Cable pyrolysis gas collecting device

Abstract

The invention relates to a cable pyrolysis gas collecting device in the technical field of cable fault diagnosis and early warning, which comprises a gas collecting bottle, a gas collecting sleeve sleeved outside a cable and a high-pressure bottle for storing high-pressure air, and is characterized in that the gas collecting bottle, the gas collecting sleeve and the high-pressure bottle are respectively provided with a first pressure gauge, a second pressure gauge and a third pressure gauge for measuring internal pressure; a bottle body of the gas collection bottle is made of a transparent heat-resistant material capable of expanding along with internal pressure; the gas collection sleeve comprises a heat transfer sleeve section, heat insulation sleeve sections are connected to the two ends of the heat transfer sleeve section, transition sleeve sections are connected to the outer ends of the two heat insulation sleeve sections, sealing hoops used for clamping and extruding the transition sleeve sections to be tightly attached to a cable for sealing are clamped to the end walls of the outer ends of the two transition sleeve sections in a sleeving mode, and a gas inlet pipe and a gas outlet pipe are arranged on the end walls of the inner ends of the two transition sleeve sections respectively. The air inlet pipe and the air outlet pipe are respectively and correspondingly communicated with openings of the high-pressure bottle and the air collecting bottle through guide pipes with control valves; the collecting device can more completely collect characteristic gas, and the diversity and accuracy of measurement are improved.

Description

Technical Field

[0001] The invention relates to the technical field of cable fault diagnosis and early warning, and in particular to a cable pyrolysis gas collection device. Background Art

[0002] It is well known that cable materials, especially cable insulation materials, may deteriorate or decompose during long-term operation under the influence of factors such as ambient temperature and current load, and produce some characteristic gases. By monitoring and analyzing these gases, the deterioration of the cable can be effectively understood, and necessary maintenance or replacement measures can be taken. Among them, temperature has an important influence on the pyrolysis process of cable insulation materials. Generally speaking, the higher the temperature, the faster the degradation rate of the cable material. By analyzing the gas decomposition characteristics of the cable under different temperature conditions, a relationship model between different temperatures and gas concentrations can be established. The whole process includes steps such as experimental data collection, gas composition analysis and relationship model establishment. The Chinese invention patent with announcement number CN115655812A discloses a sampling device and sampling method for the pyrolysis products of cable insulation layers. A plurality of collection tubes are arranged to surround the corresponding cables to be burned and pyrolyzed, and the movement of the piston in the collection tube is controlled to absorb and collect the characteristic gases generated by the pyrolysis of the cables. However, there are three defects in the prior art: first, placing the pyrolysis cable in an external environment is not conducive to pyrolysis temperature control, and thus is not conducive to subsequent data analysis and model building; second, placing the pyrolysis cable in an external environment cannot ensure that the piston cylinder can completely collect the decomposition characteristic gases, which may lead to deviations in subsequent concentration measurements; third, the gas pressure collected by the piston cylinder is relatively large and unstable, so that some efficient measurement methods for gas types and concentrations cannot be used directly, such as the infrared absorption spectrum measurement method, which will cause differences in the absorption of infrared light by the gas due to different gas pressures, thereby causing measurement errors. Summary of the invention

[0003] In order to overcome the deficiencies in the background technology and solve the existing technical problems, the present invention discloses a cable pyrolysis gas collection device, which can more completely collect characteristic gases and improve the diversity and accuracy of measurements.

[0004] To achieve the above object, the present invention adopts the following technical solution: A cable pyrolysis gas collection device comprises a gas collecting bottle, a gas collecting sleeve sleeved outside the cable and a high-pressure bottle for storing high-pressure air, the gas collecting bottle, the gas collecting sleeve and the high-pressure bottle are respectively provided with a first pressure gauge, a second pressure gauge and a third pressure gauge for measuring internal pressure, the body of the gas collecting bottle is made of a transparent heat-resistant material that can expand with the internal pressure; the gas collecting sleeve comprises a heat transfer sleeve section, both ends of the heat transfer sleeve section are connected with a heat insulation sleeve section, the outer ends of the two heat insulation sleeve sections are connected with a transition sleeve section, the outer end walls of the two transition sleeve sections are clamped with a sealing clamp for clamping the transition sleeve section to seal against the cable, the inner end walls of the two transition sleeve sections are respectively provided with an air inlet pipe and an air outlet pipe, the air inlet pipe and the air outlet pipe are respectively connected with the bottle mouths of the high-pressure bottle and the gas collecting bottle through a conduit with a control valve.

[0005] Furthermore, an ignition unit corresponding to the cable is installed on the middle wall of the heat transfer sleeve section.

[0006] Furthermore, the central sleeve wall of the heat transfer sleeve section is concave to form a heat conduction portion that contacts the cable.

[0007] Furthermore, the heat-insulating sleeve section is provided with an annular cavity for storing pure water.

[0008] Furthermore, the outer end of the transition sleeve is reduced in diameter and is made of rubber material.

[0009] Furthermore, the sealing clamp is configured as a throat clamp, and two of them are spaced apart and arranged side by side along the axial direction of each transition sleeve segment, and a plurality of convex tooth rings are arranged side by side along the axial direction on the inner wall of the outer end of the transition sleeve segment.

[0010] Furthermore, the air inlet pipe and the air outlet pipe are respectively located at the lower end and the higher end of the air collecting sleeve.

[0011] Furthermore, the body of the gas collecting bottle is made of a transparent film-like polysiloxane, polytetrafluoroethylene, polycarbonate or polyimide material.

[0012] Furthermore, the air collecting sleeve is radially divided into two half sleeves, wherein a sealing strip is fixed on the cut surface of one half of the sleeve, and a sealing groove corresponding to the clamping sealing strip is provided on the cut surface of the other half of the sleeve.

[0013] Furthermore, the method for using the cable pyrolysis gas collection device comprises the following steps: S1. firstly place the gas collecting sleeve outside the cable section to be pyrolyzed, and then tighten the sealing clamp to seal the two ports of the gas collecting sleeve against the cable; the initial pressure of the high-pressure air in the high-pressure bottle is at least 3 times the atmospheric pressure; S2. apply the pyrolysis temperature to the cable through the heat transfer sleeve section of the gas collecting sleeve; S3. when the second pressure gauge measures the pressure change, open the control valve of the gas collecting bottle, and control and adjust the control valve of the high-pressure bottle so that the pressure of the gas collecting sleeve during the pyrolysis process is maintained at 1 to 1.2 times the atmospheric pressure; S4. when the pressure in the gas collecting sleeve reaches 1.2 times the atmospheric pressure, open the control valve of the high-pressure bottle, monitor the pressure changes of the second pressure gauge and the first pressure gauge, and when the pressure of the first pressure gauge reaches 1.5 atmospheric pressures, quickly close the control valve of the gas collecting bottle to complete the collection of characteristic gases.

[0014] Due to the adoption of the above-mentioned technical solution, the present invention has the following beneficial effects: The cable pyrolysis gas collection device disclosed in the present invention isolates the external environment from the entire collection process to avoid leakage, generates air flow through pressure changes, and can thereby send the characteristic gas generated in the gas collecting sleeve into the gas collecting bottle for collection in a relatively more complete and uniform manner, and the cable section to be pyrolyzed is placed in the gas collecting sleeve, which is also convenient for temperature control and avoids energy waste; more importantly, the transparent gas collecting bottle can adaptively expand according to the amount of collected gas, thereby further reducing the gas collection pressure compared to traditional piston thrust forced collection, maintaining the uniformity of the collected gas and the stability of the gas pressure, and can subsequently release the gas for contact reaction measurement of type and concentration, and can also directly adopt non-contact measurement methods such as infrared absorption spectroscopy measurement methods for measurement, thereby ensuring the diversity and accuracy of the measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the implementation structure of the present invention; Figure 2 It is a schematic diagram of the cross-sectional structure of the gas collecting sleeve.

[0016] In the figure: 1. gas collecting bottle; 101. first pressure gauge; 2. gas collecting sleeve; 201. heat transfer sleeve section; 202. heat insulation sleeve section; 203. transition sleeve section; 204. air inlet pipe; 205. air outlet pipe; 206. annular cavity; 207. heat transfer part; 3. high-pressure bottle; 301. third pressure gauge; 4. sealing clamp. DETAILED DESCRIPTION

[0017] The technical solution of the present invention will be described below in conjunction with the drawings in the embodiments of the present invention. In the description, it should be understood that if there are terms such as "upper", "lower", "front", "back", "left", "right", etc. indicating directions or positional relationships, they only correspond to the drawings of the present invention and are for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific direction. Embodiment 1:

[0018] Combined with Figure 1-2 The cable pyrolysis gas collection device comprises a gas collection bottle 1, a gas collection sleeve 2 sleeved outside the cable and a high-pressure bottle 3 for storing high-pressure air. The gas collection bottle 1, the gas collection sleeve 2 and the high-pressure bottle 3 are respectively provided with a first pressure gauge 101, a second pressure gauge and a third pressure gauge 301 for measuring the internal pressure. The body of the gas collection bottle 1 is made of a transparent heat-resistant material that can expand with the internal pressure. Specifically, the body of the gas collection bottle 1 is made of a transparent film-like polysiloxane, polytetrafluoroethylene, polycarbonate or polyimide material, which has a certain flexibility or elasticity to meet the requirements of gas collection and expansion of volume. In addition, because the temperature of the pyrolysis gas is relatively high, the heat resistance requirement is met. At the same time, if it is necessary to directly use the infrared absorption spectrum measurement method to measure the type and concentration of the characteristic gas, the transparent light transmission requirement must also be met. The gas collecting sleeve 2 includes a heat transfer sleeve section 201, through which the pyrolysis temperature is applied to the cable. Of course, a thermometer can be installed on the outer wall of the heat transfer sleeve section 201 to measure the temperature, thereby meeting the monitoring requirements of different test temperatures; as needed, the central sleeve wall of the heat transfer sleeve section 201 is concave to form a heat conducting portion 207 that contacts the cable, that is, it can directly conduct open flame or electric heating from the heat conducting portion 207 to transfer the temperature to the cable, simulating the ambient temperature to cause pyrolysis; both ends of the heat transfer sleeve section 201 are connected to a heat insulating sleeve section 202. When the pyrolysis test temperature is high, the heat insulating sleeve section 202 can be used for insulation to prevent affecting the sealing effect of the two ends of the gas collecting sleeve 2 and causing the sealing clamp 4 to overheat. High, inconvenient to disassemble; according to needs, the insulation sleeve section 202 is provided with an annular cavity 206 for storing pure water, pure water has a large specific heat capacity, and can absorb and insulate heat; the outer ends of the two insulation sleeve sections 202 are connected to the transition sleeve sections 203, and the outer end walls of the two transition sleeve sections 203 are clamped with a sealing clamp 4 for clamping the transition sleeve section 203 tightly against the cable for sealing; according to needs, the outer end of the transition sleeve section 203 is reduced in diameter and set to rubber material to facilitate deformation and extrusion sealing; in addition, the sealing clamp 4 is set as a throat clamp, and two are arranged side by side along the axial interval of each transition sleeve section 203, and the outer end inner wall of the transition sleeve section 203 is provided with a plurality of convex tooth rings side by side along the axial direction, which greatly improves the sealing effect and prevents the characteristic gas from leaking out; The inner end walls of the two transition sleeve sections 203 are respectively provided with an air inlet pipe 204 and an air outlet pipe 205, which are respectively connected to the bottle mouths of the high-pressure bottle 3 and the gas collecting bottle 1 through a conduit with a control valve. The control valve can be set as a manual regulating valve to manually control the switch and flow, and can also be set as an automatic control valve. After the first pressure gauge 101, the second pressure gauge and the third pressure gauge 301 are set as pressure sensors at the same time, data feedback, monitoring and measurement, parameter setting and switch flow control can be performed by an additional controller at the same time; according to needs, the air inlet pipe 204 and the air outlet pipe 205 are respectively located at the low end and the high end of the gas collecting sleeve 2, so that the cold gas of the intake air can push the hot gas of the pyrolysis upward for collection.

[0019] The cable pyrolysis gas collection device of the present invention comprises the following steps: Step 1: First, place the gas collection sleeve 2 outside the cable section to be pyrolyzed, then tighten the sealing clamp 4, and seal the two ends of the gas collection sleeve 2 against the cable; the initial pressure of the high-pressure air in the high-pressure bottle 3 is at least 3 times the atmospheric pressure; Step 2: Apply pyrolysis temperature to the cable through the heat transfer sleeve section 201 of the gas collecting sleeve 2; the specific pyrolysis temperature is determined according to the test requirements, and of course different temperatures can be set to collect tests and obtain different experimental data; Step 3: When the second pressure gauge measures the pressure change, open the control valve of the gas collecting bottle 1, and control and adjust the control valve of the high-pressure bottle 3, so that the pressure of the gas collecting sleeve 2 during the pyrolysis process is maintained at 1 to 1.2 times the atmospheric pressure; under this limitation, the amount of characteristic gas generated is related to the pyrolysis duration. If there are specific test requirements for the pyrolysis duration, in order to achieve this time and keep the pressure, it is necessary to change the collection volume of the gas collecting bottle 1. In general, the longer the required pyrolysis test time, the larger the volume of the gas collecting bottle 1 needs to be; Step 4. When the pressure in the gas collecting sleeve 2 reaches 1.2 times the atmospheric pressure, open the control valve of the high-pressure bottle 3 and monitor the pressure changes of the second pressure gauge and the first pressure gauge 101. When the pressure of the first pressure gauge 101 reaches 1.5 times the atmospheric pressure, quickly close the control valve of the gas collecting bottle 1 to complete the collection of the characteristic gas. Embodiment 2:

[0020] The difference from the first embodiment is that, if a direct ignition pyrolysis test is desired on the cable, an ignition unit corresponding to the cable can be installed on the middle wall of the heat transfer sleeve 201. Of course, during combustion, it is necessary to adjust the release of the high-pressure bottle 3 to provide the oxygen required for combustion. Embodiment three:

[0021] The difference from Example 1 is that if one wants to test the online cable directly, the air collecting sleeve 2 cannot be inserted from the end of the cable. The air collecting sleeve 2 can be designed to be radially divided into two half-suites, wherein the cut surface of one half of the suit is fixed with a sealing strip, and the cut surface of the other half of the suit is provided with a sealing groove corresponding to the snap-on sealing strip. The air collecting sleeve 2 is directly put on the outside of the cable in the form of the two half-suites being sealed against each other. Of course, in order to ensure that the two half-suites are tightly connected, the outer sleeve clamp can also be used to clamp them.

[0022] The parts of the present invention that are not described in detail are prior art. It is obvious to those skilled in the art that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, no matter from which point of view, the above-mentioned embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the attached claims rather than the above description. Therefore, it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the present invention, and any figure marks in the claims should not be regarded as limiting the content of the claims involved.

Claims

1. A cable pyrolysis gas collection device, characterized by: The invention comprises an air collecting bottle (1), an air collecting sleeve (2) sleeved outside a cable, and a high-pressure bottle (3) for storing high-pressure air, wherein the air collecting bottle (1), the air collecting sleeve (2), and the high-pressure bottle (3) are respectively provided with a first pressure gauge (101), a second pressure gauge, and a third pressure gauge (301) for measuring internal pressure, and the body of the air collecting bottle (1) is made of a transparent heat-resistant material capable of expanding with internal pressure; the air collecting sleeve (2) comprises a heat transfer sleeve section (201), and both ends of the heat transfer sleeve section (201) are connected to a heat insulation sleeve section (201). 02), the outer ends of the two heat-insulating sleeve sections (202) are connected to the transition sleeve sections (203), the outer end walls of the two transition sleeve sections (203) are clamped with a sealing clamp (4) for clamping the transition sleeve sections (203) tightly against the cable for sealing, and the inner end walls of the two transition sleeve sections (203) are respectively provided with an air inlet pipe (204) and an air outlet pipe (205), and the air inlet pipe (204) and the air outlet pipe (205) are respectively connected to the bottle mouths of the high-pressure bottle (3) and the gas collection bottle (1) through a conduit with a control valve.

2. The cable pyrolysis gas collection device according to claim 1, characterized in that: An ignition unit corresponding to the cable is installed on the middle wall of the heat transfer sleeve section (201).

3. The cable pyrolysis gas collection device according to claim 1, characterized in that: The central sleeve wall of the heat transfer sleeve section (201) is concave to form a heat conducting portion (207) that contacts the cable.

4. The cable pyrolysis gas collection device according to claim 1, characterized in that: The heat-insulating sleeve section (202) is provided with an annular cavity (206) for storing pure water.

5. The cable pyrolysis gas collection device according to claim 1, characterized in that: The outer end of the transition sleeve section (203) has a reduced diameter and is made of rubber material.

6. The cable pyrolysis gas collection device according to claim 5, characterized in that: The sealing clamp (4) is configured as a throat clamp, and two of them are arranged side by side at intervals along the axial direction of each transition sleeve segment (203); and a plurality of convex tooth rings are arranged side by side along the axial direction on the inner wall of the outer end of the transition sleeve segment (203).

7. The cable pyrolysis gas collection device according to claim 1, characterized in that: The air inlet pipe (204) and the air outlet pipe (205) are respectively located at the lower end and the upper end of the air collecting sleeve (2).

8. The cable pyrolysis gas collection device according to claim 1, characterized in that: The body of the gas collecting bottle (1) is made of a transparent film-like material such as polysiloxane, polytetrafluoroethylene, polycarbonate or polyimide.

9. The cable pyrolysis gas collection device according to claim 1, characterized in that: The air collecting sleeve (2) is radially divided into two half sleeves, wherein a sealing strip is fixed to the cut surface of one half of the sleeve, and a sealing groove corresponding to the clamping sealing strip is provided on the cut surface of the other half of the sleeve.

10. The cable pyrolysis gas collection device according to claim 1, characterized in that: The method for using the cable pyrolysis gas collection device comprises the following steps: S1. First, the gas collection sleeve (2) is placed outside the cable section to be pyrolyzed, and then the sealing clamp (4) is tightened to seal the two ends of the gas collection sleeve (2) against the cable; the initial pressure of the high-pressure air in the high-pressure bottle (3) is at least 3 times the atmospheric pressure; S2, applying pyrolysis temperature to the cable through the heat transfer sleeve section (201) of the gas collecting sleeve (2); S3. When the second pressure gauge measures the pressure change, the control valve of the gas collecting bottle (1) is opened, and the control valve of the high-pressure bottle (3) is controlled and adjusted so that the pressure of the gas collecting sleeve (2) during the pyrolysis process is maintained at 1 to 1.2 times the atmospheric pressure; S4. When the pressure in the gas collection sleeve (2) reaches 1.2 times the atmospheric pressure, open the control valve of the high-pressure bottle (3), monitor the pressure changes of the second pressure gauge and the first pressure gauge (101), and when the pressure of the first pressure gauge (101) reaches 1.5 times the atmospheric pressure, quickly close the control valve of the gas collection bottle (1) to complete the collection of the characteristic gas.

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