JP2020185604A - Double pipe welding method and double pipe welding device - Google Patents

Abstract

To make it possible to easily perform a double pipe welding work.SOLUTION: According to this double pipe welding method, a structure, which has an outer cylinder and an inner cylinder with a prescribed central axis as a center and in which the outer cylinder and the inner cylinder are integrally fixed at one end in an axial direction of the central axis, is provided, the other ends in each axial direction of two double pipe structures, of which the other end in the axial direction is opened, are welded, thereby forming a double pipe. The double pipe welding method includes: a step at which the other end of a first structure and the other end of a second structure of two double pipe structures are so made as to be opposite to each other so that at least the inner cylinders contact or are proximate to each other; a step at which electron beam is so radiated as to penetrate or pass between the outer cylinders from the lateral side of the outer cylinder and arrive at the opposite parts of the inner cylinders with respect to the first structure and the second structure which are so located as to be opposite to each other, thereby welding the inner cylinders; and a step at which electron beam is radiated to the opposite parts of the outer cylinders with respect to the first structure and the second structure, which are so located as to be opposite to each other, from the lateral side of the outer cylinder, thereby welding the outer cylinders.SELECTED DRAWING: Figure 4

Description

The present invention relates to a method for welding a double pipe and a device for welding a double pipe.

A superconducting accelerator that accelerates charged particles such as electrons and protons by a superconducting accelerating cavity is known (see, for example, Patent Document 1). Such a superconducting accelerator becomes superconducting by cooling a superconducting accelerating cavity formed of a superconducting material with a refrigerant. As a result, the electrical resistance of the superconducting acceleration cavity becomes almost zero, and the charged particles can be efficiently accelerated without power loss. The superconducting accelerating cavity used in this superconducting accelerator is manufactured by sheet metal processing of a superconducting material such as niobium and welding with an electron beam.

Japanese Patent No. 3746611

When welding double-tube structures such as a superconducting accelerator, for example, if a structure or the like is provided at an end different from the end to be joined, it is necessary to irradiate an electron beam from a direction avoiding the structure. This increases the difficulty of welding work. Therefore, it is required to easily perform the welding work.

The present invention has been made in view of the above, and an object of the present invention is to provide a double pipe welding method and a double pipe welding device capable of easily performing a welding operation.

The method for welding a double pipe according to the present disclosure has an outer cylinder and an inner cylinder centered on a predetermined central axis, and the outer cylinder and the inner cylinder are integrated at one end in the axial direction of the central axis. A structure to be fixed with is provided, and the other end in the axial direction of each of the two double pipe structures in which the other end in the axial direction is open is welded to each other to form a double pipe. A method of welding a double pipe, wherein the other end of the first structure and the other of the second structure of the two double pipe structures are in contact with each other or close to each other. The inner cylinder penetrates or passes between the outer cylinders from the side of the outer cylinder with respect to the first structure and the second structure arranged to face each other. Welding the inner cylinders by irradiating electron beams so as to reach the opposing portions, and from the side of the outer cylinder with respect to the first structure and the second structure arranged to face each other. This includes irradiating the facing portions of the outer cylinders with the electron beam to weld the outer cylinders to each other.

The double pipe welding apparatus according to the present disclosure has an outer cylinder and an inner cylinder centered on a predetermined central axis, and the outer cylinder and the inner cylinder are integrated at one end in the axial direction of the central axis. Welding of double pipes to form a double pipe by welding the other ends of each of the two double pipe structures fixed with and open at the other end in the axial direction. In the device, the other end of the first structure and the other end of the second structure of the two double pipe structures are arranged so that at least the inner cylinders are in contact with each other or close to each other. A structure holding portion to be opposed to each other, an electron beam irradiating portion for irradiating an electron beam to the first structure and the second structure arranged to face each other from the side of the outer cylinder, the structure holding portion, and the structure holding portion. By controlling the electron beam irradiation unit, the first structure and the second structure arranged to face each other are penetrated or passed between the outer cylinders from the side of the outer cylinders and inside the inner cylinder. The inner cylinders are welded to each other by irradiating an electron beam so as to reach the facing portions of the cylinders, and the first structure and the second structure arranged to face each other are described from the side of the outer cylinder. A control unit for irradiating the facing portions of the outer cylinders with the electron beam to weld the outer cylinders to each other is provided.

According to the present disclosure, it is possible to provide a double pipe welding method and a double pipe welding device capable of easily performing a welding operation.

FIG. 1 is a diagram schematically showing an example of a welding apparatus according to the present embodiment. FIG. 2 is a cross-sectional view showing an example of the superconducting accelerator manufactured in the present embodiment. FIG. 3 is a plan view showing an example of the superconducting accelerator manufactured in the present embodiment. FIG. 4 is a flowchart showing an example of a welding method for a double pipe according to the present embodiment. FIG. 5 is a diagram showing an example of a welding process. FIG. 6 is a diagram showing an example of a welding process. FIG. 7 is a diagram showing another example of the welding process. FIG. 8 is a diagram showing another example of the welding process. FIG. 9 is a diagram showing another example of the welding process. FIG. 10 is a diagram showing another example of the welding process. FIG. 11 is a diagram showing another example of the welding process. FIG. 12 is a diagram showing another example of the welding process. FIG. 13 is a diagram showing another example of the welding process. FIG. 14 is a diagram showing a partial configuration of a superconducting accelerator formed by welding. FIG. 15 is a diagram showing another example of the welding process.

Hereinafter, an embodiment of a double pipe welding method and a double pipe welding apparatus according to the present invention will be described with reference to the drawings. The present invention is not limited to this embodiment. In addition, the components in the following embodiments include those that can be easily replaced by those skilled in the art, or those that are substantially the same.

FIG. 1 is a diagram schematically showing an example of a welding apparatus 100 according to the present embodiment. As shown in FIG. 1, the welding apparatus 100 includes a chamber 10, an electron beam irradiation unit 20, and a control unit 30. In the present embodiment, the welding device 100 is an electron beam irradiating device that irradiates an object with an electron beam.

The chamber 10 houses a double-tube structure to be irradiated with an electron beam. The chamber 10 has a stage 11 and a structure holding portion 12. The stage 11 supports the structure holding portion 12. The stage 11 can rotate around a predetermined rotation axis while supporting the structure holding portion 12.

The structure holding unit 12 holds the irradiation target of the electron beam. As the structure holding portion 12, only the structure that holds the end portion of, for example, the stage 11 side (lower side in the vertical direction) of the objects (the first structure 51 and the second structure 52, which will be described later) is shown. However, the present invention is not limited to this, and a structure for holding the end portion on the side opposite to the stage 11 (upper side in the vertical direction) may be provided. The structure holding portion 12 can rotate integrally with the stage 11 by rotating the stage 11.

The electron beam irradiation unit 20 includes an irradiation unit 21 and an imaging unit 22. The irradiation unit 21 is provided with a configuration for irradiating an electron beam, such as a cathode electrode (not shown), a grid electrode, an anode electrode, and an electromagnetic coil. The irradiation unit 21 can adjust the diameter of the electron beam. The imaging unit 22 captures an image of the irradiation position of the electron beam. The captured image can be displayed by a display unit (not shown). The operator who operates the welding apparatus 100 can easily visually recognize the state of the portion irradiated with the electron beam by looking at the captured image. Further, when the operator operates while viewing the captured image, the operator can irradiate the electron beam with high accuracy.

The control unit 30 controls the operations of the chamber 10 and the electron beam irradiation unit 20. The control unit 30 controls each operation of, for example, the stage 11 and the structure holding unit 12 in the chamber 10. The control unit 30 controls the operations of the irradiation unit 21 and the imaging unit 22 of the electron beam irradiation unit 20, for example.

2 and 3 are views showing an example of the superconducting accelerator 40 manufactured in the present embodiment. FIG. 2 shows a cross-sectional view in a plane passing through the central axis, and FIG. 3 shows a top view. The superconducting accelerator 40 shown in FIGS. 2 and 3 is, for example, a coaxial 1/2 wavelength type superconducting accelerator (HWR: Half Wave Resonator). The superconducting accelerator 40 has an acceleration cavity 41, a stem 42, a beam tube 43, and cleaning ports 44 and 45.

The acceleration cavity 41 accelerates a charged particle beam B composed of charged particles such as electrons and protons. The acceleration cavity 41 is formed of, for example, a cylindrical shape by a superconducting material such as niobium, and has a hollow chamber shape continuous in the axial direction of the central axis. The acceleration cavity 41 is joined to the cleaning port 44 via a welded portion 46. Further, the acceleration cavity 41 is joined to the cleaning port 45 via the welded portion 48.

The acceleration cavity 41 has a connection port connected to a vacuum pump (not shown). The inside of the acceleration cavity 41 can be evacuated by evacuating with a vacuum pump. Further, the acceleration cavity 41 is provided with a power input unit (not shown). The acceleration cavity 41 generates an electric field for accelerating the charged particle beam B by inputting high-frequency power from the power input unit.

The stem 42 is arranged inside the acceleration cavity 41 and is formed of a superconducting material such as niobium into a cylindrical shape coaxial with the acceleration cavity 41, for example. The stem 42 has a hollow chamber shape that is continuous in the axial direction of the central axis. That is, the superconducting accelerator 40 has a double tube structure with an acceleration cavity 41 and a stem 42. The stem 42 is joined to the cleaning port 44 via a welded portion 47. Further, the stem 42 is joined to the cleaning port 45 via the welded portion 49.

The beam tube 43 extends in a direction orthogonal to the central axis of the acceleration cavity 41 and the stem 42. The beam tube 43 is provided so as to penetrate the acceleration cavity 41 and the stem 42. The beam tube 43 allows the charged particle beam B to pass through.

The cleaning ports 44 and 45 are introduction ports for introducing cleaning water for cleaning the inside of the acceleration cavity 41. The cleaning ports 44 and 45 are arranged at both ends in the axial direction of the central axis in the superconducting accelerator 40.

The superconducting accelerator 40 configured in this way is put into a superconducting state by cooling the acceleration cavity 41. The charged particle beam B enters the acceleration cavity 41 from the beam tube 43, and is sent out of the acceleration cavity 41 via the stem 42. A plurality of superconducting accelerators 40 are connected along the particle flow path of the charged particle beam B. In the adjacent superconducting accelerators 40, the beam tube 43 of one superconducting accelerator 40 and the beam tube 43 of the other superconducting accelerator 40 are connected via a connecting tube (not shown).

The superconducting accelerator 40 configured as described above is manufactured by sheet metal processing and welding of a superconducting material such as niobium. For example, the acceleration cavity 41, the stem 42 and the beam tube 43 are assembled. Further, a cleaning port 44 and a cleaning port 45 are formed, respectively. Then, the cleaning port 44 is first welded to the assembled structure of the acceleration cavity 41, the stem 42, and the beam tube 43 by using an electron beam. As a result, the first structure 51 shown in FIG. 2 is formed. The first structure 51 is a double-tube structure having a double-tubular acceleration cavity 41 and a stem 42. Hereinafter, the acceleration cavity 41 of the first structure 51 will be referred to as an outer cylinder 51a, and the stem 42 will be referred to as an inner cylinder 51b. In the first structure 51, the outer cylinder 51a and the inner cylinder 51b are integrally fixed by the cleaning port 44 at one end, and the outer cylinder 51a and the inner cylinder 51b are opened at the other end to expose the cross section. It is in a state of being.

Next, the cleaning port 45 is welded to the first structure 51 using an electron beam. The cleaning port 45 has a configuration in which a portion to be joined to the acceleration cavity 41 and a portion to be joined to the stem 42 are connected to the opening portion into which the washing water is introduced. The cleaning port 45 is a double-tube structure in which a portion to be joined to the acceleration cavity 41 and a portion to be joined to the stem 42 are formed in a double tubular shape. Hereinafter, the cleaning port 45 will be referred to as a second structure 52, the portion to be joined to the acceleration cavity 41 will be referred to as an outer cylinder 52a, and the portion to be joined to the stem 42 will be referred to as an inner cylinder 52b. In the second structure 52, the outer cylinder 52a and the inner cylinder 52b are integrally fixed at one end (the end on the opening side), and the outer cylinder 52a and the inner cylinder 52b are opened at the other end. The cross section is exposed.

FIG. 4 is a flowchart showing an example of a welding method for a double pipe according to the present embodiment. As shown in FIG. 4, the method of welding the double pipe includes a step of arranging the other end of the first structure 51 and the other end of the second structure 52 so as to face each other (step S10). It penetrates or passes between the outer cylinders 51a and 52a from the side of the outer cylinders 51a and 52a with respect to the first structure 51 and the second structure 52, and reaches the facing portion 5454 of the inner cylinders 51b and 52b. The step of irradiating the electron beam to weld the inner cylinders 51b and 52b (step S20) and the side of the outer cylinders 51a and 52a with respect to the first structure 51 and the second structure 52 arranged to face each other. The step (step S30) of irradiating the facing portions 53 of the outer cylinders 51a and 52a with an electron beam to weld the outer cylinders 51a and 52a is included. The method of welding a double pipe according to the present embodiment is performed using, for example, a welding device 100. In this case, each step S10, S20, S30 is performed by the control unit 30 controlling the operation of each part of the welding device 100. The operator may manually perform each operation.

In step S10, the first structure 51 and the second structure 51 and the second structure 51 face each other so that the end portion of the outer cylinder 51a and the end portion of the outer cylinder 52a face each other and the end portion of the inner cylinder 51b and the end portion of the inner cylinder 52b face each other. The structure 52 and the structure 52 are held by the structure holding portion 12.

In steps S20 and S30 (hereinafter, may be referred to as a welding process), the outer cylinders 51a and 52a are welded to each other and the inner cylinders 51b and 52b are welded to each other by the following methods.

5 and 6 are views showing an example of a welding process. As shown in FIGS. 5 and 6, when the inner cylinders 51b and 52b are welded to each other, the electron beam EB is irradiated from the irradiation unit 21 to the facing portions 53 of the outer cylinders 51a and 52a. At this time, the irradiation unit 21 irradiates the electron beam EB so that a part of the electron beam EB penetrates the facing portions 53 of the outer cylinders 51a and 52a and reaches the facing portions 54 of the inner cylinders 51b and 52b.

As a result, first, the outer cylinders 51a and 52a are welded to each other by the electron beam EB that irradiates the facing portions 53 of the outer cylinders 51a and 52a. Further, the electron beam EBa penetrating between the outer cylinders 51a and 52a irradiates the facing portions 54 of the inner cylinders 51b and 52b. The inner cylinders 51b and 52b are welded by the electron beam EBa. That is, by irradiating the electron beam EB once, the outer cylinders 51a and 52a and the inner cylinders 51b and 52b are welded to each other at the same time.

The intensity of the electron beam EB that penetrates the facing portions 53 of the outer cylinders 51a and 52a is lower than that of the electron beam EB that irradiates the facing portions 53 of the outer cylinders 51a and 52a. Therefore, the irradiation unit 21 adjusts the irradiation intensity of the electron beam EB so that the intensity of the penetrating electron beam EBa can be welded to the inner cylinders 51b and 52b.

As shown in FIG. 6, the outer cylinders 51a and 52a and the inner cylinders 51b and 52b are welded to each other at the same time by rotating the first structure 51 and the second structure 52 once around the central axis AX. Can be done.

7 to 9 are views showing another example of the welding process. As shown in FIG. 7, when the outer cylinder 51a and the outer cylinder 52a face each other and the inner cylinder 51b and the inner cylinder 52b face each other, the distance d1 of the facing portions 53 of the outer cylinders 51a and 52a is the inner cylinder 51b, The first structure 51 and the second structure 52 are formed so as to be larger than the distance between the facing portions 54 of 52b.

In this state, when the inner cylinders 51b and 52b are welded to each other, as shown in FIG. 8, the electron beam EB is passed between the outer cylinders 51a and 52a to reach the facing portion 54 of the inner cylinders 51b and 52b. The inner cylinders 51b and 52b are welded to each other by the electron beam EB that irradiates the facing portions 54 of the inner cylinders 51b and 52b. When the inner cylinders 51b and 52b are welded to each other, so-called welding shrinkage occurs in which the first structure 51 and the second structure 52 shrink in a direction approaching each other. Due to this welding shrinkage, the distance between the facing portions 53 of the outer cylinders 51a and 52a is shortened from the distance d1 to the distance d2 (d1> d2). After that, as shown in FIG. 9, the electron beam EB is irradiated from the irradiation unit 21 to the facing portions 53 of the outer cylinders 51a and 52a. As a result, the outer cylinders 51a and 52a are welded to each other. By adjusting the distance d1 so that the distance d2 after being shortened by welding shrinkage is smaller than the diameter of the electron beam EB, the outer cylinders 51a, 52a and the inner cylinder 51b are not changed in diameter of the electron beam. , 52b can be welded.

10 and 11 are diagrams showing other examples of the welding process. In the examples shown in FIGS. 10 and 11, similarly to the example shown in FIG. 7, when the outer cylinder 51a and the outer cylinder 52a face each other and the inner cylinder 51b and the inner cylinder 52b face each other, the outer cylinder The first structure 51 and the second structure 52 are formed so that the distance between the facing portions 53 of the 51a and 52a is larger than the distance between the facing portions 54 of the inner cylinders 51b and 52b.

In this state, when the inner cylinders 51b and 52b are welded to each other, as shown in FIG. 10, the diameter of the electron beam EB is reduced by the slit SL, and the electron beam EBb is emitted from the slit SL. The size of the opening of the slit SL is set so that the electron beam EBb passes between the outer cylinders 51a and 52a. The electron beam EBb that has passed through the slit SL passes between the outer cylinders 51a and 52a and reaches the opposite portion 54 of the inner cylinders 51b and 52b. When the electron beam EBb irradiates the facing portions 54 of the inner cylinders 51b and 52b, the inner cylinders 51b and 52b are welded to each other.

After that, as shown in FIG. 11, the slit SL is removed from between the irradiation unit 21 and the outer cylinders 51a and 52a, and the electron beam EB is irradiated from the irradiation unit 21 to the facing portions 53 of the outer cylinders 51a and 52a. As a result, the outer cylinders 51a and 52a are welded to each other.

12 and 13 are diagrams showing other examples of the welding process. As shown in FIG. 12, when the outer cylinder 51a and the outer cylinder 52a face each other and the inner cylinder 51b and the inner cylinder 52b face each other, the positions of the facing portions 53 of the outer cylinders 51a and 52a and the inner cylinders 51b and 52b The positions of the facing portions 54 are displaced in the axial direction of the central axis AX, and the ends 51c and 52c of the outer cylinders 51a and 52a on the facing portion 53 side are directed toward the facing portions 54 of the inner cylinders 51b and 52b. The first structure 51 and the second structure 52 are formed so as to be tilted.

In this state, when welding the inner cylinders 51b and 52b to each other, as shown in FIG. 13, the electron beam EB passes between the outer cylinders 51a and 52a along the inclination direction of the facing portions 53 of the outer cylinders 51a and 52a. The electron beam EB is irradiated so as to be performed. As a result, the electron beam EB passes between the outer cylinders 51a and 52a and reaches the facing portion 54 of the inner cylinders 51b and 52b. The electron beam EB irradiates the facing portions 54 of the inner cylinders 51b and 52b. As a result, the inner cylinders 51b and 52b are welded to each other. After that, as shown in FIG. 13, the ends 51c and 52c of the outer cylinders 51a and 52a are irradiated with the electron beam EB. As a result, the outer cylinders 51a and 52a are welded to each other.

FIG. 14 is a diagram showing a partial configuration of the superconducting accelerator 40 formed by welding. As shown in FIG. 14, on the inner surface 41a of the acceleration cavity 41, a protruding portion 41b protruding inward is formed by the welded portion 48. Further, on the outer surface 42a of the stem 42, a protruding portion 42b that protrudes outward is formed by the welded portion 49.

For example, when the welded portion 49 is arranged at the same position with respect to the welded portion 48 in the axial direction of the central axis AX (virtual welded portion 49a shown by a broken line in the figure), the welded portion 48 and the virtual welded portion 49a The electric field tends to concentrate between them. Therefore, an unexpected discharge or the like is likely to occur. On the other hand, in the example shown in FIG. 14, the welded portion 48 and the welded portion 49 are displaced in the axial direction of the central axis AX, that is, the protruding portion 41b and the protruding portion 42b are displaced in the axial direction of the central axis AX. .. In this case, the distance d4 between the protrusion 41b and the protrusion 42b is larger than the distance d3 between the protrusion 41b and the protrusion 49b when the virtual welded portion 49a is provided, so that the concentration of the electric field is concentrated. It is suppressed.

FIG. 15 is a diagram showing another example of the welding process. For example, when the inner cylinders 51b and 52b are welded and then the outer cylinders 51a and 52a are welded as in the examples shown in FIGS. 7 to 13, the outer cylinders 51a and 52a are configured as shown in FIG. A welding material 55 made of the same material as the material (for example, niobium) may be arranged on the facing portions 53 of the outer cylinders 51a and 52a to irradiate the electron beam EB.

As described above, the method of welding the double pipe according to the present embodiment has outer cylinders 51a and 52a and inner cylinders 51b and 52b centered on a predetermined central axis AX, and is one of the axial directions of the central axis AX. First structure 51 and second structure in which cleaning ports 44 and 45 for integrally fixing the outer cylinders 51a and 52a and the inner cylinders 51b and 52b are provided at the ends of the first structure and the other end in the axial direction is open. A method of welding a double pipe in which the other ends of the 52 in the axial direction are welded to each other to form a double pipe, and the first structure is such that at least the inner cylinders 51b and 52b are in contact with or close to each other. The other end of the object 51 and the other end of the second structure 52 are opposed to each other, and the outer cylinders 51a and 52a are side with respect to the first structure 51 and the second structure 52 arranged to face each other. Welding the inner cylinders 51b and 52b by irradiating an electron beam so as to penetrate or pass between the outer cylinders 51a and 52a and reach the facing portions of the inner cylinders 51b and 52b, and the facing arrangement. The outer cylinders 51a and 52a are welded to each other by irradiating the opposite portions of the outer cylinders 51a and 52a with an electron beam from the side of the outer cylinders 51a and 52a to the first structure 51 and the second structure 52. Including that.

Further, the double pipe welding device 100 according to the present embodiment has outer cylinders 51a and 52a and inner cylinders 51b and 52b centered on a predetermined central axis AX, and has one end in the axial direction of the central axis AX. The first structure 51 and the second structure 52 are provided with cleaning ports 44 and 45 for integrally fixing the outer cylinders 51a and 52a and the inner cylinders 51b and 52b, and the other end in the axial direction is open. A double-tube welding device 100 for forming a double-tube by welding the other ends in the respective axial directions to each other, and the first structure so that at least the inner cylinders 51b and 52b are in contact with each other or close to each other. It is arranged to face the structure holding portion 12 capable of holding the first structure 51 and the second structure 52 in a state where the other end of the 51 and the other end of the second structure 52 face each other. The electron beam irradiation unit 20 that irradiates the first structure 51 and the second structure 52 with an electron beam from the side of the outer cylinders 51a and 52a, and the structure holding unit 12 and the electron beam irradiation unit 20 are controlled. As a result, the inner cylinders 51b and 52b face each other through or pass between the outer cylinders 51a and 52a from the side of the outer cylinders 51a and 52a with respect to the first structure 51 and the second structure 52 arranged to face each other. The inner cylinders 51b and 52b are welded by irradiating an electron beam so as to reach the portion 54, and the outer cylinders 51a and 52a are outside the outer cylinders 51a and 52a with respect to the first structure 51 and the second structure 52 arranged to face each other. A control unit 30 is provided which irradiates the facing portions 53 of the cylinders 51a and 52a with an electron beam to weld the outer cylinders 51a and 52a.

According to the present embodiment, the inner cylinder penetrates or passes between the outer cylinders 51a and 52a from the side of the outer cylinders 51a and 52a with respect to the first structure 51 and the second structure 52 arranged to face each other. Cleaning ports 44 and 45 for fixing the outer cylinders 51a and 52a and the inner cylinders 51b and 52b are arranged to weld the inner cylinders 51b and 52b by irradiating the electron beam so as to reach the facing portions of the 51b and 52b. Even in this case, it is not necessary to irradiate the electron beam so as to bypass the cleaning ports 44 and 45, and by irradiating the electron beam from the side of the outer cylinders 51a and 52a, the outer cylinders 51a and 52a and the inner cylinder are irradiated. Welding of 51b and 52b can be performed. This makes it possible to easily perform the welding work.

In the method of welding a double tube according to the present embodiment, the double tube is a 1/2 wavelength resonator. The 1/2 wavelength resonator is provided with cleaning ports 44 and 45 at both ends in the axial direction of the central axis AX. It is difficult to irradiate and weld an electron beam so as to bypass the cleaning ports 44 and 45, but in the present embodiment, even if such irradiation is not performed, from the side of the outer cylinders 51a and 52a. By irradiating the electron beam, the outer cylinders 51a and 52a and the inner cylinders 51b and 52b can be welded.

In the method of welding the double pipes according to the present embodiment, when the inner cylinders 51b and 52b are welded to each other, the inner cylinders 51b and 52b are made to penetrate a part of the electron beam irradiating the facing portions of the outer cylinders 51a and 52a. Reach the opposite parts of each other. As a result, the outer cylinders 51a and 52a and the inner cylinders 51b and 52b can be welded at the same time by irradiating the electron beam once.

In the double pipe welding method according to the present embodiment, when the other ends are opposed to each other, the distance between the outer cylinders 51a and 52a facing each other is larger than the distance between the inner cylinders 51b and 52b facing each other. When the inner cylinders 51b and 52b are welded to each other, the double-tube structure is formed so as to pass between the outer cylinders 51a and 52a so that the electron beam reaches the facing portion between the inner cylinders 51b and 52b. .. As a result, the inner cylinders 51b and 52b can be easily welded by irradiating the electron beam from the side of the outer cylinders 51a and 52a.

In the double tube welding method according to the present embodiment, when the inner cylinders 51b and 52b are welded to each other, the electrons are set so that the distance between the outer cylinders 51a and 52a facing each other becomes smaller than the diameter of the electron beam due to welding shrinkage. The beam is applied to the inner cylinders 51b and 52b. In this configuration, by utilizing the welding shrinkage when welding the inner cylinders 51b and 52b to each other and shortening the distance between the outer cylinders 51a and 52a, the outer cylinders 51a and 52a do not change the diameter of the electron beam. The 52a and the inner cylinders 51b and 52b can be welded.

In the double pipe welding method according to the present embodiment, when the other ends are opposed to each other, the distance between the outer cylinders 51a and 52a facing each other is larger than the distance between the inner cylinders 51b and 52b facing each other. When the inner cylinders 51b and 52b are welded to each other, the outer cylinders 51a and 52a are formed so that the diameter of the electron beam is smaller than the distance between the outer cylinders 51a and 52a and the outer cylinders 51a and 52a. When the inner cylinders 51b and 52b are irradiated with an electron beam by passing between 52a and the outer cylinders 51a and 52a are welded to each other, the diameter of the electron beam is larger than that when the inner cylinders 51b and 52b are irradiated. The outer cylinders 51a and 52a are irradiated with an electron beam. As a result, the inner cylinders 51b and 52b can be easily welded by irradiating the electron beam from the side of the outer cylinders 51a and 52a. Further, after welding the inner cylinders 51b and 52b, the outer cylinders 51a and 52a can be welded from the same direction.

In the method of welding a double pipe according to the present embodiment, when the other ends are opposed to each other, the position of the facing portion between the outer cylinders 51a and 52a and the position of the facing portion between the inner cylinders 51b and 52b are the centers. A double-tube structure is formed so as to be displaced in the axial direction of the axis AX, and the facing portion between the outer cylinders 51a and 52a is formed so as to be inclined toward the facing portion between the inner cylinders 51b and 52b. When the 51b and 52b are welded to each other, the electron beam is passed between the outer cylinders 51a and 52a in the inclination direction of the facing portion so that the electron beam reaches the facing portion between the inner cylinders 51b and 52b. As a result, the inner cylinders 51b and 52b can be easily welded by irradiating the electron beam from the side of the outer cylinders 51a and 52a. Further, in the superconducting accelerator 40 formed after welding, the protruding portion 41b and the protruding portion 42b due to the welded portion are displaced in the axial direction of the central axis AX. In this case, the distance d4 between the protrusion 41b and the protrusion 42b is larger than the distance d3 between the protrusion 41b and the protrusion 49b when the virtual welded portion 49a is provided, so that the electric field is concentrated. It is suppressed.

In the method of welding the double pipes according to the present embodiment, when the outer cylinders 51a and 52a are welded to each other, the welding material 55 made of the same material as the outer cylinders 51a and 52a is applied to the facing portions of the outer cylinders 51a and 52a. It is placed in and irradiates an electron beam. As a result, the outer cylinders 51a and 52a can be easily and surely welded.

The technical scope of the present invention is not limited to the above-described embodiment, and modifications can be made as appropriate without departing from the spirit of the present invention. For example, in the above embodiment, the configuration in which the slit SL is used when reducing the diameter of the electron beam EB has been described, but the present invention is not limited to this. For example, by controlling the irradiation unit 21, the diameter of the electron beam EB may be changed depending on whether the inner cylinders 51b and 52b are irradiated and the outer cylinders 51a and 52a are irradiated.

Further, in the above embodiment, the case where the double tube is a 1/2 wavelength type resonator has been described as an example, but the present invention is not limited to this. The double pipe is provided with a structure for integrally fixing the outer cylinder and the inner cylinder at one end in the axial direction of the central axis, and the other is provided as long as the other end in the axial direction is open. It may be a structure.

10 Chamber 11 Stage 12 Structure holding unit 20 Electron beam irradiation unit 21 Irradiation unit 22 Imaging unit 30 Control unit 40 Superconducting accelerator 41 Acceleration cavity 41a Inner surface 41b, 42b, 49b Protruding part 42 Stem 42a Outer surface 43 Beam tube 44, 45 Cleaning Ports 46, 47, 48, 49 Welded part 49a Virtual welded part 51 First structure 51a, 52a Outer cylinder 51b, 52b Inner cylinder 51c, 52c Opposing part 52 Second structure 53, 54 Opposing part 55 Welding material 100 Welding Device B Charged particle beam EB, EBa, EBb Electron beam d1, d2, d3, d4 Distance AX Central axis SL Weld

Claims (9)

A structure having an outer cylinder and an inner cylinder centered on a predetermined central axis and integrally fixing the outer cylinder and the inner cylinder at one end in the axial direction of the central axis is provided, and the axial direction is provided. It is a method of welding a double pipe to form a double pipe by welding the other ends in the axial direction of each of the two double pipe structures having the other end open.
Of the two double-tube structures, the other end of the first structure and the other end of the second structure are opposed to each other so that at least the inner cylinders are in contact with each other or close to each other.
Electrons so as to penetrate or pass between the outer cylinders from the side of the outer cylinders and reach the facing portions of the inner cylinders with respect to the first structure and the second structure arranged to face each other. By irradiating the beam and welding the inner cylinders together,
To weld the outer cylinders to each other by irradiating the facing portions of the outer cylinders with the electron beam from the side of the outer cylinders to the first structure and the second structure arranged to face each other. Double pipe welding method including. The method for welding a double tube according to claim 1, wherein the double tube is a 1/2 wavelength resonator. 2. The second aspect of claim 1 or 2, wherein when the inner cylinders are welded to each other, a part of the electron beam that irradiates the facing portions of the outer cylinders is penetrated to reach the facing portions of the inner cylinders. Welding method for heavy pipes. The double pipe structure is formed so that the distance between the outer cylinders facing each other is larger than the distance between the inner cylinders facing each other when the other ends are opposed to each other.
The method for welding a double tube according to claim 1 or 2, wherein when the inner cylinders are welded to each other, the electron beam is passed between the outer cylinders to reach the facing portion of the inner cylinders. 2. According to claim 4, when the inner cylinders are welded to each other, the inner cylinder is irradiated with the electron beam so that the distance between the outer cylinders facing each other becomes smaller than the diameter of the electron beam due to welding shrinkage. Welding method for heavy pipes. The double pipe structure is formed so that the distance between the outer cylinders facing each other is larger than the distance between the inner cylinders facing each other when the other ends are opposed to each other.
When welding the inner cylinders to each other, the inner cylinders are irradiated with the electron beam by passing between the outer cylinders in a state where the diameter of the electron beam is narrowed down to be smaller than the distance between the facing portions of the outer cylinders. And
The double according to claim 1 or 2, wherein when the outer cylinders are welded to each other, the outer cylinder is irradiated with the electron beam in a state where the diameter of the electron beam is larger than that when the inner cylinder is irradiated. Welding method of pipe. When the other ends are opposed to each other, the double pipe structure is arranged so that the position of the facing portion between the outer cylinders and the position of the facing portion between the inner cylinders are displaced in the axial direction of the central axis. It is formed so that the facing portions of the outer cylinders are inclined toward the facing portions of the inner cylinders.
According to claim 4, when the inner cylinders are welded to each other, the electron beam is passed between the outer cylinders in the inclination direction of the facing portion so that the electron beam reaches the facing portion between the inner cylinders. Item 6. The method for welding a double pipe according to any one of items 6. When welding the outer cylinders to each other, any one of claims 4 to 7 in which a welding material of the same material as the material constituting the outer cylinders is arranged at a portion facing the outer cylinders and the electron beam is irradiated. The method for welding a double pipe according to item 1. A structure having an outer cylinder and an inner cylinder centered on a predetermined central axis and integrally fixing the outer cylinder and the inner cylinder at one end in the axial direction of the central axis is provided, and the axial direction is provided. A double-tube welding device for forming a double-tube by welding the other ends of the two double-tube structures with their other ends open in the axial direction.
In a state where the other end of the first structure and the other end of the second structure of the two double-tube structures face each other so that at least the inner cylinders are in contact with each other or close to each other. A structure holding portion capable of holding the first structure and the second structure, and
An electron beam irradiating unit that irradiates an electron beam from the side of the outer cylinder to the first structure and the second structure arranged to face each other.
By controlling the structure holding portion and the electron beam irradiation portion, the first structure and the second structure arranged to face each other penetrate between the outer cylinders from the side of the outer cylinders. Alternatively, the inner cylinders are welded by irradiating an electron beam so as to pass through and reach the facing portions of the inner cylinders, and the outer cylinders are formed with respect to the first structure and the second structure arranged to face each other. A double-tube welding device including a control unit that irradiates an electron beam on a portion facing each other from the side of the cylinder to weld the outer cylinders to each other.

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