JPS6351750B2 - - 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 that tighten 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.

Figure 1 shows a method for cleaning stud bolts. The stud bolt 3 is inserted through the flange 1a of the upper mirror 1 and is threadedly engaged with the flange 2a of the pressure vessel main body 2, and the nut (not shown) is threadedly engaged with the threaded portion 3a of the bolt 3, which is the threaded portion of the nut. . When cleaning the bolt, first, a plastic bag 4 is placed over the threaded portion 3a, and the cleaning is performed manually by placing the hand in the plastic bag 4 and using 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. Additionally, as more than 100 stud bolts are attached to a single pressure vessel, manual cleaning takes a long time and increases 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) The wire brush is always pressed against the stud using a coil spring 48 shown in FIG.

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 purpose of this invention is to eliminate the above-mentioned problems and provide a device that automatically cleans bolts.More specifically, it is an object of the present invention to provide a device for automatically cleaning bolts. To provide a bolt cleaning device configured to smoothly perform bolt cleaning.

In short, this invention arranges a roller at the bottom of a support, and the roller is configured to smoothly rotate via a bearing on a guide rail formed in a skirt portion, and in some cases, a stopper is attached to the roller. It is configured to prevent the support from twisting when attached.

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

In FIG. 2, the 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. Reference numeral 13 denotes a support disposed in an annular space formed between the cylindrical portion 11a and the threaded portion 3a of the cleaning device main body 11, and 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 this guide 9 is connected to the engagement hole 10 of the rotary disk 10.
It is inserted through a. On the other hand, a lower guide 15 is attached to the lower end of the support 13.
It is configured to be inserted into an engagement hole 14a formed in 4. Reference numeral 22 denotes a lower skirt portion forming a part of the cleaning device main body 11, and is connected to the cylindrical portion 11a by screws 23. Lower skirt 22
A guide rail 24 is formed in an annular shape on the inner peripheral surface of the roller, and the rollers 14 are rotatably mounted on the guide rail 24 via bearings 25. Next, reference numeral 26 is a stopper attached to the wheel 14, which prevents the guide 15 from being twisted due to the sliding movement of the brush 12, as shown at 13' in FIG.

By the above method, each support 13 is configured such that its upper end is supported by the rotary disk 10 and its lower end is supported by the wheel 14, and rotates about the threaded portion 3a.

In the bolt cleaning device described above, when the device is attached to the bolt, the brush 12 gets caught on the threaded portion 3a, making the attachment work difficult. Make it easier.

First, when attaching the device body to the stud bolt, suspend the device body using the handle 7 and tighten the threaded portion 3a.
By suspending the main body of the device, the handle 7 is pulled upward as shown in the left half of FIG. 2. As a result, the sliding plate 8 attached to the upper part of the guide 9 slides down the slope portion 10b of the rotary disk 10, and the support 13 moves in the X direction.
Thereby, even if the brush 3 is hard, the entire body can be easily inserted into the threaded portion 3a.
When the installation of the device main body 11 is completed, the handle 7 descends due to its own weight, and as a result, the support 13 approaches the Y direction, that is, the threaded portion 3a, as shown in the right half of FIG.

Once the installation of the device is completed, insert a motor (not shown) into the engagement groove 21 formed in the center of the rotary disk 10.
Insert the rotating shaft. As a result, the support 13 is rotated by the rotational force of the motor, and the brush 12 removes rust, dust, etc. from the threaded portion 3a. In this case, each support 13 engages with a roller 14, and the roller 14 smoothly rotates on the guide rail 24 by the bearing 25, so that the support 13 rotates around the threaded portion 3a without wobbling or the like. Rotates well. Further, by providing a stopper 26 on the wheel 14, twisting of the support 13 can be prevented.

By carrying out this invention, the support to which the brush is attached can be rotated smoothly and the support will not be twisted, so that the cleaning efficiency of the bolt can be improved.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a stud bolt insertion passage 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 a sectional view taken along line AA in FIG. 3... Stud bolt, 11... Bolt cleaning device main body, 12... Brush, 13... Support, 14... Rolling wheel, 22... Lower skirt, 24... Guide rail,
25...bearing, 26...stopper.

Claims (1)

[Claims] 1 The lower end of the cylindrical device body has a dust suction passage, the lower end is located in the engagement hole of the rolling wheel provided at the bottom of the device body, and the engagement hole of the rotary disk through which the guide connected to the upper end is rotationally driven. In an apparatus for cleaning a large stud, which has a plurality of brushed supports inserted therethrough, the brushed supports are displaced toward the wall inside the apparatus body when the apparatus is suspended by a handle, and the brushed supports are inserted into the lower skirt 22 of the apparatus body. A guide rail 24 is formed on the peripheral wall, a bearing 25 is provided between the guide rail and the roller 14, and a stopper 26 for preventing twisting of the support is provided on the roller. Bolt cleaning device.