JP2003043179A - Centering device and centering method of cylindrical subject - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device capable of quickly indexing a passing core of a subject. SOLUTION: This centering device is provided with first and second centering mechanisms 8 and 9 positioned at an interval on a cylindrical inside surface of a nozzle 2, and respectively extensible in the radial direction, a concentric shaft 10 for coaxially supporting these first and second centering mechanisms 8 and 9, handles 14a and 14b for extending the first and second centering mechanism 8 and 9 in the radial direction by rotation from an external part of the nozzle 2, and a ruled line writing needle 16 installed on the concentric shaft 10, and marking a work ruled line c for regulating a surface at a right angle to the axis of the nozzle 2 on the outer periphery of the nozzle 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centering device for indexing the axial center of the inner surface of a cylindrical object and a centering method for centering a cylindrical object by this centering device. Regarding

[0002]

2. Description of the Related Art A nozzle for connecting a large pressure vessel such as a reactor pressure vessel to a pipe is cut by cutting the tip of the nozzle when replacing the pipe. The dimensional tolerance of the welding groove for attaching the pipe to be replaced is required to be a right angle to the core (for example, 1 mm to the core) as in the existing nozzle. In the case of a reactor pressure vessel, the scoring work for enabling the groove is a work under a high radiation dose, so the nozzle core is indexed in a short time and the squareness to this core is obtained. It becomes necessary to write a cutting line for processing the actual product.

An example of the prior art in which the nozzle connecting the reactor high pressure vessel and the pipe is cut to replace the pipe will be described below with reference to FIGS. 3 to 7. FIG. 3 is a view for explaining the configuration of a reactor pressure vessel and piping connected by a nozzle of this vessel, and FIG. 4 is a vertical cross-section for explaining the squareness tolerance of the welding groove surface after cutting the nozzle. FIG. 5, FIG. 5 is a vertical cross-sectional view showing a machining scribe line perpendicular to the nozzle axis, FIG. 6 is a view for explaining a state when a disc for centering a nozzle in a conventional technique is set, and FIG. FIG. 5 is a front view of FIG. 4.

As shown in FIG. 3, a pressure vessel 1 such as a nuclear reactor and a pipe 3 are connected by a nozzle 2. on the other hand,
In machining the tip of the nozzle 2, as shown in FIG. 4, the perpendicularity to the axis of the weld groove surface is indexed to obtain the cutting line XX.
Need to disconnect from. In factory production, a single nozzle is placed on a machine such as a lathe, and while rotating, the concentricity is obtained from the centering reference points a and b in FIG.
Since the processing line c that is at a right angle is marked, it is not necessary to find the core of the nozzle again even after the nozzle is attached to the body of the pressure vessel 1.

However, since the existing products are not premised on modification and no permanent machining line, that is, a reference line, is provided at the tip of the nozzle, it is necessary to index the squareness of the nozzle shaft ship by another method. Became. As this means, as shown in FIGS. 6 and 7, a disc 4 in which concentric circles are pre-scored at the reference positions of the centering base points a ′ and b ′ of the nozzle 2 is shown.
Insert the core, find the machining line c core while adjusting the dimension l between the concentric circle reference line and the nozzle inner wall with the adjusting screw 5, locate one end of the compass 6 on this core, and place the other end of the compass 6 on the nozzle 2 The method of writing the processing line c on the outer peripheral surface was adopted.

[0006]

However, in the above-mentioned method, in order to adjust the center position of the centering disc 4,
Since the operator must directly insert the arm and operate the adjusting screw 5, the inner diameter of the nozzle (about 500 mm or more) necessary for the operation is required, which is sufficient for the centering adjustment due to the structure. It is difficult to approach and it becomes a bottleneck. Furthermore, in the case of a reactor pressure vessel and the like, under a high radiation dose, it is often impossible to secure a time for completing the adjustment. In this case, although a combination of optical measuring instruments is conceivable, it may be impossible to carry it out due to radiation contamination, which is a cost problem.

The present invention has been made in view of the above circumstances of the prior art, and an object thereof is to be able to approach a narrow space without using expensive measuring equipment such as optical measuring equipment, and An object of the present invention is to provide an apparatus capable of quickly indexing the wick of a subject while reducing the exposure dose even in the work in the high radiation region. And for other purposes,
It is possible to provide a method for centering a cylindrical object by using a device having such a function.

[0008]

In order to achieve the above object, the first means is that the first means has elastic members which are located on the inner surface of a cylindrical subject with a space and are extendable in the radial direction. First and second centering means, supporting means for supporting the first and second centering means on the same axis, and rotation of the first and second centering means from outside the subject. A rotation operation member that expands and contracts the elastic member in the radial direction is provided, and the core position of the subject is indexed from the center position of the supporting means.

In this case, one end of each of the first and second centering means is rotatably connected, and the other end of each of the first and second centering means has the elastic member supported on the support shaft side so as to be separated from each other by rotation. Then, the contact adjustment to the inner peripheral surface of the subject on the one end side is performed by extending the other end side of each elastic member. Further, it is preferable that the elastic members are provided at three positions in the circumferential direction with respect to the support shaft. Further, it is possible to provide a ruler which is attached to the supporting means and is provided on the outer periphery of the subject to mark a surface defining a plane perpendicular to the axis of the subject.

The second means is a cylindrical centering method for a subject, which is located on the inner surface of the subject at a distance and is extendable in the radial direction, and on a support shaft on the same core. First and second having elastic members supported by
The centering means of each of the first and second centering means are disposed by the supporting means for supporting the first and second centering means, respectively. Extending the elastic member by a rotation operating member so as to contact the inner peripheral surface, and using a ruler attached to the support shaft, a mark defining a surface perpendicular to the core axis of the object is provided on the outer periphery of the object. The feature is that centering of the subject is performed by indexing a surface perpendicular to the axis of the subject by attaching.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 is a sectional view showing a state in which a centering device according to an embodiment of the present invention is set in a nozzle, and FIG. 2 is a right side view of FIG.

In FIG. 1, reference numeral 2 denotes a nozzle attached to a pressure vessel (not shown) installed on site, and the nozzle tip is cut for pipe replacement. Reference numeral 7 denotes an entire centering device according to an embodiment of the present invention. The centering device 7 includes first and second centering devices arranged on the same shaft 10 at intervals in the axial direction. The centering mechanisms 8 and 9 are provided. The first centering mechanism 8 has a shaft 10
, A pantograph mechanism 11a having three elastic members arranged at equal intervals in the circumferential direction, a ball screw 12a provided so as to open the pantograph mechanism 11a in the axial direction of the shaft 10, and the ball screw. Rotation transmission gear 13a meshing with 12a, and this rotation transmission gear 13a
Handle 1 located outside nozzle 2 for rotating
4a are provided. The pantograph mechanism 11a is
By rotating the handle 14a, the rotation transmission gear 1
3a rotates, and the pantograph mechanism 1 depends on the rotation direction.
The leg (corresponding to the elastic member) opens and closes 1a. When the leg is opened, the distance from the axis of the shaft 10 to the tip of the leg is shortened, and when the leg is closed, the distance from the axis of the shaft 10 to the tip of the leg is lengthened. As a result, it has a stretching function. The second centering mechanism 9 also has the same configuration as the first centering mechanism 8, and detailed description thereof will be omitted. In order to distinguish from the configuration of the first centering mechanism 8, the second centering mechanism 9
The reference number indicating the constituent requirement of is attached with “b”.

Numeral 15 is a ruler which is detachably provided at right angles to the concentric shaft 10. A ruler needle 16 is attached to the tip end bent in a substantially L shape so as to write a machining line c on the outer peripheral surface of the nozzle 2. Has been.

The operation and operation of the centering device thus constructed will be described below.

The approach to the inner surface of the nozzle 2 is made by the existing nozzle 2
After cutting the tip of the, it is limited to the outer surface of the pressure vessel, but has a small diameter (diameter about 300 mm) and a deep depth (about 600 mm).
mm), the work for indexing the inner diameter core is almost impossible. Therefore, the centering device 7 sets the positions of the first centering mechanism 8 and the second centering mechanism 9 in advance in the axial dimension corresponding to the centering base points a and b, and fixes them. Next, the centering device 7 is inserted from the tip end side of the nozzle 2, that is, from the small edge side, aligned with the centering reference point a on the inner side of the nozzle 2 and the centering reference point b on the small edge side of the nozzle 2, and each handle 14
a and 14b are rotated, and the ball screws 12a and 12b are rotated via the rotation transmission gears 13a and 13b. The ball screws 12a and 12b are right-handed screws and left-handed screws, and the pantograph mechanisms 11a and 11b rotate in one direction.
Of the pantograph mechanisms 11a and 11b move in the direction in which the legs on the side of the concentric shaft 10 come together.
It projects in the radial direction of 0.

By repeating this operation for the first and second centering mechanisms 8 and 9, the supporting legs of the pantograph mechanisms 11a and 11b contact the inner surface of the nozzle 2 at three points. With such a three-point support method, each support leg of the pantograph mechanisms 11a and 11b expands, comes into contact with the inner wall of the nozzle 2, and if there is no play and is fixed, the center of the shaft 10 supporting both support legs is reached. The line will form the core of the nozzle 2. In this way, approach the narrow space,
It is possible to easily and quickly index the core through the inner diameter of the nozzle 2.

At this point, the ruler 15 attached to the ruler 15 is rotated by rotating the ruler 15 attached to the end surface of the shaft machined at right angles to the axis of the centering device 7.
Thus, it is possible to secure a processing line c perpendicular to the central axis of the nozzle on the outer peripheral surface of the nozzle 2. In this way, the center line of the nozzle 2 can be quickly obtained by all axial driving operations and operations, and the accessibility of the narrow space can be secured and the exposure dose in the case of a reactor high pressure vessel can be reduced.

[0018]

As described above, according to the present invention, the apparatus is adjusted in advance, that is, the centering means is adjusted in the radial direction in accordance with the axial centering base point position of the subject and the inner diameter of the subject. Since it can be carried out from the outside, if it is used, for example, to replace the piping of the reactor high pressure vessel, the working time in a radiation exposure environment can be shortened and the exposure dose can be reduced.

Further, according to the present invention, since the first and second centering means are constituted by pantographs, all the centering operations of the subject are performed by the transmission of the force in the axial direction to open the legs. Can be run.

Further, according to the present invention, since three pantograph means are provided, it is possible to accurately grasp the inner peripheral surface of the subject and enable accurate centering.

Further, according to the present invention, a mark defining the surface perpendicular to the core axis can be attached to the outer periphery of the subject by a ruler, and thereby accurate centering can be performed.

Further, according to the present invention, the first and second
Centering means are arranged on the inner surface of the subject at a distance, and the respective tip portions of the first and second centering means are brought into contact with the inner peripheral surface of the subject by the rotating operation member. By extending it and attaching a mark on the outer periphery of the subject to the outer periphery of the subject to define a surface that is perpendicular to the axis of the subject, it is possible to easily determine a surface that is perpendicular to the axis of the subject. The sample can be easily centered.

[Brief description of drawings]

FIG. 1 is a side view showing a state in which a part of a centering device according to an embodiment of the present invention is set in a nozzle and is cut away.

FIG. 2 is a front view of FIG.

FIG. 3 is a diagram for explaining a configuration of a reactor pressure vessel and piping connected by a nozzle of this vessel.

FIG. 4 is a vertical cross-sectional view for explaining the squareness tolerance of the weld groove surface after cutting the nozzle.

FIG. 5 is a vertical cross-sectional view showing a machining marking line perpendicular to the nozzle axis.

FIG. 6 is a diagram for explaining a case where a nozzle centering disc according to a conventional technique is set.

FIG. 7 is a front view of FIG.

[Explanation of symbols]

2 nozzles 7 Centering device 8 First centering mechanism 9 Second centering mechanism 10 concentric axes 11a, 11b Pantograph mechanism 12a, 12b Ball screw 13a, 13b Rotation transmission gear 14a, 14b handle 15 Ruler 16 scribed needle a, b Centering point c Processing ruled line

Claims (5)

[Claims] 1. A first and a second centering means, which are spaced apart from each other on the inner surface of a cylindrical object and have elastic members that can extend in the radial direction, respectively, and the first and second cores. Supporting means for supporting the centering means on the same axis, and a rotation operation member for expanding and contracting the elastic members of the first and second centering means in the radial direction by rotation from the outside of the subject, A cylindrical centering device for a subject, wherein the centering position of the subject is indexed from the center position of the supporting means. 2. The first and second centering means respectively have the elastic members, one end side of which is rotatably connected, and the other end side of which is supported on the support shaft side so as to be separated from each other by rotation. The cylindrical centering device for a subject according to claim 1, wherein contact adjustment to the inner peripheral surface of the subject on the one end side is performed by extending the other end side of each elastic member. 3. The cylindrical centering device for a subject according to claim 2, wherein the expanding and contracting members are provided at three locations in the circumferential direction with respect to the support shaft. 4. A ruler, which is attached to the supporting means and is provided on the outer circumference of the subject for marking a mark that defines a surface perpendicular to the axis of the subject. 1. A centering device for a cylindrical object according to any one of 1. 5. A method of centering a cylindrical object, wherein the object is located at a distance from the inner surface of the object, is radially expandable, and is supported on a support shaft on the same core. First and second centering means having elastic members are arranged, and by the supporting means for supporting the first and second centering means, the tip end portions of the respective elastic members of the first and second centering means are arranged. Each of the elastic members is extended by a rotation operation member so as to come into contact with the inner peripheral surface of the subject, and the core axis of the subject is attached to the outer periphery of the subject by using a ruler attached to the support shaft. A cylindrical object centering method, characterized in that the surface perpendicular to the axis of the object is indexed by marking the surface with a mark that defines a surface perpendicular to the object.