Cable insulation layer thermal extension automatic detection device and test method thereof

Abstract

The invention discloses a cable insulation layer thermal extension automatic detection device and a test method thereof, the detection device comprises a drying oven and a sample mounting rack, a suspension position is arranged on the sample mounting rack, a cable insulation layer sample is clamped by a clamping piece and suspended at the suspension position, the clamping piece at the lower end is connected with a weight, and the weight is connected with the drying oven. A transparent plate is arranged on the front face of the drying oven, a camera is arranged on the outer side of the transparent plate, a timer and an air circulation device are arranged on the drying oven, lifting mechanisms are arranged in the drying oven and correspond to the hanging positions respectively, electric scissors are arranged on the lifting mechanisms respectively, and displacement sensors are arranged below the electric scissors. And an induction sheet is arranged on the side surface of the clamping piece at the lower end. According to the test method, the test is automatically carried out step by step through timing of the timer, shearing of the electric scissors and the like, the oven does not need to be opened again for operation in the test process, and the test result can be photographed and recorded through the camera. The device does not completely depend on manual operation any more, so that the test efficiency is higher.

Description

Technical Field

[0001] The invention relates to the technical field of cable insulation layer thermal extension test, and in particular to a cable insulation layer thermal extension automatic detection device and a test method thereof. Background Art

[0002] The thermal extension test of the cable insulation layer is an important indicator for testing the mechanical and physical properties of the cable insulation layer. The rationality of the test process will directly affect the test results and efficiency. The test methods required in the corresponding standards are as follows:

[0003] The cable insulation layer samples are made according to the standard requirements, and the test process should be carried out in an oven. In the oven, each cable insulation layer sample should be hung and fixed, and the upper and lower ends of the cable insulation layer sample are clamped with chucks, and a heavy object is hung on the chuck at the lower end. The specific steps include:

[0004] S1, first control the oven temperature to rise, when the oven temperature rises to the set temperature (preferably within 5 minutes), keep the cable insulation layer sample in the oven for 10 minutes, then measure the standard distance and calculate the elongation;

[0005] S2, open the oven door, remove the tension on the cable insulation layer sample, that is, remove the clamp and weight at the lower end, then close the oven door again, keep the cable insulation layer sample in the oven, control the oven to heat up again, wait until the oven temperature returns to the specified temperature, and stay for the set time (usually 5 minutes);

[0006] S3. Take the cable insulation layer sample out of the oven, cool it to room temperature, and measure the distance between the marks on the cable insulation layer sample again;

[0007] S4, turn off the oven.

[0008] The above test method roughly realizes the test of thermal extension of the cable insulation layer, but the above test method basically requires manual waiting at the side throughout the whole process, relies on manual operation, and the operation is cumbersome. When there are many samples to be tested, a lot of manpower is required. Moreover, in step S3, the cable insulation layer sample is taken out of the oven, and it takes a long time to wait outside for the cable insulation layer sample to cool to room temperature, and a table needs to be reserved for the cable insulation layer sample to be placed, which is not only inefficient, but also takes up space.

[0009] In addition, in the above test method, directly using an ordinary chuck to clamp the cable insulation layer sample will cause the force area of ​​the cable insulation layer sample at the clamp to be too concentrated. Generally, the force area is only 1mm, resulting in excessive pressure per unit area. During the heating process, if the clamping force of the chuck is too large, it is easy to cause the cable insulation layer sample to break at the clamp, resulting in test failure. Summary of the invention

[0010] The first object of the present invention is to provide an automatic detection device for thermal extension of cable insulation layer.

[0011] The second object of the present invention is to provide a test method using the automatic detection device for thermal extension of cable insulation layer.

[0012] The present invention can more efficiently perform a thermal extension test on a cable insulation layer.

[0013] The first object of the present invention is achieved by the following technical solutions:

[0014] A cable insulation layer thermal extension automatic detection device, characterized in that it includes an oven and a sample mounting frame placed in the oven, at least one hanging position is provided on the sample mounting frame, during the test, the upper and lower ends of the cable insulation layer sample are clamped by clamping members and hung at the hanging positions, wherein the clamping member at the lower end is connected to a weight of a set weight, a transparent plate is provided on the front of the oven, and cameras for taking pictures of the cable insulation layer sample are provided on the outer side of the transparent plate corresponding to each hanging position, a timer and an air circulation device for circulating and exchanging internal and external air are provided on the oven, a lifting mechanism is provided in the oven corresponding to each hanging position, and electric scissors for cutting the cable insulation layer sample are provided on each lifting mechanism, a displacement sensor is provided below the electric scissors, and a sensing sheet used in conjunction with the displacement sensor is provided on the side of the clamping member at the lower end.

[0015] A further technical solution of the present invention is that a protective pad for receiving the fallen clamping parts and weights is provided under the sample mounting frame.

[0016] A further technical solution of the present invention is that a steel mesh is provided on the protective pad.

[0017] A further technical solution of the present invention is: the clamping member includes a fixed clamping plate, a movable clamping plate and a connecting bolt, the fixed clamping plate and the movable clamping plate are arranged opposite to each other, the fixed clamping plate and the movable clamping plate are used to clamp the cable insulation layer sample, and the fixed clamping plate and the movable clamping plate are connected by the connecting bolt.

[0018] A further technical solution of the present invention is that the surfaces of the fixed clamping plate and the movable clamping plate for clamping the cable insulation layer sample are provided with tooth grooves.

[0019] A further technical solution of the present invention is that a lighting source is arranged in the oven.

[0020] A further technical solution of the present invention is that a crossbeam is arranged on the upper side of the sample mounting frame, and a clamping piece at the upper end is fixed on the crossbeam.

[0021] A further technical solution of the present invention is that a display for displaying the temperature inside the oven and the countdown time of the timer is provided on the oven.

[0022] The second object of the present invention is achieved by the following technical solutions:

[0023] A test method for testing using the automatic detection device for thermal extension of cable insulation layer is characterized by comprising the following steps:

[0024] S1, mark the upper and lower ends of the cable insulation layer sample respectively;

[0025] S2, clamp the cable insulation layer sample by a clamping piece and hang it at the hanging position of the sample mounting frame, and connect a weight of a set weight to the clamping piece at the lower end;

[0026] S3, starting the oven, and after the oven temperature reaches a first set temperature, placing the sample mounting frame into a corresponding position of the oven;

[0027] S4, start the camera to take a photo, obtain the distance between the marking lines at both ends according to the position of the marking lines on the photo, and record it as the initial length;

[0028] S5, the oven continues to heat up to the second set temperature, triggering the timer, and triggering the camera to take a photo when the first set time is reached. The distance between the marking lines at both ends is obtained by the position of the marking lines on the photo and recorded as the stretching length;

[0029] S6, start the lifting mechanism to drive the electric scissors to descend. When the displacement sensor detects that the distance reaches the set distance, the lifting stops and the electric scissors are started to cut the cable insulation layer sample. The cutting position is lower than the marking line at the lower end.

[0030] S7, after the electric scissors complete cutting, the timer is triggered, and the oven is maintained at the second set temperature. When the timer reaches the second set time, the air circulation device is triggered, and the oven stops heating. When the temperature in the oven drops to room temperature, the camera is triggered to take a photo. The distance between the marking lines at both ends is obtained through the position of the marking lines on the photo and recorded as the length after cooling.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The present invention can achieve greater automation in the process of conducting a thermal extension test on the cable insulation layer. Through the timing of a timer, the cutting of electric scissors, etc., the test can be automatically carried out step by step. During the test, after the cable insulation layer sample is placed in the oven, there is no need to open the oven again for operation, which can avoid burns. The test results can be recorded by taking photos through a camera, without the need for manual recording, and no longer completely relying on manual operation, making the test more efficient.

[0033] 2. The present invention further achieves clamping of the cable insulation layer sample by means of the fixed clamping plate and the movable clamping plate of the clamping member. After clamping, the contact surface with the cable insulation layer sample is larger, thereby avoiding excessive concentration of force on the cable insulation layer sample and better avoiding breakage of the cable insulation layer sample during heating. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a schematic structural diagram of an oven according to an embodiment of the present invention;

[0035] Figure 2 is a schematic structural diagram of a sample mounting frame according to an embodiment of the present invention;

[0036] Figure 3 is a schematic side structural diagram of a clamping member according to an embodiment of the present invention;

[0037] Figure 4 It is a schematic diagram of the assembly position of part of the structure of an embodiment of the present invention.

[0038] Meaning of reference numerals in the figure:

[0039] 1- oven; 2- display; 3- control knob; 4- camera; 5- transparent plate; 6- LED lamp; 7- sample mounting frame; 8- clamping piece; 8.1- fixed splint; 8.2- movable splint; 8.3- connecting bolt; 8.4- tooth groove; 9- cable insulation layer sample; 10- weight; 11- marking line; 12- support foot; 13- crossbeam; 14- protective pad; 15- electric telescopic rod; 16- electric scissors; 17- displacement sensor; 18- induction sheet; 19- scissor mouth. DETAILED DESCRIPTION

[0040] The present invention is further described below in conjunction with embodiments.

[0041] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and 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 orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0042] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0043] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0044] Example:

[0045] like Figures 1 to 4 The figure shows the automatic detection device for thermal extension of cable insulation layer of this embodiment, which comprises an oven 1 and a sample mounting frame 7 placed in the oven 1 .

[0046] The sample mounting frame 7 of this embodiment includes legs 12 arranged on both sides, a crossbeam 13 fixed to the upper ends of the legs 12, and a protective pad 14 arranged at the bottom and located between the two legs 12. The sample mounting frame 7 is detachably mounted in the oven 1, and a groove can be provided at the inner bottom of the oven 1 to limit the position of the sample mounting frame 7. When the cable insulation layer sample is suspended, the sample mounting frame 7 can be taken out or carried out in the oven 1.

[0047] Four hanging positions are reserved between the two legs 12 of the sample mounting frame 7, and the hanging positions are used to hang the cable insulation layer samples 9. In this embodiment, four cable insulation layer samples 9 can be hung on the sample mounting frame 7, and the four cable insulation layer samples 9 can be tested at the same time.

[0048] The specific hanging method of the cable insulation layer sample 9 is as follows: during the test, the upper and lower ends of the cable insulation layer sample 9 are clamped by clamping members 8 respectively, wherein the clamping member 8 at the upper end is connected to the crossbeam 13, and can be connected by conventional structures such as hooks, spring clips, bolts, etc. The clamping member 8 at the lower end is connected to a weight 10 of a set weight, and a conventional hook can be set on the clamping member 8 at the lower end, and then the weight 10 is hung on the hook.

[0049] like Figure 3 As shown, the clamping member 8 of this embodiment includes a fixed clamping plate 8.1, a movable clamping plate 8.2 and a connecting bolt 8.3. The fixed clamping plate 8.1 and the movable clamping plate 8.2 are arranged opposite to each other. The fixed clamping plate 8.1 and the movable clamping plate 8.2 are used to clamp the cable insulation layer sample 9. The fixed clamping plate 8.1 is provided with a threaded hole, and the movable clamping plate 8.2 is provided with a through hole. The connecting bolt 8.3 passes through the through hole and is threadedly connected with the threaded hole, so that the fixed clamping plate 8.1 and the movable clamping plate 8.2 are connected by the connecting bolt. The surface of the fixed clamping plate and the movable clamping plate for clamping the cable insulation layer sample is provided with a tooth groove 8.4. Among them, the fixed clamping plate 8.1 of the clamping member 8 at the upper end is connected to the crossbeam 13, and the weight 10 is connected to the fixed clamping plate 8.1 of the clamping member 8 at the lower end.

[0050] When the fixed clamping plate 8.1 and the movable clamping plate 8.2 clamp the cable insulation layer sample 9, the contact area with the cable insulation layer sample 9 will be larger, thereby avoiding excessive concentration of force on the cable insulation layer sample 9 and better avoiding the cable insulation layer sample 9 from breaking during the heating process.

[0051] Among them, a steel mesh is provided on the protective pad 14 to receive the dropped clamping piece 8 and weight 10. During the test process, one of the steps is to remove the tension on the cable insulation layer sample 9, that is, the lower end of the cable insulation layer sample 9 is cut off by the electric scissors 16 so that the clamping piece 8 and weight 10 at the lower end are separated from the main body of the cable insulation layer sample 9. At this time, the clamping piece 8 and weight 10 at the lower end will fall directly onto the protective pad 14, so as not to damage the oven.

[0052] The oven 1 includes a box body and an oven door at the front. Of course, a heating device and a temperature controller are provided in the oven 1 to control the heating and temperature in the oven. In this embodiment, a transparent plate 5 is provided on the front of the oven 1. A camera 4 for taking a picture of the cable insulation layer sample 9 is provided on the outer side of the transparent plate 5 corresponding to each hanging position. In this embodiment, four cameras 4 are provided.

[0053] The oven 1 of this embodiment is also provided with a timer and an air circulation device for circulating and exchanging the air inside and outside. The timer is used to count down the test process, and the air circulation device is used to circulate and exchange the air inside and outside the oven 1. The air circulation device is a conventional device for air circulation, which drives the air flow through a fan.

[0054] A lifting mechanism is provided in the oven 1 corresponding to each hanging position. In this embodiment, four lifting mechanisms are provided. The lifting mechanisms are specifically conventional electric telescopic rods 15 installed vertically downward. An electric scissors 16 are provided at the lower end of each electric telescopic rod 15. The electric scissors 16 are driven to rise and fall by the electric telescopic rod 15. The electric scissors 16 are used to cut the lower end of the cable insulation layer sample 9. Figure 4 As shown, when the cable insulation layer sample 9 is suspended on the sample mounting frame 7 and installed in the oven 1, the cable insulation layer sample 9 will be located at the scissor opening 19 of the electric scissors 16, and the electric scissors 16 are located above the clamping member 8 at the lower end. The electric scissors 16 adopts a conventional electric-driven scissor structure, and the internal motor drives the scissors blades to open and close to achieve shearing.

[0055] In this embodiment, a displacement sensor 17 is provided below the electric scissors 16, and a sensing sheet 18 is provided on the side of the clamping piece 8 at the lower end. The sensing sheet 18 is located directly below the displacement sensor 17 and is used in conjunction with the displacement sensor 17. Therefore, the distance between the electric scissors 16 and the clamping piece 8 at the lower end can be obtained through the displacement sensor 17, and further the shearing of the lower end of the cable insulation layer sample 9 can be achieved.

[0056] An illumination light source is also provided in the oven 1 , which may be an LED lamp 6 , for illuminating the interior of the oven during the test, so that the camera 4 can clearly capture the cable insulation layer sample and the operator can observe the situation in the oven 1 .

[0057] In addition, a display 2 for displaying the temperature in the oven 1 and the countdown time of the timer, and a control knob 3 for operating the temperature setting are also provided on the oven 1. In order to better obtain and record data, a computer and a printer are also provided, and the oven 1, the camera 4, the displacement sensor 17, the lifting mechanism, the timer, etc. can communicate with the computer to realize control and data transmission. The printer can be used to print the test data.

[0058] The test method for testing using the above-mentioned cable insulation layer thermal extension automatic detection device includes the following steps:

[0059] S1, marking the upper and lower ends of the cable insulation layer sample 9 with marking lines 11 respectively. The marking line 11 can be a circle formed by coating the cable insulation layer sample with a set color of paint. The marking line 11 is used as a mark for calculating the distance. The initial distance between the marking lines 11 at the upper and lower ends is set according to the requirements;

[0060] S2, the cable insulation layer sample 9 is clamped by the clamping member 8 and hung at the hanging position of the sample mounting frame 7, the clamping member 8 does not cover the marking line 11, that is, the marking line 11 needs to be kept exposed, and a weight 10 of a set weight is connected to the clamping member 8 at the lower end;

[0061] S3, first start the oven 1, the oven 1 is heated, and when the temperature inside the oven 1 reaches the first set temperature, the alarm on the oven 1 is triggered to sound an alarm, which can be a sound or light alarm, and then the operator opens the oven door and places the sample mounting rack 7 into the corresponding position of the oven 1;

[0062] S4, close the oven door, start the camera 4 to take a photo, and the computer obtains the distance between the marking lines 11 at both ends through the position of the marking lines 11 on the photo, and records it as the initial length; this embodiment can simultaneously test four cable insulation layer samples 9, so the initial lengths of the four cable insulation layer samples 9 are marked as A1, B1, C1, and D1 respectively;

[0063] S5, control the oven 1 to continue heating up until it reaches the second set temperature (this heating process is preferably completed within 5 minutes). During this process, the cable insulation layer sample 9 will be heated and stretched under the action of the weight. When the second set temperature is reached, the timer will be triggered. When the timer reaches the first set time, the camera 4 will be triggered to take a photo again (the first set time is 10 minutes). The computer obtains the distance between the marking lines at both ends again through the position of the marking line 11 on the photo, and records it as the stretched length. The stretched lengths of the four cable insulation layer samples 9 are marked as A2, B2, C2, and D2 respectively.

[0064] S6, start the lifting mechanism to drive the electric scissors 16 to descend. When the displacement sensor 17 detects that the distance reaches the set distance, the lifting stops. At this time, the scissor mouth 19 of the electric scissors 16 is about 5mm away from the clamping piece at the lower end. The electric scissors 16 are started to cut the cable insulation layer sample 9. The cutting position is lower than the marking line 11 at the lower end. After the lower end of the cable insulation layer sample 9 is cut off, the clamping piece 8 and the weight 10 at the lower end will be separated from the body of the cable insulation layer sample 9 and fall onto the protective pad 14. There will be no downward pulling force on the cable insulation layer sample 9.

[0065] S7, the electric scissors 16 trigger the timer after completing the shearing, and the oven 1 is kept at the second set temperature. When the timer reaches the second set time (the second set time is 5 minutes), the air circulation device is triggered, the oven 1 stops heating, and the air circulation device starts to circulate the air inside and outside the oven 1. After the set time is run, when the temperature inside the oven 1 basically drops to room temperature, the camera 4 is triggered to take pictures again. The distance between the marking lines 11 at both ends is obtained again through the position of the marking lines 11 on the photo, and recorded as the length after cooling. The lengths of the four cable insulation layer samples 9 after cooling are marked as A3, B3, C3, and D3 respectively. So far, the automatic detection device of this embodiment has completed the test of the four cable insulation layer samples 9 and recorded the corresponding test data.

[0066] Finally, the calculation process for the elongation of the cable insulation layer sample 9 is: the difference between the stretched length and the initial length is divided by the initial length. Taking the first cable insulation layer sample as an example, the elongation of the first cable insulation layer sample is equal to (A2-A1) / A1.

[0067] The calculation process of the elongation after cooling of the cable insulation layer sample is: the difference between the length after cooling and the initial length is divided by the initial length. Taking the first cable insulation layer sample as an example, the elongation after cooling of the first cable insulation layer sample is equal to (A3-A1) / A1.

[0068] The above embodiments of the present invention are not intended to limit the protection scope of the present invention, and the implementation modes of the present invention are not limited thereto. All other modifications, replacements or changes made to the above structures of the present invention based on the above contents of the present invention, in accordance with common technical knowledge and customary means in the art, without departing from the above basic technical ideas of the present invention, should fall within the protection scope of the present invention.

Claims

1. An automatic detection device for thermal extension of cable insulation layer, characterized by: The invention comprises an oven and a sample mounting frame placed in the oven, wherein at least one hanging position is arranged on the sample mounting frame, and during the test, the upper and lower ends of the cable insulation layer sample are respectively clamped by clamping members and hung at the hanging positions, wherein the clamping member at the lower end is connected with a weight of a set weight, a transparent plate is arranged on the front of the oven, and cameras for taking pictures of the cable insulation layer sample are respectively arranged on the outer side of the transparent plate corresponding to each of the hanging positions, a timer and an air circulation device for circulating and exchanging the internal air with the external air are arranged on the oven, a lifting mechanism is respectively arranged in the oven corresponding to each of the hanging positions, and an electric scissors for cutting the cable insulation layer sample are respectively arranged on each of the lifting mechanisms, a displacement sensor is arranged below the electric scissors, and a sensing sheet used in conjunction with the displacement sensor is arranged on the side of the clamping member at the lower end.

2. The automatic detection device for thermal extension of cable insulation layer according to claim 1 is characterized in that: A protective pad for receiving the clamping member and the weight that fall off is provided under the sample mounting frame.

3. The automatic detection device for thermal extension of cable insulation layer according to claim 2 is characterized in that: A steel mesh is arranged on the protective pad.

4. The automatic detection device for thermal extension of cable insulation layer according to claim 1 is characterized in that: The clamping member includes a fixed clamping plate, a movable clamping plate and a connecting bolt. The fixed clamping plate and the movable clamping plate are arranged opposite to each other. The fixed clamping plate and the movable clamping plate are used to clamp the cable insulation layer sample. The fixed clamping plate and the movable clamping plate are connected by the connecting bolt.

5. The automatic detection device for thermal extension of cable insulation layer according to claim 4 is characterized in that: The surfaces of the fixed clamping plate and the movable clamping plate for clamping the cable insulation layer sample are provided with teeth and grooves.

6. The automatic detection device for thermal extension of cable insulation layer according to claim 1 is characterized by: An illumination light source is arranged in the oven.

7. The automatic detection device for thermal extension of cable insulation layer according to claim 1 is characterized in that: A crossbeam is arranged on the upper side of the sample mounting frame, and the clamping member at the upper end is fixed on the crossbeam.

8. The automatic detection device for thermal extension of cable insulation layer according to claim 1 is characterized by: The oven is provided with a display for displaying the temperature inside the oven and the countdown time of the timer.

9. A test method using the cable insulation layer thermal extension automatic detection device according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1, mark the upper and lower ends of the cable insulation layer sample respectively; S2, clamping the cable insulation layer sample by the clamping member and hanging it at the hanging position of the sample mounting frame, and connecting a weight of a set weight to the clamping member at the lower end; S3, starting the oven, and after the oven temperature reaches a first set temperature, placing the sample mounting rack into a corresponding position of the oven; S4, start the camera to take a photo, obtain the distance between the marking lines at both ends according to the position of the marking lines on the photo, and record it as the initial length; S5, the oven continues to heat up to the second set temperature, the timer is triggered, and when the first set time is reached, the camera is triggered to take a photo, and the distance between the marking lines at both ends is obtained by the position of the marking lines on the photo, and recorded as the stretching length; S6, starting the lifting mechanism to drive the electric scissors to descend, and when the displacement sensor detects that the distance reaches the set distance, the lifting is stopped, and the electric scissors are started to cut the cable insulation layer sample, and the cutting position is lower than the marking line at the lower end; S7, after the electric scissors complete cutting, the timer is triggered, and the oven is maintained at the second set temperature. When the timer reaches the second set time, the air circulation device is triggered, and the oven stops heating. When the temperature in the oven drops to room temperature, the camera is triggered to take a photo, and the distance between the mark lines at both ends is obtained through the position of the mark lines on the photo, which is recorded as the length after cooling.

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