JPS6351746B2 - - 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 nuclear reactors and fuel replacement, the upper mirror must be removed.
When the upper mirror is removed, the well provided at the top of the pressure vessel is filled with water to prevent radioactive contamination. 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 conventional stud bolt cleaning method. 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. The purpose of wearing plastic bags is to prevent the scattering of radioactive dust generated during cleaning work, but
The effect of preventing scattering is not necessarily sufficient;
There is a high risk that workers will be exposed to radiation inside their bodies if they inhale it, and it is difficult to collect the dust. Additionally, as more than 100 stud bolts are attached to each 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) 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, a plurality of air intake ports 3c are provided in the inner cylinder, 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, and more specifically, a device that enhances the bolt cleaning effect and allows the cleaning device to be easily attached and detached. Our goal is to provide the following.

In short, this invention has a structure in which a support brush that rotates around the bolt is attached, and this support has a split structure so that the bolt cleaning device can be easily attached to and detached from the bolt even if a highly rigid wire brush is used. It is.

The present invention solves the above problems and has the following features.

(1) When the handle 7 is lifted up, the wire brush moves away from the stud and is displaced toward the inner wall of the cleaning device main body 11, so that the stud will not be damaged when pulled out. The stud will not be damaged even when it is then mounted over the adjacent stud. The force with which the brush is pressed against the stud is constant and corresponds to the weight of the rotating part.

(2) The brush length is a fraction of the support. Sequentially spiral around multiple supports,
The entire surface of the mounting stud can be brushed by rotating it.

(3) By using the lower roller wheel 14 and the engagement hole, no twisting occurs when the support is rotated.

(4) In the present invention, air is sucked through the dust suction passage 20 at the bottom of the device, so there is no accumulation of dust.

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. However, if a highly rigid wire brush or the like is used, the bolt cleaning device can be attached to the stud bolt 3. In this case, the brush 12 gets caught on the thread of the threaded portion 3a, making the device difficult to operate and also damaging the brush. For this reason, the support 13 to which the brush 12 is attached is made into a split structure (see Figure 3), and when the cleaning device main body is attached to the stud bolt, each support is moved to the inner wall side of the main body 11 (in the X direction in the figure) and A gap is formed between 12 and the threaded portion 3a, or they are in slight contact with each other.

Next, to explain the moving state of the support in detail, when attaching the cleaning device main body 11 to the stud bolt, the device main body is suspended by the handle 7 provided at the top of the device main body and inserted into the threaded part 3a. However, by suspending the main body of the device, the handle 7 is pulled upward as shown in the left half of FIG.
By this pulling up, the guide 9 comes off from the engagement hole 10a due to the weight of the support 13, and the sliding plate 8 attached to the upper part slides down the slope part 10b of the rotary disk 10, and each support 13 moves in the X direction. . When the installation of the device main body 11 is completed, the handle 7 and the rotary disk 10 that engages with it are lowered, and the engagement hole 10 is lowered.
The guide 9 is inserted again into the inside of a, and each support 13
moves in the Y direction, and the brush 12 strongly contacts the threaded portion 3a with a force corresponding to its own weight. Note that code 15
is a lower guide attached to the lower end of support 13,
Reference numeral 14 designates rolling wheels having engagement holes corresponding to the number of supports having trapezoidal slopes as shown, which engage with the lower guide 15.

The bolt cleaning device is attached to the stud bolt in the manner described above, and then the rotating shaft of the motor (not shown) is inserted into the engagement groove 21 formed at the upper end of the device. 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. The removed dust is sucked and removed through the dust suction passage 20.

By carrying out this invention, even if a highly rigid brush is attached, the cleaning device can be easily attached to and detached from the bolt without causing unnecessary damage to the bolt, and the cleaning effect of the bolt can be enhanced and the operability of the device can be improved.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the stud bolt insertion part of the reactor pressure vessel, Figure 2 is a sectional view of the bolt cleaning device,
FIG. 3 is a sectional view taken along line AA in FIG. 3... Stud bolt, 7... Handle, 9... Guide,
10...Rotary disk, 12...Brush, 13...Support.

Claims (1)

[Claims] 1. For cleaning large stud bolts, a guide 9 is installed in the cylindrical cleaning device main body 11, the lower end of which is engaged with the engagement hole of the rolling wheel 14 which is coaxial with the main body 11, and the guide 9 is connected to the upper end. A plurality of supports 13 are inserted through the engagement holes 10a of a rotary disk 10 which is rotationally driven, and are positioned at intervals in a coaxial cylindrical surface, and a brush 12 is fixedly connected to each support 13, and the guide 9 is The upper end is fixedly connected to a sliding plate 8 which is fixedly connected to the rotary disk 10, and the engagement hole of the wheel, the engagement hole of the rotary disk, and the guide each have a trapezoidal conical slope, so that it can be lifted or suspended. A split brass type bolt cleaning device characterized in that a handle 7 for displacing the support 13 in the radial direction of the device is connected to the cleaning device main body so as to be movable in the axial direction.