Device and method for cable splicing

Abstract

A joint for a skin-effect heating cable is provided. The joint includes a primary mat, a secondary mat, a connector, and an external cold shrink tubing. The primary mat is configured to shrink onto a portion of an insulation layer of a first portion of the heating cable, the secondary mat is configured to shrink onto a portion of an insulation layer of a second portion of the heating cable, the connector is configured to electrically couple the first portion of the heating cable to the second portion of the heating cable, and the external cold shrink tubing is configured to shrink onto the primary mat, the secondary mat, and the connector.

Description

[0001] Related applications

[0002] This application claims priority to U.S. Provisional Application No. 62 / 978,170, filed February 18, 2020, which is incorporated herein by reference in its entirety. Background Art

[0003] During the construction or maintenance of an electrical system, it may be necessary to connect two cables together. In certain applications, a heat shrink joint utilizing heat shrink tubing can be used to connect the two cables together. More specifically, a heat shrink joint can be used to connect the conductors of two cables together. For example, the heat shrink joint can utilize a soldering method or a mechanical method such as a crimp connection. Once the conductors are connected, exposed wires or mechanical connections may exist between the insulated sections of the two cables. These exposed sections can be covered with heat shrink tubing, which provides a moisture barrier and electrical insulation.

[0004] In some applications, another option for joining cables is a cold shrink joint. A cold shrink joint may include a pre-expanded sleeve that collapses and shrinks around the cable and connector, conforming to their outer surfaces. The generally circular pre-expanded sleeve does not shrink beyond its intended shape. Other options for joining cables may utilize push-on joints using materials including rubber. Still other joints may utilize adhesive tape, such as self-fusing tape. Summary of the Invention

[0005] The present disclosure addresses the need for an easily installable, high-temperature-resistant joint for certain high-voltage cables, such as high-voltage, in-line, skin-effect heating cables. In one aspect, a joint system for a skin-effect heating cable is provided, the skin-effect heating cable having an insulation layer and including a first portion at least partially disposed within a first heating tube and a second portion at least partially disposed within a second heating tube. The joint system includes a joint and a junction box. The joint includes a primary cold shrink pad that shrinks onto a first section of the insulation layer of the first section of the heating cable and a secondary cold shrink pad that shrinks onto a second section of the insulation layer of the second section of the heating cable. The joint also includes a connector electrically coupled to a first conductor of the first section of the heating cable and a second conductor of the second section of the heating cable, and an external cold shrink tubing including an outer semiconductive layer. The external cold shrink tubing shrinks onto the primary pad, the secondary pad, and the connector. A metal junction box is welded to and electrically connected to the first and second heating tubes, the metal junction box housing the joint and electrically connected to the outer semiconductive layer of the external cold shrink tubing.

[0006] In another aspect, a joint for a skin-effect heating cable is provided. The skin-effect heating cable includes an insulation layer and is disposed in a heating tube. The joint includes a primary cold shrink pad, a secondary cold shrink pad, a connector, and an external cold shrink tubing. The primary cold shrink pad is shrunk onto a first segment of the insulation layer of a first portion of the heating cable. The secondary cold shrink pad is shrunk onto a second segment of the insulation layer of a second portion of the heating cable. The connector is electrically coupled to a conductor of the first portion of the heating cable and a conductor of the second portion of the heating cable. The external cold shrink tubing is shrunk onto the primary pad, the secondary pad, and the connector and is in electrical contact with a metal junction box that is electrically connected to the heating tube.

[0007] In yet another aspect, a method for installing a cold shrink joint on a skin-effect heating cable is provided. The method includes removing an outer semiconductive layer along a first portion of the heating cable to expose a first section of the insulation layer of the heating cable, and installing a primary mat over at least a portion of the first section of the insulation layer. The method also includes removing the outer semiconductive layer along a second portion of the heating cable to expose a second section of the insulation layer of the heating cable, and installing a secondary mat over at least a portion of the second section of the insulation layer. The method also includes installing cold shrink tubing over the primary mat and the secondary mat, and placing the cold shrink tubing in electrical contact with a junction box.

[0008] The foregoing and other aspects and advantages of the present invention will become apparent from the following description. In the description, reference is made to the accompanying drawings, which form a part hereof, and in which there is shown by way of illustration a preferred embodiment of the invention. However, such embodiments do not necessarily represent the full scope of the invention, and reference is therefore made to the claims, which are used herein to interpret the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is an isometric view of the heater cable.

[0010] Figure 2 is an isometric view of a heating cable and grease applicator.

[0011] Figure 3 According to some embodiments of the present invention Figure 2 Isometric view of the first portion of the heating cable and the main pad included in the joint.

[0012] Figure 4 According to some embodiments of the present invention Figure 3 Isometric view of a first section of a heating cable and a second section of a heating cable.

[0013] Figure 5 yes Figure 4 The main pad and the secondary pad and the Figure 3 Isometric view of the external cold shrink tubing in the joint.

[0014] Figure 6 is included in Figure 3 A side view of the connector in the mating portion.

[0015] Figure 7 After installation Figure 5 Isometric view of the external cold shrink tubing.

[0016] Figure 8 is an isometric view of a junction box with a top portion removed from a bottom portion according to some embodiments of the present invention.

[0017] Figure 9 yes Figure 8 An isometric view of a junction box with the top portion attached to the bottom portion.

[0018] Figure 10 is a side view of another exemplary joint according to some embodiments of the present invention.

[0019] Figure 11 After installation Figure 10 The external cold shrink tubing and the Figure 10 Longitudinal cross-sectional view of the components in the shrink joint.

[0020] Figure 12 is included in Figure 10 Side view of the main pad in the shrink joint.

[0021] Figure 13 is an isometric view of another junction box according to some embodiments of the present invention with a top portion of the junction box removed from a bottom portion, and Figure 10 The shrink joint is arranged in the bottom part.

[0022] Figure 14 yes Figure 13 An isometric view of a junction box with the top section attached to the bottom section. DETAILED DESCRIPTION

[0023] Before any embodiments of the present invention are explained in detail, it should be understood that the application of the present invention is not limited to the details of construction and arrangement of the parts set forth in the following description or illustrated in the accompanying drawings. The present invention is capable of other embodiments and can be practiced and performed in many other ways. In addition, it should be understood that the words and terms used herein are for descriptive purposes and should not be considered restrictive. The use of "including," "comprising," or "having" and their variations herein is intended to cover the items listed thereafter and their equivalents as well as additional items. Unless otherwise specified or limited, the terms "mounted," "connected," "supported," and "coupled" and their variations are used broadly and cover direct and indirect mounting, connection, support, and coupling. In addition, "connected" and "coupled" are not limited to physical or mechanical connections or couplings.

[0024] The following discussion is presented to enable those skilled in the art to make and use embodiments of the present invention. Various modifications to the illustrated embodiments will be apparent to those skilled in the art, and the general principles herein may be applied to other embodiments and applications without departing from embodiments of the present invention. Therefore, embodiments of the present invention are not intended to be limited to the embodiments illustrated, but rather to be in the widest sense consistent with the principles and features disclosed herein. The following detailed description is read with reference to the accompanying drawings, in which similar elements in different drawings have similar reference numerals. The accompanying drawings depict selected embodiments and are not intended to limit the scope of embodiments of the present invention, and the drawings are not necessarily drawn to scale. Those skilled in the art will recognize that the examples provided herein have many useful alternatives and fall within the scope of embodiments of the present invention.

[0025] Figure 1 An exemplary heater cable 100 is shown according to various embodiments. The heater cable 100 can be a skin effect heating cable that is configured to contact a heat pipe. For example, in a skin effect heating system, heat is generated along a heat pipe that is thermally coupled to a pipe to be heated. The heater cable 100 is mounted inside the heat pipe and connected to the heat pipe at one end. Alternating current (AC) is passed through the heater cable 100 and returned through the heat pipe, thereby generating heat. The heater cable 100 can be a high voltage heating cable, for example, operating at a nominal voltage of five kilovolts, ten kilovolts, or more.

[0026] According to at least one embodiment, the heater cable 100 is Figure 1 Each layer is peeled off in sequence to clearly illustrate its layered structure. Figure 1 As shown, heater cable 100 includes a conductor 102 at its core, an electrical insulation layer 104 , an optional inner semiconducting layer 106 , and an outer semiconducting layer 108 .

[0027] Conductor 102 can be any suitable conductive material, including tinned copper, nickel-plated copper, aluminum, steel, gold, platinum, silver, etc. Conductor 102 can be a solid conductor wire or can be stranded wire. Conductor 102 can be a #4 (i.e., 4 American Wire Gauge or 4 AWG or equivalent) size conductor. In some embodiments, conductor 102 can be smaller than a #4 size conductor. In some embodiments, conductor 102 can be a #2 (i.e., 2 American Wire Gauge or 2 AWG or equivalent) size conductor or smaller.

[0028] Conductor 102 is encapsulated within electrical insulation layer 104. Non-conductive electrical insulation layer 104 may be any suitable material, including silicone, PFA, EPDM rubber, XPLE, etc. Certain materials, such as silicone and PFA, may have better heat resistance than other materials and therefore may be more desirable in applications requiring high temperature resistance.

[0029] In some embodiments, the entire circumference of conductor 102 is in physical contact with electrically insulating layer 104. In other embodiments, such as Figure 1 As shown, the conductor 102 is encapsulated within or in direct electrical contact with the inner semiconducting layer 106. In such an embodiment, the inner semiconducting layer 106 is then encapsulated within the electrically insulating layer 104.

[0030] An outer semiconducting layer 108 surrounds the electrically insulating layer 104. The outer semiconducting layer 108 can be any suitable semiconducting material, combination of semiconducting materials, or semiconducting combination of electrically insulating material(s) and conductive material(s). In some embodiments, the outer semiconducting layer 108 can be the same base material as the insulation (e.g., silicone, PFA, etc.), but can be mixed, doped, or otherwise loaded with carbon black or another conductive material to make the layer 108 semiconducting. More specifically, and as further described herein, the composition of the outer semiconducting layer 108 can be selected so that the outer semiconducting layer 108 contacting the inner surface of the heat pipe being heated reduces or eliminates corona or partial discharge without interfering with the electrical relationship between the heater cable 100 and the heat pipe that achieves skin effect heating. Thus, the resistivity of the material comprising the outer semiconducting layer 108 can be sufficiently low to reduce or eliminate corona at the outer surface of the heater cable 100. In particular, the resistivity can be low enough to prevent corona discharge even at locations along the length of the heater cable 100 where the heater cable 100 is not in continuous contact with a cooperating heat pipe.

[0031] Furthermore, the resistivity of the outer semiconducting layer 108 can be sufficiently high that the return AC current flowing along the inner surface of the heat pipe in the opposite direction to the AC current in the conductor 102 does not substantially flow into the outer semiconducting layer 108. In particular, it should be understood that the heat pipe transport of the return skin effect current can contribute more than half (typically about 70%) of the thermal energy in a skin effect heating system (with the heater cable 100 contributing the remainder); the resistivity of the outer semiconducting layer 108 can, at most, allow only a small portion of the return current to flow into or through the outer semiconducting layer 108, such that the skin effect heating of the heat pipe is not disrupted. For example, the outer semiconducting layer 108 can divert less than about 1% of the return current away from the inner surface of the heat pipe.

[0032] In various embodiments that minimize or eliminate corona discharge and heat loss, the bulk resistivity of the outer semiconducting layer 108 may be between 10 and 20 nm. 1 ohm-cm and 10 6 ohm-cm, or within 10 0 ohm-cm and 10 2 ohm-cm, or between 5 ohm-cm and 50 ohm-cm, inclusive. In addition, in some embodiments, the bulk resistivity may be 10 9 ohm-cm or higher while maintaining a beneficial effect. In some embodiments, the outer semiconductive layer 108 can be applied to the insulating layer 104 by standard extrusion and / or coextrusion processes and can have a minimum thickness of about 0.5 millimeters (mm). In other embodiments, the outer semiconductive layer 108 can be applied by other methods, such as wrapping a length of semiconductive tape around the insulating layer 104 to form the outer semiconductive layer 108. A suitable semiconductive tape can have a minimum thickness of about 0.1 mm. In any application method, the maximum suitable thickness of the outer semiconductive layer 108 may be limited by cost considerations, availability of materials, ease of application, and resistance to damage (e.g., being pulled through a heat pipe during installation). With respect to practical considerations, such as the overall diameter of the heater cable and the relative diameter relative to the inner diameter of the heat pipe in which the heater cable 100 is installed, the upper limit of the thickness of the outer semiconductive layer can be between 5 mm and 10 mm, inclusive.

[0033] Now refer to Figures 2 to 7 Some embodiments provide a joint 210 (e.g., Figures 6 and 7 That is, the joint 210 is operable to electrically and physically connect the first portion 200a of the heating cable 200 to the second portion 200b of the heating cable 200 while still allowing proper skin effect heating operation. The heating cable 200 may include a conductor 202 (e.g., Figure 3 ), an electrically insulating layer 204 and an outer semiconductive layer 208. In some embodiments, the heating cable 200 may be used in conjunction with the heating cable 200 as described above with respect to Figure 1 The described combined heat pipe for skin effect heating is the same as or substantially similar to the heating cable 100. For example, the conductor 202 of the heating cable 200 may be substantially the same as Figure 1 The conductor 102 shown is the same as described above. The electrical insulation layer 204 of the heating cable 200 may be substantially the same as Figure 1 The outer semiconductive layer 208 of the heating cable 200 may be substantially the same as the electrically insulating layer 104 shown and described above. Figure 1 The outer semiconductive layer 108 shown in FIG and described above is the same. The heating cable 200 may also include an optional inner semiconductive layer 206 (e.g. Figure 3As shown), the inner semiconducting layer 206 can be Figure 1 The optional inner semiconducting layer 106 shown and described above is substantially the same.

[0034] In some embodiments, the joint 210 includes at least one cold shrink tubing as further described below, and thus, the joint 210 can be referred to as a cold shrink joint. For example, in some embodiments, the joint 210 can include a grease applicator 212 containing grease 214, a primary pad 216 (e.g., a primary cold shrink pad), a secondary pad 228 (e.g., a secondary cold shrink pad), an outer cold shrink tubing 230, and a connector 234.

[0035] Specific reference Figure 2 , the heating cable 200 may include a first portion 200A. Along the first portion 200A, the outer semiconductive layer 208 may be removed by a qualified technician to expose a length of the electrically insulating layer 204. For example, the outer semiconductive layer 208 may be stripped to a predetermined minimum length (defined by Figure 3 224 in the cut end) so that arcing or surface tracking does not occur from the connection area of ​​the two parts of the cable 200 (as described below) to the outer semiconducting layer 208.

[0036] refer to Figure 2 as well as Figure 3 Grease 214 can be applied to at least a portion of the exposed length of the electrical insulation layer 204 using a grease applicator 212. For example, the grease applicator 212 can be a grease-containing tube or sleeve provided with the joint 210. When the joint 210 is installed, the grease 214 can help eliminate potential air pockets between the primary pad 216 and the electrical insulation layer 204. For example, air pockets can increase the risk of electrical discharge, especially for cables operating at voltages of approximately five kilovolts or higher.

[0037] As noted above, the joint 210 can include a primary gasket 216. In some embodiments, the primary gasket 216 can be a cold shrink tubing, such as a silicone cold shrink tubing, that has been pre-formed into a predetermined shape and then pre-expanded on an inner spiral hold out 218 (also referred to as an inner spiral). The inner spiral 218 can provide sufficient rigidity to hold the primary gasket 216 in an expanded position and can be removed by a qualified technician pulling on the rip cord portion 220, which will gradually unwind the inner spiral 218 from a first end 222 of the inner spiral 218 to a second end of the inner spiral 218 opposite the first end 222. As the qualified technician gradually removes the inner spiral 218, the primary gasket 216 shrinks over the electrical insulation layer 204 and any grease 214.

[0038] The main pad 216 can thus be positioned over at least a portion of the length of the exposed electrically insulating layer 204. More specifically, the main pad 216 can be positioned over a portion of the electrically insulating layer 204 extending from the cut end 224 of the outer semiconductive layer 208 to the exposed end 226 of the main pad 216, such that a small portion of the insulating layer 204 (e.g., a 5 mm length of the insulating layer 204) can extend beyond the exposed end 226 of the main pad 216. In some embodiments, the main pad 216 can be approximately 75 mm long. Additionally, portions of the electrically insulating layer 204 not surrounded by the main pad 216 can be removed to expose the conductor 202.

[0039] More specifically, Figure 4 A first portion 200A of the heating cable 200 and a second portion 200B of the heating cable 200 are shown. The main gasket 216 is shown retracted over the exposed electrically insulating layer 204 of the first portion 200A. The electrically insulating layer 204 and the inner semiconductive layer 206 remaining on the outside of the main gasket 216 can be stripped away to expose the first segment 202A of the conductor 202. In some embodiments, the first segment 202A can be extended enough to be inserted into a connector (e.g., as described below). Figure 6 The length of the connector 234 shown in FIG. 1 and electrically coupled thereto minimizes exposure of the conductor 202 outside the connector.

[0040] In addition, the shrink joint 210 can include a secondary gasket 228 that can be positioned over the electrically insulating layer 204 of the second portion 200B of the heating cable 200 (e.g., after first applying grease (not shown) to the electrically insulating layer 204). More specifically, along the second portion 200B, the outer semiconductive layer 208 can be removed to expose a length of the electrically insulating layer 204, grease 214 can be applied to at least a portion of the exposed length of the electrically insulating layer 204, and the secondary gasket 228 can be shrunk over the electrically insulating layer 204 and any grease 214. As noted above, the grease can fill potential air pockets that may exist between the gasket 228 and the electrically insulating layer 204.

[0041] Secondary gasket 228 can be substantially identical to primary gasket 216. Specifically, secondary gasket 228 can be cold shrink tubing, such as silicone cold shrink tubing. In some embodiments, secondary gasket 228 can be push-on tubing or heat shrink tubing. Secondary gasket 228 can be shrunk onto electrically insulating layer 204 of second portion 200B in the same manner that primary gasket 216 is shrunk onto electrically insulating layer 204 of first portion 200A. Furthermore, second segment 202B of conductor 202 can be exposed and extend substantially the same length as first segment 202A of conductor 202.

[0042] Now refer to Figure 2-Figure 4 as well as Figure 5, the sizes of the main pad 216 and the secondary pad 228 can be appropriately set to allow the external cold shrink tube 230 of the joint 210 to cover and protect the heating cable 200. The external cold shrink tube 230 can be a silicone cold shrink tube. The external cold shrink tube 230 can be pre-formed into a predetermined shape and then pre-expanded on the inner spiral 232, and the function of the inner spiral 232 is similar to the inner spiral 218 described above. The inner spiral 232 can also include a tear cord portion 233. Similar to the main pad 216 and the secondary pad 228, as the inner spiral 232 is removed (for example, using the tear cord portion 233), the external cold shrink tube 230 shrinks. However, the external cold shrink tube 230 may not shrink beyond the predetermined shape, which limits what shape the external cold shrink tube 230 can form a suitable assembly around.

[0043] If the primary gasket 216, the secondary gasket 228, and the outer semiconductive layer 208 do not have a large enough diameter, the outer cold shrink tubing 230 may not shrink far enough to form the outer surfaces of the primary gasket 216, the secondary gasket 228, and the outer semiconductive layer 208 (e.g., to form a sufficiently compressed seal around the primary gasket 216, the secondary gasket 228, and the outer semiconductive layer 208) and provide protection from elements such as water or other liquids. For example, the diameter D1 of the shrunken primary gasket 216 (e.g., Figure 4 ) and the diameter D2 of the collapsed sub-pad 228 (e.g., as Figure 4 The outer cold shrink tubing 230 may be configured to shrink far enough to compress against the outer surfaces of the primary pad 216, the secondary pad 228, and the outer semiconducting layer 208 and provide protection from elements such as water or other liquids, as long as the diameters D1 and D2 are within a predetermined margin of diameter D3, such as one millimeter. Grease may also be applied to fill potential air pockets that may exist due to a mismatch between D1 and D3 and / or D2 and D3. As noted above, if air pockets are not adequately eliminated, electrical discharges may occur, particularly for cables operating at voltages of approximately five kilovolts or higher.

[0044] In addition, now refer to Figure 2-Figure 5 as well as Figure 6 Shrink joint 210 may further include a connector 234, such as a shear bolt connector. For example, connector 234 may be a tin-plated aluminum shear bolt connector, a nickel-plated shear bolt connector, or a copper shear bolt connector. Connector 234 may also be a crimp connector. Connector 234 may receive first segment 202A and second segment 202B of each conductor 202 to electrically connect conductors 202A and 202B.

[0045] In some embodiments, the connector 234 can include a body 236 and any number of fasteners that can secure the first segment 202A and the second segment 202B of the conductor 202 to the body 236. For example, the connector 234 can include a first fastener 238 and a second fastener 240. The first fastener 238 and the second fastener 240 can each be a bolt, such as a breakaway bolt or a screw. The first fastener 238 and the second fastener 240 can each be rotated or otherwise driven into the body 236 and abut against the first segment 202A and the second segment 202B, respectively, thereby physically securing and electrically coupling the first segment 202A and the second segment 202B to the body 236 and, in turn, to the connector 234. Thus, the connector 234 can electrically couple the first portion 200A of the heating cable 200 to the second portion 200B of the heating cable.

[0046] The outer cold shrink tubing 230 can be sized large enough to fit over the connector 234 and can be retracted far enough to squeeze or compress against the outer surface of the primary pad 216, the secondary pad 228, and the outer semiconductive layer 208, as described above. The presence of the primary pad 216 and the secondary pad 228 can reduce how far the outer cold shrink tubing 230 needs to be retracted compared to a joint that does not include the pads 216, 228. Thus, a wider range of cold shrink tubing can be used as the outer cold shrink tubing 230 because the shrinkage requirements are reduced, which can also result in a more cost-effective joint 210 and / or allow the use of already existing commercial cold shrink tubing.

[0047] Now refer to Figure 2-Figure 6 as well as Figure 7 As described above, the external cold shrink tubing 230 can be positioned over the primary pad 216, the secondary pad 228, the connector 234, and at least a portion of the outer semiconductive layer 208, and the external cold shrink tubing 230 can be shrunk by removing the inner spiral 232. Before the external cold shrink tubing 230 is shrunk, another layer of grease (not shown) can be applied to the outer surfaces of the primary pad 216, the secondary pad 228, and the connector 234 to eliminate potential air pockets. Thus, the joint 210 can include grease applied to the outer surfaces of the primary pad 216, the secondary pad 228, and the connector 234. The external cold shrink tubing 230 (and thus the joint 210) can then provide protection for the conductor 202 and the connector 234 from elements such as water.

[0048] Additionally, in some embodiments, the outer cold shrink tubing 230 may include an outermost semiconductive layer 244 that may prevent or reduce discharges that may occur in the cold shrink joint. Certain cables, such as in-line skin effect heating cables operating at five kilovolts or above, may include an outer semiconductive layer (e.g., Figure 1The outer semiconductive layer 108 shown contacts the inner surface of the heat pipe being heated and reduces or eliminates corona or partial discharge without interfering with the electrical relationship between the in-line skin-effect heating cable and the heat pipe that enables skin-effect heating. The heat pipe acts as a ground for the outer semiconductive layer. Therefore, to reduce or eliminate discharges in the junction 210, the outermost semiconductive layer 244 of the outer cold shrink tubing 230 can be arranged to be electrically connected to a suitable ground. For example, the junction 210 can be electrically connected to the heat pipe via a junction box 264.

[0049] More specifically, Figure 8 A junction box 264 is shown having a top portion 272 and a bottom portion 268. Figure 8 As shown, the top portion 272 may be removed and the bottom portion 268 may receive the shrink joint 210 . Figure 9 The top portion 272 of the junction box 264 is shown attached to the bottom portion 268, and the shrink joint 210 is located in the junction box 264. Figure 9 In FIG. 1 , the positions of the cold shrink joint 210 , the first portion 200A of the heating cable 200 , and the second portion 200B of the heating cable 200 within the junction box are indicated by dotted lines.

[0050] In some applications, the junction box 264 can be welded to the first heating tube 276 and the second heating tube 280. The first heating tube 276 and the second heating tube 280 can form a larger heating tube that transfers heat to a pipeline (e.g., an oil pipeline, a sulfur pipeline, etc.). The junction box 264 can completely enclose the cold shrink joint 210. The joint 210 and the junction box 264, in combination, can form a joint system for the heating cable 200 (e.g., a skin effect heating cable). The junction box 264 is electrically connected to the heating tubes 276, 280 due to the welding connection, and the heating tubes 276, 280 can serve as a ground for the cold shrink joint 210.

[0051] For example, the junction box 264 is typically metallic and electrically conductive. In some embodiments, the inner surface 266 of the junction box 264 is not painted or otherwise treated to reduce or eliminate conductivity within the junction box 264. When the outermost semi-conductive layer 244 of the outer cold shrink tubing 230 is in contact with the inner surface 266 of the junction box 264 (and is therefore in direct electrical communication with the junction box 264) and the junction box 264 is in electrical communication with the heating tubes 276, 280, the outer cold shrink tubing 230 can be electrically conductive to the outer semi-conductive layer (e.g., Figure 1 The outer semiconducting layer 108 shown is similarly reduced or eliminated in a similar manner.

[0052] Another method of achieving grounding in some embodiments is to place the outer semiconductive layer 244 of the outer cold shrink tubing 230 in electrical communication with the outer semiconductive layer 208 of the heating cable 200. To implement this method, a conductive jumper, such as a piece of conductive tape, metallic braid, or a conductive wire sleeve, can be positioned between the outer semiconductive layer 244 of the outer cold shrink tubing 230 and the outer semiconductive layer 208 of the heating cable 200.

[0053] Figure 10-12 Another cold shrink joint 310 is shown according to some embodiments for joining a first portion 300A of a heating cable 300 with a second portion 300B of a heating cable 300 having a conductor 302, an insulating layer 304, and an outer semiconducting layer 308. The cold shrink joint 310 may include Figure 2-Figure 7 Specifically, the cold shrink joint 310 may include an external cold shrink tube 330 that may be substantially the same as the external cold shrink tube 230 described above, a primary gasket 316 that may be substantially the same as the primary gasket 216 described above, a secondary gasket 328 that may be substantially the same as the secondary gasket 228 described above, and a connector 334 that may be substantially the same as the connector 234 described above. Figure 10 The cold shrink joint 310 is shown installed, particularly with the outer cold shrink tubing 330 covering the other components of the cold shrink joint 310 .

[0054] Figure 11 and Figure 12 The installed cold shrink joint 310 is shown with the outer cold shrink tubing 330 cut away and removed to show the other components of the cold shrink joint 310, including the connector 334, the primary pad 316, and the secondary pad 328. As described above, the outer cold shrink tubing 330 may include a semi-conductive layer on its outer surface. Figure 11 and Figure 12 As shown, the external cold shrink tube 330 may include a first stress cone 352, a second stress cone 354, and a connector interface 356 along its interior. In some embodiments, the first stress cone, the second stress cone, and the connector interface may also be included in Figure 7 The portion of the outer cold shrink tube 330 that does not include the first stress cone 352 , the second stress cone 354 , the connector interface 356 , and the semi-conductive coating may include an insulator material 350 . Figure 12 A closer view of the first stress cone 352 and the connector interface 356 is shown.

[0055] Connector interface 356 and stress cones 352 and 354 can each comprise the same semiconductive material, which can be a semiconductive silicone. Connector interface 356 can be positioned on and in contact with connector 334. For example, connector 334 can be a compression connector comprising a metal or semiconductive collar that provides an electrical connection between connector 334 and semiconductive connector interface 356. Furthermore, first stress cone 352 can contact both primary pad 316 and outer semiconductive layer 308 of first cable portion 300A. Second stress cone 354 can contact both secondary pad 328 and outer semiconductive layer 308 of second cable portion 300B.

[0056] Connector 334 can be centered and in contact with connector interface 356 without contacting insulation material 350. More specifically, because connector interface 356 is in electrical contact with connector 334, during operation of the heating cable, connector interface 356 is at the heating cable's operating voltage. On the other hand, because stress cones 352, 354 are electrically connected to the cable's outer semiconductive layer, they are at ground potential. The insulating material section 350 between connector interface 356, which is at operating voltage, and stress cones 352, 354, which are at ground potential, has sufficient creepage distance and insulation thickness to withstand high electrical stresses in this area. Stress cones 352, 354 can thus reduce high electrical stresses that occur at the semiconductive edges of cable 300.

[0057] Figure 13 Shows something like Figure 8 The junction box 364 of the junction box 264 is removed, and the top portion 372 of the junction box 364 is removed, and the shrink joint 310 is arranged in the bottom portion 368 thereof. Figure 14 The top portion 372 of the junction box 364 is shown attached to the bottom portion 368, and the shrink joint 310 is located in the junction box 364. Figure 14 , the locations of the cold shrink joint 310, the first portion 300A of the heating cable 300, and the second portion 300B of the heating cable 300 within the junction box 364 are indicated by dashed lines. The joint 310, in combination with the junction box 364, can form a joint system for the heating cable 300 (e.g., a skin effect heating cable).

[0058] Junction box 364 can be welded to first and second heating tubes 376, 380, thereby being in electrical communication with heating tubes 376, 380. First and second heating tubes 376, 380 can form a larger heating tube that transfers heat to a pipeline (e.g., an oil pipeline, a sulfur pipeline, etc.). Junction box 364 can completely enclose shrink joint 310, and heating tubes 376, 380 can serve as a ground for shrink joint 310.

[0059] More specifically, similar to the junction box 264 described above, the junction box 364 is generally metallic and electrically conductive. In some embodiments, the interior surface 366 of the junction box 364 is not painted or otherwise treated to reduce or eliminate conductivity within the junction box 364. When the outer semi-conductive layer 344 of the outer cold shrink tubing 330 is in contact with the interior surface 366 of the junction box 364 and the junction box 364 is in electrical communication with the heating tubes 376, 380, the outer cold shrink tubing 330 can be electrically conductive to the outer semi-conductive layer (e.g., Figure 1 The outer semiconducting layer 108 shown is similarly reduced or eliminated in a similar manner.

[0060] In some embodiments, another approach is to place the outer semiconductive layer 344 of the outer cold shrink tubing 330 in electrical communication with the outer semiconductive layer 308 of the heating cable 300. To implement this approach, a conductive jumper, such as a piece of conductive tape, metallic braid, or a conductive wire sleeve, can be positioned between the outer semiconductive layer 344 of the outer cold shrink tubing 330 and the outer semiconductive layer 308 of the heating cable 300.

[0061] In view of the above, in some embodiments, a method for installing the cold shrink joint 310 may include removing (e.g., by peeling) the outer semiconductive layer 308 along the first portion 300A of the heating cable 300 to expose a predetermined length of the insulation layer 304, and installing the main pad 316 on the insulation layer 304. The predetermined length may be approximately equal to the length of the main pad 316 plus a second predetermined length that the conductor 302 needs to be exposed to insert into the connector 334. The predetermined length may be slightly longer (e.g., ten percent) than the length of the main pad 316 plus the second predetermined length.

[0062] The method may include further removing the insulating layer 304 to expose a second predetermined length of the conductor 302. The method may include installing a secondary pad 328 on the second portion 300B and exposing a length of the conductor 302 included in the second portion 300B in the same manner as the primary pad 316 and the exposed conductor 302 in the first portion.

[0063] The method may include electrically coupling the first portion 300A to the second portion 300B by connecting the conductor 302 of the first portion 300A and the conductor 302 of the second portion 300B via the connector 334. The method may include positioning and installing (e.g., by shrinking) an external cold shrink tubing 330 over the connector 334, the primary gasket 316, and the secondary gasket 328. Prior to installing the external cold shrink tubing 330, the connector interface 356 may be positioned on the connector 334, the first stress cone 352 may be positioned on the primary gasket 316 and the outer semiconductive layer 308 of the first portion 300A, and the second stress cone 354 may be positioned on the secondary gasket 328 and the outer semiconductive layer 308 of the second cable portion 300B.

[0064] After the outer cold shrink tube 330 shrinks, the connector interface 356 can make contact (e.g., electrical contact) with the connector 334, the first stress cone 352 can make contact with the primary pad 316 and the outer semiconductive layer 308 of the first portion 300A, and the second stress cone 354 can make contact with the secondary pad 328 and the outer semiconductive layer 308 of the second cable portion 300B.

[0065] After installation, the method can include placing the cold shrink joint 310, and more specifically the outer cold shrink tubing 330, in the bottom portion 368 of the junction box 364. The method can include securing the top portion 372 of the junction box 364 to the bottom portion 368. In some embodiments, the method can include pulling the first portion 300A and the second portion 300B through the first and second heating tubes 376, 380, respectively, and positioning the cut ends of the first and second portions 300A, 300B in and / or near the junction box before installing the cold shrink joint 310. Additionally, the method can include welding the junction box 364 to the heating tubes 376, 380.

[0066] As described above, the joint 210 / 310 of some embodiments may include a primary gasket, a secondary gasket, grease applied between a length of the electrical insulation layer and the primary gasket, grease applied between a length of the electrical insulation layer and the secondary gasket, a connector, external cold shrink tubing, and any grease covering the primary gasket, the secondary gasket, and the connector. The selection of these components, and the material properties of these components, enables the joint to cost-effectively electrically couple high-voltage heating cables, such as in-line skin-effect heating cables, be easily installed by qualified technicians, and be capable of withstanding relatively high temperatures.

[0067] Notably, when cold shrink tubing is used as the primary gasket, secondary gasket, and outer cold shrink tubing, the joint does not require the use of tape. For example, installing tape is often labor-intensive and process-intensive, and a joint including tape may be more difficult to install than a joint including cold shrink tubing. Additionally, in some embodiments, the connector may be a shear bolt connector, which may be easier to install than other connector types, such as crimp connectors.

[0068] Furthermore, the size of the joint can provide a cost-effective joint solution. Figure 7 , the diameter of the joint 210 is only slightly larger at the portion of the cold shrink tubing 230 that is located on the connector 234. Therefore, using a shear bolt connector having a diameter close to the diameter of the cable 100 as the connector 234 can reduce the size of the joint 210 compared to other joints that use other connectors. The relatively small size of the joint 210 can allow the joint 210 to be positioned in a smaller (and potentially less expensive) junction box than other joints, potentially reducing costs for the customer. The joint 210 also does not require molded push-on tubing (e.g., silicone push-on tubing) that can be difficult to install reliably.

[0069] The joints of certain embodiments may also be rated for higher temperatures than other commercially available joints. More specifically, the primary gasket, secondary gasket, and outer cold shrink tubing described above may include silicone and, therefore, may be rated for higher temperatures (e.g., 150°C) than the components included in other commercial joint kits. For example, commercial EPDM push-on tubing is typically rated for temperatures of only about 90-105°C. As another example, many commercially available semi-conductive adhesives or tapes are not rated for use up to 150°C. Thus, the joints may be configured to withstand higher temperatures than other joint kits.

[0070] The joints of some embodiments may also be used with certain skin effect heating cables, such as in-line skin effect heating cables, for which other joint kits are not suitable. For example, some joint kits cannot be used with skin effect heating cables because these joint kits use an external metal ground. In addition, currently available joints are not suitable for in-line skin effect heating cables due to size limitations (e.g., they do not fit within a junction box or cannot be shrunk sufficiently to the diameter of the skin effect heating cable). The joints described herein are configured to operate with skin effect heating cables and fit within a junction box, thereby providing an improvement over existing joints. The primary pad, secondary pad, and external cold shrink tubing allow electrical contact between the joint and the junction box and the heat pipes welded to the junction box, which allows for necessary electrical discharge during operation of the heater cable.

[0071] Those skilled in the art will appreciate that although the invention has been described above with reference to specific embodiments and examples, the invention is not necessarily limited thereto, and that many other embodiments, examples, uses, modifications and deviations from the embodiments, examples and uses are intended to be covered by the appended claims.

Claims

1. A splicing system for a skin effect heating cable having an insulation layer and comprising a first portion at least partially disposed within a first heating tube and a second portion at least partially disposed within a second heating tube, the splicing system comprising: The joint comprises: a primary cold shrink pad that shrinks onto a first section of the insulation layer of the first portion of the heating cable; a secondary cold shrink pad, the secondary cold shrink pad shrinking onto the second section of the insulation layer of the second portion of the heating cable; a connector electrically coupled to a first conductor of the first portion of the heating cable and a second conductor of the second portion of the heating cable; and an external cold shrink tubing comprising an outer semi-conductive layer, the external cold shrink tubing being shrunk onto the primary cold shrink pad, the secondary cold shrink pad, and the connector; and A metal junction box is welded to the first heating tube and the second heating tube and is electrically connected to the first heating tube and the second heating tube. The metal junction box accommodates the joint and is electrically connected to the outer semiconductive layer of the outer cold shrink tube.

2. The joining system according to claim 1, wherein: The connector is a shear bolt connector.

3. The joining system of claim 1 , wherein: The main cold shrink pad includes a cold shrink silicone tube.

4. The joining system of claim 1 , wherein: The secondary cold shrink pad includes a cold shrink silicone tube.

5. The joining system of claim 1 , wherein: The external cold shrink tube is a cold shrink silicone tube.

6. The joining system of claim 1, wherein: The skin effect heating cable operates at a voltage of five kilovolts or more.

7. The joining system of claim 1, wherein the skin effect heating cable operates at a voltage of ten thousand volts or more.

8. The joining system of claim 1, wherein: The outer semiconductive layer of the outer cold shrink tubing is in electrical contact with the outer semiconductive layer of the heating cable.

9. The joining system of claim 1 , wherein: The primary cold shrink pad has a collapsed diameter approximately equal to the diameter of the outer semiconductive layer of the heating cable.

10. The joining system of claim 1, wherein: The primary cold shrink pad, the secondary cold shrink pad, and the outer cold shrink tubing comprise materials rated for at least 150 degrees Celsius.

11. The joining system of claim 1 , wherein: The heating cable includes a conductor having a size equal to or less than two American wire gauge.

12. The joining system of claim 1, wherein: The connector is a compression connector that includes a metallic or semi-conductive collar that provides an electrical connection between the connector and the connector interface of the external cold shrink tubing.

13. The joining system of claim 1, wherein: The heating cable includes an outer semiconductive layer, and the outer cold shrink tubing includes: a connector interface, the connector interface being in contact with the connector; a first stress cone in contact with the primary cold shrink pad and the outer semiconductive layer of the first portion of the heating cable; and A second stress cone is provided in contact with the secondary cold shrink pad and the outer semiconductive layer of the second portion of the heating cable.

14. A joint for a skin effect heating cable, the skin effect heating cable comprising an insulating layer and disposed in a heating tube, the joint comprising: a primary cold shrink pad that shrinks onto a first section of the insulation layer of a first portion of the heating cable; a secondary cold shrink pad, the secondary cold shrink pad shrinking onto the second section of the insulation layer of the second portion of the heating cable; a connector electrically coupled to the conductor of the first portion of the heating cable and the conductor of the second portion of the heating cable; as well as An external cold shrink tube is shrunk onto the primary cold shrink pad, the secondary cold shrink pad and the connector, and is in electrical contact with a metal junction box, and the metal junction box is electrically connected to the heating tube.

15. The joint according to claim 14, wherein The outer cold shrink tubing includes an outer semiconductive layer that is in electrical contact with the outer semiconductive layer of the heating cable.

16. The joint according to claim 14, wherein The connector is a shear bolt connector.

17. A method for installing a cold shrink joint on a skin effect heating cable, the method comprising: removing an outer semiconductive layer along a first portion of the heating cable to expose a first section of the insulation layer of the heating cable; installing a primary pad on at least a portion of the first segment of the insulating layer; removing the outer semiconductive layer along a second portion of the heating cable to expose a second section of the insulation layer of the heating cable; mounting a subgasket on at least a portion of the second segment of the insulating layer; Installing cold shrink tubes on the primary pad and the secondary pad; as well as The cold shrink tubing is arranged to be in electrical contact with the junction box.

18. The method of claim 17, further comprising coupling the first portion of the heating cable to the second portion of the heating cable with a connector.

19. The method according to claim 18, further comprising: Arranging the connector interface of the cold shrink tube on the connector; placing a first stress cone of the cold shrink tubing on the main pad and the outer semiconductive layer; as well as A second stress cone of the cold shrink tubing is disposed on the subgasket and the outer semiconductive layer.

20. The method of claim 17, further comprising applying grease to the at least a portion of the first section of the insulating layer before installing the main mat.

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