JPS6236770B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention is a silo. The present invention relates to a method of manufacturing a circumferential ring used in constructing a cylindrical storage tank such as a tank.

To explain the conventional method of constructing a cylindrical steel storage tank using a silo as an example, first, a cut plate is re-cut to the specified dimensions at a processing factory, and a groove is cut for on-site welding, and then the steel plate is The piece is curved into an arc shape that fits the circumferential surface of the silo's circumferential body (in-factory process). Next, a large number of curve-formed arc-shaped steel plate pieces are transported to the silo installation site, 3 to 6 pieces are placed firmly on the circumference on a vertical welding surface plate, and vertical welding is performed. form a ring. Therefore, 2 to 4 circumferential rings are stacked one after another on another surface plate, horizontally welded to form a cylindrical block, and this cylindrical block is lifted by a crane truck and stacked one after another at the silo construction site. The silo circumference is constructed by sequentially horizontally welding the block joints.

However, according to this conventional method, it takes a large amount of man-hours and expense to bend the cut plate pieces to a predetermined curvature in the factory process, and it is necessary to cut a bevel for welding for each cut plate piece. Preparatory work such as this requires significant time and expense. Furthermore, when forming a ring at the installation site, the number of vertical weld seams is equal to the number of curved steel plate pieces arranged on the circumference.
This required many welding processes and welding consumables. In addition, when there are many welded parts, inspection for welding defects is time-consuming, and defects tend to remain, resulting in many reliability problems. Furthermore, when bending a piece of steel to a constant curvature in a factory process, it is difficult to generate a bending moment at the edge of the cut plate, so there is a risk that a straight part will remain at the edge, and the curved steel plate piece may be bent into a ring shape. When vertically welding them side by side, the joint does not form a smooth curved surface and tends to form peaks.
In order to prevent this peaking as much as possible, it takes a considerable amount of time and effort to align the joints, and the presence of peaking also has the disadvantage of reducing welding strength when internal pressure is applied.

Therefore, the present inventor effectively utilized the continuity of the steel band coil, and while unwinding this coil, formed it into a curved steel plate with a predetermined curvature using a vertical bending machine, and It has been found that by cutting the ring at a length corresponding to the ring circumference and joining the cut end and the unrolled end, it is possible to easily manufacture a ring with only one vertical weld line. As a concrete measure, it is conceivable to use a ring forming apparatus as shown in FIG. That is, a steel strip coil 1 placed vertically on a rotary reel 2 is unwound, bent to a predetermined curvature using a vertical bending machine 3 (hereinafter referred to as a roll bender), and the weight of the formed curved steel plate 1a is reduced. By arranging the supporting horizontal rotating rollers 8 at intervals on the circumference of a predetermined radius, a bending moment that would affect the molding curvature is not generated at the bender exit point E. Although it is possible to continuously form a curved steel plate 1a with a predetermined curvature with this device,
When the predetermined ring circumference is obtained, roll bender 3
When the formed steel plate 1a is cut at the entry side of the ring, the bender 3 cannot apply an effective bend to the cut end, and the steel plate curvature near the cut end differs from the predetermined ring curvature. Peaking occurs during welding. On the other hand, when cutting the curved steel plate 1a on the exit side of the roll bender 3, the steel plate unwinding end A cannot obtain the predetermined ring circumference unless it enters the roll bender 3 again. A problem arises in that the steel strip and the unwinding end A of the steel strip overlap on the entry side of the bender 3. In order to avoid this, the curvature of the steel plate formed by the bender 3 is made smaller than the predetermined ring curvature (the radius of the formed curved steel plate is larger than the predetermined ring radius), and the curved steel plate when cut on the exit side of the bender 3 is There is also a method of making the circumference of 1a equal to the predetermined ring circumference, but in this method, the steel plate unwinding end A and the cut end are separated by a large distance, so when welding these ends to form a ring, a very large pull is required. This requires a lot of force and is technically difficult, and it is almost impossible to do this at the storage tank installation site.

This also applies to the case where the steel strip coil 1 is placed outside the ring forming part as shown in FIG. Therefore, as shown in FIG. 3, a movable roller 7a and a fixed roller 7b are provided in front of the entrance side of the bender 3 to correct the advancing direction of the steel sheet unwinding end A to the outside of the bender 3, and the unwinding end of the formed curved steel sheet 1a is After A passes the position of the movable roller 7a, the movable roller 7a is moved outward (in the direction of the arrow in the figure), and in cooperation with the fixed roller 7b, the curved steel plate 1a is bent within its elastic limit as shown by the dotted line. The above-mentioned problem can be solved by moving the molded curved steel plate 1a to the position shown by and cutting the formed curved steel plate 1a on the exit side of the bender 3 when a predetermined ring circumference is obtained. That is, the movable roller 7a for correcting the traveling direction is arranged vertically so that the unwinding end A touches the inside of the drawing trajectory arc even when no external force is applied to the curved steel plate 1a, and the point A is At an appropriate time after passing the roller 7a, the movable roller 7a is moved to the outward position shown by the dotted line. At this time, the profile of the curved steel plate 1a changes from the solid line to the dotted line.
When the ring is unwound to a length corresponding to the circumferential length of one ring, the unwinding end A is located outside the bender 3, and the problem of lapping at the entrance side of the bender does not occur. A bending moment is induced in the curved steel plate 1a by the movement of the movable roller 7a in the direction of the arrow in FIG.
If the amount of movement and the position of the fixed roller 7b are limited, the latent curvature at the time when the curve-formed steel plate 1a is extracted from the forming device after cutting the steel plate will be equal to the curvature achieved before moving the movable roller 7a. .
However, when the moving direction of the curved steel plate 1a is changed by moving the movable roller 7a, a bending moment is applied to point E on the exit side of the bender 3, so that the potential curvature of the curved steel plate released from the bender 3 is It is different from the potential curvature before movement in 7a. Therefore, if the bending moment induced at point E on the exit side of the bender is suppressed as much as possible, a uniform latent curvature can be obtained over the entire circumference of the curved steel plate 1a without particularly adjusting the bender 3. In the end, the formed curved steel plate 1a
When changing the direction of movement of the unwinding end A midway through, a moment is generated that suppresses the bending moment induced by the correction of the direction of movement and transmitted to point E on the bender exit side through the curved steel plate 1a. By appropriately disposing the damping propagation device between the movable roller 7a and the bender 3, and limiting the amount of movement of the movable roller 7a so that the change in curvature of the curved steel plate 1a between the roller position and the bender position is within the elastic range. got the idea for a new technology.

An embodiment of the ring manufacturing equipment of the present invention, which is suitable for realizing the above requirements, will be described with reference to FIG.
Reference numeral 1 denotes a steel strip coil placed on a rotating reel 2, and the steel strip coil unwound by the rotation of the reel is fed to a roll bender 3. This roll bender 3
As shown in FIG. 5, three sets of vertical rolls 3a, 3
b, 3c, 3d, 3e, 3f, 3 of which
a and 3e are fixed driving rolls; 3e and 3f are movable driving rolls that are pressed onto the fixed driving rolls 3a and 3e; and 3c and 3d are non-driving rolls that can move in the direction V in the figure. By appropriately adjusting the rolls, the steel strip 1 is curved to a predetermined curvature. Reference numeral 8 denotes a horizontal rotating roller, which is arranged at appropriate intervals on the circumference of a predetermined radius, and is used to roll the formed curved steel plate 1a released from the roll bender 3.
supports its own weight and guides it in the circumferential direction. 5, after the formed curved steel plate 1a is unrolled to a length sufficient for a predetermined ring circumference, the curved steel plate is cut near the exit side of the bender 3 and beveled for longitudinal welding. This is a cutting and beveling machine that performs. 4 is a beveling machine for ring stacking horizontal welding placed in front of this cutting beveling machine 5, which automatically cuts a bevel on the side edge of the curved steel plate 1a released from the roll bender 3. do. Reference numeral 10 denotes a dummy steel plate cutting machine disposed between the beveling machine 4 and the roll bender 3, which cuts the dummy steel plate welded to the tip of the coil when the steel strip coil 1 is first unwound. Reference numeral 6 denotes a moment attenuation propagation device that prevents the bending moment caused by the movement of the movable roller 7a from being transmitted to the exit side of the bender 3. Vertical roll 6
a and 6b, and a plurality of sets (three sets in this embodiment) are arranged at appropriate intervals on a predetermined circumference. Reference numeral 7 indicates a device for changing the advancing direction of the unwinding end of the steel plate, which is composed of a movable roller 7a and a fixed roller 7b.
By moving a in the direction shown by the illustrated arrow, the advancing direction of the steel plate unwinding end A is changed from the state shown by the solid line to the state shown by the dotted line within the elastic limit of the curved steel plate 1a.

Next, we will describe a method for manufacturing a circumferential ring for constructing a cylindrical storage tank using the above-mentioned apparatus. First, a steel strip coil 1 is loaded on the rotary reel 2, and a dummy steel plate (not shown) for unwinding the coil is installed. The dummy steel plate is loaded into the bender 3, and the rear end of this dummy steel plate and the tip of the coil are joined. Next, the roll bender 3 is driven to unwind the coil 1, and it stops when the joint between the dummy steel plate and the tip of the coil exits the bender 3, and the dummy steel plate is cut by the dummy steel plate cutting machine 10. Here, the central roll is set so that the curvature of the curved steel plate 1a discharged from the bender 3 becomes a predetermined value, and after this setting, it is unrolled until the part in contact with the central roll passes through the beveling machine 4, Stop. Here, a beveling machine 4 for horizontal welding and a roll bender 3
Bending and forming the steel strip and forming the curved steel plate 1
Carry out bevel cutting for horizontal welding to a for a short time,
This horizontal welding groove portion passes through the cutting bevel processing machine 5 and stops at an appropriate position, and the cutting bevel processing machine 5 cuts and removes the unstable curvature portion of the coil tip during bender adjustment. Form a groove for vertical welding at the end.

Next, the roll bender 3 and the beveling machine 4 are operated continuously, and while the coil strip steel plate 1 is continuously formed into a curved steel plate 1a having a predetermined curvature, a horizontal welding groove is formed on the side edge of this steel plate. Form continuously. During this time, the unwinding end A of the formed curved steel plate 1a passes through the moment damping transmission device 6, the horizontal rotating roller 8, etc. in a very natural state. Therefore, this curved steel plate 1a
When the unwinding end A passes the position of the movable roller 7a, the movable roller 7a is moved in the direction of the arrow shown in the figure, and the direction of movement is changed so that the unwinding end A is removed to the outside of the bender 3. At this time, a bending moment acts on the formed curved steel plate 1a, but since the curved steel plate is sandwiched between the rolls 6a and 6b of the moment attenuation transmission device 6 provided at an appropriate interval, the influence of the bending moment is reduced. There is no effect on the exit side of vendor 3.

In this way, the forming process is continued until the length of the curved steel plate 1a becomes long enough to take the predetermined ring circumference, and when the predetermined ring circumference is obtained, the unrolling and forming of the steel plate is stopped. Then, the position of the cutting bevel processing machine 5 is finely adjusted so that the length of the formed curved steel plate 1a is equal to the predetermined ring circumference, and the formed curved steel plate 1a is cut at that position. Thereafter, the cut curved steel plate 1a is lifted upward by a lifting device and removed from the forming device. At this time, the unwinding end A side of the curved steel plate 1a, whose direction of movement has been changed, returns to its original ring shape due to its elastic force, so this ring-shaped curved steel plate 1a is suspended on a surface plate, and the unwinding end A side of the curved steel plate 1a is If you butt the cut ends together and weld vertically,
It is possible to manufacture a circumferential ring with only one vertical weld line.

After manufacturing the first circumferential ring as described above, the coil steel plate is manufactured by repeating the same process as above without joining the dummy steel plate to manufacture the second, third, etc. rings. You can continue manufacturing one by one until you run out. When replacing the coil 1, either return to the first ring manufacturing method described above and start forming by inserting a dummy steel plate, or start forming by welding and joining the remaining coil and the replacement coil. The circumferential ring is manufactured in the same manner as described above. In addition, in the above-mentioned embodiment, a case was described in which the direction of movement was changed by applying an external force so that the unwinding end A of the formed curved steel plate 1a would come off to the outside of the bending machine (roll bender) 3, As shown in FIG. 2, when the steel sheet 1a is placed outside the ring forming part, an external force within the elastic limit is applied so that the unwinding end A of the forming curved steel sheet 1a comes off inside the bending machine 3. A method is adopted in which the advancing direction of the unwinding end A of the steel plate on the way is changed to the inside of the forming machine.

Since the method for manufacturing a circumferential ring for constructing a cylindrical storage tank according to the present invention is as described above, the rapid continuity of the steel strip coil is effectively utilized to produce a circumferential ring having only one longitudinal weld line. It can be manufactured efficiently with high roundness and workability. Moreover, by stacking an appropriate number of circumferential rings obtained by this method one above the other and horizontally welding the joints, the circumferential body of a cylindrical storage tank can be easily manufactured.
By reducing the number of welding points, reliability is improved and construction period is shortened.

[Brief explanation of the drawing]

Figures 1, 2, and 3 are explanatory diagrams showing the basic idea of the present invention, Figure 4 is a schematic plan view of manufacturing equipment suitable for realizing the method of the present invention, and Figure 5
The figure is an enlarged view of the roll bender section of the same equipment. 1... Steel band coil, 1a... Formed curved steel plate, A...
Unwinding end, 2...Rotating reel, 3...Roll bender, 4...Horizontal welding beveling machine, 5...Cutting beveling machine, 6...Moment damping transmission device, 7...Advancing direction of curved steel plate unwinding end Changing device, 7a...movable roller, 7b...fixed roller, 8...horizontal rotating roll,
10...Dummy steel plate cutting machine.

Claims (1)

[Claims] 1 Unwind the steel strip wound into a coil,
A vertical bending machine is used to form a curved steel plate with a predetermined curvature, and when the tip of the formed curved steel plate has made approximately one turn around a circle of predetermined curvature and has advanced near the entrance side of the bending machine, the tip of the steel plate is Applying an external force within the elastic limit to the curved steel plate so that the curved steel plate comes off to the outside or inside of the bending machine, and changing the direction of movement while suppressing the bending moment from being transmitted to the exit side of the bending machine, When the curved steel plate is formed to a length sufficient to take a predetermined ring circumference, the forming operation is stopped and the bending process is performed so that the length of the curved steel plate becomes equal to the predetermined ring circumference. The steel plate is cut near the exit side of the forming machine, and after this curve-formed steel plate is extracted from the forming device, the cut end and the unrolled end are welded and joined to form a circumferential ring with a predetermined circumference. A method for manufacturing a circumferential ring for constructing a cylindrical storage tank, characterized by sequential manufacturing.