JPS5831987B2 - Lining method for pipe inner wall surface - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for lining the inner wall surface of a pipe after scale grinding treatment.

As a protection treatment for the inner wall surface of the pipe after scale grinding, a lining method is widely used in which a mixed gas of paint and air is blown into the end of the pipe to form a paint film of a certain thickness on the inner wall surface. It has been adopted.

The applicant has previously developed a new technology that can significantly reduce paint loss and reduce the amount of air required in the lining method described above, and has disclosed this technology in Japanese Patent Application No. 55-68703. It is published.

Fig. 1 shows the outline of the process, in which a mixed gas A of paint and air is injected from the injection nozzle 2 in the form of a hollow inverted cone onto the inner wall surface of the end of the pipe 3 to be treated. By pressurizing high-pressure air into the suction air ejector 4 disposed at one end of the tube 3 and sucking outside air, paint transfer air 5 is supplied into the tube 3, and a laminate 6 of paint particles adheres to the inner wall surface of the tube. It is configured to sequentially sweep forward.

Further, an exhaust air ejector 7 is provided at the end of the pipe 3 to forcibly exhaust the fluid inside the pipe, thereby smoothing the flow of the paint transfer air 5.

With the above configuration, the sprayed paint particles adhere evenly and strongly over the entire circumference of the inner wall of the pipe, preventing the paint adhering to the upper part of the inner wall of the pipe from dripping. The amount of paint particles that evaporate becomes almost zero,
Paint loss can be significantly reduced.

Furthermore, by using the air ejector 5.7, the required capacity of the high-pressure air source can be significantly reduced, and moreover, it is possible to form a paint film of uniform thickness with few spots on the inner wall surface of the tube.

However, the above technology still has some drawbacks.

That is, the initial flow of the paint layered body 6 by the air 5 for transporting the paint lacks smoothness, and therefore, if the mixed fluid A is incorrectly adjusted at the end of the work, the paint film at the inlet end may spread to other parts. The disadvantage is that it is easy to become a first-time user.

In addition, since the paint transfer air 5 is flowing parallel to the axis of the pipe 3 to be treated, there is a difference in the paint transfer force acting on the upper and lower inner wall surfaces of the pipe at curved parts of the pipe. As a result, there is a drawback that unevenness tends to occur in the thickness of the coating on the inner wall surface of the curved portion.

The present invention aims to eliminate the above-mentioned drawbacks of the above-mentioned Japanese Patent Application No. 55-68703, and aims to transform the air flow from the intake air ejector 4 into a swirling flow into the pipe 3 to be treated at high speed. Splashing out, or at the same time, mixed gas A
By giving swirlability to the pipe, the paint laminate 6 at the end of the pipe is diffused and given sufficient fluidity, and the coating thickness at the measuring part of the pipe can be formed more uniformly. The object of the present invention is to provide a method for lining the inner wall surface of a pipe.

Hereinafter, the details will be explained based on each embodiment of the present invention shown in FIGS. 2 to 6.

FIG. 2 shows an outline of the lining method according to the present invention, and FIG. 3 is a sectional view of a mixed gas injection nozzle used in this method.

Referring to FIGS. 2 and 3, an epoxy paint 8 and compressed air 9 from a compressor (not shown) are sufficiently mixed in a pressurized injection device 10, where a mixed gas A is formed. be done.

On the other hand, an intake air ejector 12 is disposed at the inlet side end of the pipe 11 to be treated, and the injection pipe 13 is inserted through the intake air ejector 12 from the pressure injection device 10 is provided protrudingly, and an injection nozzle 14 is fixed to the tip thereof.

The injection nozzle 14 is composed of a horn 14a and a conical guide body 14b, as shown in FIG. It is sprayed onto the inner wall of the pipe in the form of a shape.

Reference numeral 15 denotes a detection tube made of a transparent material connected to the end of the pipe 11 to be treated, and an exhaust air ejector 16 is fixed to the outlet side of the detection tube 15.

As shown in FIG. 2, the intake air ejector 12 has an annular air swirling chamber 12a formed in the center thereof, and an annular air jetting opening with an appropriate gap in the inner front corner of the air swirling chamber 12a. 12b is provided.

Further, a high-pressure air pressure inlet 17 is formed in the outer circumferential wall of the air swirling chamber 12a in a tangential direction thereof, and from the pressure inlet 17, 9 mm of high-pressure air 18 is air swirled from 4 to 10. It is press-fitted into the chamber 12a.

Next, the lining operation according to the invention will be explained.

A paint 8 formed by mixing a main liquid made of an epoxy resin and a curing agent is sprayed in a pressurized injection device 10 at a pressure of 200 to 220 kf/- by a lining operation (not shown), Here, it is mixed with compressed air 9 (3 to 6 kg/1 sA) from the compressor to create a mixed gas A.

The mixed gas A passes through the injection pipe 13 and is blown from the injection nozzle 14 onto the inner wall surface of the pipe in the form of a hollow inverted cone,
The paint particles in the mixed gas A adhere to the inner wall surface of the tube.

On the other hand, the high pressure air pressure inlet 1 of the intake air ejector 12
7, from a compressor (not shown) to 4 to 10. 1 high-pressure air 18 is blown.

The blown high-pressure air 18 swirls at high speed along the outer circumferential wall of the air swirling chamber 12a, and flows forward from the annular air outlet 12b as a swirling high-speed air flow 18a.

Also, at this time, the pressure on the ejector opening side decreases due to the flow velocity of the jetted high-speed swirling air 18a, and the outside air 19 is sucked into the ejector 12.

The sucked outside air 19 is combined with the high-speed air 18a to form a paint transfer air flow B, which is press-fitted into the pipe 11 to be treated while rotating.

In addition, a compressor (not shown) is connected to an exhaust air ejector 16 disposed at the end of the pipe 11 to be treated.
~10 h/- high pressure air 20 is supplied, and the flow rate of the high pressure air 20 reduces the pressure on the outlet side of the pipe to be treated 11, promoting the exhaust inside the pipe to be treated 11, and moving the swirling paint inside the pipe. The flow velocity of air flow B is kept approximately constant.

The paint in the mixed gas A adhering to the inner wall surface of the tube is sequentially swept forward while swirling by the high-speed air flow B that is blown in from the end of the tube while swirling, and approximately 0.5
A paint film with a thickness of 0.5 to ITMt is formed at a speed of ~1.5 m/min.

When the paint reaches the end of the pipe 11 to be treated, the completion of lining is known from the flow of paint in the transparent detection tube 15, and the supply of the mixed gas A is stopped.

FIG. 4 shows the second embodiment of the present invention, and shows the fifth embodiment.
This figure and FIG. 6 show the injection nozzle used for this purpose.

In this embodiment, not only the airflow B for transporting paint but also
The mixture/gas A discharged from the tip of the injection nozzle 21 is also configured to form a swirling flow.

That is, as shown in FIG. 5, the mixed gas A from the accelerating injection device 10 is injected into the nozzle 21 through the introduction pipe 21b attached at a constant angle α to the axis and in the tangential direction of the nozzle cover unit 21a. Rotational motion is applied inside the cover unit 21a, and the mixed gas A takes the form of a swirling hollow inverted cone, and is injected from its tip onto the inner wall surface of the pipe 11 to be treated. Go.

Reference numeral 21C is a guide body, and by adjusting the front and rear positions of the guide body 21C, the jetting angle of the mixed gas A is adjusted.

If the direction or jet angle adjustment is not necessary, the guide body 21
C can be omitted.

FIG. 6 shows another type of injection nozzle used in the second embodiment, in which the paint 5 is ejected from the nozzle 22 in the form of a spray.

On the other hand, high pressure air flows from the opening 23 into the nozzle cover integrated 24.
The paint 5 and the high-pressure air are sufficiently mixed within the nozzle cover 24, and are ejected forward in the shape of a rotating hollow inverted cone. .

Reference numeral 25 denotes a guide body that adjusts the spread angle of the mixed gas, and may be removed if angle adjustment is not required.

Since the present invention is configured as described above, it can exhibit many excellent effects as described below.

(1) Since the mixed gas A75 is ejected from the injection nozzle in the form of a hollow inverted cone, the paint particles have a motion component perpendicular to the pipe wall surface, making it extremely efficient. Adheres evenly and strongly throughout.

In addition, because the paint adhering to the inner wall of the pipe is swept away by the air flow for transporting the paint, it is possible that paint particles in the mixed gas will adhere to the outer surface of the paint that is being swept away and accumulate in layers, unlike in conventional methods. As a result, paint adhering to the upper part of the inner wall surface of the pipe does not drip downward at all.

Therefore, even a pipe with a large diameter and many bends can be lined with a uniform thickness.

(2) Since the paint adhering to the inner wall surface of the pipe is sequentially moved forward by the paint transporting air flow that does not contain paint particles, there are almost no paint particles in the exhaust gas, and as a result, Paint loss is significantly reduced.

Further, the after-treatment of the exhaust gas becomes significantly easier.

(3) By providing the exhaust air ejector, the flow velocity of the air for transporting the paint inside the pipe to be treated 11 can be kept substantially constant over the entire length of the pipe.

As a result, the flow rate of the paint becomes approximately constant, making it possible to form a paint film with a more uniform thickness.

(4) Since the air ejectors 12 and 16 are used to convert a small volume of high pressure air into a large volume of low pressure air, a large volume high pressure air source is required as in the previous construction method. This reduces construction equipment costs and significantly reduces transportation and other expenses.

(9 Air flow B for transporting paint supplied into the pipe 11 to be treated
By rotating the pipe, the paint laminate adhering to the inner wall surface of the pipe is diffused and the initial fluidity at the end of the pipe is increased, making it possible to form a film with a more uniform thickness over the entire length of the pipe.

(6) Even at curved parts of the pipe, by giving swirling properties to the air flow B for transporting the paint, the paint transport force becomes approximately uniform over the entire circumference of the inner wall surface of the pipe, and the coating thickness inside the pipe is reduced. It does not cause any spots on the skin.

If we show the -fU of the comparative experiment with the previous construction method, the inner wall surface of 200 m of 4B pipe has a thickness of 0.5 tran to 1 rr.
In the case of lining with a rm film, the conventional construction method requires that a mixed gas at a pressure of 5 to 6 @/- be injected into the pipe and passed at a rate of about 40 to 45 fn/rnin. Moreover, it is almost impossible to prevent unevenness of the coating film from occurring on the upper wall surface of the curved portion or on the supply side of the mixed gas.

As a result, in practice, with the conventional construction method, the lining method could not be applied to pipes of 4B or larger.

On the other hand, in the present invention, in order to line the inner wall surface of the pipe 4B under the same conditions as above to a coating thickness of 0.5 m++~hm++, high pressure is supplied to the accelerated injection device and both air ejectors. Air is 5kg/cr? It is sufficient to blow out air at a pressure of i at a rate of 10 to 15 rn'/miH, and the required amount of high pressure air can be reduced to 1/3 to 1/4.
It can be reduced to a certain extent.

In addition, the amount of paint required is approximately 40 times the amount of the conventional method, making it possible to significantly reduce the amount of paint used, and there is no possibility that the thickness of the paint film on the curved portion or on the mixed gas supply side will become non-uniform.

Furthermore, it is sufficiently workable even for pipe diameters of 4B or more, and can be applied to pipes with a maximum diameter of about 800A (32B).

As mentioned above, the present invention has extremely high practical utility.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a method of lining the inner wall surface of a pipe according to the previous application. FIG. 2 is a schematic diagram showing a first embodiment of the lining method according to the present invention, and FIG. 3 is a sectional view of an injection nozzle used in this method. FIG. 4 is a schematic diagram showing the second embodiment of the present invention, and FIG.
The figure is a perspective view of the injection nozzle used for this. FIG. 6 is a sectional view of another type of injection nozzle used in the second embodiment. A...Mixed gas, B...Air flow for transporting paint, 10.
... Pressurized injection device, 11... Pipe to be treated, 12...
・Intake air ejector 14... Injection nozzle, 16...
・Exhaust air ejector 118a...high speed air, 1
9...Outside air.

Claims (1)

[Claims] 1. A synthetic resin paint 8 is mixed with compressed air 9 to form a mixed fluid A, and the mixed fluid A is injected from one end of the pipe to be treated 11 in a hollow inverted conical shape toward the inner wall surface of the pipe, Outside air 19 is sucked in by the intake air ejector 12 provided behind the injection point of the mixed fluid A, and the drawn outside air 19 is mixed with the high-speed air 18a jetted out in a spiral shape from the intake air ejector 12. The swirling paint transfer air flow B is supplied into the pipe 11 to be treated, and from the other end of the pipe 11 to be treated is an air ejector 16 for exhaust.
A method of lining the inner wall of a pipe in which the fluid inside the pipe is forcibly discharged.