A traction head for submarine cable tension test and its installation method

Abstract

The present invention provides a traction head for submarine cable tension testing, comprising a tension cylinder, a traction cylinder and a compression tube, wherein the traction cylinder is passed through the tension cylinder, and a thrust bearing is provided between the two; the compression tube is used for fixed connection with the conductor of the submarine cable, and is passed through the traction cylinder and detachably connected to the traction cylinder; the tension cylinder is fastened to a fastening flange, and is used to fix the armored steel wire of the submarine cable. The present invention also provides an installation method for the aforementioned traction head for submarine cable tension testing. The benefit of the present invention is that, by providing the tension cylinder, the traction cylinder and the compression tube, the part that applies force to the armored steel wire is separated from the part that applies force to the conductor, which can both transmit tension and allow relative rotation, effectively solving the problem in the prior art that the two parts cannot rotate relative to each other, and avoiding the dangerous consequences caused by the force-applying part breaking due to torsional force.

Description

Technical Field

[0001] The invention relates to equipment for submarine cable tension testing, in particular to a traction head for submarine cable tension testing and an installation method thereof. Background Art

[0002] During tension testing of submarine cables, a pulling head is required to simultaneously subject the conductor and armor wire of the submarine cable to tension. Because the armor wires, when subjected to tension, contract radially, extend longitudinally, and rotate, this causes the armor wires and conductor to be stressed asynchronously, and the components applying tension to the conductor and armor wires to rotate relative to each other.

[0003] The Chinese utility model patent, "A cable head connection device for submarine cable tension bending tests," with publication number CN212621853U, discloses a connection device comprising a wire pull plate, a conductor load-bearing pull plate, and a connecting screw, wherein the wire pull plate and the conductor load-bearing pull plate are connected by the connecting screw. This device has the following problems: 1. The conductor tension-applying portion (conductor load-bearing pull plate) and the armor wire tension-applying portion (wire pull plate) are rigidly connected by a metal rod. During the tension increase process, the armor wire tightens, causing the two force-applying portions to rotate relative to each other, and the metal rod is prone to breakage. Since the test tension is very high, generally around 300kN, once the metal rod breaks, the submarine cable will eject uncontrollably, which is extremely dangerous. 2. The armor wire must pass through the armor hole of the wire pull plate and then be covered with a metal sleeve. The metal sleeve is then welded firmly to the armor wire to achieve a fixed connection between the armor wire and the wire pull plate. Because the steel wire is very hard, this process is very time-consuming. In addition, in order to make penetration easier, it is necessary to reserve sufficient length for the armor wire, which further aggravates the relative rotation between the two force-applying parts. Summary of the Invention

[0004] In view of the above-mentioned defects, the object of the present invention is to provide a pulling head for submarine cable tension testing, which allows relative rotation between the components that apply tension to the conductor and the armored steel wire, so that the pulling head meets the requirements of the submarine cable tension test.

[0005] The present invention provides a traction head for submarine cable tension testing, comprising a tension cylinder, a traction cylinder and a compression tube. The traction cylinder is inserted into the tension cylinder, and a thrust bearing is provided between the two. The compression tube is inserted into the traction cylinder and is detachably connected to the traction cylinder for fixed connection with the conductor of the submarine cable. The tension cylinder is fastened to a fastening flange for fixing the armored steel wire of the submarine cable.

[0006] Preferably, a pull rod is provided on the traction cylinder.

[0007] Preferably, a screw is provided on the compression tube, and the screw passes through the traction tube and is detachably connected to the traction tube via a fastening nut.

[0008] The present invention also provides a method for installing the aforementioned traction head for submarine cable tension testing, comprising the following steps:

[0009] processing the first end of the submarine cable, stripping off components other than the conductor from the first end, leaving a desired length of the conductor;

[0010] Sleeve the crimping tube onto the first end of the conductor, and use a crimping pliers to compress the crimping tube to securely connect the conductor and the crimping tube;

[0011] Putting the fastening flange on the submarine cable;

[0012] bending a portion of the armored steel wires close to the first end of the submarine cable toward the second end of the submarine cable to form a bent section, so that the bent sections of all armored steel wires are evenly distributed along the circumference of the submarine cable;

[0013] Put the traction tube on the submarine cable so that the crimping tube passes through the first end of the traction tube;

[0014] First, the thrust bearing is sleeved on the second end of the traction cylinder, and then the tension cylinder is sleeved on the outer side of the thrust bearing;

[0015] clamping the bent sections of all armored steel wires between the fastening flange and the second end of the tension cylinder, and fastening the fastening flange and the second end of the tension cylinder;

[0016] Applying pre-tension to the traction drum to pre-stretch the armored steel wire;

[0017] Tightly connecting the traction tube to the compression tube;

[0018] Start the tension test.

[0019] Preferably, the length L of the bent section is greater than the axial elongation of the armored steel wire when pre-tension is applied to the traction drum.

[0020] The present invention is beneficial in that

[0021] 1. The armored steel wire is clamped by tightening the flange and tension cylinder, without the need for perforation, which can save installation time;

[0022] 2. By providing a tension cylinder, a pulling cylinder, and a crimping tube, the part applying force to the armored steel wire is separated from the part applying force to the conductor, which can both transmit tension and allow relative rotation. This effectively solves the problem of the two parts being unable to rotate relative to each other in the prior art and avoids the dangerous consequences of the force-applying part being broken due to torsion.

[0023] 3. The cylindrical structure of the tension cylinder and the traction cylinder has a larger force-bearing surface during the tension application process, and the structure is more stable;

[0024] 4. All parts except the compression tube can be recycled. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a three-dimensional diagram of the connection structure between the traction head and the submarine cable of the present invention;

[0026] Figure 2 This is a front view of the connection structure between the traction head and the submarine cable of the present invention;

[0027] Figure 3 This is a left view of the connection structure between the traction head and the submarine cable of the present invention;

[0028] Figure 4 yes Figure 3 Cross-sectional view in the AA direction.

[0029] Component number description:

[0030] 1 Submarine cables

[0031] 11 Armored steel wire

[0032] 12 conductors

[0033] 2 tension cylinder

[0034] 3 thrust bearings

[0035] 4 traction cylinder

[0036] 41 tie rod

[0037] 5. Crimp tube

[0038] 51 screws

[0039] 6 Fastening flange

[0040] 7 Fasteners

[0041] 8 Fastening nut DETAILED DESCRIPTION

[0042] The following is a further detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings. These embodiments are only used to illustrate the present invention, and are not intended to limit the present invention.

[0043] In the description of the present invention, it should be noted that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0044] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0045] Figure 2 Shown is a front view of the traction head of the present invention observed from the front. In the following description, Figure 2 The attached drawings in the figure serve as a reference for the direction. Figure 2 In the figure, the direction perpendicular to the drawing paper is the front direction, the direction perpendicular to the drawing paper is the back direction, the direction upward along the drawing paper is the upper direction, the direction downward along the drawing paper is the lower direction, the direction to the right along the drawing paper is the right direction, and the direction to the left along the drawing paper is the left direction. The axial direction of the submarine cable 1 is the left and right direction, the first end is the right end, and the second end is the left end.

[0046] like Figure 1-4 As shown in FIG, the present invention provides a traction head for submarine cable tension test, which includes a tension drum 2, a traction drum 4 and a compression tube 5. Figure 4 As shown, the traction cylinder 4 is inserted into the tension cylinder 2 and exits from the right end of the cylinder. A thrust bearing 3 is located in the annular cavity between the traction cylinder 4 and the tension cylinder 2. The thrust bearing 3 allows relative rotation between the traction cylinder 4 and the tension cylinder 2 while limiting axial and radial displacement of the traction cylinder 4. A U-shaped pull rod 41 is located at the right end of the traction cylinder 4 and is used to apply tension to the traction cylinder 4.

[0047] The crimping tube 5 is used to securely connect to the conductor 12 in the submarine cable 1. Its main body is located within the traction drum 4, with its right end protruding from the right end of the traction drum 4 and detachably connected to the traction drum 4. Specifically, a screw 51 is provided at the right end of the crimping tube 5. The screw 51 protrudes from the right end of the traction drum 4 and is secured to the traction drum 4 via a fastening nut 8. The diameter of the fastening nut 8 is larger than the diameter of the opening at the right end of the traction drum 4, thereby ensuring a secure connection between the screw 51 and the traction drum 4.

[0048] The left end of the tension cylinder 2 is fastened to the fastening flange 6 via a fastener 7, which is used to fix the armored steel wire 11 in the submarine cable 1. The fastener 7 is preferably a screw and a nut.

[0049] like Figure 1-4 As shown, the present invention also provides a method for installing the aforementioned traction head for submarine cable tension testing, comprising the following steps:

[0050] The right end of the submarine cable 1 is processed by stripping off all components except the conductor 12 , leaving the conductor 12 of the required length.

[0051] The crimping tube 5 is placed on the right end of the conductor 12 and the crimping tube 5 is compressed using a crimping pliers to securely connect the conductor 12 and the crimping tube 5 .

[0052] The fastening flange 6 is put on the submarine cable 1.

[0053] The portion of the armored steel wire 11 close to the right end of the submarine cable 1 is bent toward the left end of the submarine cable 1 to form a bent section with a length of L, so that the bent sections of all the armored steel wires 11 are evenly distributed along the circumference of the submarine cable 1, ensuring that the subsequent tension on the armored steel wires 11 is uniform.

[0054] The traction cylinder 4 is put on the submarine cable 1 so that the screw 51 of the crimping tube 5 is passed through the right end of the traction cylinder 4 .

[0055] First, sleeve the thrust bearing 3 onto the left end of the traction cylinder 4, and then sleeve the tension cylinder 2 onto the outside of the thrust bearing 3 so that the thrust bearing 3 is located between the traction cylinder 4 and the tension cylinder 2.

[0056] The bent section of the armored steel wire 11 is clamped between the fastening flange 6 and the left end of the tension cylinder 2 , and the fastening flange 6 and the left end of the tension cylinder 2 are fastened and connected using a fastener 7 .

[0057] Pre-tension is applied to the pull rod 41 of the pulling drum 4 to pre-stretch the armor wire 11 until the armor wire 11 no longer significantly stretches. Applying pre-tension can eliminate the elongation of the armor wire 11 before the tension test, avoiding the problem of asynchronous force applied to the armor wire 11 and the conductor 12 due to the extension of the armor wire 11 during the tension test.

[0058] Screw the fastening nut 8 onto the screw 51 until the screw 51 abuts against the right end of the traction cylinder 4, completing the fastening connection between the crimping tube 5 and the traction cylinder 4.

[0059] Start the tension test.

[0060] In the above installation method, as pretension is applied, the armor wire 11 stretches axially, causing the fastening flange 6, tension drum 2, and traction drum 4 to move rightward. This poses a risk of the fastening flange 6 and tension drum 2 separating from the submarine cable 1. Therefore, in one embodiment of the present invention, the length L of the bent section of the armor wire 11 is greater than the axial extension of the armor wire 11 when pretension is applied to the traction drum 4. In other words, the length of the submarine cable 1 within the tension drum 2, stripped of the armor wire 11, is greater than the axial extension of the armor wire 11 when pretension is applied. This ensures that the tension test proceeds properly.

[0061] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A traction head for submarine cable tension testing, characterized in that: It includes a tension tube, a traction tube and a compression tube, wherein the traction tube is inserted into the tension tube, and a thrust bearing is provided between the two. The crimping tube is passed through the traction drum and is detachably connected to the traction drum, and is used for fixed connection with the conductor of the submarine cable; The tension cylinder is tightly connected to the fastening flange and is used to fix the armored steel wire of the submarine cable.

2. The traction head according to claim 1, characterized in that: A pull rod is provided on the traction cylinder.

3. The traction head according to claim 1, characterized in that: The compression tube is provided with a screw, which passes through the traction tube and is detachably connected to the traction tube via a fastening nut.

4. A method for installing a traction head for submarine cable tension testing according to claim 1, characterized in that: The following steps are involved: processing the first end of the submarine cable, stripping off components other than the conductor from the first end, leaving a desired length of the conductor; Sleeve the crimping tube onto the first end of the conductor, and use a crimping pliers to compress the crimping tube to securely connect the conductor and the crimping tube; Putting the fastening flange on the submarine cable; bending a portion of the armored steel wires close to the first end of the submarine cable toward the second end of the submarine cable to form a bent section, so that the bent sections of all armored steel wires are evenly distributed along the circumference of the submarine cable; Put the traction tube on the submarine cable so that the crimping tube passes through the first end of the traction tube; First, the thrust bearing is sleeved on the second end of the traction cylinder, and then the tension cylinder is sleeved on the outer side of the thrust bearing; clamping the bent sections of all armored steel wires between the fastening flange and the second end of the tension cylinder, and fastening the fastening flange and the second end of the tension cylinder; Applying pre-tension to the traction drum to pre-stretch the armored steel wire; Tightly connecting the traction tube to the compression tube; Start the tension test.

5. The installation method according to claim 4, characterized in that: The length L of the bending section is greater than the axial elongation of the armored steel wire when pre-tension is applied to the traction drum.

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