Inventors: Anton Marincic and Zvonko Milanovic

Field of the Invention

[0001] The present device relates to pipe couplings and in particular relates to a misalignment coupling which is used in the oil and gas industry for connecting piping together having a certain degree of misalignment between the pipes.

Background of the Invention

[0002] There are a number of prior art coupling devices for connecting together the ends of pipes. In the oil and gas industry pipes often carry gases and/or fluids under high pressures and the couplings used to connect pipe ends together must be designed to maintain the coupling integrity under the high pressures present in oil and gas piping systems.

[0003] Unfortunately in new and also in existing installations the pipe ends are not always aligned perfectly and at times it is very difficult to connect misaligned pipe ends together such that the coupling provides the necessary integrity for the connection of the two pipes. As a result there is often a great deal of time and expense in reinstalling misaligned pipes in order to ensure that the connection between the pipe ends has sufficient integrity.

[0004] Therefore there is a need in the industry for a misalignment coupling, which can provide for a connection between misaligned pipes and yet provide the necessary integrity in the connection in order to contain the materials being transported through the piping. Summary of the Invention

[0005] The present concept a misalignment coupling for coupling two pipe sections together, the misalignment coupling characterized in that it includes a seal ring; a right and left hub for attachment of a pipe section to each hub; and wherein right and left flanges for operably urging the hubs together with the seal ring clamped between the hubs, the hubs compressing the seal ring forming a sealing surface thereby placing the coupling in a coupled position.

[0006] Preferably characterized in that the right and left hubs each include a hub conical surface for compressing the seal ring thereby elastically deforming the seal ring and creating a sealing surface between the hub conical surfaces and a seal ring outer diameter when the coupling is in the coupled position.

[0007] Preferably characterized in that the hubs include opposing inner faces defining a gap there between when the coupling is in a coupled position, wherein the hubs are misaligned when the inner diameter of each hub is not parallel to the coupling centerline by an amount of angle alpha and there is a non-uniform gap between the inner faces.

[0008] Preferably characterized in that the opposing inner faces make contact when the coupling is in a coupled maximum misaligned position thereby defining a maximum misalignment position.

[0009] Preferably characterized in that in a coupled aligned position a uniform gap exists between inner faces of the right and left hubs and the hubs do not contact each other. [00010] Preferably characterized in that in the coupled misaligned position a nonuniform gap exists between inner faces of the right and left hubs and the hubs do not contact each other.

[0001 1] Preferably characterized in that each flange includes a flange inner radius for cooperatively mounting onto a matching hub outer radius of each hub when in the coupled aligned position and coupled misaligned position.

[00012] Preferably characterized in that the right and left flanges each include opposed flange inner faces abutting and contacting each other when the coupling is in the coupled position thereby maintaining a preselected gap between inner faces of the hubs.

[00013] Preferably characterized in that the dimensions of the hubs and the flanges are preselected to impart a preselected amount of compression to the seal ring when the flange inner faces make contact with each other.

[00014] Preferably characterized in that the coupling including fasteners for urging the flanges together.

[00015] Preferably characterized in that the coupling including screw fasteners for urging the flanges together.

[00016] Preferably characterized in that the hubs are dimensioned such that the flanges slip over the hubs for assembly of the coupling prior to attachment of the pipe section to each hub.

[00017] Preferably characterized in that each hub including an outer tapered end for welding a pipe thereto. Brief Description of the Drawings

[00018] The misalignment coupling will now be described by way of example only with reference to the following drawings in which;

Figure 1 is a plan view of the misalignment coupling

Figure 2 is a cross sectional view taken along lines AA of Figure 1 of the misalignment coupling showing the coupling in an aligned position.

Figure 3 is a cross sectional view similar to the one shown in Figure 2 however with the coupling shown in a misaligned position.

Description of the Preferred Embodiments

[00019] The present device of a misalignment coupling shown generally as 100 in Figure 2 includes the following major components namely a right hub 102 having an inner face 106, an outer tapered end 1 12, a hub outer radius 110, an inner diameter 114 and a hub conical surface 1 1 1.

[00020] Similarly left hub 104 includes an inner face 108, an outer tapered end 1 12, an inner diameter 114 a hub outer radius 110 and a hub conical surface 111.

[00021] Misalignment coupling 100 further includes a right flange 120 including a flange inner radius 124, a flange inner face 126, and a stud aperture 141. Similarly misalignment coupling 100 includes a left flange 122 including a flange inner radius 124, and a flange inner face 128, and a stud aperture 141.

[00022] Misalignment coupling 100 further includes a seal ring 130 having a seal ring inner surface 136, a seal ring outer diameter 134 which is the seal ring sealing surface 132.

[00023] Misalignment coupling 100 is shown in the aligned position 101 in Figure 2 in which the center line 172 is parallel to the inner diameters 1 14 of each of the right hub 102 and the left hub 104.

In Use

[00024] In use misalignment coupling 100 is butt welded to a pipe, which is butted up against tapered end 1 12 of each of the right hub 102 and left hub 104. The tapered portion of outer tapered end 112 of each of the hubs 102 and 104 forms part of the V groove for a full penetration weld for rigidly connecting a pipe end to the outer tapered end 1 12 of both the right hub 102 and the left hub 104.

[00025] Prior to welding the pipes onto the ends of each of right hub 102 and left hub 104, right flange 120 and left flange 122 is slipped over top of right hub 102 and left hub 104. [00026] Further seal ring 130 is put into the position wherein the seal ring outer diameter 134 makes contact with hub conical surface 111 of both right hub 102 and left hub 104 wherein the contact between the seal ring outer diameter 134 and the hub conical surface 111 forms the seal rings sealing surface 132. Each of the flanges 120 and 122 includes stud apertures 141 for receiving a threaded stud 140 there through and nuts 142 for tightening and for urging together each of the flanges 120 and 122 until flange inner face 126 and flange inner face 128 make contact. This is shown in Figure 2 in the aligned position 101. In aligned position 101 portions of the seal ring 130 has deformed radially inward elastically and the seal ring outer diameter 134 makes positive contact with the hub conical surface 1 1 1 creating a seal ring sealing surface 132 and providing a positive seal between the seal ring outer diameter 134 and the hub conical surface 111 of both the right hub 102 and the left hub 104.

[00027] In the coupled position 129 flange inner faces 126 and 128 make contact and there is a uniform gap 119 between inner faces 106 and 108 of each of the hubs 102 and 104.

[00028] Seal ring 130 is dimensioned such that when the flanges 120 and 122 are urged together with tightening nuts 142 until the inner faces 126 and 128 make contact and seal ring 130 is elastically deformed and makes continuous contact between the seal ring outer diameter 134 and the hub conical surface 111. [00029] Figure 1 shows the use of 8 threaded studs and 8 sets of nuts 142 for tightening together the flanges 120 and 122. Any suitable number of studs could be used depending upon the diameter of the flanges.

[00030] The Right hub 102 and left hub 104 is urged together when right flange 120 and left flange 122 is urged together by contact of the hub outer radius 1 10 with the flange inner radius 124 of the hubs 102 and 104 and the flanges 120 and 122.

[00031] Referring now to Figure 3 the reader will note that the right hub 102 is misaligned by an angle alpha shown as 170 in Figure 3, which is the angle, subtended between the center line 172 and the inner diameter 114 of right hub

102. In a coupled maximum misaligned position shown as 103 in Figure 3 inner face 106 of right hub 102 and the inner face 108 of left hub 104 makes contact at contact point 176 as shown in Figure 3 thereby defining a maximum misalignment position of the coupling. The coupling is in a coupled misaligned position anywhere between the aligned position 101 and the maximum misaligned position

103. The hubs make contact only in the coupled maximum misaligned position 103. Note that even in the misaligned positions the coupling remains coupled meaning that the seal surface does not lose its integrity. Therefore the coupling is described as being in a coupled misaligned position as long as the seal remains intact.

[00032] The misalignment of the joint causes the formation of a non-uniform gap 174 on one side of the joint between inner face 106 and inner face 108 of right hub 102 and left hub 104 respectively.

[00033] The reader will note that there is however at all times maintained a contact and/or seal ring sealing surface 132 between the seal ring outer diameter 134 and the hub conical surfaces 111. Therefore the coupling is always in the coupled position 13 lor 129 meaning a positive seal is in effect even in the misaligned positions.

[00034] When installing misalignment coupling 100 the user will know that the correct amount of compression and/or tightening has taken place when the flange inner faces 126 of right flange 120 makes contact with flange inner face 128 of left flange 122 as shown in Figures 2 and 3. The dimensions of the hubs 102 and 104 and the flanges 120 and 122 are preselected to impart a preselected amount of compression to the seal ring 130 when the flange inner faces 106 and 108 make contact with each other.

[00035] The reader will note that preferably a misalignment of up to 5 degrees shown as alpha 170 can be tolerated by misalignment coupling 100 without affecting the integrity of the joint. It may be possible to have a misalignment of up to 10 degrees however in practice not more than 5 degrees is permitted to maintain a predetermined safety factor.

[00036] It should be apparent to persons skilled in the art of various modification and adaptations of the structure described above are possible without departure from the spirit of the invention the scope of which is defined in the appended claims.