A type of high-density polyethylene solid-wall pipe for underground metal detection

Abstract

This utility model discloses a high-density polyethylene solid-wall pipe for buried metal detection, belonging to the field of polymer pipes. It includes a pipe body, a metal insert, a gradient adhesive layer, and an outer protective layer. The metal insert is fixedly embedded in a spiral groove on the outer wall of the pipe body. The gradient adhesive layer covers the metal insert. The outer protective layer covers the gradient adhesive layer and is fused to the pipe body. The metal insert, through surface microporous structure and silane coupling agent treatment, forms a chemical bond with a maleic anhydride-grafted high-density polyethylene layer and is embedded in the spiral groove on the outer wall of the pipe body. The metal insert is made of iron-nickel alloy, with a wavy, continuously arranged structure on its outer surface. Metal / HDPE fusion bonding is achieved through a co-extrusion process, and with a detection frequency of 1-10kHz, a depth measurement accuracy of ±5% is achieved. This solves the problem of secondary construction damage caused by the difficulty in detecting metals in traditional plastic pipes.

Description

Technical Field

[0001] This utility model relates to the field of polymer pipe technology, specifically to a high-density polyethylene solid-wall pipe for underground metal detection. Background Technology

[0002] High-density polyethylene (HDPE) solid-wall pipes are mostly installed via open-cut excavation, typically at a depth of about 3 meters below the ground surface. For example, after the initial installation, some towns may require repeated renovations and expansions, necessitating the re-laying of pipes for other purposes. Due to the complexity of urban pipe networks, varying geological conditions, and non-subjective factors during construction, the burial depth and route of the pipes may not follow the predetermined design, resulting in discrepancies with the blueprints. During secondary laying, if the original blueprints are followed to avoid these deviations, the previously laid pipes are often easily damaged during actual installation.

[0003] Because the pipes are made of high-density polyethylene and buried at a depth of about 3 meters, conventional detection instruments struggle to accurately detect plastic. This leads to significant risks during secondary construction, sometimes necessitating abandoning the optimal laying route and opting for alternative installations, resulting in substantial waste. Utility Model Content

[0004] This invention provides a high-density polyethylene solid-wall pipe for underground metal detection, which can solve the problem that general detection instruments have difficulty in effectively and accurately detecting plastics, and that secondary construction can easily damage the previously buried pipe.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] A high-density polyethylene solid-wall pipe for buried metal detection includes a pipe body, a metal insert, a gradient adhesive layer, and an outer protective layer; the metal insert is fixedly embedded in a spiral groove on the outer wall of the pipe body; the gradient adhesive layer covers the metal insert; and the outer protective layer covers the gradient adhesive layer and is fused to the pipe body.

[0007] As a further embodiment of this utility model: the metal insert is an iron-nickel alloy strip with a width of 8-12mm and a thickness of 0.3-0.7mm.

[0008] As a further embodiment of this utility model: the surface of the metal insert has a continuous wave-shaped structure with wavelength L = 15-25mm and wave height H = 2-5mm.

[0009] As a further embodiment of this invention: the surface of the metal insert is provided with a honeycomb microporous structure, the micropore depth is 5-20μm, the pore diameter is 10-50μm, and the pore density is ≥500 pores / mm². 2 .

[0010] As a further embodiment of this invention: the gradient adhesive layer consists of a silane coupling agent layer and a maleic anhydride-grafted high-density polyethylene layer from the inside to the outside.

[0011] As a further embodiment of this invention: the silane coupling agent layer fills the honeycomb-like micropores on the surface of the metal insert, and the maleic anhydride-grafted high-density polyethylene layer is fused to the tube body.

[0012] As a further aspect of this utility model: the depth of the spiral groove is 1.1-1.3 times the thickness of the metal insert.

[0013] As a further embodiment of this utility model: the outer protective layer is a high-density polyethylene composite material layer with a thickness of 0.5-1.5mm.

[0014] As a further embodiment of this utility model, the spacing between adjacent metal inserts is 1 / 10 to 1 / 5 of the outer diameter of the tube.

[0015] As a further embodiment of this utility model, the ratio of the tube wall thickness to the width of the metal insert is 5:1 to 8:1.

[0016] The beneficial effects of this utility model are:

[0017] This invention comprises a high-density polyethylene (HDPE) pipe body, a metal insert, a gradient adhesive layer, and a protective layer. The metal insert, through surface microporous structure and silane coupling agent treatment, forms a chemical bond with the maleic anhydride-grafted HDPE layer and is embedded in a spiral groove on the outer wall of the pipe. The metal insert is made of an iron-nickel alloy, with a continuously wavy outer surface. Metal / HDPE melt-press bonding is achieved through a co-extrusion process, coupled with a 1-10kHz detection frequency, achieving a depth measurement accuracy of ±5%. This solves the problem of secondary construction damage caused by the difficulty in detecting traditional plastic pipes. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings.

[0019] Figure 1 This is a schematic diagram of a high-density polyethylene solid-walled tube structure for buried metal detection according to this utility model;

[0020] Figure 2 yes Figure 1 Structural sectional view;

[0021] Figure 3 yes Figure 2 Enlarged schematic diagram of the structure at point A in the middle;

[0022] Figure 4 This is a schematic diagram of the metal insert structure of this utility model.

[0023] In the figure: 1. Tube body; 101. Spiral groove; 2. Metal insert; 201. Micropore; 3. Gradient adhesive layer; 301. Silane coupling agent layer; 302. Maleic anhydride grafted high-density polyethylene layer; 4. Outer protective layer. Detailed Implementation

[0024] The technical solutions in the embodiments of this utility model are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0025] In the description of this utility model, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or a specific orientational structure and operation. Therefore, they should not be construed as limitations on this utility model.

[0026] Furthermore, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0027] Please see Figure 1-4 As shown, this utility model embodiment provides a high-density polyethylene solid wall pipe for buried metal detection, including a high-density polyethylene (HDPE) pipe body 1, a metal insert 2, a gradient adhesive layer 3, and an outer protective layer 4.

[0028] The high-density polyethylene (HDPE) pipe body 1 has a spiral groove 101 on its outer wall, the depth of which is 1.1-1.3 times the thickness of the metal insert 2. The ratio of the pipe body 1 wall thickness to the metal insert 2 width is 5:1 to 8:1. The metal insert 2 is fixedly embedded in the spiral groove 101 on the outer wall of the pipe body 1, and metal / HDPE melt-press bonding can be achieved through a co-extrusion process. The metal insert 2 can be an iron-nickel alloy strip, with a composition including 4J29 alloy (Fe 53% / Ni 47%), a magnetic permeability μr≥50000, a width of 8-12mm, and a thickness of 0.3-0.7mm. When used with a detector emitting a 1-10kHz low-frequency magnetic field, the metal insert 2 is excited to generate a strong magnetic dipole response, improving the signal-to-noise ratio by 20dB.

[0029] The frequency matching relationship between the metal insert 2 and the detection magnetic field is as follows:

[0030]

[0031] Where L is the equivalent inductance of the metal insert 2, and C is the capacitance of the detector coil.

[0032] Please see Figure 4 As shown, in this embodiment, the surface of the metal insert 2 has a continuous wavy structure with a wavelength L = 15-25 mm and a wave height H = 2-5 mm. The spacing between two adjacent metal inserts 2 is 1 / 10 to 1 / 5 of the outer diameter of the high-density polyethylene pipe 1. The wavy metal insert 2 converts axial stress into radial compressive force, reducing the risk of HDPE interface peeling and effectively resisting construction top tensile stress.

[0033] Please see Figure 3 As shown, a honeycomb-like microporous structure 201 can also be provided on the surface of the metal insert 2. The microporous structure 201 has a depth of 5-20 μm, a pore diameter of 10-50 μm, and a pore density of ≥500 pores / mm². 2 .

[0034] Please see Figure 3 As shown, a gradient adhesive layer 3 covers the metal insert 2. From the inside to the outside, the gradient adhesive layer 3 consists of a silane coupling agent layer 301 and a maleic anhydride-grafted high-density polyethylene (MAH-g-HDPE) layer. The silane coupling agent layer 301 fills the honeycomb-like micropores 201 on the surface of the metal insert 2. The maleic anhydride-grafted high-density polyethylene layer 302 is fused to the tube body 1. The silane coupling agent layer 301 is formed by KH-550 hydrolysis and condensation, with a thickness of 0.1-1 μm; the grafting rate of the maleic anhydride-grafted high-density polyethylene layer 302 is 0.8-1.5 wt%.

[0035] The mechanism of gradient adhesive layer 3: The vinyl group (-CH=CH2) in the silane coupling agent reacts with the anhydride group of MAH-g-HDPE to form a -CO-CO- covalent bond; at the same time, the polyethylene segment of MAH-g-HDPE co-crystallizes with the HDPE of pipe body 1, realizing the gradient transition of "metal-chemical bond-polymer" and solving the problem of inert interface adhesion of HDPE.

[0036] Please see Figure 3 As shown, the outer protective layer 4 covers the gradient adhesive layer 3 and is fused with the pipe body 1. The outer protective layer 4 is a high-density polyethylene composite material layer with a thickness of 0.5-1.5mm. The outer protective layer 4 completely covers the gradient adhesive layer 3 and the metal insert 2, and is fused with the HDPE pipe body 1 without any joints.

[0037] The manufacturing process of this utility model:

[0038] Step 1: Pre-treatment of metal inlay 2

[0039] Take a 4J29 alloy strip (10mm wide × 0.5mm thick) and laser-etch micropores 201.

[0040] A 200W laser with a frequency of 20kHz and a scanning speed of 5mm / s was used to generate a honeycomb micropore array 201 with a pore size of 30μm±5μm.

[0041] Immerse in KH-550 silane solution (concentration 5wt%, ethanol / water = 90 / 10), hydrolyze at 60℃ for 30 min, and cure at 120℃ to form a 0.5μm thick silane coupling agent layer 301.

[0042] Step 2: Co-extrusion molding of tube body 1

[0043] HDPE pipe body 1 extrusion: The first-stage screw plasticizes HDPE at 230℃ (melt index 0.3g / 10min);

[0044] Metal insert 2 insertion: The metal insert 2, preheated to 180°C, is precisely inserted into the spiral groove 101 through the guide die;

[0045] Interface bonding: The second-stage screw melts and coats the MAH-g-HDPE layer (grafting rate 1.2%) onto the surface of the metal insert 2 at 220℃ and a pressure of 15MPa.

[0046] This invention relates to a novel metal insert 2, which, through a surface microporous structure 201 and treatment with a silane coupling agent, forms a chemical bond with a maleic anhydride-grafted high-density polyethylene layer 302 and is embedded in the spiral groove 101 on the outer wall of the pipe body 1. The metal insert 2 is made of an iron-nickel alloy, with a wavy, continuously arranged structure on its outer surface. Metal / HDPE melt-press bonding is achieved through a co-extrusion process, and combined with a 1-10kHz detection frequency, a depth measurement accuracy of ±5% is achieved. This allows for precise and effective three-dimensional reconstruction and modeling of underground pipe networks, facilitating subsequent network monitoring and secondary trenchless construction, thus solving the problem of secondary construction damage caused by the difficulty in detecting traditional plastic pipes.

[0047] The preferred embodiments of this utility model have been described in detail above and should not be considered as limiting the scope of this utility model. All equivalent changes and improvements made within the scope of the claims of this utility model should still fall within the patent coverage of this utility model.

Claims

1. A high-density polyethylene solid-walled pipe for buried metal detection, characterized in that: It includes a tube body (1), a metal insert (2), a gradient adhesive layer (3), and an outer protective layer (4); the metal insert (2) is fixedly embedded in the spiral groove (101) on the outer wall of the tube body (1); the gradient adhesive layer (3) covers the metal insert (2); the outer protective layer (4) covers the gradient adhesive layer (3) and is fused with the tube body (1).

2. The high-density polyethylene solid-wall pipe for buried metal detection according to claim 1, characterized in that: The metal insert (2) is an iron-nickel alloy strip with a width of 8-12 mm and a thickness of 0.3-0.7 mm.

3. A high-density polyethylene solid-wall pipe for buried metal detection according to claim 2, characterized in that: The surface of the metal insert (2) has a continuous wave-shaped structure with wavelength L = 15-25 mm and wave height H = 2-5 mm.

4. A high-density polyethylene solid-wall pipe for buried metal detection according to claim 3, characterized in that: The surface of the metal insert (2) is provided with a honeycomb micropore (201) structure, the micropore (201) depth is 5-20μm, the pore diameter is 10-50μm, and the pore density is ≥500 pores / mm. 2 .

5. A high-density polyethylene solid-wall pipe for buried metal detection according to claim 4, characterized in that: The gradient adhesive layer (3) consists of a silane coupling agent layer (301) and a maleic anhydride-grafted high-density polyethylene layer (302) from the inside to the outside.

6. A high-density polyethylene solid-wall pipe for buried metal detection according to claim 5, characterized in that: The silane coupling agent layer (301) fills the honeycomb micropores (201) on the surface of the metal insert (2), and the maleic anhydride-grafted high-density polyethylene layer (302) is fused with the tube body (1).

7. A high-density polyethylene solid-wall pipe for buried metal detection according to claim 1, characterized in that: The depth of the spiral groove (101) is 1.1-1.3 times the thickness of the metal insert (2).

8. A high-density polyethylene solid-wall pipe for buried metal detection according to claim 1, characterized in that: The outer protective layer (4) is a high-density polyethylene composite material layer with a thickness of 0.5-1.5 mm.

9. A high-density polyethylene solid-wall pipe for buried metal detection according to claim 1, characterized in that: The spacing between adjacent metal inserts (2) is 1 / 10 to 1 / 5 of the outer diameter of the tube (1).

10. A high-density polyethylene solid-wall pipe for buried metal detection according to claim 1, characterized in that: The ratio of the wall thickness of the tube (1) to the width of the metal insert (2) is 5:1 to 8:1.

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