JP4348777B2 - Production method of different diameter miter bend - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a miter bend of different diameters used for connection at a predetermined butt angle with different diameters in plant piping and ducts.
[0002]
[Prior art]
Conventionally, in plant piping, ducts and the like, pipes are connected to each other at a predetermined butting angle using an elbow or the like, but there are cases where it is inevitably desired to change the diameter at the bent portion due to space constraints.
[0003]
Thus, when it is necessary to connect the ends of two pipes having different butting angles and different diameters, it is not easy to define the shape and structure of a component that changes its diameter while bending, In addition, since it was difficult to manufacture the parts, the diameter was changed using a reducer in the straight pipe portion after the angle was changed by the elbow having the same diameter.
[0004]
For example, FIG. 5 shows an example of a bent portion of a pipe. When the pipe 9 having the outer diameter D1 and the pipe 10 having the outer diameter Ds, which have different angles as described above, are connected, the same diameter as that of the D1 is used. The elbow 11 having De and the reducer 12 were combined.
[0005]
However, as shown in FIG. 5, in the case of a pipe combining an elbow and a reducer, there is a possibility that the throttle part of the reducer may be worn when used in a device that flows a wearable catalyst such as silica / alumina. -There has been a demand for a method for easily producing a miter bend with a different diameter that can smoothly flow the catalyst by changing the diameter while bending the bent portion of the ducts.
[0006]
Therefore, as a method of manufacturing parts that connect pipes with different angles and diameters, a method of manufacturing smooth bends of different diameters by welding pipes that were manufactured in half by pressing, and calculating from the shape of the bent pipe. Then, there is a method of manufacturing a plurality of plate materials, rounding and welding the plate materials in a circular shape, and connecting them together to manufacture a miter bend having a different diameter.
[0007]
[Problems to be solved by the invention]
However, in the production by the press method, it is possible to produce a smooth bend that changes the diameter while turning smoothly, but there are many large pipes with a diameter of about 1 m in plant piping, etc., and the die cost is very high It became expensive, and there was a problem in cost.
[0008]
In addition, the method of connecting the rounded and welded plate materials is because the plate materials are rolled and welded one by one, so the workability is poor and the definition of the size and shape of the plate material becomes very complicated, Due to cost problems, it is almost unused.
[0009]
Therefore, an object of the present invention is to provide a method for manufacturing a mitered bend of different diameters that solves the above-described problems, has good workability, is easy to define dimensions and shapes, and can be reduced in cost. .
[0010]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the invention according to claim 1 is a method of manufacturing different diameter miter bends in which end portions of pipes having different butting angles and different diameters are connected with a predetermined curvature. Conical pipes with large and small diameters matched to different pipes and having a height approximately equal to the connection distance along the curvature of the center of the pipes are manufactured, and the conical pipes are alternately staggered at a predetermined angle. A split ring member is cut, and the split ring members are alternately inverted by 180 ° and connected, and the split rings are welded so as to have the predetermined curvature. It is a production method.
[0011]
According to a second aspect of the present invention, the cut surface of the split ring member is an angle that is ½ of the angle obtained by dividing the angle α by the number of cuts n, where α is the bending angle between the pipes and n is the number of cuts. The method for producing a different-diameter miter bend according to claim 1, which is alternately cut at (± θ).
[0012]
In the invention of claim 3, the height h of the center portion of the split ring member excluding both ends is set to a value obtained by dividing the height H of the conical pipe by the number of times of cutting n, and the centers of the split ring members at the upper and lower ends The height of the part is the manufacturing method of the different diameter miter bend according to claim 1 or 2, which is formed at h / 2.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
A preferred embodiment of the present invention will be described with reference to the accompanying drawings.
[0014]
FIG. 1 shows a state in which pipes 7 and 8 having different butt angles and different diameters are connected to each other using the different-diameter miter bend 1 manufactured by the method of the present invention.
[0015]
In FIG. 1, the pipe 7 has an outer diameter DL of, for example, 1746 mm, and the other pipe 8 has an outer diameter of, for example, 1346 mm, and an angle formed by lines l ₇ and l ₈ connecting the end faces of these pipes 7 and ₈ . α is, for example, 45 °, and the different-diameter miter bend 1 that connects the end faces of the pipes 7 and 8 is constituted by divided ring members P1 to P6 formed by dividing the angle α into six parts. The split ring members P <b> 1 to P <b> 6 are sequentially connected along the curvature of the center between the eight and are formed so as to coincide with the connection distance L.
[0016]
First, the split ring member P1 connected to the large-diameter side pipe 7 is formed at the same end as the outer diameter DL on the large-diameter side, and the split ring member P6 connected to the small-diameter side pipe 8 is The diameter of the connecting end is formed to be the same as the outer diameter DS of the pipe 8 on the small diameter side, and the split ring members P1 and P6 have an angle θ (= 4.5 ° around the intersection of the lines l ₇ and l ₈ . ), And the intermediate divided ring members P2 to P5 are formed by successively reducing the diameter of the cone, and formed into a cone-shaped ring having an angle 2θ (= 9 °). Is done.
[0017]
Next, the manufacturing method of this different diameter miter bend 1 is demonstrated with reference to FIGS.
[0018]
First, as shown in FIG. 2, the conical pipe 2 is manufactured.
[0019]
The outer diameter Da on the large-diameter side of the conical pipe 2 is the same as the outer diameter DL of the large-diameter pipe 7 to be connected described in FIG. 1, and the small-diameter outer diameter Db is outside the small-diameter pipe 8. It is the same as the diameter DS.
[0020]
Further, the height H of the conical pipe 2 is formed to be substantially equal to the connection distance L along the curvature of the center of the pipes 7 and 8 to be connected as described in FIG.
[0021]
The conical pipe 2 can be manufactured relatively easily by a method of rounding a fan-shaped plate from a plate material and welding it into a conical shape.
[0022]
Now, the conical pipe 2 manufactured in this way is obliquely cut at a predetermined cutting interval (h, h / 2) and a predetermined cutting angle (θ) as shown by the cutting lines C1 to C5 shown by dotted lines in FIG. Then, the split ring members P1 to P6 are manufactured.
[0023]
In these divided ring members P1 to P6, when the value obtained by dividing the height H of the conical pipe 2 by the number of times of cutting n is h, the height of the central portion of the large diameter and small diameter divided ring members P1 and P6 is h / 2. The other intermediate divided ring members P2 to P5 are manufactured by being obliquely cut alternately at a position where the height of the central portion is h and at the angle θ.
[0024]
The cutting angle θ is set to an angle (± θ) that is ½ of an angle obtained by dividing the bending angle α of the pipes by the number of cuts n, that is, 2θ × n = α.
[0025]
In the present embodiment, the bending angle α between the pipes is 45 °, and if the conical pipe is cut n times, the cutting angle θ may be cut alternately at 4.5 °.
[0026]
The number of times of cutting n and the cutting angle θ are set to appropriate values according to the bending angle α and the difference between the outer diameters DL and DS of the large-diameter side pipe and the small-diameter side pipe. When smoothing is desired, the miter bend 1 can be made smoother by increasing the number of times of cutting n and decreasing the cutting angle θ.
[0027]
Next, the split ring members P1 to P6 manufactured by cutting as shown in FIG. 2 are inverted 180 degrees and connected to each other.
[0028]
That is, as shown in FIGS. 3 (a) and 3 (b), the point 3a having the lowest height on the cut surface 3 of the large-diameter-side split ring member P1 and the second-stage split ring member The split ring is such that the lowest point 4b is in contact with the cut surface 4 of P2, and the highest points 3b and 4a are in contact with the cut surfaces 3 and 4 of the split ring members P1 and P2. The member P2 is inverted 180 ° with respect to the split ring member P1, and the cut surface 3 of the split ring member P1 and the cut surface 4 of the split ring member P2 are welded.
[0029]
Next, a point 5b where the height is lowest at the cut surface 5 of the second-stage split ring member P2 and a point 6a where the height is lowest at the cut surface 6 of the third-stage split ring member P3 are as follows. The split ring member P3 is inverted 180 ° with respect to the split ring member P2 so that the highest points 5a and 6b are in contact with each other at the cut surfaces 5 and 6 of the split ring members P2 and P3. 5 and the cut surface 6 are welded.
[0030]
After that, the split ring members P4 to P6 are alternately reversed 180 ° and welded in the same manner, so that the bending is performed at a predetermined angle α and the diameter is gradually changed as shown in FIG. Diameter miter bend 1 can be manufactured.
[0031]
Since it is cut obliquely, the connecting surface does not become a perfect circle, but the deviation is minute and does not affect the welding.
[0032]
Further, different-diameter miter bends having various shapes can be obtained by arbitrarily changing the cutting angle θ and the number of times of cutting n.
[0033]
In the different-diameter miter bend 1 manufactured by this method, the centers of the large-diameter pipe 7 and the small-diameter pipe 8 are not the same, and a slight deviation occurs, but there is no problem in actual use.
[0034]
【The invention's effect】
As described in detail, according to the present invention, the following effects are exhibited.
[0035]
(1) The manufacturing work is easy, and the cost can be significantly reduced as compared with a manufacturing method using a press.
[0036]
(2) Since one conical pipe is cut, the diameters of the cross sections to be welded are the same, so that connection is easy.
[0037]
(3) The definition of the shape is very simple because it can be defined by 2θ × n = α, and various rounding angles and shapes can be made by arbitrarily changing the shape of the conical pipe, the cutting angle θ and the number of times of cutting n. Different diameter miter bends can be manufactured.
[0038]
(4) A conical pipe is produced by rounding a plate material that has been cut into a fan shape, and the conical pipe may be cut and alternately reversed and connected, and the work can be facilitated and the accuracy control thereof is easy.
[0039]
(5) Since the diameter can be changed smoothly, it is difficult to wear even if a wearable catalyst or the like is flowed.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of the present invention.
FIG. 2 is a view showing an example of a conical pipe used for manufacturing a different diameter miter bend in the present invention.
FIG. 3 is a view showing a state in which the conical pipe shown in FIG. 2 is cut and connected in the present invention.
FIG. 4 is a view showing an example of a different diameter miter bend manufactured by the manufacturing method of the present invention.
FIG. 5 is a view showing an example of a conventional pipe using a combination of an elbow having the same diameter and a reducer.
[Explanation of symbols]
1 Different diameter miter bend 2 Conical pipe θ Cutting angle α Bending angle

Claims (3)

In the manufacturing method of different-diameter miter bends in which the ends of pipes having different butting angles and different diameters are connected with a predetermined curvature, the pipes having different diameters have large and small diameters, and A conical pipe having a height substantially equal to the connection distance along the curvature of the center of the pipes is manufactured, and the conical pipes are alternately cut at a predetermined angle to form divided ring members, and the divided ring members are alternately arranged. A method of manufacturing a miter bend with different diameters, wherein the split rings are welded so as to have the predetermined curvature. The cut surfaces of the split ring members are staggered at an angle (± θ) that is ½ of the angle obtained by dividing the angle α by the number of cuts n, where α is the bending angle between the pipes and n is the number of cuts. The manufacturing method of the different diameter miter bend of Claim 1 cut | disconnected. The height h of the center portion of the split ring member excluding both ends is set to a value obtained by dividing the height H of the conical pipe by the number of times of cutting n, and the height of the center portion of the split ring members at the upper and lower ends is h. The manufacturing method of the different diameter miter bend of Claim 1 or 2 formed in / 2.

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