JPH04118898A - Reinforcing rib installation method for thin wall duct - Google Patents

Abstract

PURPOSE:To install each brim shaped reinforcing rib even onto a thin wall duct the both ends of which is formed with flared sections by way of a specified outer circumferential clearance by dividing reach rib by 2 so as to be formed into rib pieces, and thereby holding the duct from both of the upper and lower sides of the duct. CONSTITUTION:Each brim shaped reinforcing rib 2 is installed onto the outer circumference of a thin wall duct 1 which is 0.3mm in thickness at certain intervals. the both ends of the duct 1 are formed with flared sections 10 so that the ducts 1 can thereby be mutually butt welded. The reinforcing rib 2 is composed of two rib pieces 3 and 4 each of which is in a split half shape, where stepped sections 3a and 4a are formed, which are mutually over-lapped when they are combined with each other. The stepped sections 3a and 4a are mutually over-lapped, and they are spot-welded, so that the rib pieces 3 and 4 are thereby mutually fixed. Following which, the rib 2 is then brazed onto the duct 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of attaching reinforcing ribs to a thin-walled duct.

[Prior Art] In recent years, a duct with a wall thickness of 0.3 mm and a substantially elliptical cross section has been considered as a vacuum duct for use in a synchrotron bending electromagnet section of a large synchrotron radiation facility. However, due to its thin wall thickness of 0.3 m+, when its interior is evacuated, it cannot withstand the external pressure and buckles.

Therefore, it is necessary to reinforce such thin-walled ducts in order to ensure their strength against external pressure, and the installation of rib-shaped reinforcing ribs at a constant pitch on the outer circumference of the duct is being considered. .

[Problem to be Solved by the Invention J] By the way, the above-mentioned thin-walled duct is manufactured by molding each unit length into an elliptical shape by hydraulic molding, and
The actual synchrotron bending electromagnet section is formed by interconnecting the ducts. At this time, it would be awkward to weld thin-walled ducts by butting them against each other, so we formed flared parts that rise outward in the radial direction at both ends, and then welded them by butting each other to form a predetermined curvature. Weld.

By the way, since this flaring process is performed simultaneously with the above-mentioned molding, the reinforcing ribs are attached after the duct molding. For ducts that are simply shaped into an oval shape,
By setting the inner circumference of the reinforcing rib to be slightly larger than the outer circumference of the duct, the rib can be fitted from one end of the duct, ensuring a specified clearance between the outer circumference of the duct and the inner circumference of the rib. Then, good brazing can do the job. However, as mentioned above, in the case of a thin-walled duct with flared portions formed at both ends, the reinforcing ribs cannot be fitted due to the flared portions, and even if the reinforcing ribs can be fitted, The above-mentioned clearance cannot be maintained at a predetermined level, and in any case, satisfactory brazing cannot be performed.

The present invention has been made in consideration of the above circumstances, and its purpose is to install a rib-shaped reinforcing rib on the outer periphery of a thin-walled duct with flare processing applied to both ends through a predetermined clearance. An object of the present invention is to provide a method for attaching reinforcing ribs to a thin-walled duct.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides rib-shaped reinforcing ribs at predetermined intervals on the outer periphery of a thin-walled duct whose both ends are flared for connection. In this method, the reinforcing rib is divided into two to form rib pieces, a thin-walled duct is sandwiched between the rib pieces from above and below, and a predetermined distance is formed between the outer circumference of the thin-walled duct and the inner circumference of each rib piece. After supporting both rib pieces with a jig to maintain the clearance,
The rib pieces are joined together by spot welding, and then both rib pieces are brazed to the thin-walled duct.

[Function] The brim-shaped reinforcing ribs are divided in advance to form rib pieces, and by sandwiching the thin-walled duct with these rib pieces, it can be used even for thin-walled ducts with flared processing on both ends. Reinforcing ribs can be provided on the outer circumference of the duct. Furthermore, with the duct sandwiched between the rib pieces, both rib pieces are supported by a jig and the rib pieces are spot welded together, thereby reducing the clearance between the thin-walled duct and each rib piece. Can be set uniformly.

[Example] An example of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a state in which rib-shaped reinforcing ribs 2 are attached at intervals on the outer periphery of a thin-walled duct 1 having a wall thickness of 0.3 m.

The thin-walled duct 1 is manufactured by hydraulic molding, that is, by molding a previously prepared pipe with a substantially circular cross section into an elliptical shape using internal pressure. As shown in FIG. 2, flared portions 1a are formed at both ends of the thin-walled duct 1 so that the ducts 1 can be butted against each other and welded. The flared portion 1a is formed by bulging both ends of the duct 1 radially outward at the same time as the above-mentioned molding, and then cutting the end face vertically with a laser (flaring processing).On the other hand, the reinforcing ribs 2 are formed by: As shown in FIG. 3, one rib piece 3.4, which is made up of two rib pieces 3.4 that are divided into two parts, has a stepped portion 3a + which overlaps when the rib pieces 3.4 are combined with each other.
4 a is formed.

To attach the reinforcing rib 2 to the thin-walled duct 1, first prepare the thin-walled duct 1 and the rib piece 3.4 having the above-described configuration, and then as shown in FIG. These are combined to create a state in which the thin-walled duct 1 is sandwiched between the top and bottom.

At this time, the rib pieces 3.4 are easily combined by overlapping the stepped portions 3a, 4a of the rib pieces 3.4.

Next, in this state, the rib piece 3.4 is supported by a jig 5 (FIG. 5). As shown in FIG. 6, this jig 5 has a jig body 6 with a U-shaped cross section. , there is an eraser 7 on the inner surface of the main body 6.
It has a structure that forms a Specifically, as shown in FIG. 7, a main body portion 10a has opposing pieces 9a, 9a vertically protruding from a base portion 8a, and a base portion 8b and opposing pieces 9.
b.

9b and a main body part 10b having a groove 7 formed on one side along the direction in which the opposing piece 9b extends, and is constructed by overlapping these main body parts 10a and 10b and tightening them with screws. Here, the facing piece 9a,
9a (or 9b.

9b) is the first (second) outer diameter of the duct 1.
(see figure), and the width L2 of the groove 7 is
Width and outer circumference spacing J2 when rib pieces 3 and 4 are combined
(See Figure 4). Therefore, in this embodiment, the jig 5 is moved in the direction shown by the arrow in FIG. .

After that, the stepped portion 3a of the rib pieces 3 and 4 that overlap each other
, 4a (point A in Fig. 5) is spot welded to fix the rib pieces 3.4 to each other, and then the jig 5 is removed. As a result, the rib pieces 3.4 are integrated and a rib-shaped reinforcement is formed. rib 2
is fitted onto the outer periphery of the thin-walled duct 1 while maintaining a predetermined clearance.

After a predetermined number of reinforcing ribs 2 are fitted onto the outer periphery of the thin-walled duct 1 at predetermined intervals, these ribs 2 are then brazed to the duct 1. This brazing is performed by supporting each rib 2 on a brazing jig, and
A brazing material is placed between the ribs 2 and the duct 1, and then the brazing material is melted in a vacuum furnace to fix the joint between the ribs 2 and the duct 1. Thus, as shown in FIG.
The state with the attached is obtained.

In this way, the rib pieces 3.4 were made by dividing the brim-shaped reinforcing rib 2 in advance, and the thin-walled duct 1 was installed by sandwiching the rib pieces 3.4, so that flared parts were formed at both ends. The brim-shaped reinforcing rib 2 can be reliably attached even to the thin-walled duct 1 having the duct 1a. In addition, since the rib pieces 3.4 were supported by the jig 5 while the thin-walled duct 1 was sandwiched between the rib pieces 3.4, the clearance between the thin-walled duct 1 and each rib piece 3, 4 was reduced. Furthermore, since the rib pieces 3 and 4 are fixed by spot welding after that, even if the jig 5 is removed, this clearance can be maintained. Also, rib piece 3
．． A jig 5 that supports 4 is of a shape that allows these to be inserted. 117, these rib pieces 3.degree. 4 can be supported in a state where their movement is reliably restrained, and from this point of view as well, the above-mentioned clearance can be ensured with high precision. Moreover, in order to support the rib pieces 3 and 4 on the jig 5, it is only necessary to move the jig 5 in the horizontal direction, so the work is extremely simple.

Although the thin-walled duct 1 with a substantially elliptical cross-sectional shape was used in the above embodiment, a racetrack-shaped duct may also be used. However, various types can be used.

[Effects of the Invention] In summary, according to the present invention, the following excellent effects are achieved.

(1) Since the thin-walled duct is sandwiched between two rib pieces with a reinforcing rib divided, the brim-shaped reinforcing ribs can be attached to thin-walled ducts that have been flared at both ends. I can do it.

(2) Also, after sandwiching the thin duct between two rib pieces,
Since both rib pieces were supported by a jig and the rib pieces were spot welded together, the thin-walled duct and the clearance between each rib piece can be set to be minute and uniform. Therefore, the subsequent brazing operation can be performed well, and the external pressure resistance strength of the duct can be reliably improved.

[Brief explanation of the drawing]

FIG. 1 is a partial perspective view showing a thin-walled duct with reinforcing ribs attached by the method of one embodiment of the present invention, FIG. 2 is a diagram showing a thin-walled duct used in the method of one embodiment, and FIG. A diagram showing the reinforcing ribs (rib pieces) used in the method of the embodiment, FIG. 4 shows a state in which a thin-walled duct is sandwiched between rib pieces, and FIG. 5 shows a state in which the rib pieces are supported by a jig. 6 is a schematic perspective view showing an example of the jig, and FIG. 7 is an exploded perspective view of the jig shown in FIG. 6. In the figure, 1 is a thin-walled duct, 1a is a flare portion, 2 is a reinforcing rib, 3 and 4 are rib pieces, and 5 is a jig. Patent applicant: Ishikawajima-Harima Heavy Industries Co., Ltd. Agent Patent attorney: Nobuo Kinutani (1 other person) Figure 1 (a) (b) Figure 2 Figure 3 Figure 4 Figure 5 (b)

Claims (1)

[Claims] 1. In a method of attaching brim-shaped reinforcing ribs at predetermined intervals on the outer periphery of a thin-walled duct whose both ends are flared for connection, the reinforcing ribs are divided into two to form rib pieces; These rib pieces sandwich the thin-walled duct from above and below, and after supporting both rib pieces with a jig so as to maintain a predetermined clearance between the outer circumference of the thin-walled duct and the inner circumference of each rib piece, A method for attaching reinforcing ribs to a thin-walled duct, characterized in that the pieces are joined together by spot welding, and then both rib pieces are brazed to the thin-walled duct.