Patent Description:
A dynamic and static submarine cable generally includes a dynamic cable and a static cable that are connected. The dynamic cable is arranged in seawater and constantly moves under the influence of environmental factors such as wind, waves and currents, etc. The static cable is buried in the seabed, and is less affected by the environmental factors, and thus no constant motion is caused. With the development and utilization of marine resources, offshore platforms such as offshore oil and gas platforms, offshore wind turbines, wave energy generators, and tidal energy generators are gradually increasing, and the demand for dynamic and static submarine cables is also gradually increasing.

Due to different working conditions, structures of the dynamic cable and the static cable are different. Taking an armor layer as an example, generally the dynamic cable is subjected to more impact and wear than the static cable, so the number of armor layers of the dynamic cable is more than that of the static cable. In the related art, the dynamic cable and the static cable are generally produced separately, and then a service joint box is used to connect the dynamic cable and the static cable to form a dynamic and static submarine cable.

However, there is a long production cycle for the above-mentioned dynamic and static submarine cable.

<CIT> discloses a dynamic submarine cable and static submarine cable transition assembly and a preparation method thereof. The dynamic submarine cable and static submarine cable transition assembly is composed of a cable unit, an armored transition unit and a sheath transition unit. The dynamic submarine cable and the static submarine cable are respectively composed of a cable unit, an armored steel wire and a sheath, the dynamic submarine cable and the static submarine cable adopt the same cable unit, the cable units are continuous in the production and manufacturing process, and online transition of the cable units is mainly reflected in transition of the armored unit and the sheath unit.

<CIT> discloses a submarine power cable comprising: a power core including a conductor, wherein the conductor has a conductor joint in a joint region (R) of the power core, a main armour layer comprising a plurality of main armour wires arranged around the power core and extending in the axial direction of the power core, and a joint reinforcement armour layer comprising a plurality of joint reinforcement armour wires axially locked relative to the main armour wires, wherein the joint reinforcement armour layer is provided only in the joint region and arranged layered with the main armour layer, the joint reinforcement armour layer and the main armour layer thereby forming a dual-layer armour only in the joint region (R).

In view of the above problem, the present invention provides a dynamic and static submarine cable according to claim <NUM> and a method for manufacturing the same, to shorten the production cycle of the dynamic and static submarine cable, according to claim <NUM>.

In order to achieve the above purpose, embodiments of the present invention provide the following technical solutions.

The present invention provides a dynamic and static submarine cable, according to claim <NUM>. covering part of the transition device and welded to an outer peripheral surface of the.

The dynamic and static submarine cable provided by the present invention has the following advantages:
in the dynamic and static submarine cable provided by the embodiments of the present invention, the first armor layer is sleeved outside the dynamic section, the static section, and the transition section of the cable core, and the transition device is sleeved outside the first armor layer corresponding to the transition section. The second armor layer is sleeved outside the first armor layer corresponding to the dynamic section, and the first end of the second armor layer is welded to the outer peripheral surface of the transition device. With such arrangement, transition between the armor layer of the dynamic section and the armor layer of the static section can be realized through the connection of the transition device and the second armor layer, thereby ensuring continuity of a production process of the dynamic and static submarine cable. There is no need to separately produce the dynamic cable and the static cable at a time of producing the dynamic and static submarine cable, thereby shortening the production cycle.

The present invention provides a method manufacturing a dynamic and static submarine cable according to claim <NUM>.

The method for manufacturing the dynamic and static submarine cable provided by the present invention has the following advantages:
in the method for manufacturing the dynamic and static submarine cable provided by the embodiments of the present invention, the cable core is continuously produced, and the cable core is divided into the dynamic section, the static section and the transition section by setting the demarcation points. The first armor layer is stranded on the outer peripheral surface of the dynamic section, on the outer peripheral surface of the static section, and on the outer peripheral surface of the transition section. The heat transfer unit is formed on the outer peripheral surface of the first armor layer corresponding to the transition section, and the welding unit is sleeved on the outer peripheral surface of the heat transfer unit. The second armor layer is stranded on the outer peripheral surface of the first armor layer corresponding to the dynamic section, and the first end of the second armor layer covers part of the welding unit and is welded to the outer peripheral surface of the welding unit. With such arrangement, transition between the armor layer of the dynamic section and the armor layer of the static section can be realized through the connection of the welding unit and the second armor layer, and the dynamic and static submarine cable can be produced continuously without the need to separately produce the dynamic cable and the static cable, thereby shortening the production cycle.

In order to illustrate the technical solutions in the embodiments of the present invention or in the prior art more clearly, the drawings required for describing the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below show some embodiments of the present invention, and persons of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts.

A dynamic and static submarine cable generally includes a dynamic cable and a static cable that are connected. Both the dynamic cable and the static cable include a cable core and an armor layer covering the cable core. Since the dynamic cable is arranged in seawater and the static cable is buried in the seabed, the static cable is subjected to less impact and wear than the dynamic cable. Therefore, the number of armor layers of the static cable is generally less than that of the dynamic cable, rendering different structures of the dynamic cable and the static cable. In the related art, the dynamic cable and the static cable are generally produced separately, and then a service joint box is used to connect cable cores and armor layers of the dynamic cable and the static cable to realize transition between the dynamic cable and the static cable so as to form a dynamic and static submarine cable. However, separately producing the dynamic cable and the static cable increases the production cycle, and the process of connecting the cable cores and the armor layers is time-consuming, which further increases the production cycle. In addition, connecting the dynamic cable core and the static cable core by the service joint box increases transmission loss of cable cores.

In view of the above problems, a dynamic and static submarine cable provided by embodiments of the present invention includes a continuous cable core, where a first armor layer is arranged outside the cable core, a transition device is arranged on the first armor layer corresponding to a transition section of the cable core, and one end of a second armor layer is welded to the transition device, thereby realizing transition from double armor layers to one armor layer, and ensuring continuity of a production process of the dynamic and static submarine cable. In addition, the dynamic section and the static section can be in the same cable core, so that the dynamic and static submarine cable can be produced continuously without separate production, and thus there is no need to connect the dynamic cable core and the static cable core, thereby shortening the production cycle and reducing the transmission loss of the cable core.

In order to make the above objectives, features and advantages of the embodiments according to the present invention clearer and understandable, the following clearly and completely describes the technical solutions in the embodiments according to the present invention with reference to the accompanying drawings in the embodiments according to the present invention. Apparently, the described embodiments are only some but not all of the embodiments according to the present invention. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments according to the present invention without creative efforts shall fall within the protection scope of the present invention.

As shown in <FIG>, an embodiment of the present invention provides a dynamic and static submarine cable, including a cable core <NUM>, a first armor layer <NUM>, a transition device <NUM> and a second armor layer <NUM>. The cable core <NUM> includes a dynamic section <NUM>, a static section <NUM> and a transition section <NUM> connecting the dynamic section <NUM> and the static section <NUM>, and the dynamic section <NUM>, the static section <NUM> and the transition section <NUM> are of an integral structure. The first armor layer <NUM> is sleeved outside the dynamic section <NUM>, the static section <NUM> and the transition section <NUM>. The transition device <NUM> is sleeved outside the first armor layer <NUM> corresponding to the transition section <NUM>. The second armor layer <NUM> is sleeved outside the first armor layer <NUM> corresponding to the dynamic section <NUM>, and has a first end covering part of the transition device <NUM> and welded to an outer peripheral surface of the transition device <NUM>.

The first end of the second armor layer <NUM> is an end of the second armor layer <NUM> close to the static section <NUM>, and a dynamic and static submarine cable section corresponding to the static section <NUM> can be understood as a static cable, such as a section C as shown in <FIG>; a dynamic and static submarine cable section corresponding to the dynamic section <NUM> can be understood as a dynamic cable, such as a section A as shown in <FIG>; and a dynamic and static submarine cable section corresponding to the transition section <NUM> can be understood as a transition cable, such as a section B as shown in <FIG>. The transition device <NUM> may be ring-shaped, and the ring-shaped transition device <NUM> is sleeved outside the first armor layer <NUM> corresponding to the transition section <NUM>.

The dynamic and static submarine cable provided by the embodiment of the present invention has the cable core <NUM>. The dynamic section <NUM>, the static section <NUM> and the transition section <NUM> in the cable core <NUM> are of an integral structure. The first armor layer <NUM> is provided on an outside of the cable core <NUM>. By arranging the transition device <NUM> on the first armor layer <NUM> corresponding to the transition section <NUM>, and welding one end of the second armor layer <NUM> to the transition device <NUM>, the transition from the armor layer of the dynamic section to the armor layer of the static section can be completed, therefore, the continuity of a production process of the dynamic and static submarine cable is guaranteed. With such arrangement, the dynamic section and the static section can be in the same cable core, so that the dynamic and static submarine cable can be produced continuously without separate production, and thus there is no need to connect the dynamic cable core and the static cable core, thereby shortening the production cycle and reducing the transmission loss of the cable core <NUM>.

Referring to <FIG>, the dynamic and static submarine cable provided by the embodiment of the present invention includes the cable core <NUM>. The cable core <NUM> includes a plurality of electrical units <NUM> and a plurality of optical units <NUM>, and the plurality of electrical units <NUM> and the plurality of optical units <NUM> are stranded.

The electrical units <NUM> are applicable to conducting electricity and transmitting signals, and the number of the electrical units <NUM> may be <NUM>, <NUM>, <NUM>, etc. In this embodiment, the number of the electrical units <NUM> is <NUM>. The number of the optical units <NUM> may be <NUM>, <NUM>, <NUM>, etc. In this embodiment, the number of the optical units <NUM> is <NUM>.

Referring to <FIG>, in a specific embodiment, each electrical unit <NUM> includes, from inside to outside in a radial direction, an electrical unit core, an inner semi-conductive shielding layer <NUM>, an insulating layer <NUM>, an outer semi-conductive shielding layer <NUM>, a semi-conductive water-blocking layer <NUM>, a metal shielding layer <NUM> and a phase-splitting sheath layer <NUM>, where the electrical unit core includes a plurality of stranded conductors <NUM>. The conductors <NUM> may be copper conductors, aluminum conductors, or the like.

The inner semi-conductive shielding layer <NUM> covers an outer peripheral surface of the electrical unit core, and may be used to avoid partial discharge between the conductors <NUM> and the insulating layer <NUM>. The insulating layer <NUM> covers an outer peripheral surface of the inner semi-conductive shielding layer <NUM>, and may be used to insulate the electrical unit core from external environment or adjacent electrical unit cores, thereby ensuring electrical performance of the dynamic and static submarine cable. Exemplarily, the insulating layer <NUM> may be formed by extrusion cladding.

The outer semi-conductive shielding layer <NUM> covers an outer peripheral surface of the insulating layer <NUM>, and may be used to prevent partial discharge between the insulating layer <NUM> and the metal shielding layer <NUM> due to defects such as cracks on a surface of the insulating layer <NUM>. The semi-conductive water-blocking layer <NUM> covers an outer peripheral surface of the outer semi-conductive shielding layer <NUM>, and may play a role of blocking water. The metal shielding layer <NUM> covers an outer peripheral surface of the semi-conductive water-blocking layer <NUM>. The metal shielding layer <NUM> may be a copper tape shielding layer, a steel tape shielding layer, an aluminum-plastic composite tape shielding layer and other composite tape shielding layers, and can shield electromagnetic interference. The phase-splitting sheath layer <NUM> covers an outer peripheral surface of the metal shielding layer <NUM>, this can avoid direct contact between metal shielding layers <NUM> of the plurality of electrical units, thereby avoiding abrasion between the metal shielding layers <NUM> of the plurality of electrical units and playing a role of water resistance and blocking water. In this embodiment, the phase-splitting sheath layer <NUM> is an extruded sheath layer.

The optical unit <NUM> provided by an embodiment of the present invention includes an optical fiber <NUM> and a protective layer covering an outer peripheral surface of the optical fiber <NUM>, and the optical unit may be used to transmit signals. Exemplarily, referring to <FIG>, the optical unit includes an outer casing <NUM> and a plurality of optical fibers <NUM> arranged inside the outer casing. The outer casing may be a stainless steel tube. Water-blocking fillings <NUM> are further arranged between the plurality of optical fibers <NUM> in the outer casing <NUM>. Along a radial direction of the outer casing <NUM>, an outer peripheral surface of the outer casing <NUM> is covered sequentially with an inner semi-conductive sheath <NUM>, an optical unit armor layer <NUM>; a water-blocking tape <NUM>; and an outer semi-conductive sheath <NUM>.

In some embodiments, not covered by claims, the cable core <NUM> further includes a central reinforcing member, and the plurality of optical units <NUM> and the plurality of electrical units <NUM> are stranded around the central reinforcing member. The central reinforcing member may be a metal wire or a non-metallic wire. Tension resistance and balance of the cable core <NUM> can be enhanced by arranging the central reinforcing member.

Further, in embodiments not covered by claims, the cable core <NUM> further includes fillers <NUM> filled in stranded gaps between the plurality of optical units <NUM> and the plurality of electrical units <NUM>, and the fillers <NUM> may be filling strips, filling ropes and the like.

Referring to <FIG>, in some specific embodiments, the cable core <NUM> further includes a first sheath layer <NUM>, and the first sheath layer <NUM> covers an outside of the stranded electrical units <NUM> and optical units <NUM>. Arrangement of the first sheath layer <NUM>, not covered by claims, can ensure water-blocking performance of the cable core <NUM>. In this embodiment, the first sheath layer <NUM> is an extruded sheath layer.

Referring to <FIG>, the cable core <NUM> provided by the embodiment of the present invention axially includes the dynamic section <NUM>, the static section <NUM> and the transition section <NUM> connecting the dynamic section <NUM> and the static section <NUM>, and the dynamic section <NUM>, the static section <NUM> and the transition section <NUM> are of an integral structure, where the dynamic section <NUM> corresponds to a dynamic cable, and the static section <NUM> corresponds to a static cable. With such arrangement, during the manufacturing process, cable cores of the dynamic cable and the static cable can be continuously produced without separate manufacturing, thereby shortening the production cycle. There is also no need to connect the dynamic cable core and the static cable core, thereby reducing transmission loss of the cable core <NUM> and improving performance stability of the cable core <NUM>.

The first armor layer <NUM> is sleeved outside the dynamic section <NUM>, the static section <NUM> and the transition section <NUM>, and the first armor layer <NUM> is continuous. Both the first armor layer <NUM> and the second armor layer <NUM> may be formed by stranding or braiding metal wires such as steel wires. With such arrangement, in the manufacturing process, the first armor layer <NUM> of the dynamic and static submarine cable can be continuously produced without separate manufacturing, thereby shortening the production cycle.

Referring to <FIG>, <FIG>, the dynamic and static submarine cable provided by the embodiment of the present invention further includes the transition device <NUM> and the second armor layer <NUM>. The transition device <NUM> is sleeved outside the first armor layer <NUM> corresponding to the transition section <NUM>. The second armor layer <NUM> is sleeved outside the first armor layer <NUM> corresponding to the dynamic section <NUM>. The first end of the second armor layer <NUM> covers part of the transition device <NUM>, and is welded to the outer peripheral surface of the transition device <NUM>. With such arrangement, transition between the armor layer of the dynamic cable and the armor layer of the static cable can be realized.

Further, in embodiments not covered by claims, an inner cushion layer <NUM> may also be arranged between the second armor layer <NUM> and the first armor layer <NUM>. With such arrangement, direct contact between the second armor layer <NUM> and the first armor layer <NUM> can be avoided, and mutual abrasion between the second armor layer <NUM> and the first armor layer <NUM> is thereby avoided.

Referring to <FIG>, in some embodiments, an outer peripheral surface of the second armor layer <NUM> is further covered with a second sheath layer <NUM>. The second sheath layer <NUM> may be an extruded sheath layer, and material of the second sheath layer <NUM> can be PE material. An outer peripheral surface of the first armor layer <NUM> corresponding to the static section <NUM> is further covered with a third sheath layer <NUM>. The third sheath layer <NUM> may be a wrapping sheath layer, and material of the third sheath layer <NUM> may be PP winding rope.

According to the invention, referring to <FIG>, the transition device <NUM> includes a heat transfer unit and a welding unit <NUM>. The heat transfer unit covers an outside of the first armor layer <NUM> corresponding to the transition section <NUM>, and the welding unit <NUM> is an annular structure and is sleeved outside the heat transfer unit. The first end of the second armor layer <NUM> is welded to an outer peripheral surface of the welding unit <NUM>. The heat transfer unit can release heat during a welding process, and at the same time acts as an isolation buffer layer to ensure welding quality. The heat transfer unit is a metal tape wrapped around an outer peripheral surface of the first armor layer <NUM> corresponding to the transition section <NUM>.

In some possible embodiments, an inner peripheral surface and the outer peripheral surface of the welding unit <NUM> are respectively arranged with an anti-corrosion coating. By arranging the anti-corrosion coating, corrosion resistance of the welding unit <NUM> can be improved, thereby increasing service life of the welding unit <NUM>. Exemplarily, material of the anti-corrosion coating is a composite material with good stability, which can maintain good anti-corrosion performance in both high temperature and low temperature environments.

Referring to <FIG>, according to the invention, the welding unit <NUM> is of a half type, including two half-ring parts <NUM>. The two half-ring parts <NUM> are of a split structure. Inner ring surfaces of the two half-ring parts <NUM> are opposite, and two ends of one half-ring part <NUM> along a circumferential direction thereof are connected to two ends of the other half-ring part <NUM> along a circumferential direction thereof in a one-to-one relationship. Exemplarily, a mode of connecting the two half-ring parts <NUM> is welding. With such arrangement, the welding unit <NUM> can be directly sleeved outside the heat transfer unit, without inserting and moving the welding unit <NUM> from one end of the dynamic and static submarine cable to the outside of the heat transfer unit along an axis of the dynamic and static submarine cable, and the operation is thus more convenient.

Further, along an axial direction of each half-ring part <NUM>, each half-ring part <NUM> includes a welding fixing area <NUM> and two smooth transition areas <NUM> respectively connected to two ends of the welding fixing area <NUM>. A thickness of the welding fixing area <NUM> is greater than thicknesses of the smooth transition areas <NUM>. The first end of the second armor layer <NUM> is welded to an outer peripheral surface of the welding fixing area <NUM>. With such arrangement, heat generated during a process of welding the first end of the second armor layer <NUM> can be better transferred.

Referring to <FIG>, in some specific embodiments, along the axial direction of each half-ring part <NUM>, the thickness of the half-ring part <NUM> changes continuously, that is, the thicknesses at junctions between the smooth transition areas <NUM> and the welding fixing area <NUM> do not change abruptly.

Further, referring to <FIG>, on an axial cross-section of each half-ring part <NUM>, the thicknesses of the smooth transition areas <NUM> decrease linearly along a direction away from the welding fixing area <NUM>. With such arrangement, metal wires at the first end of the second armor layer <NUM> can better fit to the welding unit <NUM>, thereby improving strength and stability of the welding.

Further, along the axial direction of each half-ring part <NUM>, the thickness of the welding fixing area does not change. On the axial cross-section of each half-ring part <NUM>, a minimum thickness of each of the smooth transition areas <NUM> is <NUM>% of the thickness of the welding fixing area <NUM>. The axial cross-section is a cross section of an axis passing through the half-ring part <NUM>. Referring to <FIG>, the minimum thickness of the smooth transition areas <NUM> is at ends of the smooth transition areas <NUM> away from the welding fixing area <NUM>. Such arrangement can not only make the metal wires at the first end of the second armor layer <NUM> better fit to the welding unit <NUM>, but also rapidly conduct and reduce welding heat and avoid damage to a structure of the cable core <NUM>.

In some embodiments, the half-ring part <NUM> has a middle part protruding outwards, and is presented in a circular arch shape. Along the axial direction of the half-ring part <NUM>, a thickness of the circular arch shaped structure located at an edge of the half-ring part is equal to <NUM>% of a thickness of the circular arch shaped structure located at a middle of the half-ring part.

Exemplarily, a welding point between the first end of the second armor layer <NUM> and the welding fixing area <NUM> is further coated with an anti-corrosion coating, so as to improve anti-corrosion performance at the welding point. For the material of the anti-corrosion coating, reference may be made to the above description.

In some other specific embodiments, referring to <FIG>, along the axial direction of the half-ring part <NUM>, the thickness of the welding fixing area <NUM> and the thicknesses of the smooth transition areas <NUM> are all constant, and the thicknesses of the smooth transition areas <NUM> are equal to <NUM>% of the thickness of the welding fixing area <NUM>, and a transition portion is further arranged between the welding fixing area <NUM> and each smooth transition area <NUM>.

Claim <NUM> of the present invention further provides a method for manufacturing a dynamic and static submarine cable, including:.

Neither separate production of the dynamic cable and the static cable nor connection of the dynamic cable core and the static cable core is required by the method for manufacturing the dynamic and static submarine cable provided by the embodiment, thereby shortening the production cycle and reducing the transmission loss of the cable core.

Exemplarily, for structures and materials of the cable core and the welding unit in the above-mentioned method embodiments, reference may be made to the above-mentioned product embodiments, which will not be repeated here.

According to the invention, in the step of having the welding unit sleeved on the outer peripheral surface of the heat transfer unit, the welding unit includes two half-ring parts. The two half-ring parts are of a split structure. Inner ring surfaces of the two half-ring parts are opposite, and two ends of one half-ring part along the circumferential direction thereof are connected to two ends of the other half-ring part along the circumferential direction thereof in a one-to-one relationship. Exemplarily, a spot welding machine may be used to weld the two half-ring parts, so as to fix a position of the welding unit.

Exemplarily, in the step of welding the first end of the second armor layer to the outer peripheral surface of the welding unit, the first end of the second armor layer is welded to the welding fixing area of the welding unit, with welding points evenly distributed. During the welding process, metal wires at the first end of the second armor layer fit snugly to the smooth transition areas to ensure a reliable and stable welding process. Further, reservation and confirmation of a position of the second armor layer are also included before welding. The welding position is located in the middle of the welding fixing area. After the welding is completed, an anti-corrosion coating may be applied to outsides of the welding points.

After the step of welding the first end of the second armor layer to the outer peripheral surface of the welding unit, the following are further included:.

Exemplarily, for structures of the second sheath layer and the third sheath layer, reference may be made to the above-mentioned product embodiments, which will not be repeated here.

In some embodiments, not coverdd by claims, armor layers of the dynamic and static submarine cable include not only the first armor layer and the second armor layer, but also a third armor layer, a fourth armor layer and so on. At this point, after the step of welding the first end of the second armor layer to the outer peripheral surface of the welding unit, the following is further included:
having a further transition device sleeved outside the second armor layer, where the further transition device may be sleeved at any position outside the second armor layer, and for the structure of the further transition device, reference may be made to the above-mentioned product embodiments, which will not be repeated here; and then stranding the third armor layer on the outer peripheral surface of the second armor layer, and welding a first end of the third armor layer to an outer peripheral surface of this outermost welding unit, with a second end of the third armor layer aligned with an end of the second armor layer. Similarly, the above steps may be repeated when more armor layers such as a fourth armor layer and a fifth armor layer are included.

Embodiments or implementations in the present specification are described in a progressive manner. Description of each embodiment focuses on a difference from other embodiments, and references may be made to each other for same or similar parts among respective embodiments.

Those skilled in the art should understand that in the disclosure of the present invention, terms such as "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer", etc. refer to orientations or positional relationships based on orientations or positional relationships illustrated in the accompanying drawings, which are only to facilitate and simplify descriptions of the present invention, rather than to indicate or imply that the system or element referred to must be of a particular orientation or must be constructed and operate in a particular orientation, and therefore the above terms should not be construed as limiting the present invention.

Claim 1:
A dynamic and static submarine cable, comprising:
a cable core (<NUM>) comprising:
a dynamic section (<NUM>),
a static section (<NUM>), and
a transition section (<NUM>) connecting the dynamic section (<NUM>) and the static section (<NUM>),
wherein the dynamic section (<NUM>), the static section (<NUM>), and the transition section (<NUM>) are of an integral structure;
a first armor layer (<NUM>) sleeved outside the dynamic section (<NUM>), the static section (<NUM>) and the transition section (<NUM>); and
a second armor layer (<NUM>) sleeved outside the first armor layer (<NUM>) corresponding to the dynamic section (<NUM>),
characterized by further comprising:
a transition device (<NUM>) sleeved outside the first armor layer (<NUM>) corresponding to the transition section (<NUM>); and
the second armor layer (<NUM>) having a first end covering part of the transition device (<NUM>) and welded to an outer peripheral surface of the transition device (<NUM>);
wherein the transition device (<NUM>) comprises a heat transfer unit and a welding unit (<NUM>), and the heat transfer unit covers an outside of the first armor layer (<NUM>) corresponding to the transition section (<NUM>);
the welding unit (<NUM>) is of an annular structure and is sleeved outside the heat transfer unit; and
the first end of the second armor layer (<NUM>) is welded to an outer peripheral surface of the welding unit (<NUM>);
wherein the welding unit (<NUM>) comprises two half-ring parts (<NUM>), and each of the half-ring parts (<NUM>) comprises, along an axial direction thereof, a welding fixing area (<NUM>), and two smooth transition areas (<NUM>) respectively connected to two ends of the welding fixing area (<NUM>); and
wherein a thickness of the welding fixing area (<NUM>) is greater than thicknesses of the smooth transition areas (<NUM>), and the first end of the second armor layer (<NUM>) is welded to an outer peripheral surface of the welding fixing area (<NUM>).