JPS61125475A - Method for lining inner wall of pipe - Google Patents

Abstract

PURPOSE:To form a lining coated film having desired thickness on the inner wall surface of a pipe by keeping the air pressure on the inlet side of the pipe to be treated constant during the lining treatment, and regulating the flow rate of air discharged from the end of the pipe to the flow rate value which is previously set in accordance with the thickness of the coated film. CONSTITUTION:A fluid mixture of an epoxy resin paint and air is supplied to the inlet end of a pipe 13 to be treated, the paint layer deposited on the inner wall surface of the pipe is successively moved forward by the airflow, and a coated film is formed on the inner wall surface of the pipe. In this method, the pressure on the inlet side of the pipe 13 to be treated is kept by a regulator 18 at an appropriate set value during the lining treatment, and the flow rate of air discharged from the pipe end by a constant flow valve 22 connected to the terminal end of the pipe 13 to be treated is regulated to a flow rate value which is previously set in accordance with the thickness of a coated film to be formed in the pipe during the lining treatment. A lining coated film having desired thickness is thus formed on the inner surface of the pipe. Consequently, the lining efficiency can be remarkably improved.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an improvement in a lining construction method that is applied after grinding the scale of buried pipes such as water pipes and equipment pipes, etc. The present invention also relates to a method for lining pipe inner walls, which enables accurate control as desired and greatly improves work efficiency.

(Prior Art) The applicant previously applied a mixed fluid of a two-component epoxy resin paint and compressed air to the pipe line to be treated as a means of protecting the inner wall surface of the pipe after grinding of scale, etc. JP-A-55-39 describes a technique for forming a lining film of a constant thickness on the inner wall surface of the pipe by pumping it into the pipe from one end and causing the paint layer that adheres to the inner wall of the inlet end of the pipe to sequentially flow forward.
It is published as issue 274.

In addition, the applicant has proposed a technique as shown in FIG. 2 as a method for controlling the paint film thickness in the above-mentioned lining method in Japanese Unexamined Patent Publication No. 57-1.
It is published as No. 05271. That is, an accelerator 2 and a mixing nozzle 4 having a paint ejection tube 3 with an inner diameter of 2 are connected to the proximal end of the to-be-treated material whose internal temperature is 2, and first, the accelerator 2 and the nozzle 4 are injected into the accelerator 2 and the nozzle 4, respectively. In addition to supplying the accelerating air flow A and the mixing air flow B of the same pressure, the valves 5 and 6 are adjusted so that the air flow speeds in the treated pipe 1 and the paint jet 93 are approximately the same. Adjust flows JiF+ and Fz of flows A and B.

Next, when the lining film thickness of the pipe to be treated 1 is set to d, the opening degree of the paint adjustment valve 7 is adjusted so that the flow 3 + Fz of the mixing air flow B is equal to 1 mz of the initial setting value F2. -2 d Adjust the supply amount of paint C so that it is twice as large as the stone omitted (□). After that, the opening degree of the valve 7 is adjusted, and the F! The air flows A and B and the paint C are continued to be supplied while maintaining the same at a predetermined value until the paint layer flows out from the end of the tube 1 to be treated. In FIG. 1, 8 is a paint mixer, 9 is an epoxy resin paint supply device, 10.11 is a flow meter, and 12 is a compressor.゛The technique according to the above-mentioned Japanese Patent Application Laid-Open No. 57-105271 is that when the air flow velocity V+ in the treated object 'l1F1 and the air flow velocity V in the paint supply pipe 3 are equal, the air flow velocity d2 is formed on the inner wall surface of each pipe.
It was developed on the premise that the coating thickness d in the large-diameter treated tube 1 is expanded to the coating thickness in the small-diameter paint ejection tube 3, and this is expanded. Flow meter 1
1 (air flow B), it is possible to control the film thickness in a very precise manner. However, there remains a persistent problem in adjusting the paint flow rate.

That is, the epoxy four-finger paint used in this type of lining has a high viscosity of about 6,000 cps, so that a layer of paint often sticks to the valve seat and valve body of the flow 1 regulating valve 7. As a result, the effective cross-sectional area of the valve 7 changes, making it extremely difficult to accurately control the paint flow by adjusting the valve opening. Therefore, as the paint layer flows forward and a lining desert is formed, the air resistance of the pipe increases, and as a result, the air pressure at the inlet end of the pipe to be treated 1 increases. As a result, the flow velocity V+ of the accelerated air inflow decreases.

This is because the air flow velocity vt in the pipe increases in inverse proportion to the absolute pressure when the pipe diameter and air supply ball are constant. Therefore, when the pipe length of the pipe to be treated 1 is relatively short and the diameter is large, this problem does not occur, but in the case of a pipe with a small diameter and a long length, the inlet end of the pipe to be treated w1 The paint layer supplied to the tube and deposited on the inner wall surface does not flow forward smoothly and at an even speed, resulting in a large difference in MA thickness between the inlet and outlet sides of the tube 1, or In some cases, paint may drip or in extreme cases,
This method has the disadvantage of causing paint clogging.

Because of the above-mentioned gap 1, in actual construction, in order to equalize the film thickness on the inlet side and outlet side of the pipe to be treated 1, and to finish the film thickness itself,
After the paint layer flows out from the outlet side and the supply of paint C is stopped, the film thickness is adjusted by continuing to flow constant miscarriage of film thickness adjustment air. That is, before starting lining, a predetermined flow rate jlQs of film thickness adjustment air is flowed into the pipe to be treated 1, the supply air pressure PI at that time is measured, and after stopping the supply of the paint C, the predetermined flow rate O3 and The film thickness adjustment air flow from the wholesaler is continuously supplied, and the film thickness adjustment air flow is stopped when the ratio (-) between the current supply air pressure P2 and the air pressure P1 reaches a predetermined value. . That is, the coating material 1 on the inner wall of the tube is entirely pushed out by the film thickness adjusting air flow QS, and the P2 gradually decreases with the passage of time. As a result, if conditioning air is flown for a long time (
When Pt/Pt is small), the film thickness is adjusted to be thin, and when airflow is made to flow for a short time (Pi/Pt is large), the film thickness is adjusted to be thick.

However, such work with a film thickness of 1 m is time-consuming, and once the paint begins to harden, the a thickness cannot be adjusted sufficiently, which further increases the amount of wasted paint.

The present invention is intended to solve the above-mentioned problems in the conventional method of lining the inner wall of a pipe. You can control the film thickness without having to do it separately.
Moreover, it is an object of the present invention to provide a method for lining the inner wall of a pipe, which makes it possible to form a lining coating film having a uniform thickness without unevenness.

(Means for Solving the Problems) The present invention supplies a mixed fluid of epoxy resin paint and air to the inlet end of a pipe to be treated, and sequentially spreads four material layers adhered to the inner wall surface of the pipe by the air flow. In a pipe inner wall lining method in which a coating film is formed on the pipe inner wall surface by flowing the fluid forward, the pressure on the inlet side of the treated object is kept constant by a regulator during the lining process, and the A constant flow source valve connected to the end of the processing pipe is used to control the flow of air released from the end of the pipe to a preset flow Mk according to the thickness of the coating film to be formed in the pipe during lining processing, The basic structure is to maintain the air flow velocity within the pipe to be treated at a substantially predetermined level over the entire length of the pipe.

(Function) The pressure at the inlet end of the pipe to be treated is always maintained at a predetermined set value by the regulator during the relining process, and the flow rate of air flowing inside the pipe is also maintained at the end of the pipe to be treated during the lining process. The preset constant flow rate is directly maintained by one constant flow valve connected to the pipe.As a result, even as the lining of the pipe inner wall progresses, the air flow velocity at the pipe inlet end remains substantially constant. The paint layer mixed in at a constant flow rate from the paint supply device and deposited on the inner wall surface of the pipe inlet is constantly swept away at a constant speed along the inner wall surface of the pipe with a constant dynamic pressure. On the other hand, the paint film As the formation progresses, the resistance of the pipe increases and the pressure drops at the end of the pipe.Thus, the flow rate of air released from the end of the pipe gradually decreases, but the opening degree of constant flow valve 1 is automatically adjusted in the opening direction. This reduces the resistance of the pipe system, and the flow rate of air discharged from the end of the pipe is maintained at a substantially constant set value.As a result, the paint flowing forward along the inner wall surface of the pipe.
is swept away by an air flow of a substantially constant flow rate set in the fluid core crimping constant flow valve, and a coating film having a constant thickness corresponding to the set flow rate is formed.

Note that even if the pressure at the tube inlet end is always kept constant by the regulator, the pressure at the tube bed end will drop to a certain degree.

The air flow velocity at the end of the pickled fruit and tube bed is slightly higher than that at the Hiko inlet, and the hot water pressure acting on the paint layer changes. However, as mentioned above, the flowing paint layer has an extremely high viscosity, and the viscosity at the end of the pipe tends to increase over time. A coating film having a substantially constant thickness is formed over the entire length.

Furthermore, the present invention requires a regulator with a relatively large capacity, so it is not very suitable for lining large-diameter pipes.

(Fushi line) Figure 1 is an implementation system diagram of the present invention, and in the figure, 13
14 is an epoxy-resin co-forming device, 15 is a paint mixer, 16 is a paint regulating valve, 17 is a compressor, 18 is a regulator, 19
is an accelerator, 20 is an inlet pressure detector, 21 is a flow rate detector,
22 is a constant flow valve, T is a lining reservoir, and U is a purification device.

When lining the tube 13 to be treated, first the compressor 17 is activated, the regulator 18 and the inlet pressure detector 20 are adjusted, and the tube inlet pressure P1 is set to an appropriate pressure, for example, 4 to 8 kg/cd. By applying the input pressure sensor and setting and adjusting the regulator 18, the pipe inlet pressure P1 is maintained at approximately the set value during the lining process.

Next, the flow rate detector 21 and constant flow 1 valve 22 connected to the end of the pipe 13 to be treated are adjusted, and the air flow 1 flowing through the pipe 13 is adjusted.
is determined in advance according to the thickness of the coating film to be formed (direction, for example, 1.15 to 2.5 m' for diameter 1).
/ min, 6~lOm'/min for aperture I'
Set to a certain degree. Due to the settings of the detector 21 and the constant flow valve 22, a mixed fluid at approximately the set flow rate will flow in the pipe 13 during the lining process.

Incidentally, since the constant flow valve 22 is sequentially controlled in the opening direction as the lining of the inner wall surface of the pipe 13 progresses, the regulator 18 needs to have a considerable margin in flow rate characteristics. As a result, the present invention is unsuitable for lining large-diameter pipes with a diameter of a' or more, but is suitable for lining small-diameter pipes with a diameter of d' or less.

The relationship between the set flow m (Q) of the constant flow valve 22 and the lining film thickness 1) formed on the inner wall surface of the pipe 13 is determined in advance by determining the paint concentration (W) in the mixed fluid for each pipe diameter. ), paint viscosity (C), and temperature (T) as parameters, it is determined by actual measurement tests.

For example, is the paint concentration in the mixed fluid 20? r/ffr′,
When the paint viscosity C is 6000 CPS, the temperature T is 25°C1, the pipe diameter is 1, and the processing length is 70m, the mixed fluid flow rate. is 1
．． At 2 doors/min, the formed film thickness t is approximately 1.2 mm,
Also.

When ZOnf/mi is 11, the film thickness t is approximately 1.0.
+a.

Inlet pressure P1 and air flow rate of the tube to be treated 13. Once the setting is completed, the paint supply device 14 is moved α and the paint ': A regulating valve 16 is controlled to continuously supply a predetermined amount of two-component mold epoxy 211 grease coating with a predetermined viscosity into the accelerator 19. After the paint 25 and the air stream 26 are thoroughly mixed in the accelerator 19, they are ejected inward from the inlet end of the disposal tube 13. The paint particles in the mixed fluid injected into the pipe are sequentially stacked on the inner wall surface of the pipe inlet end, and the continuously ejected mixed fluid moves the paint 71 forward along the inner wall surface of the pipe at a substantially constant speed. Once the inner wall surface of the pipe is fluidly wetted by the paint, the subsequent paint layer flows on the wetted surface at a relatively high speed, catching up with the preceding paint layer and coalescing with it). A coating film is formed with a thickness that depends on the flow rate.

The thickness of the coating layer formed by - times of paint flow is approximately inversely proportional to the flow rate of the paint layer at the tip, that is, the advancing speed of the paint layer on the inner wall surface of the tube, and the slower the flow, the more The coating becomes thicker.

When the mixed fluid is supplied into the pipe for a certain period of time and one coat of paint flows out from the end of '113, the paint! ! After closing the air valve 16 and supplying only air flow for a certain period of time to discharge the residual paint inside the pipe, the air supply is stopped or the supply flow rate is lowered to remove the paint film formed on the inner wall surface of the pipe. dry.

(Effects) In the present invention, the paint film thickness is controlled by keeping the flow rate of paint supplied into the pipe to be treated constant and adjusting the flow rate of the paint layer deposited on the inner wall surface of the pipe. Therefore, there is no problem such as a decrease in accuracy when the paint adjustment valve becomes clogged.

In addition, in the present invention, the pipe inlet pressure and the flow rate of the mixed fluid in the pipe are set in advance and maintained directly, so the fluid flow velocity at the pipe inlet end hardly changes. figure,
As a result, unlike in the past, the paint lΔ does not drip at the pipe inlet end or the coating film becomes extremely thick at the pipe inlet end.

Furthermore, since the flow rate of the mixed fluid inside the pipe is maintained at a roughly set value during the lining process, the paint layer that builds up along the pipe's inner wall surface advances at a substantially constant set speed, and the entire surface of the pipe's inner wall surface is completely covered. It is possible to form a 1aiJJ having a uniform thickness over the entire area and a desired thickness.

Furthermore, by simply setting the flow rate of one constant flow valve, the thickness of the coating film formed on the inner wall surface of the pipe can be heated and accurately controlled, which is much easier than the conventional method of adjusting coating film thickness. This greatly improves lining work efficiency.

[Brief explanation of the drawing]

FIG. 1 is an implementation system diagram showing a first embodiment of the present invention. FIG. 2 is an explanatory diagram of the lining method according to Japanese Patent Application Laid-Open No. 57-105271. 13. He disposal tube 19 Accelerator 14 Paint supply bag @20 Population pressure detector 15 Mixer
21 Flow rate detector 16 Paint adjustment valve '22
Constant flow valve 17 Compressor Imperial order Lining number 18 Regulator 24 I-consolidation device patent applicant 3 Nishisha Japan Plant Service Center

Claims (1)

[Claims] A mixed fluid of epoxy resin paint and air is supplied to the inlet end of the pipe to be treated, and the paint layer adhered to the inner wall of the pipe is sequentially flowed forward by the air flow, thereby forming a coating film on the inner wall of the pipe. In the method for lining the inner wall of a pipe, the pressure on the inlet side of the pipe to be treated is maintained at an appropriate setting value during the lining process by a regulator, and the pressure on the inlet side of the pipe to be treated is maintained at an appropriate setting value during the lining process, and the pressure is maintained at an appropriate setting value by a constant flow valve connected to the end of the pipe to be treated. The flow rate of air released from the pipe end is controlled to a preset flow rate value according to the thickness of the coating film to be formed inside the pipe during the lining process, and a lining film of the desired thickness is formed on the inner wall surface of the pipe. A method for lining the inner wall of a small diameter pipe.