IE55927B1

IE55927B1 - Method for fabricating pipe elbows

Info

Publication number: IE55927B1
Application number: IE277984A
Authority: IE
Original assignee: Foster Wheeler Energy Corp
Priority date: 1983-10-31
Filing date: 1984-10-30
Publication date: 1991-02-27
Also published as: GB8427431D0; GB2149040B; GB2149040A; ES8604432A1; IE842779L; JPS60111720A; ES537019A0

Abstract

In a method for fabricating a pipe elbow a plurality of elbow segment patterns are formed on a plate (see Fig. 1), after which the plate is rolled into a cylindrical shape and, the elbow segments 12a, 14a, 14b are cut out according to the pattern. The segments are then reoriented and joined together to form an elbow.

Description

This invention relates to a method of fabricating a pipe elbow and, more particularly, to such a method in which a plurality of elbow segments are formed and joined together.

In the manufacture of pipes, it is traditionally the practice to form a plurality of pipe segments and then join them by automatic welding work positioners, or the like, at their joints. However, in the fabrication of pipe elbows, each section in the elbow is either structurally dissimilar or oriented in a dissimilar manner, requiring separate manufacturing processes for each segment. This, of course, adds to the cost and labor involved in the fabrication.

It is therefore an object of the present invention to provide a method for fabricating a pipe elbow in which several elbow segments are formed from the same plate, notwithstanding the fact that they are oriented in a different direction in the final assembly.

It is a further object of the present invention to provide a method of fabricating a pipe elbow of the above type which reduces material and labor costs in the fabrication method.

Toward the fulfilment of these and other objects, there is provided herein a method of fabricating an elbow for a pipe from metal plate by forming a plurality of pipe segments each of which contributes a portion of a turn in the run of the pipe provided by the elbow, each segment comprising a linear cylinder and having at least one end whose circumferential edge lies wholly in a plane which intersects the axis of the segment at an angle less than a right angle, of these segments one or a plurality of equal axial lengthed segments have ends whose circumferential edges lie in planes which intersect the axis of the segment with relatively equal and opposite angles, said method comprising marking into segments a flat metal plate which is to be formed by rolling into a cylinder having abutting, corresponding edges, each one of said markings defining said circumferential edges of each of two adjacent segments of the elbow, rolling the plate into said cylinder, dividing the cylinder into said segments along the marked lines, re-orienting the segments to define the elbow and joining the adjacent segments at the said mutually adjacent circumferential edges.

The above brief description of the invention, as well as further objects, features and advantages thereof, will be more fully appreciated by reference to the following detailed description of the presently preferred but nonetheless illustrative embodiment in accordance with the present invention when taken in conjunction with th·-' accompanying drawings in which: Figure 1 is a plan view of a steel plate having a plurality of segment patterns stitch burned thereon; Figure 2 is the plate of Figure 1 rolled into a substantially cylindrical shape; Figure 3 is a view similar to Figure 1 but showing three elbow segments cut out of the aforementioned stitch pattern; Figure 4 is a cross-sectional view showing the segments of Figure 3 welded together and extending over a pipe liner.

Referring to Figure 1 of the drawings, the reference numeral 10 refers in general to a rectangular plate of steel or other similar material having two end portions 10a and 10b and two side portions 10c and lOd. A segment pattern is stitch-burned or otherwise formed in the steel plate as shown and consists of a pair of half segments 12a and 12b formed at the respective ends of the plate, and a plurality of full segments 14a, 14b, 14c, 14d, 14e and 14f formed between the side segments 12a and 12b.

After the pattern has been stitch burned on the plate 10, the latter is rolled into a substantially cylindrical shape as shown in general in Figure 2, with the side edge portions 10c and lOd abutting. The side edge portions 10c and lOd are then joined by welding along their abutting surfaces to form a cylindrical structure as shown in Figure 3. Each of the segments 12a, 12b and 14a-l4f are thus formed into a loop or ring and are removed from the cylindrical structure by finish burning, or the like, as shown in connection with segments 12a, 14a and 14b. Every other segment in sequence from one end is then rotated 180° bo form the desired radius, which, in the example shown, would include segments 12a and 14b.

The segment 12a is then joined at one end portion to a corresponding end portion of the segment 14a and the latter segment is joined at its other end portion to one end portion of the segment 14b as shown in Figure 4. The other end portion of the segment 14b is joined to a straight pipe section 16 forming the end portion of a complete pipe assembly (not shown in its entirety).

It is understood that the aforementioned joining may be by any conventional welding technique.

The segments 12a, 14a, 14b and 16, as assembled in the above manner together form an elbow extending at approximately a forty five degree angle. The elbow thus formed is placed over a wear resistant liner 18 with a filler material 20 disposed between the liner and the elbow to complete the final assembly.

Of course, the other segments 14c, 14d, 14e, 14f and 12b can be utilized in a similar manner to form other elbows of a same or different configuration than the elbow shown in Figure 4. Also, one or more additional segments can be added to the assembly shown in Figure 4 to extend the angular span of the elbow thus formed.

It is thus seen that the method of the present invention permits a very efficient utilization of the material forming the plate 10, yet is efficient also from a labor standpoint.

Other modifications, changes, and substitutions are intended in the foregoing disclosure and in some instances some features of the invention will be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the spirit and scope of the invention herein.

Claims

1. A method of fabricating an elbow for a pipe from metal plate by forming a plurality of pipe segments each of which contributes a portion of a turn in the run of the pipe provided by the elbow, 5 each segment comprising a linear cylinder and having at least one end whose circumferential edge lies wholly in a plane which intersects the axis of the segment at an angle less than a right angle, of these segments one or a plurality of equal axial lengthed segments have ends whose circumferential edges lie in planes which 10 intersect the axis of the segment with relatively equal and opposite angles, said method comprising marking into segments a flat metal plate which is to be formed by rolling into a cylinder having abutting, corresponding edges, each one of said markings defining said circumferential edges of each of two adjacent seg15 ments of the elbow, rolling the plate into said cylinder, dividing the cylinder into said segments along the marked lines, re-orienting the segments to define the elbow and joining the adjacent segments at the said mutually adjacent circumferential edges.

2. A method according to Claim 1 wherein, after said step of 20 rolling and before said step of dividing, the abutting corresponding edges of said plate are joined to form the cylinder.

3. A method according to Claim 1 or Claim 2 wherein said step of re-orienting comprises rotating every other one of said segments in a sequence through 180°. 25

4. A method according to any preceding claim wherein the or each segment marked on the plate between the segments marked at each end thereof are twice the axial length of the said end segments.

5. A method according to any preceding claim wherein said plate is steel and therein said step of joining is by welding.

6. A method according to Claim 1 of fabricating an elbow for a 5 pipe, substantially as hereinbefore described with reference to the accompanying drawings.

7. An elbow for a pipe whenever fabricated by method claimed in a preceding claim.