JP3487668B2 - How to reduce and remove branch pipes - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal branch pipe fixed to the pipe support plate by inserting it into a hole provided in the pipe support plate and expanding the insertion portion located in the hole. The present invention relates to a method for reducing the diameter of a desired portion of a pipe expanding portion for removing it from the pipe support plate, and a method for removing a branch pipe using the method. Typical examples of the branch pipe to which the present invention is applied include branch pipes mounted in large numbers on heat exchangers, smoke pipe boilers, water pipe boilers, and the like. Hereinafter, the removal work of the branch pipe for the maintenance of the heat exchanger will be described as an example.

[0002]

2. Description of the Related Art Generally, a branch pipe provided in a heat exchanger has its end portion inserted and fixed to a pipe support plate (tube plate), and in many cases, a pair of pipe support plates is provided. It is arranged at a distance, and both ends of the branch pipe are fixed to the pipe support plate. To fix this branch pipe to the pipe support plate, in many cases,
As shown in FIG. 11, the branch pipe 3 is inserted into the hole 2 provided in the pipe support plate 1.
Through the end portion, and the end portion including the insertion portion 3a located in the hole 2 is subjected to pipe expansion processing to form the pipe expansion processing portion 3b, and the insertion portion 3a
Is pressed against and fixed to the inner surface of the hole 2. At this time, the expanded diameter portions 3c, 3 having a diameter larger than the inner diameter of the hole 2 in the portion of the expanded pipe processing portion 3b located outside the pipe support plate 1 due to the expansion processing.
Often d is formed. Further, as shown in FIG. 12, one or a plurality of circumferential locking grooves 4 are provided on the inner surface of the hole 2, and the expanded diameter portion 3e is provided at a portion corresponding to the locking groove 4 of the pipe expanding portion 3b. In some cases, resulting in stronger engagement. Further, there is also one in which the tip of the branch pipe 3 projecting from the pipe support plate 1 is subjected to flare processing to form a flare processing portion 3f to further secure the fixing.

When the branch pipe 3 is corroded or damaged, it is necessary to remove the branch pipe 3 from the pipe support plate 1 and replace it. A conventional method for extracting the branch pipe 3 is to heat the expansion-inserted insertion portion 3a with a gas torch to make the insertion portion 3a to be thermally expanded into the hole 2.
By compressing and yielding by the restraint by the inner surface of the, the insertion portion 3a is relaxed from the hole 2 by applying a heating diameter reduction operation that the insertion portion 3a is reduced in diameter after cooling.
The branch pipe 3 was pulled out in the direction of arrow A or in the direction of arrow B. In addition, the flared portion 3 is provided at the end of the branch pipe 3.
When forming the f, when the branch pipe 3 is pulled out in the direction of the arrow B, the flared portion 3f is scraped off with a grinder or the like in advance, or the flared portion 3f is circumferentially cut with a gas torch. In order not to damage the tube support plate 1, the three locations apart from each other can be extracted by fusing in the tube axis direction, then squeezing with a hammer or the like, or by grinding the flared portion to make it thinner.

[0004]

However, in the conventional heating and diameter-reducing operation, the diameter reduction ratio generated in the insertion portion 3a is 1%.
The degree of relaxation was low, and a large force was required for extraction, and extraction was extremely difficult. Moreover,
When the expanded diameter portions 3c and 3d are formed in the front and rear of the insertion portion 3a of the branch pipe 3 and the expanded diameter portion 3e is formed in a portion facing the locking groove 4, the expanded diameter portions 3c, 3d and 3e are formed. On the other hand, even if the above-mentioned heat reduction operation is applied, the diameter reduction hardly occurs, and the enlarged diameter portions 3c, 3d, 3e are often caught by the tube support plate 1 and cannot be removed as they are.
Therefore, in such a case, if it is possible to access the expanded diameter portions 3c, 3d, it is scraped off with a grinder to make it easier to extract the branch pipe. We have devised a removal method for each object, such as melting it in the axial direction and then squeezing it with a hammer etc., but in each case, there is a significant increase in man-hours and the diameter expansion The pipe support plate is often damaged when the portion is scraped off or when the pipe expanding portion 3b is melted, and in that case, there is a problem that a large amount of cost is required for the repair. Further, when the flared portion is scraped off or melted, the pipe supporting plate is often damaged, and even in that case, there is a problem that a large amount of cost is required for the repair.

Therefore, if there is a sufficient gap between the pipe expanding portion 3b for fixing the branch pipe to the pipe supporting plate, particularly the expanded diameter portions 3c, 3d, 3e, etc., with respect to the hole of the pipe supporting plate. If the diameter can be reduced to a high degree so as to be ensured, the removal of the branch pipe from the pipe support plate becomes extremely easy.

The present invention has been made in view of the above circumstances , and is arranged at a distance such as a tube plate of a heat exchanger.
Branch pipe with both ends inserted and expanded and fixed to a pair of pipe support plates
It is an object of the present invention to provide a method for reducing the diameter of a branch pipe capable of highly reducing the diameter of the expanded pipe processing portion . Another object of the present invention is to provide a method for removing a branch pipe, which can efficiently, economically, and safely remove the branch pipe from the pipe support plate by utilizing the diameter reducing method. .

[0007]

A method for reducing the diameter of a branch pipe according to the present invention is characterized in that a part of a metal pipe body is red-heated to reduce the deformation resistance, and the red-heated section is pulled in the pipe axial direction to cause tensile yielding. If
It utilizes the phenomenon that the diameter decreases simultaneously with the stretching during the tensile yielding.

By the way, the branch pipe to which the present invention is applied is expanded by being inserted into a hole provided in a pipe support plate having a thickness of several tens of mm or more or 100 mm or more, and therefore, FIG.
As shown in FIG. 12, the insertion portion 3a is tightly attached to the inner surface of the hole 2 so that a large frictional force exists between the two and the expanded diameter portion 3
The locking action of c, 3d, and 3e also acts. In order to cause a diameter reduction phenomenon due to tensile yielding on such an object, when the section including the insertion portion 3a and the enlarged diameter portions 3c, 3d, and 3e is red-heated and pulled from both sides, the tensile yielding occurs in the pipe axis direction. It was found that the red hot zone could not be reduced in diameter because it concentrated in a local area and was broken.

[0009] Therefore, as a result of intensive investigations by the inventors of the present invention to apply the diameter reduction phenomenon due to tensile yield to the pipe expansion processing portion of the branch pipe, as a result, if the red hot zone is made smaller, tensile yield occurs without breaking and shrinkage occurs. If the diameter can be increased and the diameter needs to be reduced over a long section, red heat and tensile yield for such a small section can be changed sequentially or continuously by changing the position. The inventors have found that the diameter of a desired section of a pipe expansion portion can be reduced favorably without causing breakage, and have achieved the present invention.

That is, according to the invention of claim 1, the distance is increased.
Both ends of C and D are inserted into a pair of pipe support plates arranged as
The expanded pipes at both ends of the expanded pipe are fixed
The narrow section in the pipe expansion processing section is heated by the inside of the branch pipe.
Ring-like red heat, and the tube axial direction
Shrinkage by applying a tensile force in the opposite direction to cause tensile yield and contraction
It is a method to reduce the diameter by applying the diameter method, and first, the C end
For the diameter reduction of the pipe expansion part on the side, pulling the pipe,
A ring-shaped red-hot operation with a tensile force acting on the pipe end
, The heating means inserted in the pipe, the C end of the C end side pipe expansion processing part
From the side toward the D end side
In order from the C end side to the D end side.
And then yield to the pipe, and then the pipe expansion part on the D end side.
By reducing the diameter of the operation from the D end side, the operation at the C end side
By turning over to the D end side and replacing it
Te, sequentially expanded pipe pressurized coated portion of the D-end side toward the C-terminal side from D-end side
By pulling and yielding to
A condensation radial direction method of the branch tube, characterized in that to reduced diameters.

According to a second aspect of the present invention, the elements are arranged at a distance.
Insert both ends of C and D into the pair of pipe support plates
The expanded pipes at both ends of the expanded branch pipe.
The narrow section in the section is made annular by heating from the inside of the branch pipe.
A tensile force in the axial direction of the pipe in the section that is red-heated and annularly red-hot
Is applied to cause tensile yielding and reduce the diameter.
A method for shrink-to use, first, the C-terminal side tube expansion pressure
Reduce the diameter of the work part and pull the pipe to pull it to the pipe end on the C end side.
Insert the ring-shaped incandescent operation into the pipe in the form of applying force.
Put the heating means into the C end side from the C end side to the D end side of the pipe expansion processing part.
By adding it in the form of moving it toward
The pipe processing part is pulled and yielded in order from the C end side to the D end side.
Then, reduce the diameter of the pipe expansion part on the D end side to the C end.
Side of the pipe end is applied with a tensile force, and the heating means D
Move from the C end side to the D end side of the end side pipe expansion processing part
By adding a shape, the pipe expansion part on the D end side can be added to the C end side.
To the D end side in order, and then yield to the C and D ends.
Diameter of branch pipe characterized by reducing the diameter of the expanded pipe
Is the way .

The invention according to claim 3 is arranged at a distance.
Insert both ends of C and D into the pair of pipe support plates
Both ends by applying the method according to claim 1 to the branched branch pipe.
The diameter of the pipe expansion part is reduced, then the branch pipe is removed from the pipe support plate.
By removing the branch pipe, which is characterized by pulling out and removing
There is . The invention according to claim 4 is a pair arranged at a distance.
Insert both ends of C and D into the tube support plate of, expand the tube, and
Claim 1 or 2 in the branch pipe fixed by flaring the end
Apply the described method to reduce the diameter of the pipe expansion
Remove at least one flared part or remove
After shaping so that it can pass through the hole in the tube support plate,
Characterized by pulling out the branch pipe from the pipe support plate and removing it
It is the removal how the branch pipe that. According to the invention of claim 5, the distance
Insert the both ends of C and D into a pair of pipe support plates
Branch that has been inserted, expanded, and flared at the tube end and fixed
Expansion of both ends by applying the method according to claim 1 or 2 to the tube
Reduce the diameter of the processed part, then cut the middle part of the branch pipe
In particular, the branch pipe is pulled out from the pipe support plate and removed.
This is the method of removing the branch pipe to be collected.

The present invention will be described in more detail below with reference to the drawings. FIG. 1 shows the principle of the diameter reduction method adopted in the present invention .
Of the branch pipe 3 fixed to the pipe support plate 1
The case where the diameter of almost the entire area is reduced will be described as an example. In FIG. 1 (a), first, a narrow width section 3g having a narrow width is red-heated annularly by heating from the inside of the branch pipe so that the problem of local yield fracture does not occur, and the red-heated section 3g is directed in the tube axial direction. The tensile force of is applied. This tensile force can be applied, for example, by pulling the tube end in the direction of arrow A. As a result, as shown in FIG. 1 (b), the red hot zone 3g is stretched by tensile yielding and its outer diameter is reduced. If the diameter reduction amount at this time is about 10%, it is possible without causing breakage. Thus, a high degree of diameter reduction can be performed on the narrow width section 3g without causing breakage.

When a predetermined amount of tensile yielding is caused in the section 3g, next, the narrow section 3h adjacent to the section 3g is made to annularly red heat by heating from the inside of the branch pipe, and the pulling force is applied to the red hot section 3h. To cause tensile yielding. At this time, since the temperature of the narrow section 3g that has been subjected to the tensile yielding is lowered and the rigidity thereof is increased, the tensile yielding does not progress and the fracture does not occur. If necessary, cooling air may be intermittently or continuously flowed in the branch pipe 3 to cool the tensile-yield region. Further, the red-heated section 3h may be positioned so as to partially overlap with the section 3g which was previously pulled and yielded. Hereinafter, the same operation is repeated, and finally, as shown in FIG. 1C, the narrow width section 3n including the expanded diameter portion 3d generated on the inner surface side of the tube support plate 1 is red-heated and tensilely yielded. According to Fig. 1
As shown in (d), it is possible to reduce the diameter of almost the entire pipe expansion portion 3b without causing breakage.

Here, the widths of the narrow width sections 3g, 3h, ... 3n, etc., which are red-heated and tensile-yield, are determined so that the problem of local yield fracture does not occur, and should be experimentally set according to the situation. However, as a guide, the wall thickness of the branch pipe is 2-1.
It is 0 times. In addition, the width of each narrow section when changing positions sequentially to heat red is usually constant, but even if it is changed as needed, for example, at a position where a high degree of diameter reduction is desired, the width of the narrow section is changed. It may be changed such that it is made smaller.

In the diameter reducing method , the order of performing the tensile yielding for the narrow width section is not limited to the case of proceeding from the tip side of the branch pipe 3 as shown in FIG. 1, but as shown in FIG. First, the narrowed section 3n on the rear end side of the pipe expanding portion 3b is tensilely yielded, then the position is successively changed toward the distal end side of the branch pipe 3 for tensile yielding, and finally the narrowed section 3g on the distal end side. May be yielded by pulling.

In order to apply a tensile force to the narrow sections 3g, 3h, ... 3n which are heated red, the tensile force is applied to one end or both ends of the pipe expanding portion 3b. At this time, when the tip end of the branch pipe 2 is gripped to apply a tensile force in the direction of the arrow A to the tip end of the branch pipe 2, when the amount of protrusion of the tip end of the branch pipe 2 from the pipe support plate 1 is large, If it is provided, it can be done by gripping the outer surface with a split clamp, and if that is not possible, fix the expanding anchor on the inner surface of the branch pipe or tap screw connection. Accordingly, the gripping tool can be brazed to the end face of the branch pipe. Further, the grip for applying a tensile force in the direction of the arrow B to the portion of the branch pipe 2 on the inner side of the pipe support plate 1 is performed by gripping the outer surface of the branch pipe at an appropriate position, or the side of the arrow B direction. This can be done by applying the above-mentioned gripping structure to the tube end of the.

By the way, as shown in FIG. 1, when the tensile yield is advanced from the end side of the branch pipe 2, for example, FIG.
As shown in (a) and (b), an unreduced diameter portion exists on the rear end side (right side) of the pipe expansion portion 3b than the narrow width sections 3g and 3h to be subjected to tensile yielding. The part blocks transmission of tensile force in the direction of arrow B. Therefore, even if a tensile force in the direction of the arrow B is applied to the end portion on the inner side of the pipe expanding portion 3b, it is not so effective. On the other hand, on the tip side (left side) of the narrow sections 3g, 3h, ... 3n to be subjected to tensile yielding, to which position is the tube support plate 1 constrained or already reduced in diameter? Even if the tensile yield is advanced, the tensile force in the direction of arrow A applied to the tip of the branch pipe effectively acts in the narrow width section in which the tensile yield is intended. Therefore, it is sufficient to apply a tensile force in the direction of arrow A to the tip of the branch pipe 3. Further, as shown in FIG. 2, when the tensile yielding is advanced from the rear end side of the pipe expanding portion 3b,
It is sufficient to apply a tensile force in the direction of arrow B to the rear end side of the pipe expanding portion 3b. In other words, when it is easy to apply a tensile force to the tip end side with respect to the pipe expanding portion 3b of the branch pipe 3, as shown in FIG. 1, the tensile yield is advanced from the tip end side, and vice versa. When it is easy to apply a tensile force to the pipe expansion processed portion 3b on the rear end side, it is preferable to advance the tensile yield from the rear end side as shown in FIG.

When a tensile force is applied only to one end side of the pipe expanding portion 3b of the branch pipe 3, the other end side may be fixed so as not to move in the pipe axis direction or may be freely movable. It may be. For example, in FIG. 1, when a tensile force in the direction of arrow A is applied to only the tip of the branch pipe 3 to perform a diameter reduction operation, the branch pipe portion on the right side of the pipe support plate 1 is piped by an appropriate means. It may be fixed so as not to move in the axial direction, or may be free to move. Even if this portion is free to move in the pipe axis direction, the insertion portion 3a of the pipe expansion processing portion 3b is tightly attached to the inner surface of the hole 2 and the diameter expansion portions 3d, 3
Since e and the like are locked to the tube support plate 1, the right-side regions of the red-heated narrow width sections 3g, 3h, etc. are constrained in the tube axial direction, and the red-heated section can be pulled and yielded. Is. In addition, as shown in FIG. 1C, the last narrow section 3
When n is red-heated for tensile yielding, when the expanded diameter portion 3d is reduced in diameter and is disengaged from the pipe support plate 1, the branch pipe 3 is indicated by an arrow A.
The tensile force in the direction moves in the direction of arrow A as a whole, and further tensile yield does not occur, but the purpose of diameter reduction is to reduce the branch pipe 3
Is to be pulled out from the hole 2 of the tube support plate 1, so that it can be pulled out as it is without any trouble.

The red heat temperature for tensile yielding in the above diameter reduction method is 700 to 1100 ° C., preferably 900 to 1 in order to make the deformation resistance of the red heat part necessary and sufficiently small.
It is better to set the temperature to about 100 ° C. It tensile force in the tube axis direction applied to the branch pipe 3 may be added to regulate the stress, may be added to regulate the pulling speed, in order not to lead to fracture or from the facility technical, stress The regulation method is more advantageous. However, even if the tensile force is low, if you continue to apply the tensile force, tensile yielding may progress and it may lead to fracture, so set the displacement amount according to the width of the narrow section that glows red, It is preferable to stop applying the tensile force at the time when the amount of displacement corresponding to the narrow section is reached. The amount of tensile yield generated in each narrow section may be constant, or a change such as increasing the amount of tensile yield may be given to a portion where the amount of diameter reduction is desired to be increased. A suitable range of the tensile force applied to the red-hot narrow section varies depending on the material and the red-hot temperature, but is generally in the range of 5 to 50 MPa.

The heating operation and the pulling operation for causing the tensile yielding in the narrow section may be performed simultaneously,
The heating operation may be performed after the heating operation, or the heating operation may be performed while the drawing operation is performed.

The heating for making the narrow section red hot may be performed by using a gas torch or a laser, but an electromagnetic induction coil is arranged in the branch pipe, and an alternating current is applied to the electromagnetic induction coil to apply an induction current to the pipe body. It is desirable to use an induction heating method in which the tube body is generated and heated. The induction heating method is an internal heating method and is capable of performing concentrated and uniform rapid heating at a required heating point. That is, the portion to be heated and the portion not to be heated can be clearly defined, and it is suitable for causing the tensile yielding in the present invention to specify the portion and cause it in a desired form. or,
It has excellent work efficiency and can easily handle small diameter pipes. A guideline for heating conditions is, for example, 25.4 mmφ x 2.6.
When heating a 3 mm section of a steel tube of mmt to 1000 ° C., it is about 15 kW × 20 sec.

According to the above-mentioned method, the tensile yielding in the narrow section is performed.
The operation is intermittently performed by changing the position.
It is also possible to carry out continuously. That is, as shown in FIG. 3, in a state in which a tensile force is constantly applied to the pipe expansion portion 3b of the branch pipe 3, for example, a narrow width section in a state where a tensile force in the direction of arrow A is applied to the pipe end. 3p is made to red heat in an annular shape by heating from inside the branch pipe 3, and the red heat position is continuously moved in the pipe axis direction. Here, the temperature rising speed and the moving speed of the narrow width section 3p that makes the ring red hot,
By setting the tensile force acting on it appropriately.
The red-heated section 3p continuously moves in the axial direction of the tube and the red-heated section continuously undergoes tensile yielding, and eventually the diameter reduction due to tensile yielding occurs over the desired section of the pipe expanding portion 3b. It can be carried out. In this case, since the movement is continuous, tensile yielding occurs smoothly over the entire section.

In this method, the width of the narrow width section 3p which is red-heated in an annular shape is such that the tensile yielding is stably generated in a narrow width, and the portion where the tensile yielding is finished does not cause further tensile yielding due to residual heat. The thickness of the branch pipe is 1 to 5 times the thickness of the branch pipe, although it should be set experimentally according to the situation.

[0025] Also Oite to this method, the position and or direction exerts a tensile force, the moving direction of the narrow section 3p was red-hot, the
This is similar to the case where the positions are sequentially changed . For example, as shown in FIG. 3, when a tensile force in the direction of arrow A is applied to the tip end of the branch pipe 3, the narrow red section 3p that annularly heats is branched. 3 is preferably moved to the rear end side. Similarly, the red heat temperature for tensile yield is 700 to 1100 °.
C, preferably about 900 to 1100 ° C. The tensile force applied to the branch pipe 3 in the pipe axial direction regulates the stress.
May be added, it may be added to regulate the pulling speed,
The stress regulation method is more advantageous in terms of preventing breakage or in terms of equipment technology. In order to proceed with a constant tensile yielding, it is usually sufficient to apply a constant tensile force, and a suitable range of tension is generally in the range of 5 to 50 MPa, although it varies depending on the material and the red heat temperature. The tensile force may be applied by detecting the displacement velocity of the pipe in the pipe axis direction due to tensile yielding and feeding back this. The moving speed of the red hot position in the tube axis direction is usually constant, but it may be changed such that the moving speed is reduced at a portion where the diameter reduction is desired to be locally increased.

The heating for making the narrow section 3p red hot,
Similar to the case of sequentially changing the position, it may be performed by using a gas torch or laser, but an electromagnetic induction coil is placed in the branch pipe and an induction current is generated in the pipe body by applying an alternating current to this. It is desirable to use an induction heating method for heating the tubular body by heating. A guideline for heating conditions is, for example, 25.4 mmφ
× 3mm section of 2.6mmt steel pipe 3mm / sec
It is about 20 kW when heated to 1000 ° C. at the moving speed. Reduce the diameter while moving the red hot position continuously
In this case, in order to rapidly cool the tensile-yield region, cooling air may be flown in the branch pipe 3.

The pipe expanding portion 3 of the branch pipe 3 is subjected to the above-described diameter reduction method.
By applying it to b, a large diameter reduction of up to 10% can be realized in one operation. This diameter reduction method may be applied repeatedly to one diameter reduction target portion twice or more depending on the situation. Also, depending on how the expanded diameter portions 3c and 3d are generated, or
In the case where it is difficult to apply a tensile force to the annularly heated section, as in the case where a plurality of locking grooves 4 are provided and the corresponding enlarged diameter portions 3e are formed in a plurality of steps, in advance, Applying the conventional heat reduction operation to the insertion part of the branch pipe to cause some rattling, and then to that part
The diameter methods may be attempted to smooth the application to tensioned.

[0028]

The above-described condensation radial direction method as above mentioned, it is possible to reduce the diameter of the desired portion of the pipe expanding section securing the branch pipe to the tube support plate, the enlarged diameter portion 3c, 3d, 3e It is possible to highly reduce the diameter of the pipe expanding portion 3b including the pipe to a level where it can be freely moved in the pipe axial direction with respect to the hole 2 formed in the pipe supporting plate 1. Therefore, applying this diameter reduction method,
For example, the branch pipe 3 can be easily removed from the pipe support plate 1 by reducing the diameter of the pipe expanding portion 3b as shown in FIGS. 1 to 3 and then pulling out that portion in the direction of arrow A or B. .

By the way, some branch pipes may have a flared portion at the end of the pipe, and the flared portion may be an obstacle during drawing after the diameter reduction. In that case, when the diameter of the pipe expanding portion is reduced by the method shown in FIG. 1 or 3, the flared portion 3f is largely pulled out from the front surface of the pipe support plate 1 as shown in FIG. Therefore, in that state, the flared portion 3f may be cut and removed or shaped so that it can pass through the hole 2 of the pipe support plate 1 and then the branch pipe may be pulled out in the direction of arrow B. In this case, since the flared portion 3f is largely separated from the front surface of the tube supporting plate 1, the cutting and removing operation or the shaping operation of the flared portion 3f can be easily performed without damaging the tube supporting plate 1.

Further, in FIG. 5, it is desired to pull out the pipe expanding portion 3b to which the diameter reducing operation is applied in the direction of the arrow A, but there are cases where the entire length of the branch pipe 3 cannot be pulled out in the direction of the arrow A. In that case, after cutting the middle part of the branch pipe 3, the branch pipe may be pulled out from the pipe support plate and removed. The disconnection at this time is
If the cutting position can be approached from the outside, the cutting may be carried out by fusing from the outer surface with a gas torch or the like. However, the applicant of the present invention previously filed Japanese Patent Application No. 7-2.
1173 (JP-A-8-192373) (method and apparatus for removing branch pipes), it is preferable to employ a method of causing a tubular body to red-heat and pull and break. As shown in FIG. 5, the cutting method is to position the electromagnetic induction coil 11 inside the section 3q of the branch pipe 3 to be cut, and to heat the section 3q in a ring-shaped manner. A tensile force in the direction is applied to cause tensile rupture. At the time of this tensile rupture, since the ruptured section 3q ruptures while reducing the diameter, there is no occurrence of burrs that tend to occur at the time of fusing by the gas torch. Can be pulled out from.

The present invention applies the above-described diameter reduction method to the diameter reduction of a branch pipe whose both ends are expanded and fixed to a pair of pipe support plates which are arranged facing each other at a distance.
Yes, and will be described in detail below .

FIG . 6 shows a specific example of the diameter reducing method according to claim 1.
It is shown . In FIG. 6, the left end of the branch pipe 3 is the C end,
The right end is the D end. First, as shown in FIG. 6A, C
Performs the diameter reduction operation of the pipe expansion part on the end side. This diameter reduction operation on the C end side is performed by applying a pulling force in the direction indicated by the arrow A to the pipe end on the C end side, and performing annular red heating operation on the heating means 12 such as an electromagnetic induction coil on the C end side. It is carried out by inserting the heating means 12 into the branch pipe 3 from the above, and moving the heating means 12 so as to move from the C end side to the D end side of the C-end side pipe expanding portion. As a result, the pipe expanding portion on the C end side is sequentially pulled and yielded from the C end side toward the D end side to reduce the diameter. The movement of the tensile yield section (that is, the movement of the heating means 12) at this time may be sequential or continuous.

Next, as shown in FIG. 6 (b), the diameter of the pipe expanding portion on the D end side is reduced by the operation from the D end side to the C
The operation on the end side is performed by turning it over to the D end side and adding it in a replaced form. That is, the heating means 12 such as an electromagnetic induction coil is inserted into the branch pipe 3 from the D end side in the form of applying a pulling force in the direction indicated by the arrow B to the pipe end on the D end side and performing annular red heat operation. The heating means 12 is added in a form of moving from the D end side to the C end side of the pipe expanding portion on the D end side. As a result, the pipe expanding portion on the D end side is sequentially pulled and yielded from the D end side toward the C end side to reduce the diameter.
The movement of the tensile yield section at this time may be sequential or continuous.

As described above, the diameter of each of the C-end side and D-end side expanded portions can be reduced, and then the branch pipe 3 is pulled out to the C-end side or the D-end side and removed. It should be noted that, at the time of this withdrawal and removal, there may be a case where there is a flared portion at the pipe end or there is a small diameter expansion portion that cannot be pulled out. In that case, prior to the drawing, the flared portion or the enlarged diameter portion of one of the pipe ends is cut or removed, or shaped so that it can pass through the hole of the pipe support plate 1, and pulled to the opposite side. You can get out. Alternatively, a method may be adopted in which the branch pipe 3 is cut between the pair of pipe support plates 1 by, for example, the method shown in FIG. 5 and pulled out to both sides.

FIG. 7 shows a concrete example of the diameter reducing method according to claim 2 .
It is shown . Also in the method shown in FIG. 7, first, C
The diameter reducing operation of the pipe expanding portion on the end side is performed as in the case of FIG. That is, as shown in FIG. 7A, a tensile force in the direction indicated by the arrow A is applied to the pipe end on the C end side, and
For annular red heat operation, the heating means 12 such as an electromagnetic induction coil
It is carried out by inserting the heating means 12 from the end side into the branch pipe 3 and moving the heating means 12 so as to move from the C end side to the D end side of the C-end side pipe expanding portion. As a result, the pipe expanding portion on the C end side is sequentially pulled and yielded from the C end side toward the D end side to reduce the diameter. In addition, the movement of the tensile yield section at this time (immediately
The movement of the heating means 12) may be sequential or continuous.

Next, the diameter of the pipe expanding portion on the D end side is reduced.
When performing this diameter reduction operation, as shown in FIG.
Inserting the heating means 12 such as an electromagnetic induction coil into the branch pipe 3 from the D end side in the form of applying a pulling force in the direction indicated by the arrow A to the pipe end on the C end side and performing annular red heat operation, This is performed by adding the heating means 12 in a form of moving from the C end side to the D end side of the pipe expanding portion on the D end side. This gives D
The pipe-expanded portion on the end side is sequentially pulled and yielded from the C end side to the D end side to reduce the diameter. The movement of the tensile yield section at this time may be sequential or continuous.

As described above, it is possible to reduce the diameters of the C-end side and D-end side expanded pipe processing portions, and it is possible to remove the branch pipe 3 as it is by pulling it to the C end side. Even in this case, the branch pipe may be pulled out to the D end side after the diameter reducing operation. Further, when the branch pipe is pulled out, as described above, the flared portion or the enlarged diameter portion of one pipe end is cut off or shaped, or the branch pipe 3 is inserted between the pair of pipe support plates 1. A method involving an operation such as cutting may be adopted.

In the method described with reference to FIGS. 6 and 7, the diameter of the expanded pipes at both ends of the branch pipe 3 is reduced, and then the branch pipe 3 is pulled out from the pipe support plate 1. It is also possible to partially change the order. FIG. 8 shows an example in that case. First, as shown in FIG.
The diameter reducing operation of the pipe expanding portion on the C end side is performed in the same manner as in the case of FIG. That is, a heating means 12 such as an electromagnetic induction coil is inserted into the branch pipe 3 from the C end side in a manner of applying a tensile force in the direction indicated by the arrow A to the pipe end on the C end side and performing an annular red heating operation. The heating means 12 is added in a form of moving from the C end side to the D end side of the C end side pipe expanding portion. As a result, the pipe expanding portion on the C end side is sequentially pulled and yielded from the C end side toward the D end side to reduce the diameter. The movement of the tensile yield section at this time may be sequential or continuous.

Next, as shown in FIG. 8 (b), after the rear end portion 3q of the pipe expanding portion 3b on the C end side is red-heated to reduce its diameter, heating of the portion 3q is continued to bring it into a red-hot state. With the state kept, the tensile force in the direction of arrow A is continuously applied to the pipe end. As a result, as shown in FIG. 8C, the portion 3g yields and breaks, and the C end side of the branch pipe 3 is pulled out from the pipe support plate 1.
Then, the diameter of the pipe expansion portion on the D end side is reduced in the same manner as the operation on the C end side, and after the diameter reduction, it can be pulled out and removed to the D end side.

In each of the above explanations, the branch pipe 3 is attached to the pipe support plate 1 with its end projecting, but the present invention is not limited to this. The present invention is not limited to this, and can be applied to a case where the end portion of the branch pipe 3 is fixed to the outer surface of the pipe support plate 1 at substantially the same position.

[0042]

According to the method of claim 1, the branch pipe is expanded.
Only the narrow section in the work section is red-heated and the tensile force is applied to that section.
Narrow width area that makes the operation of pulling and yielding red heat
The space from one end to the other end of the pipe expansion
Due to the configuration of adding in the form of continuous movement
The pipe-expanded part to be fractured due to local yielding.
It is possible to reduce the diameter to as high as 10%.
It Then, perform this diameter reduction operation on both ends of C and D respectively.
When applying to a branch pipe expanded and fixed to the support plate, first, C
Reduce the diameter of the pipe expansion part on the end side and apply tensile force to the pipe end on the C end side.
Inserted into the tube, in a form to be used, and an annular red heat operation
Aim the heating means from the C end side of the C end side pipe expanding part to the D end side.
Add by moving, then D end
By reducing the diameter of the side pipe expansion part from the D end side,
Add the operation of the C end by flipping it over to the D end and replacing it.
Both ends of C and D
It is possible to highly reduce the diameter of the pipe expanding portion.

According to the method of claim 2, the branch pipe is expanded.
Only the narrow section in the pipe processing section is red-heated and pulled to that section.
The operation of applying a force to cause tensile yield is narrowed by red heat.
The width section is gradually or gradually changed from one end side of the pipe expansion part to the other end side.
Or because it is configured to be added by moving continuously.
Causes the pipe expansion part to break due to local yielding.
It is possible to reduce the diameter to a level as high as 10% without
Wear. Then, this diameter reduction operation is performed on both ends of C and D respectively.
When applying to a branch pipe expanded and fixed to the pipe support plate, first,
Reduce the diameter of the expanded portion on the C end side and apply tensile force to the pipe end on the C end side.
Insert the ring-shaped incandescent operation into the tube
The heating means from the C end side of the C end side pipe expansion processing section to the D end side.
It is done by adding in a moving manner, then D
Reduce the diameter of the pipe expansion part on the end side and apply tensile force to the pipe end on the C end side.
Inserted into the tube, in a form to be used, and an annular red heat operation
Aim the heating means from the C end side of the D end side pipe expansion processing part to the D end side.
It was configured to be added by moving it
It is possible to reduce the diameters of the expanded pipes at both ends of C and D to a high degree.
You can

According to the method of claim 3, at a distance.
Insert and expand both ends of C and D into the pair of arranged pipe support plates.
The method according to claim 1 or 2 is applied to a branch pipe fixed to a pipe.
To reduce the diameter of the expanded pipes at both ends, and then support the branch pipe.
With the configuration that it is pulled out from the holding plate and removed,
After highly reducing the diameter of the expanded pipes at both ends of C and D, branch pipes
Can be pulled out, making it easy to pull out and remove the branch pipe
Can be carried out . In the method according to claim 4, the distance is reduced.
Both ends of C and D are inserted into a pair of pipe support plates arranged as
A branch pipe that has been expanded and fixed by flaring the end of the pipe
Pipe expansion at both ends by applying the method according to claim 1 or 2.
Part, then at least one flared part
So that it can be cut and removed or passed through the hole in the tube support plate.
After shaping, remove the branch pipe by pulling it from the pipe support plate.
Due to the configuration, the branch pipe with the flare processing part
It can be easily pulled out and removed. Where the pipe expansion
The tensile yielding operation is added during the diameter reduction operation of the work section.
This creates a length margin in the branch pipe, and the flared portion supports the pipe.
It has been pulled out of the board, so
Processing such as cutting removal or shaping processing of the processed part from the past
Even much easier to do. Claim 5
In the method, a pair of tube support plates arranged at a distance,
Both ends of C and D are inserted, the pipe is expanded, and the pipe end is flared.
The method according to claim 1 or 2 is applied to the branch pipe fixed by
To reduce the diameter of the expanded pipes at both ends, and then
After cutting the middle part, pull out the branch pipe from the pipe support plate
By removing the flare processing part,
Or, the process to shape it so that it can pass through the hole in the tube support plate
It is necessary to pull out and remove the branch pipe equipped with the flare processing part.
It is easy to carry out .

[0045]

Example 1 As shown in FIG. 9, 25.4 mmφ × is formed in a hole 2 having an inner diameter of 25.65 mm formed in a tube support plate 1 having a thickness of 100 mm.
Insert the branch pipe 3 (material STB340) of 2.6 mmt,
A sample was prepared which was expanded and fixed. Here, the expanded diameter portions 3c, 3d, 3e are formed on the outer surface of the pipe expansion portion 3b, and the outer diameter thereof is larger than the inner diameter of the hole 2 by about 2%. A jig 15 for applying a tensile force to the end of the branch pipe 3 is fixed by brazing, and a hydraulic cylinder (not shown) is connected to the jig 15 to apply a tensile force in the direction of arrow A. And Further, the electromagnetic induction coil 16 (width 30 mm) was inserted into the branch pipe 3 so that the branch pipe 3 could be heated annularly.
The right end of the branch pipe 3 is free.

In this state, first, the electromagnetic induction coil 16 is stopped at a position substantially equal to the outer surface of the tube support plate 1 (position shown in the figure), and heating is performed for 15 kW × 20 sec, whereby the section 3r of about 15 mm width becomes red heat. It became a state. Then
A tensile force was applied to the jig 15 so that a tensile stress of 10 MPa was applied to the red hot zone, and the red hot zone 3r was pulled and yielded. Since the jig 15 is displaced along with this tensile yielding, the tensile force application was stopped when the displacement reached about 1 mm. Next, the induction heating coil 16 was moved in the pipe axis direction by an amount substantially equal to the previous heating width (width of the red-hot section) and stopped, and the same operation as above was performed at that position to perform tensile yielding. Hereinafter, the same operation is sequentially carried out in the pipe axis direction, and finally, the expanded pipe portion 3d generated on the right side of the pipe support plate 1 is red-heated and tensile yielded. Since it became movable in the direction of arrow A with respect to 1, the operation was stopped and the branch pipe 3 was pulled out in the direction of arrow A. When the outer diameter of the reduced diameter portion of the pulled-out branch pipe 3 was measured, the outer diameter of the portion tightly adhered to the hole 2 was 24.8 mm,
The outer diameter of the enlarged diameter portion 3e was 25.5 mm, which was considerably smaller than the inner diameter of the hole 2.

Example 2 As shown in FIG. 10, a hole 2 having an inner diameter of 51.4 mm formed in a tube support plate 1 having a thickness of 60 mm was inserted into a hole of 50.8 mmφ × 5.
A 3 mmt branch pipe 3 (material STB340) was inserted, expanded and fixed, and the tip was flared to prepare a sample. Here, on the outer surface of the pipe expanding portion 3b, the expanded diameter portion 3d is formed.
The outer diameter was about 5% larger than the inner diameter of the hole 2. In order to apply a tensile force to the pipe end of the branch pipe 3, a clamp jig 17 is attached to the flared processing portion 3f at the tip, and a hydraulic cylinder (not shown) is attached to the clamp jig 17.
It was made possible to apply a pulling force in the direction of arrow A by connecting. Further, the electromagnetic induction coil 18 (width 20 mm) was inserted into the branch pipe 3 so that the branch pipe 3 could be heated annularly. Further, the right end of the branch pipe 3 was fixed with a jig (not shown).

In this state, in the same manner as in Example 1, red heat and tensile yielding operations were sequentially carried out in the tube axis direction. The heating power and time in each operation are 25 kW × 15 sec, the heating width (red heating width) is about 10 mm, the moving pitch of the electromagnetic induction coil 18 is 10 mm, the applied tensile stress is 150 MPa,
The displacement amount is 1.7 mm. This operation was carried out up to the right expanded portion 3d of the tube support plate 1 to stop the diameter reducing operation. At this time, since the root of the flared portion 3f extends about 10 mm from the left surface of the tube support plate 1, the flared portion 3f is removed by cutting that portion, and then the branch pipe 3
The branch pipe 3 can be easily pulled by pulling the pipe to the right.
I was able to pull it out. When the outer diameter of the reduced diameter portion of the extracted branch pipe 3 was measured, the outer diameter was 49.1 mm, which was considerably smaller than the inner diameter of the hole 2.

Example 3 The same sample as in Example 1 was prepared, and 10 MPa was applied to the tube end.
With the tensile force continuously applied, a width of 3
With the electromagnetic induction coil of 0 mm inserted and the electromagnetic induction coil being energized with 20 kW, the moving speed is 3 mm / s.
At ec, the branch pipe was moved from the front end side toward the rear end side. As a result, a red hot zone having a width of about 10 mm was generated and continuously moved, and tensile yielding was continuously generated in the red hot zone. When the electromagnetic induction coil passed through the enlarged diameter portion 3d (see FIG. 9) on the rear end side of the branch pipe, the branch pipe became movable in the tip direction of the branch pipe with respect to the pipe support plate. It stopped and the branch pipe was pulled out to the front direction. When the outer diameter of the reduced diameter portion of the extracted branch pipe was measured, the outer diameter of the portion that was tightly attached inside the hole was 24.8 mm, and the outer diameter of the enlarged diameter portion 3e (see FIG. 9) was 2
The diameter was 5.5 mm, which was considerably smaller than the inner diameter of the hole.

Example 4 The same sample as in Example 2 was prepared, and 150MP was added to the tube end.
While continuously applying the tensile force of a, an electromagnetic induction coil with a width of 20 mm was inserted into the branch pipe, and the electromagnetic induction coil was energized at 25 kW, and the moving speed was 3 mm /
In sec, the branch pipe was moved from the front end side toward the rear end side.
As a result, a red hot zone having a width of about 6 mm was generated and continuously moved, and tensile yielding was continuously generated in the red hot zone. When the electromagnetic induction coil passes through the expanded diameter portion 3d (see FIG. 9) on the rear end side of the branch pipe, the work is stopped, the flared portion at the tip is cut and removed, and then the branch pipe is pulled toward the rear end. And pulled out from the tube support plate. When the outer diameter of the reduced diameter portion of the extracted branch pipe was measured, the outer diameter was 49.1 mm, which was considerably smaller than the inner diameter of the hole.

[0051]

As is apparent from the above description , according to the invention described in claims 1 and 2 of the present application , it is arranged at a distance.
Insert the both ends of C and D into the pair of pipe support plates
Highly reduce the diameter of the expanded pipes at both ends of the specified branch pipe
It has the effect of being able to.

According to the invention described in claims 3 to 5,
Both ends of C and D are attached to a pair of pipe support plates arranged at a distance.
Part of the branch pipe that has been expanded and fixed.
The effect is that the diameter can be reduced to a high degree and it can be easily pulled out and removed.
It has fruits .

[0053]

Further, according to the present invention, the following effects can be obtained. 1) Branch pipes expanded and fixed with various specifications such as heat exchangers, smoke pipe boilers, and water pipe boilers can be removed according to a certain policy. 2) The efficiency of removal work is greatly improved. 3) It is easy to remove some branch pipes for inspection. 4) Since no troubles such as damage to the pipe support plate or breakage of the branch pipe being removed do not occur during the removal work, involuntary repair and restoration work is eliminated.

The removal of the branch pipe is carried out in order to maintain the above-mentioned high heat equipment from the viewpoint of safety and economy, and the contribution by the fact that the present invention enables the removal work to be performed efficiently and reliably large.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an example of a method for reducing the diameter of a branch pipe used in the present invention .

FIG. 2 is a schematic cross-sectional view showing another example of the branch pipe diameter reducing method used in the present invention .

FIG. 3 is a schematic sectional view showing still another example of the method for reducing the diameter of a branch pipe used in the present invention .

Figure 4 is a schematic sectional view showing a branch pipe and tube support plates after the reduced diameter

[5] After the reduced diameter, schematic sectional view showing an operation of cutting the branch pipe

FIG. 6 is a schematic cross-sectional view showing an example of an operation of reducing the diameter of both ends of a branch pipe provided by fixing both ends to a pair of pipe support plates by applying the invention of claim 1 .

FIG. 7 is a schematic cross-sectional view showing another example of the operation of reducing the diameter of both ends of a branch pipe provided by fixing the both ends to a pair of pipe support plates by applying the invention of claim 2 .

FIG. 8 is a schematic cross-sectional view showing still another example of the operation of reducing the diameter of both ends of a branch pipe provided by fixing both ends to a pair of pipe support plates by applying the invention of claim 1;

FIG. 9 is a schematic sectional view illustrating the first embodiment.

FIG. 10 is a schematic sectional view illustrating a second embodiment.

FIG. 11 is a schematic cross-sectional view showing an example of a structure for fixing a branch pipe to a pipe support plate.

FIG. 12 is a schematic cross-sectional view showing another example of the structure for fixing the branch pipe to the pipe support plate.

[Explanation of symbols]

1 tube support plate 2 holes 3 branches 3a insertion part 3b Pipe expansion part 3c, 3d, 3e Expanding part 3f flare processing section 3g, 3h ... 3n narrow section 3p narrow section 4 locking groove 11, 16, 18 Electromagnetic induction coil 12 Heating means 15 jigs 17 Clamp jig

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Makoto Kumakawa 2-17-8 Tonomachi, Kawasaki-ku, Kanagawa Prefecture Dai-ichi Kogyo Kogyo Co., Ltd. (72) Inventor Masanori Terasaki 2-chome, Tonomachi, Kawasaki-ku, Kanagawa Prefecture No. 17 No. 8 Daiichi Kogyo Kogyo Co., Ltd. (56) Reference JP 5-337750 (JP, A) JP 4-22094 (JP, A) JP 55-60184 (JP, A) Kai 63-63522 (JP, A) JP 60-146632 (JP, A) JP 63-38803 (JP, A) JP 61-213404 (JP, A) JP 8-192373 ( JP, A) JP 56-71702 (JP, A) JP 1-118308 (JP, A) JP 63-242429 (JP, A) Actually open 7-33538 (JP, U) Actually open Sho 60-86708 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B23P 19/00 -21/00 F22B 37/58 F16L 1 / 00,5 / 00

Claims (5)

(57) [Claims] 1. A pair of tube support plates spaced apart from each other.
Of the branch pipe with both ends of C and D inserted and expanded and fixed,
For the pipe expansion parts at both ends, the narrow section within the pipe expansion part
The inside of the branch pipe is heated by a ring to make it red hot, and
Tensile by applying a tensile force in the direction of the pipe axis to the section that glows red like
To yield and reduce diameter Apply the diameter reduction method to reduce diameter
In the method , first, the diameter reduction of the pipe expansion processing portion on the C end side is performed by pulling the pipe.
In a form in which a tensile force is applied to the pipe end on the C end side, and
The heating means inserted into the tube is used to expand
Add in the form of moving from the C end side of the work part to the D end side.
With, the pipe expansion part on the C end side is changed from the C end side to the D end side.
Then, the pipe is machined from the D end side by reducing the diameter of the pipe expansion portion on the D end side.
Depending on the work, the operation on the C end side is turned over to the D end side and replaced.
By adding in the form, the pipe expansion part on the D end side can be
It is characterized by performing tensile yielding from the end side to the C end side in order to reduce the diameters of the pipe expanding portions at both ends of C and D.
Branch tube diameter reduction method . 2. A pair of tube support plates arranged at a distance.
Of the branch pipe with both ends of C and D inserted and expanded and fixed,
For the pipe expansion parts at both ends, the narrow section within the pipe expansion part
The inside of the branch pipe is heated by a ring to make it red hot, and
Tensile by applying a tensile force in the direction of the pipe axis to the section that glows red like
To yield and reduce diameter Apply the diameter reduction method to reduce diameter
In the method , first, the diameter reduction of the pipe expansion processing portion on the C end side is performed by pulling the pipe.
In a form in which a tensile force is applied to the pipe end on the C end side, and
The heating means inserted into the tube is used to expand
Add in the form of moving from the C end side of the work part to the D end side.
With, the pipe expansion part on the C end side is changed from the C end side to the D end side.
And then yielding to each other in order, and then reducing the diameter of the expanded portion on the D end side to the pipe end on the C end side.
Applying a pulling force and applying a heating means to the D end side pipe
Add in the form of moving from the C end side of the work part toward the D end side
By doing so, the pipe expansion part on the D end side is changed from the C end side to the D end side.
It is characterized in that the pipe expansion processing parts at both ends of C and D are reduced in diameter by performing tensile yielding in order.
Branch tube diameter reduction method . 3. A pair of tube support plates arranged at a distance.
A branch pipe having both ends C and D inserted and expanded and fixed.
Apply the method described in 1 or 2 to shrink the pipe expansion parts at both ends.
And then remove the branch by pulling it out of the tube support plate.
A method for removing a branch pipe, which is characterized in that 4. A pair of tube support plates spaced apart from each other.
Insert both ends of C and D into the tube, expand the tube, and flare the tube end.
The method according to claim 1 or 2, wherein the branch pipe is processed and fixed.
To reduce the diameter of the pipe expansion parts at both ends, and then
Cutting and removing at least one flared portion or the pipe support plate
After shaping it so that it can pass through the holes of the
Branch pipe removal characterized by pulling out and removing it from the holding plate
How to leave . 5. A pair of tube support plates arranged at a distance.
Insert both ends of C and D into the tube, expand the tube, and flare the tube end.
The method according to claim 1 or 2, wherein the branch pipe is processed and fixed.
To reduce the diameter of the expanded pipes at both ends, and then
After cutting the middle part of the pipe, pull out the branch pipe from the pipe support plate.
A method of removing a branch pipe characterized by removing the branch pipe .