Wire core end sealing device for warm water crosslinking and sealing method

Abstract

The invention provides a wire core end sealing device for warm water crosslinking and a sealing method. The sealing device comprises a body made of a heat-resistant, moisture-resistant and corrosion-resistant rigid material, a threaded blind hole is formed in one surface of the body, the threaded blind hole is a halfpace hole, and the hole diameter of the threaded blind hole is gradually reduced from the surface of the body to the interior of the body, so that an inclined internal thread is formed in the body. The sealing method comprises the following steps: sleeving the body on the wire core end through the threaded blind hole; and rotating the body to enable the inclined internal threads to break the insulating layer at the end of the wire core, forming passively generated threads on the surface of the insulating layer, and continuously rotating the body until the threads of the insulating layer are tightly engaged with the inclined internal threads. The cable core sealing device is suitable for sealing cable core ends with different outer diameters, and the problems that traditional gluing or heat shrink tube sealing is prone to aging and failure in the warm water crosslinking process, and the sealing effect is not lasting are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of cable manufacturing, and particularly relates to a wire core end sealing device and a sealing method for warm water crosslinking. Background Art

[0002] In the field of power cable manufacturing, the warm water crosslinking process of stranded wire cores is a widely used technology, and its main purpose is to improve the electrical performance and mechanical strength of the cable through crosslinking reactions. This process conducts crosslinking reactions in a high-temperature water environment, enabling the insulating material to form a three-dimensional network structure, thereby significantly improving the heat resistance, chemical resistance, and mechanical strength of the cable.

[0003] During the manufacturing process of warm water crosslinked insulated cables, the sealing of the wire core end is a crucial link to ensure the cable's performance and safety. Moisture intrusion is likely to occur at the wire core end, resulting in damage to the insulating layer, and further leading to electrical failures and even safety hazards. Currently, traditional sealing methods mainly use a head cap plus insulating tape wrapping or heat shrinkable tube to block the end, which is difficult to meet the requirements of the warm water crosslinking process for long-term stable sealing performance. Specifically, when manufacturing warm water crosslinked insulated cables, the wire core needs to be immersed in water at 85°C - 95°C for 4 - 8 hours, or even longer. The adhesive of the insulating tape has a significantly reduced adhesion under high temperature and high humidity conditions (for example, the viscosity loss rate of acrylic tape can reach more than 50% above 80°C), and the sealing interface is prone to peeling, making it difficult to avoid moisture infiltration for a long time. Heat shrinkable tubes are usually made of materials such as polyethylene and polyvinyl chloride. Although they can fit the wire core after shrinking, the materials have a low elastic modulus and are difficult to maintain a stable pressing force. They are also prone to aging and failure when exposed to high temperature and high humidity environments for a long time. Especially during the warm water crosslinking process, due to the influence of temperature fluctuations and water pressure changes, the sealing material is more likely to age and deform, making it difficult to long-term and stably avoid the risk of moisture infiltration.

[0004] Therefore, developing a head end sealing technology that can maintain a stable sealing effect in a high temperature and high humidity environment and adapt to temperature and water pressure changes has become an urgent technical problem in this field. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide a wire core end sealing device and a sealing method for warm water crosslinking, which can solve the problems of easy aging of the sealing material at the wire core end and non-durable sealing effect in the prior art.

[0006] To achieve the above and other objects, the present invention is realized by including the following technical solutions: As a first aspect, the present invention provides a sealing device for the end of a core used in warm water crosslinking, which includes a body made of a rigid material with heat resistance, moisture resistance, and corrosion resistance; a threaded blind hole is provided on one surface of the body, and the threaded blind hole is a frustum-shaped hole, and the aperture of the threaded blind hole gradually decreases from the surface of the body to the inside, so as to form an inclined internal thread inside the body.

[0007] In one embodiment, the taper angle A of the inclined internal thread is 5° to 10°.

[0008] In one embodiment, the depth h of the inclined internal thread satisfies 2D ≤ h ≤ 4D, where D is the surface aperture of the threaded blind hole.

[0009] In one embodiment, the outer diameter range of the core end adapted to the sealing device is between D - 4h / 3(tanA) and D - 2h / 3(tanA).

[0010] In one embodiment, the inclined internal thread is of a pointed top type (the thread angle is about 55°), and the pitch is between 0.5 mm and 1.0 mm.

[0011] In one embodiment, a pin hole is provided on the body, and the pin hole is a through hole and is not communicated with the threaded blind hole.

[0012] In one embodiment, the pin hole is arranged perpendicular to the axis direction of the threaded blind hole.

[0013] As a second aspect, the present invention also provides a method for sealing the end of a core used in warm water crosslinking, which uses the sealing device as described in the first aspect to seal the end of the core, and specifically includes the steps:

[0014] Put the body on the end of the core through the threaded blind hole;

[0015] Rotate the body so that the inclined internal thread breaks through the insulating layer of the end of the core and forms a passively generated thread on the surface of the insulating layer. Continue to rotate the body until the thread of the insulating layer is tightly engaged with the inclined internal thread.

[0016] In one embodiment, insert a pin rod into the pin hole of the body, and rotate the pin rod to clamp the body and the end of the core.

[0017] In one embodiment, saw the end of the core flat before "putting the body on the end of the core through the threaded blind hole".

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] 1. The present invention manufactures the sealing device body by using a rigid material that is heat-resistant, moisture-resistant, and corrosion-resistant, significantly improving the stability of the material in high-temperature and high-humidity environments, overcoming the defects of traditional sealing materials being prone to aging and having a short lifespan in high-temperature and high-humidity environments, ensuring long-term reliable sealing effects; at the same time, the inclined internal thread design of the threaded blind hole forms a progressive bite when the internal thread contacts the end of the wire core. During the screwing-in process, it actively damages the insulation layer of the wire core and forms surface threads on the insulation layer. Through the thread bite, mechanical locking is achieved, realizing that the sealing device completely blocks the gap between the conductor and the insulation layer at the end of the wire core, achieving the purpose of preventing water from entering at the end of the wire core, realizing the adaptive fastening and sealing between the end of the wire core and the sealing device, adapting to different wire core outer diameters, and avoiding the problems of traditional adhesive or heat-shrinkable tube sealing being prone to aging and failure and having an unpersistent sealing effect in the warm water cross-linking process;

[0020] 2. The taper of the inclination angle of the inclined internal thread of the present invention is 5° - 10°, which can maximize the range of adaptable wire core outer diameters and avoid sealing failure caused by dimensional deviation;

[0021] 3. The collaborative design of the inclination angle, thread depth, and pitch of the present invention can ensure sufficient surface threads at the opening and ensure the biting strength and sealing strength between the surface threads and the inclined internal thread;

[0022] 4. The present invention adds a pin hole and a pin rod. By rotating the pin rod, the body can be clamped tightly with the end of the wire core. Torque can be applied through the pin rod, facilitating the clamping operation and achieving a labor-saving effect;

[0023] 5. In the sealing method provided by the present invention, passive threads are directly generated by rotating the body without pre-processing the threads at the end of the wire core;

[0024] 6. The end of the wire core is pre-sawed flat to ensure a flat sealing surface, further improving the sealing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It shows a schematic structural diagram of a wire core end sealing device for warm water cross-linking according to the present invention.

[0026] Figure 2 It shows a schematic cross-sectional view of a wire core end sealing device for warm water cross-linking according to the present invention.

[0027] Figure 3 It shows a schematic diagram of the connection between a wire core end sealing device for warm water cross-linking according to the present invention and the end of the wire core. DETAILED DESCRIPTION OF THE INVENTION

[0028] Please refer to Figures 1-3The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0029] It should be noted that the structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in the art to understand and read, and are not used to limit the conditions under which the present invention can be implemented. Therefore, they do not have technical substantial significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present invention.

[0030] Unless otherwise defined, the technical terms or scientific terms used herein should be understood in the general sense by those of ordinary skill in the field to which the present invention pertains. The "first", "second", etc. used in the present invention are used to distinguish different objects, rather than to describe a specific order, quantity, or importance. "Including" or "comprising" and other similar words mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. And the "connection" mentioned in the present invention, unless otherwise specified, includes both direct and indirect connections.

[0031] As Figures 1-3 shown, the present invention provides a sealing device for the end of the core for warm water crosslinking, which is used to block the end 200 of the insulated core of the cable to be introduced into the warm water crosslinking pool, so as to prevent moisture from invading the insulating layer at the end 200 of the core during the warm water crosslinking process. Thereby avoiding damage to the insulating layer and ensuring the production quality of warm water crosslinked cables.

[0032] The body 10 of the sealing device is made of a rigid material that is heat-resistant, moisture-resistant, and corrosion-resistant, such as 304 stainless steel, 316 stainless steel, and 321 stainless steel. Taking 304 stainless steel as an example, it can withstand temperatures above 300°C. In the high-temperature environment of 85°C - 95°C in the warm water cross-linking process, its mechanical properties and chemical stability are not affected. Moreover, stainless steel has a low coefficient of thermal expansion and is not easily deformed at high temperatures, capable of maintaining the integrity of the sealing structure; its tensile strength can reach over 520 MPa, and it can withstand water pressure fluctuations (such as the water pressure of 0.2 MPa - 0.5 MPa in the cross-linking process), avoiding seal loosening caused by pressure deformation. In addition, there are no aging mechanisms such as photo-oxidation and hydrolysis, and its service life can reach over 10 years in high-temperature and high-humidity environments without the need for frequent replacement. The body 10 can be a cylinder, or it can be in shapes such as a frustum of a cone, a cone, a cuboid, a hemisphere, etc., according to actual design needs. A threaded blind hole 20 is provided on one surface of the body 10. The threaded blind hole 20 is a stepped hole, and the aperture of the threaded blind hole 20 gradually decreases from the surface of the body 10 towards the inside, thereby forming an inclined internal thread 21 inside the body 10, ensuring that when rotating and connecting, the insulating layer of the wire core end 200 can first passively form a thread and then tightly engage with the more internal inclined internal thread 21, thus blocking the gap between the conductor and the insulating layer of the wire core end 200 and preventing water from entering the wire core end 200 during warm water cross-linking. At this time, the sealing device and the wire core end 200 also achieve rigid locking and are not easily slipped off.

[0033] Further, the surface aperture (i.e., the maximum aperture) of the threaded blind hole 20 is D (mm). In order to ensure that the inclined internal thread 21 can be adapted to the wire core end 200 with an outer diameter in a certain range, the taper angle A of the inclined internal thread 21 should be controlled within 5° - 10°, and the depth h (mm) of the inclined internal thread 21 should satisfy 2D ≤ h ≤ 4D; the outer diameter d (mm) of the adapted wire core end 200 satisfies D - 4h / 3(tanA) ≤ d ≤ D - 2h / 3(tanA), thereby ensuring that the sealing device can simultaneously adapt to wire core ends 200 with different outer diameters within a specific outer diameter range and maximizing its applicable range.

[0034] Further, in order to achieve a better thread engagement effect, the inclined internal thread 21 can be a pointed top type (the thread angle is about 55°), and the pitch is between 0.5 mm and 1.0 mm.

[0035] Further, to facilitate the operator to manually rotate the sealing device, a pin hole 30 may be formed in the body 10. The pin hole 30 is a through hole and is not communicated with the threaded blind hole 20. Specifically, the pin hole 30 may be arranged perpendicular to the axis direction of the threaded blind hole 20 or may be slightly inclined to the axis direction of the threaded blind hole 20, and this setting is more conducive to saving effort. By inserting a pin rod into the pin hole 30, the sealing device can obtain a rotational force by applying torque to the pin.

[0036] The present invention also provides a method for sealing the end of a core for warm water crosslinking, which specifically includes:

[0037] Step 1: Saw the end of the core 200 flat;

[0038] Step 2: Put the sealing device body 10 on the end of the core 200 through the threaded blind hole 20;

[0039] Step 3: Insert the pin rod into the pin hole 30 and rotate the pin rod forcefully until the end of the core 200 is clamped with the sealing device. Specifically, when the inclined internal thread 21 just touches the end of the core 200, it will break the insulating layer of the end of the core 200 and form a passively generated thread on the surface of the insulating layer. Continuing to rotate the pin rod can make the end of the core 200 move further into the sealing device until the thread on the surface of the insulating layer is tightly engaged with the inclined internal thread 21, realizing that the sealing device completely blocks the gap between the conductor and the insulating layer, achieving the purpose of preventing water from entering at the end of the core 200.

[0040] Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value. The above embodiments are only illustrative of the principles and effects of the present invention and are not used to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A wire core end sealing device for warm water cross-linking, characterized in that: It comprises a body made of a rigid material that is heat-resistant, moisture-resistant and corrosion-resistant; a threaded blind hole is opened on one surface of the body, the threaded blind hole is a step hole, and the aperture of the threaded blind hole gradually decreases from the surface of the body to the inside, thereby forming an inclined internal thread inside the body.

2. The sealing device according to claim 1, characterized in that: The angle taper A of the inclined internal thread is 5° to 10°.

3. The sealing device according to claim 2, characterized in that: The depth h of the inclined internal thread satisfies 2D≤h≤4D, where D is the surface aperture of the threaded blind hole.

4. The sealing device according to claim 3, characterized in that: The outer diameter range of the wire core end that the sealing device is adapted to is between D-4h / (3tanA) and D-2h / 3(tanA).

5. The sealing device according to claim 4, characterized in that: The inclined internal thread is a pointed-top type thread with a pitch of 0.5 mm to 1.0 mm.

6. The sealing device according to claim 1, characterized in that: The main body is provided with a pin hole, which is a through hole and is not connected with the threaded blind hole.

7. The sealing device according to claim 6, characterized in that: The pin hole is arranged perpendicular to the axial direction of the threaded blind hole.

8. A method for sealing a core end of a warm water cross-linking wire, characterized in that: The sealing device according to any one of claims 1 to 7 is used to seal the wire core end, which specifically comprises the steps of: The body is sleeved onto the wire core end through the threaded blind hole; The body is rotated to make the inclined internal thread break the insulation layer of the wire core end and form a passively generated thread on the surface of the insulation layer, and the body is continued to be rotated until the thread of the insulation layer is tightly engaged with the inclined internal thread.

9. The method for sealing the end of a wire core for warm water cross-linking according to claim 8, characterized in that: Insert the latch rod into the latch hole of the body, and rotate the latch rod to clamp the body and the wire core end.

10. The method for sealing a core end of a wire for warm water cross-linking according to claim 8, characterized in that: Before "putting the body onto the wire core end through the threaded blind hole", the wire core end is sawed flat.

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