drives a generator.

As shown in FIG. 1, the gasifier 101 is formed to extend in the vertical direction, and pulverized coal and oxygen are supplied to the lower vertical side, and the gasified product gas flows from the lower vertical side to the upper vertical side. The gasifier 101 has a pressure vessel 110 and a gasifier wall 111 provided inside the pressure vessel 110. A heat transfer panel including a heat transfer tube T is used as the gasifier wall 111.

The gasifier 101 forms an annulus section 115 in the space between the pressure vessel 110 and the gasifier wall 111. The gasifier 101 also forms a combustor section 116, a diffuser section 117, and a reductor section 118 in the space inside the gasifier wall 111, in that order from the lower side in the vertical direction (i.e., the upstream side in the flow direction of the generated gas).

The pressure vessel 110 is formed in a cylindrical shape with a hollow space inside, with a gas exhaust port 121 formed at the upper end and a slag hopper 122 formed at the lower end (bottom). The gasification furnace wall 111 is formed in a cylindrical shape with a hollow space inside, with its wall surface facing the inner surface of the pressure vessel 110. In this embodiment, the pressure vessel 110 is, for example, cylindrical, and the diffuser section 117 of the gasification furnace wall 111 is also formed in, for example, a cylindrical shape. The gasification furnace wall 111 is connected to the inner surface of the pressure vessel 110 by a support member (not shown).

The gasification furnace wall 111 separates the interior of the pressure vessel 110 into an internal space 154 and an external space 156. The cross-sectional shape of the gasification furnace wall 111 changes at the diffuser section 117 between the combustor section 116 and the reductor section 118. The gasification furnace wall 111 has an upper end portion on the vertically upper side connected to the gas exhaust port 121 of the pressure vessel 110, and a lower end portion on the vertically lower side provided with a gap between it and the bottom of the pressure vessel 110.

Water is stored in a slag hopper 122 formed at the bottom of the pressure vessel 110, and the lower end of the gasification furnace wall 111 is submerged in the stored water, sealing the inside and outside of the gasification furnace wall 111. Burner devices 126, 127 are inserted into the gasification furnace wall 111, and a syngas cooler 102 is arranged in the internal space 154.

The annulus 115 is a space formed inside the pressure vessel 110 and outside the gasification furnace wall 111, that is, the external space 156, and nitrogen, an inert gas separated by an air separation facility (not shown), is supplied through a nitrogen supply line (not shown). Therefore, the annulus 115 becomes a space filled with nitrogen. In addition, an in-furnace pressure equalizing pipe (not shown) is provided near the vertical upper portion of the annulus 115 to equalize the pressure inside the gasification furnace 101. The in-furnace pressure equalizing pipe is provided to communicate the inside and outside of the gasification furnace wall 111, and approximately equalizes the pressure difference between the inside (combustor section 116, diffuser section 117, and reductor section 118) and the outside (annulus section 115) of the gasification furnace wall 111 to within a predetermined pressure.

The combustor section 116 is a combustion chamber that partially combusts the pulverized coal and char (unreacted coal and ash) with air, and a combustion device consisting of multiple burner devices 126 is arranged on the gasification furnace wall 111 in the combustor section 116. The high-temperature combustion gas produced by burning a portion of the pulverized coal and char in the combustor section 116 passes through the diffuser section 117 and flows into the reductor section 118.

The reductor section 118 is a space where pulverized coal is supplied to the combustion gas from the combustor section 116, which is maintained at a high temperature required for the gasification reaction, and where partial oxidation combustion is performed to break down the pulverized coal into volatile matter (carbon monoxide, hydrogen, low hydrocarbons, etc.), which is gasified and generates a generated gas. A combustion device consisting of multiple burner devices 127 is arranged on the gasification furnace wall 111 in the reductor section 118.

Next, the gasification furnace wall 111 will be described with reference to the drawings. FIG. 2 is a cross-sectional view showing the schematic configuration of the gasification furnace wall 111 shown in FIG. 1. FIG. 3 is an enlarged cross-sectional view showing the schematic configuration of the gasification furnace wall 111 shown in FIG. 1.

The horizontal cross-sectional shape of the gasification furnace wall 111 is a polygonal or cylindrical tube shape, but the embodiment shown in FIG. 3 is an example of a cylindrical shape, and multiple water-cooled wall tubes 142 are provided in the cylindrical wall portion 140. In other words, multiple water-cooled wall tubes 142 are provided in a concentric arrangement in part of the wall portion 140.

The gasification furnace 101 has a cooling water circulation mechanism (not shown) that circulates a refrigerant (cooling water such as feed water or steam) inside the water-cooled wall tubes 142. The multiple water-cooled wall tubes 142 extend vertically throughout the entire gasification furnace 101, and extend vertically up and down without being cut off, and are arranged side by side in the circumferential direction to form the wall portion 140 of the gasification furnace 101.

As shown in FIG. 3, at least a portion of the water-cooled wall tube 142 has a heat transfer tube T and a weld bead WB provided on the outer periphery of the heat transfer tube T. The heat transfer tube T is a pipe through which cooling water flows. The weld bead WB is disposed around the entire circumferential direction of the heat transfer tube T and covers the outer periphery of the heat transfer tube T. The weld bead WB is formed by overlay welding on the outer periphery of the heat transfer tube T using a welding device 200 described later.

The wall portion 140 has a plate material (fin) 166 between the water-cooled wall tubes 142. In this embodiment, the wall portion 140 has a cylindrical shape formed by arranging a plurality of water-cooled wall tubes 142 concentrically and blocking the space between the water-cooled wall tubes 142 with a plate material 166. The wall portion 140 also has a welded portion 168 that connects the weld bead WB of the water-cooled wall tube 142 to the plate material 166. The welded portion 168 is formed at the end of the contact portion between the welded bead WB and the plate material 166 on the inner space 154 side and the end on the outer space 156 side. The welded portion 168 is formed by welding, and connects the welded bead WB of the water-cooled wall tube 142 to the plate material 166 by being in close contact with both the welded bead WB and the plate material 166.

The gasification furnace wall 111 has the heat transfer tube T made of a first material and the weld bead WB made of a second material. The plate material 166 and the welded portion 168 may also be made of the second material. The first material and the second material are metals. The second material is a material that is more corrosion resistant (corrosion resistant) and has higher heat resistance than the first material. The gasification furnace wall 111 can protect the heat transfer tube T by forming the weld bead WB from a material that is more corrosion resistant and has higher heat resistance than the heat transfer tube T.

Specifically, in the internal space 154 inside the gasification furnace wall 111, flammable gas flows, and the oxidizer (gas containing oxygen) and fuel are partially combusted, resulting in gasified gas that flows and reaches a high temperature. By covering the surface of the heat transfer tube T facing the internal space 154 with a weld bead WB, the heat transfer tube T can be protected from corrosion and high-temperature operating environments. In addition, if slag such as coal adheres to and falls off the heat transfer tube T, weld bead WB, and plate material 166 of the gasification furnace wall 111, causing temperature changes on the wall surface of the gasification furnace wall 111 and creating a temperature distribution in the heat transfer tube T and weld bead WB, the effect of the thermal expansion difference due to the difference in material becomes large, and localized thermal stress may become large, so the weld bead WB is formed from a material with high heat resistance.

Furthermore, the internal space 154 of the combustor section 116, diffuser section 117, and reductor section 118 of the gasification furnace wall 111 is a high-temperature atmosphere exceeding 1500°C, which tends to increase the temperature difference. For this reason, in this embodiment, the external space 156 side and the internal space 154 side of the gasification furnace wall 111 have the same shape that is symmetrical with respect to the plane connecting the axis of the heat transfer tube T and the center of the plate thickness of the plate material 166, so that even if a localized temperature distribution occurs, it is possible to suppress an increase in heat load due to differences in thermal expansion, thereby improving the durability of the gasification furnace wall 111.

Next, the welding device 200 that performs helical overlay welding on the outer peripheral surface of the heat transfer tube T will be described with reference to the drawings. FIG. 4 is a side view of the welding device 200 according to an embodiment of the present disclosure, showing a state in which overlay welding has started on the outer peripheral surface of the heat transfer tube T and a weld bead WB has begun to be formed. FIG. 5 is a side view of the welding device 200 according to an embodiment of the present disclosure, showing a state in which overlay welding has been performed on the outer peripheral surface of the heat transfer tube T to form a weld bead WB. FIG. 6 is a side view of the welding device 200 according to an embodiment of the present disclosure, showing a state in which overlay welding on the outer peripheral surface of the heat transfer tube T has been completed.

Figure 7 is a partially enlarged view of the welding device 200 shown in Figure 5. Figure 8 is a cross-sectional view of the welding device 200 shown in Figure 7 taken along the line A-A, showing the first lower support section 31. Figure 9 is a cross-sectional view of the welding device 200 shown in Figure 7 taken along the line B-B, showing the second lower support section 32 and the upper support mechanism 40. Figure 10 is a cross-sectional view of the welding device 200 shown in Figure 7 taken along the line C-C, showing the third lower support section 33. Figure 11 is a view showing a modified example of the upper support mechanism 40 shown in Figure 9. Figure 12 is a perspective view showing the internal structure of the movable carriage 10 shown in Figure 4.

The welding device 200 shown in Figures 4 to 6 is a device that forms a weld bead WB by spirally depositing welding material on the outer peripheral surface of a heat transfer tube T to the water-cooled wall tube 142 of the gasification furnace wall 111. As shown in Figures 4 to 6, the heat transfer tube T is a cylindrical tube disposed along an axis X that extends horizontally in the plane of the drawing. As shown in Figures 4 to 6, the welding device 200 includes a movable carriage 10, an overlay welding mechanism 20, a lower support mechanism 30, an upper support mechanism 40, a cooling mechanism 50, a measuring mechanism 60, a main body 70, an imaging unit 80, a display unit 85, and a control unit 90.

The welding device 200 positions the heat transfer tube T at a certain height from the installation surface S so that it is parallel to the installation surface S, and supports it with the lower support mechanism 30 and the upper support mechanism 40. The welding device 200 rotates the heat transfer tube T at a predetermined number of rotations around the axis X while moving the heat transfer tube T at a predetermined speed along the movement direction MD using the movable carriage 10. The welding device 200 performs overlay welding on the heat transfer tube T, which moves along the movement direction MD and rotates around the axis X, using the overlay welding mechanism 20 installed at a fixed position relative to the installation surface S above the paper surface.

In the state shown in FIG. 4, overlay welding is started on the outer peripheral surface of the heat transfer tube T, the range of the weld bead WB formed in a spiral shape increases as shown in FIG. 5, and overlay welding on the outer peripheral surface of the heat transfer tube T ends in the state shown in FIG. 6. By performing the operations shown in FIG. 4 to FIG. 6, the welding device 200 forms a weld bead WB in which the welding material is overlay welded in a spiral shape on the outer peripheral surface of the heat transfer tube T.

The movable carriage 10 is an example of a mechanism that moves the heat transfer tube T along the axis X at a predetermined speed while rotating the heat transfer tube T at a predetermined speed. As shown in FIG. 12, the movable carriage 10 includes a moving mechanism 11 that moves the heat transfer tube T along the axis X, and a rotating mechanism 12 that rotates the heat transfer tube T about the axis X.

As shown in FIG. 12, the moving mechanism 11 drives the moving motor 11a to rotate the first gear 11c connected to the drive shaft 11b in the same axial direction as the drive shaft 11b, and rotates the second gear 11d engaged with the first gear 11c. The second gear 11d rotates the third gear 11f connected via the connecting shaft 11e. The third gear 11f engages with a rack gear 71 provided on the main body 70 fixed to the installation surface S on which the welding device 200 is installed. Therefore, when the third gear 11f rotates, the carriage 11g of the moving mechanism 11 moves in the moving direction MD along the rail 72 of the main body 70. Here, the moving direction MD is a direction parallel to the axis X direction of the heat transfer tube T.

The heat transfer tube T is fixed to the movable carriage 10 by the rotation mechanism 12 in a state in which it can rotate around the axis X, and the outer peripheral surface of the heat transfer tube T is held by the fixing portion 12e so that it does not move in the direction of the axis X relative to the movement mechanism 11. Therefore, when the movement mechanism 11 moves along the axis X, the heat transfer tube T also moves along the axis X accordingly. In this way, the movement mechanism 11 moves the heat transfer tube T along the axis X by rotating the movement motor 11a. The drive of the movement motor 11a is controlled by a control signal transmitted from the control unit 90.

As shown in FIG. 12, the rotation mechanism 12 drives the rotation motor 12a to rotate the first gear 12c connected to the drive shaft 12b, and rotate the second gear 12d engaged with the first gear 12c. The second gear 12d is connected to a fixed part 12e that holds the outer peripheral surface of the heat transfer tube T and is fixed to the second gear 12d so as to be integral with the fixed part 12e, which is non-rotatably fixed to the second gear 12d. Therefore, when the second gear 12d rotates, the heat transfer tube T also rotates around the axis X.

In this way, the rotation mechanism 12 rotates the rotation motor 12a to rotate the heat transfer tube T around the axis X in a fixed direction at a predetermined number of rotations. The drive of the rotation motor 12a is controlled by a control signal transmitted from the control unit 90.

As shown in FIG. 7, the overlay welding mechanism 20 is a device that forms a spiral weld bead WB while supplying welding material to the outer peripheral surface of the heat transfer tube T that passes through a predetermined welding position P0 on the axis X. The overlay welding mechanism 20 is fixed to the installation surface S on which the welding device 200 is installed via the main body 70. The overlay welding mechanism 20 performs TIG (Tungsten Inert Gas) welding, for example, using a welding torch 21 having a tungsten electrode 21a. The overlay welding mechanism 20 applies a voltage to the tungsten electrode 21a and supplies a current according to a control signal transmitted from the control unit 90, and a welding current flows between the tip of the tungsten electrode 21a and the outer peripheral surface of the heat transfer tube T to form an arc and increase the temperature.

A welding wire (welding material) is supplied to the arc formed by the welding torch 21. A predetermined amount of welding wire is fed in response to a control signal transmitted from the control unit 90, and the welding wire is heated by Joule heat when a current is passed through the welding wire. The welding wire in this embodiment may be, for example, a corrosion-resistant material including a solid-solution strengthened nickel-based alloy such as Inconel (registered trademark) or a high chromium content alloy.

The overlay welding mechanism 20 is fixed to the main body 70, but the heat transfer tube T moves along the movement direction MD and rotates around the axis X. Therefore, the overlay welding mechanism 20 welds to the heat transfer tube T at a fixed position on the main body 70, and a corrosion-resistant material is overlaid and welded in a spiral shape onto the outer surface of the heat transfer tube T. In addition, because the overlay welding mechanism 20 is in a fixed position on the main body 70, the positional relationship between the welding torch 21 and the heat transfer tube T can be managed with high precision.

The lower support mechanism 30 is a mechanism that supports the heat transfer tube T from below, and is fixed to the installation surface S. The lower support mechanism 30 includes a first lower support portion 31, a second lower support portion 32, and a third lower support portion 33. The lower support mechanism 30 will be described below with reference to the drawings. FIG. 8 is a cross-sectional view of the welding device 200 shown in FIG. 7 taken along the line A-A, showing the first lower support portion 31. FIG. 9 is a cross-sectional view of the welding device 200 shown in FIG. 7 taken along the line B-B, showing the second lower support portion 32 and the upper support mechanism 40. FIG. 10 is a cross-sectional view of the welding device 200 shown in FIG. 7 taken along the line C-C, showing the third lower support portion 33.

The first lower support 31 supports the lower part of the heat transfer tube T at the position closest to the overlay welding mechanism 20, and is fixed to the main body 70 to which the overlay welding mechanism 20 is fixed. As shown in FIG. 8, the first lower support 31 has a pair of spheres (first spheres) 31a that contact two circumferential points on the outer peripheral surface of the lower side of the heat transfer tube T, and a holding part (first holding part) 31b that holds each of the pair of spheres 31a rotatably in any direction. The first lower support 31 supports the lower part of the heat transfer tube T by sandwiching it from two different positions in the circumferential direction with the pair of spheres 31a, thereby being able to hold the center position (position of the axis X) of the heat transfer tube T at a fixed position.

The second lower support part 32 is disposed adjacent to the first lower support part 31, and is disposed upstream (to the right of the drawing) of the first lower support part 31 in the movement direction MD of the heat transfer tube T along the axis X. As shown in FIG. 9, the second lower support part 32 has a pair of spheres (first spheres) 32a that contact two circumferential points on the outer peripheral surface of the lower side of the heat transfer tube T, and a holding part (first holding part) 32b that holds each of the pair of spheres 32a so that they can rotate in any direction. The second lower support part 32 supports the lower side of the heat transfer tube T by sandwiching it at two different positions in the circumferential direction with the pair of spheres 32a, thereby being able to hold the center position (position of the axis X) of the heat transfer tube T at a fixed position.

The third lower support portion 33 is disposed at a plurality of locations downstream (left side of the drawing) of the movement direction MD of the heat transfer tube T with respect to the first lower support portion 31, and at a plurality of locations upstream (right side of the drawing) of the movement direction MD of the heat transfer tube T with respect to the second lower support portion 32. As shown in FIG. 10, the third lower support portion 33 has a pair of spheres (first spheres) 33a that contact the outer peripheral surface of the lower side of the heat transfer tube T, or two circumferential locations of the outer peripheral surface of the lower side of the heat transfer tube T in a state where a weld bead WB is formed on the outer peripheral surface of the heat transfer tube T (water-cooled wall tube 142), and a holding portion (first holding portion) 33b that holds each of the pair of spheres 33a rotatably in any direction. The third lower support portion 33 supports the lower side of the heat transfer tube T by the pair of spheres 33a in a state where the lower side is sandwiched from two different positions in the circumferential direction, thereby being able to hold the center position (position of the axis X) of the heat transfer tube T at a fixed position.

The third lower support section 33 is provided with a height adjustment mechanism (switching mechanism) 33c that can adjust the distance in a direction perpendicular to the installation surface S of the tip position that supports the heat transfer tube T (up and down on the paper). The height adjustment mechanism 33c is a mechanism that can switch between a support state (state shown in FIG. 6) in which the sphere 33a is held at a position that supports the heat transfer tube T, and a retracted state (state shown in FIGS. 4 and 5) in which the sphere 33a is retracted to a position that does not support the heat transfer tube T. The height adjustment mechanism 33c is a mechanism that moves the tip position of the sphere 33a in a direction perpendicular to the installation surface S (up and down on the paper). The height adjustment mechanism 33c is a mechanism that expands and contracts vertically up and down due to the pressure of compressed air supplied from a compressed air source (not shown), for example, and manages the tip position of the sphere 33a with a stopper not shown.

The third lower support parts 33, which are arranged at multiple locations downstream of the first lower support part 31 in the movement direction MD of the heat transfer tube T, move the tip position of the sphere 33a downward to a retracted state by the height adjustment mechanism 33c so as not to come into contact when the movable carriage 10 moves in the movement direction MD. In the state shown in Figures 4 and 5, the movable carriage 10 is not passing through the third lower support part 33 arranged at the most downstream side of the movement direction MD of the heat transfer tube T, so the tip position of the sphere 33a is retracted to avoid contact with the movable carriage 10. On the other hand, in the state shown in Figure 6, the movable carriage 10 is passing through, so the tip position of the sphere 33a is in a supported state.

The third lower support parts 33, which are arranged at multiple locations upstream of the first lower support part 31 in the movement direction MD of the heat transfer tube T, move the tip position of the sphere 33a downward by the height adjustment mechanism 33c so as not to contact the cooling mechanism 50. In the state shown in FIG. 4, the cooling mechanism 50 is not passing through the third lower support part 33 arranged at the most upstream side of the movement direction MD of the heat transfer tube T, so the tip position of the sphere 33a is in a supported state. On the other hand, in the state shown in FIG. 5 and FIG. 6, the cooling mechanism 50 is passing through, so the tip position of the sphere 33a is in a retracted state to avoid contact with the cooling mechanism 50.

The upper support mechanism 40 is a mechanism that supports the heat transfer tube T from above, and is fixed to the main body 70 to which the overlay welding mechanism 20 is fixed. The upper support mechanism 40 supports the heat transfer tube T at a position upstream of the overlay welding mechanism 20 in the movement direction MD of the heat transfer tube T and close to the overlay welding mechanism 20, thereby suppressing fluctuations in the positional relationship between the welding torch 21 and the heat transfer tube T, such as the distance from the welding torch 21 of the overlay welding mechanism 20 to the heat transfer tube T and the angle with the welding torch 21.

Here, the upper support mechanism 40 is fixed to the main body 70, but other configurations are also possible. For example, the upper support mechanism 40 may not be fixed to the main body 70, but may be directly supported by the installation surface S by a support mechanism (e.g., a gate-shaped mechanism having a pair of support pillars extending upward from the sides of the second lower support part 32 and a beam connecting the pair of support pillars horizontally) provided directly on the installation surface S.

7 and 9, the upper support mechanism 40 has a sphere (second sphere) 40a that contacts the outer peripheral surface of the upper side of the heat transfer tube T, a holder (second holder) 40b that holds each of the spheres 40a so that they can rotate in any direction, and a height adjustment mechanism 40c. The height adjustment mechanism 40c is a mechanism that can adjust the distance in the perpendicular direction (up and down on the page) to the installation surface S of the tip position that supports the heat transfer tube T.

The height adjustment mechanism 40c is a mechanism that can switch between a support state (a state shown by a dashed line in FIG. 9) in which the sphere 40a is held in a position that supports the heat transfer tube T, and a retracted state (a state shown by a solid line in FIG. 9) in which the sphere 40a is retracted to a position that does not support the heat transfer tube T. The height adjustment mechanism 40c is a mechanism that moves the tip position of the sphere 33a along a direction perpendicular to the installation surface S (the vertical direction of the paper). The height adjustment mechanism 40c is, for example, a mechanism that expands and contracts in the vertical direction by the pressure of compressed air supplied from a compressed air source (not shown). After the heat transfer tube T is supported by the lower support mechanism 30, the height adjustment mechanism 40c switches the position of the sphere 40a from the retracted state to the support state by a control signal transmitted from the control unit 90. In addition, when the tip position of the sphere 40a is in the support state, it may be pressed from the upper side to the lower side by the pressure of compressed air supplied from the support state compressed air source (not shown) while retaining elasticity.

Next, the positional relationship between the overlay welding mechanism 20, the lower support mechanism 30, and the upper support mechanism 40 will be described with reference to FIG. 7. In FIG. 7, the position (welding position) on the axis X where the welding torch 21 of the overlay welding mechanism 20 performs overlay welding on the outer peripheral surface of the heat transfer tube T is designated as P0. Also, the position on the axis X where the sphere 31a of the first lower support part 31 of the lower support mechanism 30 supports the outer peripheral surface of the lower side of the heat transfer tube T where overlay welding is not being performed is designated as P1.

The position on the axis X where the sphere 33a of the third lower support part 33 of the lower support mechanism 30, which is arranged adjacent to the first lower support part 31 downstream in the moving direction MD, supports the outer peripheral surface of the lower side of the heat transfer tube T on which overlay welding has been performed, is defined as P2. The position on the axis X where the sphere 32a of the second lower support part 32 of the lower support mechanism 30 supports the outer peripheral surface of the lower side of the heat transfer tube T on which overlay welding has not been performed is defined as P3.

In FIG. 7, axis Y0 is an axis that passes through P0 and extends vertically, axis Y1 is an axis that passes through P1 and extends vertically, axis Y2 is an axis that passes through P2 and extends vertically, and axis Y3 is an axis that passes through P3 and extends vertically.

The distance in the axial X direction from P0 to P1 (first distance) is L1, the distance in the axial X direction from P0 to P2 (second distance) is L2, and the distance in the axial X direction from P1 to P3 is L3. Furthermore, the distance in the axial X direction from the position on the axial X where the sphere 40a of the upper support mechanism 40 supports the outer circumferential surface of the upper side of the heat transfer tube T where no overlay welding has been performed to P0 is L4. Here, L1, L2, L3, and L4 satisfy the relationship of the following formula (1).
L1<L3<L4<L2 (1)

As shown in formula (1), the distance L1 in the axial direction from P0 to P1 is shorter than the distance L2 in the axial direction from P0 to P2. Therefore, the first lower support part 31, which is arranged upstream of P0 in the moving direction MD of the heat transfer tube T, supports the heat transfer tube T from the lower side at a position P1 closer to the welding position P0 than the third lower support part 33, which is arranged downstream of the moving direction MD. The second lower support part 32, which is arranged upstream of P0 in the moving direction MD of the heat transfer tube T, supports the heat transfer tube T from the lower side at a position P3 slightly further upstream from the welding position P0 than the first lower support part 31. On the other hand, the third lower support part 33, which is arranged downstream of P0 in the moving direction MD of the heat transfer tube T, supports the state in which the weld bead WB is formed on the outer peripheral surface of the heat transfer tube T (water-cooled wall tube 142) from the lower side at a position P2 further downstream from the welding position P0 than the first lower support part 31.

Because there is no weld bead WB upstream of P0 in the moving direction MD, the outer peripheral surface of the heat transfer tube T where no welding has been performed is supported by P1 near the welding position P0 and by P3 in the vicinity, and fluctuations in the positional relationship between the welding torch 21 of the overlay welding mechanism 20 and the outer peripheral surface of the heat transfer tube T, such as the distance from the welding torch 21 to the heat transfer tube T and the angle with the welding torch 21, can be suppressed. In addition, downstream of the moving direction MD, the outer peripheral surface in a state where the overlay welding is performed and the weld bead WB is formed and has an uneven surface is supported at position P2 away from the welding position P0, suppressing the transmission of vibrations when the uneven surface passes through the third lower support part 33 to the overlay welding mechanism 20, and suppressing the effects of minute positional fluctuations of the axis X due to the thickness of the weld bead WB.

L1 is set, for example, to 10 mm or more and 100 mm or less. L1 is set to 10 mm or more to prevent contact between the high-temperature weld bead WB overlay welded at P0 and the first lower support portion 31. L1 is set to 100 mm or less to suppress fluctuations in the distance from the tip of the welding torch 21 to the outer peripheral surface of the heat transfer tube T at P0 and in the angle with the welding torch 21 by supporting the heat transfer tube T at a position close to P0.

L2 is set, for example, to 1000 mm or more and 2500 mm or less. L2 is set to 1000 mm or more in order to suppress the transmission of vibrations caused by the uneven shape of the weld bead WB formed on the outer surface of the heat transfer tube T when it passes through the third lower support portion 33 to the build-up welding mechanism 20 and to suppress the effects of minute positional fluctuations of the axis X due to the thickness distribution of the weld bead WB. In addition, L2 is set to 2500 mm or less because if the distance from P0 to P2 is too long, partial deflection occurs in the heat transfer tube T, and the heat transfer tube T cannot be stably supported.

As shown in formula (1), the distance L3 from P1 to P3 in the axial direction X and the distance L4 from P0 to P3 are longer than L1 and shorter than L2. Since the second lower support part 32 and the upper support mechanism 40 are each positioned upstream of P0 in the movement direction MD, and the weld bead WB has no uneven shape, the effect of vibration on the build-up welding mechanism 20 is small even if the distance is shorter than L2. In addition, by supporting the heat transfer tube T at a position closer to the welding position than the third lower support part 33, it is possible to suppress fluctuations in the distance from the tip of the welding torch 21 to the outer peripheral surface of the heat transfer tube T and in the angle with the welding torch 21.

L3 is set, for example, to 100 mm or more and 500 mm or less. L4 is set, for example, to about 300 mm, and is desirably set to match the sum of L1 and L3. By matching L4 to the sum of L1 and L3, the position on axis X where the second lower support portion 32 supports the heat transfer tube T matches the position on axis X where the upper support mechanism 40 supports the heat transfer tube T. In this way, the heat transfer tube T can be reliably supported from above and below at the same position on axis X.

The cooling mechanism 50 is a mechanism for cooling the heat transfer tube T from the inside by causing cooling water (cooling medium) to flow into the heat transfer tube T from the upstream end Tu of the heat transfer tube T in the moving direction MD and causing the cooling water to flow out of the heat transfer tube T from the downstream end Td of the heat transfer tube T in the moving direction MD. As shown in FIG. 13, the cooling mechanism 50 includes an inlet pipe 51, an outlet pipe 52, a cooling unit 53, a flowmeter 54, an inlet coupling 55, and an outlet coupling 56. Here, the cooling medium may be liquid such as a heat medium or machine oil, or gas such as nitrogen, in addition to water.

The cooling mechanism 50 allows the cooling water, which is cooled by heat exchange with other cooling media in the cooling unit 53, to flow into the upstream end Tu of the heat transfer tube T via the inlet pipe 51. The inlet pipe 51 and the upstream end Tu of the heat transfer tube T are detachably connected by the inlet coupling 55. The cooling water that flows into the heat transfer tube T flows along the movement direction MD of the heat transfer tube T, passes through P0, which is the position to be welded by the overlay welding mechanism 20, and is guided to the downstream end Td of the heat transfer tube T.

The cooling water, whose temperature has risen near the welding position P0, is guided to the downstream end Td of the heat transfer tube T, flows out into the outlet piping 52, and is guided to the cooling unit 53. The outlet piping 52 and the downstream end Td of the heat transfer tube T are detachably connected by the outlet coupling 56. In this way, after being discharged from the cooling unit 53, the cooling water flows in the order of the inlet piping 51, the heat transfer tube T, and the outlet piping 52, and then returns to the cooling unit 53 to circulate.

The cooling mechanism 50 circulates cooling water from the upstream end Tu to the downstream end Td along the movement direction MD of the heat transfer tube T. The area from the upstream end Tu to P0 of the heat transfer tube T is an area where the weld bead WB is not formed. Therefore, the cooling water cooled by the cooling unit 53 is supplied to the vicinity of P0, which is the hottest part of the heat transfer tube T, without being heated and increasing in temperature, and the heat transfer tube T near P0 can be appropriately and efficiently cooled. This makes it possible to suppress changes in the amount of penetration due to thermal effects when the weld bead WB of the heat transfer tube T is formed, and warping deformation of the heat transfer tube T due to thermal stress.

The cooling mechanism 50 transmits the flow rate of the cooling water measured by the flow meter 54 to the control unit 90. The control unit 90 transmits a control signal to the cooling unit 53 to control the cooling unit 53 so that the flow rate measured by the flow meter 54 is maintained within a predetermined flow rate range. The cooling unit 53 controls the flow rate of the cooling water discharged to the inlet pipe 51 in response to the control signal transmitted from the control unit 90. In addition, a thermometer (not shown) may be provided near the cooling water flow meter 54 to control whether the temperature of the cooling water is within a predetermined range in addition to the flow rate.

When the flow rate of the cooling water measured by the flowmeter 54 falls below a predetermined lower limit, the control unit 90 determines that the cooling water is not properly cooling the heat transfer tube T, and controls the overlay welding mechanism 20 to temporarily suspend welding of the heat transfer tube T by the overlay welding mechanism 20.

The measurement mechanism 60 is a mechanism that is disposed at a measurement position Pm downstream in the movement direction MD of P0 where the overlay welding mechanism 20 is disposed. The measurement mechanism 60 is a mechanism that measures the outer diameter Do of the heat transfer tube T passing through the measurement position Pm, for example, by using a non-contact sensor. As shown in Figures 14 and 15, the measurement mechanism 60 includes, for example, an upper side light emitting unit 61, an upper side light receiving unit 62, a lower side light emitting unit 63, and a lower side light receiving unit 64.

For example, the upper light-emitting unit 61 has multiple light-emitting elements arranged in a vertical direction parallel to the axis Ym, and each light-emitting element irradiates light in a horizontal direction toward the upper light-receiving unit 62. The upper light-receiving unit 62 has multiple light-receiving elements arranged in a vertical direction parallel to the axis Ym, and each light-receiving element receives light irradiated from the multiple light-emitting elements of the upper light-emitting unit 61.

For example, the lower light-emitting unit 63 has multiple light-emitting elements arranged in a vertical direction parallel to the axis Ym, and each light-emitting element irradiates light in a horizontal direction toward the lower light-receiving unit 64. The lower light-receiving unit 64 has multiple light-receiving elements arranged in a vertical direction parallel to the axis Ym, and each light-receiving element receives light irradiated from the multiple light-emitting elements of the lower light-emitting unit 63.

The measuring mechanism 60 measures the outer diameter Do of the heat transfer tube T in a non-contact state based on the position of the lowest light receiving element where the upper light receiving unit 62 receives the irradiated light from the upper light emitting unit 61 and the position of the highest light receiving element where the lower light receiving unit 64 receives the irradiated light from the lower light emitting unit 63. The outer diameter Do of the heat transfer tube T measured by the measuring mechanism 60 is transmitted to the control unit 90. The control unit 90 may display the outer diameter Do of the heat transfer tube T measured by the measuring mechanism 60 on the display unit 85 so that, for example, an operator can visually check the build-up thickness of the weld bead WB of the heat transfer tube T.

Figure 14 is a diagram showing the state in which the measurement mechanism 60 measures a heat transfer tube T that is not overlaid. On the other hand, Figure 15 is a diagram showing the state in which the measurement mechanism 60 measures a heat transfer tube T that has a weld bead WB overlaid. As shown in Figure 14, the outer diameter Do2 of the heat transfer tube T that has been overlaid is larger than the outer diameter Do1 of the heat transfer tube T that has not been overlaid with the weld bead WB. The overlaid thickness of the weld bead WB is (Do2-Do1)/2.

The control unit 90 can determine whether the build-up thickness of the weld bead WB is appropriate based on the outer diameter Do1 of the heat transfer tube T that has not been overlaid and the outer diameter Do2 of the heat transfer tube T that has been overlaid, which are transmitted from the measurement mechanism 60. For example, when the control unit 90 determines that the build-up thickness of the weld bead WB is not appropriate because it is outside the target build-up thickness range, it causes the display unit 85 to display information indicating that the build-up thickness is not appropriate.

The control unit 90 may also control the overlay welding mechanism 20 to temporarily suspend the overlay welding of the heat transfer tube T by the overlay welding mechanism 20. At this time, the control unit 90 may display information on the difference between the various overlay welding conditions of the heat transfer tube T by the overlay welding mechanism 20 and the set values on the display unit 85, making it easier to determine the cause of the overlay thickness deviating from the appropriate thickness.

The main body 70 is a housing fixed to the installation surface S on which the welding device 200 is installed. The build-up welding mechanism 20, the first lower support part 31, and the upper support mechanism 40 are fixed to the main body 70. The main body 70 also includes a rack gear 71 and a rail 72 shown in FIG. 12, and the movable carriage 10 can move back and forth along the rail 72 in a moving direction MD parallel to the axis X direction.

As shown in FIG. 7, the imaging unit 80 is an imaging device that images the vicinity of the welding position including the tip of the tungsten electrode 21a provided at the tip of the welding torch 21 and the outer circumferential surface of the heat transfer tube T. The imaging unit 80 can output the image of the vicinity of the welding position to the display unit 85. The operator who operates the welding device 200 can visually check the image displayed on the display unit 85 to see whether there is any abnormality in the weld bead WB formed on the heat transfer tube T by the overlay welding mechanism 20. The image of the vicinity of the welding position may be adjusted in contrast or by adjusting the output intensity of each of the RGB colors to make it easier to monitor whether there is an abnormality in the formation of the weld bead WB. If the operator determines that there is an abnormality in the weld bead WB, he or she temporarily stops the operation of the welding device 200. In addition, the image captured by the imaging unit 80 is analyzed by the control unit 90 to determine whether there is an abnormality in the weld bead WB, and if it is determined that there is an abnormality, the operation of the welding device 200 may be automatically temporarily stopped by a signal from the control unit 90.

As shown in the control configuration diagram of FIG. 16, the control unit 90 is a device that controls each part of the welding device 200, including the moving mechanism 11, the rotating mechanism 12, and the overlay welding mechanism 20. The control unit 90 controls the overlay welding mechanism 20 to perform helical overlay welding on the outer peripheral surface of the heat transfer tube T while the moving mechanism 11 moves the heat transfer tube T in the moving direction MD along the axis X at a predetermined constant moving speed and the rotating mechanism 12 rotates the heat transfer tube T around the axis X at a predetermined constant rotation speed.

The control unit 90 is composed of, for example, a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and a computer-readable storage medium. A series of processes for realizing various functions is stored in the storage medium in the form of a program, for example, and the CPU reads this program into the RAM and executes information processing and calculation processing to realize various functions.

In this embodiment, the heat transfer tube T is formed of, for example, low alloy steel. The outer diameter Do of the unwelded heat transfer tube T is, for example, 30 mm or more and 50 mm or less. The length of the heat transfer tube T along the axis X is, for example, 2000 mm or more and 8000 mm or less. The welding device 200 performs welding using the overlay welding mechanism 20 so that the overlay thickness of the weld bead WB formed on the outer peripheral surface of the heat transfer tube T is, for example, 1 mm or more and 2.5 mm or less. The overlay thickness of the weld bead WB is set to be able to protect the heat transfer tube T from, for example, corrosion resistance and heat resistance.

The control unit 90 sets a predetermined moving speed of the heat transfer tube T in the axial direction by the moving mechanism 11 and a predetermined rotating speed of the heat transfer tube T around the axial direction by the rotating mechanism 12 so that the build-up thickness of the weld bead WB is 1 mm or more and 2.5 mm or less. The moving speed of the heat transfer tube T in the axial direction of the heat transfer tube T and the rotating speed of the heat transfer tube T around the axial direction of the heat transfer tube T may be controlled within a predetermined range so that the outer diameter Do2 of the heat transfer tube T with build-up welding and/or the build-up thickness of the weld bead WB based on the measurement value transmitted from the measuring mechanism 60 are within the range of the target specification. The control unit 90 controls the moving mechanism 11 so that the moving speed (feed rate) of the heat transfer tube T in the axial direction of the heat transfer tube T is, for example, 20 mm/min or more and 50 mm/min or less. The control unit 90 also controls the rotating mechanism 12 so that the rotating speed of the heat transfer tube T around the axial direction of the heat transfer tube T is, for example, 5 rpm or more and 10 rpm or less.

Other Embodiments
In the above description, the welding device 200 is provided with a single overlay welding mechanism 20 for performing helical overlay welding on a single heat transfer tube T, but other configurations are also possible. For example, the welding device 200 may be provided with a plurality of overlay welding mechanisms 20 for performing helical overlay welding on two or more heat transfer tubes T.

In this case, the welding device 200 includes a single main body 70 and a movable carriage 10, a build-up welding mechanism 20, a lower support mechanism 30, an upper support mechanism 40, a cooling mechanism 50, a measuring mechanism 60, an imaging unit 80, and a display unit 85, which are arranged horizontally adjacent to each other in a direction perpendicular to the axis X direction so that the axis X direction of the heat transfer tube T is approximately parallel to the axis X direction. In this case, multiple control units 90 may be provided, or all may be controlled by a single control unit 90.

In addition, the welding device 200 may be arranged so that the heat transfer tubes T are adjacent to each other with their longitudinal directions aligned, and the heat transfer tubes T are arranged symmetrically with respect to the worker, so that the worker can simultaneously check the welding state of the multiple overlay welding mechanisms 20 between adjacent heat transfer tubes T. For example, when four heat transfer tubes T are arranged with their longitudinal directions aligned, two heat transfer tubes T may be arranged symmetrically with respect to the worker in a direction perpendicular to the axis X direction of the heat transfer tubes T. In this way, the worker can simultaneously check the welding state of the multiple heat transfer tubes T arranged symmetrically, thereby reducing the number of workers.

In addition, when the welding device 200 is equipped with multiple overlay welding mechanisms 20 for spirally overlay welding two or more heat transfer tubes T, multiple display units 85 that display images captured by the imaging unit 80 of the welding state by each overlay welding mechanism 20 may be arranged so that one worker can see them simultaneously. In this way, the number of heat transfer tubes T that one worker can monitor increases, making it possible to improve productivity.

The second lower support part 32 and the upper support mechanism 40 shown in FIG. 9 may be modified as shown in FIG. 17. As shown in FIG. 17, the second lower support part 32 has a pair of spheres (first spheres) 32a that contact two circumferential points on the outer peripheral surface of the lower side of the heat transfer tube T, and a holding part (first holding part) 32b that holds each of the pair of spheres 32a rotatably in any direction.

The second lower support section 32 supports the lower part of the heat transfer tube T by sandwiching it at two different positions in the circumferential direction with a pair of spheres 32a, thereby being able to hold the center position (position of the axis X) of the heat transfer tube T at a fixed position. The upper support mechanism 40 also has spheres (second spheres) 40a that contact the outer peripheral surface of the upper side of the heat transfer tube T, and holding sections (second holding sections) 40b that hold each of the spheres 40a so that they can rotate in any direction.

The welding apparatus according to each of the above-described embodiments can be understood, for example, as follows.
A welding device (200) according to the present disclosure performs overlay welding on an outer peripheral surface of a cylindrical heat transfer tube (T) arranged along an axis (X), and includes a moving mechanism (11) for moving the heat transfer tube (T) along the axis (X), a rotating mechanism (12) for rotating the heat transfer tube (T) about the axis (X), and a welding device (200) for supplying a welding material to the outer peripheral surface of the heat transfer tube (T) which is fixed in position with respect to an installation surface (S) on which the welding device (200) is installed and which passes through a predetermined welding position (P0). and a control unit (90) that controls the moving mechanism (11), the rotation mechanism (12), and the overlay welding mechanism (20), wherein the control unit (90) controls the overlay welding mechanism (20) to perform helical overlay welding on the outer peripheral surface of the heat transfer tube (T) in a state in which the moving mechanism (11) moves the heat transfer tube (T) along the axis (X) and the rotation mechanism (12) rotates the heat transfer tube (T) around the axis (X).

According to the welding device of the present disclosure, the overlay welding mechanism is fixed to the installation surface on which the welding device is installed, so that a predetermined welding position is fixed to the installation surface. This suppresses fluctuations in the positional relationship between the welding torch of the overlay welding mechanism and the heat transfer tube T, such as the distance from the welding torch to the outer peripheral surface of the heat transfer tube and the angle with the welding torch, and suppresses fluctuations in the welding state at each position in the longitudinal direction of the heat transfer tube. This makes it possible to perform a spiral overlay welding on the outer peripheral surface of the heat transfer tube while appropriately satisfying welding specifications such as overlay thickness and overlay surface roughness.

The welding apparatus of the present disclosure includes a lower support mechanism that supports the heat transfer tube from the vertically lower side, and the lower support mechanism has a pair of first spheres that contact two circumferential points on the outer surface of the heat transfer tube, and a first holding portion that holds the first spheres rotatably in any direction.
According to the welding device of the present disclosure, the pair of first spheres of the lower support mechanism can stably support the lower side of the heat transfer tube at two circumferential points on the outer peripheral surface. In addition, since the pair of first spheres can rotate in any direction, the lower side of the heat transfer tube can be smoothly supported without applying excessive friction to the heat transfer tube, which moves along its axis and rotates around its axis at the same time.

In the welding apparatus of the present disclosure, the lower support mechanism is equipped with a first switching mechanism that can switch between a support state in which the first sphere is held in a position that supports the heat transfer tube, and a retracted state in which the first sphere is retracted to a position that does not support the heat transfer tube.
According to the welding apparatus of the present disclosure, the lower support mechanism is switchable between a supported state and a retracted state, so that, for example, when other mechanisms are connected to the end of the heat transfer tube, the lower support mechanism can be retracted from the heat transfer tube when necessary to avoid interference between the lower support mechanism and other mechanisms, such as a moving mechanism.

The welding apparatus of the present disclosure includes an upper support mechanism that supports the heat transfer tube from above, and the upper support mechanism includes a second sphere that contacts the outer peripheral surface of the heat transfer tube, a second holding portion that holds the second sphere rotatably in any direction, and a second switching mechanism that can switch between a support state in which the second sphere is held in a position that supports the heat transfer tube and a retracted state in which the second sphere is retracted to a position that does not support the heat transfer tube.
According to the welding device of the present disclosure, the heat transfer tube, which is supported at two points on the lower side by the lower support mechanism, can be supported from above by the upper support mechanism to reliably fix the position of the heat transfer tube. In addition, since the second sphere can rotate in any direction, the heat transfer tube can be smoothly supported from above without applying excessive frictional force to the heat transfer tube, which moves along its axis and rotates around its axis at the same time.

Furthermore, since the upper support mechanism can be switched between a supported state and a retracted state, for example, when another mechanism is connected to the end of the heat transfer tube, the upper support mechanism can be retracted from the heat transfer tube to avoid interference between the upper support mechanism and the other mechanism.

In the welding apparatus of the present disclosure, a first distance along the axis from the welding position to the lower support mechanism located upstream in the movement direction of the heat transfer tube is shorter than a second distance along the axis from the welding position to the lower support mechanism located downstream in the movement direction.
The lower support mechanism arranged on the upstream side in the moving direction of the heat transfer tube is arranged at a position closer to the welding position than the lower support mechanism arranged on the downstream side.

Therefore, the outer peripheral surface of the heat transfer tube where no welding has been performed is supported near the welding position, and fluctuations in the positional relationship between the welding torch of the overlay welding mechanism and the heat transfer tube T, such as the distance from the welding torch to the outer peripheral surface of the heat transfer tube and the angle with the welding torch, can be suppressed. In addition, the lower support mechanism located downstream in the movement direction of the heat transfer tube is located at a position farther away from the welding position than the lower support mechanism located upstream. Therefore, the outer peripheral surface of the heat transfer tube where welding has been performed and the surface has an uneven shape is supported at a position away from the welding position, and vibrations caused when the uneven shape passes through the lower support mechanism can be suppressed from being transmitted to the overlay welding mechanism, and the effects of minute positional fluctuations in the axial position of the heat transfer tube due to the distribution of the thickness of the weld bead can be suppressed.

The welding apparatus according to the present disclosure is provided with a cooling mechanism that cools the heat transfer tube by flowing a cooling medium into the heat transfer tube from one end upstream in the direction of movement of the heat transfer tube and flowing the cooling medium out into the heat transfer tube from the other end downstream in the direction of movement of the heat transfer tube.
According to the welding apparatus of the present disclosure, the heat transfer tube heated by the overlay welding mechanism near the welding position can be appropriately and effectively cooled by a cooling medium, and changes in the amount of penetration due to thermal effects after welding and warping deformation of the heat transfer tube due to thermal stress can be appropriately suppressed.

The welding apparatus according to the present disclosure includes a plurality of moving mechanisms that move a plurality of the heat transfer tubes, a plurality of rotating mechanisms that rotate the plurality of the heat transfer tubes, and a plurality of the overlay welding mechanisms that perform welding on the outer peripheral surfaces of the plurality of the heat transfer tubes, and the plurality of the heat transfer tubes are arranged adjacent to each other in a horizontal direction perpendicular to the axial direction.
According to the welding apparatus of the present disclosure, multiple heat transfer pipes are arranged adjacent to each other, allowing one worker to simultaneously monitor the welding status of multiple overlay welding mechanisms, thereby reducing the number of workers required for monitoring.

The welding apparatus according to the present disclosure includes a measurement mechanism that is arranged at a measurement position downstream of the welding position in the direction of movement of the heat transfer tube, and that measures the outer diameter of the heat transfer tube passing through the measurement position and/or calculates the thickness of the overlay weld.
According to the welding apparatus of the present disclosure, by measuring the outer diameter of a heat transfer tube on which spiral overlay welding has been performed and/or calculating the thickness of the overlay welding, it is possible to appropriately determine whether the heat transfer tube properly meets welding specifications such as the overlay thickness and overlay surface roughness, and to control a moving mechanism that moves the heat transfer tube and a rotating mechanism that rotates the heat transfer tube so that the welding specifications are appropriate.

The control method of the welding device (200) described in the embodiment described above can be understood, for example, as follows.
A control method for a welding apparatus (200) according to the present disclosure is a control method for a welding apparatus that performs overlay welding on an outer peripheral surface of a cylindrical heat transfer tube arranged along an axis, the welding apparatus comprising: a moving mechanism that moves the heat transfer tube along the axis; a rotating mechanism that rotates the heat transfer tube about the axis; and an overlay welding mechanism that is fixed to an installation surface on which the welding apparatus is installed and that performs welding while supplying a welding material to the outer peripheral surface of the heat transfer tube that passes through a predetermined welding position, and the control method comprises a control step of controlling the welding apparatus such that, with the moving mechanism moving the heat transfer tube along the axis and the rotating mechanism rotating the heat transfer tube about the axis, the overlay welding mechanism performs helical overlay welding on the outer peripheral surface of the heat transfer tube.

According to the control method for the welding device (200) of the present disclosure, the overlay welding mechanism is fixed to the installation surface on which the welding device is installed, and therefore a predetermined welding position is fixed to the installation surface. Therefore, fluctuations in the positional relationship between the welding torch and the heat transfer tube, such as the distance from the welding torch of the overlay welding mechanism to the outer peripheral surface of the heat transfer tube and the angle with the welding torch, are suppressed, and fluctuations in the welding state at each position in the longitudinal direction of the heat transfer tube are suppressed. This makes it possible to perform a spiral overlay welding on the outer peripheral surface of the heat transfer tube while appropriately satisfying welding specifications such as overlay thickness and overlay surface roughness.

In the control method for a welding apparatus according to the present disclosure, the welding apparatus includes a measurement mechanism (60) that is arranged at a measurement position downstream of the welding position in the movement direction of the heat transfer tube and that measures the outer diameter of the heat transfer tube passing through the measurement position and/or calculates the thickness of the overlay weld, and the control process controls the moving speed at which the moving mechanism moves the heat transfer tube along the axis and the rotation speed at which the rotation mechanism rotates the heat transfer tube about the axis, so that the outer diameter of the heat transfer tube measured by the measurement mechanism and/or the thickness of the overlay weld measured by the measurement mechanism are within a predetermined range.
According to the control method for a welding apparatus according to the present disclosure, the moving speed and the rotation speed of the heat transfer tube are appropriately controlled in accordance with the measurement results from the measurement mechanism so that the thickness of the overlay weld falls within a predetermined range.

10 Movable carriage 11 Moving mechanism 12 Rotating mechanism 20 Overlay welding mechanism 21 Welding torch 21a Tungsten electrode 30 Lower support mechanism 31 First lower support part 31a Sphere (first sphere)
32 Second lower support portion 32a sphere (first sphere)
33 Third lower support portion 33a sphere (first sphere)
33c Height adjustment mechanism (switching mechanism)
40 Upper support mechanism 40a sphere (second sphere)
40c Height adjustment mechanism 50 Cooling mechanism 60 Measuring mechanism 70 Main body 80 Imaging unit 85 Display unit 90 Control unit 200 Welding device MD Movement direction S Installation surface T Heat transfer tube Td Downstream end Tu Upstream end WB Weld bead

Claims (7)

A welding device that performs overlay welding on an outer peripheral surface of a cylindrical heat transfer tube arranged along an axis line,
a moving mechanism that moves the heat transfer tube along the axis;
A rotation mechanism that rotates the heat transfer tube about the axis;
a build-up welding mechanism that is fixed in position relative to an installation surface on which the welding device is installed and that supplies a welding material to an outer peripheral surface of the heat transfer tube passing a predetermined welding position while welding;
a lower support mechanism that supports the heat transfer tube from a vertically lower side;
A control unit that controls the moving mechanism, the rotating mechanism, and the overlay welding mechanism,
The control unit controls the overlay welding mechanism to perform helical overlay welding on an outer peripheral surface of the heat transfer tube in a state in which the moving mechanism moves the heat transfer tube along the axis and the rotating mechanism rotates the heat transfer tube about the axis,
The lower support mechanism includes:
A pair of first spheres in contact with two circumferential points on an outer peripheral surface of the heat transfer tube;
A first holding portion that holds the first sphere so that the first sphere can rotate in any direction;
A welding apparatus comprising a first switching mechanism capable of switching between a support state in which the first sphere is held in a position supporting the heat transfer tube , and a retracted state in which the first sphere is retracted to a position not supporting the heat transfer tube. A welding device that performs overlay welding on an outer peripheral surface of a cylindrical heat transfer tube arranged along an axis line,
a moving mechanism that moves the heat transfer tube along the axis;
A rotation mechanism that rotates the heat transfer tube about the axis;
a build-up welding mechanism that is fixed in position relative to an installation surface on which the welding device is installed and that supplies a welding material to an outer peripheral surface of the heat transfer tube passing a predetermined welding position while welding;
a lower support mechanism that supports the heat transfer tube from a vertically lower side;
An upper support mechanism that supports the heat transfer tube from above in the vertical direction,
A control unit that controls the moving mechanism, the rotating mechanism, and the overlay welding mechanism,
The control unit controls the overlay welding mechanism to perform helical overlay welding on an outer peripheral surface of the heat transfer tube in a state in which the moving mechanism moves the heat transfer tube along the axis and the rotating mechanism rotates the heat transfer tube about the axis,
The lower support mechanism includes:
A pair of first spheres in contact with two circumferential points on an outer peripheral surface of the heat transfer tube;
A first holding portion that holds the first sphere so that the first sphere can be rotated in any direction,
The upper support mechanism includes:
A second sphere that contacts two points in the circumferential direction of the outer peripheral surface of the heat transfer tube;
A second holding portion that holds the second sphere rotatably in any direction;
A welding device having a second switching mechanism that can switch between a support state in which the second sphere is held in a position that supports the heat transfer tube, and a retracted state in which the second sphere is retracted to a position that does not support the heat transfer tube. A welding device that performs overlay welding on an outer peripheral surface of a cylindrical heat transfer tube arranged along an axis line,
a moving mechanism that moves the heat transfer tube along the axis;
A rotation mechanism that rotates the heat transfer tube about the axis;
a build-up welding mechanism that is fixed in position relative to an installation surface on which the welding device is installed and that supplies a welding material to an outer peripheral surface of the heat transfer tube passing a predetermined welding position while welding;
a lower support mechanism that supports the heat transfer tube from a vertically lower side;
A control unit that controls the moving mechanism, the rotating mechanism, and the overlay welding mechanism,
The control unit controls the overlay welding mechanism to perform helical overlay welding on an outer peripheral surface of the heat transfer tube in a state in which the moving mechanism moves the heat transfer tube along the axis and the rotating mechanism rotates the heat transfer tube about the axis,
The lower support mechanism includes:
A pair of first spheres in contact with two circumferential points on an outer peripheral surface of the heat transfer tube;
A first holding portion that holds the first sphere so that the first sphere can be rotated in any direction,
A welding device in which a first distance along the axis from the welding position to the lower support mechanism located upstream in the movement direction of the heat transfer tube is shorter than a second distance along the axis from the welding position to the lower support mechanism located downstream in the movement direction. 4. The welding device according to claim 1, further comprising a cooling mechanism that cools the heat transfer tube by causing a cooling medium to flow into the heat transfer tube from one end that is upstream in the movement direction of the heat transfer tube and causing the cooling medium to flow out of the heat transfer tube from the other end that is downstream in the movement direction of the heat transfer tube. A plurality of the movement mechanisms that move the plurality of the heat transfer tubes;
A plurality of the rotation mechanisms that rotate the plurality of the heat transfer tubes;
A plurality of the overlay welding mechanisms for welding the outer peripheral surfaces of the heat transfer tubes,
5. The welding device according to claim 1, wherein the heat transfer tubes are arranged adjacent to each other in a horizontal direction perpendicular to the axial direction. A welding device that performs overlay welding on an outer peripheral surface of a cylindrical heat transfer tube arranged along an axis line,
a moving mechanism that moves the heat transfer tube along the axis;
A rotation mechanism that rotates the heat transfer tube about the axis;
a build-up welding mechanism that is fixed in position relative to an installation surface on which the welding device is installed and that supplies a welding material to an outer peripheral surface of the heat transfer tube passing a predetermined welding position while welding;
A measurement mechanism that is disposed at a measurement position downstream of the welding position in the moving direction of the heat transfer tube and measures an outer diameter of the heat transfer tube passing through the measurement position and/or calculates a thickness of the overlay welding ;
A control unit that controls the moving mechanism, the rotating mechanism, and the overlay welding mechanism ,
The control unit controls the overlay welding mechanism to perform spiral overlay welding on the outer peripheral surface of the heat transfer tube while the moving mechanism moves the heat transfer tube along the axis and the rotating mechanism rotates the heat transfer tube around the axis. A method for controlling a welding apparatus for overlay welding an outer peripheral surface of a cylindrical heat transfer tube arranged along an axis line, comprising:
The welding device includes:
a moving mechanism that moves the heat transfer tube along the axis;
A rotation mechanism that rotates the heat transfer tube about the axis;
a build-up welding mechanism that is fixed in position relative to an installation surface on which the welding device is installed and that supplies a welding material to an outer peripheral surface of the heat transfer tube passing a predetermined welding position while welding;
A measurement mechanism is provided at a measurement position downstream of the welding position in the moving direction of the heat transfer tube, and measures an outer diameter of the heat transfer tube passing through the measurement position and/or calculates a thickness of the overlay welding;
A control process of controlling the welding device so that the overlay welding mechanism performs helical overlay welding on an outer peripheral surface of the heat transfer tube in a state in which the moving mechanism moves the heat transfer tube along the axis and the rotating mechanism rotates the heat transfer tube around the axis,
The control process is a control method for a welding apparatus, which controls a moving speed at which the moving mechanism moves the heat transfer tube along the axis and a rotation speed at which the rotation mechanism rotates the heat transfer tube around the axis, so that the outer diameter of the heat transfer tube measured by the measuring mechanism and/or the thickness of the weld overlay measured by the measuring mechanism are within a predetermined range.

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