Method and device for testing internal resistance and temperature of wires and cables under flame impact

Abstract

The invention discloses a method for testing the internal temperature of wires and cables under flame impact, comprising the following steps: S1, removing the covering of the parts where the two ends of the sample are connected to the measurement system, exposing the conductor, and fixing the tested sample connected to the thermocouple on the test device as required; S2, connecting the tested sample with two special clamps of the test device, and fixing the thermocouple to the test point of the data acquisition instrument; S3, pressing the "start" button, the data acquisition instrument starts to test and record the temperature curve of the tested sample before the test; S4, completing the calibration of the temperature and height of the Bunsen burner flame, confirming that the test piece is installed in place, and the relevant parameters are consistent with the contents of the test condition table, and checking that each data acquisition device is in normal working state. This method realizes real-time testing of the temperature of different sheath layers inside the wire and cable under different flame impacts by designing the internal temperature of the wire and cable under flame impact.

Description

Technical Field

[0001] The invention belongs to the technical field of wire and cable testing, and in particular relates to a method and a device for testing the internal resistance and temperature of wires and cables under flame impact. Background Art

[0002] Since humans made and used the first wire, wire and cable fires have been constantly occurring, and the number of fire accidents accounts for a high proportion of all types of fires. With the possibility of global electrification in the future, reducing the occurrence of electrical fires and reducing the severity of the consequences of accidents have become new issues that people continue to pay attention to.

[0003] The causes of cable fires can be summarized into two categories: cable fires caused by cable faults and fires outside the cable that ignite the cable. According to data, the former type of fire accounts for about 1 / 3 of all cable fire accidents. It can be seen that the ignition of cables by external fire sources will cause the fire to spread further. At the same time, cable pipelines are laid in a hidden manner and are often connected to important places. Often, the ignition of cables in pipelines will often cause greater harm and more serious economic losses. Therefore, it is very necessary to monitor the internal temperature of wires and cables under the impact of flames, which is conducive to discovering the initial fire of wires and cables.

[0004] In addition, in addition to being an important medium for transmitting electrical energy between electrical devices, wires and cables can also be used to transmit electrical signals between devices. If a wire or cable in a certain part of the equipment fails, the transmission of electrical energy or electrical signals may be interrupted, resulting in the inability of the equipment to operate safely. Therefore, in order to ensure the normal operation of wires and cables, special attention is also paid to the electrical signal transmission capacity (i.e. resistance) of wires and cables under flame impact.

[0005] At present, although there are patents for testing the resistance of wires and cables at room temperature, there are no patents for testing the internal temperature and resistance of wires and cables under different flame impacts. Summary of the invention

[0006] Based on the technical problems existing in the background technology, the present invention proposes a method and a device for testing the internal resistance and temperature of wires and cables under flame impact.

[0007] The present invention provides a method for testing the internal temperature of wires and cables under flame impact, comprising the following steps:

[0008] S1. Remove the coverings at the connection points between the two ends of the sample and the measuring system to expose the conductors, and fix the sample connected to the thermocouple on the test device as required;

[0009] S2. Use two special fixtures of the test device to connect the test sample and fix the thermocouple to the test point of the data acquisition instrument;

[0010] S3. Press the "Start" button, and the data acquisition instrument starts to test and record the temperature curve of the sample before the test;

[0011] S4. Complete the calibration of the temperature and height of the Bunsen burner flame, confirm that the test piece is installed in place, and the relevant parameters are consistent with the contents of the test condition table. At the same time, check that each data acquisition device is in normal working condition, ignite the flame, and the data acquisition instrument starts to test and record the temperature curve of the tested sample during the test;

[0012] S5. When the test setting time is reached, the standard flame is turned off and the test is terminated;

[0013] S6. Press the "Stop" button, and the data acquisition instrument will save the temperature data of the tested sample throughout the test. After the test is completed and the burner is removed, the ablation products of the test sample are collected.

[0014] Preferably, in step S2, the thermocouples are divided into No. 1 thermocouple and No. 2 thermocouple, the sheath of the cable is cut open along the axial direction, the No. 1 thermocouple is inserted into the cable close to the refractory insulation layer, and the No. 2 thermocouple is inserted into the metal wire core along the axial direction, and the insertion depth is sufficient to enable the temperature measuring end of the thermocouple to be located in the center of the flame action area, the No. 1 thermocouple is located between the refractory insulation layer and the polyimide tape, and the No. 2 thermocouple is located in the middle of the wire core, the internal temperature field data of the cable and the curve of its change over time are obtained, and each system completes the self-inspection process before the test.

[0015] Preferably, the flame bearing time of the test is 5 minutes to 15 minutes, the flame height of the Bunsen burner is 38 mm, the lower end of the test piece is 19 mm away from the flame port, and the flame temperature ranges from 800-1000°C.

[0016] The present invention also proposes a method for testing the internal resistance of wires and cables under flame impact, comprising the following steps:

[0017] 1) Remove the coverings at the connection points between the two ends of the sample and the measuring system to expose the conductors, and fix the sample connected to the thermocouple on the test device as required;

[0018] 2) Use two special fixtures of the test device to connect the test sample, and fix the thermocouple to the test point of the data acquisition instrument;

[0019] 3) Turn on the resistance meter switch and start testing to record the resistance curve of the sample before the test;

[0020] 4) Complete the calibration of the temperature and height of the Bunsen burner flame, confirm that the test piece is installed in place, and the relevant parameters are consistent with the contents of the test condition table. At the same time, check that each data acquisition device is in normal working condition, ignite the flame, and the resistance meter starts to test and record the resistance curve of the tested sample during the test;

[0021] 5) When the test setting time is reached, the standard flame is turned off and the test is terminated;

[0022] 6) Press the "Save" button to save the resistance data of the entire test of the tested sample. After the test is completed and the burner is removed, collect the ablation products of the test sample.

[0023] The present invention also provides a device for testing the internal parts of wires and cables under flame impact, comprising:

[0024] Two relatively fixed lifting platforms;

[0025] A clamp connected to two lifting platforms, the two clamps are used to clamp and fix the wires and cables;

[0026] A Bunsen burner is arranged between two lifting platforms and is used for flame impacting electric wires and cables.

[0027] Preferably, the lifting platform includes two mounting plates arranged upper and lower, one end of the two mounting plates are rotatably connected by a rotating shaft, a micro cylinder is arranged between the other ends of the two mounting plates, the bottom of the micro cylinder is fixedly connected to the lower mounting plate, the driving end of the micro cylinder is movably connected to the upper mounting plate, and the clamp is installed at one end of the upper mounting plate.

[0028] Preferably, the clamp is a block provided with a clamping opening, a bolt is inserted into the block, nuts are threadedly connected to the upper and lower ends of the bolt, and the clamping opening is used to clamp and fix the wires and cables.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. By designing the internal temperature of wires and cables under flame impact, the real-time test of the temperature of different sheath layers inside wires and cables under different flame impacts can be achieved;

[0031] 2. By designing a method for testing the internal resistance of wires and cables under flame impact, real-time testing of the internal metal conductor resistance of wires and cables under different flame impacts can be achieved, and the changing relationship between the internal temperature field and conductor resistance of wires and cables under different flame impacts can be determined.

[0032] 3. The test device is used to measure the temperature and resistance. It has the advantages of simple structure, easy operation, and can be applied to the real-time detection of the internal temperature and resistance of various wires and cables, with accurate test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic side view of the structure of the internal device of the wire and cable under flame impact proposed by the present invention;

[0034] Figure 2This is a schematic diagram of the top view of the internal device of the wire and cable under flame impact proposed by the present invention;

[0035] Figure 3 This is a structural diagram of the thermocouple arrangement.

[0036] In the figure: 1 lifting table, 2 clamp, 3 Bunsen burner, 4 PTEF tape, 5 nickel-clad copper stranded wire, 6 polyimide tape, 7 No. 1 thermocouple, 8 fire-resistant insulation layer, 9 No. 2 thermocouple. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0038] Reference Figure 1-3 , a method for testing the internal temperature of wires and cables under flame impact, comprising the following steps:

[0039] S1. Remove the coverings at the connection points between the two ends of the sample and the measuring system to expose the conductors, and fix the sample to be tested connected to the thermocouple on the test device as required.

[0040] S2, connect the test sample with two special fixtures 2 of the test device, and fix the thermocouple to the test point of the data acquisition instrument;

[0041] The thermocouples are divided into No. 1 thermocouple 7 and No. 2 thermocouple 9. The sheath of the cable is cut open along the axial direction, and the No. 1 thermocouple 7 is inserted into the cable close to the fire-resistant insulation layer 8. The No. 2 thermocouple 9 is inserted into the metal wire core along the axial direction. The insertion depth should be able to make the temperature measuring end of the thermocouple located in the center area of ​​the flame action. The No. 1 thermocouple 7 is located between the fire-resistant insulation layer 8 and the polyimide tape 6, and the No. 2 thermocouple 9 is located in the middle of the wire core. The internal temperature field data of the cable and the curve of change over time are obtained, and each system completes the self-check process before the test;

[0042] The flame endurance time of the test is 5 minutes to 15 minutes, the flame height of Bunsen burner 3 is 38 mm, the lower end of the test piece is 19 mm away from the flame port, and the flame temperature range is 800-1000°C.

[0043] S3. Press the "Start" button, and the data acquisition instrument begins to test and record the temperature curve of the sample before the test.

[0044] S4. Complete the calibration of the temperature and height of the flame of Bunsen burner 3, confirm that the test piece is installed in place, and the relevant parameters are consistent with the contents of the test condition table. At the same time, check that each data acquisition device is in normal working condition, ignite the flame, and the data acquisition instrument starts to test and record the temperature curve of the tested sample during the test.

[0045] S5. When the test set time is reached, the standard flame is turned off and the test is terminated.

[0046] S6. Press the "Stop" button, and the data acquisition instrument will save the temperature data of the tested sample throughout the test. After the test is completed and the burner is removed, the ablation products of the test sample are collected.

[0047] Reference Figure 1-3 , a method for testing the internal temperature of wires and cables under flame impact, comprising the following steps:

[0048] 1) Remove the coverings at the connection points between the two ends of the sample and the measurement system to expose the conductors, and fix the sample to be tested connected to the thermocouple on the test device as required.

[0049] 2) Use two special fixtures 2 of the test device to connect the test sample, and fix the thermocouple to the test point of the data acquisition instrument;

[0050] The thermocouples are divided into No. 1 thermocouple 7 and No. 2 thermocouple 9. The sheath of the cable is cut open along the axial direction, and the No. 1 thermocouple 7 is inserted into the cable close to the fire-resistant insulation layer 8. The No. 2 thermocouple 9 is inserted into the metal wire core along the axial direction. The insertion depth should be able to make the temperature measuring end of the thermocouple located in the center area of ​​the flame action. The No. 1 thermocouple 7 is located between the fire-resistant insulation layer 8 and the polyimide tape 6, and the No. 2 thermocouple 9 is located in the middle of the wire core. The internal temperature field data of the cable and the curve of change over time are obtained, and each system completes the self-check process before the test;

[0051] The flame endurance time of the test is 5 minutes to 15 minutes, the flame height of Bunsen burner 3 is 38 mm, the lower end of the test piece is 19 mm away from the flame port, and the flame temperature range is 800-1000°C.

[0052] 3) Turn on the resistance meter switch and start testing to record the resistance curve of the sample before the test.

[0053] 4) Complete the calibration of the temperature and height of the Bunsen burner 3 flame, confirm that the test piece is installed in place, and the relevant parameters are consistent with the contents of the test condition table. At the same time, check that all data acquisition equipment is in normal working condition, ignite the flame, and the resistance meter starts testing and recording the resistance curve of the tested sample during the test.

[0054] 5) When the test set time is reached, the standard flame is turned off and the test is terminated.

[0055] 6) Press the "Save" button to save the resistance data of the entire test of the tested sample. After the test is completed and the burner is removed, collect the ablation products of the test sample.

[0056] refer to Figure 1-2A device for testing the internal parts of wires and cables under flame impact is suitable for testing the internal temperature and resistance of wires and cables under flame impact, comprising: two relatively fixed lifting platforms 1; clamps 2 connected to the two lifting platforms 1, the two clamps 2 are used to clamp and fix the wires and cables; a Bunsen burner 3 arranged between the two lifting platforms 1, the Bunsen burner 3 is used for flame impacting the wires and cables.

[0057] The lifting platform 1 includes two mounting plates arranged upper and lower, one end of the two mounting plates being rotatably connected by a rotating shaft, a micro cylinder being arranged between the other ends of the two mounting plates, the bottom of the micro cylinder being fixedly connected to the lower mounting plate, the driving end of the micro cylinder being movably connected to the upper mounting plate, the clamp 2 being installed at one end of the upper mounting plate, and one end of the mounting plate being rotatably connected. When the micro cylinder is started, the micro cylinder will push the upper mounting plate to rotate relative to the lower mounting plate through the driving end, thereby changing the height of the clamp 2 on the installation lifting platform 1.

[0058] The clamp 2 is a block with a clamping opening, on which a bolt is inserted, and nuts are threadedly connected at both ends of the bolt. The clamping opening is used to clamp and fix the wires and cables. By turning the nut, the size of the clamping opening is changed, thereby achieving a fixing effect on the wires and cables.

[0059] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for testing the internal temperature of wires and cables under flame impact, characterized in that: The following steps are involved: S1. Remove the coverings at the connection points between the two ends of the sample and the measuring system to expose the conductors, and fix the sample connected to the thermocouple on the test device as required; S2. Use two special fixtures of the test device to connect the test sample and fix the thermocouple to the test point of the data acquisition instrument; S3. Press the "Start" button, and the data acquisition instrument starts to test and record the temperature curve of the sample before the test; S4. Complete the calibration of the temperature and height of the Bunsen burner flame, confirm that the test piece is installed in place, and the relevant parameters are consistent with the contents of the test condition table. At the same time, check that each data acquisition device is in normal working condition, ignite the flame, and the data acquisition instrument starts to test and record the temperature curve of the tested sample during the test; S5. When the test setting time is reached, the standard flame is turned off and the test is terminated; S6. Press the "Stop" button, and the data acquisition instrument will save the temperature data of the tested sample throughout the test. After the test is completed and the burner is removed, the ablation products of the test sample are collected.

2. The method for testing the internal temperature of wires and cables under flame impact according to claim 1, characterized in that: In step S2, the thermocouples are divided into No. 1 thermocouple and No. 2 thermocouple. The sheath of the cable is cut open along the axial direction, and No. 1 thermocouple is inserted into the cable close to the refractory insulation layer. No. 2 thermocouple is inserted into the metal wire core along the axial direction. The insertion depth should be able to make the temperature measuring end of the thermocouple located in the center of the flame action area. No. 1 thermocouple is located between the refractory insulation layer and the polyimide tape, and No. 2 thermocouple is located in the middle of the wire core. The internal temperature field data of the cable and its change curve over time are obtained, and each system completes the self-inspection process before the test.

3. The method for testing the internal temperature of wires and cables under flame impact according to claim 2, characterized in that: The flame endurance time of the test is 5 minutes to 15 minutes, the flame height of the Bunsen burner is 38 mm, the lower end of the test piece is 19 mm away from the flame port, and the flame temperature range is 800-1000°C.

4. A method for testing the internal resistance of wires and cables under flame impact, characterized in that: The following steps are involved: 1) Remove the coverings at the connection points between the two ends of the sample and the measuring system to expose the conductors, and fix the sample connected to the thermocouple on the test device as required; 2) Use two special fixtures of the test device to connect the test sample, and fix the thermocouple to the test point of the data acquisition instrument; 3) Turn on the resistance meter switch and start testing to record the resistance curve of the sample before the test; 4) Complete the calibration of the temperature and height of the Bunsen burner flame, confirm that the test piece is installed in place, and the relevant parameters are consistent with the contents of the test condition table. At the same time, check that each data acquisition device is in normal working condition, ignite the flame, and the resistance meter starts to test and record the resistance curve of the tested sample during the test; 5) When the test setting time is reached, the standard flame is turned off and the test is terminated; 6) Press the "Save" button to save the resistance data of the entire test of the tested sample. After the test is completed and the burner is removed, collect the ablation products of the test sample.

5. A device for testing the internal parts of wires and cables under flame impact, which can be used in any one of the test methods of claims 1-4, characterized in that: include: Two relatively fixed lifting platforms; A clamp connected to two lifting platforms, the two clamps are used to clamp and fix the wires and cables; A Bunsen burner is arranged between two lifting platforms and is used for flame impacting electric wires and cables.

6. A testing device according to claim 5, characterized in that: The lifting platform includes two mounting plates arranged upper and lower, one end of the two mounting plates being rotatably connected via a rotating shaft, a micro cylinder being arranged between the other ends of the two mounting plates, the bottom of the micro cylinder being fixedly connected to the mounting plate below, the driving end of the micro cylinder being movably connected to the mounting plate above, and the clamp being installed at one end of the upper mounting plate.

7. A testing device according to claim 6, characterized in that: The clamp is a block with a clamping opening, a bolt is inserted into the block, nuts are threadedly connected at both upper and lower ends of the bolt, and the clamping opening is used to clamp and fix the wires and cables.

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