JP2000131181A - Inspection method for sheet-bonding part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inspect a sheet-bonding part simply and at low cost by a method wherein a pressurized gas is blown against the boundary of the sheet bonding part, changes in the sound generated are captured, and bonding defect parts are detected. SOLUTION: While a pressurized gas (air) is being blown against a boundary 4 of a bonding part 3 of a sheet 1 to a sheet 2 from an air nozzle 5, it is moved from one end to the other end of the bonding part 3, and the bonding state for the entire length of the bonding part 3 is inspected. At this time, if there is a place in which the sheets 1, 2 are bonded insufficiently, since the pressurized gas flows to the circumference along the shape of the bonding part 3, sound which is characteristic of the state is generated. When a part which cannot be bonded or a part which is bonded insufficiently exists, since pressurized gas flows into the gas between the sheets, the flow of the gas is changed. A sound which is different from the sound generated in the normal bonding part 3 is generated. Consequently, the part in which the different sound is generated is specified as being a bonding defect part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting a joint portion of a sheet impermeable to water, such as a waterproof sheet or a water-blocking sheet, used for construction or civil engineering.

[0002]

2. Description of the Related Art A sheet made of rubber, resin, asphalt-impregnated sheet or thermoplastic elastomer is used for waterproofing a roof of a building, a waterproof sheet and a water-blocking sheet to be laid on a reservoir, a bottom of a waste disposal site, and the like. Is used. The sheet made of each material is manufactured as a sheet of a fixed width in a factory, and is joined and cut to a required size on site to be used.

[0003] Originally, for the purposes of the application, water is not allowed to leak, which means that holes in the sheet itself are not allowed at the junction than at the book. Of course, various efforts have been made so far to reduce the number of defective joints, but it is difficult to reduce the number of defective joints in the field.

Therefore, various inspection methods for joints have been proposed in order to detect the occurrence of a defect and restore the condition so that no water leaks. For example, in the simplest method, there is a method of simply visually inspecting a joint portion of a sheet.

Also, a method of applying soap water or the like to the joint, pressing the open surface of the box connected to the pump onto the joint, reducing the pressure, and visually confirming the generation of bubbles.

[0006] Two rows of adhesive parts are arranged at one joint part, and an unjoined part surrounded by the upper and lower sheets and the two rows of adhesive parts is secured as a passage. After joining is completed, there is a method of injecting compressed air into the passage and pressurizing the passage to check air leakage. As a method for checking air leakage, a method of measuring a decrease in pressure or a method of visually confirming the generation of bubbles due to application of soapy water or the like is used.

As another example, similarly to the above-mentioned pressurizing method, two rows of adhesive portions are arranged at one joint, and the pressure in the passage surrounded by the upper and lower sheets and the two rows of adhesive portions is reduced. Is measured.

[0008]

Of the above-mentioned methods, the method of visually confirming is simple in the case where there is a large joint failure at the joint that can be visually confirmed. Although it can be said to be effective, there is a problem that the possibility of overlooking the bonding failure is large.

In the method of inspecting using a box, there is a limit to the size that can be checked at a time, and the box for inspection must be moved little by little to inspect the entire area. There is a problem that it takes time.

Next, in the case of a method in which a passage is formed by previously arranging two rows of adhesive portions at the joint, and pressurized air is injected into the passage to check for air leakage, first, a passage is formed at the joint. Since it is necessary to form the structure so that it can be inspected by this method, there is a problem that it takes time to join.

Further, it is usual to adopt a method in which a hole is made in the sheet to inject the pressurized air and a needle is inserted into the passage, but the hole has to be repaired after the inspection. It can be said that it is an irrational method of perforating a sheet that is not allowed. Also,
When pressurizing the inside of the passage, if the pressure is too high, a load will be applied to the bonded part, and the adhesive strength may be weakened. There is a problem that it becomes.

In the method of depressurizing the inside of the passage with the same structure, the labor for forming and joining the passage is the same as that of the above-mentioned method. However, although the length that can be inspected at one time can be lengthened, it is necessary to use a method by pressurization in order to finally identify the portion of the bonding failure, and the inspection may be troublesome twice.

The present invention eliminates the problem of having to prepare beforehand the structure of a joint having a structure capable of inspection, out of the problems of the conventional method as described above, and furthermore, the inspection operation itself is also reduced. It is an object of the present invention to provide a method of inspecting a sheet joint that can be performed by a simpler method.

[0014]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a method for inspecting a sheet joint in which sheets used for waterproof / waterproof use are joined. And detecting a defective bonding portion by detecting a change in a sound generated by blowing a pressurized gas to the boundary of.

By adopting such a method, it is not necessary to previously form the joint portion into a specific structure when inspecting the sheet joint portion, and the inspection operation itself is a very simple operation of merely blowing gas. Since the inspection can be performed, the inspection itself can be performed more simply and with reduced cost.

In the second aspect of the present invention, the pressure of the pressurized gas to be blown is in the range of 5 to 10 kgf / cm ² , and it is possible to generate a volume sufficient to detect a change in sound.

Further, in claim 3, the angle at which the pressurized gas is blown is in the range of 10 to 60 ° with respect to the sheet.

By doing so, it is possible to reduce the pressure of the gas to be blown, and to generate a sound change that can be sufficiently detected.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a sectional view of a joint portion of a general water-impervious sheet to which the inspection method of the present invention is applied, to which the inspection method can be applied. FIG. Figure 1 where the inspection method is being implemented
FIG.

As shown in FIG. 1, the sheet joining portions to which the method of the present invention can be applied are joined to each other in a state where the sheets overlap each other, and the boundary between the joined sheets is exposed. Things.

In the present invention, the pressurized gas is blown toward the boundary between the sheets, and in that state, the place where the pressurized gas is blown from the end of the joint to the other end is moved, and the inspection is sequentially performed. And finally spraying over the entire length of the joint to terminate the inspection.

Normally, when the portion is sufficiently bonded, the pressurized gas flows around the shape of the joint and generates a sound peculiar to the state. However, if there is a portion that cannot be bonded or is not sufficiently bonded to the joining portion, the pressurized gas flows into the gap between the sheets, and the flow of the gas changes. Therefore, a sound different from the sound generated when the gas is flowing is generated.

With the pressurized gas being blown onto the joint, the position to be blown is gradually shifted, and it is possible to specify that a portion that produces a sound different from the sound in the normal state is a poorly-joined portion.

Although the type of the pressurized gas to be blown is not particularly limited, air is usually used, and an air nozzle 5 connected to a compressor can be used as the blowing means.

Next, the pressure of the pressurized gas to be blown is
It is necessary to have a pressure that generates a sound that can be sufficiently detected, and a pressure that does not damage the joint by blowing gas, and 5 to 10 kg.
It is preferable to carry out within the range of f / cm ² . 5kgf /
If it is less than cm ² , a sufficient volume cannot be generated, and even if the pressure exceeds 10 kgf / cm ² ,
It does not provide a substantial effect without damaging the joint or making the handling of the air nozzle difficult or increasing the risk in the inspection work.

The angle at which the pressurized gas is blown is preferably set under such conditions that the volume and sound quality generated by the blown angle change, and that sufficient sound volume and sound quality are obtained and easy to detect. The angle θ with respect to the sheet is set within the range of 10 to 60 °.

If the angle θ is less than 10 ° or more than 60 °, the pressurized gas does not properly hit the joint, and it is difficult to detect sound quality, which is not preferable.

Although it is a sound detecting means, it is also possible to detect by a human's hearing. In such a case, since there is an individual difference in the hearing, the sound differs depending on the person, but generates a sound volume that can be heard by a person performing the test. The pressure of the pressurized gas to be blown and the direction of the blow.

In addition, the generated sound is received by a microphone,
It is also possible to judge the signal by using a device such as an oscilloscope to detect a change in sound quality.

The waterproof sheet and the water-shielding sheet forming the joint to which the inspection method of the present invention is applied are not particularly limited in the material, and vulcanized rubber such as EPDM (ethylene propylene rubber) or HDPE (high density polyethylene),
Various types of sheets such as LDPE (low-density polyethylene), PP (polypropylene), TPO (thermoplastic olefin), and asphalt-impregnated sheets are included. Usually, those thicknesses are used in the range of 0.8 to 4.0 mm. If the thickness is less than 0.8 mm, the impermeable sheet is likely to be damaged due to insufficient strength, and if it exceeds 4.0 mm, the step at the joint becomes large. Not water-tight.

The joining method is not limited at all, and may be a method using a natural vulcanized rubber tape for vulcanization bonding, a general adhesive, or a method using a cyanoacrylate-based instant adhesive. Absent. In addition, depending on the material of the sheet, it can also be used for welding using a solvent or joining by heat fusion.

In any application where the watertightness of the joint is required, it is possible to carry out an inspection for a joint where a joint failure such as a gap is not allowed. Even if the joint is covered with a separate tape from above and the boundary of the joint is eventually hidden, before the separate tape is covered, Since the inspection method of the present invention can be performed in a state where the boundary is exposed,
Such cases are also included in the present invention.

Further, the movement along the longitudinal direction of the joint while blowing the pressurized gas does not need to be continuously performed from one end of the joint to the other end. No problem.

[0034]

EXAMPLES The effects of the present invention will be confirmed below with reference to examples of the present invention and comparative examples.

Example 1 1.5 mm made of EPDM
The widthwise ends of two 1200 mm wide x 12 m long sheets are overlaid with a 100 mm bond allowance,
For the bonding margin, a natural vulcanized rubber tape was interposed between the sheets, and the sheets were rolled and left to adhere for 24 hours. 1mmφ, 5mmφ, 10mm in diameter over the length direction of the joint
3 kinds of φ, 100mm in length and 3 rod-shaped foreign objects made of iron
A portion with poor bonding was artificially prepared by being interposed between the portions.

After joining, 5 kgf using an air nozzle
/ Cm ² of compressed air at a 45 ° angle to the sheet.
Pressurized air was blown from the distance of 00 mm to the boundary between the sheets at the joint. Inspection of the sheet joint was performed while moving the spraying position along the longitudinal direction of the joint in the sprayed state. The changes in the sound produced were captured by human hearing.

Table 1 shows the degree of detection of three defective joints.

Example 2 The pressure of the pressurized air was increased to 7 kgf /
Inspection of the sheet bonding portion was performed under the same conditions as in Example 1 except that cm ² was used. The sound generated was captured by human hearing. Table 1 shows the degree of detection of three defective joints.

Example 3 An inspection of a sheet joint was performed under the same conditions as in Example 1 except that the direction of blowing the pressurized air was 60 ° with respect to the sheet. Table 1 shows the degree of detection of three defective joints.

Comparative Example 1 The pressure of the pressurized air was 3 kgf /
Inspection of the sheet bonding portion was performed under the same conditions as in Example 1 except that cm ² was used. The sound generated was captured by human hearing. Table 1 shows the degree of detection of three defective joints.

[Comparative Example 2] The pressure of the pressurized air was increased to 15 kgf.
Inspection of the sheet joint was performed under the same conditions as in Example 1 except that / cm ² was used. The sound generated was captured by human hearing. Table 1 shows the degree of detection of three defective joints.

COMPARATIVE EXAMPLE 3 A sheet joint was inspected under the same conditions as in Example 1 except that the direction of blowing the pressurized air was set to 0 ° with respect to the sheet. Table 1 shows the degree of detection of three defective joints.

[Comparative Example 4] An inspection of a sheet joint was performed under the same conditions as in Example 1 except that the direction of blowing the pressurized air was 90 ° with respect to the sheet. Table 1 shows the degree of detection of three defective joints.

[0044]

[Table 1]

From the results in Table 1, the range of the pressure of the pressurized gas and the angle of spraying the pressurized gas defined in claim 2 and claim 3 is a reasonable range for implementing the inspection method of the present invention. Understand

[0046]

As described above, according to the first aspect of the present invention, in a method of inspecting a sheet joint in which sheets used for waterproofing and waterproofing are joined, a pressurized gas is blown to a boundary of the joint. It is characterized by detecting a defective bonding portion by detecting a change in generated sound.

By adopting such a method, it is not necessary to previously form the joint portion into a specific structure when inspecting the sheet joint portion, and the inspection operation itself is a very simple operation of merely blowing gas. Since the inspection can be performed, the inspection itself can be performed more simply and with reduced cost.

According to the second aspect, the pressure of the pressurized gas to be blown is set in the range of 5 to 10 kgf / cm ² , so that a sound volume sufficient to detect a change in sound can be generated.

Further, in the third aspect, the angle at which the pressurized gas is blown is in the range of 10 to 60 ° with respect to the sheet.

By doing so, it is possible to reduce the pressure of the gas to be blown, and to generate a sound change that can be sufficiently detected.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an inspection method according to the present invention.

FIG. 2 is a cross-sectional view corresponding to FIG. 1, in which the inspection method of the present invention is applied to a defective bonding portion.

[Explanation of symbols]

 Reference Signs List 1 sheet 2 sheet 3 joint 4 boundary 5 air nozzle

Claims (3)

[Claims] 1. A method for inspecting a sheet joint in which sheets used for waterproofing and water-shielding are joined to each other by capturing a change in sound generated by blowing a pressurized gas to a boundary between the sheets at the joint. A method for inspecting a sheet joint, wherein a defective joint is detected. 2. The pressure of the pressurized gas to be blown is 5 to 10 k.
^{2. The} method for inspecting a sheet joint according to claim 1, wherein the value is gf / cm ² . 3. The method according to claim 1, wherein the angle θ with respect to the sheet to which the pressurized gas is blown is in the range of 10 to 60 °.