An integrated high-temperature and lead-bismuth-resistant pressure sensor and its working method

Abstract

The present invention relates to an integrated high-temperature and lead-bismuth-resistant pressure sensor and its working method, belonging to the field of sensors. It includes 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 upper end of the cable shell is connected to the metal cable, and the lower end of the cable shell is sequentially welded to the outer shell, the diaphragm and the threaded post with holes to form an integrated shell structure. The graphene column is arranged inside the integrated shell structure and its upper end is connected to the core wire of the metal cable; the insulating tube is located inside the integrated shell structure and wraps 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, and 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 between the graphene column and the cable shell and at the contact between the graphene column and the outer shell. The present invention is not prone to short circuit or open circuit, has good sealing performance and performance, and can continuously work normally in a high-temperature lead-bismuth environment.

Description

Technical Field

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

[0002] The piezoelectric pressure sensor is a commonly used type in pressure sensors. It uses piezoelectric materials as sensitive elements. Under the action of an external force, equal amounts of charges with opposite polarities are generated on the two surfaces of the piezoelectric material, and the amount of charge is proportional to the magnitude of the applied external force. The piezoelectric pressure sensor has the characteristics of high sensitivity, good linearity, and high frequency response, and is mainly used for the measurement of dynamic pressure, such as pressure measurement in turbulence, explosion, ballistics, engine combustion, and pulsed wind tunnels. Traditional piezoelectric pressure sensors often use high-temperature wires to connect to the piezoelectric material, but this method is prone to the detachment of the solder joints in environments such as explosion and vibration, which may lead to short circuits or open circuits of the sensor; the sealing performance of traditional piezoelectric pressure sensors is poor. In some harsh high-temperature measurement environments, such as combustion fields, there are products such as dust and water vapor in the measurement environment, which 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 the traditional piezoelectric pressure sensor are single and cannot meet the installation and use in multiple scenarios, and the installation methods of the sensor need to be further increased; the traditional piezoelectric pressure sensor cannot continuously work normally in a high-temperature lead-bismuth environment, which may lead to obvious changes in parameters such as the sensitivity and linearity of the sensor. Therefore, the lead-bismuth resistance performance of the piezoelectric pressure sensor also needs to be further improved. Summary of the Invention

[0003] Aiming at the deficiencies in the prior art that the sensor is prone to short circuits or open circuits, poor sealing performance, poor performance, single installation conditions, and inability to continuously work normally in a high-temperature lead-bismuth environment, the present invention provides an integrated high-temperature and lead-bismuth-resistant pressure sensor and its working method.

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

[0005] On the one hand, the present invention provides an integrated high-temperature and lead-bismuth-resistant pressure sensor, including a sensor main body and a cable output device, which are connected by a metal cable; the sensor main body includes a cable shell, an outer shell, an insulating tube, a graphene column, a piezoelectric ceramic, a metal gasket, a diaphragm, and a threaded post with holes;

[0006] The metal cable has a solid cylindrical structure and contains 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 sequentially welded to the outer shell, the diaphragm, and the threaded stud with holes to form an integrated shell structure. The graphene column is disposed inside the integrated shell structure and is connected to the core wire of the metal cable at the upper end. The insulating tube is located inside the integrated shell structure and wraps 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, and the metal gasket is partially located inside the insulating tube. The bottom of the metal gasket is embedded above the diaphragm.

[0007] Insulating rings are provided at the contact between the graphene column and the cable shell, and at the contact between the graphene column and the outer shell. The insulating ring has a circular ring structure. The insulating ring 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 has a cylindrical conical structure with a φ3.2 through hole in the middle. The metal cable passes through the inside of the through hole, and the connection between the upper end of the cable shell and the metal cable is fixed by welding and sintering. After welding, further sintering is carried out to prevent the metal cable from shaking and improve the strength.

[0009] The cable shell, the outer shell, the diaphragm, and the threaded stud 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 316L stainless steel is used on the outside, and a laser welding sealing form is used.

[0011] Preferably, the inner surface of the outer shell is polished to present a smooth surface, which helps to reduce convective heat transfer and radiative heat transfer. The lower part of the outside of the outer shell 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.

[0012] Preferably, the lower end of the graphene column is a cylindrical solid, and the upper end is provided with a convex platform. A concave circular hole is provided in the center of the convex platform. The diameter 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 can be directly embedded into the concave circular hole of the graphene column for fixation, so as to transmit 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 the 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 collision.

[0013] In the present invention, the insulating tube has a cylindrical structure, and the graphene column can be inserted into it, and the piezoelectric ceramic and the metal gasket can be placed inside. On the one hand, it can ensure the concentricity of the graphene column, the piezoelectric ceramic, and the metal gasket, and on the other hand, it can ensure the insulation performance, and has strong insulation and support functions.

[0014] The piezoelectric ceramic has a solid cylindrical structure and can possess excellent pressure resistance and monitoring performance.

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

[0016] Preferably, both the upper end and the lower end of the diaphragm are concave structures, which helps with pressure distribution. A fixing groove A is provided at the upper end edge for fixed connection with the outer shell, and a stepped groove is provided in the middle of the upper end for the installation of the metal gasket and the insulating tube; a fixing groove B is provided at the lower end of the diaphragm, and the fixing groove B is used for the installation of the threaded stud with holes. A concave hemisphere A is provided in the middle of the fixing groove B.

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

[0018] The principle of the spherical space 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 a 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 more uniform when the sphere structure bears the same pressure, so it is beneficial to pressure distribution. The outer side of the lower end of the threaded stud with holes is an M5 thread structure, which is convenient for installation. The inner side of the lower end is an inward concave arc structure, similar to a gentle slope type funnel structure, which is convenient for concentrating the pressure into a relatively narrow through-hole structure in the center, and then the measured pressure is buffered into the overall spherical structure for distribution.

[0019] Preferably, the cable output device includes a rear housing, a front housing, a filter amplification circuit, an internal nozzle, and a tin foil sleeve;

[0020] One end of the rear housing is a conical cylinder structure, and the other end is a cylindrical structure. The front housing is a cylindrical structure. The rear housing and the front housing are welded to form a housing structure. The metal cable passes through the conical cylinder structure end and enters the interior of the rear housing, and is connected and fixed by welding and sintering; a tin foil sleeve is fixedly arranged inside the rear housing, and a rectangular filter amplification circuit is placed inside the tin foil sleeve. The amplification factor of the filter amplification circuit is 1 times, and it 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 amplification circuit, and the output end of the filter amplification circuit is connected to the internal nozzle.

[0021] Preferably, the built-in mouthpiece includes integrally formed cylinder A and cylinder B. The diameter of cylinder B is greater than that of cylinder A. Cylinder B is fixedly connected inside the front housing. Two transmission holes are provided in the middle of the built-in mouthpiece, and the inner wall of the transmission holes is coated with a metal conductive layer. Two copper protrusions are provided above cylinder B of the built-in mouthpiece, and the two copper protrusions communicate with the two transmission holes respectively. The output end of the filter amplification circuit is connected to the two copper protrusions for external connection and signal output.

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

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

[0024] (1) Place an insulating ring at the upper end inside the housing and fit it tightly; place the graphene column inside the housing until the graphene column fits with the insulating ring.

[0025] (2) Slip an insulating tube over the graphene column and fit it with the graphene column; place the piezoelectric ceramic inside the insulating tube and fit it with the graphene column, and place a metal gasket inside the insulating tube and fit it with the bottom of the piezoelectric ceramic.

[0026] (3) Fit the diaphragm with the lower end of the housing, and the inner side of the diaphragm fits with the insulating tube and the metal gasket, and at the same time press and weld it for fixation.

[0027] (4) Fit the threaded column with holes with the lower end of the diaphragm, and press and weld it for fixation.

[0028] (5) Pass one end of the metal cable through the inside of the cable housing, insert the core wire of the metal cable into the concave round hole of the graphene column for fixation, and perform welding and sintering fixation at the junction of the upper end of the cable housing and the metal cable.

[0029] (6) Lead out the core wire at the other end of the metal cable, pass the metal cable through the conical tubular structure end of the rear housing and then into the rear housing for welding and sintering fixation. Place the tin foil sleeve inside the rear housing for fixation. Place the filter amplification circuit inside the tin foil sleeve, and connect the input end of the filter amplification circuit to the core wire of the metal cable. Fill 704 silicone rubber in the rear housing containing the filter amplification circuit to fix the filter amplification circuit. Solder the output end of the filter amplification circuit to the two copper protrusions of the built-in mouthpiece, and apply high-temperature curing glue on the surface. Pass the built-in mouthpiece through the front housing and fix it. Finally, dock the rear housing with the front housing and weld at the gap for fixation to improve mechanical strength and increase service life. The signal is finally output from the two transmission holes of the built-in mouthpiece.

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

[0031] On the other hand, the present invention provides a working method of an integrated high-temperature and lead-bismuth-resistant pressure sensor based on the above, including the following processes:

[0032] Fix the sensor, and there are media such as water pressure, oil pressure, air pressure, and lead-bismuth around it. The sensor is first pressed at the bottom of the threaded column with holes. The media concentrate the media into the channel through the concave arc groove at the bottom of the threaded column with holes. Through the narrow channel structure, the pressure is buffered to a certain extent. Finally, the pressure converges in the spherical space composed of hemisphere A and hemisphere B. The pressure generated by this type of media deforms the pressure-bearing structure of the sensor. Due to the arc surface structure of the spherical space, the pressure is evenly distributed. At this time, the diaphragm of the sensor deforms, and the metal gasket squeezes the piezoelectric ceramic after being subjected to the strain force. When the piezoelectric ceramic is subjected to an external force in a certain fixed direction, an electrode polarization phenomenon occurs inside, and at the same time, charges with opposite signs are generated on the two surfaces. After the charges are generated, they are transmitted by the graphene column and input into the filter amplification circuit of the cable output device through the metal cable. Then, the charge signal is converted into a voltage signal by the filter amplification circuit, and after filtering, it is transmitted out through the built-in nozzle. Finally, the signal is recorded by the data collector; When installing the sensor of the present invention, it can be installed and fixed by the M10 threaded structure on the outer side of the upper end housing of the sensor, or fixed 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.

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

[0034]

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

[0036] For the details not elaborated in the present invention, the prior art can be adopted.

[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 selects a graphene column structure with high hardness, high strength, good electrical conductivity, and high temperature tolerance. There is a concave round hole at the upper end of the graphene column structure, which can fix and directly conduct the core wire of the cable, and can be directly installed during the assembly process, avoiding the risk of short circuit or open circuit caused by bumping in the conventional structure; the upper end of the graphene column structure is a solid cylindrical structure, which can be used to provide support, and can directly achieve concentric installation in cooperation with the insulating ring, avoiding uneven stress; the lower end of the graphene column structure is also a solid cylindrical structure, with a flat bottom, which is directly connected to the piezoelectric ceramic of the same size, with uniform stress, improving the stability of the sensor at high temperatures. In addition, graphene has good thermal stability and can withstand a relatively stable temperature of about 600 °C, and the ultimate high temperature can reach more than 4000 °C. Using a graphene column with good electrical conductivity as the connection column with the piezoelectric ceramic 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 upper concave structure is used to fix the internal parts. The lower end is provided with a concave hemisphere A, which can form a spherical space after being welded with the threaded stud with holes, which helps the pressure distribution, enables the sensor to obtain better anti-impact performance, helps 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 amplification circuit, and the filter amplification circuit is placed inside the tin foil sleeve, which can shield interference signals and increase the output accuracy and output stability.

[0041] 4. The sensor of the present invention uses 316L stainless steel material with high temperature resistance and corrosion resistance as the shell, which has the performance of high temperature resistance and resistance to lead-bismuth. 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 radiative heat transfer. On this basis, the inside of the sensor is vacuum welded during the welding process to ensure airtight welding and form a vacuum cavity inside the shell layer, thereby avoiding penetrating defects. The existence of the vacuum cavity can effectively insulate heat, 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, which can be installed and fixed by the M10 thread structure on the outer side of the upper end shell of the sensor, or fixed by the M5 thread structure or thread on the outer side of the threaded stud with holes at the bottom end of the sensor. The applicable scenarios can respectively involve the installation and use scenarios of M5 and M10, increasing the installation applicability of the sensor. Description of the Drawings

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

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

[0045] Figure 3 Assembly explosion diagram of the integrated high-temperature and lead-bismuth-resistant pressure sensor of the present invention;

[0046] Figure 4 Schematic cross-sectional structure diagram of the cable output device of the present invention;

[0047] Figure 5 Schematic three-dimensional structure diagram of the cable output device of the present invention;

[0048] Figure 6 Assembly explosion diagram of the cable output device of the present invention;

[0049] Figure 7 Schematic structure diagram of the cable housing of the present invention;

[0050] Figure 8 Schematic structure diagram of the outer housing of the present invention;

[0051] Figure 9 Three-dimensional diagram of the diaphragm structure of the present invention;

[0052] Figure 10 Schematic cross-sectional structure diagram of the diaphragm of the present invention;

[0053] Figure 11 Schematic structure diagram of the graphene column of the present invention;

[0054] Figure 12 Schematic structure diagram of the threaded column with holes of the present invention;

[0055] Figure 13 Schematic cross-sectional structure diagram of the threaded column with holes of the present invention;

[0056] Figure 14 Schematic diagram of the frequency response curve of the present invention;

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

[0058] To make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will be described in detail with reference to the accompanying drawings and specific embodiments, but not limited thereto. For those not elaborated in the present invention, they are all conventional technologies in the art.

[0059] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "left" and "right" is based on the orientation or positional relationship shown in the accompanying drawings. It is 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 orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0060] Embodiment 1

[0061] An integrated high-temperature and lead-bismuth-resistant pressure sensor, as Figures 1 to 13 shown, includes a sensor main body and a cable output device. The sensor main body and the cable output device are connected by a metal cable 1; the sensor main 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 post 8 with holes;

[0062] The metal cable 1 is of a solid cylindrical structure and contains a single core wire. The upper end of the cable shell 2 is connected to the metal cable 1. The lower end of the cable shell 2 is sequentially welded to the housing 4, the diaphragm 7 and the threaded post 8 with holes to form an integrated housing structure. The graphene column 6 is arranged inside the integrated housing structure and its upper end is connected to the core wire of the metal cable 1; the insulating tube 5 is located inside the integrated housing structure and wraps around the outside of the graphene column 6. 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, and the metal gasket 9 is partially located inside the insulating tube 5. The bottom of the metal gasket 9 is embedded above the diaphragm 7;

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

[0064] Embodiment 2

[0065] An integrated high-temperature and lead-bismuth-resistant pressure sensor, as described in Embodiment 1, the difference is that the upper end of the cable shell 2 is of a cylindrical cone structure with a φ3.2 through hole left in the middle. The metal cable 1 is inserted through the inside of this through hole, and the contact position between the upper end of the cable shell 2 and the metal cable 1 is connected and fixed by welding and sintering. After welding, further sintering is carried out to prevent the metal wire from shaking and improve the strength;

[0066] The cable shell 2, the outer shell 4, the diaphragm 7 and the perforated threaded post 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. The outside is all made of 316L stainless steel and uses a laser welding sealing form.

[0068] The inner surface of the outer shell 4 is polished, presenting a smooth surface after polishing, which helps to reduce convective heat transfer and radiative heat transfer. The lower part of the outside of the outer 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 solid, and the upper end is provided with a convex platform 17. A concave round hole is provided in the center of the convex platform 17. The aperture of the concave round 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 round hole of the graphene column 6 for fixation, so as to transmit the obtained information to the external cable, such as Figure 11 shown. The graphene column 6 has high hardness and strength, good electrical conductivity and high temperature tolerance. Using graphene with good electrical conductivity as the conductor not only plays a supporting role, but also improves the stability of the sensor at high temperatures, avoiding the risk of short circuit or open circuit caused by collision.

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

[0071] The piezoelectric ceramic 10 is a solid cylindrical structure and can have excellent pressure resistance and monitoring performance.

[0072] The metal gasket 9 is a relatively thin solid cylindrical structure and can provide planar support for the piezoelectric ceramic.

[0073] Embodiment 3

[0074] An integrated high-temperature and lead-bismuth-resistant pressure sensor, as described in Embodiment 2, the difference is that both the upper end and the lower end of the diaphragm 7 are concave structures, which helps the pressure distribution. A fixing groove A 18 is provided at the upper end edge for fixed connection with the outer shell 4, and a stepped groove 19 is provided in the middle of the upper end for the 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 the installation of the perforated threaded post 8. A concave hemisphere A 21 is provided in the middle of the fixing groove B 20, such as Figure 10 shown.

[0075] The perforated threaded post 8 is of a cylindrical structure, with a concave hemispherical body B 22 provided at its upper end. After installation, the hemispherical body A 21 and the hemispherical body B 22 form the entire spherical space. The outer side of the perforated threaded post 8 is an M5 threaded structure, and an inward concave arc groove 23 is provided at the lower end of the perforated threaded post 8. A channel is provided between the inward concave arc groove 23 and the concave hemispherical body B 22, as Figure 12 and Figure 13 shown.

[0076] The principle of the spherical space 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 a 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 more uniform when the sphere structure bears the same pressure, so it is beneficial to the pressure distribution. The outer side of the lower end of the perforated threaded post is an M5 threaded structure, which is convenient for installation. The inner side of the lower end is an inward concave arc structure, similar to a gentle slope type funnel structure, which is convenient for the pressure to be concentrated into a through hole structure with a relatively narrow center, and then the measured pressure is buffered into the overall spherical structure for distribution.

[0077] Embodiment 4

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

[0079] One end of the rear housing 11 is of a conical cylinder structure, and the other end is of a cylindrical structure. The front housing 13 is of a cylindrical structure. The rear housing 11 and the front housing 13 are welded to form a housing structure. The metal cable passes through one end of the conical cylinder structure and enters the interior of the rear housing, and is connected and fixed by welding and sintering; a tin foil sleeve 15 is fixedly arranged inside the rear housing 11, and a rectangular filter amplification circuit 12 is placed inside the tin foil sleeve 15. The filter amplification circuit 12 is of the IE174130 model, and its amplification factor is 1 times, and it has a filtering function, which 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 amplification circuit 12, and the output end of the filter amplification circuit 12 is connected to the internal nozzle 14.

[0080] As Figure 6As shown in the figure, the built-in nozzle 14 includes an integrally formed cylinder A 24 and a cylinder B 25. The diameter of the cylinder B 25 is larger than that of the cylinder A 24. The cylinder B 25 is fixedly connected inside the front housing 13. There are two transmission holes 26 in the middle of the built-in nozzle 14. The inner wall of the transmission hole 26 is coated with a metal conductive layer. There are two copper protrusions 27 above the cylinder B 25 of the built-in nozzle 14. The two copper protrusions 27 communicate with the two transmission holes 26 respectively. The output end of the filter amplification circuit 12 is connected to the two copper protrusions 27 for docking externally and outputting signals.

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

[0082] Embodiment 5

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

[0084] (1) Place an insulating ring 3 at the upper end inside the housing 4 and fit it tightly; place the graphene column 6 inside the housing 4 until the graphene column 6 fits with the insulating ring 3;

[0085] (2) Slip the insulating tube 5 over the outside of the graphene column 6 and fit it with the graphene column 6; place the piezoelectric ceramic 10 inside the insulating tube 5 and fit it with the bottom of the graphene column 6, and place the metal gasket 9 inside the insulating tube and fit it with the bottom of the piezoelectric ceramic 10;

[0086] (3) Fit the diaphragm 7 with the lower end of the housing 4. The inside of the diaphragm 7 fits with the insulating tube 6 and the metal gasket 9, and at the same time, press and weld it for fixation;

[0087] (4) Fit the threaded column 8 with holes with the lower end of the diaphragm 7, and press and weld it for fixation;

[0088] (5) Pass one end of the metal cable 1 through the inside of the cable housing 2, insert the core wire of the metal cable 1 into the concave round hole of the graphene column 6 for fixation, and perform welding and sintering fixation at the junction of 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 bismuth), 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 is connected to an acquisition instrument, and the signal is recorded by the acquisition instrument.

[0097] In order to verify the effect of the sensor of the present invention, based on the ANSYS Workbench 18.0 co-simulation platform, a harmonic response analysis is performed on the pressure sensor designed by the present invention to accurately obtain the natural frequency of the pressure sensor when measuring acceleration, so as to obtain comprehensive frequency band information and obtain the dynamic performance of the sensor. As Figure 14 shown in the schematic diagram of the frequency response curve of the present invention, where the abscissa is the frequency, the unit is Hz, and the ordinate is the acceleration, the unit is m / s 2 ; From Figure 14 it shows that: the frequency response of the sensor is about 68 kHz, which determines the stable test range of the sensor and makes its performance meet the index requirements.

[0098] The above is the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope 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 resistant 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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