JPH0131076B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for sealing the inner surface of a conduit, and more particularly, to a method for sealing a leakage portion by transporting a liquid sealant in the form of a mist into a conduit by pneumatic flow.

A prior art technique for sealing a leaking part in a conduit from the inside is a technology in which a liquid sealant is made into a mist and introduced into the conduit along with a gas such as air, and the sealant is attached to the leaking part to seal it. has traditionally been practiced. However, if there is a leak in the threaded part of the threaded joint 3 that connects the conduits 1 and 2 as shown in FIG. At the leakage location, the amount of sealant deposited differs between the upstream surface 5a and the downstream surface 5b in the sealant introduction direction 4.

Therefore, the upstream side surface 5a and the downstream side surface 5
In order to completely prevent leakage of b, a large amount of sealant must be introduced, and therefore the time for feeding the sealant also becomes long. Moreover, in such a case, a large amount of sealant will adhere to parts of the conduits 1 and 2 other than the leakage parts, and a large amount of sealant will be wasted, which is uneconomical.

This kind of thing also occurs when the plug 6 is screwed into the middle of the conduit 7 as shown in Fig. 2, or when a leak hole 9 is formed in the middle of the conduit 8 as shown in Fig. 3. Therefore, the sealing work required a long time and the sealant was wasted.

To summarize, conventionally, a liquid sealant is atomized and entrained in a gas such as air from one end of a conduit, with the particle size of the sealant and the flow rate in the conduit remaining constant without changing. It is introduced into the pipe, and the sealant is applied to the inner surface of the pipe to seal the leakage part.

According to such prior art, the sealant does not adhere uniformly to a portion where the inner diameter of the pipe changes, such as a joint portion of a conduit, and therefore it is not possible to reliably seal a leaking portion.

In such prior art, when trying to apply sealant sufficiently and uniformly to parts where the inner diameter of the pipe changes, such as at joints, a large amount of sealant is used, making the sealant unnecessary. The sealant will be wasted as it will stick to other areas.

An object of the present invention is to provide a method for sealing the inner surface of a conduit that can reliably seal the inside of the conduit with a small amount of sealant.

Means for Solving the Problems The present invention is a method for sealing the inner surface of a conduit, in which a sealing agent is introduced from the end of the conduit to seal the inner surface of the conduit. The sealant is introduced for a predetermined period of time so that the sealant mainly adheres to either the upstream side or the downstream side, and then the particle size of the sealant and the flow rate in the conduit are determined. The sealant is introduced for a predetermined period of time by changing at least one of the pipes so that the sealant mainly adheres to the other surface, either the upstream side surface or the downstream side of the portion where the inner diameter of the pipe changes. This is a method for sealing the inner surface of a conduit.

Effect According to the present invention, first, the particle size of the sealant and the flow velocity in the conduit are determined so that the sealant is applied to either the upstream surface or the downstream surface of the portion where the pipe inner diameter changes. The sealant is introduced for a predetermined period of time to ensure primary adhesion. Thereafter, at least one of the particle size and the flow rate in the pipe is changed so that the sealant mainly adheres to the other of the upstream and downstream surfaces of the part where the pipe inner diameter changes. and introduce the sealant for a predetermined period of time. This makes it possible to apply the sealing agent uniformly even in areas where the inner diameter of the pipe changes, such as a joint part of a conduit. Therefore, without using an unnecessarily large amount of sealant,
It becomes possible to perform sealing reliably using as little sealant as possible.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 4 is a system diagram of a sealing device according to an embodiment of the present invention. A nozzle 11 is inserted into the conduit 10 to be sealed. This nozzle 11 is a conduit 12
The other end of the conduit 12 is immersed in a sealant 14 stored in a storage tank 13 . In the middle of the pipe line 12, a pot 15 and a pressure gauge 16 are provided in order from the upstream side. One end of a pipe 17 is connected to the pipe 12 downstream of the pressure gauge 16, and the other end of the pipe 17 is connected to a compressor 18. A pot 19 and a pressure gauge 20 are provided in the middle of the pipe line 17 in this order from the upstream side. Conduit 1
The upstream side of the tank 19 of No. 7 is connected to the storage tank 13 via a branch pipe 21. The storage tank 13 is hermetically sealed and pressurized by compressed air introduced from a compressor 18, thereby introducing the sealant 14 into the pipe line 12. At the end of the conduit 10 there is a conduit 2
2 is connected, and the other end of this pipe line 22 is connected to a forced air blower 23. A pot 24 and a flow meter 25 are provided in the middle of the pipe line 22 in this order from the upstream side.

The sealant flowing through the pipe 12 is ejected in a mist form from the nozzle 11 together with the compressed air flowing in from the pipe 17. The atomized particle size of the sealant 14 is adjusted by changing the pressure of compressed air and the pressure applied to the sealant 14. The sealing agent 14 sprayed from the nozzle 11 is transported inside the conduit 11 along with the air blown from the forced air blower 23, and is evenly adhered to the entire surface of the inner surface of the conduit 10 at the same time as the leaking part, thereby performing a sealing function. .

Techniques for sealing the inside of the conduit 10 by pneumatically transporting the atomized sealant as described above are conventionally known, but according to the present invention, the atomized particle size and flow rate of the sealant (the embodiment shown in FIG. In other words, by changing the flow rate of air, the sealant can be applied evenly to the upstream side and the downstream side of the sealant feeding direction 26 in the leakage portion.

FIG. 5 is a graph showing which surface the sealant adheres to, the upstream side and the downstream side in the sealant feeding direction, depending on the particle size of the sealant and the speed at which the sealant is transported. In FIG. 5, the broken line 30~
36 indicates particle sizes of 20, 15, 13, 10, 7, 5, and 3μ, respectively. Furthermore, in each of the broken lines 30 to 36, the thick solid line indicates the range where the sealant mainly adheres to the upstream surface along the feeding direction, and the thin solid line indicates the range where the sealant mainly adheres to the downstream surface along the feeding direction. The broken line indicates the laminar region where the Re number is 3000 or less, where the sealant settles and adheres only to the lower side of the pipe to be sealed. In addition, in Figure 5, the construction distance is
Indicates the distance at which the sealant will adhere evenly to the inner surface over the entire length of the tube to be sealed.

In addition, Figure 5 shows the specific gravity on the inner surface of a pipe with a nominal diameter of 1B.
This is a graph showing experimental values when a sealing agent of 1.15 is attached, and a graph similar to that of FIG. 5 can be created depending on the pipe diameter and specific gravity of the sealing agent.

When sealing the inner surface of the conduit 10 with the sealant 14, first the entire length of the conduit 10 into which the sealant 14 is to be delivered, ie, the construction distance of the conduit 10 including the leakage portion, is determined. The nominal diameter of the conduit 10 is 1B,
The construction distance is, for example, 20 m. Then, the atomized particle size of the sealant 14 to be sprayed from the nozzle 11 is appropriately selected. If this particle size is, for example, 10 μ, the intersection of the thick solid line of broken line 33 in FIG. 5 and the construction distance of 20 m is the transport speed of the sealant, which is 6 m/s in FIG. Therefore, if the sealing operation is performed using the sealing device shown in FIG. 4 with the atomized particle size of the sealant 14 set to 10μ and the air velocity within the conduit 11 adjusted to 6m/s, The sealant mainly adheres to the upstream surface along the sealant feeding direction 26 at the leakage point of the conduit 11 .
This sealing operation is performed for a certain period of time determined by experience.

Next, an operation is performed in which the atomized particle size and feeding speed of the sealant 14 are changed so that the sealant mainly adheres to the surface on the downstream side along the sealant feeding direction 26. That is, in FIG. 5, if the atomized particle size is selected to be 15μ, the intersection of the thin solid line of the broken line 31 and the construction distance of 20 m is the feeding speed of the sealant 14, and from FIG. 5, the feeding speed is 4 m/s. Become. Therefore, the atomized particle size of the sealant 14 is controlled by the sealing device shown in FIG.
The sealing operation was carried out for a certain period of time by adjusting the air flow rate to 15 μm and 4 m/s.

By doing this, the sealant 14 is evenly applied to the upstream side and the downstream side of the leaking portion of the conduit 10 along the sealing agent feeding direction 26, and in a relatively short time. Sealing can be achieved using as little sealant as possible.

In the above-mentioned sealing operation, in determining the time for the sealing operation, first, the leakage amount from the leakage portion of the conduit 10 is measured, and the leakage hole diameter of the leakage portion is estimated from the leakage amount. Then, the sealing operation only needs to be performed for a time sufficient to spray the amount of sealant necessary to seal the leakage hole.

In Fig. 5, at the point of contact between the thick solid line and the thin solid line, the same amount of sealant adheres to the upstream and downstream surfaces, but the amount of adhesion is small, and the amount of adhesion is almost inversely proportional to the installation distance. . Note that the construction distance refers to the inner surface of the part where the inner diameter of the pipe does not change, and the
This refers to the distance at which the sealant adheres evenly to the surface corresponding to the thick solid line or thin solid line in the figure.

Figure 6 shows the internal pressure in a cleaning screw joint with a nominal diameter of 1B.
It is a graph showing the relationship between leakage hole diameter and leakage amount when 300mmH ₂ O is applied. According to FIG. 6, the leak hole diameter can be estimated from the leak amount. In addition, although Fig. 6 shows the case of a cleaning threaded joint with an internal pressure of 300 mmH ₂ O and a nominal diameter of 1B, the conduit 10
It is sufficient to determine in advance through experiments the cases in which pinholes or parallel gaps are formed in the side wall of the case.

In this way, by changing the atomized particle size and the introduction speed of the sealant 14, it is possible to seal the leaking part in a short time and using only the minimum amount of the sealant 14.

For example, from a threaded joint in the middle of a conduit with a nominal diameter of 1B and a construction distance of 20 m, the internal pressure is 300 mmH ₂ O and 100 c.c./
FIG. 7 shows the change over time in the amount of leakage when the sealing operation is performed by changing the atomized particle size and feeding speed of the sealant as described above. In FIG. 7, a curve 37 shows a state in which sealing is performed with the sealant 14 having an atomized particle size of 10 μm and a feed speed of 6 m/s, and a curve 38 shows a state in which the sealant 14 has an atomized particle size of 15 μm and a feed speed of 4 m/s. Shows the state in which the seal has been applied. In this way, by changing the atomized particle size and feeding speed midway through, the amount of leakage could be reduced to zero in a short period of about one hour.

On the other hand, FIGS. 8 and 9 show the results of sealing the leakage of the threaded joint without changing the atomized particle size and feeding speed. Figure 8 shows sealant 1
4 is fed into the conduit at an atomized particle size of 10 μm and a feeding speed of 6 m/s, which are conditions for the sealant to adhere mainly to the surface facing the upstream side in the sealing agent feeding direction 26. 8th
In the figure, a curve 39 indicates the amount of leakage from the upstream side in the sealant feeding direction 26, and a curve 40 indicates the amount of leakage from the downstream side. As is clear from FIG. 8, the amount of leakage from the downstream side decreases slightly in response to time changes, but it hardly decreases after that.

FIG. 9 shows the sealant 14 in the sealant feeding direction 26.
The case is shown in which the atomized particles are fed into the conduit at a diameter of 15 μm and a feeding speed of 4 m/s, which are the conditions that the atomized particles mainly adhere to the surface facing the downstream side of the pipe. In FIG. 9, a curve 41 shows the amount of leakage from the downstream side in the sealant feeding direction 26, and a curve 42 shows the amount of leakage from the upstream side. 9th
As is clear from the figure, the amount of leakage from the upstream side decreases slightly over time, but after that it hardly decreases.

Therefore, according to the present invention, the atomized particle size and feeding speed of the sealant that mainly adheres to the surface facing the upstream side and the surface facing the downstream side along the feeding direction of the sealant are selected, It can be seen that the seal construction time can be shortened by performing sealing while changing these construction conditions.

FIG. 10 is a system diagram of a sealing device according to another embodiment of the present invention. In this embodiment, conduits 44 and 45 are connected to the ends of conduit 43 to be sealed. These pipes 44 and 45 are connected to the sealant storage container 4.
6, 47 was thrust into the interior from the top. tube 44,
The lower end of 45 is located slightly above the sealant liquid level. Ultrasonic transducers 48 and 49 are provided on the lower surface of each sealant storage container 46 and 47, respectively. These ultrasonic transducers 48 and 49 are
They are vibrated by ultrasonic oscillators 50 and 51 having different frequencies, respectively. Each sealant storage container 46,
One end of the pipes 52 and 53 are connected to the upper part of the pipe 47, and the other ends of the pipes 52 and 53 are connected to the three-way switching valve 54. The remaining connection end of the three-way switching valve 54 is
It is connected to a forced air blower 57 via a conduit 56 . A valve 58 and a flow meter 59 are installed in the middle of the pipe line 56.
will be provided.

According to this embodiment, the ultrasonic transducers 48, 49
Due to the vibration, the sealant in each sealant storage container 46, 47 is atomized. Furthermore, since the frequencies of the ultrasonic transducers 48 and 49 are different, the particle sizes of the sealants atomized in the sealant storage containers 46 and 47 are different. This atomized sealant is sent into the conduit 43 along with the air flow introduced from each of the conduits 44 and 45.

Therefore, the three-way switching valve 54 is operated to switch the valve 5.
By opening and closing 8, the sealant can be fed into the conduit 43 while changing the particle size and feeding speed.

In each of the above-mentioned Examples, experiments were conducted using a liquid prepared by mixing 5 to 10 parts by weight of cyanoacrylate and 95 to 90 parts by weight of dimethacrylic acid ester as the sealant. This sealant has a low viscosity (1 to 10 cp) that can sufficiently penetrate into minute gaps.
Moreover, it has the property of hardening after penetrating into minute gaps for a sufficient length, and is suitable as a sealant for leaky parts such as threaded joints. In addition, if the cyanoacrylate is less than 5 to 10 parts by weight,
Although a sufficient penetration length can be obtained in a short period of time, it is not suitable as a sealant because it does not harden. In addition, if cyanoacrylate exceeds 5 to 10 parts by weight,
It is unsuitable as a sealant because a sufficient penetration length cannot be obtained. Other substances may be used as the sealant.

As described above, according to the present invention, the atomized particle size and feeding speed of the sealant are changed to feed the sealant, so that the sealant can be applied to both sides along the axis of the conduit at the leakage part of the conduit. Can be applied evenly. Therefore, the amount of sealing agent used can be reduced, and the sealing time can be shortened. That is, in the present invention, when the sealant is introduced from the end of the conduit, at least one of the particle size of the sealant and the flow rate in the conduit is changed after a predetermined time has elapsed since the introduction of the sealant. As a result, even in areas where the inner diameter of the pipe changes, such as at conduit joints,
The sealant can be applied uniformly. Therefore, it is possible to seal a portion where the inner diameter of the pipe changes, and the amount of sealing agent used can be reduced.

[Brief explanation of drawings]

Figures 1, 2, and 3 are cross-sectional views for explaining the prior art, Figure 4 is a system diagram of an embodiment of the present invention, and Figure 5 shows the atomized particle size and feeding speed. Figure 6 is a graph showing the relationship between leakage hole diameter and leakage amount, Figures 7, 8, and 9 are graphs showing experimental results, and Figure 10 is a graph showing another implementation of the present invention. FIG. 2 is an example system diagram. 10, 43... Conduit, 14... Sealing agent.

Claims (1)

[Claims] 1. In a method for sealing the inner surface of a conduit by introducing a sealant from the end of the conduit, the particle size of the sealant and the flow velocity in the conduit are determined by adjusting the particle size of the sealant and the flow velocity in the conduit on the upstream side of the part where the inner diameter of the pipe changes or A sealing agent is introduced for a predetermined period of time so that the sealing agent mainly adheres to one of the downstream surfaces, and then at least one of the particle size of the sealing agent and the flow rate in the conduit is It is characterized by introducing the sealant for a predetermined time so that the sealant mainly adheres to either the upstream side surface or the downstream side surface of the portion where the inner diameter of the pipe changes. Method of sealing the inner surface of the conduit.