JPS6133984A - Inlet fan fitting structure of fixed tubular article - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inlet fan mounting structure for a fixed tubular object that can automatically open and close an inlet fan for opening and closing the inlet of a guide pipe for inspection in a nuclear power plant, for example. .

[Conventional technology]

In order to guarantee the integrity of the piping in the next system of a nuclear power plant, periodic inspection is necessary.

However, since the sub-system piping is irradiated with strong radiation, its inspection is carried out exclusively using unmanned inspection equipment.

Since the inspection target of this type of primary system piping is its welded joint, conventionally a guide tube is attached to the welded section of the piping to be inspected in advance, and an inspection tool is inserted into the inside of this guide tube. Inspections are being conducted.

The guide tube of this type of guide tube system requires an inlet fan for introducing the above-mentioned inspection tools, and this inlet fan is kept closed during periods when inspections are not being performed, for example, when the atomic couplant is in operation. It is necessary. That is, by connecting an inlet fan that opens and closes the entrance of the guide tube, it prevents dust from entering the guide tube, and at the same time provides a sealing function and prevents convection to ensure its insulation performance. is necessary.

However, in the conventionally used inlet fan device, a motor 2 is provided at the inlet fan of the guide tube 1, as shown in FIG. 4, for example.
A cover (entrance door) 3 is attached to this motor 2 and the inlet fan is electrically driven to open and close, or the inlet fan 4 is moved inside the guide tube 1 by the force of inserting the inspection tool as shown in FIG. There are things that can be pushed out.

[Problem that the invention seeks to solve]

However, in the case shown in FIG.
The drive mechanism for the lid 3 including the lid 3 becomes complicated and large. Moreover,
Since the motor 2 is provided in a radiation atmosphere, there are disadvantages such as undesirability. Furthermore, since such a drive device is installed in a radiation environment, there are problems such as extremely difficult maintenance and repair work in the event of a failure. Furthermore, although the structure shown in FIG. 5 has features such as a simple structure, when the entrance door 4 is opened to the inside of the guide tube 1, dust accumulated on the entrance door 4 is removed. It gets inside the guide tube 1. As a result, there is a problem that the purpose of providing the entrance door 4 is lost. Moreover, there are other problems such as the entrance door 4, which opens inward, getting in the way of inserting testing tools.

In order to solve these problems, the present invention effectively prevents dust from entering fixed tubular objects such as guide tubes, and also opens and closes reliably when testing tools are inserted, etc. To provide a highly practical entrance door mounting structure for a fixed tubular article that does not interfere with loading, has a simple configuration, and eliminates the need for maintenance.

[Means for solving problems]

The present invention provides a ball screw shaft mounted on the outer surface of a fixed tubular object such as a guide tube via a bracket, such that the tip extending in the axial direction of the fixed tubular object projects beyond the inlet opening of the fixed tubular object. and the ball screw shaft is biased toward its distal end by a compression spring, and a ball nut supporting an entrance door for opening and closing the entrance opening of the fixed tubular object is screwed onto the ball screw shaft. and the ball nut is rotated in response to the movement of the ball screw shaft in the axial direction by pressing the tip of the ball screw shaft, so that the entrance door opens and closes the entrance opening of the fixed tubular object. This is what I did.

〔Effect of the invention〕

Thus, according to the present invention, the ball nut is rotated by moving the ball screw shaft forward and backward by pressing the tip of the ball screw shaft, and the entrance door supported by the ball nut is rotated to open the entrance opening of the guide pipe or the like. Since it has a simple structure of opening and closing, it can be constructed compactly and requires almost no maintenance. Moreover, since it is only necessary to press the tip of the ball screw shaft in response to the inserting operation of the test tool, the operation can be performed reliably and automatic opening/closing operation can be achieved. In addition, since the entrance door is rotated to the side of the entrance fan, it does not get in the way of inserting the testing tools, and dust that accumulates on the entrance door does not enter the inside of the guide tube. Effects such as not being present can be produced.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the main part of a guide pipe device incorporating an entrance door mounting structure according to an embodiment, and FIG. 2 is a diagram showing its operating state. The guide tube 11, which is a fixed tubular object, has a rectangular cross-sectional structure, and its entrance opening can be selectively opened and closed by an entrance door 12. This guide tube 11
A hollow shaft 14 is attached via a bracket 13 to the outer surface near the inlet opening of the hollow shaft 14 so as to have the same axial direction. The hollow shaft 14 rotatably supports a case 17 to which a ball nut 16 is fixed via a bearing 15. The entrance door 12 is integrally supported and fixed to this ball nut 16. As a result, the entrance door 12 is rotated about the ball nut 16 from the position where it closes the entrance fan of the guide tube 11 to the lateral position where it releases the entrance fan as shown in FIG. ing.

A ball screw shaft 18, which is inserted into the hollow shaft 14 through the case 17 and screwed into the ball nut 16, is provided so as to be movable in the axial direction.

This ball screw shaft 18 is provided so that its tip protrudes from the inlet opening of the guide tube 11, and is pressed in the axial direction by a pressing member, which will be described later. Further, the ball screw shaft 18 is biased toward its distal end by a coil spring 19 provided inside the hollow shaft 14 . The end plate 2o provided at the end of the ball screw shaft 18 defines the maximum deflection position of the ball screw shaft 18 that is biased toward the tip by the coil spring 19. The range of forward and backward movement of the ball screw shaft 18 is limited by the locking portion 18a for the coil spring 19. still.

The ball screw shaft 18 has a key 2 fitted into its slit.
1 prevents its own rotation.

In other words, the ball screw shaft 18 is biased toward the distal end of the hollow shaft 14 and prevented from rotating, so that the ball screw shaft 18 can move forward and backward in the axial direction.
is provided, and a ball nut 16 is provided to be rotatably screwed onto this ball screw shaft 18.
The inlet 12 is supported by the inlet.

On the other hand, a pressing member 23 that presses the tip of the ball screw shaft 18 in the axial direction is caused by a coil spring 24 to press the tip of the ball screw shaft 18.
It is biased to the side and stored in the case 25. The pressing member 23 is provided within the case 25 so as to be able to move forward and backward within a predetermined range in the axial direction. This case 25 is fixed via a bracket 27 to the side surface of a test tool storage body 26 into which a test tool (not shown) is introduced into the guide tube 11 from the entrance opening of the guide pipe 11. Then, in order to put the test tool into the guide tube 11, the test tool storage body 26
When the test tool storage body 26 is moved to approach the guide tube 11, the tip of the ball screw shaft 18 is pressed by the pressing member 23 immediately before the test instrument storage body 26 comes into contact with the guide tube 11.

According to the mechanism configured in this manner, when the test instrument storage body 26 is brought close to the guide tube 11, the pressing member 23 is first moved.
The ball screw shaft 18 is pressed by the coil spring 19.
Move downward in the figure while compressing.

At this time, the ball screw shaft 18 is connected to the key 21 as described above.
Since rotation is prevented by the ball nut 16, the ball nut 16 rotates as the ball screw shaft 18 moves in the axial direction. This rotation of the ball nut 16 causes the inlet 12 to rotate laterally, opening the inlet opening of the guide tube 11. Then, when the coil spring 19 reaches its compression limit due to the movement of the ball screw shaft 18 and the ball screw shaft 18 becomes unable to move, the ball screw shaft 18 presses the pressing member 23 instead. As a result, the coil spring 24 biasing the pressing member 23 is compressed, and the pressing member 23 moves upward inside the case 25. Therefore, the ball screw shaft 18 is moved to the lowest position and held, and the inlet 12 keeps the inlet of the guide tube 11 open.

While forming this state, the test tool storage body 26 continues to move and fits into the entrance of the guide tube 11. In this state, a test tool is put into the guide tube 11 from the test tool storage body 26.

On the other hand, when the test tool storage body 26 is raised and separated from the guide tube 11, the pressing member 23 is first returned to its original position under the action of the coil spring 24. However, in this state, the ball screw shaft 18 is still held at the lowest position.
Therefore, the inlet 12 is in a state where the inlet of the guide tube 11 is open. Thereafter, when the test tool storage body 26 rises sufficiently, the pressing member 23 rises accordingly, and the ball screw shaft 18 moves upward under the action of the coil spring 19. As a result, the ball nut 16 is rotated in the opposite direction, and the inlet 12 is rotated to a position where the inlet of the guide tube 11 is closed. and,
After the inlet of the guide tube 11 is closed by the inlet 12, the pressing member 23 is separated from the tip of the ball screw shaft 18.

In this way, according to the present structure, the rotation of the ball nut 16 is controlled by advancing and retreating in the axial direction due to the pressure of the ball screw shaft 18, thereby rotating the inlet 12, and the guide tube 1
1 can be effectively opened and closed. Moreover, since the inlet 12 can be rotated to the side of the guide tube 11, the connection between the test instrument storage body 26 and the guide tube 11 is not hindered.

Further, dust accumulated on the inlet 12 is not dropped into the guide tube 11. Since it is a simple configuration in which the rotation of the ball nut 16 due to the screwing of the ball screw shaft 18 and the ball nut 16 is effectively used to rotate the inlet 12, this can be realized compactly. Almost no maintenance is required. Moreover, the movement is simple and reliable operation can be expected. Therefore, there are no problems encountered with conventional devices, and its practical advantages are enormous.

Note that the present invention is not limited to the embodiments described above. For example, as shown in Figure 3, two ball screw shafts iaa
, isb are provided, and these ball screw shafts 18a, 18b
A ball nut 16a that is screwed together and rotates in opposite directions to each other.
, 16b, the pair of inlet fans 12a, 12b may be spread out on both sides. Further, the shape of the inlet fan of the guide tube is not limited to the square shape as in the embodiment, but may be circular shape or the like. Further, although the guide tube in an atomic couplant has been described here as an example, the present invention can be similarly applied to opening and closing the entrance of other tubular objects. In short, the present invention can be implemented with various modifications without departing from the gist thereof.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a schematic configuration diagram showing the structure of an embodiment of the present invention;
The figures show the working state of the structure of the embodiment, FIG. 3 shows a modified example, and FIGS. 4 and 5 show conventional examples, respectively. 11... Guide pipe, 12... Inlet fan, 13.27...
・Bracket, 14...Hollow shaft, 15...Bearing, 1
6...Ball nut, 17°25...Case, 18
... Ball screw shaft, 19.24 ... Coil spring, 2
0... End plate, 21... Key, 23...
Pressing member, 26...Testing tool storage body. Applicant Sub-Agent Patent Attorney Takehiko Suzue Figure 1 Figure 2

Claims (1)

[Claims] A ball screw shaft that is attached to the outer surface of a fixed tubular object via a bracket and has a tip extending in the axial direction of the fixed tubular object protruding beyond an inlet opening of the fixed tubular object, and this ball screw shaft. a compression spring biased toward its tip; a ball nut that is screwed onto the ball screw shaft and rotates in response to the movement of the ball screw shaft in the axial direction by pressing the tip of the ball screw shaft; An inlet fan mounting structure for a fixed tubular object, comprising an inlet fan that is supported by the ball nut and rotates together with the ball nut to open and close an inlet opening of the fixed tubular object.