Pipe element having shoulder, groove and bead and methods and apparatus for manufacture thereof.

PIPE ELEMENT THAT HAS SCALE, THROAT AND CORD AND METHODS AND APPARATUS FOR THE MANUFACTURE OF THE SAME

CROSS REFERENCE TO RELATED APPLICATIONS

This request is based on and claims the priority of: Provisional North American Application No. 61 / 418,967, filed on December 2, 2011, and of: Provisional North American Application No. 61 / 530,771, filed on September 2, 2011 , where both provisional applications are incorporated by reference in their entirety.

FIELD OF THE INVENTION

This invention relates to pipe elements joined by mechanical couplings and methods and apparatus for manufacturing such pipe elements.

BACKGROUND

Different challenges are encountered when designing the pipe elements that have to be joined by mechanical pipe couplings. Such couplings comprise two or more coupling segments joined in end-to-end relationship by threaded fasteners. The segments surround a central space that receives the pipe elements. Each segment has a pair of arcuate projections known as "keys" that are applied to the outer surfaces of the pipe elements. The keys are often received in circumferential throats in the pipe elements that provide a positive mechanical application against the flexural and axial loads applied to the joint or joint. Each segment also defines a channel between its pair of arcuate projections that receives a ring-shaped gasket or gasket. The joint is typically compressed between the segments and the elements of the pipe to effect a fluid tight connection.

The circumferential throats are advantageously formed by work or cold deformation of the side wall of the pipe element because, unlike the cut throats, the material is not removed from the side wall of the pipe and thus to pipe elements of Thinner walls can be made throats through the cold work process. It is advantageous to use thinner wall pipe elements for weight and cost savings in high pressure and / or high load applications. However, the working methods or cold deformation of the prior art and the pipe designs do not produce coupling characteristics and application to the pipe element suitable for sustainable high loads and pressures by comparable cut throat systems used in pipe elements. thicker wall. There are clear advantages that can be obtained through refinements or improvements in the design and manufacture of cold-grounded wall pipe elements with throats that will allow pipe elements with thin-walled throats to be joined by mechanical couplings and used in high pressure / high load applications.

BRIEF DESCRIPTION OF THE INVENTION

The invention relates to a pipe element having an outside diameter and at least one end. In one example, the pipe element comprises a step or shoulder positioned at the end. The step extends circumferentially around the pipe element and has an outward facing surface. The outside facing surface has an outer diameter greater than the outer diameter of the pipe element excluding the step. A throat is positioned next to the step. The throat extends circumferentially around the pipe element. The throat is defined by a first lateral surface positioned adjacent to the step, a second lateral surface positioned separated from the first lateral surface, and a floor surface extending between the first and second lateral surfaces. The soil surface has an outside diameter smaller than the outside diameter of the pipe element excluding the throat.

In another embodiment, the pipe element further comprises a cord positioned adjacent to the throat. The cord extends circumferentially around and protrudes radially outward from the pipe element. The bead has a vertex with an outside diameter greater than the outside diameter of the pipe element excluding the bead.

The invention also includes a pipe element having an outside diameter and a first and second ends. In this exemplary embodiment the pipe element comprises a first and second steps respectively positioned in the first and second extremities. Each of the first and second steps extends circumferentially around the pipe element and has an outwardly facing surface. Each of the surfaces facing outward has an outer diameter greater than the outer diameter of the pipe element excluding the first and second steps. In this embodiment, the first and second throats are positioned adjacent, respectively, to the first and second steps. Each of the first and second throats extends circumferentially around the pipe element. Each of the first and second throats is defined, respectively, by a first lateral surface positioned adjacent to one of the first and second steps, a second lateral surface positioned separated from the first lateral surface, and a floor surface extending between the First and second lateral surfaces. The floor surface of each of the first and second throats has a respective outer diameter smaller than the outer diameter of the pipe element excluding the throats.

This embodiment may further comprise a first and second adjacent positioned cords, respectively, with the first and second throats. Each of the first and second cords extends circumferentially around and protrudes radially outward from the pipe element. Each of the first and second cords has a respective vertex with an outer diameter greater than the outer diameter of the pipe element excluding the first and second cords.

The invention further encompasses the combination of a coupling and at least one pipe element. The pipe element has an outside diameter and at least one end. The coupling comprises a plurality of segments joined together end to end that surround a central space to receive the end of the pipe element. Each of the segments has an arcuate surface to be applied to the pipe element received within the central space. In this exemplary embodiment, the pipe element comprises a step positioned at the end. The step extends circumferentially around the pipe element and has an outward facing surface. The outside facing surface has an outer diameter greater than the outer diameter of the pipe element excluding the step. A throat is positioned next to the step. The throat extends circumferentially around the pipe element. The throat is defined by a first lateral surface positioned adjacent to the step, a second lateral surface positioned separated from the first lateral surface, and a floor surface extending between the first and second lateral surfaces, the floor surface λ having a outer diameter smaller than the outer diameter of the element of '' - - ♦ * · pipe excluding the throat. The arcuate surfaces of the segments are received inside the throat.

In this embodiment, the pipe element may further comprise a cord positioned adjacent to the throat. The cord extends circumferentially around and protrudes radially outward from the pipe element. The bead has a vertex with an outside diameter greater than the outside diameter of the pipe element excluding the bead.

In another aspect, the invention includes a first and second rollers for shaping a side wall of a pipe element. In this aspect, an example of the first roller comprises a first segment having a first outer diameter and a second segment positioned adjacent to the first segment. The second segment has a second outer diameter smaller than the first outer diameter. A third segment is positioned adjacent to the second segment and has a third outer diameter larger than the second outer diameter. An eighth segment is positioned adjacent to the third segment and has an eighth outer diameter smaller than the second outer diameter. A ninth segment is positioned adjacent to the eighth segment and has an eighth outer diameter approximately equal to the second outer diameter.

In this aspect of the invention a second exemplary roller comprises a fourth segment that has a fourth outer diameter and a fifth segment positioned adjacent to said fourth segment and that has a fifth outer diameter larger than the fourth outer diameter. A sixth segment is positioned adjacent to said fifth segment and has a sixth outer diameter smaller than the fifth outer diameter. A seventh segment is positioned adjacent to said sixth segment and has a seventh outer diameter approximately equal to the fifth outer diameter.

In a particular embodiment, the fifth segment comprises a first annular surface positioned next to the fourth segment and oriented substantially perpendicularly to the second axis, and a second annular surface positioned next to the sixth segment and oriented angularly with respect to the second axis.

The invention also includes a device that uses the first and second rollers to cold work an end of a pipe element so that it imparts a shape to a side wall of the pipe element. The device comprises a support frame. The first roller is mounted on the support frame and is rotatable about a first axis. The first roller is adapted to be applied to an inner surface of the pipe element. The means for rotating the first roller around the first axis are also provided. The second roller is mounted on the support frame and is rotatable about a second axis oriented substantially parallel to the first axis. The second roller is mobile to approach and move away from the first roller and is adapted to be applied to an outer surface of the pipe element. Means are also provided for moving the second roller relatively to the first roller to compress the side wall while the rollers rotate. The rollers are arranged relative to each other on the support frame such that:

the fourth segment is aligned with the first segment;

the fifth segment is aligned with the second segment;

The sixth segment is aligned with the third segment.

The means for spinning may comprise an electric motor or a hydraulic motor driven by a pump, and the means for moving may comprise a hydraulic actuator or an expansion screw by way of example.

The invention further encompasses a method of shaping the side wall of a pipe element having an inner surface and an outer surface using the combination of a first and second roller. In one example, the method comprises:

contacting the inner surface of the pipe element at a first point on the first segment of the first roller;

contacting the outer surface of the pipe element with a third point of the fifth segment of the second roller;

rotate one of the first and second rollers thereby causing the other of the first and second rollers and the pipe element to rotate, the first roller circumferentially traverses the inner surface of the pipe element, and the second roller circumferentially traverses the surface outside of the pipe element;

move one of the first and second rollers towards the other of the first and second rollers and deform the side wall of the pipe element through the contact between the inner surface of the pipe element and the first and third segments of the first roller, and make contact between the outer surface of the pipe element and the fifth and seventh segments of the second roller;

continue moving one of the first and second rollers towards the other of the first and second rollers and compress the side wall of the pipe element between the first segment of the first roller and the fourth segment of the second roller;

continue moving one of the first and second rollers towards the other of the first and second rollers and compress the side wall of the pipe element between the second segment of the first roller and the fifth segment of the second roller; and continue moving one of the first and second rollers towards the other of the first and second rollers and compress the side wall of the pipe element between the third segment of the first roller and the fifth and seventh segments of the second roller.

The invention further encompasses a method of repulsing or spinning to form a circumferential step, throat and cord in a pipe element. An exemplary repulsing method comprises:

capture a tip of the pipe element in a mold;

insert a tool or tool into the pipe element;

rotate the tool in an orbit around a longitudinal axis of the pipe element;

increase the diameter of the orbit while the tool is rotated so that it forces the tool against an inner surface of the pipe element;

forming or coupling the pipe element to the mold so that it forms a circumferential step in it, the step having an outer diameter greater than the outside diameter of the rest of the pipe element;

forming the pipe element to the mold so that it forms a circumferential bead in it, the bead having a vertex with an outside diameter greater than the outside diameter of the rest of the pipe element;

force the tool against the inner surface of the pipe element while rotating the tool in the orbit of the increasing diameter by causing a part of the tube between the step and the cord to move radially inwards away from the mold and thereby forming the throat , the throat having an outer diameter smaller than the outer diameter of the rest of the pipe element.

BRIEF DESCRIPTION OF THE DRAWINGS

Figures 1 and 1A are views in longitudinal section of exemplary pipe elements;

Figure 2 is an isometric view of a valve that includes an exemplary pipe element;

Figure 3 is an exploded isometric view of a combination of pipe elements and a pipe coupling;

Figures 3A and 3B are elevational views of the embodiments of the pipe coupling;

Figures 4-6 are longitudinal sectional views of a combination of the pipe elements and a pipe coupling;

Figure 7 is an isometric view of an exemplary roller forming machine for manufacturing pipe elements using a roller forming method;

Figure 8 is an elevation view of an exemplary combination of rollers used to form pipe elements by rollers;

Figures 9-11 are views in longitudinal section illustrating an exemplary method of roller forming pipe elements;

Fig. 12 is a schematic diagram of an exemplary repulping machine for manufacturing pipe elements using a repulping method;

Figure 13 is a schematic end view of the repulping machine shown in Figure 12; and Figures 14-16 are views in longitudinal section illustrating an exemplary method of repulsed pipe elements.

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to pipe elements, combinations of pipe elements and couplings, and methods and devices for working or cold machining pipe elements so that they receive couplings and form a fluid tight junction. Throughout this document the term "pipe element" means any tubular structure, including, for example, the tube 10 as shown in Figure 1, as well as the tubular part 12 of a handling or control component. of fluids such as valve 14 shown in Figure 2. Other components, such as pumps and filters, as well as accessories such as Tes, elbows, bends and reducers are also included as having or comprising "pipe elements" as defined herein.

As shown in Figure 1, the pipe element 10 has an outside diameter 16 that passes through a point on a longitudinal axis 18 at the center of curvature of the pipe element. At least one end 20 of the pipe element 10 is configured to receive a key of a mechanical coupling (not shown), the configuration comprising a step 22 positioned at the end 20, a throat 24 positioned next to the step 22, and a cord 26 positioned adjacent to the throat 24.

As illustrated in detail in Figure 1, the step 22 extends circumferentially around the pipe element and has an outwardly facing surface 28. The surface 28 has an outer diameter 30 that is larger than the outer diameter 16 of the pipe element 10 excluding the step. The step 30 also has a curved surface 32 that faces outwards. The curved surface 32 also extends circumferentially around the pipe element and has a center of curvature on an axis 34 oriented perpendicular to the longitudinal axis 18 of the pipe element 10. In Figure 1, the axis 34 is shown perpendicular to the plane of view and is therefore seen with the front end.

The throat 24 is defined by a first lateral surface 36 that is positioned adjacent to the curved surface 32 of the step 30. The lateral surface 36 may be angularly oriented. The orientation angle 41 may range from about 80 ° to about 85 ° with respect to the longitudinal axis 18. In another embodiment, the lateral surface 36 may be oriented substantially perpendicularly to the longitudinal axis 18. "Substantially perpendicularly" as used herein refers to an angular orientation that may not be exactly perpendicular, but is established as closely as possible in view of manufacturing practices and tolerances. The perpendicular orientation of the first lateral surface 36 stiffens the pipe element radially and helps it maintain its roundness.

A second lateral surface 38 further defines the throat 24.

The second lateral surface 38 is positioned separated from the first lateral surface 36 and is angularly oriented with respect to the longitudinal axis 18. The lateral surface 38 can have an orientation angle 40 from about 40 ° to about 70 °, or about 45 ° at about 65 °. In the particular embodiment shown in Figure 1, the orientation angle 40 is approximately 55 °, which is considered advantageous when the throat receives keys from a mechanical coupling as shown in Figures 3-6.

A floor surface 42 extends between the first side surface 36 and the second side surface 38 of the throat 24. In the exemplary embodiment shown, the floor surface 42 is substantially parallel to the longitudinal axis 18 and has an outer diameter 44 which it is smaller than the outer diameter 16 of the pipe element excluding the throat. The throat 24 also has an inner diameter 17 which, in the embodiment shown in Figure 1, is approximately equal to the inner diameter 19 of the pipe element 10.

The cord 26 is positioned adjacent the second lateral surface 38 of the throat 24 and extends circumferentially also around the pipe element. The bead 26 protrudes outwardly away from the axis 18 and has a vertex 46 with an outside diameter 48 greater than the outside diameter 16 of the pipe element excluding the bead. In the exemplary embodiment shown in Figure 1, the diameter 48 of vertex 46 is smaller than the outer diameter 30 of step 22. The bead 26 increases the radial stiffness of the pipe element and thus helps maintain its roundness.

As shown in Figure 1A, an embodiment 10a of the cordless pipe element is also feasible. Similar to the embodiment 10 shown in Figure 1, for embodiment 10a in Figure 1A the floor surface 42 is substantially parallel to the longitudinal axis 18 and has an outer diameter 44 that is smaller than the outer diameter 16 of the element pipe excluding the throat. The throat 24 also has an inner diameter 17 that is approximately equal to the inner diameter 19 of the pipe member 10a.

For the tube, the configuration of the end of the pipe element 10 (step 22, throat 24 and cord 26) is the same on both ends (not shown for clarity) but other configurations are also feasible in which the extremities may be different. In addition, the pipe elements 50 at opposite ends of the valve 14 also have the aforementioned end configurations that allow the valve, or any other fluid control component or accessory, to be attached to other pipe elements using mechanical couplings, Examples of which are shown in Figures 3, 3A and 3B. Alternatively, valves and other fluid control components and accessories may also have different tip configurations.

In one embodiment, illustrated in Figure 3, the mechanical coupling 52 comprises two or more segments 54 joined together in end-to-end relationship, in this example by threaded fasteners 56. The segments 54 surround a central space 58 that receives the elements of pipe 10 to join them in a fluid tight junction. An elastomer gasket 60 is captured between the segments 54 and has inwardly sealing surfaces 62 that are applied inwardly applied to the surfaces 28 facing outwardly from steps 24 to ensure fluid tightness. Each segment has a pair of arcuate surfaces or keys 64 that protrude inward towards the central space and are received within the throats 24 of the pipe elements 10.

In another embodiment, shown in Figure 3A, the coupling 53 comprises a single segment formed of a unitary body 55 having ends 57 and 59 in separate oriented relationship. The bolt plates 61 extend from the extremities 57 and 59 and a fastener 63 extends between the bolt plates to stretch them and join them when the fastener is tightened. The unitary body surrounds the central space 65 that receives the pipe elements to form a joint. The keys 67 in spaced relationship on each side of the coupling 53 extend circumferentially along the unitary body 55 and project radially inwards. A joint 60 similar to that described above is positioned between the keys. The fastening of the fastener 63 stretches the keys 67 to be applied with throats in the pipe elements and compresses the joint 60 between the unit body 55 and the pipe elements.

Figure 3B shows another embodiment of coupling 69, formed of two segments 71 and 73 joined at one end by a joint 75. Opposite ends 77 and 79 of the segments are in separate facing relationship and connected by a fastener 81. The segments 71 and 73 also have circumferential keys 83 in spaced relationship and a joint 60 is positioned between them. The segments surround a central space 65 that receives the pipe elements to form a joint. The fastening of the fastener 81 stretches the keys 83 to be applied with throats in the pipe elements and compresses the joint 60 between the segments and the pipe elements.

A joint can be formed between two pipe elements 10 by first disassembling the coupling 52 (see Figure 3) and sliding the gasket 60 over one end of one of the pipe elements. The end of the other pipe element is then aligned in proximity to the tip of the first pipe element, and the joint is positioned so that it bridges the small gap or gap between the two extremities of the pipe element, with surfaces 62 of hermetic seal of the joint, respectively applying to the outer surfaces 28 of the steps 24 of each pipe element. Next, the coupling segments 54 are positioned surrounding the joint 60 and the ends of the pipe elements with the keys 64 aligned with respective throats 24 in each pipe element. The fasteners 56 are then applied and tightened so that they stretch from the segments towards each other, apply the keys 64 inside the respective throats 24 and compress the joint 60 against the pipe elements so that they form a fluid tight junction. .

In an alternative embodiment, Figures 4-6 show in detail the application of the pipe elements 10 with a coupling 52 of type ready for installation in which the segments 54 are pre-assembled and maintained in spaced apart relationship by fasteners 56 , the segments being supported on the joint 60. The segments are sufficiently separated so that the pipe elements 10 can be inserted into the central space 58 without disassembling the coupling as shown in Figures 4 and 5. Note that the surfaces 28 facing outwardly from the steps 22 are they apply to the sealing surfaces 62 of the joint 60 and the keys 64 align with the throats 24 in each of the pipe elements. As shown in Figure 6, the fasteners 56 (see also Figure 1) that join the segments 54 to each other are tightened, stretching the segments towards each other. This compresses the joint 60 against the pipe elements to effect a tight seal and forces the keys 64 to the throats 24 to make a positive mechanical connection between the coupling and the pipe elements 10 to effect the joint. In one embodiment, shown in detail in Figure 6, the keys 64 have a cross-sectional shape that is compatible with the throats, and the keys are sized such that a first side key surface 66 is applied to the first surface lateral 36 of the throat, and a second lateral key surface 68 is applied to the second angularly oriented lateral surface 38 of the throat. It is advantageous that surfaces 68 and 38 have complementary orientation angles to maximize surface to surface contact. Orientation angles have been considered for the lateral key surface 68 measured with respect to the longitudinal axis 18 of the pipe element (see also Figure 1) from about 40 ° to about 70 °, or from about 45 ° to about 65 °, or about 55 °. It is also advantageous that surfaces 66 and 36 have complementary orientation angles. Orientation angles for the lateral key surface 66 measured with respect to the longitudinal axis 18 of the pipe element (see also Figure 1) from about 80 ° to about 85 ° have been considered.

In general for this embodiment there will be a space 70 between the floor surface 42 of the throat and a surface 72 that looks radially from the key 64. This is due to variations in tolerance both in the pipe element and in the coupling. Some space between surfaces 42 and 72 is advantageous to ensure that the keys are applied to the throat with a coining action that provides rigidity to the joint and keeps the tubing elements spaced apart from each other under axial compression and tensile loads. The formation of the joint using the coupling embodiments 53 and 69 shown in Figures 3A and 3B proceeds in a similar manner as described above for the installation ready for installation. Other embodiments are also feasible, for example, in which only the vertical key surface 66 is in contact with the throat of the first side surface 36, or only the angularly oriented key surface 68 is in contact with the second side surface 38 of the throat 24. It is also possible that the coupling segments float on the joint 60, in which none of the key surfaces is in contact with the throat surfaces, at least initially until the joint is subjected to load.

Roller training

Figure 7 shows a device 74 to roll out the ends of a pipe element with rollers and shape its side wall. The device 74 comprises a support frame 76 on which a first inner roller or roller 78 is mounted, and a second outer roller or roller 80. The inner roller 78 is rotatably mounted around an axis 82 and is adapted to be applied and support an inner surface of a pipe element during the cold work process described herein. Means 84 for rotating the inner roller are provided with the device 74. Such means may include, for example an electric motor, or a hydraulic motor driven by a pump. The outer roller 80 is mounted on a yoke 86 and is free to rotate about an axis 88 that is substantially parallel to the axis of rotation 82 of the inner roller 78. The yoke 86 allows the outer roller 80 to approach and move away from the roller interior 78 so that it can be applied to an outer surface of the pipe element during roll forming. Means 90 are provided for moving the outer roller 80 over the yoke 86, and such means may comprise, for example, a hydraulic actuator or an expansion screw.

A combination 92 of rollers, by way of example, with inner and outer rollers 78 and 80 according to the invention is shown in detail in Figure 8. The inner roller 78 is formed of a plurality of segments having different outer diameters that cooperate with different segments comprising the outer roller 80 (which can also be distinguished from each other by their respective outer diameters) to give the desired side wall a desired shape. of the pipe element as described here. The inner roller 78 is comprised of a first segment 94 having an outer diameter 94a, a second segment 96 positioned adjacent to the first segment and having an outer diameter 96a smaller than the outer diameter 94a, a third segment 98 positioned adjacent to the second segment and having an outer diameter 98a greater than the outer diameter 96a, a fourth segment 100 positioned adjacent to the third segment and having an outer diameter 100a smaller than the outer diameter 96a, and a fifth segment 102 positioned adjacent to the fourth segment and having an outer diameter 102a approximately equal to the outer diameter 96a. Similarly, the outer roller 80 is comprised of a first segment 104 that has an outer diameter 104a, a second segment 106 positioned adjacent to the first segment 104 and that has an outer diameter 106a greater than the outer diameter 104a, a third segment 108 positioned adjacent to the second segment 106 and having an outer diameter 108a smaller than the outer diameter 106a, and a fourth segment 110 positioned adjacent to the third segment 108 and having an outer diameter 110a approximately equal to the outer diameter 106a.

When the combination of rollers shown in Figure 8 is mounted on the device 74 for cold working the side wall of a pipe element, the rollers are aligned so that they cooperate with each other and impart the desired shape to the side wall. In the example shown in Figures 8-11, the segment 94 in the inner roller 78 is aligned with the segment 104 in the outer roller 80; segment 96 in the inner roller is aligned with segment 106 in the outer roller; segment 98 in the inner roller is aligned with segment 108 in the outer roller, and segments 100 and 102 in the inner roller are aligned with segment 110 in the outer roller.

The annular surfaces in each of the rollers, formed when there are adjacent segments in the same roller that have different outside diameters, also cooperate in pairs with each other to impart the desired shape to the side wall of the pipe element. As also shown in Figure 8, an annular surface 112 positioned on the inner roller 78 between the segments 94 and 96 cooperates with an annular surface 114 positioned on the outer roller 80 between the segments 104 and 106 to form the first lateral surface 36 of the throat 24. The annular surface 114 may be considered part of segment 106 and, in this example, is oriented substantially perpendicularly with the axis of rotation 88 of the outer roller 80. Additionally, an annular surface 116 positioned on the outer roller 80 between the segments 106 and 108 cooperates with an annular surface 118 positioned on the inner roller 78 between segments 96 and 98 to form the second lateral surface 38 of the throat 24. The annular surface 116 may also be considered part of segment 106, and is angularly oriented with respect to axis 88. Orientation angles 120 may range from about 40 ° to about 70 °, or from about 45 ° to about 65 °, or They can be approximately 55 °. In the example shown, the annular surfaces on the inner roller 78 will have substantially the same orientation as the annular surface on the outer roller 80 with which they cooperate, however, other configurations are of course feasible. The proper alignment between rollers 78 and 80 and their respective annular segments and surfaces is established and maintained by a flange 122, which, in this example, extends radially outward from the inner roller 78 and is applied to a throat 124 in the outer roller 80 when the outer roller 80 is moved towards the inner roller 78 to compress the pipe element between them during cold work.

Figures 9-11 illustrate an exemplary method for roll forming a pipe element 10 to impart the shape of the side wall as shown in Figure 1. As shown in Figure 9, the element of Pipe 10 is supported on the inner roller 78 with its inner surface 126 which contacts at least two of the segments 94, and 102 at respective contact points 128, 129 and 130. For relatively short pipe elements, the contact can be in 128, 129 and 130 or in any two of the three. For longer pipe elements, the contact will be at 128 and can be at 129 and 130. The outer roller 80 is moved towards the inner roller 78 and contacts the outer surface 132 of the pipe element 10 with the segment 106. The flange 122 on the inner roller 78 acts as a stop to properly position the pipe element axially on the rollers. Once both the inner and outer roller 78 and 80 are in contact with the pipe element 10 the inner roller is rotated around the axis 82 by the rotation means 84. This causes the pipe element 10 to rotate in the same direction as the inner roller 78, and the outer roller 80 rotates in the opposite direction around its axis 88. Although it is advantageous to rotate the inner roller and move the outer roller towards it, It is understood that other combinations of rotation and movement of the rollers are also feasible. It is also practical to keep the stationary and stationary pipe element and move the machine around the longitudinal axis of the pipe element while compressing the side wall of the pipe element between the two rollers. In this case both rollers can rotate in a vacuum, that is they are not driven in rotation, but they rotate as a result of friction between the rollers and the pipe element.

As shown in Figure 10, the outer roller 80 is moved towards the inner roller 78 to compress the pipe element between the rollers while the rollers are rotating. The side wall 134 of the pipe element is thereby deformed through the contact between the inner surface 126 of the pipe element and the segments 94 and 98 of the inner roller 78, and the segments 106 and 110 of the outer roller 80. This action begins to form the step 22, the throat 24 and the cord 26 on the side wall 134. The rollers and the pipe element continue to rotate, and, as shown in Figure 11, the outer roller 80 is further moved. towards the inner roller 78 to further compress the side wall 134. The side wall 134 is compressed between the segments 94 and 104 to form the step 22, the compression force between the segments decreasing the side wall over the region of the step 22 and enlarging its diameter to a desired outer end diameter 30 as shown in Figure 1. The side wall 134 is also compressed between segments 96 and 106 to establish the final dimensions of the throat floor 42, including its outer diameter 44 shown in Figure 1. In certain embodiments, the side wall 134 is also compressed between segments 96 and 106 to establish that the inner diameter 17 of the part of the pipe element 10 comprising the throat 24 is approximately equal to the inner diameter of the pipe 19 (which does not it is compressed between the rollers) as shown in figure 1. As further shown with respect to Figure 11, the side wall 134 is compressed between the annular surface 116 and the annular surface 118 to form the second lateral surface 38 of the throat 24 (the first lateral surface having been formed by cooperation between annular surfaces 112 and 114). The segment 110 also contacts the outer surface 132 of the pipe element 10 to aid in the formation of the cord 26.

Spinning Training

It is advantageous to form the circumferential step, throat and cord using repulsive or spinning techniques. The repulsed uses a fixed outer mold and a roller tool that rotates in an orbit inside the mold. The pipe element is held within the mold between it and the tool, and the tool orbits around the longitudinal axis of the pipe. The orbit of the tool is increased in diameter and the tool is forced against the inner surface of the pipe element. When the tool rotates, it forces the end of the pipe element to adapt it to the shape of the tool and the mold.

The repulsed is advantageous because it eliminates the sensitivity of the process to the variation of tolerance of the outer diameter of the pipe element. Although techniques such as roll profiling can be used to cold work the pipe element and produce the desired step-cord-throat shape, it is difficult to establish the outer diameters of the step and throat with an acceptable degree of repeatability due to the variation in the outer diameter of the pipe element. However, using the repulsed with its fixed outer mold, the dimensional variations of the outer diameter of the pipe element are not relevant since the reliability of the outer mold establishes the dimensions of the outer surface of the pipe element regardless of the initial diameter of the pipe element. pipeline.

Figures 12 and 13 schematically represent an exemplary spin or roll forming machine 136. As shown in Figure 13, the machine 136 includes a mold 138 formed in four sections 140, 142, 144 and 146. The mold sections are mounted on bearings (not shown) and are slidably movable by approaching and moving away between yes using respective actuators 148, 150, 152 and 154. In this example there are four mold sections configured in offset pairs (140 and 142,144 and 146) but molds having only two sections are also feasible. As shown in Figure 12, a repulping tool 156 is mounted in a housing 158. The housing 158 has a fixed axis of rotation 160 and is mounted on a carriage 162 that moves along guide rods 164 approaching and moving away from the mold 138. An actuator 166 effects the movement of the carriage 162 and therefore the movement of the repulping tool 156 approaching and moving away from the mold. The housing 158 is rotated about the axis 160 relative to the carriage 162 on bearings 168 by an electric motor 170 also mounted on the carriage. The rotation axis 160 of the housing 158 is substantially parallel to the longitudinal axis 161 of the defined opening when the mold sections 140, 142, 144 and 146 are carried together. However, the repulping tool 156 may be moved relative to the housing 158 in one direction so that it displaces its longitudinal axis 172 of the rotation axis 160 of the housing. The displacement movement of the repulping tool 156 is by means of an actuator 174 mounted on the housing 158. A spring 176 provides the recovery force that moves the longitudinal axis 172 of the repulsed tool back to coaxial alignment with the axis of rotation. 160 of the housing when the force of the actuator 174 is relieved.

As shown in Figure 14, the mold sections (140 being shown) have an inner surface 178 shaped to produce a desired final shape of the outer surface 134a of the pipe element 134 during the repulping or spinning. In addition, the repulping tool 156 has an outer surface 180 formed to cooperate with the inner surfaces 178 of the mold sections and allow the material of the pipe element 134 to deform and flow so that when, during the repulping process, the outer surface 180 of the repulping tool 156 is forced against the inner surface 134b of the pipe element 134, the outer surface 134a of the pipe element 134 takes the desired shape defined by the inner surfaces 178 of the mold 138.

In operation, as illustrated in Figures 13-16, actuators 148 and 150 move respective mold sections 140 and 142 away from each other. Similarly, the actuators 152 and 154 move the respective mold sections 144 and 146 away from each other, thereby opening the mold 138. The pipe element 134 can then be inserted into the mold. As shown in Figure 14, the mold 138 is then closed leading the respective mold sections 140 and 142, 144 and 146 to be joined using their respective actuators to capture the end of the pipe element 134. Next, as shown in figures 12 and 14, the actuator 166 moves the carriage 162 towards the mold 138. The repulping tool 156 with its longitudinal axis 172 positioned at this time in coaxial alignment with the rotation axis 160 of the housing 158, and therefore also in coaxial alignment with both the longitudinal axis 161 defined by the mold 138 and the longitudinal axis 182 of the pipe element 134, is moved towards the mold 138. The repulping tool 156 is inserted into the pipe element 134 captured by the mold. The housing 158 is then rotated by the motor 170 about its axis of rotation 160, and the actuator 174 moves the longitudinal axis 172 of the repulping tool 156 out of coaxial alignment with the longitudinal axis 160 of the housing. This configuration is shown in Figure 15, where the axis 172 of the repulping tool 156 is also displaced from the longitudinal axis 182 of the pipe element 134. This eccentric configuration causes the repulping tool 156 to rotate about the longitudinal axis 182 of the pipe element 134 in a circular orbit upon rotation of the housing 158. The diameter of the orbit increases when the actuator 174 continues to move the repulping tool 156 further off the axis of rotation 160 of the housing 158. Continued movement of the repulping tool 156 relative to the housing 158 while the housing is rotating forces the tool against the inner surface 134b of the pipe element 134. As shown in Figure 16, the repulping tool 156 travels around the inner surface of the pipe element in its orbit and cold works the material, forcing the outer surface 134a of the pipe element 134 to adapt substantially in the form of the inner surfaces 178 of the mold 138. In this example, the step 22, the throat 24 and the cord 26 are formed. However, it is also possible to form only one step and the throat, or only the cord and throat, depending on the shape of the mold and the repulsed tool. Note that in order to mitigate the friction between the repulping tool 156 and the inner surface 134b of the pipe element 134, the repulping tool is free to rotate about its longitudinal axis 172. Once the desired step-throat-throat form is reached at the end of the repulsing process, the rotation of the housing 158 is stopped, the longitudinal axis 172 of the repulping tool 156 is moved back to alignment with the longitudinal axis 160 of the housing, and carriage 162 moves away from mold 138, thereby removing the repulping tool 156 from within the pipe element 134. The mold 138 is then opened by separating the mold sections 140, 142,144 and 146, thus allowing the withdrawal of the formed pipe element from the mold.

It is noted that when the repulsed is used to simultaneously form both the step 22 and the cord 26 on opposite sides of the throat 24 as described above, the material of the pipe element is forced to flow to the area of ​​the pipe element that defines the throat such that the throat is formed by the material that moves radially inward towards the longitudinal axis 182 of the pipe element 134 in the direction opposite the increasing diameter of the orbit of the repulping tool 156. The region of the pipe element forming the throat 24 moves away from the interior surfaces 178 of the mold and forms a space 184 between the floor 42 of the throat and the interior surfaces 178 of the mold 138. The floor 42 of the throat is of smaller diameter than mold 138 at the end of the forming process. This movement of the material of the pipe element contrary to the radially outward movement of the repulping tool 156 is unexpected, and allows the pipe elements 134 to be formed in that the outer surface 134a of the throat 24 has a diameter 186 smaller than the diameter 188 of the outer surface of the rest of the pipe element; that is, the outer surface 134a of the pipe element excludes throat 24. It was previously thought that such a configuration was only possible with roller profiling of the pipe element between the two rotating rollers, but the repulping according to the invention allows this configuration to be achieved while maintaining the precise and repeatable exterior dimensions of the pipe element due to the effect of the fixed mold that captures the pipe element. This is unexpected because it was thought that the rotating formation could expand only one pipe element; that is, any part of a pipe element deformed by the repulsed must have a diameter larger than the original dimension. Therefore, according to common wisdom, it would not be possible, in a repulsed process, to start with a pipe element that has a first outer diameter and end with a part of the pipe element that has a second outer diameter smaller than the first diameter outside, but applicants have achieved this by using the repulsed in the method according to their invention.

The configurations of the pipe element comprising the step, the throat and the cord, and the methods and apparatus for creating the configurations as shown and described herein allow thin-walled pipe elements to be joined by mechanical couplings and used in applications. high pressure / high load previously thought to be unsuitable for thin-walled pipe elements and mechanical couplings provided with a throat. Various additional advantages have also been achieved over the prior art pipe elements. For example, it is known that the outer diameter 186 of the throat floor 42 is an important dimensional parameter for the compatibility between couplings and pipe elements in view of the manufacturing tolerances of the diameter of the pipe element. The repulping method described here allows this parameter to be controlled so that throats can be formed that are compatible with the couplings for both the maximum and minimum tolerances of the pipe diameter. In addition, the combination of the enlarged step diameter 190 (step surface 22 facing outwardly larger than the outer diameter of the pipe element) and the reduced throat floor diameter (outer diameter of the floor 42 of the throat smaller than the outer diameter of the pipe element) allows lighter weight couplings to be used without compromising performance. It is also easier to design the couplings due to the tighter tolerances in which the throat and step dimensions can be maintained. Practically, this translates into lower cost couplings in lower and stronger weight joints that resist higher internal pressures. The design of the joint is also simplified due to the tighter tolerances allowed, and it is easier to manage the size of the space that is formed between the coupling segments through which the joint can be extruded and blown under high pressures. Manufacturing advantages are also assured as there is less reduction of the pipe element and less cold work is required which means lower residual stresses, higher remaining elongations, and stronger pipe elements. The addition of the cord 26 allows a more rigid joint and allows the key to fill the throat and employ a coining action to be advantageous. The coining action keeps the pipe elements inside the coupling at a constant distance even when they are under axial compression, due, for example, to thermal loads or a vertical pipe stacking. This prevents the pipe elements from crushing and damaging the leg of the center of the joint if present. The enlarged step also allows the throat to be relatively shallow and has a lower internal profile within the pipe element. A lower profile throat at each joint causes less head loss and less turbulence in the fluid flowing through the pipe elements. Additionally, forming the concentric throat with the step achieves a more uniform application between the coupling and the pipe elements, further decreasing the probability of leakage.