CN107449642A - Sulfur hexafluoride gas leaks live detection sampling apparatus and the method for sampling - Google Patents

Abstract

The invention discloses a charging detection and sampling device for sulfur hexafluoride gas leakage, which comprises a sampling probe, a sample transmission tube and a vacuum cavity. The sampling probe is connected with the vacuum cavity through the sample transmission tube. The invention provides a charging detection sampling device for sulfur hexafluoride gas leakage, which can sample the gas leakage detection of sulfur hexafluoride electrical equipment running on charge, and use the pressure difference between the vacuum chamber and the sampling probe to pass The sample transmission tube realizes the collection and transmission of air samples under low flow conditions, effectively improves the transmission speed of air samples, reduces the delay time and recovery time of detection, effectively avoids the dilution of air samples, and improves the accuracy of detection. precision. The present invention also provides a method for charged detection and sampling of sulfur hexafluoride gas samples, the method uses the charging detection and sampling device for sulfur hexafluoride gas leakage provided by the present invention, the method has simple steps, and can realize the detection and sampling of sulfur hexafluoride gas samples Live sampling.

Description

Sampling device and sampling method for charged detection of sulfur hexafluoride gas leakage

technical field

The invention relates to the technical field of sulfur hexafluoride gas leakage detection, in particular to a sampling device and a sampling method for charged detection of sulfur hexafluoride gas leakage.

Background technique

Due to its excellent insulation and arc extinguishing performance, sulfur hexafluoride gas is widely used in sulfur hexafluoride switches, sulfur hexafluoride current transformers, sulfur hexafluoride voltage transformers and other sulfur hexafluoride electrical appliances in power systems. equipment. In recent years, sulfur hexafluoride gas leakage has become the most common defect of sulfur hexafluoride electrical equipment. In order to avoid equipment accidents caused by sulfur hexafluoride leakage, the detection of sulfur hexafluoride gas leakage is the important part of the work.

The existing detection methods for sulfur hexafluoride gas leakage can be divided into power failure detection and live detection according to the state of electrical equipment. Power failure detection methods include soap bubble leak detection, vacuum leak detection and leak detector leak detection. Vacuum leak detection is mainly used for GIS equipment installation or disassembly and overhaul, and it is carried out with vacuum drying equipment. First vacuumize the SF6 equipment to 133pa, then continue to vacuumize for 30 minutes, stop the vacuum pump, read the vacuum degree A after waiting for 30 minutes, and read the vacuum degree B after waiting for 5 hours, B-A≤133pa, you can preliminarily determine the sealing performance Good, this method can check the sealing state of the equipment, but it can't find the specific leak point. Soap bubble leak detection is a simple qualitative leak detection method, which can find the leak point more accurately. Use one part of neutral soap and two parts of water to prepare soapy water, and apply it on the tested area. If it foams, it means that there is an air leak. The exact location and air leakage rate of the leak point; but this method requires a lot of work, takes a long time and is inefficient, and cannot effectively find the leak point. Leak detectors are divided into qualitative leak detectors and quantitative leak detectors, among which the sensitivity of quantitative leak detectors is higher, and the detection limit can reach 0.01ppm. Leak detection generally adopts a calibrated sulfur hexafluoride leak detection instrument with high sensitivity, which is close to and moves along the measured surface at a speed of about 20-25mm/s. The detection instrument cannot detect the leakage of sulfur hexafluoride, that is, or combined with the bandage method, resting for 24 hours, and using a quantitative leak detector to detect that the sulfur hexafluoride content in the air at the bandage site does not exceed 30ppm, it is qualified. This method has high sensitivity and can be used to find small leaks. Although the existing quantitative leak detector leak detection method has high sensitivity, it must be used under the condition of power failure of electrical equipment. If it is used for live detection, it must be implemented in combination with a certain sampling method.

Contents of the invention

In view of the above deficiencies, the present invention provides a sulfur hexafluoride gas leakage charging detection sampling device, which can realize the sampling of sulfur hexafluoride gas leakage charging detection. The invention also provides a method for charged detection and sampling of sulfur hexafluoride gas samples.

To achieve the above object, the present invention adopts the following technical solutions:

A charging detection sampling device for sulfur hexafluoride gas leakage, comprising a sampling probe, a sample transmission tube, and a vacuum chamber, and the sampling probe is connected to the vacuum chamber through the sample transmission tube.

Further, the sampling probe includes a filter head, a sampling tube and a handle, and the filter head and the handle are respectively located at two ends of the sampling tube.

Further, the sampling tube includes a sampling tube capillary, a sampling tube rubber interlayer and a sampling tube outer layer, and the sampling tube rubber interlayer and sampling tube outer layer are sequentially sleeved on the outside of the sampling tube capillary.

Further, the capillary of the sampling tube is a fused silica capillary with a silanized surface, and the inner diameter of the capillary of the sampling tube is 150-300 μm; the rubber interlayer of the sampling tube is made of fluororubber; the outer layer of the sampling tube is The material is polytetrafluoroethylene, the outer diameter of the sampling tube is 3-6 mm, and the thickness is 0.4-0.6 mm.

Further, the sample transmission tube includes a transmission tube capillary, a transmission tube rubber interlayer and a transmission tube outer layer, and the transmission tube rubber interlayer and the transmission tube outer layer are sequentially sleeved on the outside of the transmission tube capillary.

Further, the capillary of the transmission tube is a fused silica capillary with a silanized surface, and the inner diameter of the capillary of the transmission tube is 150-300 μm; the material of the rubber interlayer of the transmission tube is fluororubber; the material of the outer layer of the transmission tube is It is polytetrafluoroethylene, the outer diameter of the outer layer of the transmission tube is 2-4mm, and the thickness is 0.3-0.5mm.

Further, the material of the filter head is polytetrafluoroethylene, which is umbrella-shaped.

Further, the material of the handle is polypropylene plastic, the length of the handle is 10-20 cm, and the outer diameter is 2-4 cm.

The present invention also proposes a method for charging detection and sampling of sulfur hexafluoride gas samples that is applicable to the above-mentioned charging detection and sampling device for leakage of sulfur hexafluoride gas, including the following steps:

1) Continuously vacuumize the vacuum chamber so that the pressure difference between the inside of the vacuum chamber and the sampling probe is always maintained at 10 ⁵ Pa, and the pressure inside the vacuum chamber is maintained at 0.5-20Pa during the sampling process ;

2) Put the sampling probe close to the leakage detection part of the sulfur hexafluoride electrical equipment, so that the sampling probe and the leakage detection part of the sulfur hexafluoride electrical equipment are in an equipotential state;

3) Use the sampling probe to suck the air sample from the leakage detection part of the sulfur hexafluoride electrical equipment into the sampling probe, and then send the air sample into the vacuum chamber through the sample transmission tube.

Further, the specific steps of the vacuuming treatment of the vacuum chamber are: first use a diaphragm pump to evacuate to reduce the internal pressure of the vacuum chamber to below 300Pa, and then use a molecular pump to evacuate to reduce the internal pressure of the vacuum chamber to 300 Pa. further reduced to below 20Pa.

Compared with the prior art, the beneficial effects of the present invention are: the present invention provides a charging detection and sampling device for sulfur hexafluoride gas leakage, which can sample the gas leakage detection of sulfur hexafluoride electrical equipment running on charge, It uses the pressure difference between the vacuum chamber and the sampling probe to realize the collection and transmission of air samples under low flow conditions through the sample transmission tube, which effectively improves the transmission speed of air samples and reduces the delay time and recovery time of detection. The dilution of the air sample is effectively avoided, and the detection accuracy is improved. The present invention also provides a method for charged detection and sampling of sulfur hexafluoride gas samples, the method uses the charging detection and sampling device for sulfur hexafluoride gas leakage provided by the present invention, the method has simple steps, and can realize the detection and sampling of sulfur hexafluoride gas samples Live sampling.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings that need to be used in the description of the embodiments.

Fig. 1 is the structural representation of preferred embodiment of the present invention;

Fig. 2 is the transverse sectional schematic view of the sampling pipe of the preferred embodiment of the present invention;

Fig. 3 is a schematic cross-sectional view of a sample transmission tube in a preferred embodiment of the present invention;

Fig. 4 is a schematic diagram of the connection between the vacuum chamber and the sample transmission tube, diaphragm pump, molecular pump, vacuum gauge and sulfur hexafluoride detection unit in a preferred embodiment of the present invention.

Among them, the marks shown in the figure are: 10: sampling probe; 11: filter head; 12: sampling tube; 121: capillary tube of sampling tube; 122: rubber interlayer of sampling tube; 123: outer layer of sampling tube; 13: handle; 20 : Sample transmission tube; 21: Capillary tube of transmission tube; 22: Rubber interlayer of transmission tube; 23: Outer layer of transmission tube; 30: Vacuum chamber; 40: Diaphragm pump; 50: Molecular pump; 60: Vacuum gauge; 70: Hexafluoro Sulfur detection unit.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Apparently, the described embodiments are only some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Please refer to FIG. 1 , the present invention provides a charging detection sampling device for sulfur hexafluoride gas leakage, including a sampling probe 10 , a sample transmission tube 20 , and a vacuum chamber 30 , and the sampling probe 10 is connected to the vacuum chamber 30 through the sample transmission tube 20 .

Further, referring to Fig. 1, the sampling probe 10 includes a filter head 11, a sampling tube 12 and a handle 13, the filter head 11 and the handle 13 are located at the two ends of the sampling tube 12 respectively, and the sampling tube 12 is provided with a handle 13 One end of the sample transfer tube 20 is connected. The filter head 11 , the sampling tube 12 and the handle 13 are arranged coaxially, and the sampling tube 12 passes through the axis of the handle 13 along the axial direction of the handle 13 .

Wherein, the material of the filter head 11 is polytetrafluoroethylene, which is umbrella-shaped and has a grid structure, and its function is to prevent dust particles from entering the sampling tube 12 .

Wherein, the material of handle 13 is polypropylene plastic, and the length of handle 13 is 20cm, and outer diameter is 3cm.

Further, referring to Fig. 2, the sampling tube 12 includes a sampling tube capillary 121, a sampling tube rubber interlayer 122 and a sampling tube outer layer 123, and the sampling tube rubber interlayer 122 and the sampling tube outer layer 123 are sleeved on the sampling tube capillary 121 in turn. outside, and the sampling tube capillary 121, the sampling tube rubber interlayer 122 and the sampling tube outer layer 123 are arranged coaxially. Wherein, the sampling tube capillary 121 is a fused silica capillary with silanization treatment on the surface, and the inner diameter of the sampling tube capillary 121 is 200 μm, and its function is the suction, collection and transmission of air samples; the material of the sampling tube rubber interlayer 122 is fluororubber, its The function is to fill the gap between the capillary 121 of the sampling tube and the outer layer 123 of the sampling tube to act as a buffer, while improving the elasticity of the sampling tube 12; the outer layer 123 of the sampling tube is made of polytetrafluoroethylene, and the outer layer 123 of the sampling tube has an outer diameter 4mm and a thickness of 0.5mm, its function is to improve the mechanical strength and insulation strength of the sampling tube 12.

Further, please refer to FIG. 3 , the sample transfer tube 20 includes a transfer tube capillary 21, a transfer tube rubber interlayer 22 and a transfer tube outer layer 23, and the transfer tube rubber interlayer 22 and the transfer tube outer layer 23 are sequentially sleeved on the transfer tube capillary 21 The outside of the transmission tube, and the transmission tube capillary 21, the transmission tube rubber interlayer 22 and the transmission tube outer layer 23 are coaxially arranged. The sample transfer tube 20 has a length of 7 m and an outer diameter of 4 mm, and its function is the transfer of air samples. Among them, the transfer tube capillary 21 is a fused silica capillary with a silanized surface, and the inner diameter of the transfer tube capillary 21 is 200 μm, and its function is to transmit air samples; the material of the transfer tube rubber interlayer 22 is fluororubber, and its function is to fill the transfer tube capillary The gap between 21 and the outer layer 23 of the transfer tube plays a buffering role, and simultaneously improves the elasticity of the sample transfer tube 20; the material of the outer layer 23 of the transfer tube is polytetrafluoroethylene, and the outer diameter of the outer layer 23 of the transfer tube is 4mm and the thickness is 0.5 mm, its function is to improve the mechanical strength and dielectric strength of the sample transmission tube 20 .

Please refer to Fig. 4, the vacuum chamber 30 is arranged at the end of the sample transmission tube 20, and its function is to form a pressure difference between the vacuum chamber 30 and the sampling probe 10, and the air sample is sucked from the sampling probe 10 through the pressure difference, and then passed through the sample transmission tube 20 is conveyed into a vacuum chamber 30 for air sample collection. The vacuum chamber 30 is provided with five ports, which are respectively connected with the sample transmission tube 20 , the diaphragm pump 40 , the molecular pump 50 , the vacuum gauge 60 and the sulfur hexafluoride detection unit 70 . The diaphragm pump 40 and the molecular pump 50 are used for vacuuming the vacuum chamber 30; the vacuum gauge 60 is used for measuring the pressure in the vacuum chamber 30; the sulfur hexafluoride detection unit 70 is used for the sulfur hexafluoride gas content in the air sample detection.

During implementation, the vacuum chamber 30 is evacuated successively by the diaphragm pump 40 and the molecular pump 50. Since the inner diameter of the sample transmission tube 20 is small and the gas transmission is limited, during the vacuuming process, the inside of the vacuum chamber 30 and the sampling probe The pressure difference at 10 gradually increases. Use the vacuum gauge 60 to measure the pressure in the vacuum chamber 30. When the pressure in the vacuum chamber 30 reaches a certain value (because the pressure at 10 of the sampling probe is basically the same as the atmospheric pressure, the pressure difference can be calculated) , through the sampling probe 10 close to the leakage detection part of the sulfur hexafluoride electrical equipment, make the sampling probe 10 and the leakage detection part of the sulfur hexafluoride electrical equipment in the equipotential state, and use the sampling probe 10 to close the leakage detection part of the sulfur hexafluoride electrical equipment The air sample is sucked into the sampling probe 10 , and then the air sample is sent into the vacuum chamber 30 through the sample transmission tube 20 .

The charged detection and sampling device for sulfur hexafluoride gas leakage proposed by the present invention utilizes the pressure difference between the vacuum chamber 30 and the sampling probe 10 to realize the collection and transmission of air samples under low flow conditions through the sampling tube capillary 121 and the transmission tube capillary 21 , effectively improving the transmission speed of the air sample, reducing the delay time and recovery time of the detection, effectively avoiding the dilution of the air sample, and improving the detection accuracy.

The present invention proposes a method for charging detection and sampling of sulfur hexafluoride gas samples using a sulfur hexafluoride gas leakage charging detection sampling device, including the following steps:

1) Continuously vacuumize the vacuum chamber 30 so that the pressure difference between the interior of the vacuum chamber 30 and the sampling probe 10 is always maintained at 10 ⁵ Pa, and the pressure inside the vacuum chamber 30 is maintained at 0.5-20 Pa during the sampling process; The specific steps of the vacuuming process of the vacuum chamber 30 are: first use the diaphragm pump 10 to evacuate to reduce the internal pressure of the vacuum chamber 30 to below 300Pa, and then use the molecular pump 11 to evacuate to further reduce the internal pressure of the vacuum chamber 30 to Below 20Pa;

2) Put the sampling probe 10 close to the leakage detection part of the sulfur hexafluoride electrical equipment, so that the sampling probe 10 and the leakage detection part of the sulfur hexafluoride electrical equipment are in an equipotential state;

3) Use the sampling probe 10 to suck the air sample from the leakage detection part of the sulfur hexafluoride electrical equipment into the sampling probe 10 , and then send the air sample into the vacuum chamber 30 through the sample transmission tube 20 .

When the sulfur hexafluoride gas sample enters the vacuum chamber 30 , the sulfur hexafluoride gas content in the air sample can be detected through the sulfur hexafluoride detection unit 70 connected to the vacuum chamber 30 .

The method provided by the present invention uses the charged detection sampling device for sulfur hexafluoride gas leakage provided by the present invention. The method has simple steps and can realize charged sampling of sulfur hexafluoride gas samples.

The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Anyone skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present invention. All should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (10)

1. a kind of sulfur hexafluoride gas leaks live detection sampling apparatus, it is characterised in that includes sampling probe（10）, sample Transfer tube（20）, vacuum chamber（30）, the sampling probe（10）Pass through the sample conveying tube（20）With the vacuum chamber（30） It is connected.

2. sulfur hexafluoride gas according to claim 1 leaks live detection sampling apparatus, it is characterised in that the sampling Probe（10）Include filter（11）, sampling pipe（12）And lever（13）, the filter（11）And lever（13）It is located at institute respectively State sampling pipe（12）Both ends.

3. sulfur hexafluoride gas according to claim 2 leaks live detection sampling apparatus, it is characterised in that the sampling Pipe（12）Include sampling pipe capillary（121）, sampling pipe channel rubber（122）With sampling outer tube layer（123）, the sampling pipe Channel rubber（122）With sampling outer tube layer（123）It is sequentially sleeved at the sampling pipe capillary（121）Outside.

4. sulfur hexafluoride gas according to claim 3 leaks live detection sampling apparatus, it is characterised in that the sampling Pipe capillary（121）Pass through the vitreous silica capillary of silanization treatment, the sampling pipe capillary for surface（121）Internal diameter For 150 ~ 300 μm；The sampling pipe channel rubber（122）Material be fluorubber；The sampling outer tube layer（123）Material be Polytetrafluoroethylene (PTFE), the sampling outer tube layer（123）External diameter is 3 ~ 6mm, and thickness is 0.4 ~ 0.6mm.

5. sulfur hexafluoride gas according to claim 1 leaks live detection sampling apparatus, it is characterised in that the sample Transfer tube（20）Include transfer tube capillary（21）, transfer tube channel rubber（22）With transmission outer tube layer（23）, the transmission Pipe channel rubber（22）With transmission outer tube layer（23）It is sequentially sleeved at the transfer tube capillary（21）Outside.

6. sulfur hexafluoride gas according to claim 5 leaks live detection sampling apparatus, it is characterised in that the transmission Pipe capillary（21）Pass through the vitreous silica capillary of silanization treatment, the transfer tube capillary for surface（21）Internal diameter is 150~300μm；The transfer tube channel rubber（22）Material be fluorubber；The transmission outer tube layer（23）Material be poly- four PVF, the transmission outer tube layer（23）External diameter is 2 ~ 4mm, and thickness is 0.3 ~ 0.5mm.

7. sulfur hexafluoride gas according to claim 2 leaks live detection sampling apparatus, it is characterised in that the filter （11）Material be polytetrafluoroethylene (PTFE), in umbrella.

8. sulfur hexafluoride gas according to claim 2 leaks live detection sampling apparatus, it is characterised in that the lever （13）Material be polypropylene plastics, the lever（13）Length be 10 ~ 20cm, external diameter is 2 ~ 4cm.

9. a kind of usage right requires the sulfur hexafluoride gas leakage live detection sampling apparatus described in any one of 1-8 to carry out The method of sulfur hexafluoride gas sample live detection sampling, it is characterised in that include following steps：

1）To the vacuum chamber（30）Continuous vacuumize process is carried out, makes the vacuum chamber（30）The internal and sampling probe （10）Between pressure differential maintain 10 all the time⁵Pa, vacuum chamber in sampling process（30）Internal pressure maintains 0.5 ~ 20Pa；

2）By the sampling probe（10）Close to sulfur hexafluoride electrical equipment leak detection position, make the sampling probe（10）With Sulfur hexafluoride electrical equipment leak detection position is in equipotential state；

3）Use the sampling probe（10）It will be adopted described in the air sample suction at sulfur hexafluoride electrical equipment leak detection position Sample is popped one's head in（10）It is interior, then pass through the sample conveying tube（20）Air sample is sent into the vacuum chamber（30）It is interior.

10. the method for sulfur hexafluoride gas sample live detection sampling according to claim 9, it is characterised in that described Vacuum chamber（30）Vacuumize process concretely comprise the following steps：First being vacuumized using diaphragm pump makes the vacuum chamber（30）Inside pressure Power is reduced to below 300Pa, and reusing molecular pump and vacuumizing makes the vacuum chamber（30）Internal pressure be further reduced to Below 20Pa.