Stress-whitening-preventing colored PVC (polyvinyl chloride) electrical sheath tube

Abstract

The utility model relates to the technical field of electrical bushings, and discloses a stress whitening prevention colored PVC electrical sheath tube, which comprises an inner layer, a middle buffer layer and an outer layer which are coaxially arranged and are integrally extruded and molded. The inner layer is of a smooth cylinder structure, the outer layer is a closed annular protective shell, and the middle buffer layer is used for relieving stress concentration and preventing the surface from becoming white. The middle buffer layer is of a corrugated structure or a honeycomb structure and has good deformation energy absorption capacity, stress can be effectively released when the pipe is subjected to external force such as bending and compression, and the visual whitening phenomenon on the surface of the outer layer is avoided. The outer surface of the outer layer can be provided with uniformly distributed convex rib structures to guide stress diffusion, so that the use reliability of the protective sleeve is improved. The cable is simple in structure and convenient to manufacture, and the three-resistance stress whitening performance and the appearance stability of the sheath pipe can be remarkably improved.

Description

Technical Field

[0001] This utility model relates to the field of pipe technology, and more specifically to a stress-resistant, whitening colored PVC electrical conduit. Background Technology

[0002] PVC electrical conduit is a commonly used wiring protection material in building electrical installations. It boasts excellent insulation properties, corrosion resistance, and ease of installation, making it widely used in residential, commercial, and industrial electrical wiring. Especially with the increasing market demands for product appearance and aesthetics, colored PVC conduit is finding increasingly wider application in construction management and categorized wiring.

[0003] However, in existing technologies, colored PVC electrical conduit often exhibits "stress whitening" during actual use due to mechanical actions such as bending, compression, and impact. This manifests as whitening or loss of gloss in areas of stress concentration. This whitening is not caused by material aging or quality defects, but rather by microscopic changes or damage to the internal structure of the conduit under stress. This results in a visual color change, affecting the product's appearance and potentially leading to misjudgment as product damage in certain situations.

[0004] Existing sheathing pipes are mostly single-layer or homogeneous structures, which are prone to stress concentration in a certain local area after being subjected to force, resulting in irreversible structural deformation, which in turn causes the surface to turn white, affecting the quality of subsequent construction and customer satisfaction.

[0005] Therefore, there is an urgent need to provide a new type of electrical conduit with optimized structure. By introducing an intermediate layer structure with buffering and stress dispersion functions into the conduit structure, stress concentration problems can be effectively alleviated, the risk of surface whitening can be reduced, and the product's performance and market competitiveness can be improved without changing the traditional material system. Utility Model Content

[0006] This invention provides a PPR pipe with a reasonable structural hierarchy and clear synergistic effect among the layers, resistant to linear cracking. Through its composite structural design, the pipe introduces transition buffer zones and reinforcement zones between the material layers, effectively suppressing axial crack propagation and improving reliability.

[0007] To achieve the above objectives, this utility model provides the following technical solution, mainly including:

[0008] A stress-resistant, whitening colored PVC electrical conduit includes a three-layer structure consisting of an inner layer, a middle buffer layer, and an outer layer arranged coaxially, with the three layers integrally extruded.

[0009] The inner layer is a cylindrical solid structure with a smooth inner wall and uniform thickness, used to provide through holes and basic support for cable conductors;

[0010] The outer layer is a completely enclosed annular cylindrical shell, located on the outermost side, used to provide external protection and structural support for the sheath tube;

[0011] The intermediate buffer layer is disposed between the inner layer and the outer layer to absorb and mitigate stress fluctuations caused by external forces. The structure of the intermediate buffer layer is one of the following two:

[0012] (a) A corrugated structure with multiple alternating convex and concave wave surfaces along the axial or helical direction;

[0013] (b) Honeycomb structure, composed of multiple hexagonal grids, distributed in a ring or band shape.

[0014] Furthermore, the thickness of the intermediate buffer layer is 15% to 40% of the total wall thickness of the sheath tube.

[0015] Furthermore, the outer layer is provided with a plurality of evenly distributed fine ribs or reinforcing ribs in the circumferential direction.

[0016] Furthermore, the inner layer, intermediate buffer layer, and outer layer are manufactured as a single unit using a co-extrusion molding process, resulting in a strong bond between the structural layers and a continuous structure.

[0017] As can be seen from the above technical solution, compared with the prior art, the beneficial effects of this utility model are as follows:

[0018] (1) The three-layer composite structure design effectively guides and disperses the bending force, pressure and impact force from the outside, so as to extend and disperse the stress transmission path, thereby avoiding the stress concentration in a certain area of ​​the pipe.

[0019] (2) The intermediate buffer layer adopts a corrugated, honeycomb or cavity structure, which can undergo elastic deformation under external force and has a certain energy absorption capacity to prevent surface structure damage caused by plastic deformation.

[0020] (3) The outer layer is equipped with auxiliary structural reinforcing ribs to further optimize the stress distribution effect and improve the structural stability of the pipe under bending conditions. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0022] Figure 1 This is a cross-sectional view of the corrugated structure of this utility model.

[0023] Figure 2 This is a cross-sectional view of the honeycomb structure of this utility model.

[0024] 1-Inner layer, 2-Middle buffer layer, 3-Outer layer. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] Example 1

[0027] The present invention will be further described below with reference to the accompanying drawings and preferred embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0028] like Figure 1 As shown, this embodiment provides a stress-resistant whitening colored PVC electrical conduit, which includes a three-layer structure consisting of an inner layer, a middle buffer layer, and an outer layer arranged along the coaxial direction. The three-layer structure is formed in one step using a co-extrusion molding process, and the layers are firmly bonded together, resulting in a strong overall structure.

[0029] The inner layer is a cylindrical solid tube with a smooth circular cross-section and uniform thickness, used to provide stable through-hole support space for cable conductors.

[0030] The outer layer is a completely enclosed cylindrical shell located on the outermost side of the sheath tube, which provides overall strength and mechanical protection. The outer surface can be colored as needed to meet construction identification and appearance requirements.

[0031] An intermediate buffer layer is positioned between the inner and outer layers. Its structure is corrugated, with corrugations distributed along the pipe's axial direction, forming multiple sets of continuous alternating convex and concave surfaces to create an elastic deformation zone. When the sheath is subjected to bending or compressive stress during construction, the corrugated structure can deform locally, absorbing some of the stress and delaying its transmission to the outer layer, thus effectively preventing stress whitening on the outer surface. The corrugation height is controlled at approximately 20% of the total wall thickness, providing a buffering function without weakening the overall strength.

[0032] The three-layer structure design described in the above embodiments is suitable for the production of conventional electrical conduit. The outer diameter of the conduit can be 16mm-32mm, and the total wall thickness is between 1.2mm-2.2mm, making it suitable for common wire and cable laying environments.

[0033] Example 2

[0034] like Figure 2 As shown, in this embodiment, the intermediate buffer layer adopts a honeycomb structure and is located between the inner and outer layers. This honeycomb layer is composed of multiple hexagonal grid units, with the unit structure uniformly distributed in a ring shape, and is integrally formed during the extrusion process. The honeycomb structure has excellent anisotropic and uniform buffering performance; when subjected to external force, it can generate localized compression without affecting the overall geometry, thereby achieving the purpose of shock absorption, energy dissipation, and prevention of stress concentration.

[0035] During actual construction, the sheath did not show obvious whitening when subjected to repeated bending, pushing or pulling. The outer structure remained intact and the surface maintained a uniform color, proving that the structure has excellent resistance to stress whitening.

[0036] In addition, depending on the usage requirements, several fine rib structures evenly distributed in the circumferential direction can be provided on the outer surface of the outer layer to further induce and disperse stress paths, thereby improving its stability and reliability under complex stress environments.

[0037] The three-layer structure design described in the above embodiments is suitable for the production of conventional electrical conduit. The outer diameter of the conduit can be 16mm-32mm, and the total wall thickness is between 1.2mm-2.2mm, making it suitable for common wire and cable laying environments.

[0038] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. Anti-stress whitening colored PVC electrical conduit, characterized in that, It includes a three-layer structure consisting of an inner layer (1), a middle buffer layer (2), and an outer layer (3) arranged coaxially, which are integrally extruded. The inner layer (1) is a cylindrical solid structure with a smooth inner wall and uniform thickness, used to provide through holes and basic support for cable conductors; The outer layer (3) is a completely closed annular cylindrical shell located on the outermost side, used to provide external protection and structural support for the sheath tube; The intermediate buffer layer (2) is disposed between the inner layer (1) and the outer layer (3) to absorb and mitigate stress fluctuations caused by external forces. The structure of the intermediate buffer layer (2) is one of the following two: (a) A corrugated structure with multiple alternating convex and concave wave surfaces along the axial or helical direction; (b) Honeycomb structure, composed of multiple hexagonal grids, distributed in a ring or band shape.

2. The anti-stress whitening colored PVC electrical conduit according to claim 1, characterized in that, The thickness of the intermediate buffer layer (2) is 15% to 40% of the total wall thickness of the sheath.

3. The anti-stress whitening colored PVC electrical conduit according to claim 1, characterized in that, The outer layer (3) has multiple evenly distributed fine ribs or reinforcing ribs in the circumferential direction.

4. The anti-stress whitening colored PVC electrical conduit according to claim 1, characterized in that, The inner layer (1), the intermediate buffer layer (2) and the outer layer (3) are manufactured as a single unit using a co-extrusion molding process, with each structural layer firmly bonded together and the structure continuous.

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