Integrated high-temperature-resistant lead-bismuth-resistant pressure sensor and working method thereof

Abstract

The invention relates to an integrated high-temperature-resistant lead-bismuth-resistant pressure sensor and a working method thereof, and belongs to the field of sensors, the integrated high-temperature-resistant lead-bismuth-resistant pressure sensor comprises a sensor main body and a cable output device, and the sensor main body and the cable output device are connected through a metal cable; the upper end of the cable shell is connected with the metal cable, the lower end of the cable shell is sequentially welded with the shell, the diaphragm and the threaded column with the hole to form an integrated shell structure, the graphene column is arranged in the integrated shell structure, and the upper end of the graphene column is connected with a core wire of the metal cable; the insulating tube is located in the integrated shell structure and wraps the graphene column, the lower end of the graphene column is connected with the piezoelectric ceramic and the metal gasket, the piezoelectric ceramic is completely located in the insulating tube, the metal gasket is partially located in the insulating tube, and the bottom of the metal gasket is embedded above the diaphragm; insulating rings are arranged at the contact position of the graphene column and the cable shell and the contact position of the graphene column and the shell. According to the invention, short circuit or open circuit is not easy to occur, sealing performance and performance are good, and normal operation can be continuously carried out in a high-temperature lead-bismuth environment.

Description

Technical Field

[0001] The invention relates to an integrated high-temperature-resistant and lead-resistant bismuth pressure sensor and a working method thereof, belonging to the technical field of sensors. Background Art

[0002] Piezoelectric pressure sensor is a commonly used type of pressure sensor. It uses piezoelectric material as a sensitive element. Under the action of external force, equal and opposite charges are generated on the two surfaces of the piezoelectric material. The amount of charge is proportional to the magnitude of the applied external force. Piezoelectric pressure sensor has the characteristics of high sensitivity, good linearity and high frequency response. It is mainly used for dynamic pressure measurement, such as turbulence, explosion, ballistics, engine combustion and pressure measurement in pulse wind tunnels. Traditional piezoelectric pressure sensors often use high-temperature wires to connect to piezoelectric materials, but this method is prone to solder joints falling off in environments such as explosions and vibrations, which can cause the sensor to short or open circuit; traditional piezoelectric pressure sensors have poor sealing properties. In some harsh high-temperature measurement environments, such as combustion fields, the presence of dust, water vapor and other products in the measurement environment can easily affect the measurement results of the piezoelectric pressure sensor; in addition, the diaphragm of the traditional piezoelectric pressure sensor is an ordinary flat diaphragm, and the performance of the flat diaphragm is poor; the installation conditions of traditional piezoelectric pressure sensors are single and cannot meet the installation and use of multiple scenarios, and further sensor installation methods need to be added; traditional piezoelectric pressure sensors cannot continue to work normally in a high-temperature lead-bismuth environment, which leads to significant changes in the sensitivity, linearity and other parameters of the sensor. Therefore, the lead-bismuth resistance of the piezoelectric pressure sensor also needs to be further improved. Summary of the invention

[0003] In view of the shortcomings of the prior art that sensors are prone to short circuit or open circuit, have poor sealing, poor performance, single installation conditions, and cannot continue to work normally in a high-temperature lead-bismuth environment, the present invention provides an integrated high-temperature resistant lead-bismuth pressure sensor and a working method thereof.

[0004] The present invention adopts the following technical solutions:

[0005] On the one hand, the present invention provides an integrated high temperature resistant and lead resistant bismuth pressure sensor, comprising a sensor body and a cable output device, wherein the sensor body and the cable output device are connected by a metal cable; the sensor body comprises a cable shell, an outer shell, an insulating tube, a graphene column, a piezoelectric ceramic, a metal gasket, a diaphragm and a threaded column with a hole;

[0006] The metal cable is a solid cylindrical structure containing a single core wire. The upper end of the cable shell is connected to the metal cable. The lower end of the cable shell is welded to the outer shell, the diaphragm and the threaded column with holes in sequence to form an integrated shell structure. The graphene column is arranged inside the integrated shell structure, and the upper end is connected to the core wire of the metal cable. The insulating tube is located inside the integrated shell structure and wrapped around the outside of the graphene column. The lower end of the graphene column is connected to the piezoelectric ceramic and the metal gasket. The piezoelectric ceramic is completely located inside the insulating tube, the metal gasket is partially located inside the insulating tube, and the bottom of the metal gasket is embedded above the diaphragm.

[0007] Insulating rings are provided at the contact points between the graphene column and the cable shell, and at the contact points between the graphene column and the outer shell. The insulating rings are circular ring structures, which can not only support the cable shell, but also form an insulating layer to prevent the cable shell from contacting the graphene column.

[0008] Preferably, the upper end of the cable shell is a cylindrical conical structure with a φ3.2 through hole in the middle, through which the metal cable is inserted, and the contact between the upper end of the cable shell and the metal cable is connected and fixed by welding and sintering, and further sintered after welding, so as to prevent the metal cable from shaking and improve the strength;

[0009] The cable shell, outer shell, diaphragm and threaded column with holes are all made of 316L stainless steel.

[0010] The sensor of the present invention adopts a brand-new core structure, which is an integrated conductive structure, and the exterior is made of 316L stainless steel and is sealed by laser welding.

[0011] Preferably, the inner surface of the shell is polished to present a smooth surface, which helps to reduce convective heat transfer and radiative heat transfer. The lower part of the outer side of the shell is an M10 threaded structure, and the upper part is a hexagonal nut structure, which is convenient for detection and installation of the sensor.

[0012] Preferably, the lower end of the graphene column is a cylindrical entity, the upper end is provided with a boss, the center of the boss is provided with a concave circular hole, the aperture of the concave circular hole is the same as the outer diameter of the core wire of the metal cable, and the core wire of the metal cable can be directly embedded into the concave circular hole of the graphene column to achieve fixation, thereby transmitting the obtained information to the external cable. The graphene column has high hardness and strength, good electrical conductivity, and high temperature tolerance. Using graphene with good electrical conductivity as a conductor not only plays a supporting role, but also improves the stability of the sensor at high temperature, avoiding the risk of short circuit or open circuit caused by bumps.

[0013] In the present invention, the insulating tube is a cylindrical structure, in which a graphene column can be inserted, and piezoelectric ceramics and metal gaskets can be placed. On the one hand, the concentricity of the graphene column, piezoelectric ceramics and metal gaskets is ensured, and on the other hand, the insulation performance can be ensured, and it has a strong insulation and supporting effect.

[0014] Piezoelectric ceramics are solid cylindrical structures with excellent compressive strength and monitoring performance.

[0015] The metal gasket is a thin solid cylindrical structure that can provide planar support for the piezoelectric ceramic.

[0016] Preferably, the upper and lower ends of the diaphragm are both concave structures, which are helpful for pressure distribution. A fixing groove A is provided on the edge of the upper end for fixed connection with the outer shell, and a step groove is provided in the middle of the upper end for installing metal gaskets and insulating tubes; a fixing groove B is provided at the lower end of the diaphragm, and the fixing groove B is used for installing a threaded column with a hole. An inward-concave hemisphere A is provided in the middle of the fixing groove B.

[0017] Preferably, the threaded column with a hole is a cylindrical structure, and a concave hemisphere B is provided at its upper end. After installation, hemisphere A and hemisphere B constitute the entire spherical space. The outer side of the threaded column with a hole is an M5 thread structure, and a concave arc groove is provided at the lower end of the threaded column with a hole, and a channel is provided between the concave arc groove and the concave hemisphere B.

[0018] The spherical space principle of the present invention is similar to that of a spherical pressure vessel. Due to the shape characteristics of the sphere, the distance from each point on its surface to the center of the sphere is equal. When liquid or gas is stored in the sphere, the internal pressure will be evenly distributed on the entire spherical surface. This uniform pressure distribution makes the stress borne by the material of the spherical structure more uniform when it is subjected to the same pressure, which is beneficial to the pressure distribution. The outer side of the lower end of the threaded column with holes is an M5 thread structure, which is convenient for installation, and the inner side of the lower end is a concave arc structure, similar to a gently sloping funnel structure, which is convenient for concentrating pressure in the through-hole structure with a narrower center, and then the measured pressure is buffered to the overall spherical structure for distribution.

[0019] Preferably, the cable output device comprises a rear housing, a front housing, a filter amplifier circuit, a built-in nozzle and a tin foil sleeve;

[0020] One end of the rear shell is a conical cylindrical structure, and the other end is a cylindrical structure. The front shell is a cylindrical structure. The rear shell and the front shell are welded to form a shell structure. The metal cable penetrates into the rear shell from one end of the conical cylindrical structure and is connected and fixed by welding and sintering. A tin foil sleeve is fixedly arranged inside the rear shell, and a rectangular filter amplifier circuit is placed in the tin foil sleeve. The filter amplifier circuit has an amplification factor of 1 and has a filtering function, which can maximize the output accuracy and reduce external interference. The core wire of the metal cable is connected to the input end of the filter amplifier circuit, and the output end of the filter amplifier circuit is connected to the built-in nozzle.

[0021] Preferably, the built-in nozzle comprises an integrally formed cylinder A and cylinder B, the diameter of cylinder B is larger than that of cylinder A, cylinder B is fixedly connected to the front housing, two transmission holes are arranged in the middle of the built-in nozzle, the inner wall of the transmission hole is coated with a metal conductive layer, two copper protrusions are arranged above cylinder B of the built-in nozzle, and the two copper protrusions are respectively connected to the two transmission holes; the output end of the filter amplifier circuit is connected to the two copper protrusions for connecting to the outside and outputting signals;

[0022] The built-in nozzle is made of polytetrafluoroethylene.

[0023] Preferably, the sensor assembly process is as follows:

[0024] (1) placing an insulating ring into the upper inner end of the housing and fitting it tightly; placing a graphene column into the housing until the graphene column fits the insulating ring;

[0025] (2) putting an insulating tube on the outside of the graphene column and fitting it with the graphene column; putting the piezoelectric ceramic into the insulating tube and fitting it with the graphene column, and putting the metal gasket into the insulating tube and fitting it with the bottom of the piezoelectric ceramic;

[0026] (3) Fit the diaphragm to the lower end of the housing, and fit the inner side of the diaphragm to the insulating tube and the metal gasket, and press and weld them together;

[0027] (4) Fit the threaded column with holes into the lower end of the diaphragm, press and weld them to fix;

[0028] (5) Pass one end of the metal cable through the cable shell, insert the core wire of the metal cable into the concave circular hole of the graphene column and fix it, and weld and sinter the junction between the upper end of the cable shell and the metal cable;

[0029] (6) Lead out the core wire of the other end of the metal cable, insert the metal cable from the conical cylindrical structure end of the rear shell into the rear shell, weld and sinter to fix it, place the tin foil sleeve inside the rear shell and fix it, place the filter amplifier circuit inside the tin foil sleeve, and connect the input end of the filter amplifier circuit to the core wire of the metal cable; fill 704 silicone rubber in the rear shell containing the filter amplifier circuit to fix the filter amplifier circuit, fix the output end of the filter amplifier circuit to the two copper protrusions of the built-in connector by soldering, apply high-temperature curing glue on the surface, insert the built-in connector into the front shell and fix it, finally dock the rear shell with the front shell and fix them by welding at the gap to improve the mechanical strength and increase the service life, and the signal is finally output from the two transmission holes of the built-in connector.

[0030] The filter amplifier circuit can adopt an existing structure, such as the IE174130 filter amplifier circuit.

[0031] On the other hand, the present invention provides a working method based on the above-mentioned integrated high temperature resistant lead resistant bismuth pressure sensor, comprising the following process:

[0032] The sensor is fixed, and there are water pressure, oil pressure, air pressure, lead, bismuth and other media around it. The sensor is first compressed by the bottom of the threaded column with a hole. The medium is concentrated into the channel through the concave arc groove at the bottom of the threaded column with a hole. The pressure is buffered to a certain extent through the narrow channel structure. Finally, the pressure is gathered in the spherical space composed of hemisphere A and hemisphere B. The pressure generated by this type of medium causes the pressure structure of the sensor to deform. Since the arc surface structure of the spherical space makes the pressure uniform, the diaphragm of the sensor is deformed at this time. The metal gasket is subjected to strain and squeezes the piezoelectric ceramic. When the piezoelectric ceramic is subjected to an external force in a fixed direction, the internal Polarization phenomenon is generated, and charges with opposite signs are generated on the two surfaces at the same time. After the charges are generated, the graphene column transmits the signal and inputs it into the filter amplifier circuit of the cable output device through the metal cable. Then, the charge signal is converted into a voltage signal by the filter amplifier circuit, and is transmitted through the built-in nozzle after filtering. Finally, the signal is recorded by the data collector. When the sensor is installed, the sensor can be installed and fixed by the M10 threaded structure on the outer side of the upper shell of the sensor, or by the M5 threaded structure or thread on the outer side of the threaded column with holes at the bottom of the sensor. The applicable scenarios can involve the installation and use scenarios of M5 and M10 respectively.

[0033] The pressure P is obtained by the following formula:

[0034]

[0035] Wherein, Q represents the charge, k is the piezoelectric constant of the piezoelectric ceramic, and S is the contact area between the piezoelectric ceramic and the graphene column.

[0036] Where the present invention is not exhaustive, prior art may be used.

[0037] The beneficial effects of the present invention are:

[0038] 1. Compared with the traditional wire structure, the internal conductive structure of the sensor of the present invention uses a graphene column structure with high hardness, good conductivity and high temperature resistance. The upper end of the graphene column structure has a concave circular hole, which can fix the core wire of the cable and directly conduct it. It can be directly installed during the assembly process, avoiding the risk of short circuit or open circuit caused by bumps in conventional structures; the upper end of the graphene column structure is a solid cylindrical structure, which can be used to provide support, and can be directly installed concentrically with an insulating ring to avoid uneven force; the lower end of the graphene column structure is also a solid cylindrical structure, with a flat bottom, directly connected to the piezoelectric ceramic of the same size, and the force is uniform, which improves the stability of the sensor at high temperature. In addition, graphene has good thermal stability and can withstand a relatively stable temperature of about 600°C, and the extreme high temperature can reach more than 4000°C. Using a graphene column with good conductivity as a connecting column with piezoelectric ceramics not only plays a supporting role, but also is expected to further improve the high temperature resistance of the sensor.

[0039] 2. The upper and lower ends of the diaphragm of the sensor of the present invention are both concave structures. The concave structure at the upper end is used to fix internal parts, and the lower end is provided with a concave hemisphere A, which can be welded with a threaded column with a hole to form a spherical space, which is helpful for pressure distribution, can enable the sensor to obtain better impact resistance, help to improve the measurement sensitivity, and can effectively improve the accuracy and linearity of the sensor.

[0040] 3. The present invention is provided with a filter amplifier circuit, and the filter amplifier circuit is placed inside the tin foil sleeve, which can shield interference signals and increase output accuracy and output stability.

[0041] 4. The sensor of the present invention uses high temperature resistant and corrosion resistant 316L stainless steel as the shell, which has the performance of high temperature resistance and lead-bismuth resistance. It can withstand a high temperature of 500°C in a high temperature lead-bismuth environment, which greatly improves the durability and stability of the sensor in a high temperature lead-bismuth environment. In addition, the inner surface of the shell is polished to reduce convective heat transfer and radiation heat transfer. On this basis, the sensor is vacuum welded during the welding process to ensure airtight welding so that a vacuum cavity is formed inside the shell, thereby avoiding penetration defects. The existence of the vacuum cavity can effectively insulate, thereby further improving the performance of the sensor in a high temperature environment.

[0042] 5. The sensor of the present invention adopts two installation methods. It can be installed and fixed by the M10 thread structure on the outside of the upper shell of the sensor, or by the M5 thread structure or thread on the outside of the threaded column with a hole at the bottom of the sensor. The applicable scenarios can involve the installation and use scenarios of M5 and M10 respectively, which increases the installation applicability of the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1It is a schematic cross-sectional structure diagram of the integrated high temperature resistant and lead resistant bismuth pressure sensor of the present invention;

[0044] Figure 2 It is a schematic diagram of the three-dimensional structure of the integrated high temperature resistant and lead resistant bismuth pressure sensor of the present invention;

[0045] Figure 3 It is an assembly explosion diagram of the integrated high temperature resistant and lead resistant bismuth pressure sensor of the present invention;

[0046] Figure 4 It is a schematic cross-sectional structure diagram of the cable output device of the present invention;

[0047] Figure 5 It is a schematic diagram of the three-dimensional structure of the cable output device of the present invention;

[0048] Figure 6 It is an exploded view of the assembly of the cable output device of the present invention;

[0049] Figure 7 It is a schematic diagram of the cable housing structure of the present invention;

[0050] Figure 8 It is a schematic diagram of the shell structure of the present invention;

[0051] Fig. 9 It is a three-dimensional diagram of the diaphragm structure of the present invention;

[0052] Fig.10 is a schematic diagram of the cross-sectional structure of the diaphragm of the present invention;

[0053] Fig.11 It is a schematic diagram of the graphene column structure of the present invention;

[0054] Fig.12 It is a schematic diagram of the structure of a threaded column with a hole of the present invention;

[0055] Fig.13 It is a schematic diagram of the cross-sectional structure of the threaded column with a hole of the present invention;

[0056] Fig.14 It is a schematic diagram of a frequency response curve of the present invention;

[0057] In the figure, 1-metal cable, 2-cable shell, 3-insulating ring, 4-shell, 5-insulating tube, 6-graphene column, 7-diaphragm, 8-threaded column with hole, 9-metal gasket, 10-piezoelectric ceramic, 11-rear shell, 12-filter amplifier circuit, 13-front shell, 14-built-in nozzle, 15-tin foil sleeve, 16-704 silicone rubber, 17-boss, 18-fixing groove A, 19-step groove, 20-fixing groove B, 21-hemispherical body A, 22-hemispherical body B, 23-concave arc groove, 24-column A, 25-column B, 26-transmission hole, 27-copper protrusion. DETAILED DESCRIPTION

[0058] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, they will be described in detail with reference to the accompanying drawings and specific embodiments, but are not limited to these. Anything not fully described in the present invention shall be based on conventional techniques in the art.

[0059] In the description of the present invention, it should be noted that the terms "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0060] Example 1

[0061] An integrated high temperature and lead resistant bismuth pressure sensor, such as Figures 1 to 13 As shown, it includes a sensor body and a cable output device, and the sensor body and the cable output device are connected by a metal cable 1; the sensor body includes a cable shell 2, an insulating ring 3, a housing 4, an insulating tube 5, a graphene column 6, a piezoelectric ceramic 10, a metal gasket 9, a diaphragm 7 and a threaded column with a hole 8;

[0062] The metal cable 1 is a solid cylindrical structure, containing a single core wire. The upper end of the cable shell 2 is connected to the metal cable 1, and the lower end of the cable shell 2 is welded to the outer shell 4, the diaphragm 7 and the threaded column 8 with holes in sequence to form an integrated shell structure. The graphene column 6 is arranged inside the integrated shell structure, and the upper end is connected to the core wire of the metal cable 1; the insulating tube 5 is located inside the integrated shell structure and wrapped around the outside of the graphene column 6, and the lower end of the graphene column 6 is connected to the piezoelectric ceramic 10 and the metal gasket 9, the piezoelectric ceramic 10 is completely located inside the insulating tube 5, the metal gasket 9 is partially located inside the insulating tube 5, and the bottom of the metal gasket 9 is embedded above the diaphragm 7;

[0063] Insulating rings 3 are provided at the contact points between the graphene column 6 and the cable housing 2, and at the contact points between the graphene column 6 and the housing 4. The insulating ring 3 is a circular ring structure, which can not only support the cable housing, but also form an insulating layer to prevent the cable housing from contacting the graphene column.

[0064] Example 2

[0065] An integrated high temperature resistant lead resistant bismuth pressure sensor, as described in Example 1, except that the upper end of the cable shell 2 is a cylindrical conical structure with a φ3.2 through hole in the middle, the metal cable 1 is inserted through the through hole, and the upper end of the cable shell 2 and the metal cable 1 are connected and fixed by welding and sintering at the contact point, and further sintered after welding, so as to prevent the metal cable from shaking and improve the strength;

[0066] The cable housing 2, the outer housing 4, the diaphragm 7 and the threaded column with holes 8 are all made of 316L stainless steel.

[0067] The sensor of the present invention adopts a brand-new core structure, which is an integrated conductive structure, and the exterior is made of 316L stainless steel and is sealed by laser welding.

[0068] The inner surface of the shell 4 is polished to present a smooth surface, which helps to reduce convection heat transfer and radiation heat transfer. The lower part of the outer side of the shell 4 is an M10 thread structure, and the upper part is a hexagonal nut structure, which is convenient for the detection and installation of the sensor.

[0069] The lower end of the graphene column 6 is a cylindrical entity, and a boss 17 is provided at the upper end. A concave circular hole is provided at the center of the boss 17. The aperture of the concave circular hole is the same as the outer diameter of the core wire of the metal cable. The core wire of the metal cable 1 can be directly embedded into the concave circular hole of the graphene column 6 to achieve fixation, thereby transmitting the obtained information to the external cable, such as Fig.11 As shown. The graphene column 6 has high hardness, good electrical conductivity and high temperature resistance. Using graphene with good electrical conductivity as a conductor not only plays a supporting role, but also improves the stability of the sensor at high temperatures and avoids the risk of short circuit or open circuit caused by bumps.

[0070] In the present invention, the insulating tube 5 is a cylindrical structure, in which the graphene column 6 can be inserted, and the piezoelectric ceramic 10 and the metal gasket 9 are placed. On the one hand, the concentricity of the graphene column 6, the piezoelectric ceramic 10 and the metal gasket 9 is ensured, and on the other hand, the insulation performance can be ensured, and it has a strong insulation and supporting effect.

[0071] The piezoelectric ceramic 10 is a solid cylindrical structure and has excellent compressive strength and monitoring performance.

[0072] The metal gasket 9 is a thin solid cylindrical structure, which can provide planar support for the piezoelectric ceramics.

[0073] Example 3

[0074] An integrated high-temperature resistant and lead-resistant bismuth pressure sensor, as described in Example 2, except that the upper and lower ends of the diaphragm 7 are both concave structures, which are helpful for pressure distribution, and a fixing groove A 18 is provided at the edge of the upper end for fixed connection with the housing 4, and a stepped groove 19 is provided in the middle of the upper end for installation of the metal gasket 9, the piezoelectric ceramic 10 and the insulating tube 5; a fixing groove B 20 is provided at the lower end of the diaphragm 7, and the fixing groove B 20 is used for installation of the threaded column 8 with a hole, and a concave hemisphere A 21 is provided in the middle of the fixing groove B 20, as shown in FIG. Fig.10 shown.

[0075] The threaded column with a hole 8 is a cylindrical structure, and a concave hemispherical body B 22 is arranged at its upper end. After installation, the hemispherical body A21 and the hemispherical body B 22 constitute the entire spherical space. The outer side of the threaded column with a hole 8 is an M5 thread structure. The lower end of the threaded column with a hole 8 is provided with a concave arc groove 23. A channel is provided between the concave arc groove 23 and the concave hemispherical body B 22, such as Fig.12 and Fig.13 shown.

[0076] The spherical space principle of the present invention is similar to that of a spherical pressure vessel. Due to the shape characteristics of the sphere, the distance from each point on its surface to the center of the sphere is equal. When liquid or gas is stored in the sphere, the internal pressure will be evenly distributed on the entire spherical surface. This uniform pressure distribution makes the stress borne by the material of the spherical structure more uniform when it is subjected to the same pressure, which is beneficial to the pressure distribution. The outer side of the lower end of the threaded column with holes is an M5 thread structure, which is convenient for installation, and the inner side of the lower end is a concave arc structure, similar to a gently sloping funnel structure, which is convenient for concentrating pressure in the through-hole structure with a narrower center, and then the measured pressure is buffered to the overall spherical structure for distribution.

[0077] Example 4

[0078] An integrated high temperature resistant lead resistant bismuth pressure sensor, as described in Example 3, except that Figure 4 As shown, the cable output device includes a rear housing 11, a front housing 13, a filter amplifier circuit 12, a built-in nozzle 14 and a tin foil sleeve 15;

[0079] One end of the rear shell 11 is a conical cylindrical structure, and the other end is a cylindrical structure. The front shell 13 is a cylindrical structure. The rear shell 11 and the front shell 13 are welded to form a shell structure. The metal cable penetrates into the rear shell from one end of the conical cylindrical structure and is connected and fixed by welding and sintering. A tin foil sleeve 15 is fixedly arranged inside the rear shell 11, and a rectangular filter amplifier circuit 12 is placed in the tin foil sleeve 15. The filter amplifier circuit 12 is an IE174130 model with an amplification factor of 1. It has a filtering function, can maximize the output accuracy, and reduce external interference. The core wire of the metal cable 1 is connected to the input end of the filter amplifier circuit 12, and the output end of the filter amplifier circuit 12 is connected to the built-in nozzle 14.

[0080] like Figure 6As shown, the built-in nozzle 14 includes an integrally formed column A24 and a column B25, the diameter of the column B25 is larger than that of the column A24, the column B25 is fixedly connected to the front housing 13, two transmission holes 26 are arranged in the middle of the built-in nozzle 14, the inner wall of the transmission hole 26 is coated with a metal conductive layer, and two copper protrusions 27 are arranged above the column B25 of the built-in nozzle 14, and the two copper protrusions 27 are respectively connected to the two transmission holes 26; the output end of the filter amplifier circuit 12 is connected to the two copper protrusions 27 for connecting to the outside and outputting signals;

[0081] The built-in nozzle 14 is made of polytetrafluoroethylene.

[0082] Example 5

[0083] An integrated high temperature resistant lead resistant bismuth pressure sensor, as described in Example 4, except that the assembly process of the sensor is as follows:

[0084] (1) placing an insulating ring 3 into the upper inner end of the housing 4 and fitting it tightly; placing a graphene column 6 into the housing 4 until the graphene column 6 fits the insulating ring 3;

[0085] (2) The insulating tube 5 is placed on the outside of the graphene column 6 and is embedded with the graphene column 6; the piezoelectric ceramic 10 is placed inside the insulating tube 5 and is fitted with the bottom of the graphene column 6; the metal gasket 9 is placed inside the insulating tube and is fitted with the bottom of the piezoelectric ceramic 10;

[0086] (3) The diaphragm 7 is fitted into the lower end of the housing 4, and the inner side of the diaphragm 7 is fitted into the insulating tube 6 and the metal gasket 9, and they are pressed and welded to fix;

[0087] (4) Fit the threaded column 8 with holes into the lower end of the diaphragm 7, press them tightly and weld them to fix;

[0088] (5) Pass one end of the metal cable 1 through the cable housing 2, insert the core wire of the metal cable 1 into the concave circular hole of the graphene column 6 and fix it, and weld and sinter the junction between the upper end of the cable housing 2 and the metal cable 1;

[0089] (6) Lead out the core wire of the other end of the metal cable 1, insert the metal cable 1 from the conical cylindrical structure end of the rear shell into the rear shell 11, and then weld and sinter to fix it. Place the tin foil sleeve 15 inside the rear shell 11 and fix it. Place the filter amplifier circuit 12 inside the tin foil sleeve 15, and connect the input end of the filter amplifier circuit 12 to the core wire of the metal cable 1; fill the rear shell containing the filter amplifier circuit with 704 silicone rubber 16 to fix the filter amplifier circuit 12, fix the output end of the filter amplifier circuit 12 to the two copper protrusions 27 of the built-in connector with solder, and apply high-temperature curing glue on the surface, insert the built-in connector 14 into the front shell 13 and fix it. Finally, dock the rear shell 11 with the front shell 13 and fix them by welding at the gap to improve the mechanical strength and increase the service life. The signal is finally output from the two transmission holes of the built-in connector.

[0090] Example 6

[0091] A working method of the integrated high temperature resistant and lead resistant bismuth pressure sensor according to Embodiment 5 includes the following process:

[0092] The sensor is fixed, and there are water pressure, oil pressure, air pressure, and media such as lead and bismuth around it. The sensor is first pressurized by the bottom of the threaded column 8 with holes. The medium is concentrated into the channel through the concave arc groove 23 at the bottom of the threaded column 8 with holes. The pressure is buffered to a certain extent through the narrow channel structure. Finally, the pressure is concentrated on the hemisphere A 21 and the hemisphere B. In the spherical space composed of 22, the pressure generated by this type of medium causes the pressure structure of the sensor to deform. Since the arc surface structure of the spherical space makes the pressure uniformly distributed, the diaphragm of the sensor is deformed at this time, and the metal gasket 9 is squeezed by the strain force after squeezing the piezoelectric ceramic 10. When the piezoelectric ceramic 10 is subjected to an external force in a fixed direction, electric polarization occurs inside, and charges with opposite signs are generated on the two surfaces at the same time. After the charge is generated, the graphene column 6 transmits the signal and inputs it into the filter amplifier circuit 12 of the cable output device through the metal cable 1. Then, the filter amplifier circuit 12 converts the charge signal into a voltage signal, and after filtering, it is transmitted through the built-in nozzle 14, and the final signal is recorded by the collector. When the sensor is installed, the present invention can be installed and fixed by the M10 threaded structure on the outer side of the upper shell of the sensor, or by the M5 threaded structure or thread on the outer side of the threaded column with holes at the bottom of the sensor. The applicable scenarios can respectively involve the installation and use scenarios of M5 and M10.

[0093] The pressure P is obtained by the following formula:

[0094]

[0095] Wherein, Q represents the charge, k is the piezoelectric constant of the piezoelectric ceramic, and S is the contact area between the piezoelectric ceramic and the graphene column.

[0096] When the sensor of the present invention is in use, the sensor body is placed in a pressure test environment (such as water pressure, oil pressure, air pressure, and media such as lead and bismuth), and the sensor body is connected to a cable output device through a metal cable. The cable output device is always located outside the pressure test environment and connected to a collection instrument, and the signal is recorded by the collection instrument.

[0097] In order to verify the effect of the sensor of the present invention, the harmonic response analysis of the pressure sensor designed by the present invention is carried out based on the ANSYS Workbench 18.0 collaborative simulation platform to accurately obtain the natural frequency of the pressure sensor when measuring acceleration, thereby obtaining comprehensive frequency band information to obtain the dynamic performance of the sensor. Fig.14 The frequency response curve of the present invention is shown as follows, wherein the horizontal axis is the frequency, the unit is Hz, and the vertical axis is the acceleration, the unit is m / s 2 ;from Fig.14 It shows that the frequency response of the sensor is about 68kHz, which determines the stable test range of the sensor and makes its performance meet the index requirements.

[0098] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An integrated high temperature resistant and lead resistant bismuth pressure sensor, characterized in that: The sensor body comprises a sensor main body and a cable output device, and the sensor main body and the cable output device are connected by a metal cable; the sensor main body comprises a cable shell, an outer shell, an insulating tube, a graphene column, a piezoelectric ceramic, a metal gasket, a diaphragm and a threaded column with a hole; The upper end of the cable shell is connected to the metal cable, and the lower end of the cable shell is welded to the outer shell, the diaphragm and the threaded column with holes in sequence to form an integrated shell structure. The graphene column is arranged inside the integrated shell structure, and the upper end is connected to the core wire of the metal cable; the insulating tube is located inside the integrated shell structure and wrapped around the outside of the graphene column, the lower end of the graphene column is connected to the piezoelectric ceramic and the metal gasket, the piezoelectric ceramic is completely located inside the insulating tube, the metal gasket is partially located inside the insulating tube, and the bottom of the metal gasket is embedded above the diaphragm; Insulating rings are provided at the contact points between the graphene column and the cable shell, and at the contact points between the graphene column and the outer shell.

2. The integrated high temperature resistant and lead resistant bismuth pressure sensor according to claim 1 is characterized in that: The upper end of the cable shell is a cylindrical conical structure with a through hole in the middle, through which the metal cable is inserted, and the contact between the upper end of the cable shell and the metal cable is connected and fixed by welding and sintering; The cable shell, outer shell, diaphragm and threaded column with holes are all made of 316L stainless steel.

3. The integrated high temperature resistant and lead resistant bismuth pressure sensor according to claim 2 is characterized in that: The inner surface of the shell is polished, the lower part of the outer side of the shell is an M10 thread structure, and the upper part is a hexagonal nut structure.

4. The integrated high temperature and lead resistant bismuth pressure sensor according to claim 3 is characterized in that: The lower end of the graphene column is a cylindrical entity, the upper end is provided with a boss, the center of the boss is provided with a concave circular hole, and the aperture of the concave circular hole is the same as the outer diameter of the core wire of the metal cable.

5. The integrated high temperature and lead resistant bismuth pressure sensor according to claim 4 is characterized in that: The upper and lower ends of the diaphragm are both concave structures, and a fixing groove A is provided at the edge of the upper end for fixed connection with the outer shell, and a stepped groove is provided in the middle of the upper end for installing a metal gasket and an insulating tube; a fixing groove B is provided at the lower end of the diaphragm, and the fixing groove B is used for installing a threaded column with a hole, and an inwardly concave hemisphere A is provided in the middle of the fixing groove B.

6. The integrated high temperature and lead resistant bismuth pressure sensor according to claim 5 is characterized in that: The threaded column with a hole is a cylindrical structure, and a concave hemisphere B is arranged at its upper end. After installation, hemisphere A and hemisphere B constitute the entire spherical space. The outer side of the threaded column with a hole is an M5 thread structure, and a concave arc groove is arranged at the lower end of the threaded column with a hole. A channel is arranged between the concave arc groove and the concave hemisphere B.

7. The integrated high temperature and lead resistant bismuth pressure sensor according to claim 6 is characterized in that: The cable output device comprises a rear housing, a front housing, a filter amplifier circuit, a built-in connector and a tin foil sleeve; One end of the rear shell is a conical cylindrical structure, and the other end is a cylindrical structure. The front shell is a cylindrical structure. The rear shell and the front shell are welded to form a shell structure. The metal cable penetrates into the rear shell from one end of the conical cylindrical structure and is connected and fixed by welding and sintering. A tin foil sleeve is fixedly arranged inside the rear shell, and a rectangular filter amplifier circuit is placed in the tin foil sleeve. The core wire of the metal cable is connected to the input end of the filter amplifier circuit, and the output end of the filter amplifier circuit is connected to the built-in nozzle.

8. The integrated high temperature and lead resistant bismuth pressure sensor according to claim 7 is characterized in that: The built-in nozzle comprises an integrally formed cylinder A and cylinder B, the diameter of cylinder B is larger than that of cylinder A, cylinder B is fixedly connected to the front housing, two transmission holes are arranged in the middle of the built-in nozzle, the inner wall of the transmission holes is coated with a metal conductive layer, two copper protrusions are arranged above cylinder B of the built-in nozzle, and the two copper protrusions are respectively connected to the two transmission holes; the output end of the filter amplifier circuit is connected to the two copper protrusions; The built-in nozzle is made of polytetrafluoroethylene.

9. The integrated high temperature and lead resistant bismuth pressure sensor according to claim 8, characterized in that: The assembly process is as follows: (1) placing an insulating ring into the upper inner end of the housing and fitting it tightly; placing a graphene column into the housing until the graphene column fits the insulating ring; (2) putting an insulating tube on the outside of the graphene column and fitting it with the graphene column; putting the piezoelectric ceramic into the insulating tube and fitting it with the graphene column, and putting the metal gasket into the insulating tube and fitting it with the bottom of the piezoelectric ceramic; (3) Fit the diaphragm to the lower end of the housing, and fit the inner side of the diaphragm to the insulating tube and the metal gasket, and press and weld them together; (4) Fit the threaded column with holes into the lower end of the diaphragm, press and weld them to fix; (5) Pass one end of the metal cable through the cable shell, insert the core wire of the metal cable into the concave circular hole of the graphene column and fix it, and weld and sinter the junction between the upper end of the cable shell and the metal cable; (6) Lead out the core wire of the other end of the metal cable, insert the metal cable from the conical cylindrical structure end of the rear shell into the rear shell, weld and sinter to fix it, place the tin foil sleeve inside the rear shell, place the filter amplifier circuit inside the tin foil sleeve, and connect the input end of the filter amplifier circuit to the core wire of the metal cable; fill the rear shell containing the filter amplifier circuit with glue to fix the filter amplifier circuit, fix the output end of the filter amplifier circuit to the two copper protrusions of the built-in connector with solder, apply high-temperature curing glue on the surface, insert the built-in connector into the front shell and fix it, finally dock the rear shell with the front shell and fix them by welding at the gap, and the signal is finally output from the two transmission holes of the built-in connector.

10. A working method of the integrated high temperature resistant and lead resistant bismuth pressure sensor according to claim 8, characterized in that: The process includes the following: The sensor is fixed, and there are water pressure, oil pressure, air pressure and lead-bismuth medium around it. The sensor is first compressed by the bottom of the threaded column with holes. The medium is concentrated into the channel through the concave arc groove at the bottom of the threaded column with holes. Finally, the pressure is gathered in the spherical space composed of hemisphere A and hemisphere B. The pressure generated by this type of medium causes the pressure structure of the sensor to deform. Since the arc surface structure of the spherical space makes the pressure uniform, the diaphragm of the sensor is deformed at this time. The metal gasket squeezes the piezoelectric ceramic after being subjected to strain. When the piezoelectric ceramic is subjected to external force, electric polarization occurs inside, and charges with opposite signs are generated on the two surfaces at the same time. After the charge is generated, the graphene column transmits the signal and inputs it into the filter amplifier circuit of the cable output device through the metal cable. Then, the filter amplifier circuit converts the charge signal into a voltage signal, and transmits it through the built-in nozzle after filtering. Finally, the signal is recorded by the collector; The pressure P is obtained by the following formula: Wherein, Q represents the charge, k is the piezoelectric constant of the piezoelectric ceramic, and S is the contact area between the piezoelectric ceramic and the graphene column.

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