JPH0148073B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applied to repair by forming a resin lining coating on the inner surface of existing pipes such as gas pipes and water pipes. This relates to a method for repairing the inner surface of existing pipes.

[Conventional technology]

Conventionally, as a method for repairing the inner lining of an existing piping system as described above, prior art techniques such as those disclosed in Japanese Patent Application Laid-open No. 54-31622 and Japanese Patent Application Laid-open No. 55-39274 are known.

These prior art techniques use a thermosetting resin such as an epoxy resin as a lining agent, and use a pressurized air flow to diffuse and flow the resin into the pipes of the existing piping system, thereby adhering to and solidifying the inner wall surface of the pipes. At this time, the airflow pressure at which the lining resin is introduced and distributed is conventionally a high pressure airflow of about 2Kg/cm ² to 7Kg/cm ² in the existing pipe, and the flow velocity is also high speed of 80m/s to 100m/s. It was hot.

[Problem to be solved by the invention]

By the way, when repairing the lining of an existing piping system using the conventional prior art technology as described above, the first problem is that in the conventional case, the lining resin is forced into the pipe using a high-pressure, high-speed airflow. If, for example, a corrosion hole has occurred in the existing pipe to be repaired, there is a problem that the corrosion hole may enlarge or damage the pipe during lining repair, and the lining resin may leak from the corrosion hole into the pipe. There were problems such as the inability to form a lining coating film to reliably close the corrosion holes rather than causing blow-through to the outside.

As a means to solve these problems, the inventor of the present invention has devised the idea of making the lining resin flow with a low-pressure airflow that has a slight pressure difference of about 0.3 kg/cm ² with respect to atmospheric pressure. .

In this method, the lining resin flows at a low pressure, so in order to flow the lining resin over a predetermined length, a low-viscosity resin must be used as the lining resin. First, since this reduces the thickness of the lining coating formed on the inner surface of the pipe, for example, if the target of repair is a gas pipe, it is difficult to obtain the pipe strength that satisfies the specified shape retention required for a gas pipe. There was a problem that it could not be done.

An object of the present invention is to provide a method for repairing the inner surface of an existing pipe that can solve all of the above-mentioned problems.

[Means to solve the problem]

In order to achieve this objective, the inner surface repair method according to the present invention includes: (A) dividing the lining construction of the existing pipe of repair unit length into a first step and a second step; (B) in the first step, lining the existing pipe of the repair unit length; A low-viscosity resin with a viscosity of about 10,000 cps or less is made to flow in the existing pipe using a low-pressure air flow with a slight pressure difference of about 0.3 Kg/cm ² from atmospheric pressure. (C) In the second step, it is introduced into the above pipe. The lining wood is made of high viscosity resin of about 50,000 cps or more,
The method is characterized in that construction is carried out in multiple stages so as to cause the air to flow at a high pressure of about 2 to 7 kg/cm ² within the existing pipe.

[Effect]

In this type of repair method, even if there is a corrosion hole in the existing pipe, the airflow pressure that flows the lining resin in the first step is low, so the corrosion hole can be enlarged by the airflow, and the lining resin can be removed from the hole. A lining coating film can be formed on the inner surface of the pipe to block corrosion holes without blowing out, and since the lining resin is introduced in a low viscosity state, the flow of the resin is ensured for a relatively long time, and the required length is Lining can be applied by forming a resin coating on the inner surface of the existing pipe.

In addition, after forming a coating film to close the corrosion holes in the lining construction in the first step, we performed the lining construction using high-pressure airflow in the second step. There is no risk of spouting out of the tube, and the second
Since the lining resin is fluidized by high-pressure airflow during the process, the lining resin used can also be used in a high viscosity state, making it possible to make the lining coating sufficiently thick and achieve uniform lining thickness without dripping. .

In this way, the multi-stage lining construction in the first and second steps forms a double lining coating inside the pipe, making it possible to form the coating to a predetermined thickness and improving shape retention. An internal repair is achieved with fully satisfactory pipe strength.

〔Example〕

Hereinafter, the method of the present invention will be explained based on specific examples shown in the drawings. In the figure, reference numeral 1 denotes a compressor, and a compressed air outlet side of the compressor 1 is communicated with a header 2. The header 2 is connected to an air heater 4 via a governor 3, and the air heater 4 uses steam supplied from the boiler 5 through a pressure reducing valve 6 and compressed air from the header 2. heat exchange between them to produce a carrier gas stream at positive pressure. The carrier gas stream is passed via a pressure regulator 7 to a gas flow generator 8 and brought to the resin supply head 9 in the desired air flow form, for example swirl or vortex. On the other hand, the pressure regulator 7
is connected to the resin supply head 9 via the bypass path 10.
This bypass passage 10 is supplied with a thermosetting resin such as an epoxy resin as a lining agent from resin injection means, for example, a first resin tank 11 and a second resin tank 11a.

The first resin tank 11, the second resin tank 11
Resin of the same material is housed in each of the tanks 11 and 11a, and the resin is supplied from the tanks 11 and 11a to the bypass path 10 by dropping a drop into the heated air or by spraying the resin. In this embodiment, a method is adopted in which resin is injected from inside the tanks 11 and 11a by the pressure of compressed air supplied from the header 2 via the pressure regulator 12.

Further, the resin is used in temperature controllers 13 and 13a.
As a result, the temperature is controlled in the first resin tank 11 and the second resin tank 11a, respectively, and the viscosity is maintained at a predetermined level. That is, in the first resin tank 11, the resin is maintained at a high temperature of about 60°C within the allowable limit by the temperature controller 13.
It is designed to maintain a low viscosity state of about 10,000 cps or less, and in the second resin tank 11a, the temperature is adjusted to about 15°C by the temperature controller 13a to maintain a low viscosity of 50,000 cps.
It is designed to maintain a high viscosity state exceeding a certain level.

Note that symbols 14 and 14a in the figure indicate the first and second resin tanks 11, 11a and the bypass path 1.
0, 15 is a safety valve provided downstream of the governor 3, 16 is a flow meter, 17 is a pressure gauge,
18 is a thermometer.

Further, in the illustrated embodiment, an abrasive injector 19 is connected downstream of the airflow generator 8 via a valve 20, so that compressed air is also supplied from the header 2 to the abrasive injector 19. It's getting old,
When the valve 20 is opened, the abrasive can be supplied downstream of the airflow generator 8 with the compressed air. This is to polish the inside of the existing pipe A to be repaired (target existing pipe system including conduits and supply pipes) to remove rust, etc., prior to lining with resin.

The resin supply head 9 is connected to one inlet side of the existing pipe A through a conduit, and valves 21a and 2 are connected to the other outlet of the existing pipe A.
1b, a lining agent recovery device 22a and an abrasive recovery device 22b are connected to a conduit 2 which is branched into two.
Connected via 3. And the recovery device 2
A vacuum pump 24 is connected downstream of 2a and 22b, and applies negative pressure to the outlet of the existing pipe A. In addition, the vacuum pump 24 includes:
A bypass 25 is provided in parallel arrangement, which is equipped with a valve 26.

In carrying out the inner lining construction of the existing pipe A using the above-mentioned apparatus, the present invention requires a first step and a second step.
The resin is divided into the following steps: Compressor 1
is carried into the existing pipe A by the air flow sent by the drive.

First, in the first step, the first resin tank 11
From the side, the resin made into a low viscosity state of about 10,000 cps or less by the temperature controller 13a is heated as a lining agent as it passes from the compressor 1 through the header 2 → governor 3 → air heater 4 → pressure regulator 7 and into the bypass path 10. It is injected into the air stream, where it is dispersed and atomized. In addition, during this first step, the pressure of the carrier gas flow (heated air) is set to a low pressure of, for example, +0.3 kg/cm ² in the existing pipe A by adjusting the pressure regulator 7. ,
At this time, the valve 14a on the second resin tank 11a side
is closed. Then, the valve 26 is opened and air is supplied from the bypass 25 to the vacuum pump 24.
The suction negative pressure by the vacuum pump 24 is set to a low negative pressure of about -0.3 kg/cm ² , for example, by allowing some circulation.

Even if the resin is a thermosetting resin, it will not solidify within its usable life, and the resin in the first resin tank 11 is kept in a low viscosity state of about 10,000 cps or less by temperature control. Resin supply head 9 has better dispersion in the air stream and is made into finer particles.
When the carrier gas stream is passed through the existing pipe A and is flown by the carrier gas stream, the carrier gas stream can flow over a predetermined distance even at a low pressure.

During this flow process, the supported gas flow is introduced into the existing pipe A in a swirling or eddy state by the action of the air flow generator 8, and due to the flow, the resin adheres to the inner wall of the pipe and solidifies, forming a lining. Coating film B is formed.

At this time, due to the action of vacuum pump 24, -0.3
Since a low negative pressure of about Kg/ ^cm2 is applied to the exit side of the existing pipe A, the kinetic energy of the supported gas flow is promoted and the flow distance is extended to a predetermined length, and the suction effect of the low negative pressure is Since the flow directionality of the carrier gas flow in the existing pipe A is given by The resin coating film B can be lined on the inner surface of the existing pipe A.

In this case, the carrier gas stream that flows the lining resin has a slight pressure difference with respect to atmospheric pressure.
The system is set to a low positive pressure of about 0.3Kg/ ^cm2 and a low negative pressure of about -0.3Kg/ ^cm2 , so even if there is a pinhole-shaped corrosion hole in the existing pipe A, the lining resin can be removed from the hole. The inner surface of the pipe can be lined with the resin coating B so as to block the holes without spewing out.

After the above-mentioned first step of lining has been carried out to the end of the existing pipe A of the required repair unit length, the second step is to adjust the pressure of the carrier gas flow to, for example, 2 In addition to setting the pressure to a high pressure of ~7Kg/ ^cm2 , in this second step, the second
By the temperature controller 13a from the resin tank 11a side
A resin whose temperature is adjusted to a high viscosity state of about 50,000 cps or more is injected into the heated air passing through the bypass passage 10 as a lining agent. As a result, the high-viscosity resin is passed through the existing pipe A by a high-pressure carrier gas flow, thereby forming an additional double lining coating layer C on top of the lining coating B formed in the first step. Particularly in the second step, since the temperature of the lining resin is adjusted to a high viscosity state, a relatively thick lining coating layer C is formed.

During the lining construction in this second step, the corrosion holes in the existing pipe A have already been blocked by the lining construction in the first step using low pressure and low negative pressure.
Lining construction can be achieved without any problems even with high-pressure supported gas flow. Then, by performing the lining construction in the second step within the time when the resin coating film B formed in the first step is not completely solidified, the first
Since the resin coating film in the second step is adhered and solidified on top of the lining coating film B in the process, the inner surface of the existing pipe A is coated with double lining coating layers B and C. The film layer can be formed thick to a predetermined thickness.

Furthermore, in this embodiment, the same resin material is selected for the first resin tank 11 and the second resin tank 11a, but different resins may be selected as long as they are compatible with each other. It changes the viscosity into low and high viscosity states. Further, in one tank, the temperature may be controlled to switch to a low viscosity state in the first step and to a high viscosity state in the second step. In addition, the temperature of the carrier gas flow can also be controlled accordingly, from high temperature in the early stage to low temperature in the latter stage.

〔Effect of the invention〕

As explained above, the present invention performs lining construction on an existing pipe of a required repair unit length.
Low viscosity resin of about 10000cps or less and 0.3Kg/
The first step is to flow the resin into the pipe with an airflow set to a low pressure of about ² cm2, and the second step is to flow the resin into the pipe with a high viscosity resin of about 50,000 cps or more and an airflow set to a high pressure of about ² to 7 kg/cm2. Since the construction was divided into two stages and carried out in multiple stages, the following effects can be obtained.

(1) Even if there is a corrosion hole in the existing pipe, the airflow pressure that flows the lining resin in the first step is low, so the corrosion hole will not be enlarged by the airflow and the lining resin will not spray out from the hole. It is possible to form a lining coating film on the inner surface of the pipe so as to close corrosion holes without any problems, and since the lining resin has a low viscosity, the flow of the resin is ensured for a relatively long time. Lining can be applied to form a coating.

(2) In addition, after forming a coating film to close the corrosion holes in the lining construction in the first step, the lining construction was performed using high-pressure airflow in the second step, so even if the lining is passed through the high-pressure airflow, the lining resin There is no risk of the resin being blown out of the pipe from the corrosion holes, and since the lining resin is fluidized by high-pressure airflow in the second step, the lining resin used can also be of high viscosity, making it possible to maintain a sufficient thickness of the lining coating. It is possible to achieve lining construction with a uniform thickness and no sagging.

(3) In this way, a double lining coating film is formed inside the pipe by the multi-stage lining construction in the first and second steps, so the coating film can be formed to a predetermined thickness; Inner surface repair with pipe strength that satisfies shape retention is achieved.

[Brief explanation of drawings]

The drawing is a schematic configuration diagram of an example embodying the method of the present invention. 1... Compressor, 2... Header, 3... Governor, 4... Air heater, 5... Boiler, 6...
Pressure reducing valve, 7...pressure regulator, 8...airflow generator,
9...Resin supply head, 10...Bypass path, 1
1... First resin tank, 11a... Second resin tank, 12... Pressure regulator, 13, 13a... Temperature regulator, 14, 14a... Valve, 15... Safety valve, 16... Flow meter, 17...Pressure gauge, 18...
Thermometer, 19... Abrasive injector, 20... Valve, 21a, 21b... Valve, 22a, 22b
...recovery device, 23 ... conduit, 24 ... vacuum pump, 25 ... bypass, 26 ... valve.

Claims (1)

[Scope of Claims] 1. Lining construction for an existing pipe of repair unit length in a method in which lining is performed by spreading and flowing a lining resin in an air flow to form a coating film on the inner surface of the pipe within the pipe line of the existing pipe. In the first step, low viscosity resin with a resin viscosity of about 10,000 cps or less is heated against atmospheric pressure in the existing pipe.
The lining resin introduced into the pipe is made to have a high viscosity of about 50,000 cps ^or more, and the lining resin introduced into the pipe is made to have a high viscosity of about 50,000 cps or more, and the amount of 2 to 7 kg in the existing pipe is made to flow with a low-pressure air flow with a slight pressure difference of about 0.3 Kg/cm2. A method for repairing the inner surface of existing pipes, which is characterized by carrying out construction in multiple stages using a high-pressure airflow of about / ^cm2 . 2 In the first step, the temperature of the resin introduced into the tube is controlled to about 60°C by a temperature control device, and in the second step, the temperature of the resin introduced into the pipe is controlled to about 15°C by a temperature control device. 2. A method for repairing an inner surface of an existing pipe according to claim 1, wherein the method is performed by repairing the inner surface of an existing pipe.