JPS6318905Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a vacuum tester, that is, a vacuum testing device for checking the presence or absence of welding defects at welding points of the bottom plate, side plate, annular plate, etc. of an oil storage tank, for example. .

BACKGROUND ART Conventionally, a vacuum tester has been generally used as a method of checking for welding defects in welding parts of bottom plates, side plates, annular plates, etc. in petroleum storage tanks.

The test method using a vacuum tester is a method of discovering welding defects by coating the tester with soapy water applied to the welding location and creating a vacuum inside the tester.

In other words, by applying soapy water to the welding part and creating a vacuum inside the tester that covers the welding part as described above, if there is a welding defect at the welding part, Bubbles are generated through the action of soapy water, and the presence or absence of welding defects can be accurately checked based on the presence or absence of bubbles.

However, in order to accurately check for the presence or absence of air bubbles, it is necessary to obtain a complete vacuum inside the tester. It is required that the lower end of the tester be tightly adsorbed. Conventionally, a method of attaching soft rubber to the lower end of the tester has been used to bring the lower end of the tester into close contact with the welding plate, but with this method, the vacuum pressure inside the tester As a result, the soft rubber cannot withstand the welding plate sufficiently, causing abnormal deformation of the soft rubber toward the inside of the tester, resulting in the inconvenience that a complete suction effect on the welded plate cannot be obtained.

One of the ways to solve this problem is to install a gate-shaped mounting frame facing downward along the lower edge of the tester, and fit a hard sponge body into the mounting frame. A method has been proposed to prevent abnormal deformation of the soft sponge body by fixing a soft sponge body to the lower end of the body and coating the exposed surface of the soft sponge body with a thin film made of synthetic resin ( Jitsukō 48-43426
issue).

However, in the above method, when a constant vacuum pressure is applied, the entire vacuum pressure is applied to the soft sponge body before the hard sponge body deforms. While the body deforms and the thin synthetic resin film peels off from the same soft sponge body after repeated use,
If even higher vacuum pressure is applied, the hard sponge body will deform and the lower end of the mounting frame will come into contact with the synthetic resin thin film, damaging the synthetic resin thin film and causing damage to the synthetic resin thin film. The problem is that the soft sponge body protected by the thin film is deformed abnormally.

The present invention is an attempt to improve the situation in view of the above-mentioned circumstances, and makes it possible to obtain a state in which the adsorbent rubber layer smoothly compresses and deforms under vacuum pressure without causing abnormal deformation. There are several issues that need to be resolved. That is, in the present invention, the adsorption rubber layer is divided into three layers by interposing the hard rubber layer between the soft rubber layers, and a constant pressure is applied to the upper soft rubber layer via the mounting frame. The compressive deformation is controlled against the vacuum pressure above, while the lower soft rubber layer is brought into pressure contact through the hard rubber layer, resulting in abnormal deformation of both the upper and lower soft rubber layers. It is made so that it can be prevented,
The feature is that it is possible to obtain a vacuum tester that has an excellent adsorption effect on welded plates.

That is, in the present invention, a gate-shaped mounting frame is provided downward along the lower edge of the main case, which has a peephole at the top and is formed into an arbitrary shape, and a soft rubber layer is attached to the mounting frame toward the lower edge. A part of the soft rubber layer is fitted so that it protrudes from the mounting frame, while a hard rubber layer is fixed to the lower end of the soft rubber layer with a slight clearance between it and the mounting frame. The gist of this is that it is constructed so that a soft rubber layer is provided thereon.

Hereinafter, specific embodiments of the present invention will be described with reference to the illustrative drawings.

1 to 4 are drawings relating to a vacuum tester for flat surfaces, and in the drawings, reference numeral 1 indicates a main body case. The main body case 1 has openings at the top and bottom, and four side walls 2, 2', 3,
3' is formed into a rectangular frame shape, and a vacuum chamber 15 is provided within the main body case 1. The top of the main body case 1 has side walls 2, 2', 3,
A flange 4 extending horizontally outward from the upper edge of 3' is provided, and a transparent plate 6 made of glass or acrylic resin is mounted on the flange 4 via a sealing rubber 5.
It is made so that it is placed. On the other hand, a cover 7 is formed with an opening 7' of an appropriate size, and the cover 7 is covered on the transparent plate 6 via a sealing rubber 5'.
By fixing it on the collar 4 through..., a peephole 9 is formed in the same part.

Further, a groove opening downward is provided at the bottom of the main body case 1, and a mounting frame 10 having a gate-shaped cross section is provided along the lower edge of each side wall 2, 2', 3, 3'. Therefore, the inner and outer plates 11 and 11' forming the mounting frame 10 have an inner plate 11 and an outer plate 11'.
The length dimensions are slightly different from each other so that the lengths of the parts 1 are slightly longer.

A soft rubber layer 12, which is made of foamed rubber and is formed to be flexible and deformable, is fitted into the groove of the mounting frame 10. Soft rubber layer 1
2 is provided so that its lower end protrudes slightly downward from the lower end edge of the inner plate 11 constituting the mounting frame 10, and a hard rubber layer 13 is fixed to the lower end of the soft rubber layer 12. . Therefore, the hard rubber layer 13 is formed wider than the width of the lower end of the soft rubber layer 12, and there is a slight clearance a between the upper surface of the hard rubber layer 13 and the lower edge of the inner plate 11. Form as it is formed. It is preferable that the clearance a is within the range of 1 mm to 10 mm. At the lower end of the hard rubber layer 13, a soft rubber layer 14 for suction is fixed, which is made of cellular rubber and is flexible and deformable, similar to the soft rubber layer 12.

Further, an ejector 16 is fixed to the side wall 2 of the main body case 1 in communication with the vacuum chamber 15, and an air supply pipe 17 communicating with an air source (not shown) is connected to the ejector 16. A vacuum gauge 18 is provided on the other side wall 2' facing away from the vacuum chamber 15 in communication with the vacuum chamber 15.

FIG. 5 to FIG. 8 are drawings regarding the corner vacuum tester, in which the mounting frame 10, which is fixed to the lower end of the main body case 1, is provided on both side walls 2 and 2' along the longitudinal direction. The frame is number 8
As shown in the figure, the soft rubber layer 14 attached to the side walls 2 and 2' extends in the direction of 45 degrees to the bottom plate and side plate of the tank. Alternatively, the lower edges of both side walls 3 and 3' along the width direction of the main body case 1 are set at right angles to each other so that they can be adsorbed to a welded plate such as an annular plate with a phase angle of 90 degrees. By protruding in a chevron shape at an angle of The soft rubber layer 14 is provided so as to be able to be adsorbed in an L-shape along both the bottom plate, side plate, or welded plate such as an annular plate of the tank.

Furthermore, an ejector 16 for connecting an air supply pipe 17 is fixed to one side wall 3 of both side walls 3 and 3' along the width direction of the main body case 1, while a vacuum gauge is attached to the other side wall 3'. 18 to be fixed.

In both of the embodiments described above, an ejector method is used as a means to obtain a vacuum state within the vacuum chamber 15, but the means for obtaining a vacuum state within the vacuum chamber 15 is limited to the ejector method described above. It is also possible to obtain a vacuum state using a vacuum pump system, as shown in Figures 9 and 10.
The choice is free. Furthermore, in both of the above embodiments, the inner plate 1 constituting the mounting frame 10
1 is formed to be elongated with respect to the outer plate 11',
It is also possible to form both side plates 11, 11' to have the same length dimension.

Next, the operation will be explained with reference to the first embodiment shown in FIGS. 1 to 4.

After applying soapy water to the welded parts of the tank, etc., with the vacuum tester according to the present invention placed on the surface to which the soapy water has been applied, air is supplied from the air source into the air supply pipe 17. By feeding the air, a negative pressure state is created in the vacuum chamber 15 through the feeding action of the air, and a vacuum state is finally obtained.

Then, a negative pressure state is generated in the vacuum chamber 15, and in the process of obtaining a vacuum state, the soft rubber layer 12 and the hard rubber layer 13, which are fitted into the grooves of the mounting frame 10, are fixed to the lower ends. The soft rubber layer 14 where
They are compressed through the negative pressure action within the vacuum chamber 15, respectively.

However, in the case of the soft rubber layer 12, the vacuum chamber 1
By being compressed through the negative pressure action within the hard rubber layer 13, an airtight state is obtained in the same area.
The mounting frame 10 had a clearance a of approximately
The lower edge of the inner plate 11 is connected to the soft rubber layer 1.
Through the compression action of 2, a state of being pressed against the upper surface of the hard rubber layer 13 is obtained. After the lower edge of the inner plate 11 is pressed to the upper surface of the hard rubber layer 13 in this way, the soft rubber layer 1
2 can be prevented from further compressive deformation, and the inner plate 11 of the mounting frame 10 is directly pressed against the hard rubber layer 13 to prevent further negative pressure action within the vacuum chamber 15. Hard rubber layer 13
This results in a pressurizing effect on the area.
Therefore, in the soft rubber layer 12, there is no abnormal deformation as seen in conventional structures, and a completely airtight state can be obtained in the same area.

On the other hand, in the soft rubber layer 14 fixed to the lower end of the hard rubber layer 13, pressure is applied almost uniformly to the entire surface of the soft rubber layer 14 through the hard rubber layer 13. Even in such cases, abnormal deformation can be prevented, and a state can be obtained in which the welded plate is tightly adsorbed to the bottom plate, side plate, or annular plate of the tank.

In this way, the soft rubber layer 14 is tightly adsorbed to the bottom plate, side plate, or welded plate such as the annular plate of the tank, thereby making it possible to obtain a complete vacuum inside the vacuum chamber 15. be. Furthermore, if there is a welding defect at a welding point when a complete vacuum state is obtained in the vacuum chamber 15, air bubbles will be generated through the action of soapy water. It is possible to discover the location of a welding defect through the occurrence of this phenomenon.

The present invention is constructed as described above.
As described above, the gate-shaped mounting frame 10 is provided facing downward along the lower edge of the main body case 1, and the soft rubber layer 12 is fitted into the mounting frame 10 so that a portion of the soft rubber layer 12 near the lower end protrudes from the mounting frame. On the other hand, a hard rubber layer 13 is fixed to the lower end of the soft rubber layer 12 with a slight clearance a between it and the mounting frame 10, and a soft rubber layer is attached to the lower end of the hard rubber layer 13. 14, the mounting frame 10
It has become possible to prevent abnormal deformation of the soft rubber layer 12 by this action, and abnormal deformation of the soft rubber layer 14 by the hard rubber layer 13. That is, in response to vacuum pressure, the soft rubber layer 12 is gradually compressed and deformed by the clearance a, and when a certain level of vacuum pressure is applied, the lower edge of the mounting frame 10 and the hard rubber layer 13
While preventing abnormal deformation of the soft rubber layer 12 through contact with the soft rubber layer 12, the entire surface of the soft rubber layer 14 is compressed and deformed by applying pressure substantially uniformly through the hard rubber layer 13, In addition to being able to prevent abnormal deformation of the soft rubber layer 14, compressive deformation does not occur only in the soft material when a constant vacuum pressure is applied, unlike in the past, and both soft rubber layers 14
2, 14 and the hard rubber layer 13 can be smoothly compressed and deformed. As a result, we were able to significantly improve the suction effect of the tester on the welded plate.

In addition, in the present invention, both the upper and lower soft rubber layers 12,
Since the adsorption rubber layer is divided into three layers with the hard rubber layer 13 interposed between the adsorption rubber layers 14 and 14, there is no need to replace the entire adsorption rubber layer when it wears out. Only the soft rubber layer 14 needs to be replaced, and the replacement can be done easily and inexpensively, and the economical effect in this respect is extremely large.

[Brief explanation of the drawing]

Fig. 1 is an overall perspective view of the vacuum tester for flat surfaces, Fig. 2 is a plan view thereof, Fig. 3 is a sectional view taken along line A-A, Fig. 4 is a sectional view taken along line B-B, and Fig. 5 is for corner use. An overall perspective view of the vacuum tester, FIG. 6 is a plan view, FIG. 7 is a sectional view taken along the line C-C, and FIG. 8 is a D-
The sectional view taken along the line D, and FIGS. 9 and 10 are perspective views of the entire vacuum pump type vacuum tester. 1... Main body case, 2, 2'... Side wall, 3,
3'...Side wall, 4...Brim, 5, 5'...Seal rubber, 6...Transparent plate, 7...Cover, 7'...Opening, 8...Tightening bolt, 9...Peephole, 10
...Mounting frame, 11...Inner plate, 11'...Outer plate, 12...Soft rubber layer, 13...Hard rubber layer,
14... Soft rubber layer, 15... Vacuum chamber, 16...
Ejector, 17... Air supply pipe, 18... Vacuum gauge, 19... Compressor, 20... Suction pipe, a... Clearance.

Claims (1)

[Scope of utility model registration request] A gate-shaped mounting frame is provided downward along the lower edge of the main case, which has a peephole at the top and is formed into an arbitrary shape, and an adsorption rubber layer is fitted into the mounting frame. A soft rubber layer is fitted onto the mounting frame so that a part of it near the lower end protrudes from the mounting frame, while a hard rubber layer is fitted onto the lower end of the soft rubber layer with a slight clearance between it and the mounting frame. A vacuum tester characterized in that the absorbent rubber layer has a three-layer structure by fixing the layers and providing a soft rubber layer at the lower end of the hard rubber layer.