JP3452248B2 - Pigs for cleaning or painting inside pipes and their use - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pig used for cleaning and painting the inner surface of a pipe and a method of using the pig.

[0002]

2. Description of the Related Art In buildings, condominiums, various plants, etc., a large amount of piping is used to carry various fluids.
If these pipes are used for a long period of time, rust or corrosion will occur on the inner surface thereof, or the deposits will narrow the flow path, and the function as pipes will decline, and eventually they will not be usable. As a means for preventing the deterioration of the function or for recovering the deteriorated function, cleaning or painting using a pig is performed. Usually, a cleaning or painting pig generally has a shape in which a cone or a truncated cone is combined with a tip of a cylinder, and is made of a material according to its use. After the pig is inserted into the pipe to be cleaned or painted, the pig is cleaned or moved by moving it in the pipe by a pressure-feeding extrusion method that sends compressed air or the like to the downstream side or a suction method that depressurizes the upstream side. Perform painting work.

First, a cleaning pig is used to clean the target pipe. The cleaning pig is a side surface having a shape, a configuration, or a material, or, according to the type, physical properties, or quantity of rust, a corrosion product, or a deposit to be cleaned.
The shape and material of the attachment, which is additionally attached to the side surface of the pig when the degree of deposition or adhesion is severe, is selected. As the pig moves in the pipe, its side surface is rubbed against the pipe inner surface or the inner surface of a deposit or the like to perform grinding or polishing. The peeled material such as rust that has been ground or polished is discharged from the target pipe along with the air flow that conveys the pig. In order to rub the side surface of the pig effectively, it is common to select a pig that has a cylindrical part with an outer diameter that is almost equal to the inner diameter of the pipe.However, due to corrosion products and deposits, the effective inner diameter of the pipe is If it is much smaller than the inner diameter of the pipe,
To prevent the pig from getting stuck in the middle of the pipe,
First insert a pig having an outer diameter that matches the effective inner diameter, then change to a slightly larger outer diameter, and finally a pig that has an outer diameter that is approximately equal to the original pipe inner diameter. The operation to pass through may be performed.

After the cleaning is completed, the coating is carried out using the coating pig. In the case of painting, a required amount of paint is inserted in front of the traveling direction of the painting pig. The pig for painting pushes the paint while advancing and pushes the paint against the inner surface of the pipe to perform the painting work. In order to save the energy required to move the pig and to prevent the pig from being biased to one side in the pipe in order to coat the entire inner surface of the pipe uniformly, A pig with a column is selected.

In any case, the conventional method employs a pig having a cylindrical portion having an outer diameter substantially equal to the effective inner diameter of the pipe (the same as the original inner diameter of the pipe when the inside of the pipe is fairly clean). By closing the inside of the pipe almost exactly with a pig, the side surface of the pig is rubbed against the inside of the pipe or the inside of deposits, etc., or pressed to perform the role of cleaning or painting. The piping has been divided into two chambers, one on the downstream side and the other on the upstream side, and the chamber on the downstream side has been pressurized, or the chamber on the upstream side has been decompressed in order to move the pig.

[0006]

A pipe cleaning or painting pig that uses the rotary motion of a pig that has been experimentally grasped and is supported by the eccentric double annulus inner flow theory, and a pig using the same The purpose is to provide a method for cleaning or painting the inner surface of the pipe.

[0007]

The present invention has a cylindrical portion having an outer diameter of 50 to 90% of the effective inner diameter of a pipe to be cleaned or painted, so that the cleaning work is performed in a rotary motion when being conveyed by an air flow. Pig for painting or painting.

Further, the present invention has a cylindrical portion made of an impregnating porous material and having an outer diameter of 50 to 90% of the effective inner diameter of the pipe for cleaning or painting. It is a painting pig that rotates.

Further, the present invention is a method for cleaning or painting the inner surface of the pipe by the rotational movement of the pig, which is generated by moving the above-mentioned cleaning or painting pig in the target pipe by the pressure feed extrusion method or suction method. .

As shown in FIG. 4, the behavior of the pig is observed in an experimental apparatus in which the transparent pipe 61 is the portion corresponding to the pipe to be cleaned or painted. The pig 5 used in the experiment is
Colors are applied in vertical stripes on the side surface of the cylinder so that the state of the rotating motion can be clearly understood. As in the past, if you use a pig that has a cylinder with an outer diameter that is almost equal to the effective inner diameter of the pipe,
Either by pressurization from the downstream side or suction on the upstream side, the pig / paint insertion section 66 at the initial piping inlet is used.
While being inserted into the pipe, it moves in the pipe without making noticeable rotation, reaches the pig / paint receiving device 62 at the end of the target pipe, and is collected.

On the other hand, when several kinds of test pigs 5 having the outer diameter of the cylindrical portion are gradually reduced and they are sequentially inserted into the test device and tested, the outer diameter is slightly smaller than the effective inner diameter of the pipe. The pig having a cylindrical portion with a diameter starts rotating while moving in the target pipe, and revolves along the inner surface of the pipe while rotating. The rotation axis and the revolution axis are substantially coincident with the axial direction of the target pipe. The intensity of its rotation and revolution is
It becomes maximum when the outer diameter of the pig is made smaller than the effective inner diameter of the pipe to some extent, and when it is further made smaller, the rotation becomes gentle. Furthermore, if the pig is changed to a cylinder having an outer diameter extremely smaller than the effective inner diameter of the pipe, the pig moves to an unstable position as if it was hit by a gust of wind, and is blown to the end of the target pipe. In this case, the directions of the rotation axis and the revolution axis are also not constant.

The rotational movement of the pig can be explained by the theory of fluid flowing in the eccentric double annular ring, that is, the so-called eccentric double annular internal flow theory. That is, as shown in FIG. 6, when a pig having an outer radius a of a cylindrical portion is flying in a pipe having an inner radius R which is slightly larger than a, the pig is not surrounded by the outer periphery of the cylindrical portion of the pig. There is an annular gap that is divided by heavy circles. Considering only the vicinity where the pig is present, the airflow is flowing through the annular flow path. Since the position of the central axis of the pig does not always coincide with the central axis of the pipe as shown in FIG. 6, the airflow actually flows in the eccentric double annulus with the pig on it. The relationship between the fluid flowing in the eccentric double annulus and the rotational movement of the pig can be explained as follows.

Here, the axial velocity of the pig is U, the length of the cylindrical portion of the pig is D, the moment of inertia of the pig is I, the rotation angle of the pig is θ, its angular velocity is ω, the flow rate of the fluid is Q, The density of the fluid is ρ, the viscosity of the fluid is μ, the shear stress generated in the direction of damping the rotation of the pig due to the viscosity of the fluid is τ _ωθ1 , and the shear acting in the direction of accelerating the rotation of the pig caused by the force that propels the pig. _{Let the} stress be τ _{ω θ2} .

The gap between the pig and the inner wall of the pipe is (Ra) on average, and when the gap is small, the velocity of the fluid starts from 0 (zero) in the portion in contact with the inner wall of the pipe and changes to the cylinder of the pig. It is approximately conceivable that the portion U, which is in contact with the side wall, changes linearly. Therefore, the flow rate Q of the fluid
Is the sum of the flow rate in the central part moving with the pig and the flow rate in the gap where the velocity decreases gradually;

[Equation 1] Can be expressed as Solving this equation for U;

[Equation 2] Becomes

On the other hand, the equation of motion relating to the rotation of the pig;

[Equation 3] In, M is a moment acting in the rotation direction of the pig, and two moments acting on the side wall of the pig, that is,
It is the sum of the shear moment that damps the rotation of the pig due to viscosity and the shear moment that accelerates the rotation generated by the force of the fluid propelling the pig, and is expressed as follows.

[Equation 4]

Here, the rotation of the pig is reduced due to the viscosity of the fluid.
Shear stress τ in the direction of decay _ωθ1Is a pig circle
In proportion to the rotation speed aω of the outer circumference of the pillar, the pig and the pipe inner wall
Is inversely proportional to the gap (Ra) of
Because;

[Equation 5] On the other hand, the shear stress τ _{ω θ2 which} is generated by the force of the fluid propelling the pig and acts in the direction to accelerate the rotation of the pig is obtained by dividing the force ρQU of propelling the fluid by the pig by the outer peripheral area 2πaD of the cylindrical portion of the pig. Since it is approximately considered to be proportional to, if the proportional constant is k;

[Equation 6] Becomes Substituting these into Equation 4;

[Equation 7] Becomes

When the pig rotates stably on the flow of fluid, that is, when the pig rotates at a constant speed, its angular acceleration d ² θ / dt ² is 0 (zero). Therefore, the left side of Expression 3 is 0 (zero), and therefore the moment M acting in the rotation direction of the pig on the right side is also 0 (zero).
Is. The left side of Equation 7 representing M is set to 0 (zero),
Further substituting Equation 2 and rearranging;

[Equation 8] Becomes

Considering that the outer radius a of the cylindrical portion of the pig is variable in the range of R ≧ a ≧ 0, (R−a) / a ² (R ² + a ² ) in this equation will be considered. ,
It becomes 0 (zero) when a = R, and increases unilaterally as a decreases. Therefore, when the inner radius R of the target pipe and the outer radius a of the pig are equal, the rotational movement of the pig does not occur, and unless the flow rate Q of the fluid or the length D of the cylindrical portion of the pig is significantly changed, the outer radius of the pig is changed. It can be seen that when the value is reduced, the angular velocity at which the pig rotates stably increases, that is, it rotates more often.

However, the above examination is made on the assumption that the gap (R-a) between the pig and the inner wall of the pipe is small, so that it cannot be established if a becomes too small. According to the experiment, when the ratio of the outer radius of the pig to the inner radius of the pipe is gradually decreased, the rotation of the pig gradually becomes faster and more vigorous, but at some point the momentum becomes maximum, and the radius ratio further increases. It was observed that the speed of rotation slowed down when was decreased.

FIG. 5 shows the ratio of the outer radius of the pig to the inner radius of the pipe obtained in the experiment using the apparatus of FIG. 4, that is, the radius ratio (%) and the relationship between the rotational force of the pig obtained by the inspection. Indicates. As shown in the figure, the momentum of rotation of the pig increases from 0 (zero) when the radius ratio is 100%, increases with the decrease of the radius ratio, reaches a maximum value at about 83%, and further reduces the radius ratio. And decrease. The speed of rotation of the pig is high because the radius ratio is 50 to 9
It is 0%, preferably 70 to 85%.

Furthermore, the pig revolves at the same time as it rotates. The axis of rotation and the axis of revolution are substantially coincident with the axial direction of the target pipe. As the momentum of rotation increases, the momentum of revolution also increases, and when the momentum of rotation weakens, the momentum of revolution also weakens. The rotating and revolving pig advances while pressing the inner surface of the target pipe hard or rubbing the inner surface. This pushing force or rubbing force generated by the rotational movement of the pig has a conventionally selected pig, that is, a cylindrical portion with an outer diameter almost equal to the inner diameter of the pipe. The force that moves inside and pushes the inner surface of the pipe mainly depends on the elastic force of the pig itself and the force generated by the structure that slightly deforms a part of the pig to the outside due to the pressure from the wake. Much larger than ,.

Considering the pipe to be actually cleaned or painted, particularly in the case of cleaning, there are cases where the effective inner diameter of the pipe is significantly smaller than the original inner diameter of the pipe due to corrosion products and deposits. Conceivable. Therefore, it is possible to maximize the force pushing or rubbing the inner surface of the target pipe because the eccentric double annulus internal flow theory can be used to expect a strong rotational movement, The pig is selected in the range of 50 to 90%, preferably 70 to 85% in terms of the radius ratio to the actual effective inner diameter in consideration of not only the inner diameter but also its corrosion products and deposits. . By moving the pig whose outer diameter of the cylindrical portion is selected according to the present invention in the target pipe by the pressure-feeding extrusion method or the suction method, a strong rotary motion is generated in the pig, and the rotary motion causes the pig to move to the inner surface of the pipe. Force to press, or
It produces the effect of maximizing the rubbing force.

The pig cleans the inner surface of the target pipe, that is,
Grinding and grinding is exactly due to the force of the pig pushing and rubbing the inner surface of this pipe, and the fact that these forces are greater than in conventional methods means that cleaning is both powerful and efficient. The effect that it can be done is produced. In addition, in order for the pig to coat the inner surface of the target pipe uniformly and densely, it is necessary for the pig to press the paint strongly against the inner surface of the pipe and rub it against the inner surface of the pipe. The fact that the force applied is larger than that of the conventional method has the effect that a more uniform and dense coating film can be formed on the inner surface of the target pipe.

In the coating operation, there is a case where it is desired to form a coating film having an extremely thin thickness, for example, a thickness of several microns, as in the case of coating titanium oxide or the like. In that case, the coating pig is made of a porous material with impregnation,
Liquid titanium oxide, which is paint, is not inserted in front of the direction of movement of the coating pig in advance, but it is impregnated into the porous coating pig itself and then is advanced in the target pipe by the pressure-feed extrusion method or suction method. Let Porous coating pigs that are impregnated with paint are pressed against the inner surface of the pipe by pushing the coating pig itself all the way while traveling while rotating and revolving in the air flow. An extremely thin and dense coating film can be produced by leaving the coating film evenly on the inner surface of the pipe.

That is, by moving a coating pig having an outer diameter of a cylindrical portion selected according to the present invention and made of an impregnating porous material in the target pipe by a pressure feed extrusion method or a suction method. The strong rotational movement is generated in the pig, and the rotational movement brings about an effect that an extremely thin and dense coating film of several microns can be formed.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION An example of an embodiment of the present invention will be described with reference to the drawings. Needless to say, the present invention is not limited to such an embodiment, and various modifications may be made to its specific structure within the scope of the present invention.

FIG. 1 shows an embodiment of the cleaning pig of the present invention. The cleaning pig 1 includes a cylindrical portion 11 and a truncated cone portion 12.
The inner diameter of the cylindrical portion is an effective inner diameter of the cleaning / painting target pipe 2, that is, the cleaning / painting target pipe 2 so that a strong rotational motion is generated by the eccentric double annular flow.
50 to 90% of the actual inner diameter 22 reduced by the deposit 21 deposited on the inner surface of the, preferably 70 to 85
% Has been selected. The shape and configuration of the side surface of the pig is selected according to the type, physical properties, or amount of the deposit or deposit, but in this embodiment, five rows of polishing surfaces 13 formed in a band shape are provided.

The cleaning pig 1 advances in the direction of arrow 14 by a pressure-feed extrusion method or a suction method. While advancing, the eccentric double annular flow causes the rotation indicated by the arrow 15 and the revolution indicated by the arrow 16. These strong rotational movements press the polishing surface 13 of the cleaning pig 1 against the inner surface of the target pipe with a strong force, or rub against the inner surface of the target pipe with a strong force. Due to this movement, the adhered / deposited material 21 is strongly and effectively stripped from the inner surface of the target pipe, and the separated material 23 is discharged from the target pipe by riding on the air flow.

FIG. 2 shows an embodiment of the coating pig of the present invention. The painting pig 3 has a shape in which a column portion 31 and a truncated cone portion 32 are combined in the same manner as the cleaning pig, and the diameter of the column portion is 50 to 9 which is the effective inner diameter of the cleaning / painting target pipe 2.
0%, preferably 70 to 85% is selected. The coating pig 3 also advances in the direction indicated by the arrow 33 by the pressure feed extrusion method or the suction method. While traveling, the eccentric double annular flow causes rotation indicated by arrow 34 and arrow 35.
Make the revolution indicated by.

In the painting operation, before the movement of the pig is started, a required amount of paint 25 is inserted in front of the traveling direction of the painting pig. When the air flow in the target pipe is established by the pressure-feeding extrusion method or the suction method, the paint 25 is pushed and advances, and a part of the paint 25 adheres to the inner wall 27 of the pipe in advance as droplets 26. The coating pig 3 advances while rotating on its own axis 34 and revolving 35 while propelling the paint 25 and pushing the paint against the inner surface of the pipe with a strong force to form a uniform coating film 28. In particular, this method is suitable for undercoating where it is desired to form a coating film having a certain thickness.

The above is an example of the coating work for forming a coating film having a certain thickness. However, as in the case of coating titanium oxide or the like, a coating film having an extremely thin thickness, for example, a few microns is prepared. If desired, paint pigs should be made of a porous material with impregnation. Liquid titanium oxide, which is a paint, is not inserted in the forward direction of the coating pig as in the case above, but it is impregnated in the porous coating pig itself in advance and the same as above. Then, the inside of the target pipe is advanced by the pressure feed extrusion method or the suction method. The porous coating pig that is impregnated with the paint, while advancing while rotating and revolving along with the air flow, presses itself against the inner surface of the pipe evenly, so that the impregnated paint is gradually and evenly distributed. Moreover, an extremely thin and dense coating film can be formed by leaving it on the inner surface of the pipe.

FIG. 3 is an overall explanatory view of an embodiment of the cleaning method of the present invention or the coating method of the present invention.
The case where the suction method detailed in No. 1-152138 is adopted is shown. The target pipe 4 for cleaning or painting is not necessarily a single pipe, and as shown in FIG. 3, the main pipe 41 to a plurality of branch pipes 42,
Often divided into 43 and 44. A pig / paint receiving device 51 is provided at the open end of the main pipe 41, and a dust collecting device 52 and a suction device 53 are connected to the tip thereof by a pipe or a duct. It is desirable to provide a pressure adjusting valve 54 to keep the pressure on the suction side constant. on the other hand,
The open ends of the branch pipes 42, 43 and 44 are
A suction valve 56 for taking in suctioned air is provided at the tip of the paint insertion portion 55. Pig / paint insertion part 55
Is so constructed as to be easily removable by a socket joint or the like so that a pig or paint can be easily inserted therein.

In order to perform the cleaning operation, one of the branch pipes, for example, the branch pipe 43 is selected, and the cleaning pig is inserted into the pig / paint insertion portion 55. With the suction valves 56 of all the branch pipes closed, the suction device 53 is activated to make the inside of the target pipe 4 a negative pressure. After the negative pressure rises, only the intake valve 56 of the branch pipe 43 is slightly opened to introduce the outside air while adjusting the intake amount. The amount of intake is adjusted so that the instruction of the pressure gauge 57 is adjusted to the most appropriate value for the cleaning work obtained by conducting another experiment.

The taken-in air flows in the target pipe 4 toward the suction device 53, and gives the cleaning pig a strong rotational movement due to the eccentric double annular internal flow. The cleaning pig presses the side surface against the inner surface of the target pipe 4 with a strong force, or
By rubbing with a strong force, the cleaning operation proceeds strongly and effectively, and reaches the pig / paint receiving device 51 and stops. The peeled adhesion / deposit is collected by the pig / paint receiving device 51 and the dust collecting device 52. By repeating the same operation for each branch pipe, the cleaning of the entire target pipe 4 is completed. This operation may be repeated when the internal adhesion or accumulation is severe, and at that time, the outer diameter of the cylindrical portion of the cleaning pig may be changed according to the change in the effective inner diameter of the target pipe.

In order to perform the painting work, similarly, any branch pipe,
For example, the branch pipe 43 is selected, the paint is inserted into the pig / paint insertion portion 55, and then the painting pig is inserted on the flow side. After the negative pressure is set in the target pipe 4 and the negative pressure rises, only the suction valve 56 of the branch pipe 43 is slightly opened, and the outside air is introduced while adjusting the intake amount, as in the case of the cleaning work. Is. The amount of intake is adjusted so that the instruction of the pressure gauge 57 is adjusted to the most appropriate value for the coating work obtained by conducting another experiment. The air taken in from the suction valve 56 gives a strong rotational motion to the coating pig, and the coating pig pushes the paint with a strong force and presses the paint against the inner surface of the target pipe 4 to form a uniform coating film. While proceeding, it reaches the pig / paint receiving device 51 and stops. The surplus paint is collected by the pig / paint receiving device 51, and the paint that has been splashed and is on the air stream is collected by the dust collector 52. The same operation is repeated depending on the number of coating films to be formed,
Also, by repeating the same operation for each branch pipe, the coating of the entire target pipe 4 is completed.

When using a coating pig made of a porous material having an impregnating property, instead of inserting the paint into the pig / paint insertion portion 55, the coating pig is impregnated with the paint in advance. The impregnated coating pig may be inserted into the pig / paint insertion portion 55, and the suction construction method may be performed in the same manner as described above.

When coating a long pipe of several hundred meters in length, it is sufficient to coat the entire inner surface of the pipe with only the paint that has been impregnated in the coating pig in advance. It is possible that there will be a shortage. In that case, before passing through the impregnating porous coating pig, separately, by the usual method, that is, the pig / paint insertion portion 5
Paint is sent to the inside of the pipe by the method of inserting the paint into 5 and then inserting the pig on the flow side and then advancing the pig. After that, the porous coating with impregnation is applied. It is also conceivable to make the paint distributed by the previously passed pigs even through the operating pigs to make them even and make a fine coating film.

FIG. 4 shows an experimental apparatus for grasping the operating conditions in which the rotational movement of the pig is strong in the present invention and is most suitable for cleaning work or painting work. The portion 61 simulating the pipe to be cleaned or painted is made of a transparent material so that the behavior of the pig can be easily observed. A pig / paint receiving device 62 is provided at one end of the target pipe-corresponding portion 61, and a dust collecting device 63 and a suction device 64 are provided ahead of it.
Are connected by pipes or ducts. It is desirable to provide a pressure adjusting valve 65 for keeping the pressure on the suction side constant. A pig / paint insertion portion 66 is provided at the other end of the target pipe-corresponding portion 61, and a suction valve 67 and a pressure gauge 68 for taking in the air to be sucked are provided at the tip thereof, as in the actual machine. .

Pigs used in the experiment are colored in vertical stripes on the side surfaces of the cylindrical portion so that the state of the rotational movement can be clearly understood. Depending on the inner diameter of the pipe, the radius of the pig, and
By changing the opening degree of the suction valve 67, the momentum of the rotational movement of the pig is strong, and the optimum operating condition for the cleaning work or the painting work is selected.

FIG. 5 shows an example of the results obtained by the experimental apparatus shown in FIG. The vertical axis represents the momentum of rotation of the pig observed in the transparent target pipe equivalent portion 61, and the horizontal axis represents the ratio of the outer radius of the pig to the inner radius of the pipe, that is, the radius ratio, and the experimental results are shown. . In the case of a pig having a radius ratio of 100%, that is, an outer diameter commensurate with the conventionally used pipe inner diameter, no rotational movement of the pig occurs and the rotational force R ₁₀₀ is 0 (zero). When the radius ratio is changed to 83%, 65%, and 50% and the test is performed, the corresponding rotational momentum R ₈₃ , R ₆₅ , R
₅₀ is as shown in the figure, R _{8 3} is the strongest,
It decreases gradually at R ₆₅ and R ₅₀ . From this result, a pig having a cylindrical portion with an outer diameter of 50 to 90%, preferably 70 to 85% of the effective inner diameter of the pipe to be cleaned or painted,
It is judged to be the most effective.

[0041]

The cleaning or painting pig of the present invention allows
The force by which the pig pushes the inner surface of the pipe by the rotary motion, or the rubbing force is extracted to the maximum, and the cleaning or painting method of the present invention that utilizes that force makes the cleaning powerful and efficient, and This produces an effect that a uniform and dense coating film can be formed on the inner surface of the target pipe. Further, the impregnating porous coating pig of the present invention brings about an effect of forming an extremely thin and dense coating film of several microns.

[Brief description of drawings]

FIG. 1 shows an embodiment of a cleaning pig of the present invention,
(A) is a side view, (b) shows the AA arrow view.

FIG. 2 is a side view showing an embodiment of the coating pig of the present invention.

FIG. 3 is an overall explanatory view of an embodiment of a cleaning method of the present invention or a coating method of the present invention, showing a case where a suction method is adopted.

FIG. 4 is an explanatory view showing an experimental device for grasping the optimum operating condition in the present invention.

5 is a diagram showing an example of a result obtained by the experimental apparatus of FIG.

6A and 6B are explanatory views of the rotational movement of the pig based on the eccentric double annular internal flow theory, in which FIG. 6A is a side view and FIG.

[Explanation of symbols]

1 Cleaning Pig 2 Cleaning and painting target piping 3 Painting Pig 4 Pipes for cleaning or painting 5 test pigs 11 Column 12 Frustum 13 Polished surface 14 Pig traveling direction 15 pig rotation Revolution of 16 pigs 21 Adhesion / Deposit 22 Effective inner diameter of piping 23 Detached deposits / deposits 25 paint 26 Splashes of paint 27 Paint on the inner wall 28 Coating film 31 Column 32 truncated cone 33 Pig traveling direction 34 Pig rotation Revolution of 35 pigs 41 Main pipe 42,43,44 branch pipe 51 Pig / Paint Receiving Device 52 Dust collector 53 Suction device 54 Pressure regulating valve 55 Pig / Paint Insert 56 Suction valve 57 Pressure gauge 61 Transparent piping that simulates piping to be cleaned and painted 62 Pig / Paint Receiving Device 63 Dust collector 64 suction device 65 Pressure control valve 66 Pig / Paint Insert 67 Inhalation valve 68 Pressure gauge

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI E03C 1/302 B08B 9/04 Z E03F 9/00 9/06 F16L 55/26 F16L 55/00 Q (58) Fields investigated (58) Int.Cl. ⁷ , DB name) B08B 9/04 B05C 7/06 B05D 7/22 B08B 9/027 B08B 9/053 E03C 1/302 E03F 9/00 F16L 55/26

Claims (3)

(57) [Claims] 1. The effective inner diameter of the pipe to be cleaned or painted is 5
A cleaning or painting pig that has a cylindrical portion with an outer diameter of 0 to 90% and that makes a rotational movement when transported by an air flow. 2. The coating pig according to claim 1, which is made of an impregnating porous material. 3. A method for cleaning or painting the inner surface of a pipe by the rotational movement of the pig, which is generated by moving the pig of claim 1 or 2 in the target pipe by a pressure-feeding extrusion method or a suction method.