JPS61242680A - Method for washing pipe interior - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for cleaning the inside of a pipe. The present invention relates to a cleaning method in which a sweeper having a cutting blade embedded therein can be used.

[Conventional technology]

Many factories, such as chemical factories and steel factories, use various piping equipment to transport fluids such as liquids and gases. Such piping equipment is constructed as a pipeline connecting pipes of various shapes, but as the pipes are used, foreign matter such as scale adheres and accumulates inside the pipes. As such foreign matter accumulates inside the pipe, the resistance inside the pipe increases, reducing fluid transport efficiency and increasing the strain placed on the pump used to transport the fluid. It's coming.

In order to eliminate these harmful effects, it is necessary to perform periodic cleaning work on the pipeline, but in particular, decoking treatment is performed to remove foreign substances such as scale that are firmly attached to the inner wall of the pipe. ing. This decoking process involves blowing a large number of small iron balls or sand grains into the pipe using high-pressure nitrogen gas to scrape off foreign matter stuck to the inner wall of the pipe, or using rotating blades. There are methods such as sending a mechanical cleaner into the pipe and using the blades to scrape out foreign matter, and chemical methods such as flowing a solvent or the like into the pipe. However, these methods have drawbacks in that the cleaning effect weakens as the total length of the pipeline increases, and the cleaning effect tends to be uneven for curved pipelines.

For these reasons, in recent decoking processes, a sweeper is used, which consists of a cylindrical base made of foamed plastic with an outer diameter slightly larger than the inner diameter of the pipe, and a number of cutting blades embedded in the outer periphery of the base. - has been widely used, and has been very effective.

The sweeper travels inside the pipe while being forcibly contracted by a high-pressure water stream applied from behind, and in the process of this travel, the cutting blade scrapes off foreign matter stuck inside the pipe.

Moreover, since the sweeper can be bent in the direction of travel due to its own elasticity, it can be moved even in curved sections of the pipeline.

Therefore, if the inner diameter of the pipeline is kept almost constant over its entire length, it will be possible to move the pipeline freely back and forth. There is also the advantage that it can be washed in a vacuum.

By the way, when using the above-mentioned sweeper, it is necessary that the pipe has a circular cross section and an approximately constant inner diameter. However, some pipelines used in heating furnaces such as oil refineries and power plants have individual pipes connected to each other by return vents. In addition to simply connecting the pipes in a fluid-tight manner, this return bend also serves to agitate the flow of fluid sent from one pipe and send it to the other pipe. .

In other words, in pipelines used in heating furnaces, the temperature of the fluid flowing on the side of the pipe facing the heat source is higher than the temperature of the fluid flowing on the other side, so the return vent reduces the temperature inside the pipe. By stirring the flow of fluid in the pipe, the temperature distribution of the fluid in the pipe can be maintained almost uniformly.

For this reason, a flow path deflecting plug is attached to the return vent in order to twist the flow of fluid sent from one pipe to the other pipe. The fluid whose flow is changed by this plug is sent to the other pipe through a flow path formed in the return vent and having an elliptical cross section.

[Problems to be Solved by the Invention] However, as described above, the return vent, in which the cross section of the flow path formed inside is elliptical, or the fluid receiver of the plug incorporated therein, has a surface that is In pipelines using return bends that are not spherical,
A disadvantage is that the sweeper cannot be used to remove scale stuck to the inner wall of the pipe. In other words, since the sweeper is moved inside the pipe by water pressure applied from behind, the outer periphery of the sweeper and the inner wall of the pipe must rub against each other in a constant relationship. However, if the cross section of the flow path through which the sweeper runs is not circular, the high-pressure water flow for running the sweeper will flow from the excess gap created between the flow path and the outer circumference of the sweeper. They will run away and the sweeper will not be able to move forward efficiently.

The present invention was made in view of the above-mentioned technical background, and
Even if the pipe is connected via a return bend,
It is an object of the present invention to provide a method for cleaning the inside of a pipe in which decoking treatment using a sweeper can be performed continuously without separating these from the return bend.

[Failure to solve the problem]

In order to achieve the above object, the present invention removes a flow path deflection plug that is attached to and detached from the body of a return bend, and then connects both pipes connected to the body with a connecting pipe having a circular cross section. This is to provide fluid-tight communication. A sweeper for removing foreign matter that has passed through one pipe connected to the body can continuously pass through the connecting pipe to the other pipe. By attaching the connecting pipe to the body of the return bend, the flow path formed in the body is closed, and as a result, the two pipes connected to the body of the return bend are
Communication is established via a connecting pipe with a circular cross section, bypassing the flow path within the body.

Examples of the sweeper used to clean the pipe include the above-mentioned sweeper, which consists of an elastic cylindrical base made of foamed plastic material and a cutting blade embedded in the outer periphery of the base. Various types of vehicles are available that provide driving force using fluid pressure. The above-mentioned cleaning method also applies to a large number of pipes that are sequentially connected via return bends, by attaching the connecting pipe instead of a plug to each return bend. It is possible to run the pipe continuously over several pipes.

Embodiments of the present invention will be described below with reference to the attached drawings.

〔Example〕

In FIG. 4 showing an example of a pipeline to which the present invention is applied, the pipeline 1 in operation is a straight pipe 2.
are arranged in parallel, and one end of each of the adjacent pipes 2 is connected by an H-shaped return bend 3. The fluid sent from one end 1a of the pipeline 1 formed by a short pipe 30, which will be described later, is transferred to the pipe 2,
While sequentially passing through the 11 type return hend 3, the other end 1
sent to b.

As shown in FIG. 5, the 11-type return hend 3 includes a body 8 consisting of a cylindrical portion 5.6 and a connecting portion 7 therebetween, and a plug 9.1 attached to the body 8.
It is composed of 0. The plug 9 changes the flow of fluid sent from the bottom to the top in the pipe 2a, and connects the connection part 7.
The liquid is fed into the pipe 2b through the channel 7a, which has an elliptical cross section, and the other plug 10. Therefore, the socket of the plug 9 is on the surface 11, and the socket of the plug 10 is on the surface 1.
2 is formed into a twisted hemispherical shape.

The protrusion 13 integrally formed on the plug 9 is connected to the cylindrical portion 5.
The receiver is adapted to position the surface 11 by fitting into a slot 15 provided at the upper end of the holder. In order to secure the plug 9 to the cylindrical portion 5, a tightening seat 17 having an internal thread 16 and a bolt 18 are used. That is, an opening 20. which is formed penetrating the wall surface of the cylindrical portion 5.
21, a protrusion 17 integrated with the tightening seat 17;
When the bolt 18 is inserted into the female thread 16 and the bolt 18 is tightened, the tip of the bolt 18 enters the bottomed hole 9a formed on the top surface of the plug 9 and presses against the bottom surface of the plug 9.

The protrusion 17a of the tightening seat 17 is connected to the opening 20.2.
By tightening the bolt 18 until it is pressed against the upper end of the plug 9, the plug 9 is firmly fixed to the cylindrical part 5. Note that the plug 9 is formed with a tapered fitting surface 22, and this fitting surface 22 is pressed against a fitting surface formed corresponding to the inner wall of the cylindrical portion 5, so that fluid is discharged from between them. prevents it from leaking.

'' When two pipelines 1 are used in succession,
Foreign matter accumulates in the pipeline 1 depending on the type of fluid passed therein. For example, when the pipeline 1 is used in a heating furnace of an oil refinery plant, scale 25 mainly composed of carbon and iron sulfide adheres strongly to the pipe walls of the pipeline 1 at various locations and becomes laminated. If the inside of the pipe becomes blocked by such scale 25, the efficiency of the heating furnace will decrease and the temperature of the pipe wall of the pipeline 1 may rise abnormally, creating a dangerous situation. Decoking processing will be performed.

When performing the most effective decoking process, that is, the decoking process using a sweeper in which a large number of cutting blades are embedded in the outer periphery of an elastic cylindrical base, as described above. As shown in FIG. 1, a type II sole return bend 3 connected to the pipes 2a and 2b
After removing plugs 9 and 10 from pipe 2a,
, 2b are respectively attached to the cylindrical portions 5.6.

The short pipe 30 has four arms 32 integrally formed with through holes 32a so as to equally divide the outer periphery of the short pipe 30.
I'm getting fucked. Further, a set ring 36 in which four bolts 35 are implanted is attached so as to surround the upper part of the cylindrical portion 5. The set ring 36 can be separated by removing the bolt 37. Protrusions 38 and 39 that fit into openings 20 and 21 formed in the cylindrical portion 5 are formed at two locations on the inner wall of the seven-node ring 36 . Therefore, the protrusion 38, 39 is connected to the opening 2 (1,
21 and then each time the bolt 37 is tightened, the centering ring 36 is positioned and held in the cylindrical portion 5.

After attaching the centering ring 36 to the cylindrical part 5,
0 from above the cylindrical portion 5, and the bolt 35 is inserted into the through hole 32a formed in the arm 32. After that,
By screwing the navels 1 to 40 onto the bolt 35, the protrusions 38 and 39 of the centering ring 36 open 2"0.
The tip 30a of the short tube 30 is pressed against the upper end of the pipe 21, and using this as a counter, the tip 30a of the short tube 30 is pressed against the end of the pipe 2a connected to the H-shaped turn hend 3. As shown in FIG. 2, the tip 30a of the short tube 30 is provided with a gasket 42 made of rubber, for example, so that the tip 3'Oa of the short tube 30 and the end of the pipe 2a are connected. are fluid-tightly connected. Note that, similarly, a short pipe 30 is connected to the cylinder i6 instead of the plug 10. In addition, for pipes such as the pipe 2b in Fig. 2 whose ends are expanded by force, the tip end 30''b of the short pipe 30 is tapered and an O-ring 43 is provided around its outer circumference. Just leave it there.

Note that the raised portion 33 provided on the outer periphery of the short tube 30 slides against the inner wall of the cylindrical portion 5 and performs a guiding action when the short tube 30 is inserted into the cylindrical portion 5.

When the short pipes 30 are attached to the body 8 of the H-type return bend 3 in this way, the respective ends of the pipes 2a and 2b and the respective tips 30a and 3 of the short pipes 30
0b are fluid-tightly connected, and the flow path 7a formed in the cylindrical portion 7 is disabled. An elbow (U-shaped pipe) 45 having the same inner diameter as the short pipe 30 is connected via a flange 31 formed on the short pipe 30. As a result, the pipes 2a and 2b are short pipes 30. elbow
45, and will be communicated via the short pipe 30.

In this way, by connecting the pipes 2 connected via the H-shaped return bend 3 with the two short pipes 30 and the elbow 45, the cleaning pipeline shown in FIG. A receiving trap 50 is connected to one end of the pipeline 1'' via an intermediate pipe 46, a launcher 52 is connected to the other end via an intermediate pipe 46, and a pump 56, a water tank 57. A flow path shown by a solid line including a water challenge tank 58 is formed.A sweeper 55 is loaded in the launcher 52, and the water in the water supply tank 57 is sent into the launcher 52 as a high-pressure water stream by a pump 56. As a result, the decoking process is started.

The sweeper 55 loaded in the launcher 52 is
It is introduced into the pipeline 1'' by a high-pressure water flow applied by a pump 56. The base portion 55 of the sweeper 55
Although the outer diameter of pipe a (see FIG. 2) is normally larger than the inner diameter of pipe 2, it can be introduced into pipeline 1 because it is elastically deformed by the high pressure water flow applied via launcher 52. A cutting blade 5 is provided on the outer periphery of the sweeper 55.
Since the cutting blade 5b is buried, the cutting blade 55b firmly attaches to the inner wall of the pipe 2 and scrapes off the stacked scale 25 during the traveling process of the hex sweeper 55. Note that the scraped pieces of scale 25 are swept away by the water flow leaking from the gap slightly formed between the sweeper 55 and the inner wall of the pipe 2. The water is then drained into a drainage tank 58 via the receiving trap 50.

The sweeper 55 that has traveled through the pipeline 1' reaches the receiving trap 50, which is configured similarly to the launcher 52. Generally, when performing decoking processing using the sweeper 55, the sweeper 55 It is necessary to make the round trip several times within the pipeline 1, for example, about 50 to 60 times. For this reason, as shown by the broken line, through the pump 59 to the receiving truck 50 side,
A flow path for supplying a high-pressure water flow from a water supply tank 57 is formed, and the receiving trap 50 is used as a launcher. This allows the decoking process to be performed by continuously moving the sweeper 55 back and forth over the entire length of the pipeline. In addition, pipeline 1
If decoking is required partially, H-type return bend 3 at the corresponding location is required.
What is necessary is to attach the short pipe 30 to the pipe and connect the launcher 52 and the receiving 1-wrap 50. Of course, it is also possible to perform the decoking process on a single pipe.

In the embodiment described above, the short tube 30 is fixed to the cylindrical portion 5.6 of the body 8 via the centering ring 36 using the opening 20.21 used when attaching the plug 9. In carrying out the present invention, this fixing method does not necessarily have to be used. Note that when the cylindrical portion 5.6 is formed with a passage having the same inner diameter as the short pipe 30, the tips 30a and 30b of the short pipe 30 and the pipe 2a',
It is not necessary that the end portions of 2b and 2b are in close contact with each other. Also,
A flow path 7 formed in the body 8 of the H-type return bend 3
Even if the cross section of a is circular, the plugs 9, 10
The receiver is face 11. The shape of j2 is often not suitable for running the sweeper 55, and the present invention is equally applicable to this case as well.

〔Effect of the invention〕

As explained above, in the present invention, pipes connected by a return bend such as those used in a heating furnace are connected by bypassing a flow path having a non-circular cross section formed in the return bend. , so that they are connected via a connecting pipe with a circular cross section. Therefore, when cleaning the inside of the pipe using the sweeper, it becomes possible to clean the pipes continuously without removing each individual pipe from the return bend, and the cleaning process becomes much more efficient.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of essential parts showing an embodiment of the present invention. FIG. 2 is a sectional view of essential parts showing one embodiment of the present invention. FIG. 3 is a schematic diagram of a pipeline to which the present invention is applied. FIG. 4 is a schematic diagram showing a pipeline in operation before the present invention is applied. FIG. 5 is a perspective view of essential parts showing an example of an I type return bend. 1. ...Pipeline (in operation) 1' ...Pipeline (for cleaning) 2...Pipe 3...) (Mold return bend 5.6...Cylindrical part 7...Connection part 8...Body 30...Short pipe 36...Set ring 45...Elbow-50...Receiving trap

Claims (3)

[Claims] (1) Both pipes with a circular cross section are connected to the body of the return bend, and the fluid sent from one pipe is directed to a channel deflection plug attached to the body and a plug formed in the body. In a method for cleaning the inside of a pipeline, the plug is removed from a body, a connecting pipe having a circular cross section is attached to the body, and the connecting pipes are connected to each other. By making fluid-tight communication with the pipes, a flow path bypassing the flow path formed in the body is formed, and a sweeper for removing foreign matter adhering to the inner wall of the pipe is passed through one pipe. 1. A method for cleaning an inside of a pipe, characterized in that the pipe is then continuously passed through the connecting pipe into the other pipe. (2) The connecting pipes include two straight pipes that are attached to face each pipe connected to the body, and a U-shaped pipe that communicates between the two straight pipes. A pipe cleaning method according to claim 1, characterized in that the method comprises: (3) The sweeper is composed of a base made of a cylindrical elastic body with an outer diameter larger than the inner diameter of the pipe, and a cutting blade fixed to the outer periphery of the base, and a fluid is applied from behind the base. The inside of the pipe according to claim 2, characterized in that the base body travels inside the pipe while being elastically deformed by pressure, and the foreign matter stacked inside the pipe is scraped off by the cutting blade. Cleaning method.