JPS6058274A - Method for lining pipe inner wall - Google Patents

Abstract

PURPOSE:To form a film with a uniform thickness to the inner surface of a pipe by certainly detect the position of the leading part of the formed film, in applying coating to the inner surface of the pipe by injecting a fluid mixture consisting of a paint and compressed air into the pipe, by monitoring the change in the coefficient of presure fluctuation of compressed air. CONSTITUTION:In applying coating to the inner surface of the branched pipe 8 separated from a main pipe 7 at a branch point O, an accelerator 9 is attached to the opening part provided to the appropriate position of the branched pipe 8. A compressor is operated to send compressed air 14 to the accelerator 9 along with a paint 15 and both components are mixed to form a fluid mixture 17 which is, in turn, injected into the branched pipe 8. The paint particles in compressed air are adhered to the inner surface of the branched pipe 8 to form a film 19 and a paint layer 18 advances. In this case, pressure in the branched pipe 8 is detected by a pressure gauge 11 and the coefficient of fluctuation thereof is recorded by an automatic recorder 12. Because coefficient of pressure fluctuation is abruptly changed when the leading end of the film 19 reaches the branch point O with the main pipe 7, the supply of the paint 15 and compressed air 14 is stopped through a control board 13 by the signal S from the recorder 12 to prevent the paint from flowing into the main pipe 7 and the film 19 with a unifrom thickness is formed only to the inner surface of the branched pipe 8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a pipe inner wall lining method using a mixed fluid of paint and compressed gas, and the progress of lining can be detected from changes in the pressure fluctuation rate of compressed gas. This invention relates to a pipe inner wall lining method.

As a rehabilitation method for buried water pipes, etc., a mixed fluid of abrasive material such as crushed sand and compressed air is jetted from one end of the pipe cut into appropriate lengths to abrade and remove scale on the inner wall of the pipe, and then paint and compressed water are removed. A widely used method is to inject a mixed fluid of air from one end of the pipe to line the inner wall of the pipe.
JP-A-55-114960, JP-A-55-39274
No. etc.).

The above-mentioned lining method is extremely excellent because it can quickly form a coating film with a uniform thickness without unevenness over the entire inner peripheral surface of the pipe, even if the pipe has a bend in the pipe with a diameter of 4B or less. This is a construction method that has been developed since then.

However, there are still many problems that need to be solved with this lining method. Among these, there is an urgent need to develop a technique that can accurately determine the progress position of the coating film that is successively formed inside the pipe, that is, the progress state of the lining. For example, water supply piping for buildings, condominiums, etc. usually has a piping system as shown in FIG. When lining this water supply pipe, if you try to line the branch pipe 1a and supply a mixed fluid A of paint and compressed gas from the end 11 of the branch pipe 1a, it will inevitably flow into the main pipe 1 unless you know exactly how the lining is progressing. This results in paint flowing B, or in the vicinity of the branch point 0 of the branch pipe, a portion C where no paint film is formed. If the paint flows into the main pipe 1, the paint will concentrate and stick to that part, causing various problems such as an increase in water flow resistance and concentrated stickiness of scale. Further, if a portion where the lining film is not formed remains, there will be problems such as accelerated rust formation.

In order to avoid the above-mentioned inconvenience, in the conventional lining method, as shown on the left side of FIG.
The root of a- is lc, 2c, 3c...---
- is cut and the main pipe 1 and each branch pipe are completely separated, and then each branch pipe is lined.

However, each branch pipe is cut and separated from the wood pipe before lining.
Reconnecting the lining after lining is extremely complicated, and there is a problem in that lining costs cannot be reduced.

The same applies to the lining of pipes with different diameters as shown in FIG. Is it necessary to keep the flow velocity (2) of the mixed fluid A substantially constant? Therefore, the operator accurately knows the state of coating film formation, that is, the advancing position of the leading part 6 of the coating film that is successively formed inside the tube, and at the same time when the leading part 6 reaches the tip 4a of the large diameter part 4, Is it necessary to adjust the flow rate of the mixed fluid A to a flow rate according to the pipe diameter of the large diameter portion 4?

However, in the current lining technology, the position of the leading edge 6 of the advancing coating film cannot be accurately detected, so the timing of adjusting the flow rate to the mixed fluid is determined based on intuition based on experience. As a result, there is a problem that unevenness tends to occur in the coating film thickness near the enlarged diameter portion.

The present invention aims to solve the above-mentioned problems in lining branch pipes branched from the main pipe, pipes with different diameters, etc. By accurately detecting the position of the pipe, only the inner wall surface of the branch pipe can be reliably lined without separating the branch pipe from the wood pipe, or even in the case of pipes with different diameters, the coating film can be coated with a uniform thickness without unevenness over the entire inner wall of the pipe. The object of the present invention is to provide a method for lining the inner wall of a pipe.

Based on many years of experience in constructing this type of lining, the inventor of the present application jets out a mixed fluid of paint and compressed gas from one end of the pipe, and creates a layer of paint that adheres to the inner wall surface of the pipe at the end of the pipe inlet.
In the method of sequentially forming a coating film on the inner wall surface of a pipe by causing the compressed gas to flow forward, if the diameter of the pipe to be treated is constant and the flow rate of the compressed air flow is constant, the beginning of the coating film is The pressure on the inlet side of the pipe to be treated always increases at a constant rate depending on the pipe diameter while the part is moving through the same pipe diameter, and when the top of the coating reaches a part with a different pipe diameter, the pressure increases I learned that the rate of increase in the amount of money changes immediately.

The present invention was developed based on the above-mentioned knowledge of the inventor of the present invention, and the paint and compressed gas are ejected from one end of the pipe to be treated into the pipe, and the paint layer adhered to the inner wall surface of the pipe is coated with the compressed gas. In a pipe inner wall lining method in which the compressed air is forced to flow forward and a coating film is formed on the pipe inner wall surface, the flow rate of compressed air supplied into the pipe is maintained at a constant flow rate value according to the pipe diameter, and the The basic configuration is to measure the pressure of the compressed gas during the lining process, detect the completion of lining from the change in the rate of pressure fluctuation (ττ), and then stop the supply of paint and adjust the compressed air flow. be.

The details will be explained based on an embodiment of the present invention shown in FIGS. 3 to 6 below.

FIG. 3 is a system diagram showing a case where a branch pipe branched from a main pipe is lined according to the present invention.

In the figure, 7 is the main pipe, 8 is a branch pipe branched from the main pipe, 9 is an accelerator, 10 is an air flow meter, 11 is a pressure gauge, 12 is an automatic pressure fluctuation rate recorder, 13 is a control panel, and 14 is a compression gas,
For example, compressed air is fed under pressure from a compressor (not shown), etc., and paint 15 is fed under pressure from a paint pump (not shown).

When lining the branch pipe 8, the appropriate length from the main pipe 7 varies depending on the pipe diameter of the branch pipe, for example, the pipe diameter is 50 mm.
In this case, an opening is provided at a point 80 to 100 m apart, and the accelerator 9 is attached here. Next, a compressor (not shown) is operated to adjust the air pressure to 2 to 51, and then compressed air 14 is sent to the accelerator 9 under pressure. The flow rate of the compressed air to be fed to the accelerator 9 is controlled by the flow rate adjustment valve 16 to a value of 1.5 to 2.5 N - 111/- when the pipe diameter of the branch pipe is IB.
4 B 2.3~3.9 ””/-tn, 11/2
B (D (!: Ki 3.4 ~ 5.6 ”/-t, 2
6 to 10 when B, 13 when ``In'/, t,, 3B
．． 5~22.5 ””/*=, 4 B] when 24~
40 Nm”/, * Initial setting, and after that, the flow rate adjustment valve 16
is automatically or manually controlled to maintain the flow rate of air supplied to the accelerator 9 at the above-mentioned constant value during the lining process.

Next, a paint pump (not shown) is started to supply a predetermined amount of paint 15, for example, a two-component mixed epoxy resin paint (or a mixed fluid of paint and air) to the accelerator 9. The paint 15 and the air flow 14 are mixed within.

The mixed fluid 17 of paint and air formed in the accelerator 9 is
The paint particles in the airflow are ejected inward from the open end of the branch pipe 8 and are successively deposited on the inner wall surface near the exit side of the accelerator 9, and the deposited paint layer 18 is ejected from the rear. The mixed fluid 17 is sequentially swept forward by the air flow in the mixed fluid 17, and a coating film 19 is formed on the inner wall surface of the pipe.

In this embodiment, after the paint and air flow are mixed in the accelerator 9, the mixed fluid 17 of both is discharged into the branch pipe 8. Of course, the flow j4 and the paint 15 may be jetted out separately.

Figure 4 shows the pressure fluctuation state of the pressure gauge 11 during lining. This is an example of a case where the supply air pressure is 2 degrees. That is, when the paint layer 18 sequentially flows forward in the branch pipe 8 and the paint film 19 is being sequentially formed on the inner wall surface of the pipe, ΔP. Then, the fluctuation rate α(□)Δt of the pressure P of the pressure gauge 11 is approximately constant, and the pressure P increases linearly as shown in the figure.

Then, when the paint layer 18 reaches the branch point O between the branch pipe 8 and the main pipe 7, the pressure fluctuation rate α changes rapidly.

In this embodiment, this sudden change in the pressure fluctuation rate α is detected and confirmed by the automatic recorder 12, and the paint 15 or the paint 15 and the compressed air 14 are controlled by the signal S from the automatic recorder 12 via the control panel 13. supply will be stopped.

By doing this, the branch pipe 8 is completely lined up to the branch point 0, and moreover, it is possible to almost completely prevent the paint from flowing into the main pipe 7 side.

Figure 5 is a system diagram for lining the different diameter pipe 20, and the construction method is the same as that for the branch pipe shown in Figure 3 above.

In this embodiment as well, while the paint layer 18 is flowing through the small diameter tube 21, the pressure P of the compressed air has a substantially constant pressure fluctuation rate a, as shown in FIG.

When the paint layer 18 reaches the boundary k with the large-diameter pipe 22, the pressure fluctuation rate α changes rapidly at that point, and this pressure fluctuation is detected and confirmed by the automatic recorder 12. When the automatic recorder 12 detects a sudden change in the pressure fluctuation rate α, the signal S is applied to the control panel 13 and adjusted via the control panel 13. As a result, the air flow velocity within the large diameter pipe 22 is adjusted to a predetermined value,
As a result, the flow rate of the paint layer 18 is also adjusted, and a paint film of uniform thickness is formed on the entire inner peripheral surface of the tube of different diameters.

As mentioned above, the present invention focuses on the relationship between the position of the flowing paint layer and the pressure fluctuation rate of the supplied gas when the supply flow rate of the compressed gas 14 for conveying the paint is constant, and changes in the pressure fluctuation rate. The lining is connected to the branch point 0 of the branch pipe 8 or the different diameter pipe 20.
When it is confirmed that the enlarged diameter section k of the paint is completed, the supply of paint is automatically stopped or the flow rate of the conveying air is adjusted.

As a result, even if you line a branch pipe while it is connected to the main pipe, there is no chance of a large amount of paint flowing into the main pipe or leaving unfinished areas of lining, and work efficiency is greatly improved. improves.

Furthermore, in the case of lining pipes with different diameters, it is possible to form a coating film that is free from unevenness and can almost completely prevent variations in coating thickness at the enlarged diameter portion.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of problems in the conventional lining method for water supply pipes in apartments and the like. FIG. 2 is an explanatory diagram of problems in the conventional lining method for pipes of different diameters. FIG. 3 is an explanatory diagram of lining a branch pipe according to the present invention. FIG. 4 is a diagram showing how the air flow supply pressure P changes in the first embodiment. FIG. 5 is an explanatory diagram of lining pipes with different diameters according to the present invention. FIG. 6 is a diagram showing how the air flow supply pressure P changes in the second embodiment. 7 Main pipe 8 Branch pipe 9 Accelerator] O flow meter 11 Pressure gauge 12 Pressure fluctuation rate automatic recorder 13 Control panel] 4 Compressed gas 15 Paint 16 Flow rate adjustment valve 17 Mixed fluid 18 Waste layer 19 Paint film 20 Different Diameter Pipe P Pressure Fig. 1 5 Fig. 2 Fig. 4 () () -1

Claims (1)

[Claims] Spray compressed gas (14) and paint (15) from one end of the tube 1
- A pipe inner wall lining method in which the paint layer (18) adhered and laminated on the pipe inner wall surface is made to flow forward by the compressed gas (14) to form a coating film on the pipe inner wall surface/i
: Maintaining the flow of the compressed gas (14) supplied into the pipe at a constant value according to the pipe diameter, and measuring the pressure (P) of the compressed gas (14) during the lining process,
A method for lining the inner wall of a pipe of a branch pipe or a pipe of different diameters branched from a main pipe, the method comprising detecting completion of lining from a change in the rate of variation (α) of the pressure (P).