Device and method for detecting thermal shrinkage of polyethylene wires and cables

Abstract

The rapid detection device and method for the thermal shrinkage rate of the polyethylene insulating layer or sheath layer are rapid, lossless and high in precision, rapid detection of the thermal shrinkage rate of the polyethylene insulating layer or sheath layer is achieved, and the device comprises a bottom plate with holes and two side plates with holes. Electric wire and cable thermal shrinkage test samples are stored at the top of the zigzag structure, and round electric wires and cables cannot roll; 24 samples can be stored in a small-specification low-voltage wire and cable at a time for a comparison test, and 4 samples can be stored in a large-specification high-voltage cable at a time for a comparison test, so that the detection efficiency is high, and the detection result is accurate; the thermal shrinkage test temperature is 130 DEG C and is less than 2 hours, and the method is suitable for thermal shrinkage detection of polyethylene wires and cables with various voltage grades and specifications.

Description

Technical Field

[0001] The present invention relates to the technical field of wire and cable performance detection, in particular to a device and method for detecting thermal shrinkage of polyethylene wire and cable. Background Art

[0002] Polyethylene (PE) materials are prone to shrinkage when heated, resulting in a degradation of cable insulation performance. Current testing, based on GB / T 2951.13, does not specify the thermal shrinkage test apparatus and method. This leads to inconsistent test results, poor test efficiency, and an inability to meet the requirements for mass-produced thermal shrinkage testing of wires and cables. This present invention aims to address this technical bottleneck. Summary of the Invention

[0003] The technical problems to be solved by the present invention are: polyethylene materials are prone to shrinkage when heated, which reduces the insulation performance of cables; test results are inconsistent and the test efficiency is poor.

[0004] The technical solution adopted by the present invention to solve the technical problem is: a polyethylene wire and cable heat shrinkage detection device, comprising a bottom plate with holes and two side plates with holes vertically fixed on both sides of the bottom plate;

[0005] The perforated bottom plate is a rectangular stainless steel plate with an outer dimension of 400 mm in length and 256 mm in width. A rectangular inner hole is opened in the middle with an inner hole dimension of 320 mm in length and 170 mm in width, and the thickness of the stainless steel is 3 mm. The perforated side plates are rectangular stainless steel plates with an outer dimension of 400 mm in length and 156 mm in height. A rectangular inner hole is opened in the middle with an inner hole dimension of 320 mm in length and 70 mm in height, and the thickness of the stainless steel is 3 mm. The two perforated side plates are arranged in parallel with a spacing of 250 mm, and a serrated structure is provided on the top of the side plates for fixing wire and cable samples.

[0006] The number of the zigzag structures is 24, which are evenly distributed along the top of the side panels and are used to place low-voltage wire and cable samples.

[0007] The groove depth of the sawtooth structure matches the outer diameter of the cable to prevent the sample from rolling.

[0008] The inner holes of the perforated bottom plate and the perforated side plates are aligned with each other to form a through hot air channel, thereby ensuring uniform heat flow in the oven.

[0009] A method for detecting thermal shrinkage of polyethylene wires and cables, using the device according to any one of claims 1 to 4, comprising the following steps:

[0010] (a) Cut off the wire and cable sample to be tested and measure its initial length L0;

[0011] (b) Place the specimen on top of the zigzag structure, ensuring that the specimen is fixed horizontally;

[0012] (c) The entire device was placed in an oven at 130°C and heated for 2 hours;

[0013] (d) Take out the sample and cool it to room temperature, then measure the length L1 after shrinkage;

[0014] (e) Calculation of thermal shrinkage: η = [(L0-L1) / L0] x 100%.

[0015] In step (b), the number of low-voltage wire and cable samples is ≤24, and the number of high-voltage wire and cable samples is ≤4, so as to realize batch synchronous detection.

[0016] The beneficial effects of the present invention are:

[0017] (1) The thermal shrinkage detection device and method of polyethylene wires and cables of the present invention stores the thermal shrinkage test samples of the wires and cables on the top of the sawtooth structure, so that the round wires and cables will not roll, thereby improving the detection stability;

[0018] (2) The present invention can store 24 samples of small-sized low-voltage wires and cables at a time and conduct comparative tests at the same time, and can store 4 samples of large-sized high-voltage cables at a time and conduct comparative tests at the same time, with high detection efficiency, accurate detection results, and accurate test results;

[0019] (3) The present invention is composed of a bottom plate with holes and two side plates with holes, thereby realizing thermal shrinkage detection of polyethylene wires and cables. The method is applicable to thermal shrinkage detection of polyethylene wires and cables of various voltage levels and specifications. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below with reference to the accompanying drawings and examples.

[0021] Figure 1 It is a structural schematic diagram of the present invention.

[0022] Figure 2 It is the front view of the present invention.

[0023] Figure 3 It is a bottom schematic diagram of the present invention.

[0024] Figure 4 It is a schematic diagram of the method of the present invention. DETAILED DESCRIPTION

[0025] The present invention will now be described in further detail with reference to the accompanying drawings, which are simplified schematic diagrams that illustrate the basic structure of the present invention in a schematic manner.

[0026] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integral connection; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0027] Figure 1 、 Figure 2 and Figure 3 The device for detecting thermal shrinkage of polyethylene wires and cables shown in the figure comprises a bottom plate 1 with a hole and two side plates 2 with holes fixed vertically on both sides of the bottom plate;

[0028] The perforated bottom plate 1 is a rectangular stainless steel plate with an outer dimension of 400 mm in length and 256 mm in width. A rectangular inner hole is opened in the middle with an inner hole dimension of 320 mm in length and 170 mm in width, and the thickness of the stainless steel is 3 mm. The perforated side plate 2 is a rectangular stainless steel plate with an outer dimension of 400 mm in length and 156 mm in height. A rectangular inner hole is opened in the middle with an inner hole dimension of 320 mm in length and 70 mm in height, and the thickness of the stainless steel is 3 mm. The two perforated side plates 2 are arranged in parallel with a spacing of 250 mm, and a serrated structure 3 is provided on the top of the side plate for fixing the wire and cable samples.

[0029] The number of the zigzag structures 3 is 24, which are evenly distributed along the top of the side panels and are used to place low-voltage wire and cable samples.

[0030] The groove depth of the serrated structure 3 matches the outer diameter of the cable to prevent the sample from rolling.

[0031] The inner holes of the perforated bottom plate 1 and the perforated side plates 2 are aligned with each other to form a through-type hot air channel, ensuring uniform heat flow in the oven.

[0032] like Figure 4 A method for detecting thermal shrinkage of polyethylene wires and cables is provided, using the device described in any one of claims 1 to 4, comprising the following steps:

[0033] (a) Cut off the wire and cable sample to be tested and measure its initial length L0;

[0034] (b) Place the sample on top of the zigzag structure 3, ensuring that the sample is fixed horizontally;

[0035] (c) The entire device was placed in an oven at 130°C and heated for 2 hours;

[0036] (d) Take out the sample and cool it to room temperature, then measure the length L1 after shrinkage;

[0037] (e) Calculation of thermal shrinkage: η = [(L0-L1) / L0] x 100%.

[0038] In step (b), the number of low-voltage wire and cable samples is ≤24, and the number of high-voltage wire and cable samples is ≤4, so as to realize batch synchronous detection.

[0039] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A polyethylene wire and cable thermal shrinkage detection device, characterized in that: It comprises a bottom plate with holes (1) and two side plates with holes (2) fixed vertically on both sides of the bottom plate; The bottom plate with holes (1) is a rectangular stainless steel plate with an outer dimension of 400 mm in length and 256 mm in width, a rectangular inner hole is provided in the middle, the inner hole dimension is 320 mm in length and 170 mm in width, and the thickness of the stainless steel is 3 mm; the side plate with holes (2) is a rectangular stainless steel plate with an outer dimension of 400 mm in length and 156 mm in height, a rectangular inner hole is provided in the middle, the inner hole dimension is 320 mm in length and 70 mm in height, and the thickness of the stainless steel is 3 mm; the two side plates with holes (2) are arranged in parallel with a spacing of 250 mm, and a sawtooth structure (3) is provided on the top of the side plate for fixing the wire and cable samples.

2. A polyethylene wire and cable thermal shrinkage detection device according to claim 1, characterized in that: The number of the sawtooth structures (3) is 24, which are evenly distributed along the top of the side plate and are used to place low-voltage wire and cable samples.

3. The thermal shrinkage detection device for polyethylene wires and cables according to claim 1, characterized in that: The groove depth of the sawtooth structure (3) matches the outer diameter of the cable to prevent the sample from rolling.

4. The thermal shrinkage detection device for polyethylene wires and cables according to claim 1, characterized in that: The inner holes of the perforated bottom plate (1) and the perforated side plates (2) are aligned with each other to form a through-type hot air channel, thereby ensuring uniform heat flow in the oven.

5. A method for detecting thermal shrinkage of polyethylene wires and cables, using the device according to any one of claims 1 to 4, characterized in that: The following steps are involved: (a) Cut off the wire and cable sample to be tested and measure its initial length L0; (b) placing the sample on top of the sawtooth structure (3) and ensuring that the sample is fixed horizontally; (c) The entire device was placed in an oven at 130°C and heated for 2 hours; (d) Take out the sample and cool it to room temperature, then measure the length L1 after shrinkage; (e) Calculation of thermal shrinkage: η = [(L0-L1) / L0] x 100%.

6. A method for detecting thermal shrinkage of polyethylene wires and cables according to claim 5, characterized in that: In step (b), the number of low-voltage wire and cable samples is ≤24, and the number of high-voltage wire and cable samples is ≤4, so as to realize batch synchronous detection.

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