JP2549504Y2 - Stud bolt elongation measuring device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stud bolt elongation measuring device for measuring the elongation of a stud bolt at the time of fastening a nut of a stud bolt on a body flange of a reactor pressure vessel.

[0002]

2. Description of the Related Art A large number of stud bolts for attaching and detaching a lid at the top of a pressure vessel are arranged on a body flange of a reactor pressure vessel installed in a nuclear power plant or the like. Sometimes the lid is opened and after the inspection,
The lid is attached.

[0003] When attaching the lid, each stud bolt is fastened with a nut. At this time, the elongation of each stud bolt is measured so that the surface pressure of the sealing surface between the body flange and the lid becomes a predetermined value. You.

FIG. 4 shows the upper part of the reactor pressure vessel. As shown, a large number of stud bolts 4 for attaching and detaching the lid 3 are provided on the body flange 2 of the reactor pressure vessel 1. The stud bolts 4 are arranged and planted, and the upper ends of the stud bolts 4 project upward from the attached lid 3, and nuts 5 are screwed to the projections.

A sealing member 6 is interposed between the body flange 2 and the lid 3, and when the nut 5 is fastened, the sealing member 6 has a predetermined value to maintain the airtightness of the sealing member 6. The nut 5 is fastened so as to apply the surface pressure described above, and the elongation of the stud bolt 4 is measured to measure the degree of fastening.

A conventional device for measuring the extension of a stud bolt, as shown in FIG. 4, inserts a measuring rod 8 into a measuring hole 7 formed along the axis of the stud bolt 4 in advance. A dial gauge 9 for measuring the positional displacement of the measuring rod 8 is seated on the top surface 4a of the stud bolt 4, and when the nut 5 is fastened, the positional displacement of the measuring rod 8 with respect to the top surface 4a is determined. The elongation of the stud bolt 4 was measured with the dial gauge 9.

[0007]

However, in the above-mentioned apparatus, a stand (not shown) for horizontally supporting the dial gauge 9 is provided, and the stand is fixed on the body flange 2 or the like to dial. The gauge 9 is seated on the top surface 4a of the stud bolt 4, but if the mounting accuracy (vertical accuracy) of the stud bolt 4 is poor, the reference surface of the dial gauge 9 is brought into close contact with the top surface 4a of the stud bolt 4. This may not be possible, and if measurement is performed in this state, accurate measurement cannot be performed, and there is a problem that measurement accuracy varies.

Further, since the dial gauge 9 is used for detecting the measured value, the measuring operation must be performed manually, and the stud bolts 4 are measured one by one.
There is also a problem that the work takes a long time and the worker is exposed.

Accordingly, an object of the present invention is to provide a stud bolt elongation measuring device capable of automatically and accurately measuring the elongation of a stud bolt in order to solve the above problems.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is to seat a stud bolt on the top surface of a body flange of a reactor pressure vessel. In a stud bolt elongation measuring device for measuring the elongation of the stud bolt from the displacement of the top surface of the bolt with respect to a measuring rod previously inserted in the stud bolt, a support frame is fixedly provided near the stud bolt, and the support frame is always downwardly directed to the support frame. And a horizontal shaft extending so as to intersect with the axis of the stud bolt is connected to the vertical member, and the axial position of the stud bolt is connected to the horizontal shaft. In addition to the self-aligning bearing, the centering bearing is mounted so that it can swing around the shaft center and the lower end is seated on the top surface of the stud bolt. That the reference frame provided, in which the displacement amount is constituted by providing a displacement sensor for measuring in contact with the top surface of the measuring rod in the reference frame.

[0011]

According to the above construction, the support frame is fixed near the stud bolt to be measured, and the reference frame is pressed and seated on the top surface of the stud bolt, and then inserted in advance into the measurement hole of the stud bolt. The displacement sensor may be brought into contact with the top surface of the measuring rod to measure the displacement amount.

At this time, the reference frame is automatically swung around the axis of the stud bolt by the aligning bearing and is accurately seated on the top surface of the stud bolt. Can be accurately seated at a predetermined position, and the measurement accuracy can be improved.

Further, since the displacement sensor is used for detecting the measured value, the measured value can be transmitted electrically, and automation of the entire apparatus can be achieved.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings.

1 to 3 show an embodiment of a stud bolt elongation measuring device according to the present invention.

In this embodiment, the upper portion of the reactor pressure vessel is the same as that shown in FIG. 4 of the conventional example, and the reference numerals of the configuration are the same and the detailed description is omitted.

As shown in FIGS. 1 to 3, the stud bolt 4 has an upper end protruding upward from the lid 3, and a nut 5 for fastening the stud bolt 4 is screwed onto the protruding portion. A measurement hole 7 is formed in the axis Y of the stud bolt 4 along the axial direction. A measurement rod 8 inserted in advance is provided in the measurement hole 7, and the displacement of the measurement rod 8 is determined. A stud bolt elongation measuring device 10 for measuring and elongating the stud bolt 4 is provided on a measuring device supporting mechanism (not shown) which is automatically controlled by remote control so as to be able to move up and down.

In this embodiment, the stud bolt elongation measuring device 10 is provided with a support frame 11 fixed near the stud bolt 4 as shown in the figure.

The support frame 11 is formed so as to surround the outer periphery of the stud bolt 4 in a substantially semicircular shape, and has a lower end seated on the upper surface of the nut 5 screwed to the stud bolt 4. This seat frame 12
The vertical shaft 13 is supported by a vertical shaft support member 14 provided on the seating frame 12 so that the vertical shaft 13 stands upright.

An elevating member 15 constantly urged downward is provided on the vertical shaft 13 so as to be able to move up and down. Between the upper surface of the elevating member 15 and the top of the vertical shaft 13 inserted through the elevating member 15. A pressing spring 16 for pressing the lifting member 14 downward is provided.

The elevating member 14 has a stud bolt 4
Horizontal axis 1 extending horizontally to intersect with the axis Y of
The horizontal shaft 17 is provided with a self-aligning bearing 1 that self-aligns in accordance with the position of the axis Y of the stud bolt 4.
8 is mounted, and its centering bearing 18 is used to
A reference frame 19 is provided so as to be able to swing around and the lower end is seated on the top surface 4 a of the stud bolt 4.

As shown in FIG. 1, the horizontal shaft 17 has a horizontal axis X and an axis Y of the stud bolt 4 at its tip.
A convex spherical shaft 20 whose outer periphery is formed in a convex spherical shape with respect to an intersection O with the center is provided, and the outer periphery of the convex spherical shaft 20 is provided on the inner surface of the above-mentioned centering bearing 18, and on the inner circumferential surface thereof. A concave spherical bearing 21 into which the convex spherical shaft 20 is inserted is provided. The concave spherical bearing 21 has a convex spherical shaft 2 around the intersection O.
0 is rotatable about the axis Y of the stud bolt 4 and the axis X of the horizontal axis.

The reference frame 19 extends downward from the centering bearing 18 as shown in the figure, and has a lower end provided with a reference plate 2 seated on the top surface 4a of the stud bolt 4.
2 are provided. As shown in FIG. 3, the reference plate 22 is formed in a disk shape slightly smaller than the outer diameter of the top surface 4a of the stud bolt 4, is mounted horizontally on the reference frame 19, and has a lower surface. A recess 23 is formed so as to straddle the measurement hole 7 of the stud bolt 4.

The reference frame 19 is provided with a displacement sensor 24 which abuts on the top surface of the measuring rod 8 and measures the amount of displacement. The displacement sensor 24 is provided with an extendable movable contact 25 abutting on the top surface of the measuring rod 8, and the displacement sensor 24 is configured such that the vertical axis of the movable contact 25 is the axis of the stud bolt 4. It is attached to the reference frame 19 so as to be located at Y.

In the figure, reference numeral 26 denotes an insertion hole formed in the reference plate 22 for passing the contact 25 of the displacement sensor 24, and reference numeral 27 denotes a power supply cable for supplying power to the displacement sensor 24.

Next, when measuring the elongation of the stud bolt 4 for explaining the operation of the above embodiment, first, the stud bolt elongation measuring device 10 is remotely and automatically controlled by a measuring device supporting mechanism (not shown). The support frame 11 is fixed by being seated on the nut 5 on which the seat frame 12 is screwed so that the axis of the contact 25 of the displacement sensor 24 is located at the axis Y of the stud bolt 4 to be measured.

At this time, the reference plate 22 of the reference frame 19
Is seated on the top surface 4a of the stud bolt 4 by the pressing force of the pressing spring 13, and the contact 2
5 is inserted into the measurement hole 7 of the stud bolt 4.

In this state, the displacement sensor 24 is
And the lower surface thereof is brought into contact with the top surface of the measuring rod 8 in the measuring hole 7 to measure the displacement amount of the measuring rod 8 with respect to the standard top surface 4a of the stud bolt 4 and to conclude the measured value. The amount of extension of the stud bolt 4 is detected based on the comparison with the previous measurement value, and the amount of extension is transmitted by electric transmission.

When the reference frame 19 is seated, the centering bearing 18 automatically swings around the axis Y and the horizontal axis X to accurately seat the reference plate 22 on the top surface 4a.

Thus, even if the mounting accuracy of the stud bolt 4 is poor and the top surface 4a is inclined,
Since the reference frame 19 can be automatically and accurately seated on the top surface 4a, the elongation of the stud bolt 4 can be measured accurately, and the measurement accuracy can be improved.

Further, since the measurement is performed by the displacement sensor 24, automation of the measurement can be achieved, and exposure of the worker can be prevented.

[0032]

According to the present invention, the reference frame can be automatically and accurately seated on the top surface of the stud bolt, so that accurate measurement can be performed and measurement accuracy can be improved. In addition, since measurement is performed by the displacement sensor, automation of the measurement can be achieved, and exposure of the worker can be prevented.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view illustrating an embodiment of a stud bolt elongation measuring device of the present invention.

FIG. 2 is a front view of FIG.

FIG. 3 is a plan view of FIG. 1;

FIG. 4 is a schematic sectional view illustrating a conventional stud bolt elongation measuring device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 reactor pressure vessel 2 trunk flange 4 stud bolt 4 a top surface 5 nut 7 measuring hole 8 measuring rod 10 stud bolt elongation measuring device 11 support frame 15 elevating member 17 horizontal shaft 18 aligning bearing 19 reference frame 24 displacement sensor X horizontal Shaft center Y Stud bolt center

Claims (1)

(57) [Scope of request for utility model registration] 1. A stud bolt which is seated on a top surface of a stud bolt of a body flange of a reactor pressure vessel and, when a nut is fastened, elongation of the stud bolt from displacement of the top surface of the bolt relative to a measuring rod previously inserted into a measurement hole of the stud bolt. In a stud bolt elongation measuring apparatus for measuring the stud bolt, a supporting frame is fixedly provided in the vicinity of the stud bolt, a vertically movable vertically movable member is provided on the supporting frame, and the vertically movable member is A horizontal shaft extended so as to intersect with the axis of the stud bolt is connected, and a self-aligning bearing is mounted on the horizontal shaft corresponding to the axial position of the stud bolt. In the above, a reference frame is provided so as to be swingable around the axis, and the lower end is seated on the top surface of the stud bolt, and the reference frame is provided on the top surface of the measuring rod. A stud bolt elongation measuring device comprising a displacement sensor for measuring a displacement amount of the stud bolt.