JPS6329593B2 - - 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.

During periodic inspections of the reactor and fuel replacement, the upper mirror must be removed, but in order to prevent radioactive contamination when the upper mirror is removed, the well installed at the top of the pressure vessel must be Water filling is done. 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 how to clean stud bolts. 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 the nut (not shown) is screwed into the threaded portion 3a of the bolt 3, which is the nut screwing portion. There is. 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 risk of internal radiation exposure if workers inhale it. It is expensive and it is difficult to collect 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.

An object of the present invention is to eliminate the above-mentioned problems and provide a device that automatically cleans bolts. More specifically, when a cleaning device is attached to a bolt, the bolt cleaning brush To provide a bolt cleaning device configured so that it does not get caught.

In short, this invention is configured to move the support to which the brush is attached in a direction perpendicular to the central axis of the bolt by moving the handle provided on the main body of the cleaning device up and down, thereby making it easy to attach and detach the cleaning device. be.

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

Fig. 2 shows the bolt cleaning device attached to the stud bolt 3, and the cylindrical cleaning device main body 11 is attached to the threaded portion 3a of the stud bolt 3 protruding from the flange 1a of the upper mirror. It is arranged so as to be located on the central axis of the portion 3a. 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.
The brush 12 comes into contact with the threads and valleys of the threaded portion 3a and slides on the surface of the threaded portion 3a to remove rust. For this reason, the brush 12 must be a wire brush, and the wire constituting the brush must have relatively high rigidity. 12 gets caught on the thread of the threaded portion 3a, making installation difficult and also damaging the brush. For this reason, the support 13 to which the brush 12 is attached has a separate structure, and when the cleaning device main body is attached to a stud bolt, each support is attached to the main body 11.
The brush 12 is moved toward the inner wall side (X direction in the figure) to form a gap between the brush 12 and the threaded portion 3a, or to make slight contact with the brush 12 and the threaded portion 3a.

Next, to explain the operation of the support 13 in more detail, when attaching the cleaning device body to the stud bolt, the device body is suspended by the handle 7 provided at the top of the device body and inserted into the threaded portion 3a. However, by suspending the main body of the device, the handle 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 guide 9
A sliding plate attached to the rotary plate 10 with an end thereof
It is in contact with the slope 10b formed on the side wall portion of.
As the rotary disk 10 rises, the sliding plate 8 relatively slides down this slope due to the weight of the guide 13, and the engagement between the guide 9 and the engagement hole 10a of the rotary disk 10 is released. With this relative lowering of the sliding plate 8, the entire support 13 rises in the X' direction, and at the same time the engagement between the guide 9 and the engagement hole 10a is released, and at the same time the engagement between the lower guide 15 and the roller 14 is released. has also been lifted,
And the support 13 moves in the X direction.

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

Once the bolt cleaning device has been installed using the above method, the engagement groove 2 formed on the top of the cleaning device body
Insert the rotating shaft of a motor (not shown) into 1 (see Fig. 3). As a result, the rotational force of the motor is transmitted to the support 13 via the rotary disk 10 and the guide 9, and the brush provided on the support 13 removes rust, dust, etc. from the threaded portion 3a. The removed dust is removed by suction from a dust suction passage 22 provided at the bottom of the main body of the apparatus.

By carrying out this invention, even if a highly rigid brush is attached, the cleaning device can be easily attached to the bolt, and the ease of handling can be improved without reducing the cleaning ability of the device.

[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 a view taken along line AA in FIG. 3... Stud bolt, 7... Handle, 8... Sliding plate, 9... Guide, 10... Turntable, 10a...
...Engagement hole, 12...Brush, 13...Support,
10b...Slope.

Claims (1)

[Claims] 1. In a device that cleans a bolt by rotating a plurality of supports to which brushes are attached, around the bolt, an inclined surface is formed on the side wall of the rotary disk, and a member that slides in contact with the inclined surface is provided. A brush moving type bolt cleaning device characterized in that each support is moved in a direction perpendicular to the center axis of the bolt through the support. 2. The member is a sliding plate that contacts and slides on the slope, and a guide that connects to this sliding plate and the support,
The brush movement according to claim 1, characterized in that the rotary disk is formed with an engagement hole that engages with the guide, and each support is moved in response to the vertical movement of the handle and the rotary disk. Type bolt cleaning device.