JPS6044990B2 - pipe cleaning method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for grinding and cleaning the inner wall surface of a pipe such as a water supply pipe using a sand jet stream.

The applicant had previously developed a method for grinding and cleaning the scales of water supply pipes, etc. using a sand jet flow, and filed a patent application in 1983-11.
This is officially recognized as the 49 seal.

Figure 1 shows the outline of the compressor 1.
Pressurized air is introduced into the sand tank 3, mixing ejector 4, and sand accelerator 5 through the drain separator 2, and the sand flow 6 from the mixing ejector 4 is accelerated by the accelerator 5, and the sand flow is then washed. By injecting into the pipe 7, scale etc. stuck to the inner wall surface of the pipe 7 is ground. In FIG. 1, 8 is a regulator, 9 is a flow meter, 10 is a washing water supply device, and 11
is a sand collection device. However, the above-mentioned method has the following drawbacks.

That is, 1. Since the sand jet stream is injected straight forward from one end of the pipe 7 to be cleaned, if the pipe 7 is long, the sand will settle as the sand jet stream advances, and the inner wall surface of the pipe will be ground. tends to become uneven.

2. If the pipe 7 to be cleaned has a large diameter, a large capacity high pressure air source is required.

However, it is not easy to transport a large compressor to a construction site, and due to this, there are restrictions on the length and diameter of the pipe 7 to be cleaned at one time, making it difficult to significantly improve work efficiency. . In addition, if the pipe 7 to be cleaned has many curved parts, the sand jet flow will pulsate, easily causing sand clogging, and this also has the disadvantage that the length of one treatment is greatly limited. .

The present invention aims to eliminate the drawbacks of the above-mentioned Japanese Patent Application No. 53-11496, and can be used even with a large-diameter pipe with many bends and with a relatively small volume of high-pressure air. The object of the present invention is to provide a pipe cleaning method that enables uniform grinding and cleaning of the inner wall surface over a long distance.

Hereinafter, the details will be explained based on an embodiment of the present invention shown in FIGS. 2 to 4.

FIG. 2 shows an outline of the vibrator cleaning method according to the present invention, and in the figure, 12 is a sand accelerator, 13 is an intake air ejector, 14 is a sand injection nozzle, 1
5 is a vibrator to be cleaned, and 16 is an exhaust air sector.

The sand accelerator 12 receives a sand flow 17 (4 to 6
The speed of the sand flow 18 is increased by compressed air from a compressor (not shown), and the sand flow 18 accelerated by the accelerator 12 passes through the injection pipe 19 and enters the vibrator 15 to be cleaned from the nozzle 14. It is starting to be sprayed.

As shown in FIG. 2, the intake air sector 13 has an annular air swirling chamber 13a disposed in its center, and the air swirling chamber 13a is entered through a high-pressure air inlet 13b on the outer peripheral wall. High pressure compressed air is fed in the tangential direction.

An annular air outlet 13c is formed in the front corner of the air swirling chamber 13a, and the air press-ined from the high-pressure air injection row 13b swirls at a sufficiently high speed within the air swirling chamber 13a. It becomes a swirling flow and is injected forward from the jet port 13c. The exhaust air sector 16 is formed by protruding an air injection nozzle 16a outward from the center of the conically narrowed main body. High pressure air is supplied.

3 and 4 are examples of sand injection nozzles,
In the nozzle shown in Figure 3, the sand flow 18 is HO! - By passing between the tube 14a and the guide body 14b, it becomes a hollow inverted conical shape and is sprayed onto the inner wall surface of the vibrator.

In the nozzle shown in FIG. 4, the sand flow 18 is jetted into the cylindrical horn 14c in three directions tangential to the outer peripheral wall of the horn and fixed at a constant inclination angle a to the axis. It is ejected through the pipe 14d, and the high-speed sand flow 18 is discharged forward in the shape of a swirling hollow inverted cone.

In this embodiment, the sand flow 18 is formed into a hollow inverted conical shape and is injected into the pipe interior, but it is also possible to eject it in an inverted conical shape over the entire area of the pipe cross section. Of course.
Next, the grinding process for scales and the like according to the present invention will be explained. First, run the compressor and make approximately 1~5k9/
With a conveying pressure of cl, the mixing ratio of silica sand (No. 4 to 6) is 0.5 to 2.
The sand flow 17 adjusted to k9/Nd is transferred to the sand accelerator 1.
Supply to 2.

At the same time, high-pressure air 20 of about 4 to 10 kg/Clt is supplied to the sand accelerator 12 to accelerate the sand flow 17 and form a high-speed sand flow 18. Next, the high-speed sand flow 18 is injected from the sand injection nozzle 14, and high-pressure air of 4 to 10 k9/Clt is supplied to the intake air ejector 13 and the exhaust air ejector 16.

As described above, the high-pressure air supplied to the intake air ejector 13 becomes a swirling flow and is ejected into the vibrator 15 to be cleaned from the air ejection port 13c. Moreover, the pressure on the ejector opening side decreases due to the flow rate of the high-pressure air jetted out, and the outside air 21 is sucked into the working sector 13. The sucked outside air 21 is sent into the vibrator 15 to be cleaned while rotating together with the blower, and becomes an air flow for conveying the sand flow 18 . On the other hand, high-pressure air is supplied to the exhaust air sector 16, and the high-speed air flow jetted from the jet nozzle 16a lowers the pressure on the outlet side of the vibrator 15 to be cleaned, promoting forced exhaust inside the vibrator 15. Ru.

The high-speed sand flow 18 injected into the vibrator 15 is swirled by the conveying air flow 22 that is swirled and press-in from the rear of the nozzle 14, and is rotated at approximately 100 rT1/ Proceed forward at a speed of Sec.

At this time, it is more convenient to spray the sand flow 18 itself from the nozzle 14 in a swirling manner. The flow rate of the high-speed sand flow 18 injected into the vibrator 15 to be cleaned is adjusted according to the diameter of the pipe, and is usually set within the range shown in the table below.

According to the experimental example, when the sand mixing ratio is 1k9/Nd, 1B is 3d/Minlll and 4B is 4.7r.
r1/Mjnllll2B is 6.87T1/Min.
．． 2B has 12d/Mjn, and ? So 27d/Mjn
Optimal cleaning performance can be obtained when the flow rate is set to .

Sand flow flowing out from the end of the vibrator 15 to be cleaned! for,
3 to 5'/Min before introducing it to the sand collection device 11
- A spray of water is added, where deceleration by humidification takes place. The humidified sand stream is separated into solid matter such as sand and scale and air stream in the sand recovery device 11,
One collection of solids is performed. Although it varies depending on the thickness of scale fixed inside the pipe, the sand jet flow 23 is usually
By flowing the powder, the scale is completely ground and the inner wall surface of the tube is ground and cleaned until the specular reflectance reaches approximately 80%.

Furthermore, the end of grinding can be easily detected by the color of the sand being discharged. In the above-described embodiments, air flow is used as the transport fluid, but it is of course possible to use an inert gas such as nitrogen gas instead.

Since the present invention has the above-described configuration, it has many excellent effects as described below. (1) Since the sand jet flow flowing inside the vibrator to be cleaned is given a rotational motion to create a swirling flow, the sand and the air flow are not easily separated, and even if the vibrator to be cleaned 15 is long, the sand does not settle.

As a result, the inner wall surface of the vibrator can be ground and cleaned more uniformly, and the distance of one turning operation can be extended. (2)
By using intake air engineering sectors 13 and 16, a small volume of high-pressure air is converted into a large volume of low-pressure air, so a large-capacity high-pressure air source is required as in the previous construction method. Therefore, the cost of construction equipment and transportation costs can be significantly reduced.

(3) Exhaust air sector at the end of the vibrator 15 to be cleaned.
16 to forcefully exhaust the inside of the vibrator 15, the flow velocity of the sand jet flow 23 inside the tube becomes approximately constant, allowing scale grinding without unevenness, and even in a narrow tube, sand clogging does not occur. .

Generally speaking, in the case of conventional construction methods, which type of vibrator is being cleaned? In the case of , the distance that can be constructed at one time is approximately 100m, and ? In the case of , it is approximately 150771. It is.

On the other hand, in the case of the present invention, if the capacity of the compressor is the same, what is the possible construction distance? 20 in
0~2507TL. ．． 3B, it can be extended to about 300 to 350 m, and it is possible to appropriately grind irregularities even at curved parts. Also, if the distance and work time for one cleaning are constant, the amount of compressed air supplied from the compressor should be approximately 1
It becomes possible to reduce it to 12-112.5.

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

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a conventional vibrator cleaning method using a sand jet flow. FIG. 2 is a schematic diagram showing a vibrator cleaning method according to the present invention, and FIG. 3 is a sectional view of a sand injection nozzle. Fourth
The figure is a perspective view showing another example of the sand injection nozzle.
12...Sand accelerator, 13...Intake air engineering sector, 14...Sand injection nozzle, 15...Vibe to be cleaned, 16... ...Exhaust air engineering sector, 17...Sand style, 18
...High speed sand flow, 21...Outside air, 22
... Conveying air flow, 23... Sand jet flow.

Claims (1)

[Claims] 1. A high-speed sand flow 18, which is a mixture of silica sand and air, is injected inward from one end of the lined pipe 15, and intake air is provided behind the injection point of the sand flow 18. An ejector 13 is provided to suction the outside air 23 by ejecting a swirling high-speed air flow to the pipe 15 to be cleaned.
A sand conveying air flow 22 is supplied into the cleaning pipe 15, and an exhaust air ejector 16 is disposed at the end of the pipe 15 to forcibly discharge the sand jet flow 23 inside the pipe. How to clean pipes. 2. The pipe cleaning method according to claim 1, wherein the high-speed sand flow 18, which is a mixture of silica sand and air, is injected in the form of a swirling hollow inverted cone.