SF6 decomposer sensor and preparation method thereof

Abstract

The invention relates to an SF6 decomposer sensor and a preparation method thereof. The SF6 decomposer sensor comprises a first electrode, a second electrode and a third electrode which are sequentially stacked; a micron column array is arranged on the surface of one side, close to the second electrode, of the first electrode, and at least one through hole is formed in the first electrode; a micron column array is arranged on the surface of one side, close to the first electrode, of the second electrode, and at least one through hole is formed in the second electrode; a micron column array is arranged on the surface of one side, close to the second electrode, of the third electrode, and a groove is formed in the third electrode; wherein each micron column in the micron column array on each electrode is made of a compound of SU-8 photoresist and a silicon material; a first supporting piece is arranged between the first electrode and the second electrode so as to isolate the first electrode from the second electrode; and a second supporting piece is arranged between the second electrode and the third electrode so as to isolate the second electrode from the third electrode. According to the scheme, the SF6 decomposer sensor is high in sensitivity.

Description

Technical Field

[0001] The present application relates to the field of sensor technology, in particular to a SF 6 Decomposition product sensor and preparation method thereof. Background Art

[0002] The safe and reliable operation of the power system is particularly important, and the safe operation status of high-voltage equipment, as an important part of the power system, naturally attracts much attention. 6 Sulfur hexafluoride (SF6) gas is widely used in high-voltage equipment such as GIS (Gas Insulated Switchgear), high-voltage transformers, high-voltage circuit breakers, and gas-insulated pipeline transmission lines because of its arc extinguishing ability far greater than air and its high voltage breakdown withstand capacity. In order to ensure the safety and stability of high-voltage equipment, SF 6 Gas leak detection, moisture content detection and SF 6 Decomposition product detection is indispensable in the preventive test and acceptance test of high-voltage equipment. 6 The decomposition product detection method has the advantages of being less affected by on-site electromagnetic interference and being able to accurately locate defects or gas chamber failures, and has been widely used in the power industry.

[0003] Currently SF 6 Common detection methods for decomposition product detection technology include chemical analysis, gas detection tube method, gas chromatography, spectroscopy, sensor detection method, etc. Among them, sensor detection method has become a hot research topic due to its advantages such as simple use and low detection limit. 6 The sensitivity of the decomposition product sensor is low and needs to be further improved. Summary of the invention

[0004] Based on this, it is necessary to provide a SF with higher sensitivity to address the above technical issues. 6 Decomposition product sensor and preparation method thereof.

[0005] In the first aspect, the present application provides a SF 6 Decomposition product sensor, the SF 6The decomposition product sensor comprises a first electrode, a second electrode and a third electrode which are stacked in sequence; a micrometer column array is arranged on the surface of the first electrode close to the second electrode, and at least one through hole is arranged on the first electrode; a micrometer column array is arranged on the surface of the second electrode close to the first electrode, and at least one through hole is arranged on the second electrode; a micrometer column array is arranged on the surface of the third electrode close to the second electrode, and a groove is arranged on the third electrode; wherein the material of each micrometer column in the micrometer column array on each electrode is a composite of SU-8 photoresist and silicon material; a first support is arranged between the first electrode and the second electrode to isolate the first electrode and the second electrode; a second support is arranged between the second electrode and the third electrode to isolate the second electrode and the third electrode.

[0006] In one embodiment, the orthographic projection of the second electrode on the third electrode covers the orthographic projection of the first electrode on the third electrode; and the orthographic projection of the second electrode on the third electrode covers at least a portion of the third electrode.

[0007] In one embodiment, the micro-pillar array on the third electrode is arranged around the groove.

[0008] In one embodiment, SF 6 The decomposition product sensor also includes a battery; the first electrode is connected to the negative electrode of the battery; and the second electrode is connected to the positive electrode of the battery.

[0009] In one embodiment, SF 6 The decomposition product sensor further includes a current detector; a first end of the current detector is connected to the third electrode, and a second end of the current detector is connected to the second electrode.

[0010] In one embodiment, SF 6 The decomposition product sensor further includes a shell, which is used to encapsulate the first electrode, the second electrode and the third electrode.

[0011] In one embodiment, SF 6 The decomposition product sensor also includes a pointer arranged on the shell, a concentration etching line arranged on the shell, and a driver and a single-chip microcomputer arranged in the inner cavity of the shell; the single-chip microcomputer is connected to the current detector; one end of the driver is connected to the single-chip microcomputer, and the other end of the driver is connected to the pointer.

[0012] In one embodiment, SF 6 The decomposition product sensor also includes an early warning indicator light, which is connected to the single-chip microcomputer.

[0013] In one embodiment, SF 6 The decomposition product sensor also includes a charging interface for connecting to an external power source to charge the battery.

[0014] In the second aspect, the present application also provides a SF 6 A method for preparing a decomposition product sensor, the method comprising: obtaining a first electrode and a second electrode provided with at least one through hole, and obtaining a third electrode provided with a groove; wherein the materials of the first electrode, the second electrode and the third electrode are all silicon materials; using a deep reactive ion etching method based on an alternating reciprocating process to prepare micrometer column arrays on the first electrode, the second electrode and the third electrode respectively, wherein for each electrode, in the process of preparing the micrometer column array, SU-8 photoresist is applied on the surface of the electrode to be targeted by a spin coating process to form a SU-8 single layer, the SU-8 single layer is printed by a two-photon molding technology, and after the printing is completed, an ethanol solvent is used to dissolve the uncured SU-8 photoresist to obtain the micrometer column array on the surface of the electrode to be targeted; a glass sheet is bonded between the first electrode and the second electrode to form a first support member, and a glass sheet is bonded between the second electrode and the third electrode to form a second support member.

[0015] The above SF 6 The decomposition product sensor includes a first electrode, a second electrode and a third electrode which are stacked in sequence; a micrometer column array is arranged on the surface of the first electrode close to the second electrode, and at least one through hole is arranged on the first electrode; a micrometer column array is arranged on the surface of the second electrode close to the first electrode, and at least one through hole is arranged on the second electrode; a micrometer column array is arranged on the surface of the third electrode close to the second electrode, and a groove is arranged on the third electrode; wherein the material of each micrometer column in the micrometer column array on each electrode is a composite of SU-8 photoresist and silicon material; a first support is arranged between the first electrode and the second electrode to isolate the first electrode and the second electrode; a second support is arranged between the second electrode and the third electrode to isolate the second electrode and the third electrode. Compared with a micrometer column array having only silicon material, a micrometer column array having a composite material of SU-8 photoresist and silicon material can further enhance the electric field effect and promote the occurrence of field emission phenomenon, thereby improving SF 6 Decomposition product sensor for SF 6 The sensitivity and accuracy of the detection of decomposition products. In addition, SU-8 photoresist has the characteristics of flexibility, so in SF 6 When the decomposition product sensor is subjected to vibration, the micro-columns in the micro-column array are not easily broken, thereby avoiding short circuits of the electrodes and thus extending the SF 6 Life of the decomposition product sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 In one embodiment, SF 6 A three-dimensional schematic diagram of a decomposition product sensor;

[0018] Figure 2 In one embodiment, SF 6 Top view of the three electrodes in the decomposition product sensor;

[0019] Figure 3 In one embodiment, SF 6 A schematic diagram of a process for preparing a decomposition product sensor;

[0020] Figure 4 In one embodiment, SF 6 The decomposition product sensor is excited by DC to SO 2 Response characteristic curve of

[0021] Figure 5 In one embodiment, SF 6 The decomposition product sensor reacts to H under DC excitation. 2 Response characteristic curve of S;

[0022] Figure 6 In one embodiment, SF 6 Response characteristic curve of decomposition product sensor to CO under DC excitation;

[0023] Figure 7 In one embodiment, SF 6 The decomposition product sensor reacts to SO under pulse excitation 2 Response characteristic curve of

[0024] Figure 8 In one embodiment, SF 6 The decomposition product sensor reacts to H under pulse excitation. 2 Response characteristic curve of S;

[0025] Fig. 9 In one embodiment, SF 6 Response characteristic curve of decomposition product sensor to CO under pulse excitation;

[0026] Fig.10 In another embodiment, SF 6 The decomposition product sensor reacts to SO under pulse excitation2 Response characteristic curve of

[0027] Fig.11 In another embodiment, SF 6 The decomposition product sensor reacts to H under pulse excitation. 2 Response characteristic curve of S;

[0028] Fig.12 In another embodiment, SF 6 Response characteristic curve of the decomposition product sensor to CO under pulse excitation. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0030] The safe and reliable operation of the power system is particularly important, and the safe operation status of high-voltage equipment, as an important part of the power system, naturally attracts much attention. 6 Sulfur hexafluoride (SF6) gas is widely used in high-voltage equipment such as GIS equipment, high-voltage transformers, high-voltage circuit breakers, and gas-insulated pipeline transmission lines because of its arc extinguishing ability far greater than air and its high voltage breakdown withstand capacity. In order to ensure the safety and stability of high-voltage equipment, SF 6 Gas leak detection, moisture content detection and SF 6 Decomposition product detection is indispensable in the preventive test and acceptance test of high-voltage equipment. 6 The decomposition product detection method has the advantages of being less affected by on-site electromagnetic interference and being able to accurately locate defects or gas chamber failures, and has been widely used in the power industry.

[0031] SF 6 Common detection methods for decomposition product detection technology include chemical analysis, gas detection tube method, gas chromatography and sensor detection method. Among them, the chemical analysis method is very susceptible to interference in the actual environment, thus affecting the measurement results, and it takes a long time, and the test steps are also very cumbersome; the gas detection tube method is easily affected by temperature and humidity, has a short storage time, and has low measurement accuracy, so it is currently only used as an auxiliary measurement on site; the detection effect of the chromatographic column of the gas chromatography method can only be accurately analyzed in a laboratory environment, and is not suitable for online monitoring scenarios; the sensor detection method has become a hot research topic due to its advantages such as simple use and low detection limit.

[0032] SF 6Mixed gas decomposition products can be tested, and up to 16 decomposition products can be tested in one injection. However, the test results of different units vary greatly, the detection accuracy is low, and it is difficult to compare.

[0033] Based on infrared spectroscopy, a variety of SF 6 The minimum detection limit of decomposition products is ppm (concentration unit, indicating the mass of solute accounts for parts per million of the total solution mass) level, the detection time is short, and continuous online monitoring can be achieved, but SF 6 The absorption peaks of SF and its partial decomposition products overlap, making it difficult to identify the characteristic absorption components. Standard gas must be used to obtain a reference spectrum to calibrate the test results. 6 The content of the decomposition components is low, the absorption is weak, the relative change between the incident spectrum and the spectrum after absorption is small, and the detection sensitivity is low.

[0034] Based on ultraviolet spectrum detection technology, SO is detected by simulating GIS partial discharge 2 (Sulfur dioxide) concentration, the detection range is 0ppm-12ppm, the minimum detection limit is 1ppm, its detection accuracy is high, but it has the disadvantage of a small detection range.

[0035] Based on the principle of photoacoustic spectroscopy, the oil and gas data of transformers at different voltages and times can be analyzed experimentally to find that SF 6 The method can be used to detect the fault derivatives in the equipment, but the accuracy and detection precision of this method are not high, and it can only be used as one of the bases for fault judgment.

[0036] Gas sensors based on various nanomaterials for detecting SF 6 The results show that the resistance of the gas sensor decreases with the discharge time, which can reflect the overall situation of the decomposition components, but cannot detect SF 6 The precise concentration of each component of the decomposition product.

[0037] Based on nickel chloride doped multi-walled carbon nanotube sensor, the sensor's response to SF 6 Simulated discharge products, 20ppmSOF 2 (sulfur-based halides) and 500ppm SO 2 Gas sensitive response to SOF 2 and SO 2 They have similar response characteristics and cannot effectively distinguish between the two gases; they have poor gas sensitivity to SO2 and low sensitivity.

[0038] Based on the hydroxyl-modified single-walled carbon nanotube gas sensor, the experiment detected SOF at two concentration points of 250ppm and 500ppm 2 、SO 2 and CF 4(carbon tetrafluoride) gas, and found that the sensor responded to different concentrations of gas; and to 0-500ppm SO 2 Gas sensing experiments were carried out, and the change rate of sensor resistance approximately satisfied a linear relationship with the change in SO2 concentration, but the recovery process of the sensor was relatively slow.

[0039] Pt (platinum) doped TiO prepared by electrochemical pulse deposition 2 (TiO2) nanotube arrays are used as sensitive materials. 2 Nanotube sensor, for 25ppm-100ppm SO 2 、SOF 2 The gas-sensitive response experiment was carried out, and the response curve was good. However, the sensor needs to be irradiated with ultraviolet light for desorption after a period of use, otherwise the initial resistance and sensitivity will be affected, thus affecting the measurement accuracy of the sensor.

[0040] The three-electrode carbon nanotube ionization sensor was used to study other fault characteristic gases of the transformer. The sensor was experimentally tested for 0ppm-400ppm H 2 S (hydrogen sulfide) and 0ppm-400ppm C 2 H 2 The response curve of (acetylene) is good under single value, but the structural design of the sensor easily causes the cathode to be bombarded by charged particles and thus damaged. The damage of the cathode will cause the collector current of the sensor to decrease, thus making it impossible for the sensor to detect the gas. In addition, the sensor working in the discharge area will generate a lot of heat, which will cause the carbon tube to be destroyed, greatly affecting the life of the sensor. Using carbon nanotube ionization sensor to detect SF 6 Decomposition product SO 2 or SOF 2 Its detection range is 0ppm-110ppm, and it has good single-value sensitivity characteristics, but the sensor has a short life and is easily damaged.

[0041] The new sensor made of gold nanopore structure has high sensitivity and good response characteristics in gas detection, but it has the problem of large hysteresis error. Radio frequency is used as the excitation source to explore the sensor's response to H 2 The response characteristics of S have obtained a good single-value response curve, which is helpful to achieve the 2 However, the sensor requires high power consumption and has a small detection range. In the study, a single-sided micron column structure electrode was used, which helps to increase the interaction between the sensor and the gas and improve the sensitivity and selectivity of the detection. In addition, 12M RF excitation is used to achieve CO (carbon monoxide) and CH 4The detection results show that the minimum detection limits are 25ppm and 10ppb, and the maximum sensitivity is -8.78×10-2nA / ppm and -3.78×10+2nA / ppm, respectively. However, the hysteresis of the sensor is poor under RF excitation, and it is unable to achieve repeatable measurement of gas and the power consumption is high.

[0042] In summary, the existing 6 CO and SO in decomposition products 2 , H 2 The sensor for detecting the three gas concentrations has the disadvantages of low sensitivity, low detection accuracy and small range. Based on this, it is necessary to propose effective technical means to solve the above technical problems. The technical scheme of the present application and how the technical scheme of the present application solves the above technical problems are described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0043] In one embodiment, Figure 1 As shown, the present application provides a SF 6 Schematic diagram of the decomposition product sensor. 6 The decomposition product sensor comprises: a first electrode 101, a second electrode 102 and a third electrode 103 which are stacked in sequence; a micron column array KP is arranged on the surface of the first electrode 101 close to the second electrode 102, and at least one through hole LP is arranged on the first electrode 101; a micron column array KP is arranged on the surface of the second electrode 102 close to the first electrode 101, and at least one through hole LP is arranged on the second electrode 102 (in the figure, due to the obstruction of the micron column array KP, the through hole LP on the second electrode 102 is covered); the third electrode A micron column array KP is arranged on the surface of the electrode 103 on the side close to the second electrode 102, and a groove MP is arranged on the third electrode 103; wherein the material of each micron column in the micron column array KP on each electrode is a composite of SU-8 photoresist and silicon material; a first support member 104 is arranged between the first electrode 101 and the second electrode 102 to isolate the first electrode 101 and the second electrode 102; a second support member 105 is arranged between the second electrode 102 and the third electrode 103 to isolate the second electrode 102 and the third electrode 103.

[0044] Among them, the materials of the first electrode 101, the second electrode 102 and the third electrode 103 can all be silicon materials, and silicon materials are metal nanoporous materials, which not only have a large internal surface area, high porosity and relatively uniform nanopores, but also have excellent properties of metal materials such as corrosion resistance, high conductivity, high thermal conductivity, and fatigue resistance. Therefore, the present application uses metal nanoporous materials to replace carbon nanotube films in traditional sensors, which has better performance.

[0045] The first electrode 101 may be called a cathode, the second electrode may be called an extraction electrode, and the third electrode may be called a collector. The through hole LP on the first electrode 101 and the through hole LP on the second electrode 102 may be circular, and the groove MP on the third electrode 103 may be rectangular.

[0046] The aperture of each through hole LP on the first electrode 101 is greater than or equal to 0.6 mm and less than or equal to 3.6 mm. The aperture of each through hole LP on the second electrode 102 is greater than or equal to 1 mm and less than or equal to 5 mm. The length of the groove MP on the third electrode 103 in the first direction x and the length in the second direction y are both greater than or equal to 1 mm and less than or equal to 8 mm; the length of the groove MP in the third direction z (i.e., the depth of the groove MP) is greater than 100 μm and less than or equal to 240 μm.

[0047] The number of through holes LP on the first electrode 101 is greater than or equal to 1 and less than or equal to 20. The number of through holes LP on the second electrode 102 is greater than or equal to 1 and less than or equal to 20. The number of grooves MP on the third electrode 103 is greater than or equal to 1 and less than or equal to 20.

[0048] When the aperture of each through hole LP on the first electrode 101 is greater than or equal to 0.6 mm and less than or equal to 3.6 mm, the ratio of the spacing between the first electrode 101 and the second electrode 102 to the aperture of the through hole LP on the first electrode 101 is greater than or equal to 1 / 60 and less than or equal to 1 / 8.

[0049] When the aperture of each through hole LP on the second electrode 102 is greater than or equal to 1 mm and less than or equal to 5 mm, the ratio of the spacing between the first electrode 101 and the second electrode 102 to the aperture of the through hole LP on the second electrode 102 is greater than or equal to 9 / 1000 and less than or equal to 2 / 25.

[0050] When the length and width of the groove MP on the third electrode 103 are both greater than or equal to 1 mm and less than or equal to 8 mm, and the depth of the groove MP is greater than 100 μm and less than or equal to 240 μm, the ratio of the distance between the second electrode 102 and the third electrode 103 to the depth of the groove MP is greater than or equal to 3 / 16 and less than or equal to 4 / 5.

[0051] like Figure 2 As shown, a SF 6 Top view of the three electrodes in the decomposition sensor. Figure 2 Figure (a) is a top view of the first electrode 101. Figure 2 Figure (b) is a top view of the second electrode 102. Figure 2 FIG. 5( c ) is a top view of the third electrode 103 .

[0052] In the figure (a), the spacing between the two through holes LP on the first electrode 101 is 0.9 mm, and the diameter of each through hole is 0.3 mm; the length of the micrometer column array KP on the first electrode 101 in the first direction x is 3 mm, and the length in the second direction y is 5 mm; the length of the first electrode 101 in the first direction x is 8 mm, and the length in the second direction y is 7 mm. Other dimensions marked in the figure (a) can be seen in the figure and will not be described in detail here.

[0053] In the figure (b), the distance between the two through holes LP on the second electrode 102 is 0.9 mm, and the diameter of each through hole is 0.3 mm; the length of the micrometer column array KP on the second electrode 102 in the first direction x is 3 mm, and the length in the second direction y is 5 mm; the length of the second electrode 102 in the first direction x is 9 mm, and the length in the second direction y is 7 mm. The other dimensions marked in the figure (b) can be referred to as shown in the figure, and will not be described in detail here. It should be noted that the length of the white area in the first direction x of the figure (b) is 1 mm, which is the length from the edge of the second electrode 102 to the first support member 104.

[0054] In the figure (c), the length of the groove MP on the third electrode 103 in the first direction x is 2.4 mm, and the length in the second direction y is 2 mm; the length of the micrometer column array KP on the third electrode 103 in the first direction x is 3 mm, and the length in the second direction y is 5 mm; the length of the third electrode 103 in the first direction x is 10 mm, and the length in the second direction y is 7 mm. The other dimensions marked in the figure (c) can be referred to as shown in the figure, and will not be described in detail here. It should be noted that the length of the white area in the first direction x of the figure (c) is 2 mm, which is the length from the edge of the third electrode 103 to the second support member 105.

[0055] The material of each micron column in the micron column array KP is a composite of SU-8 photoresist and silicon material, wherein SU-8 photoresist has good corrosion resistance and thermal stability, and combined with silicon material can enhance the field ionization and field-induced electron emission of decomposed products in the field. Moreover, SU-8 photoresist is a flexible material, and in the case of vibration, each micron column in the micron column array KP is not easy to break.

[0056] The diameter of each micro-column in the micro-column array KP is greater than or equal to 5 μm and less than or equal to 10 μm, the height is greater than or equal to 10 μm and less than or equal to 60 μm, and the interval between two adjacent micro-columns is greater than or equal to 10 μm and less than or equal to 30 μm.

[0057] The materials of the first support member 104 and the second support member 105 are both insulating materials. For example, the first support member 104 and the second support member 105 can both be glass.

[0058] The above SF 6 The working principle of the decomposition product sensor is as follows: Under active conditions, SF 6 The decomposition product sensor is in an electric field environment, and the through hole LP on the first electrode 101 is used for SF 6 Decomposition products (such as SO2, H2S, CO) enter, SF 6 The decomposed product is ionized between the first electrode 101 and the second electrode 102. The tip structure of the micron column has a special advantage. Its tip shape can enhance the electric field and realize field emission under a lower electric field. Compared with the traditional planar electrode structure, the operating voltage is reduced, making SF 6 The decomposition sensor can achieve electron emission under a lower electric field. At the same time, there is a larger emission surface area between multiple tips. By increasing the number and layout of tips, the total emission surface area is effectively increased, thereby increasing the emission current density and enhancing the overall current output capacity. The escaped electrons are accelerated by the electric field and interact with the SF 6 After the decomposed molecules collide, more ionization reactions are triggered, generating a large number of positive ions. At this stage, the energy of the electrons continues to increase. The positive ions are bound by the electric field and migrate to the third electrode 103. At this time, the SF can be obtained by measuring the current of the third electrode 103. 6 Decomposition product concentration.

[0059] The above SF 6The decomposition product sensor comprises: a first electrode 101, a second electrode 102 and a third electrode 103 which are stacked in sequence; a micron column array KP is arranged on the surface of the first electrode 101 close to the second electrode 102, and at least one through hole LP is arranged on the first electrode 101; a micron column array KP is arranged on the surface of the second electrode 102 close to the first electrode 101, and at least one through hole LP is arranged on the second electrode 102 (in the figure, due to the obstruction of the micron column array KP, the through hole LP on the second electrode 102 is covered); the third electrode A micron column array KP is arranged on the surface of the first electrode 103 on the side close to the second electrode 102, and a groove MP is arranged on the third electrode 103; wherein the material of each micron column in the micron column array KP on each electrode is a composite of SU-8 photoresist and silicon material; a first support member 104 is arranged between the first electrode 101 and the second electrode 102 to isolate the first electrode 101 and the second electrode 102; a second support member 105 is arranged between the second electrode 102 and the third electrode 103 to isolate the second electrode 102 and the third electrode 103. Compared with a micron column array having only silicon material, the micron column array KP having a composite material of SU-8 photoresist and silicon material can further enhance the electric field effect and promote the occurrence of field emission phenomenon, thereby improving SF 6 Decomposition product sensor for SF 6 The sensitivity and accuracy of the detection of decomposition products. In addition, SU-8 photoresist has the characteristics of flexibility, so in SF 6 When the decomposition product sensor is subjected to vibration, the micron columns in the micron column array KP are not easily broken, thereby avoiding short circuits of the electrodes and thus extending the SF 6 In addition, the micron column array KP is arranged on the second electrode 102, which can increase the reverse electric field range, increase the number of positive ions extracted, thereby increasing the ion flow extracted, and thus reducing the SF 6 The working voltage of the decomposition sensor increases the SF 6 Sensitivity of the decomposition product sensor.

[0060] In one embodiment, continue to refer to Figure 1 and Figure 2 As shown, the orthographic projection of the second electrode 102 on the third electrode covers the orthographic projection of the first electrode 101 on the third electrode 103 ; the orthographic projection of the second electrode 102 on the third electrode 103 covers at least a portion of the third electrode.

[0061] Optionally, in the first direction x, the length of the third electrode 103 is greater than the length of the second electrode 102, and the length of the second electrode 102 is greater than the length of the first electrode 101; in the second direction y, the length of the third electrode 103 is equal to the length of the second electrode 102, and the length of the second electrode 102 is equal to the length of the first electrode 101.

[0062] In one embodiment, continue to refer to Figure 1 and Figure 2 As shown, the micro-pillar array KP on the third electrode 103 is disposed around the groove MP to prevent electrons from overflowing.

[0063] In one embodiment, SF 6 The decomposition product sensor also includes a battery; the first electrode 101 is connected to the negative electrode of the battery; the second electrode 102 is connected to the positive electrode of the battery, so that in the absence of an external power supply, the SF 6 The decomposition product sensor can still be used normally.

[0064] Optional, SF 6 The decomposition product sensor also includes a charging interface for connecting to an external power source to charge the battery.

[0065] In one embodiment, SF 6 The decomposition product sensor also includes a current detector; a first end of the current detector is connected to the third electrode 103, and a second end of the current detector is connected to the second electrode 102, so that the current value can be obtained by detecting the number of electrons from the second electrode 103 to the second electrode 102 through the current detector, and the concentration of the SF6 decomposition product can be obtained based on the current value.

[0066] In one embodiment, SF 6 The decomposition product sensor also includes a housing, which is used to encapsulate the first electrode 101, the second electrode 102 and the third electrode 103. It should be noted that the housing is not completely closed and needs to have an opening to allow the SF 6 The decomposed products enter the region between the first electrode 101 and the second electrode 102 from the through hole LP on the first electrode 101 .

[0067] In one embodiment, SF 6 The decomposition product sensor also includes a pointer arranged on the shell, a concentration etching line arranged on the shell, and a driver and a single-chip microcomputer arranged in the inner cavity of the shell; the single-chip microcomputer is connected to the current detector; one end of the driver is connected to the single-chip microcomputer, and the other end of the driver is connected to the pointer.

[0068] In this embodiment, SF 6The working principle of the decomposition sensor is as follows: the microcontroller receives the current signal sent by the current detector, and the microcontroller sends a drive signal to the driver based on the current signal. The driver rotates the pointer based on the drive signal. The user can read the scale pointed by the value pointer to know the SF 6 Concentration of decomposition products.

[0069] In one embodiment, SF 6 The decomposition product sensor also includes an early warning indicator light, which is connected to the single-chip microcomputer.

[0070] Optional, when SF 6 After the decomposition product sensor is activated, if the single chip microcomputer does not receive the current signal sent by the current detector within the preset time, it sends a first warning signal to the warning indicator light so that the warning indicator light displays the first color. 6 The effect of early warning when a decomposition product sensor fails.

[0071] Optionally, when the current signal sent by the current detector received by the single chip microcomputer exceeds the threshold, a second warning signal is sent to the warning indicator light so that the warning indicator light displays a second color. In this way, SF 6 The effect of early warning when the concentration of decomposition products exceeds the standard.

[0072] Any of the above SF 6 The decomposition sensor can also detect the electric field strength, that is, under active conditions, SF 6 When the decomposition product sensor is in an electric field environment, under the effect of the KP field enhancement of the micron column array, the SF 6 The field ionization and field-induced electron emission of the decomposed products convert the changes of DC electric field, AC electric field and pulse electric field into changes of output current to realize the detection of electric field strength. Among them, the electric field environment includes DC excitation conditions: 50V~500V; pulse excitation conditions: voltage peak value is 50V~500V, frequency range is 10kHz~100kHz, and duty cycle is 1%~100%.

[0073] In one embodiment, Figure 3 As shown, a SF 6 A method for preparing a decomposition product sensor, the method comprising:

[0074] Step 301 : obtaining a first electrode and a second electrode provided with at least one through hole, and obtaining a third electrode provided with a groove.

[0075] The first electrode, the second electrode and the third electrode are all made of silicon.

[0076] Step 302 : using a deep reactive ion etching method based on an alternating reciprocating process to prepare micrometer column arrays on the first electrode, the second electrode, and the third electrode, respectively.

[0077] Among them, for each electrode, in the process of preparing the micron column array, SU-8 photoresist is applied to the surface of the targeted electrode by a spin coating process to form a SU-8 single layer, and the SU-8 single layer is printed using two-photon molding technology. After printing, the uncured SU-8 photoresist is dissolved using ethanol solvent to obtain a micron column array on the surface of the targeted electrode.

[0078] Optionally, control C by setting device parameters of external devices 4 F 8 Etching gas and SF 6 The flow ratio of the protective gas and the etching rate are used to etch each electrode. The equipment parameters include pressure, RF power, source power, C 4 F 8 Etching gas and SF 6 The flow ratio of the protective gas and other related parameters. 4 F 8 Etching gas and SF 6 Under the condition of shielding gas for 2s~15s, the gas pressure of the external device can be set to 6Pa, the RF power to 20W~70W, and the source power to 220W~450W, thus achieving C 4 F 8 Etching gas and SF 6 The flow ratio of the shielding gas is 1.5:1 ~5:1 and the etching rate is 80A / min~400A / min.

[0079] Step 303: Bond a glass sheet between the first electrode and the second electrode to form a first support member, and bond a glass sheet between the second electrode and the third electrode to form a second support member. The thickness of the glass sheet is relatively small, that is, the glass sheet can be a thin glass sheet.

[0080] In addition, each electrode needs a lead, and a gold wire bonding machine can be used to bond the lead to the electrode, and the connection of the lead is completed through the process of playing and automatic lead. The first electrode, the second electrode, and the third electrode also need to be packaged, and the packaging can be ceramic packaging based on the MEMS manufacturing process (Micro Electro Mechanical Systems, MEMS).

[0081] In summary, SF 6The decomposition product sensor has the following advantages: (1) A micron column array KP is arranged on the side of the first electrode 101 close to the second electrode 102, and a micron column array KP is arranged on the surface of the second electrode 102 close to the first electrode 101, forming two opposite micron column arrays KP, which can enhance the influence of the measured electric field on the discharge characteristics of the first electrode 101 (cathode), and structurally constitute a physical structure amplifier for the measured weak electric field, which is different from the passive and active amplifiers in the circuit. The silicon material has a small work function, and the micron column array KP structure has good tip emission characteristics and a large field enhancement factor, which has an amplifying effect on the measured weak electric field, making the SF 6 The decomposition sensor has the ability to detect weak electric fields and has high resolution. The micron column array KP has a stable structure, strong bombardment resistance, and stable performance under strong electric fields, making the sensor have a wide detection range.

[0082] (2) The through hole LP on the first electrode 101, the through hole on the second electrode 102, and the groove on the third electrode 103 are arranged according to the sizes of the through hole LP and the groove MP, so that SF 6 The decomposition sensor can obtain a one-to-one correspondence between the electric field to be measured and the collected current, and can detect the size of the DC electric field, AC electric field and pulse electric field. It has the advantages of wide range, high resolution and high detection accuracy.

[0083] (3) By setting the photoresist for the etching operation in the production of micron pillars, the use of SU-8 photoresist overcomes the problem of insufficient aspect ratio of ordinary photoresist. It is very suitable for the preparation of high aspect ratio microstructures and has good mechanical properties, chemical corrosion resistance and thermal stability, meeting the tolerance requirements of micron pillar materials.

[0084] (4) The micron columns prepared by SU-8 photoresist can form a more favorable electron emission and SF 6 The local electric field environment of the decomposition products ionizes, thereby effectively improving the sensor's sensitivity to SF 6 Detection sensitivity of decomposition products.

[0085] Next, for the above SF 6 The decomposition sensor is tested.

[0086] Embodiment 1: SF 6The first electrode 101 in the decomposition product sensor has 9 through holes LP, and the aperture of the through hole LP on the first electrode 101 is 1.2 mm; the ratio of the spacing between the first electrode 101 and the second electrode 102 to the aperture of the through hole LP on the first electrode 101 is 1 / 16; the central area of ​​the second electrode 102 has 9 through holes LP, and the aperture of the through hole LP on the second electrode 102 is 1.2 mm; the ratio of the spacing between the second electrode 102 and the third electrode 103 to the aperture of the through hole LP on the second electrode 102 is 1 / 16; the first electrode 1 01. The structure of the micron column array KP on the second electrode 102 and the third electrode 103: the distance between two adjacent micron columns is 20 μm, the diameter of each micron column is 10 μm, and the height of each micron column is 60 μm; a groove MP is provided on the third electrode, and the lengths of the groove MP in the first direction x and the second direction y are 6 mm and 8 mm respectively, and the length of the groove MP in the third direction z is 200 μm, and the ratio of the spacing between the second electrode 102 and the third electrode 103 to the length of the groove MP in the third direction z is 15 / 40.

[0087] In this embodiment, the micro-pillar array KP is continuously supplied with SF 6 Shielding gas, C 4 F 8 Under the condition of etching gas 10s, by setting the pressure of external equipment to 6Pa, RF power to 40W, source power to 220W, C 4 F 8 Etching gas and SF 6 The flow ratio of the protective gas is 1.5:1 and the etching rate is 100 A / min.

[0088] SF 6 The decomposition product sensor is in the following electric field environment: (1) DC excitation condition; (2) the voltage of the first electrode 101 is 0V; (3) the voltage of the second electrode 102 is 50V; (4) the voltage of the third electrode is 1V; (5) SF 6 The decomposition temperature is 25℃; (6) SF 6 The decomposition pressure is 100.1 kPa; (7) The distance between two adjacent electrodes is 80 μm~100 μm.

[0089] Using this SF 6 The decomposition product sensors are respectively for SO 2 , H 2 S and CO were tested and obtained Figure 4 SF shown 6 The decomposition product sensor is excited by DC to SO 2 The response characteristic curve of Figure 5 SF shown 6 The decomposition product sensor reacts to H under DC excitation.2 The response characteristic curve of S Figure 6 SF shown 6 Response characteristic curve of decomposition product sensor to CO under DC excitation.

[0090] Depend on Figure 4 It can be seen that in SO 2 When the concentration of SF increases gradually, 6 The response current of the decomposition product sensor gradually decreased, which may be due to the SF 6 SO between electrodes of decomposition product sensor 2 Caused by gas ionization reaction.

[0091] Depend on Figure 5 It can be seen that in H 2 When the concentration of S increases gradually, SF 6 The response current of the decomposition product sensor shows a nonlinear downward trend, that is, it shows negative sensitivity.

[0092] Depend on Figure 6 It can be seen that SF 6 The response current of the decomposition product sensor decreases as the CO concentration increases, showing a nonlinear negative sensitivity characteristic. 6 The response current of the decomposition product sensor changes slowly, but it shows higher sensitivity in the low concentration range, that is, SF 6 Decomposition product sensors have better sensitivity in detecting low concentration gases.

[0093] Embodiment 2: SF 6 The first electrode 101 in the decomposition product sensor has 9 through holes LP, and the aperture of the through holes LP on the first electrode 101 is 0.6 mm; the ratio of the spacing between the first electrode 101 and the second electrode 102 to the aperture of the through holes LP on the first electrode 101 is 1 / 600; the central area of ​​the second electrode 102 has 9 through holes LP, and the aperture of the through holes LP on the second electrode 102 is 0.5 mm; the ratio of the spacing between the second electrode 102 and the third electrode 103 to the aperture of the through holes LP on the second electrode 102 is 1 / 500 ; The structure of the micron column array KP on the first electrode 101, the second electrode 102 and the third electrode 103: the distance between two adjacent micron columns is 10μm, the diameter of each micron column is 5μm, and the height of each micron column is 10μm; a groove MP is provided on the third electrode, the length of the groove MP in the first direction x and the second direction y is 1mm, the length of the groove MP in the third direction z is 100μm, and the ratio of the spacing between the second electrode 102 and the third electrode 103 to the length of the groove MP in the third direction z is 1.

[0094] In this embodiment, the micro-pillar array KP is continuously supplied with SF 6 Shielding gas, C 4 F 8 Under the condition of etching gas 10s, by setting the pressure of external equipment to 6Pa, RF power to 40W, source power to 220W, C 4 F 8 Etching gas and SF 6 The flow ratio of the protective gas is 1.5:1 and the etching rate is 100 A / min.

[0095] SF 6 The decomposition product sensor is in the following electric field environment: (1) pulse excitation condition; (2) voltage peak is 80V; (3) frequency range is 80kHz; (4) pulse width is 50%.

[0096] Using this SF 6 The decomposition product sensors are respectively for SO 2 , H 2 S and CO were tested and obtained Figure 7 SF shown 6 The decomposition product sensor reacts to SO under pulse excitation 2 The response characteristic curve of Figure 8 SF shown 6 The decomposition product sensor reacts to H under pulse excitation. 2 The response characteristic curve of S Fig. 9 SF shown 6 Response characteristic curve of the decomposition product sensor to CO under pulse excitation.

[0097] Depend on Figure 7 It can be seen that when pulse power supply is used, SF 6 Decomposition product sensors for different SO 2 The response current value of the concentration point gradually decreases and shows a nonlinear single-valued decreasing relationship. This response trend is consistent with the response under DC excitation.

[0098] Depend on Figure 8 It can be seen that with the increase of H 2 The increase of S concentration, SF 6 The response current of the decomposition product sensor decreases, showing a nonlinear single-value decrease relationship, and its response trend is also consistent with that under DC excitation. In the measurement of 0ppm-100ppm concentration range, SF 6 The response current of the decomposition product sensor decreases significantly, while in the concentration range of 100ppm-500ppm, the sensor's current decreases more gently.

[0099] Depend on Fig. 9 It can be seen that SF 6The response current of the decomposition product sensor decreases as the CO concentration increases. After multiple measurements, it is found that when SF 6 When the decomposition product sensor is powered by pulse, SF 6 The output response value of the decomposition product sensor is larger and the current variation range is wider, that is, compared with the DC working mode, the sensor output range and sensitivity under pulse excitation are improved.

[0100] Example 3: SF 6 The first electrode 101 in the decomposition product sensor has 9 through holes LP, and the aperture of the through hole LP on the first electrode 101 is 1.2 mm; the ratio of the spacing between the first electrode 101 and the second electrode 102 to the aperture of the through hole LP on the first electrode 101 is 1 / 12; the central area of ​​the second electrode 102 has 9 through holes LP, and the aperture of the through hole LP on the second electrode 102 is 1.2 mm; the ratio of the spacing between the second electrode 102 and the third electrode 103 to the aperture of the through hole LP on the second electrode 102 is 1 / 12; The structure of the micron column array KP on the electrode 101, the second electrode 102 and the third electrode 103 is as follows: the distance between two adjacent micron columns is 15 μm, the diameter of each micron column is 8 μm, and the height of each micron column is 40 μm; a groove MP is provided on the third electrode, the length of the groove MP in the first direction x and the second direction y are both 0.5 mm, the length of the groove MP in the third direction z is 200 μm, and the ratio of the spacing between the second electrode 102 and the third electrode 103 to the length of the groove MP in the third direction z is 1 / 2.

[0101] In this embodiment, the micro-pillar array KP is continuously supplied with SF 6 Shielding gas, C 4 F 8 Under the condition of etching gas 10s, by setting the pressure of external equipment to 6Pa, RF power to 40W, source power to 220W, C 4 F 8 Etching gas and SF 6 The flow ratio of the protective gas is 1.5:1 and the etching rate is 100 A / min.

[0102] SF 6 The decomposition product sensor is in the following electric field environment: (1) pulse excitation condition; (2) voltage peak is 80V; (3) frequency range is 80kHz; (4) pulse width is 50%.

[0103] Using this SF 6 The decomposition product sensors are respectively for SO 2 , H 2 S and CO were tested and obtained Fig.10 SF shown 6The decomposition product sensor reacts to SO under pulse excitation 2 The response characteristic curve of Fig.11 SF shown 6 The decomposition product sensor reacts to H under pulse excitation. 2 The response characteristic curve of S Fig.12 SF shown 6 Response characteristic curve of the decomposition product sensor to CO under pulse excitation.

[0104] Fig.10 , Fig.11 and Fig.12 Respectively Figure 7 , Figure 8 and Fig. 9 The characteristics of the display are related, so I will not go into details here. What needs to be explained is that Figure 4-Figure 12 The middle collector refers to the third electrode 103 .

[0105] SF of this application 6 The comparison between the decomposition product sensor and the sensor in the prior art is shown in Table 1.

[0106] Table 1

[0107]

[0108] The above SF 6 The calculation formula of the sensitivity of the decomposition product sensor is: ,in, For different SF 6 Decomposition product concentration point number, ; For SF 6 an average value of the response current of the third electrode of the decomposition product sensor; For SF 6 Decomposition product concentration value.

[0109] Normalized sensitivity =SF 6 Decomposition product sensor sensitivity SF 6 Decomposition product sensor output range;

[0110] SF 6 Decomposition product sensor output range = maximum response current - minimum response current.

[0111] The above SF 6 Compared with the performance indicators of existing related sensors, the performance of the decomposition product sensor in terms of detection range is superior, which is about one order of magnitude higher than that of existing related sensors. 6The decomposition sensor is based on MEMS technology and has a volume of only 7mm×11mm×2mm. 6 Decomposition product sensors have more advantages in miniaturization and have very good application prospects.

[0112] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0113] It should be noted that, unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present application. The terms used herein in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0114] It is understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0115] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0116] It can be understood that “at least one” means one or more, “plurality” means two or more, and “at least a portion of an element” means a part or all of an element.

[0117] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0118] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0119] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A SF6 decomposition product sensor, characterized in that: The SF6 decomposition product sensor comprises a first electrode, a second electrode and a third electrode which are stacked in sequence; A micron column array is arranged on the surface of the first electrode close to the second electrode, and at least one through hole is arranged on the first electrode; a micron column array is arranged on the surface of the second electrode close to the first electrode, and at least one through hole is arranged on the second electrode; a micron column array is arranged on the surface of the third electrode close to the second electrode, and a groove is arranged on the third electrode; wherein the material of each micron column in the micron column array on each electrode is a composite of SU-8 photoresist and silicon material; A first support member is disposed between the first electrode and the second electrode to isolate the first electrode from the second electrode; and a second support member is disposed between the second electrode and the third electrode to isolate the second electrode from the third electrode.

2. The SF6 decomposition product sensor according to claim 1, characterized in that: The orthographic projection of the second electrode on the third electrode covers the orthographic projection of the first electrode on the third electrode; The orthographic projection of the second electrode on the third electrode covers at least a portion of the third electrode.

3. The SF6 decomposition product sensor according to claim 1, characterized in that: The micrometer column array on the third electrode is arranged around the groove.

4. The SF6 decomposition product sensor according to claim 1, characterized in that: The SF6 decomposition product sensor also includes a battery; The first electrode is connected to the negative electrode of the battery; the second electrode is connected to the positive electrode of the battery.

5. The SF6 decomposition product sensor according to claim 1, characterized in that: The SF6 decomposition product sensor also includes a current detector; A first terminal of the current detector is connected to the third electrode, and a second terminal of the current detector is connected to the second electrode.

6. The SF6 decomposition product sensor according to claim 5, characterized in that: The SF6 decomposition product sensor further includes a shell, and the shell is used to encapsulate the first electrode, the second electrode and the third electrode.

7. The SF6 decomposition product sensor according to claim 6, characterized in that: The SF6 decomposition product sensor also includes a pointer arranged on the shell, a concentration etching line arranged on the shell, and a driver and a single chip microcomputer arranged in the inner cavity of the shell; The single chip microcomputer is connected to the current detector; One end of the driver is connected to the single chip microcomputer, and the other end of the driver is connected to the pointer.

8. The SF6 decomposition product sensor according to claim 7, characterized in that: The SF6 decomposition product sensor also includes an early warning indicator light, and the early warning indicator light is connected to the single chip microcomputer.

9. The SF6 decomposition product sensor according to claim 4, characterized in that: The SF6 decomposition product sensor also includes a charging interface for connecting to an external power source to charge the battery.

10. A method for preparing a SF6 decomposition product sensor, characterized in that: The method comprises: Obtain a first electrode and a second electrode provided with at least one through hole, and obtain a third electrode provided with a groove; wherein the materials of the first electrode, the second electrode and the third electrode are all silicon materials; A deep reactive ion etching method based on an alternating reciprocating process is used to prepare micrometer column arrays on the first electrode, the second electrode and the third electrode, respectively. For each electrode, in the process of preparing the micrometer column array, SU-8 photoresist is applied on the surface of the electrode to form a SU-8 single layer by a spin coating process, and the SU-8 single layer is printed by a two-photon molding technology. After the printing is completed, an ethanol solvent is used to dissolve the uncured SU-8 photoresist to obtain a micrometer column array on the surface of the electrode; A glass sheet is bonded between the first electrode and the second electrode to form a first support member, and a glass sheet is bonded between the second electrode and the third electrode to form a second support member.

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