JP2002174364A - Positioning device of pipe and positioning method of pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positioning device and positioning method of pipe capable of performing a precise positioning of a new pipe to an existing pipe in a short time without requiring much labor and improving the efficiency of positioning work. SOLUTION: A laser beam oscillator 25 for generating a visible laser beam is provided on one end part 22 of the existing pipe 21. A first target 31 having a transmission part 29 is provided on the other end part 28 of the new pipe 27. A second target 34 having a light receiving part 33 is provided on one end part 32 of the new pipe 27. The new pipe 27 is moved so that the laser beam is emitted from the laser beam oscillator 25, transmitted by the transmission part 29 of the first target 31, and irradiated to the light receiving part 33 of the second target 34. Accordingly, beveling precision preliminarily determined in a material storage space can be reproduced in the laying site of a pipeline.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for forming a pipeline for transporting a fluid such as gas by connecting a new pipe to an existing pipe previously laid by electron beam welding, laser beam welding or the like. The present invention relates to a pipe positioning device and a pipe positioning method that can be suitably implemented to accurately position and arrange a pipe at a predetermined position with respect to an existing pipe.

[0002]

2. Description of the Related Art FIG. 11 is a diagram showing a state in which pipes 1 and 2 are butted from side to side for explaining a conventional technique.
FIG. 12 is an enlarged sectional view of section X in FIG. For example, when laying a pipeline for transporting a fluid such as a gas, the work of butt-welding a new pipe 2 as a second pipe to an existing pipe 1 as a first pipe already laid and sequentially connecting the pipes is repeated. It is. One end 3 of the existing pipe 1 in the pipe axis direction
, The other end 4 of the new pipe 2 in the pipe axis direction facing the one end 3 is grooved, and one end face 5 of the existing pipe 1 is cut perpendicular to the axis of the one end 3 of the existing pipe 1. The other end surface 6 of the new pipe 2 is cut perpendicular to the axis of the other end 4 of the new pipe 2.

[0003] The pipe axis defined in this specification refers to an axis extending through the center of the pipe and along the longitudinal shape of each of the pipes 1 and 2, and the axis defined in this specification is defined as the axis of the pipe. It refers to an axis that extends perpendicular to each end face in the tube axis direction and passes through the center of each end face.

[0004] A root gap G1, which is an interval between the end surfaces 5, 6 along the direction of an axis (an axis perpendicular to the end surfaces 5, 6) at each of the end portions 3, 4, and an inner peripheral surface of each of the tubes 1, 2 7,8
The amount of misalignment G, which is the amount of deviation in the direction perpendicular to each axis
2 determines the groove accuracy required for the butt 9 between the existing pipe 1 and the new pipe 2, and the smaller the variation in the groove accuracy in the circumferential direction, the higher the groove accuracy of the butt 9. .

[0005] Such groove accuracy differs depending on the type of welding for joining the butting portions 9. This welding is
Butt welding, for example, MAG (Metal Active G
as), MIG (Metal Inert Gas) and TIG (Tungs
For example, high energy density welding such as electron beam welding and laser beam welding, which have a high welding speed, is widely used to improve the efficiency of welding work.

In such high energy density welding, for example, in electron beam welding, the beam diameter of the electron beam applied to the butt 9 of the existing pipe 1 and the new pipe 2 is small. When welding by irradiating an electron beam from the tube, the groove of each end 3, 4 of the butting portion 9 of each tube 1, 2 is set to I groove, and the root gap G1 is formed.
Needs to be maintained at, for example, 0.2 mm or less and the misalignment amount G2 is at 2.5 mm or less, for example.

For this reason, at the time of cutting for forming the groove surfaces 5, 6 of the end portions 3, 4 of the tubes 1, 2, the tubes 1, 2,
The end portions 3 and 4 of the tubes 1 and 4 are cut into a perfect circular shape as much as possible, and a cutting process is performed. A correction jig is attached to correct the ends 3 and 4 of the tubes 1 and 2 to a perfect circle, that is, to a perfect circle in the same state as in the cutting process. At this time,
One end face of the circularity correction jig attached to the existing pipe 1 is arranged in parallel with one end face 5 of the existing pipe 1, and the other end face of the circularity correction jig to which the new pipe 2 is attached is connected to the other end of the new pipe 2. End face 6
Are arranged in parallel to The jig for roundness correction on the existing pipe 1 side and the jig for roundness correction on the new pipe 2 side are configured as a pair, and the mutually facing end faces are strictly parallel to each other. It has been processed. Thereafter, a seal ring is attached to a portion of the end 4 of the new pipe 2 protruding from the jig for roundness correction, and the new pipe 2 suspended from the bogie on the ground and the axis of the other end 4 are connected to the existing pipe. 1 is moved to a position substantially coaxial with the axis of the one end 3.

Next, the jigs for the new pipe side roundness correction jigs provided at both ends in the pipe axis direction of the new pipe 2 are inserted through the mounting holes of the clamp jacks provided in the respective roundness correction jigs on the existing pipe 1 side. After visually checking the mounting holes of the clamp jacks and moving the new pipe 2 up and down and left and right while checking the deviation, and adjusting the position of the new pipe 2 with respect to the existing pipe 1, Jigs for straightening are connected to each other and a new pipe 2
The jig for roundness correction on the other end side of the existing pipe 1 is drawn by a plurality of clamp jacks provided on the jig for roundness correction, and the root gap G1 is set to 0.2 m as described above.
m, the new pipe 2 is positioned at a position where a predetermined groove accuracy can be obtained with respect to the existing pipe 1.

After the positioning operation of the tubes 1 and 2 is completed, the electron beam welding apparatus already housed in the existing tube 1 in the previous welding is moved between the end portions 3 and 4 of the tubes 1 and 2. To reduce the pressure in the outer space between the outer peripheral surfaces 7 and 8 of the tubes 1 and 2 and the seal ring and the inner space between the inner peripheral surfaces of the tubes 1 and 2 and the electron beam welding apparatus. Then, the butting portion 9 from the inside by the electron beam welding device.
The entire pipe is irradiated with an electron beam to form a butt welding joint, and the new pipe 2 is connected to the existing pipe 1.

[0010]

In such a conventional technique, the positioning of the new pipe 2 with respect to the existing pipe 1 is visually performed by an operator using the mounting holes of the clamp jacks of the jig for correcting roundness. Therefore, in the case of electron beam welding or the like that requires high positioning accuracy, a lot of trouble and time are required for the positioning work of the newly installed pipe. In particular, when a new pipe is connected to an existing pipe buried underground such as a pipeline in an excavation trench, the worker cannot go under or on both sides of the existing pipe 1 and, therefore, cannot move upward. The work of visually confirming the positioning of the new pipe 2 must be performed only by the mounting holes to be arranged, and there is a problem that the efficiency of the positioning work is extremely low.

SUMMARY OF THE INVENTION An object of the present invention is to provide a tube positioning support apparatus which can position a new pipe with respect to an existing pipe with high accuracy in a short time without any trouble, thereby improving the efficiency of the positioning operation. It is to provide a method of positioning a tube.

[0012]

According to the present invention, there is provided a pipe positioning apparatus for positioning a relative position between a first pipe and a second pipe to be butt-welded, wherein the first pipe has a pipe axis. A laser beam generating means provided at one end of the first tube and generating a laser beam in a visible wavelength band perpendicular to the end face of the first tube in the tube axis direction; and one end of the second tube in the tube axis direction of the first tube A first target provided at the other end in the tube axis direction opposite to the portion and having a transmitting portion through which the laser beam can pass; and a first target provided at one end in the tube axis direction of the second tube and irradiated with the laser beam. The second having a light receiving section
A tube positioning device, comprising: a target;

According to the present invention, the pipe positioning device is suitably implemented when a plurality of pipes are butt-welded to form a pipeline. At one end of the existing pipe, which is the first pipe, in the pipe axis direction, a laser beam generating means for generating a laser beam in a visible wavelength band perpendicular to the end face of the existing pipe in the pipe axis direction is provided. In addition, a first target having a transmission portion through which the laser beam can pass is provided at the other end in the tube axis direction of the new tube, which is the second tube, opposite to one end in the tube axis direction of the existing tube. Further, a second target having a light receiving unit to be irradiated with the laser beam is provided at one end of the new pipe in the pipe axis direction.

Next, a description will be given of a method of positioning a pipe by the pipe positioning apparatus having the above-described configuration. For example,
A case where a new pipe is butt-welded to an existing pipe by electron beam welding to form a pipeline will be described. Before laying the first pipe to be an existing pipe at the pipeline laying site, the above-mentioned first pipe is stored in a material storage place or a factory.
The new pipe, which is a new pipe to be butt-welded to the first pipe, is pre-groove-processed or formed accurately in advance so that the root gap has a groove accuracy of 0.2 mm or less and the misalignment amount is 2.5 mm or less. Adjust the groove accuracy. Such a groove processing method and a groove precision adjusting method are described in Japanese Patent Application No. 2000-114019 filed by the present applicant.

As described above, while maintaining the groove accuracy of each tube, the laser beam generated from the laser beam generating means provided at one end of the first tube in the tube axis direction is transmitted to the second tube. The transmission part of the first target provided at the other end in the axial direction is transmitted, and the laser beam transmitted through the transmission part of the first target is transmitted to the second end provided at one end of the second tube in the axial direction of the second tube.
Irradiate the light receiving part of the target. In this state, the laser beam generating means is fixed to the first tube, and the first and second targets are fixed to the second tube. In particular, when the first pipe and the second pipe are transported to the pipeline laying site, the position of the laser beam generating means with respect to the first pipe and the positions of the first and second targets with respect to the second pipe do not shift. So as to fix it.

Next, the first pipe having the laser beam generating means adjusted as described above and the second pipe to which the first and second targets are fixed are transported to the pipeline laying site. Next, the first pipe and second pipe at the pipeline laying site
A method of positioning the pipe relative to the pipe will be described. Here, the other end of the first pipe is butt-welded to form an existing pipe, and the new pipe, which is the second pipe formed by beveling the existing pipe, is positioned.

A laser beam is generated from a laser beam generating means provided on the existing pipe toward a laying area of the new pipe, and this laser beam is applied to a first target of the new pipe suspended on a truck or the like. Irradiated. The operator moves the other end of the new pipe in the tube axis direction up, down, left, and right so that the laser beam passes through the transmission part of the first target. In this way, the other end of the new pipe in the pipe axis direction can be positioned with respect to the one end of the existing pipe in the pipe axis direction.
That is, positioning is performed so that one end of the existing pipe in the pipe axis direction and the other end of the new pipe in the pipe axis direction are coaxial. The pipe axis defined in the present specification is an axis extending along the longitudinal shape of the existing pipe and the new pipe, and the axis defined in the present specification extends perpendicular to each end face of the pipe, and Refers to the axis passing through the center of

Next, the light receiving section of the second target provided at one end of the new pipe in the pipe axis direction is irradiated with the laser beam transmitted through the transmission section of the second target in the pipe axis direction of the new pipe. By lowering one end and moving one end in the pipe axis direction up and down and left and right similarly to the other end in the pipe axis direction of the new pipe, the new pipe is positioned so as to be coaxial with the existing pipe. In this state, by pulling the new pipe in the direction adjacent to the existing pipe by a jig for roundness correction similar to the conventional technique, at the pipeline laying site,
The groove accuracy at the time of groove processing in the material storage and factory is reproduced.

The laser beam generating means provided on the existing pipe as described above and the laser beam generating means provided on both ends in the pipe axis direction of the new pipe are provided.
With the use of two targets, the new pipe can be positioned with respect to the existing pipe, so that the operator only needs to adjust the position of the new pipe while checking the irradiation state of the laser beam to each target. Compared to the case of using a part that does not have a configuration for positioning such as a mounting hole of a clamp jack of a roundness jig as in the conventional technique, an unnatural posture, and from a plurality of different places This eliminates the need for confirmation work for positioning, thus improving the workability and enabling the new pipe to be positioned with high precision in a short time without any trouble. Efficiency is improved.

Further, since the laser beam generated by the laser beam generating means is a laser beam in a visible wavelength band, the irradiation position of the laser beam on each target even in dark conditions such as cloudy or sunset. Are displayed continuously, and when the irradiation position is desired, the irradiation position can be easily and clearly recognized, thereby preventing erroneous recognition.

Furthermore, since the eccentricity of the irradiation position of the laser beam with respect to the transmitting portion and the light receiving portion of each target can be recognized, the movement of the new pipe required for positioning the new pipe coaxially with the existing pipe. The quantities can be determined simultaneously. Therefore, the operator only has to move the newly installed pipe by a distance in which the irradiation position of the laser beam to each target is shifted in the direction approaching the transmitting part and the light receiving part, and the efficiency of the positioning operation can be remarkably improved.

According to a second aspect of the present invention, there is provided a pipe positioning method for positioning a relative position between a first pipe and a second pipe to be butt-welded, the method being provided at one end of the first pipe in a pipe axis direction. A laser beam in a visible wavelength band is generated from a laser beam oscillator in a direction perpendicular to the end face of one end of the first tube in the tube axis direction, and a tube axis of the second tube facing one end of the first tube in the tube axis direction. The transmission part of the first target provided at the other end of the second tube is moved at the other end of the second tube in the tube axis direction so as to transmit the laser beam, and provided at one end of the second tube in the tube axis direction. Moving the one end of the second tube in the tube axis direction so that the light receiving portion of the second target is irradiated with the laser beam transmitted through the transmitting portion of the first target. .

According to the present invention, a laser beam oscillator is provided at one end in the tube axis direction of the first tube which is an existing tube, and the laser beam oscillator is provided on one end of the first tube in the tube axis direction. Vertically, a laser beam in the visible wavelength band is oscillated. In the second pipe to be a new pipe, a first target is provided at the other end of the first pipe in the pipe axis direction opposite to one end of the first pipe in the pipe axis direction. , A second target. The first target has a transmitting part of the laser beam, and the second target has a light receiving part of the laser beam. For example, a case where a new pipe is butt-welded to an existing pipe by electron beam welding to form a pipeline will be described.

Next, a description will be given of a pipe positioning method using the pipe positioning apparatus having the above-described configuration. Before laying the first pipe that will be the existing pipe at the pipeline laying site,
In a material storage place or a factory, the first pipe and the second pipe which is a new pipe butt-welded to the first pipe are
Root gap less than 0.2mm, misalignment 2.5m
Groove machining or groove precision adjustment is performed accurately in advance so as to have a groove precision of m or less. Such a groove processing method and a groove precision adjusting method are described in Japanese Patent Application No. 2000-114019 filed by the present applicant.

As described above, while maintaining the groove accuracy of each tube, the laser beam generated from the laser beam generating means provided at one end of the first tube in the tube axis direction is applied to the second tube. The transmission part of the first target provided at the other end in the axial direction is transmitted, and the laser beam transmitted through the transmission part of the first target is transmitted to the second end provided at one end of the second tube in the axial direction of the second tube.
Irradiate the light receiving part of the target. In this state, the laser beam generating means is fixed to the first tube, and the first and second targets are fixed to the second tube. In particular, when the first pipe and the second pipe are transported to the pipeline laying site, the position of the laser beam generating means with respect to the first pipe and the positions of the first and second targets with respect to the second pipe do not shift. So as to fix it.

Next, the first pipe to which the laser beam generating means is fixed and the second pipe to which the first and second targets are fixed are transported to the pipeline laying site. Next, the first pipe and second pipe at the pipeline laying site
A method of positioning the pipe relative to the pipe will be described. Here, it is assumed that the other end of the first pipe is butt-welded to form an existing pipe, and a new pipe, which is a second pipe formed by beveling the existing pipe, is positioned.

The new pipe on which the first target and the second target are provided is first moved at the other end in the axial direction of the pipe on which the first target is provided, so that the laser beam passes through the transmitting portion of the first target. The other end of the new pipe in the pipe axis direction is positioned. Next, one end in the tube axis direction of the new tube is moved so that the light receiving portion of the second target is irradiated with the laser beam transmitted through the transmission portion of the first target. Position the side.

As described above, the new pipe can be positioned with respect to the existing pipe by using the laser beam oscillator provided on the existing pipe and the two targets provided at both ends in the pipe axis direction of the new pipe. The operator may adjust the position of the new pipe, the other end in the pipe axis direction, and the one end in the pipe axis direction in this order while checking the irradiation state of the laser beam to each target. In comparison with the above, there is no need to perform a positioning check operation in an unnatural posture and from a plurality of different places, so that the amount of movement of the operator is small, and the new pipe requires much time and effort with respect to the existing pipe. Without this, positioning can be performed with high accuracy in a short time, and the efficiency of the positioning operation is improved.

Further, since the laser beam generated from the laser beam oscillator is a laser beam in the visible wavelength band, the irradiation position of the laser beam on each target can be adjusted even in dark conditions such as cloudy sky or sunset. It is displayed continuously, and when the irradiation position is desired, it can be easily and clearly recognized, thereby preventing erroneous recognition.

Furthermore, since the amount of eccentricity of the irradiation position of the laser beam with respect to the transmitting portion and the light receiving portion of each target can be recognized, the movement of the new pipe necessary for coaxially positioning the new pipe with respect to the existing pipe. The quantities can be determined simultaneously. Therefore, the operator only has to move the new pipe in a direction in which the irradiation position of the laser beam to each target approaches the transmitting part and the light receiving part, and the efficiency of the positioning operation can be remarkably improved.

[0031]

FIG. 1 is a sectional view showing a tube positioning apparatus 20 according to an embodiment of the present invention, and FIG.
FIG. 3 is a plan view of the laser beam generating means 26 as viewed from above, and FIG.
6 is a side view, and FIG.
First, the mechanical configuration of the tube positioning device 20 will be described.

The pipe positioning device 20 according to the present embodiment comprises:
Pipe axis direction of the existing pipe 21 as the first pipe (left-right direction in FIG. 1)
A laser beam generating means 26 provided at one end 22 and having a laser beam oscillator 25 for generating a laser beam in a visible wavelength band having an optical axis 24 perpendicular to an end face 23 of the one end 22 of the existing pipe 21 in the tube axis direction; A second tube, which is provided at a second end portion 28 of the new tube 27 which is opposite to the one end portion 22 of the existing tube 21 in the axial direction of the existing tube, and has a transmitting portion 29 through which the laser beam can pass. It includes a first target 31 and a second target 34 provided at one end 32 of the new pipe 27 in the pipe axis direction and having a light receiving section 33 to which the laser beam is irradiated.

In such a positioning device 20, for example, in the construction work of a pipeline for transporting a fluid such as a gas, a new pipe 27 is butt-welded to an existing pipe 21 which has already been laid by electron beam welding, and sequentially. When connecting to the existing pipe 21, the new pipe 27 is
Is used to position the groove with a predetermined groove accuracy. As a pipe used for constructing such a pipeline, a seamless steel pipe having a long pipe length is generally used, and thus has a shape curved in the longitudinal direction (the left-right direction in FIG. 4) as shown in FIG. As shown in FIG. 4, the pipe axis defined in the present embodiment refers to the axis 150 that passes through the center of the pipe 151 and extends along the curve in the longitudinal direction of the pipe 150, and the axis refers to the axis of the pipe 151. The axis 150 extends perpendicular to each end face of the tube axis 150 and passes through the center of each end face. Existing pipe 2
Since the beam diameter of the electron beam applied to the butting portion 38 of the first tube 27 and the new tube 27 is small, when the butting portion 38 is irradiated with the electron beam from inside and welded,
The groove of each end 22, 28 of the butting portion 38 of 1, 27 is
It is necessary to keep the root gap G1 at 0.2 mm or less and the misalignment amount G2 at 2.5 mm or less over the entire surface of each of the end faces 23 and 35 with respect to the existing pipe 27. There is.

Since it is necessary to maintain the above groove accuracy at the time of butt welding of tubes by electron beam welding, a first perfect circular ring 41 is provided at one end 22 of the existing tube 21 in the tube axis direction. The other end 28 of the new pipe 27 in the pipe axis direction
Is provided with a second perfect circle ring 42, and the ends 22, 28 are corrected by the perfect circular rings 41, 42 into a perfect circle equivalent to the shape of the groove. Thereafter, the second perfect circular ring 42 at the other end 28 of the new pipe 21 in the pipe axis direction is used.
Pulling cylinders 106a to 106c projecting from
The seal ring 43 is attached, and the new pipe 27 is suspended from a bogie (not shown), and is disposed near the existing pipe 21 such that the ends 22 and 28 face each other.

The laser beam generating means 26 includes a laser beam oscillator 25, an optical axis adjusting jig 44 for holding the laser beam oscillator 25, and an optical axis adjusting jig 44, which are arranged in a horizontal direction perpendicular to the plane of FIG. And a horizontal moving jig 45 that is supported so as to be movable in the direction. The laser beam oscillator 25
Is also referred to as a laser pointer, has a substantially cylindrical shape, and has a laser source such as a laser diode (abbreviated as LD) and a laser beam oscillated from the laser source having a predetermined beam diameter. And a lens optical system for collecting light.

As shown in FIG. 1, the optical axis adjusting jig 44
Is a mounting member 48 to which the laser beam oscillator 25 is penetrated and fixed in the thickness direction (the left-right direction in FIG. 1) near the upper end.
A hinge piece 49 fixed near the lower end of the mounting member 48; and a pitch angle adjusting bolt 50 as a hinge pin horizontally inserted through the free end of the one hinge piece 49.
The other hinge piece 51 connected to the one hinge piece 49 via the pitch angle adjusting bolt 50; a column 52 to which the other hinge piece 51 is fixed near the upper end; and a lower end of the column 52 Are fixed vertically, a base 54 for supporting the support piece 53, and a pair of horizontal angle adjusting bolts for fixing the support piece 53 on the base 54 in any direction on a horizontal plane. 55, a mounting piece 56 fixed to one side of the base 54, and a pair of mounting bolts 58 for fixing the mounting piece 56 to the mounting piece 57 of the horizontal moving jig 45.

The direction of the optical axis 24 of the laser beam oscillated from the laser beam oscillator 25 is adjusted by loosening the pitch angle adjusting bolt 50 so that the laser beam oscillator 25 and the mounting member 48 are moved together with the virtual horizontal plane 6.
1, the pitch angle α about the horizontal axis 62 can be varied. By loosening the horizontal angle adjusting bolt 55, the horizontal angle β about the vertical axis 63 of the laser beam oscillator 25 can be changed. With such a configuration, the optical axis 24 of the laser beam oscillated from the laser beam oscillator 25 is
2 can be adjusted and set so as to be parallel to the second axis.

As shown in FIG. 2, the horizontal moving jig 4
5 is a rail body 64 extending horizontally on an imaginary plane perpendicular to the axis of the one end 22 of the existing pipe 21;
The two legs 65 and 66 projecting downward (toward the back side of FIG. 2) at both ends in the longitudinal direction (left and right directions in FIG. 2), and in the directions of arrows A1 and A2 along the longitudinal direction of the rail body 64. A sliding member 67 movably provided, a lock bolt 68 for fixing the sliding member 67 at an arbitrary position on the rail main body 64, and a sliding member 67 of the rail main body 64 on a horizontal imaginary plane. A mounting body 70 fixed in an axial direction perpendicular to the axis, a bracket 71 whose upper end is fixed to one longitudinal end (right side in FIG. 2) of the mounting body 70 on the existing pipe 21 side, and a bracket 71 and the mounting piece 57 fixed to the lower end of the base 71.

A first through hole 72 through which a laser beam oscillated from the laser beam oscillator 25 can pass is formed in the upper portion of the bracket 71. The inner diameter of the first through hole 72 is selected to be, for example, 6.6 mm. An end plate 73 is fixed to the other end (the left side in FIG. 2) of the attachment body 70 on the new pipe 27 side in a direction perpendicular to the axis of the other end 28 of the new pipe 27. At the approximate center of the end plate 73, a second through hole 74 having a smaller diameter than the through hole 72 is formed. The inner diameter of the second through hole 74 is, for example, 5.0 mm.
Is chosen. By adjusting the direction of the laser beam oscillator 25 so that the laser beam from the laser beam oscillator 25 passes through such a second through hole 74,
As described above, the irradiation direction of the laser beam is adjusted so that the optical axis 24 is parallel to the axis of the one end 22 of the existing pipe 21 (the axis perpendicular to the one end surface 23 of the existing pipe 21). Can be adjusted before positioning.

As shown in FIG. 1, the first target 31
Is a target plate 81 having the transmission portion 29.
And one hinge piece 82 fixed to the lower end of the target plate 81, and an adjustment bolt 8 as a hinge pin horizontally inserted into the free end of the one hinge piece 82.
3, the other hinge piece 84 into which the adjustment bolt 83 is inserted, a support 85 to which the other hinge piece 83 is fixed at the upper end, and the lower end of the support 85 are connected to each other, and And a bracket 86 fixed to one side facing the one end 32 side in the tube axis direction.

A first perfect circular ring 87 is provided at one end 32 of the new pipe 27 in the pipe axis direction.
The second target 34 is provided on one side surface facing the other end 28 side in the tube axis direction. This second target 3
Reference numeral 4 denotes a target plate 91 having the light receiving section 33 and one hinge piece 9 fixed to the lower end of the target plate 91, similarly to the first target 31 described above.
2, an adjusting bolt 93 as a hinge pin connected to the free end of one hinge piece 92 so as to be angularly displaceable about the horizontal axis, and the other of the adjusting bolt 93 is connected to this adjusting bolt 93 so as to be angularly displaceable about the horizontal axis. A hinge piece 94, a support 95 to which the other hinge piece 94 is fixed at the upper end, and a lower end of the support 95 connected to one side facing the other end 28 of the perfect circular ring 87 in the tube axis direction. Bracket 9 fixed to the part
6 is included. Each of the target plates 81, 91
It is made of a light-shielding material that does not transmit the laser light.

FIG. 5 is an exploded perspective view of the first perfect circle ring 41, the second perfect circle ring 42, and the seal ring 43.
FIG. 6 is a right-angle cross-sectional view as viewed from the right in FIG. 4 with a part of the second perfect circle ring 42 cut away. First true circular ring 41 attached to one end 22 of the existing pipe 21 in the pipe axis direction
And a second attached to the other end of the new pipe 27 in the pipe axis direction.
The first perfect circular ring 4 is formed as a pair with the perfect circular ring 42.
Mutually opposed end faces 200 of the first and second perfect circle rings 42,
201 are processed to be strictly parallel.

The second perfect circle ring 42 includes a plurality of (three in this embodiment) divided structures 100a, 100b, 10
0c, each of the divided structures 100a to 100c has an inner peripheral side flange 101, an outer peripheral side flange 102, a web 103 connecting each flange 101, and each flange 1
01 and 102 and a pair of end plates 104 and 105 fixed to both circumferential ends of the web 103.

The pair of end plates 104 and 105 adjacent to each of the divided structures 100a to 100c in the circumferential direction are connected to each other by bolts and nuts (not shown) to form a substantially annular ring as a whole. Each divided structure 1
The drawing cylinders 106a to 106c
6c, and each of the pulling cylinders 106a to 106c
Are provided on each side in the circumferential direction. The pulling cylinders 106a to 106c are machined strictly perpendicularly to the end face 200 of the second perfect circular ring 42 facing the first perfect circular ring 41. Each pair of clamp cylinders 10
Press plates 109 for pressing the outer peripheral surface of the existing pipe 21 are provided at radially inner ends of the pipes 7 and 108, respectively. In addition, each pair of hanging protrusions 11 is vertically attached to each outer peripheral flange 102 of each of the divided structures 100a to 100c.
1, 112 protrude outward in the radial direction and are fixed.
Hook fittings 116, 117, which are engaged with ropes 114, 115, such as wire ropes, from a carriage 113 shown in FIG.
Around the hanging tools 118 and 119
It is configured so that it can be displaced up and down.

The first perfect circular ring 41 is formed with a fitting hole 121 to be described later instead of each of the pulling cylinders 106a to 106c of the second perfect circular ring 42,
An engaging plate 123 having an engaging hole 122 (see FIG. 1) which is long in the circumferential direction is fixed to the web 103 by a bolt or the like so as to close the web 103. The corresponding parts are denoted by the same reference numerals.

The structure of the first perfect circle 41 is as follows.
A first perfect circular ring 87 provided at one end 32 of the new pipe 27 in the pipe axis direction is also provided in the same manner, and the corresponding parts are denoted by the same reference numerals.

Each of the pulling cylinders 106a to 106c is
A piston rod 127 fixed to a piston that moves in the right-left direction in FIG. 1 within a straight cylindrical cylinder tube;
An engagement piece 128 fixed to an end of the piston rod 127 protruding from the cylinder tube. An inner screw (not shown) is formed on the inner peripheral portion of the cylinder tube so that the piston rod 127 rotates 90 ° in one direction after reaching a predetermined pushing position. An outer screw is formed to be screwed to the inner screw.

When the piston rod 127 is extended and reaches the stroke end extension limit, the engagement piece 128 is oriented in the longitudinal direction in the circumferential direction, and changes its orientation to the direction in which the engagement hole 122 is inserted. By moving the new pipe 27 in the direction approaching the existing pipe 21 in this direction, the engagement piece 128 passes through the engagement hole 122. Next, when the piston rod 127 is retracted, the engagement piece 128 rotates 90 ° in the opposite direction to the extension direction, and then engages with the web of the new pipe front end side perfect circular ring 42, and the new pipe 27 is installed. It is drawn in a direction approaching the tube 21. In this manner, the positioning is performed so that the root gap G1 becomes a predetermined value, for example, 0.2 mm or less in the case of electron beam welding.

FIG. 7 shows a carriage 113 for suspending the new pipe 27.
FIG. As described above, the second true ring 4 is attached to the other end 28 (right side in FIG. 7) of the new pipe 27 in the pipe axis direction.
2 is attached, and a first perfect circular ring 87 is attached to one end 32 in the tube axis direction. Each of the perfect circular rings 42 and 87 is provided with a pair of suspension locking pieces 130 and 131, and the pair of suspension locking pieces 111 is suspended from the front and rear portions of the carriage 113. Ropes 114, 11 such as wire ropes
The hook pieces 116 and 117 provided at the lower end of the hook 5 are hooked, and the front and rear ropes 114 and 115 are individually wound or unwound by winding means 137a and 137b provided on the bogie main body 136, and newly installed. The other end 28 in the axial direction and the one end 32 in the axial direction of the tube 27 are configured to be individually vertically movable.

At the lower part of the carriage body 136, a ground surface 138 is provided.
A pair of front and rear wheels 139 and 140 for traveling the vehicle are provided, and a state in which the excavation groove 141 excavated for laying the new pipe 27 is straddled in the width direction perpendicular to the paper surface of FIG.
It can move in the left-right direction of FIG. Each cord 11
The pair of front and rear telescopic arms 142 and 143 are used to suspend the perfect circular rings 42 and 87 fixed to both ends 28 and 32 of the new pipe 27 in the axial direction. It is provided on the upper part of the bogie main body 136.
At the tip of each telescopic arm 142, 143,
The take-up means 137a, 137b of 14 and 115 are hooked, and the base end of each of the telescopic arms 142 and 143 can move on the upper part of the bogie main body 136 in the width direction perpendicular to the paper surface of FIG. 144 holds. The moving body 144 is moved so that the new pipe 27 is arranged substantially on the same axis as the existing pipe 21.

The movement of the movable body 144 in the width direction perpendicular to the paper surface of FIG. 7 is performed by lateral movement cylinders 147a and 147b provided on both front and rear sides of the bogie main body 136. Elongation and retraction are
Cylinder 148 for forward and backward movement provided on moving body 144
a, 148b. Each cylinder 147a,
147b; 148a, 148b are realized by, for example, a double-acting hydraulic cylinder.

Next, the positioning device 2 having the above configuration
How to use 0 will be described. FIG. 8 is a diagram illustrating a target adjustment method. Referring to FIG. 8, an existing pipe 21 (an existing pipe before butt welding) before being transported to a pipeline laying site in a material storage place or a factory.
And the root gap between the new pipe 27 to be connected to the existing pipe 21 is 0.2 mm or less, and the misalignment amount is 2.5 m.
m is precisely grooved beforehand so that the groove accuracy is less than m.
And the axis of one end 22 of the existing pipe 21 in the pipe axis direction and the new pipe 2
7 so that the axis of the other end 28 of the tube 7 is coaxial.
27 is adjusted. Such a groove forming method and a position adjusting method are described in Japanese Patent Application No.
Since it is described in 00-114019, detailed description is omitted here. Here, in the present application, the above-mentioned Japanese Patent Application No.
It is specified that all the contents described in 00-114019 are included.

Next, in a state where the existing pipe 21 and the new pipe 27 maintain a mutual positional relationship so as to achieve the above-described groove accuracy, a first perfect circular ring is attached to one end 22 of the existing pipe 21 in the pipe axis direction. 41 is fixed to the other end 28 of the new pipe 27 in the pipe axis direction.
A second perfect circle ring 42 composed of a pair is fixed to the first perfect circle ring 41. At this time, the first perfect circular ring 41 is attached to the existing pipe 21 so that the end face 201 of the first perfect circular ring 41 facing the new pipe 27 and one end face 203 of the existing pipe 21 in the pipe axis direction are strictly parallel. Fix it. Also, the end surface 200 of the second perfect circle ring 42 facing the existing pipe 21 and the other end face 204 of the new pipe 27 in the pipe axis direction are strictly parallel to each other.
The second perfect ring 42 is fixed to the new pipe 27. Thus, the pulling cylinder 106a is connected to the axis of one end 22 of the existing pipe 21 in the pipe axis direction and the other end 2 of the new pipe 27 in the pipe axis direction.
8 and strictly parallel to the eight axes. This state is shown in FIG.

Next, as shown in FIG. 8 (2), the above-described mounting member 70 is mounted on the pulling cylinder 106a.
As described above, since the pulling cylinder 106a is disposed parallel to the axis of the one end 22 of the existing pipe 21 and the other end 27 of the new pipe 27, the first through hole 72 and the second The line connecting the hole 74 is parallel to the axis of the one end 22 of the existing pipe 21 and the other end 27 of the new pipe 27. Thereafter, the position of the laser beam oscillator 25 is adjusted so that the laser beam oscillated from the laser beam generating means 26 passes through the first through hole 72 and the second through hole 74 of the mounting body 70, and in this state, the pitch is adjusted. Angle adjustment bolt 50
And the horizontal angle adjusting bolt 55 (see FIG. 1).
The laser beam oscillator 25 is fixed so as not to move. In particular, when the existing pipe 21 is transported to the pipeline laying site, the position of the laser beam oscillator 25 is fixed so that the position does not shift. As a result, the laser beam oscillated from the laser beam generating means is applied to one end face 2 of the existing pipe 21.
3 travels parallel to the axis.

Next, as shown in FIG.
The position of the target plate 81 (see FIG. 1) is adjusted so that the laser beam transmitted through the first through hole 72 and the second through hole 74 of the first target 31 passes through the transmitting portion 29 of the first target 31. Tighten the adjusting bolt 82 to fix the target plate 81 so as not to move. In particular, when transferring the new pipe 27 to the pipeline laying site,
The target plate 81 is fixed so that the position does not shift. As described above, the operations shown in FIGS. 8A to 8C are performed once before the first groove alignment, and are performed at the time of maintenance such as when the positions are shifted.

When the pipe is normally laid repeatedly, since the existing pipe 21 is laid, the laser generating means 26 is fixed to the mounting body 70 as shown in FIG.
The target plate 91 (so that the laser beam transmitted through the first through-hole 72 and the second through-hole 74 of the mounting body 70 and the light-transmitting portion 29 of the first target 31 is received by the light-receiving portion 33 of the second target 34). 1), and in this state, the adjustment bolt 92 is tightened to fix the target plate 91 so as not to move. In particular, when the new pipe 27 is transferred to the pipeline laying site, the target plate 91 is fixed so that the position does not shift. The end surface of the mounting body 70 and the end surface of the perfect circle ring 41 are machined so as to be strictly parallel.

As described above, the laser generating means 26 is fixed to the attachment 70 when adjusting the position of the second target 34 of the new pipe 27, and is fixed to the perfect circular ring 41 of the existing pipe 21 when aligning the groove. After that, the first target 31 and the second target 34 are transported to the pipeline laying site while being fixed to the new pipe 27.

FIG. 9 is a flowchart showing a procedure of a pipe positioning method using the positioning device 20, and FIG.
FIG. 10A is a simplified cross-sectional view showing a state in which the new pipe 27 is carried in by the positioning device 20. FIG. 10A shows a state in which the new pipe 27 is suspended in the excavation groove 141 by the carriage 113, and a laser beam is emitted. FIG. 10B shows the state of the truck 1
13 starts the descending of the new pipe 27, and the first target 3
FIG. 10 shows a state in which No. 1 is positioned with respect to the laser beam.
(3) shows a state in which the second target 34 is positioned on the laser beam by lowering the one end 32 side of the new pipe 27 in the pipe axis direction, and FIG. 10 (4) moves the new pipe 27 to the existing pipe 21 side. The pulling cylinder 10 of the second perfect circular ring 42
6a to 106c show a state where the first perfect circle ring 41 is drawn.

First, in step s1, the work of positioning the new pipe 27 is started, and both ends 2 of the new pipe 27 in the pipe axis direction are started.
8 and 32 are beveled by a beveling device. For example, in the case of performing electron beam welding, an I-groove is formed, and the second perfect circle ring 42 and the first perfect circle ring 87 form a perfect circle. Has been corrected. A groove is already formed at one end 22 in the pipe axis direction of the existing pipe 21 at the time of the previous welding, and is corrected to a perfect circle by the first perfect circle ring 41.

In this state, in step s2, the hook pieces 116, 1 hanging the new pipe 27 from the carriage 113 are set.
17, one end 22 of the existing pipe 21 in the pipe axis direction.
As shown in FIG. 10A, the other end 28 of the existing pipe 21 in the tube axis direction where the second perfect circle ring 42 is attached is moved in the tube axis direction. It is arranged below one end 32. In step s3,
The laser beam generating means 26 oscillates a laser beam in the visible light wavelength band, and the operator of the carriage 113 can visually recognize the laser beam. Based on this laser beam, the current position of the new pipe 27 is determined. Clearly grasp the distance to descend from, and use that distance as a guide to step s
At 4, the new pipe 27 is lowered, and the position of the new pipe 27 is adjusted so that the transmission section 29 is irradiated with the laser beam.

Next, in step s5, as shown in FIG. 10 (2), it is determined whether the laser beam has been positioned so as to transmit the laser beam through the transmitting portion 29 of the first target 31, and the positioning is performed. If not, the flow returns to step s4 again, and the respective winding means 137a and 137b and the respective lateral movement cylinders 147a and 147b are operated.
Adjust the position of the new pipe 27. In step s5, the new pipe 2 is located at a position where the laser beam is transmitted through the transmission section 29.
When 7 is arranged, the descending operation is stopped in step s6.

In this way, while maintaining the state in which the laser beam is transmitted through the transmission section 29 of the first target 31,
Moving to step s7, as shown in FIG.
The one end portion 32 of the new pipe 27 in the tube axis direction is lowered to a position where the light receiving portion 33 of the second target 34 is irradiated with the laser beam, and the lateral movement cylinders 147a and 147 are moved.
By operating b, it is also displaced in the left-right direction perpendicular to the paper surface of FIG. 10 (3). The movement of the unit 32 is stopped. Step s8
If the laser beam does not coincide with the light receiving unit 33,
Returning to step s7, the one end portion 32 of the new pipe 27 in the pipe axis direction is moved and adjusted, and the positioning operation is continued so that the light receiving section 33 is irradiated with the laser beam.

Thus, the laser beam generating means 26
The laser beam emitted from the first target 31 passes through the transmission part 29 of the first target 31 and the light receiving part 3 of the second target 34
In step s10, each of the pulling cylinders 106a to 106c provided on the second perfect circular ring 42 is irradiated.
As a result, the first perfect ring 42 is pulled as shown in FIG.

A series of operations shown in FIGS. 10 (1) to 10 (4) described above reproduce the predetermined groove accuracy at a material storage place or a factory at a pipeline laying site. That is, the new pipe 27 is fixed to the existing pipe 21 such that the groove accuracy between the existing pipe 21 and the new pipe 27 is, for example, 0.2 mm or less in the route gap G1 in step s11. Thus, the new pipe 27 is positioned with respect to the existing pipe 21 with a predetermined groove accuracy, and in step s12, the butted portions 38 of the pipes 21 and 27 are welded and connected to each other.

The electron beam welding is performed by using the pipes 21 and
7 is completed as described above, the electron beam welding apparatus already housed in the existing pipe 21 by the previous welding is moved to a position between the pipes 21 and 27, and the , 27 and the seal ring 43 and the inner space between the inner peripheral surfaces of the tubes 21 and 27 and the electron beam welding apparatus, for example, 5 × 10 ⁻² Torr. After reducing the pressure to about 30 kV to 200 kV,
A kV electron beam is irradiated over the entire circumference to form a butt welding joint, and the new pipe 27 is connected to the existing pipe 21.

The laser beam oscillator 25 provided on the existing pipe 21 and the two ends 2 in the axial direction of the new pipe 27 are thus provided.
The new pipe 27 can be positioned with respect to the existing pipe 21 using the two targets 31 and 34 provided on the pipes 8 and 32.
Checking the irradiation state of the laser beam to the new pipe 27
May be adjusted, as compared with the case of using a device that does not have a configuration for positioning, such as a bolt insertion hole of a jig for roundness correction, as in the above-described conventional technique, in an unnatural posture. In addition, it is not necessary to perform a checking operation for positioning from a plurality of different locations, so that the amount of work such as movement of an operator is reduced, and the new pipe 27 is replaced with the existing pipe 2.
It is possible to perform high-precision positioning in a short period of time without requiring time and effort for one, and the efficiency of the positioning operation is improved.

Since the laser beam generated from the laser beam oscillator 25 is a laser beam in the visible wavelength band, the laser beam is emitted to each of the targets 31 and 34 even in a dark situation such as cloudy or sunset. Is continuously displayed, and when the irradiation position is desired, it can be easily and clearly recognized, thereby preventing erroneous recognition.

Further, by looking at the target plates 81 and 91 of the targets 31 and 34, the eccentricity of the irradiation position of the laser beam with respect to the transmission section 29 and the light receiving section 33 can be recognized. Direction other end 2
It is possible to simultaneously grasp the amount of movement of the new pipe 27 necessary for positioning the tube 8 coaxially with the one end 22 of the existing pipe 21 in the pipe axis direction. Therefore, the operator only has to move the new pipe 27 in a direction in which the irradiation position of the laser beam to each of the targets 31 and 34 approaches the transmitting part 29 and the light receiving part 33, and the efficiency of the positioning operation can be significantly improved. .

As another embodiment of the present invention, the light receiving section 33 may be realized by a photoelectric conversion element such as a charge-coupled device (abbreviated as CCD) for electrically detecting the laser beam.

[0070]

According to the first aspect of the present invention, the new pipe is connected to the existing pipe by using the laser beam generating means provided on the existing pipe and the two targets provided at both ends in the axial direction of the new pipe. Can be positioned with respect to
The operator may adjust the position of the new pipe while checking the irradiation state of the laser beam to each target, and as in the above-described conventional technique, for positioning the bolt insertion hole of the jig for roundness correction. Compared to using a device that does not have the configuration described above, it is not necessary to perform a confirmation operation for positioning in an unnatural posture and from a plurality of different locations,
Therefore, the amount of work such as movement of the worker is small,
The new pipe can be positioned with high accuracy in a short time with respect to the existing pipe without any trouble, and the efficiency of the positioning operation is improved.

Since the laser beam generated by the laser beam generating means is a laser beam in the visible wavelength band, the irradiation position of the laser beam on each target can be adjusted even in dark conditions such as cloudy or sunset. Are displayed continuously, and when the irradiation position is desired, the irradiation position can be easily and clearly recognized, and erroneous recognition is prevented.

Further, since the eccentricity of the irradiation position of the laser beam with respect to the transmission part and the light receiving part of each target can be recognized, the movement of the new pipe necessary for coaxially positioning the new pipe with respect to the existing pipe. The quantities can be determined simultaneously. Therefore, the operator only has to move the new pipe in a direction in which the irradiation position of the laser beam to each target approaches the transmitting part and the light receiving part, and the efficiency of the positioning operation can be remarkably improved.

According to the second aspect of the present invention, the new pipe is connected to the existing pipe by using the laser beam oscillator provided on the existing pipe and the two targets provided at both ends in the axial direction of the new pipe. Since the positioning can be performed, the operator may adjust the position of the new pipe while checking the irradiation state of the laser beam to each target, and as in the conventional technique, the bolt of the jig for roundness correction may be used. Compared to the case of using equipment that does not have a positioning mechanism such as an insertion hole, it is not necessary to perform a positioning check operation in an unnatural posture and from a plurality of different locations, and therefore, the movement of the worker The amount of work required is small, and the new pipe can be positioned with high accuracy in a short time without the need for labor on the existing pipe, and the efficiency of the positioning work is improved.

Since the laser beam generated from the laser beam oscillator is a laser beam in the visible wavelength band, the irradiation position of the laser beam on each target can be adjusted even in a dark situation such as cloudy sky or sunset. It is displayed continuously, and when the irradiation position is desired, it can be easily and clearly recognized, thereby preventing erroneous recognition.

Further, since the eccentricity of the irradiation position of the laser beam with respect to the transmission part and the light receiving part of each target can be recognized, the movement of the new pipe necessary for coaxially positioning the new pipe with respect to the existing pipe. The quantities can be determined simultaneously. Therefore, the operator only has to move the new pipe in a direction in which the irradiation position of the laser beam to each target approaches the transmitting part and the light receiving part, and the efficiency of the positioning operation can be remarkably improved.

[Brief description of the drawings]

FIG. 1 is a tube positioning device 20 according to an embodiment of the present invention.
FIG.

FIG. 2 shows a laser beam generating means 26 viewed from above in FIG.
FIG.

3 shows a laser beam generating means 26 as viewed from the left in FIG.
FIG.

FIG. 4 shows a tube 150 used for pipeline construction.

FIG. 5 is an exploded perspective view of a first perfect circle ring 41, a second perfect circle ring 42, and a seal ring 43.

FIG. 6 is a cross-sectional view perpendicular to the axis, in which a part of an existing pipe rear end side perfect circle ring 41 is cut away.

FIG. 7 is a cross-sectional view showing a state where a new pipe 27 is suspended by a cart 113.

FIG. 8 is a diagram showing a target adjustment method.

FIG. 9 is a flowchart showing a procedure of a pipe positioning method using the positioning device 20.

FIG. 10 is a simplified sectional view showing a state in which a new pipe 27 is carried in by the positioning device 20.

FIG. 11 is a side view of a state in which respective pipes 1 and 2 are butted for explaining a conventional technique.

FIG. 12 is an enlarged sectional view of section X in FIG. 11;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 20 Positioning device 21 Existing pipe 22 One end part of existing pipe 21 in the pipe axis direction 23, 35 End face 24 Optical axis 25 Laser beam oscillator 26 Laser beam generating means 27 New pipe 28 New pipe 27 The other end in the pipe axis direction 29 Transmission part 31 First target 32 One end in the pipe axis direction of new pipe 27 33 Light receiving section 34 Second target 38 Butt section 41 First true circular ring for existing pipe 42 Second perfect circular ring for new pipe 43 Seal ring 44 Optical axis adjusting jig 45 Jig for horizontal movement 81, 91 Target plate 87 First true circular ring for new pipe 100a to 100c Divided structure 106a to 106c Pulling cylinder 113 Dolly 114, 115 Rope 116, 117 Hook piece

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Taketo Yamakawa 8th Harima-machi, Harima-cho, Kako-gun, Hyogo Prefecture F-term in Harima Plant, Kawasaki Heavy Industries, Ltd. 2F065 AA20 BB08 CC00 DD06 FF23 GG06 GG21 HH04 JJ03 JJ12 JJ14 JJ26 TT02

Claims (2)

[Claims] 1. A first pipe and a second pipe to be butt-welded.
What is claimed is: 1. A tube positioning device for positioning a relative position of a tube, comprising: a laser beam in a visible wavelength band, which is provided at one end of the first tube in the tube axis direction and perpendicular to the end surface of the first tube in the tube axis direction. A laser beam generating means, which is provided at the other end of the second tube in the tube axis direction opposite to the one end of the first tube in the tube axis direction, and has a transmitting portion through which the laser beam can pass. A tube positioning device, comprising: a first target; and a second target provided at one end of the second tube in the tube axis direction and having a light receiving unit to which the laser beam is irradiated. 2. A first pipe and a second pipe to be butt-welded.
A tube positioning method for positioning a relative position of a tube, comprising: a laser beam oscillator provided at one end of the first tube in the tube axis direction, perpendicular to an end surface of the first tube in the tube axis direction.
A laser beam in a visible wavelength band is generated, and the laser beam passes through a transmission portion of a first target provided at the other end of the second tube in the tube axis direction opposite to one end of the first tube in the tube axis direction. As described above, the other end of the second tube in the tube axis direction is moved, and the laser beam transmitted through the transmission portion of the first target is transmitted to the light receiving portion of the second target provided at one end of the second tube in the tube axis direction. Moving the one end side of the second tube in the tube axis direction so as to irradiate the second tube.