JPH0464834B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for attaching and detaching bolts, and more particularly to a device for attaching and detaching stud bolts attached to a nuclear reactor pressure vessel.

The reactor pressure vessel is constructed so that the pressure vessel body and the upper mirror, which is a sealed head placed on the pressure vessel body, are connected by stud bolts, so that the entire pressure vessel is hermetically sealed.

In nuclear reactors, it is necessary to periodically (about once a year) remove the upper mirror of the pressure vessel to confirm safety and replace fuel rods, but in this case, dozens of bolts attached to the flange of the pressure vessel must be removed entirely. In the past, bolts were removed manually, but these bolts were, for example,
Because it is a large device measuring 150 mm, 1800 mm long, and weighing about 250 kg, it takes a lot of effort and time to attach and detach it.

For this reason, a method has been proposed and implemented in which a stand is formed on the upper mirror to suspend the stud tensioner, and the stud tensioner is used to attach and detach bolts.

FIG. 1 shows how to install a conventional stud tensioner. The stud tensioner 5 is attached to a lifting arm 4 via a joint 10, and this lifting arm is attached to a station 3 that moves on an annular guide. By moving the station 3, the stud tensioner 5 is moved to a predetermined bolt, and the arm 4 is raised and lowered to mount the stud tensioner 5. In this case, a joint part 10' such as a chain is interposed between the stud tensioner 5 and the arm 4, so that when installing the stud tensioner, the worker manually guides the stud tensioner and aligns it. I have to. This is due to the fact that the stud bolts 8 installed upright on the flange 9 are not necessarily positioned in the vertical direction, and the stud tensioner needs to be installed in accordance with the position of the bolts, for reasons that will be described later.
However, since this work is carried out in a highly radioactive area, workers are at risk of being exposed to radiation, and it is impossible to work for long periods of time, resulting in low work efficiency. In addition, as shown in FIG. 1B, the stroke sensor 14 is connected to the stud tensioner 5.
There is also a device in which a stud tensioner 5 is attached to facilitate alignment, but since the stud tensioner 5 itself oscillates, alignment accuracy is low and it is not very effective.

For this reason, it may be possible to eliminate the joint part 10' to significantly reduce the swinging of the stud tensioner 5, but as mentioned above, the bolt is not necessarily located in the vertical direction, so when installing the tensioner or When rotating, stress is applied to the stud tensioner and stud bolt, which may cause damage. Note that the reference numeral 12 in the figure is a nut screwed onto the stud bolt 8.

FIGS. 2 and 3 specifically illustrate this problem. To remove the stud bolt 8, first attach the stud tensioner 5 to the stud bolt 8, connect the engaging body 5a to the stud bolt, and rotate the stud bolt to attach the stud bolt 8 to the flange on the pressure vessel body side. Release the screwing with 20. Next, the hydraulic system 13
Pull out the bolt using the stud tensioner body as support. In this case, as each bolt is pulled out, the tightening force in the circumferential direction of the flange 9 becomes uneven, and the pressure vessel body flange 20
Then, the upper mirror flange 9 is no longer parallel, and the upper mirror is tilted. For example, in FIG. 3, by removing the bolt located on the opposite side of the illustrated bolt 8 with the upper mirror in between, the upper mirror 9 will be tilted by the tightening force of the illustrated bolt 8 using the seat surface 21 as a fulcrum. Put it away. However, since a certain gap is formed between the bolt itself and the flange 9, it remains positioned substantially vertically. In order to rotate and pull out the bolt, it is necessary that the stud tensioner 5 and the axis of the bolt 8 coincide,
If the stud tensioner 5 is arranged so that its axes coincide with each other, a gap W is formed between the stud tensioner 5 and the flange 9, making it impossible to rotate or pull out the bolt. A similar problem occurs when attaching bolts.

The purpose of this problem is to eliminate the above-mentioned problems, and the object is to provide a device that can easily perform center alignment with the bolt and can reliably rotate and pull out the bolt even if the flange is tilted.

In short, this invention involves attaching and detaching a bolt cleaning device, a stud tensioner, and a nut attachment/detachment device to and from the stud bolts, which are suspended from a station that moves along the arrangement direction of the stud bolts on the upper lid of the pressure vessel, and by remote control. In a device for attaching and detaching nuts from stud bolts, a part of the shaft that suspends and lowers the bolt cleaning device, stud tensioner, and nut attaching/detaching device is a universal joint, and this universal joint attachment part is included and the shaft is mutually connected. An inner cylinder and an outer cylinder are provided that are in contact and slide in the axial direction. When the stud tensioner descends and engages the stud bolt, the inner cylinder and the outer cylinder disengage, and when the stud tensioner rises, they engage. This bolt attachment/detachment device is characterized in that a locking device is formed with the stud tensioner to prevent the stud tensioner from swinging when aligning the stud tensioner and the stud bolt.

Examples of the present invention will be described below.

FIG. 4 shows the entire apparatus, in which a pedestal 2 having a flange 9 and a corresponding annular guide 2a is attached to the pressure vessel upper mirror 1. 3 is a station that moves along this guide,
A stud tensioner 5 is suspended from this station with a lifting arm 4. Note that it is effective to attach a bolt cleaning device 6, a nut detaching device 7, etc. outside the stud tensioner.

FIG. 5 shows details of the support part of the stud tensioner 5. A universal joint (hereinafter simply referred to as "joint") 10 is installed between the lifting arm 4 and the stud tensioner 5, so that the rotational force on the lifting arm side is transmitted regardless of the inclination of the stud tensioner 5. It is configured. Next 1
1a is the outer cylinder attached to the station 3 side, 11
b is an inner cylinder attached to the stud tensioner 5 side and configured to be slidable with respect to the outer cylinder 11a;
Since the inner cylinder 11b is inserted into the outer cylinder, the two become an integral cylinder and act as a locking device to prevent the joint 10 from swinging.

Next, the operation of this device will be explained.

In FIGS. 6 and 7, the stud tensioner 5 is moved onto a predetermined stud bolt by the station 3, while the lifting arm 4 is pulled upward. For this reason, the outer cylinder 11a and the inner cylinder 11b of the locking device are integrated to prevent the stud tensioner 5 from swinging about the universal joint 10 (see FIG. 6A).
Next, once the stud tensioner is placed on a predetermined bolt, it is lowered and aligned using the stroke sensor 14 as shown in FIG. At this stage, the inner cylinder and outer cylinder are still engaged, so there is no rocking and alignment can be performed with high precision. Once alignment is completed, the stud tensioner 5 is placed on the flange 9, and in this state the locking device is disengaged.

FIG. 7 shows the mounting condition when the flange 9 is inclined at an angle α with respect to the horizontal plane 21. Even in this case, the universal joint can transmit rotational force well to the stud bolt, so the bolt Bolts can be attached and detached without damaging them.

In addition, the above-mentioned equipment has accurate alignment and bolts can be easily attached and removed regardless of whether the flange is tilted, so there is no need for a worker to be near the equipment, and everything can be controlled remotely. .

By carrying out this invention, the stud bolt can be attached and detached safely and reliably without damaging the bolt.

[Brief explanation of drawings]

Figures 1A and B are side views showing a conventional stud tensioner in a suspended state, Figure 2 is a cross-sectional view of the stud tensioner, Figure 3 is a partial cross-sectional view of the stud tensioner and flange, and Figure 4. 5 is a side view showing the entire device according to the present invention, FIG. 5 is a sectional view of the universal joint portion, and FIGS. 6A to C
is a side view showing the operating state of the device according to the present invention,
FIG. 7 is a side view of a stud tensioner showing how the device according to the invention is attached to an inclined flange. 3...Station, 4...Elevating arm, 5
... Stud tensioner, 10... Universal joint, 11a... Outer cylinder, 11b... Inner cylinder.

Claims (1)

[Claims] 1 Attach and detach the bolt cleaning device, stud tensioner, nut attaching/detaching device, etc. to the stud bolts, which are suspended from a station that moves along the arrangement direction of the stud bolts on the upper lid of the pressure vessel.
In a device for attaching and detaching nuts from stud bolts by remote control, part of the shaft from which the bolt cleaning device, stud tensioner, and nut attaching/detaching device are suspended and raised and lowered is a universal joint, and this conniversal joint attachment part is used as a universal joint. An inner cylinder and an outer cylinder are provided which are enclosed and in contact with each other and are slidably displaced in the axial direction, and when the stud tensioner descends and engages with the stud bolt, the engagement between the inner cylinder and the outer cylinder is released.
A bolt attaching/detaching device characterized in that the stud tensioner is engaged to form a locking device when the stud tensioner is raised, and is configured to prevent the stud tensioner from swinging when aligning the stud tensioner and the stud bolt.