JPS6361076B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a large bolt cleaning device, and more particularly to a bolt cleaning device suitable for cleaning stud bolts fastened to an upper mirror, which is the upper cover of a nuclear reactor pressure vessel.

When performing periodic inspections of the reactor and replacing fuel, the upper mirror must be removed. When the upper mirror is removed, water is filled in the well provided at the top of the pressure vessel to prevent radioactive contamination. will be held. In this case, the stud bolts that attach the upper mirror to the pressure vessel body also become soaked in water, causing rust, and the bolts must be cleaned before and after removing and attaching the nuts.

Fig. 1 shows a method for cleaning stud bolts, in which the stud bolt 3 is inserted through the flange 1a of the upper mirror 1 and is screwed into the flange 2a of the pressure vessel main body 2, and a nut (not shown) is inserted into the bolt 3. It is threadedly engaged with a threaded portion 3a which is a mating portion. When cleaning a bolt, first, a plastic bag 4 is placed over the threaded portion 3a, and the cleaning is carried out manually by a worker who puts his/her hand into the plastic bag 4 and uses a wire brush. Wearing plastic bags is intended to prevent the scattering of radioactive dust generated during cleaning work, but the effect of preventing scattering is not necessarily sufficient, and there is a high risk that workers will be exposed to radiation internally if they inhale it. Moreover, it is difficult to collect the dust. In addition, as more than 100 Studvolds are attached to a single pressure vessel, manual cleaning requires a long period of time, increasing the risk of exposure to radiation.

A device for cleaning large stud bolts was devised in Utility Model Application No. 58283/1983. In the device according to this invention, the wire brush is rotated in contact with the bolt screw as in the present application, but there are the following problems.

(1) As shown in FIG. 7, the wire brush is always pressed against the stud using a coil spring 48. This forces the device to be pushed into the stud in opposing contact with the stud, which can cause cracking and damage to the stud in large studs made of special materials that are sensitive to scratches.

(2) Air is taken in from the middle of the outer cylinder of the device, and air is extracted from the middle of the outer cylinder of the device. In addition, the inner cylinder is provided with a plurality of air intake ports 3c, and the resistance to air flow is large. Dust collects at the bottom of the device.

(3) The brush 4 has approximately the same length as the outer cylinder 2. To replace the brush, remove bolts 11 and 12.
It is necessary to take out a heavy device including a rotating body from the outer cylinder, and it takes time and effort to replace the brushes.

The object of this invention is the patent application filed on the same day as the present application (Japanese Patent Application No. 55-182120 (Japanese Unexamined Patent Publication No. 57-107273))
The present invention relates to an improvement of the brush support for the apparatus. More specifically, the present invention provides a bolt cleaning device configured to prevent a brush rotating around a bolt from wobbling and twisting.

In short, this invention attaches a support that has a brush and rotates around a bolt to a rolling wheel using two or more guides, and prevents the support from twisting or rattling with respect to the rolling wheel. It is constructed to prevent twisting.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 2, a cylindrical cleaning device main body 11 is arranged with respect to the threaded portion 3a of the stud bolt 3 protruding from the flange 1a of the upper mirror so that its center axis is located on the center axis of the threaded portion 3a. There is. Reference numeral 13 denotes a support disposed in an annular space formed between the cleaning device main body 11 and the threaded portion 3a,
A brush 12 is attached to the threaded portion 3a side.
A guide 9 is fixed to the upper end of the support 13, and the guide 9 is inserted into the engagement hole 10a of the rotary disk 10. As will be described later, this guide 9 is rotated by a motor around the threaded portion 3a, but due to the resistance of the brush 12 that is in contact with the threads and valleys of the threaded portion 3a, the side of the guide 9 in the direction of rotation is rotated. It behaves as if it were caught on the threaded portion 3a side. Figure 3 shows the structure of the supports configured to prevent this entanglement.
Two lower guides 15 are attached to the lower end of the wheel 3, and these two guides 15 are formed on the wheel 14 and inserted into the engagement hole 14a. As a result, the support 13 can be attached to the wheel 14 without twisting, and can sufficiently resist the resistance of the brush 12.

Next, the operation of the support when the cleaning device main body is attached to the threaded portion 3a of the stud bolt 3 will be specifically explained. First, when attaching the cleaning device body to the stud bolt, the device body is suspended by the handle 7 provided on the top of the device body and inserted into the threaded portion 3a. 7 is pulled up in the X' direction as shown in the left half of FIG. Note that reference numeral 6 is a stopper that holds the handle 7 from being pulled up to a certain limit. As a result, the rotary disk 10 that engages with the handle 7 also rises in the X' direction. 8 is a sliding plate attached to the guide 9,
A slope 10b whose end is formed on the side wall of the rotary disk 10
is in contact with. As the rotary disk 10 rises, the sliding plate 8 slides down the slope relatively due to the weight of the guide 9, and the engagement hole 10a between the guide 9 and the rotary disk 10 is closed.
Release the engagement state with. Along with this relative lowering of the sliding plate 8, the entire support 13 rises in the X direction,
At the same time that the engagement between the guides 9 and the engagement holes 10a is released, the engagement between the lower guides 15, two of which are attached to the bottom of each guide 9, and the wheels 14 is also released, and the support 13 is moved in the X direction. Move to. As a result, a gap is formed between the brush 12 and the threaded portion 3a, or a light contact is made between the brush 12 and the threaded portion 3a, thereby facilitating attachment of the device to the bolt.

Next, when the bolt cleaning device is attached to the threaded portion 3a, the handle 7 and the rotary disk 10 are moved by their own weight.
Descend in the Y′ direction. Engagement hole contact portion of guide 9;
Since the lower guide 15 has a substantially conical contact surface, as the rotary disk 10 descends, the guides 9 and 15 gradually engage with the engagement hole 10a and the engagement hole 14a of the roller 14. and support 13 to Y
direction, and finally engage completely as shown in the right half of FIG.

Once the bolt cleaning device has been installed as described above, the rotating shaft of the motor (not shown) is inserted into the engagement groove 21 formed in the upper part of the cleaning device main body. As a result, the rotational force of the motor is transmitted to the support 13 via the rotary disk 10 and the guide 9.
Rust, dust, etc. on the threaded portion 3a are removed by a brush provided on the threaded portion 3a. In this case, the brush 12 can be cleaned well if it is made of a material with relatively high rigidity, but each support 13 has two lower guides 15 against the wheel 14 as shown in FIG. Since the support 13 is attached, the support 13 does not twist even if the resistance increases due to the highly rigid brush. 20
is a dust suction passage that suctions and removes dust generated during the bolt cleaning process.

By implementing the present invention, it is possible to prevent the support to which the brush is attached from twisting and rattling, and it is possible to effectively clean the bolt.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a stud bolt insertion portion of a reactor pressure vessel, FIG. 2 is a sectional view of a bolt cleaning device according to the present invention, and FIG. 3 is an exploded perspective view of a support. 12...Brush, 13...Support, 14...
Rolling wheel, 14a...Engagement hole, 15...Lower guide.

Claims (1)

[Claims] 1. An engagement hole of a rotary disk that has a dust suction passage at the lower end of the cylindrical device body, the lower end is located in the engagement hole of the rolling wheel provided at the bottom of the device body, and the guide connected to the upper end is rotationally driven. In an apparatus for cleaning a large stud, the lower end of the one support 13 is provided with a plurality of brushed supports through which the brushed supports are inserted, and when the apparatus is suspended by the handles of the brushed supports, the supports are displaced toward the inner wall of the apparatus main body. A cleaning device for preventing twisting of a support, characterized in that a plurality of lower guides 15 are connected to the roller, and engagement holes 14a corresponding to the plurality of lower guides are formed in the roller.