JPH0545313B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a lining repair method for the inner surface of existing pipes, such as gas pipes and water pipes, in which a resin lining film is formed on the inner surface of the pipe.

[Conventional technology]

In installed pipes such as gas pipes and water pipes, corrosion holes and cracks occur in the pipes over time, which can cause leaks. Therefore, as a rehabilitation repair method to repair leaks or preventive maintenance, Lining repair is performed by forming a coating using resin. Conventionally, as a lining repair method using this type of resin, the following method is known for existing pipes with relatively small pipe diameters. Spray airflow method For example, JP-A-54-127941
14826), Japanese Patent Application Laid-open No. 156046/1983, etc., a high-speed air flow is caused to flow into the construction pipe from one end thereof, and the resin is carried by this air flow. A method in which a coating is formed using resin airflow that is blown into the pipe and adheres to the inner surface. Pig lining method For example, as in the prior art disclosed in Japanese Unexamined Patent Publication No. 55-44320, two pigs are introduced into the pipe under construction, a resin is interposed between the pigs, and the pigs are moved. A method of forming a coating by causing the advancing resin to flow backwards from the peripheral surface of the rear pig and applying it to the inner surface of the pipe. Resin plug flow method For example, JP-A-57-105270, JP-A-58-
As in the prior art disclosed in Publication No. 6272, etc., fluid resin is injected into the construction pipe from the opening at one end in the form of a plug over a required length so as to close the inside of the pipe. A method in which a coating is formed by a resin film that remains on the inner surface of the tube during the process of causing the plug to flow due to the pressure difference generated in the tube between the front and back.

[Problem to be solved by the invention]

By the way, when repairing the lining of installed pipes using the above-mentioned conventional method, the pipe to be repaired is, for example, a small-diameter pipe with a bent part such as an elbow or a part with a change in diameter in the middle of the pipe. When dealing with piping systems (such as supply pipes in gas piping) where pipes are interposed, the above-mentioned repair method using the pig lining method has problems in application because the pig gets stuck in the middle of the pipe and becomes unable to move. There is a point. Therefore, in the construction of lining repair for piping systems as described above, the above-mentioned repair method using the spray airflow method is generally put into practical use. However, when using this repair method, there is a restriction that the resin used must have a low viscosity (for example, 15,000 cps or less) because the resin is supported by a high-speed air flow and blown into the pipe. The thickness of the lining film formed on the lining was also thin, almost 0.5 mm or less, and there was a problem that the lining film could not be made thicker. In this respect, the repair method using the resin plug flow method described above is attracting attention as a method that allows the lining film formed on the inner surface of the pipe to be appropriately thick. However, the prior art techniques disclosed in Japanese Patent Laid-Open Nos. 57-105270 and 58-6272, which have been previously proposed as this construction method, have the following problems. In other words, in the above-mentioned prior art, a resin plug of a required length injected into a pipe is caused to flow by the pressure difference created between the front and back. If the amount of resin decreases due to the formation of a film due to the progress of flow, a phenomenon occurs in which the flow speed of the resin plug flow gradually increases in accordance with the decrease in the amount of resin. The flow rate of this resin is, for example,
As suggested in Japanese Patent Application No. 50-28456, it is known that this is related to the thickness of the lining film formed on the inner surface of the pipe, and therefore, in the above-mentioned prior art, the flow velocity of the resin plug flow changes sequentially. In particular, there was a problem in that the thickness of the coating formed on the inner surface of the tube was non-uniform over the entire length of the tube. Furthermore, when the resin plug flow advances in the pipe, the amount of resin decreases after traveling a predetermined distance and blow-by occurs, but in this case, in the above-mentioned prior art, consideration is not given to attenuating the pressure difference as the flow progresses. Therefore, when the resin blows through at the moving end of the flow, the resin blows through with great force due to the high pressure difference, causing large pressure fluctuations inside the pipe, and this pressure fluctuation adversely affects the uncured lining film formed on the inner surface of the pipe. This also leads to problems such as irregularities in the film thickness, resulting in non-uniform film thickness. On the other hand, as in the construction method already proposed by the present inventors, a launcher having a control device is connected to the injection side pipe end of the resin plug, and a launcher having a control device is connected to the other outlet side pipe end as the resin plug flows in the pipe. A receiver equipped with a pressure gauge, a flow meter, etc. that detects the changing pressure inside the discharge pipe and the amount of discharged air is connected, and the flow rate of the resin plug in the pipe is kept constant based on the signals that detect the pressure inside the discharge pipe and the amount of discharged air. There is a lining repair method for the inner surface of a pipe that maintains the lining at the rear end of the pipe, but this method detects and controls the internal conditions of the pipe, such as the pressure and flow rate at the rear end of the pipe. However, there were problems such as it was difficult to accurately detect the pressure inside the discharge pipe and the amount of discharged air from the end of the pipe, and it was difficult to control the pushing speed of the resin at a constant level. . An object of the present invention is to provide a lining repair method that solves the above-mentioned problems in the repair method using the resin plug flow method.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention injects fluidized liquid resin into a construction pipe to be repaired from an opening at one end in the form of a plug over a required length so as to close the inside of the pipe, and then inserts the resin plug. , in a pipe inner surface lining repair method in which the flow is set in advance at a set speed necessary to form the target lining film thickness based on the pipe diameter, resin viscosity, and other related conditions, the injection side pipe end of the resin plug A launcher having a control device for controlling the gas flow rate of the pressurized gas introduced into the tube is connected to the tube, and the control device measures the flow rate and pressure inside the tube of the forced gas introduced into the tube, A means for detecting the position of the resin plug, and a means for intermittently detecting the position of the resin plug and detecting the resin flow speed from the difference in the position of the resin plug at each predetermined time, It is characterized in that the pressure of the pushing gas inside the tube is controlled so as to keep the flow rate constant.

[Effect]

In this type of repair method, the position of the resin plug in the pipe and the resin flow speed are detected by a control device from the launcher side connected to the injection side pipe end of the resin plug, and the flow speed of the resin is controlled to be constant. Even if there is a branch pipe or a leakage point on the rear end of the lining pipe, the flow of the resin plug can be controlled accurately without being affected by these, and uniform resin lining can be performed. . Furthermore, since resin lining can be performed using low-pressure pressing gas, corrosion holes will not be enlarged.

【Example】

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the drawings, FIG. 1 schematically shows an embodiment of the repair method according to the present invention, and reference numeral 1 indicates an existing pipe to be repaired. This existing piping 1 is an existing piping such as a gas pipe or water pipe installed underground or inside a building, and in particular, the existing piping 1 to be repaired by the present invention refers to a gas pipe. Generally speaking, it targets existing pipes with a relatively small diameter called supply pipes with a diameter of about 15 to 40 mm, and branch pipes with a diameter of about 40 to 150 mm. This existing piping 1 is divided into repair sections of a predetermined length when repaired, and a launcher 2 having a predetermined length is connected to an opening at one end of the section via a flange 3. A resin injector 4 is connected to the launcher 2 via an electromagnetic on-off valve 5 serving as a resin supply means, and a liquid lining is supplied from the resin injector 4 over a required length so as to fill and block the inside of the pipe. Resin A is introduced into launcher 2. Here, the lining resin A is a two-component curing resin at room temperature, which is a mixture of a main resin and a curing agent, and is a resin having thixotropic properties. Note that the resin injector 4 may be supplied with a resin in which a base resin and a curing agent have been mixed in advance using an air pressurized injector. Both may be mixed and supplied using a static mixer during the process. Further, the launcher 2 is equipped with an electromagnetic on-off valve 7 that operates in the opposite direction in conjunction with the electromagnetic on-off valve 5 of the resin injector 4, and behind it is a flow regulating valve that is computationally controlled by a computing device 6'. 11 and 16,
A small compressor 12 is connected to the compressor 12 via a control device 6 that includes flow meters 9 and 17 that measure the gas flow rates and pressure gauges 8 and 10 that measure the gas supply pressure. The flow rate is controlled by the control device 6, and the liquid is introduced into the launcher 2 and fed into the existing piping 1. Further, the compressed air from the compressor 12 is introduced into the launcher 2 via a three-way switching valve 13 controlled by the control device 6, and is also introduced into the resin injector 4 via a flow rate adjustment valve 14. The lining resin A is supplied via a pressurized sliding plate 15 provided in the resin injector 4 at a constant rate from the electromagnetic on-off valve 5 which is opened in conjunction with the electromagnetic on-off valve 7 controlled by the control device 6. A predetermined amount of the liquid is extruded and filled into the liner 2 under pressure. Next, to explain the work process of repair work using the above-mentioned device, first, the electromagnetic on-off valve 7 is closed, and the electromagnetic on-off valve 5 is opened to inject resin into the launcher 2 connected to the starting end opening of the existing pipe 1. A predetermined amount of lining resin A is injected from inside the container 4 in a liquid state. In this injection of resin A, lining resin A is
From inside the launcher 2, it is injected into the starting end side of the construction pipe 1 in the form of a plug over a required length so as to close the inside of the pipe. Hereinafter, this plug-shaped resin A injected will be referred to as a resin plug, and will be given the same symbol A as the resin. Next, when the filling of the resin plug A is completed, the electromagnetic on-off valve 5 is closed, and the electromagnetic on-off valve 7 on the side of the ventilation system is opened to transfer compressed air from the compressor 12 to the flow rate adjustment valve 11 by switching the three-way switching valve 13.
It is controlled to feed into the pipe from the end of the launcher 2 through the flow meter 9. As a result, the pressurized air acts to press the rear end surface of the resin plug A from behind, and the pressure of the static pressure imparts fluidity to the resin plug A, so that the resin plug A is placed in a columnar state on the launcher. 2
The fluid flows through the existing piping 1 from within. The compressive pressure applied to the resin plug A at this time is such that the initial pressure to impart fluidity to the resin plug A is approximately 1.5 kg/cm ² relative to atmospheric pressure, and When A flows through the existing pipe 1, its pushing force is reduced by the flow rate regulating valve 16 to a low pressure of approximately 0.6 kg/cm ² or less relative to atmospheric pressure. Due to the flow progress of this resin plug A, when flowing,
Due to the adhesive force against the wall surface as it flows while contacting the inner surface of the tube, the resin plug A remains on the inner surface of the tube as it progresses, and after passing through the resin plug, this residual resin lines the inner surface of the tube with the required thickness. Paint film 18
is formed uniformly. First, when the traveling speed V of the resin plug A is kept constant and the resin viscosity is changed, the lower the resin viscosity, the more the end face shape of the resin plug becomes a bullet shape as shown in FIG. 2, and the film thickness increases. The higher the viscosity, the more vertical the end face shape as shown in FIG. 3, and the thinner the film thickness becomes. In addition, when the resin viscosity is kept constant, the compression pressure a
If you increase the running speed of resin plug A by increasing
The end face shape of the resin plug A is bullet-shaped as shown in Fig. 2, and the film thickness is thick.If the compression pressure a is lowered and the running speed is slowed down, the end face shape of the resin plug A becomes as shown in Fig. 3. The film thickness becomes thinner due to the vertical end face shape. In other words, in terms of the relationship between the resin viscosity and the running speed V, if the resin plug A is flown and run so that the end face shape of the resin plug A becomes a bullet shape as shown in Fig. 2, the film thickness will be thick. Also, adjust the resin plug A so that it has a nearly vertical end face shape as shown in Figure 3.
It has been experimentally and theoretically confirmed that a thin film is formed when the material is flown. Therefore, in the repair method according to the present invention, first, the thickness of the lining coating film to be formed on the inner surface of the target existing pipe 1 is selected, and the thickness of the lining coating film to be formed is determined. Based on the selection, set the flow rate of resin plug A necessary to form the desired film thickness from repair-related conditions such as the diameter of the pipe to be repaired, the viscosity of the resin used, and the length of the filled resin plug. , so that the resin plug A flows through the pipe at the set flow rate.
The compressed air from 2 is controlled by the control device 6 to apply a required static pressure to the rear end surface of the resin plug A. In this case, the resin A used is a thixotropic resin as mentioned above, and when external force is applied to this type of resin, the coating structure is destroyed and a softening phenomenon occurs, and when the external force is removed, it takes a long time. Since it has the property of recovering to its original state with the passage of time, the pressing force of the resin plug A is the pressing force (approximately 0.6 kg/cm ² or less) when running in the pipe after flowing, as described above.
On the other hand, the initial pressing force for imparting fluidity is set at a somewhat higher pressure of about 1.5 Kg/cm ² . In the case of such a pressure setting, the initial pressing force acts on the inside of the pipe in the launcher 2 part, causing the existing piping 1
In addition, the pressing force inside the existing piping 1 is set to a low pressure of approximately 0.6 kg/cm ² or less so that there is a slight pressure difference with respect to atmospheric pressure. Even in the aged existing piping 1, the phenomenon of blow-through from corrosion holes can be reliably avoided. Further, the resin plug A flows in the pipe due to the pressing force, and the formation of a lining coating film progresses, and when the flow rate of the resin plug A decreases due to the formation of the coating film, the amount of resin plug A flows in response to the decrease in the amount of resin. The amount of air flowing into the pipe is controlled by the control device 6 and flow regulating valves 11 and 16 so that the pressure is attenuated and the flow rate of the resin plug A is constant. In other words, as the resin plug moves within the pipe and the amount of resin decreases, the flow rate of resin plug A tends to increase accordingly, but this flow rate is
It changes in relation to the pressure inside the pipe of the pushing gas introduced into the existing pipe 1, and the pressure inside the pipe also changes depending on the amount of pushing gas that has flowed into the pipe and the position of the resin plug, that is, the rear side of the resin plug. Since it is determined by the volume of the gas, the amount of pushing gas that has flowed into the pipe is measured by the flowmeters 9 and 17, and the pressure inside the pipe is measured at each point in time when the amount of gas in the pipe is measured. The speed of the resin plug A can be calculated from the change in the volume of the gas in the tube, that is, the change in the position of the resin plug A, using the device 6'. As a result, the flow adjustment valve 11 (R ₁ ) and the flow adjustment valve 16 (R ₂ ) are adjusted so that the control device 6 on the starting end side can obtain a pushing pressure that makes the flow speed of the resin plug A constant. The pressing force of the resin plug A is automatically attenuated so that the flow rate of the resin plug becomes constant as the amount of resin decreases. Hereinafter, the operation of the control device 6 that maintains the flow rate of the resin plug A constant will be explained in detail. First, if the amount of pushing gas that has flowed into the pipe is Q ₁ and the pressure inside the pipe is P ₁ , then the relationship is as follows: π/4・d ²・1 ₁・P ₁ =Q ₁・P ₀ ……(1) Therefore, Q ₁ , P ₀ , at a certain time T ₁
If P ₁ is measured, 1 ₁ can be determined from equation (1). The pushed gas Q ₁ that has flowed into the pipe is the difference between the measured value F ₁ by the flow meter 9 and the measured value F ₂ by the flow meter 17 . It is convenient to use a mass flowmeter as the flowmeters 9 and 17 because it is not affected by the temperature of the gas. Here, 1 ₁ is the resin plug position at time T ₁ ,
P ₀ is the measured value of the pressure gauge 10, P ₁ is the measured value of the pressure gauge 8, and d is the inner diameter of the lining in the existing pipe 1. Next, in order to detect the flow rate of the resin plug, the air supply was stopped for a certain period of time (t seconds), and the pressure gauge
If we measure the change in pressure inside the pipe P ₁ → P ₂ and set the resin plug position at this time to 1 ₂ , then 1 ₁・P ₁ = 1 ₂・P ₂ , and if we know P ₂ , after a certain time t seconds. Resin plug position 1 ₂
You can know. Therefore, the flow rate V of the resin plug is V=1 ₂ −1 ₁ /t. In addition, if the air supply is not stopped and the constant inflow in the previous state is continued, the inflow amount Q ₂ of the pushing gas at a certain time T ₂ and the pressure P ₂ inside the pipe are measured, and π/4・d ²・From 1 ₂ · P ₂ = Q ₂ · P ₀ , 1 ₂ = Q ₂ · P ₀ /π/4 · d ² · P ₂ , and the resin plug flow velocity V is V = 1 ₂ −1 ₁ /T ₂ − It becomes T ₁ . In this way, the arithmetic unit 6' and the control device 6 control the flow rate adjustment valve 11 (R ₁ ) and the flow rate adjustment valve 16 (R ₂ ) so that the resin plug flow rate V becomes constant. In this way, the resin A is filled in a predetermined length from the launcher 2 connected to the injection side pipe end of the existing pipe 1 so as to fill and block a predetermined length of the pipe in a liquid state, and the resin A flows into the resin plug A. The pressure of the pushing gas that imparts properties is determined by the flow velocity in the pipe, the resin plug position obtained by measuring the mass flow rate of the pushing gas at the starting end of the pipe and the pressure in the pipe, and the resin plug position measured at predetermined time intervals. The amount of pushing gas inside the pipe is controlled so as to keep the resin plug speed calculated from the difference between be done. On the other hand, in the repair work of the present invention, the amount of resin plug A filled (introduced) into the pipe so that a predetermined flow rate of the resin plug can be obtained by the pressing force, and the length of the coating film formed by the amount of resin plug for one time. If the length of the existing piping 1 to be repaired is long, due to limitations in the repair process, it is necessary to perform the repair in parts by repeating filling and flowing the resin plug A multiple times according to the length. , This makes it possible to increase and extend the length of the repair section as desired. In addition, by limiting the filling amount of the resin plug in the pipe to a predetermined amount, the pushing gas pressure of the resin plug can be reduced.
It becomes possible to suppress the pressure to a low level, and as a result, even if there is a corrosion hole in the repaired pipe, good lining can be performed without causing a blow-through. In addition, in the repair work according to the present invention, if there is a large corrosion hole in the middle of the existing pipe 1 or if a branch pipe with an unclosed valve is connected, immediately after the resin plug passes, the forced gas may blow through from there, causing a sudden decrease in the pressing force, and the resin plug A may no longer flow. In this case, the pressure gauge 8 and flow meter 9 in the control device 6 detect the blow-through gas flow rate per hour, and the flow rate is added to maintain the pushing speed of the resin plug. It's getting old. In other words, when the above-mentioned blow-through of the pushing gas occurs, the corrected flow rate calculated from the mapped flow rate of the pushing gas before the blow-through and the flow rate of the blow-through gas per time is immediately applied to the pushing gas after the blow-through. The static pressure is increased to return to the original pushing speed and start the flow of the resin plug A again, and to keep the flow speed of the resin plug constant as the number of resin plugs moving in the pipe decreases. It is now possible to control the pressure.

【Effect of the invention】

As explained above, the lining repair method according to the present invention moves the resin plug at a constant speed by connecting a launcher equipped with a control device to control the gas flow rate of pressurized gas to the injection side pipe end of the existing pipe. control can be performed at the resin injection end side of the existing piping, and when the launcher part increases the initial pressing force that gives fluidity to the resin plug A introduced into the pipe, and when moving within the pipe (for example, 0.6 kg/cm ²
(Below) In response to the decrease in the amount of resin, the flow rate of the resin plug is attenuated by static pressure to keep it constant, and the residual resin plug when the resin plug flows forms a coating film on the inner surface of the tube. Since it is lined, the following effects can be obtained. (1) First, the amount of inflow of pushing gas introduced into the pipe,
A control device is installed at the resin injection end to calculate the resin plug position from the pipe internal pressure, calculate the flow velocity of the resin plug flowing in the pipe from the difference in the resin plug position at each predetermined time, and keep it constant. For example, even if there is a branch pipe or leakage point at the rear end of the existing pipe,
Constant speed flow control of the resin plug is possible without being affected by these factors. Furthermore, by making the pushing gas the same as the gas flowing on the main pipe side, it is also possible to repair, for example, gas pipes while the pipes are still live. (2) Next, when the resin plug is made to flow using the pressing force of static pressure, it can be freely controlled by selecting the flow speed of the resin plug and the resin viscosity, so the fluidity is imparted by the thixotropic property of the resin. After that, the resin plug undergoes a softening phenomenon and flows with a small pressing force (low pressure) and a small amount of air, which reliably prevents the phenomenon of blow-through from corrosion holes that occurs in conventional spray airflow methods. can do. Further, the blower used may be a baby compressor or a small cylinder, and the equipment can be significantly downsized. (3) Also, since it is possible to use a high-viscosity resin with thixotropy, the sagging phenomenon of the lining coating film can be reduced, and the pressing force that causes the resin plug to flow is uniform over the entire rear end surface. Therefore, it is possible to eliminate variations in film thickness such as being thinner on the upper surface side and thicker on the lower surface side of the tube, and to form a coating film with a uniform thickness in the circumferential direction of the tube.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view schematically showing an embodiment of the repair method according to the present invention, and FIGS. 2 and 3 are relationships between the resin plug pressing force when the resin plug flows and the film thickness and running speed according to the present invention. FIG. 3 is an explanatory diagram of the end face shape of the resin plug. 1... Existing piping, 2... Launcher, 4... Resin injector, 5... Solenoid on-off valve, 6... Control device, 6'... Arithmetic device, 7... Solenoid on-off valve, 8... Pressure gauge, 9... Flow meter, 10... Pressure gauge, 11...Flow rate adjustment valve, 12...Compressor, 13...Three-way switching valve, 14...Flow rate adjustment valve, 15...Pressure sliding plate, 16...Flow adjustment valve, 17
...Flowmeter, A...Lining resin (resin plug).

Claims (1)

[Scope of Claims] 1. A fluid resin is injected into a construction pipe to be repaired from an opening at one end in the form of a plug over a required length so as to close the inside of the pipe, and the resin plug is pre-filled with a diameter of the pipe. In the pipe inner lining repair method, which is made to flow at a set speed necessary to form the target lining film thickness based on the resin viscosity and other related conditions, at the injection side pipe end of the resin plug, inside the pipe. A launcher having a control device for controlling the gas flow rate of the forced gas introduced into the pipe is connected, and the control device measures the flow rate of the forced gas introduced into the pipe and the pressure inside the pipe to determine the position of the resin plug in the pipe. and means for intermittently detecting the position of the resin plug and detecting the resin flow speed from the difference in the resin plug position at predetermined time intervals, and the resin flow speed is kept constant via the control device. 1. A method for controlling resin pressing pressure in a pipe inner lining repair method, characterized by controlling the pressure of pressing gas in a pipe so as to