Capacitive pressure sensor

Abstract

This application relates to the field of pressure sensor technology, specifically capacitive pressure sensors. A capacitive pressure sensor includes a housing, a fixing component, a capacitor component, a temperature control mechanism, and a clamping component. By integrating the clamping component, fixing component, and capacitor component into a core sensor unit, and with each functional component centrally located within the fixing component, the internal structure of the entire device is significantly simplified, overcoming the drawbacks of complex structures in existing products. This integrated layout eliminates a large number of independent supporting parts, reducing the processing difficulty and performance requirements of components, making component production easier. The sensor core unit adopts a modular pre-assembly method, allowing the core unit to be installed entirely into the housing during assembly, simplifying the step-by-step assembly process and making assembly convenient and efficient. Reduced component processing difficulty and streamlined assembly procedures effectively reduce production material and labor costs, compressing production costs from both the processing and assembly ends, and facilitating mass production.

Description

Technical Field

[0001] This application generally relates to the field of pressure sensor technology, and more specifically, to capacitive pressure sensors. Background Technology

[0002] Capacitive pressure sensors primarily obtain the pressure inside the measured space by measuring the capacitance value. The most common structure uses a metal conductive diaphragm as one electrode of the capacitor, forming a capacitor with a conductive coating on a ceramic substrate. When the metal diaphragm is subjected to external pressure, a pressure difference is formed on both sides, causing the metal diaphragm to deform. This changes the distance between the metal diaphragm and the conductive layer on the ceramic substrate, thereby changing the capacitance value and determining the pressure of the measured space.

[0003] Existing capacitive pressure sensors have a relatively complex structure, require high-precision manufacturing of components, and are relatively expensive. Summary of the Invention

[0004] This application provides a capacitive pressure sensor. It solves the technical problems of existing capacitive pressure sensors, which have relatively complex structures, high requirements for component processing, and relatively high costs.

[0005] This application provides a capacitive pressure sensor, including a housing, a fixing component, a capacitor component, a temperature control mechanism, and a clamping component; The fixing component is disposed inside the housing, and the fixing component has an air inlet that penetrates the housing and is sealed, and the air inlet is used to connect to the gas to be measured; The capacitor assembly is disposed on the fixed assembly and seals the air inlet. The capacitor assembly, the outer shell, and the fixed assembly together form a vacuum cavity. The capacitor assembly is used to deform under the pressure of the gas being measured to generate a capacitance signal. The temperature control mechanism is mounted on the fixed component and is used to adjust the temperature of the capacitor component; The clamping component is disposed on the fixing component and connected to the capacitor component, and is used to adjust the initial capacitance of the capacitor component. The clamping component, the fixing component, and the capacitor component constitute the core unit of the sensor.

[0006] In one embodiment, the temperature control mechanism includes a heating coil and a temperature control contact pin; The heating coil is disposed on the outer wall of the fixing component; The temperature control contact pin is disposed on the outer shell and extends into the vacuum cavity, and is electrically connected to the heating coil. It is used to transmit control signals to control the operation of the heating coil and maintain the constant temperature of the capacitor assembly.

[0007] In one embodiment, the capacitor assembly includes a diaphragm, a disk, and a gasket; The diaphragm is fixed to the fixing assembly and seals the air inlet, and is used to sense the pressure of the gas being measured and deform accordingly. The disk is located on the side of the diaphragm opposite to the air inlet, and is used to form a capacitor plate with the diaphragm. The gasket is placed between the diaphragm and the disk to precisely adjust the initial distance between the diaphragm and the disk and avoid hard contact.

[0008] In one embodiment, the capacitor assembly further includes a protective cover; The protective cover is fixed to the fixing component and located on the side of the diaphragm facing the air inlet. A gap is formed between the protective cover and the fixing component, and the gas to be measured contacts the diaphragm through the gap. The protective cover is used to buffer the impact of the gas being tested on the diaphragm.

[0009] In one embodiment, the fixing assembly includes a chassis, a ring, and a connecting pipe; The chassis is fixed inside the outer casing; The ring is mounted on the chassis and is used to fix the capacitor assembly; One end of the connector passes through and connects to the chassis, while the other end extends out of the housing to form the air inlet. The connector is used to deliver the gas to be measured to the capacitor assembly.

[0010] In one embodiment, the clamping assembly includes a screw, a disk clamping spring, a connecting ring, and a pressure ring; The screw is screwed into the fixing component; The disk clamping spring is sleeved on the screw; The connecting ring has a connecting hole, the screw passes through the connecting hole, and the two ends of the disk clamping spring abut against the end of the screw and one side of the connecting ring, respectively. The pressure ring is fixed to the other side of the connecting ring and abuts against the capacitor assembly, and is used to squeeze the capacitor assembly under the elastic force of the disk clamping spring to adjust the initial capacitance of the capacitor assembly.

[0011] In one embodiment, the capacitive pressure sensor further includes a capacitive signal output mechanism, which includes a central contact needle and a guide post. The central contact pin is disposed on the outer shell, with one end electrically connected to the external circuit and the other end extending into the vacuum cavity; The guide post is disposed in the vacuum cavity, and its two ends are electrically connected to the center contact pin and the capacitor assembly, respectively, for exporting the capacitor signal to the external circuit.

[0012] In one embodiment, the capacitive pressure sensor further includes a vacuum pumping assembly, which includes a vacuum agent tube and a vacuum pumping tube. The vacuum agent tube is fixed to the outer shell and connected to the vacuum cavity, and is used to house the getter. The vacuum tube is fixed to the outer shell and connected to the vacuum cavity, and is used to evacuate the vacuum cavity to form a closed vacuum environment.

[0013] In one embodiment, the capacitive pressure sensor further includes a stray capacitance elimination mechanism, which includes a contact sleeve and an electrode contact spring. The contact sleeve is disposed on the outer shell and extends into the vacuum cavity; One end of the electrode contact spring abuts against the contact sleeve, and the other end abuts against the capacitor assembly, which is used to press the capacitor assembly, remove stray capacitance, and reduce signal interference.

[0014] In one embodiment, the housing includes a shell and a top plate; One end of the housing is an open end, and the other end has a through hole. The air inlet passes through the through hole and is sealed. The top plate is located at the open end of the shell and closes the shell.

[0015] Compared with the prior art, this application has the following beneficial technical effects: First, this application integrates the clamping component, fixing component, and capacitor component into a core sensor unit. Each functional component is centrally located within the fixing component, significantly simplifying the overall internal structure and overcoming the drawbacks of complex existing product structures. This integrated layout eliminates a large number of independent supporting parts, reducing the processing difficulty and performance requirements of components, making component production easier.

[0016] Secondly, the sensor core unit adopts a modular pre-assembly method, allowing the core unit to be installed as a whole into the housing during assembly, simplifying the step-by-step assembly process and making assembly operations convenient and efficient. Reduced component processing difficulty and streamlined assembly procedures effectively decrease production material and labor consumption, compressing production costs from both the processing and assembly ends, thus facilitating mass production.

[0017] It should be understood that the content described in this application summary is not intended to limit the key or essential features of the embodiments of this application, nor is it intended to restrict the scope of this application. Other features of this application will become readily apparent from the following description. Attached Figure Description

[0018] The above and other features, advantages, and aspects of the embodiments of this application will become more apparent from the accompanying drawings and the following detailed description. In the drawings, the same or similar reference numerals denote the same or similar elements, wherein: Figure 1 A schematic diagram of the structure of a capacitive pressure sensor according to an embodiment of this application is shown; Figure 2 A first cross-sectional view of a capacitive pressure sensor according to an embodiment of this application is shown; Figure 3 A second cross-sectional view of a capacitive pressure sensor according to an embodiment of this application is shown; Figure 4 A schematic diagram of the structure of the sensor core component according to an embodiment of this application is shown; Figure 5 An exploded view of the sensor core component according to an embodiment of this application is shown; Figure 6 A cross-sectional view of the core sensor component according to an embodiment of this application is shown; Figure 7 A schematic diagram of the housing according to an embodiment of this application is shown; Figure 8 A schematic diagram of the top plate and its connection structure according to an embodiment of this application is shown; in, 1. Outer shell; 11. Housing; 12. Top plate; 2. Fixed components; 21. Chassis; 22. Ring body; 23. Connecting pipe; 3. Capacitor assembly; 31. Diaphragm; 32. Disk; 33. Gasket; 34. Protective cover; 4. Temperature control mechanism; 41. Heating coil; 42. Temperature control contact pin; 5. Clamping assembly; 51. Screw; 52. Disk clamping spring; 53. Connecting ring; 54. Pressure ring; 6. Capacitive signal output mechanism; 61. Center contact pin; 62. Guide post; 7. Vacuum assembly; 71. Vacuum agent tube; 72. Vacuum tube; 8. Stray capacitance elimination mechanism; 81. Contact sleeve; 82. Electrode contact spring. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] Furthermore, the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0021] In this application, the core sensor unit is formed by integrating the clamping component, the fixing component, and the capacitor component. Each functional component is centrally located within the fixing component, significantly simplifying the internal structure of the entire device and overcoming the drawbacks of the complex structure of existing products. This integrated layout eliminates a large number of independent supporting parts, reduces the processing difficulty and performance requirements of components, and makes component production easier. It solves the technical problems of existing capacitive pressure sensors, which have relatively complex structures, high processing requirements for components, and relatively high costs.

[0022] Reference Figures 1-8 As shown in the figure, this application provides a capacitive pressure sensor. The sensor body includes a housing 1, a fixing component 2, a capacitor component 3, a temperature control mechanism 4, and a pressing component 5. The pressing component 5, the fixing component 2, and the capacitor component 3 together form an integrated sensor core unit, which is centrally arranged inside the housing 1. It has a high degree of structural integration and strong overall assembly.

[0023] The fixing component 2 is fixedly installed inside the housing 1, serving as the supporting base for the entire sensor core unit. The fixing component 2 has an air inlet, which runs through the housing 1 and is connected to the housing 1 with a sealed structure, ensuring the airtightness of the air inlet position and effectively preventing external gas from seeping in or internal gas from leaking. The gas to be measured can be stably and independently introduced into the sensor through the air inlet, providing an independent air intake channel for pressure detection.

[0024] The capacitor assembly 3 is integrally assembled and fixed on the fixing assembly 2, and the capacitor assembly 3 completely covers and seals the upper opening of the air inlet, achieving complete isolation between the air inlet channel and the cavity structure. The capacitor assembly 3, the outer shell 1, and the fixing assembly 2 are mutually sealed and enclosed, jointly constructing a closed and independent vacuum cavity. This vacuum cavity can isolate external air, humidity, and environmental disturbances, providing a stable and pure vacuum reference environment for capacitive pressure detection. When the gas to be measured is introduced into the air inlet, the gas pressure can directly act on the surface of the capacitor assembly 3, causing the capacitor assembly 3 to undergo controllable elastic deformation, changing the relative spacing of the internal capacitor plates, thereby generating a capacitance signal corresponding to the gas pressure value in real time, realizing the accurate conversion between pressure signal and electrical signal.

[0025] The temperature control mechanism 4 is assembled on the fixed component 2 and can be arranged in close contact with the fixed component 2 in the surrounding area of ​​the capacitor component 3. It can adjust and control the working environment temperature of the capacitor component 3 in real time, avoid the capacitor parameters from drifting due to fluctuations in the ambient temperature, and ensure that the capacitor component 3 is always in a constant and stable working temperature range.

[0026] The clamping component 5 is assembled on the fixing component 2 and is connected and cooperated with the capacitor component 3. The pre-tightening state of the capacitor component 3 can be finely adjusted by mechanical adjustment to accurately correct the initial capacitance value of the capacitor component 3. This can effectively compensate for the initial zero-point deviation caused by the machining tolerance of the parts and the misalignment of the assembly, and ensure the stability of the zero-point accuracy of the sensor after leaving the factory and after long-term operation.

[0027] This application integrates the fixing component 2, capacitor component 3, and clamping component 5 into the sensor core unit. All functional components are centrally arranged using the fixing component 2, significantly simplifying the internal structure of the entire device and overcoming the drawbacks of complex structures in existing products. The integrated layout eliminates a large number of independent supporting parts, reducing the processing difficulty and performance requirements of components, making component production easier. The sensor core unit adopts a modular pre-assembly method, allowing the core unit to be installed entirely into the housing during assembly, simplifying the step-by-step assembly process and making assembly convenient and efficient. Reduced component processing difficulty and streamlined assembly procedures effectively reduce production material and labor costs, compressing production costs from both the processing and assembly ends, and facilitating mass production.

[0028] Furthermore, the temperature control mechanism 4 actively maintains a constant temperature, suppressing temperature drift at its source and addressing the shortcomings of traditional sensors that suffer from significant accuracy deviations due to temperature variations. Simultaneously, the vacuum chamber structure enclosed by the outer shell 1, fixing component 2, and capacitor component 3 isolates the sensor from external environmental interference. Combined with the integrated core unit structure, this enhances overall structural stability, significantly improving the sensor's measurement accuracy, repeatability, and long-term operational stability in wide-temperature-range, high-precision, low-pressure detection scenarios.

[0029] Reference Figure 2 and Figure 3 As shown, in one embodiment, the temperature control mechanism 4 includes a heating coil 41 and a temperature control contact pin 42.

[0030] The heating coil 41 is attached and fixed to the outer wall of the fixing component 2, and can generate heat by relying on electrical energy to uniformly heat the surrounding structure.

[0031] The temperature control contact pin 42 is mounted on the housing 1. One end of the pin extends into the vacuum chamber and is electrically connected to the heating coil 41, while the other end is connected to the control circuit. The temperature control contact pin 42 can transmit external control signals to start, stop, and adjust the working state of the heating coil 41, so that the core unit of the sensor is always kept within a constant temperature range.

[0032] The heating coil 41 is installed in close contact with the surface, resulting in high thermal conductivity and uniform heat distribution. Combined with the temperature control contact pin 42, it enables automated temperature control, effectively suppressing temperature drift and preventing temperature changes from interfering with capacitance parameters, thereby further improving the accuracy of pressure detection results.

[0033] Reference Figures 2-6 As shown, in one embodiment, the capacitor assembly 3 includes a diaphragm 31, a disk 32, and a pad 33.

[0034] The diaphragm 31 is fixedly installed on the fixed component 2, and at the same time seals and isolates the air inlet. It can directly sense the pressure of the gas being measured and generate elastic deformation with changes in air pressure.

[0035] The disk 32 is located on the side of the diaphragm 31 away from the air inlet. The disk 32 and the diaphragm 31 are arranged opposite each other, and together they form the two plates of the capacitor. Changes in the distance between the plates will directly change the capacitance value.

[0036] The gasket 33 is sandwiched between the diaphragm 31 and the disk 32. It precisely limits the initial distance between the diaphragm 31 and the disk 32 by its own thickness, while isolating the two plates to prevent them from making hard contact and causing structural damage.

[0037] The diaphragm 31 is highly sensitive and can accurately respond to minute changes in air pressure; the gasket 33 precisely controls the initial spacing of the plates, ensuring the stability of the initial parameters of the capacitor, while also providing protection; the plate combination structure is simple and reliable, with a fast sensing response speed, and can stably complete the conversion of pressure to capacitance signal.

[0038] Furthermore, referring to Figures 2-6 As shown, in one embodiment, the capacitor assembly 3 is further provided with a protective cover 34.

[0039] The protective cover 34 is fixedly installed on the fixing component 2 and is located on the side of the diaphragm 31 facing the air inlet. A communication gap is reserved between the protective cover 34 and the fixing component 2, through which the gas to be measured can flow smoothly to the surface of the diaphragm 31.

[0040] The protective cover 34 can block the oncoming airflow, buffer the impact of the gas being measured on the diaphragm 31, and reduce the damage and deformation of the diaphragm 31 caused by airflow disturbance.

[0041] Reference Figures 2-6 As shown, in one embodiment, the fixing component 2 includes a chassis 21, a ring 22, and a connecting pipe 23.

[0042] The chassis 21 is fixedly assembled inside the outer shell 1, serving as the load-bearing base for the entire fixed assembly 2 and providing stable installation support for various structures above.

[0043] The ring 22 is mounted on the surface of the chassis 21 and uses its own ring structure to limit and fix the capacitor assembly 3, preventing the capacitor assembly 3 from shifting position.

[0044] The connector 23 is a hollow tubular structure. One end passes through and connects to the chassis 21, while the other end extends outward from the outer shell 1 and forms an air inlet, which can smoothly deliver the external gas to be measured to the area where the capacitor assembly 3 is located.

[0045] The chassis 21 ensures the overall structure is firmly installed, the ring 22 accurately positions the capacitor assembly 3 to avoid misalignment during assembly, and the connecting pipe 23 forms an independent closed air passage, ensuring smooth gas delivery and good sealing, providing reliable air intake conditions for pressure detection.

[0046] like Figures 2-6 As shown, in one embodiment, the chassis 21 is a disc-shaped structure with a groove at its upper end and a flange at its lower end that communicates with the groove. The flange penetrates the outer shell 1 and is sealed to the outer shell 1. The outer wall of the pipe 23 is fixedly connected to the inner wall of the flange or detachably connected. The protective cover 34 is disposed in the groove, and a gap is formed between the two. The chassis 21, diaphragm 31, and ring 22 are connected sequentially from bottom to top and are coaxially arranged. The gasket 33 and disk 32 are sequentially arranged on the upper part of the diaphragm 31 and located inside the ring 22. The connecting pipe 23 is welded (laser welding, electron beam welding, etc.) to the chassis 21, diaphragm 31, ring 22, and protective cover 34 to form a whole. The heating coil 41 is arranged outside the ring 22 and is used to regulate the temperature of the capacitor assembly 3.

[0047] Reference Figures 2-6 As shown, in one embodiment, the clamping assembly 5 includes a screw 51, a disk clamping spring 52, a connecting ring 53, and a pressure ring 54.

[0048] The screw 51 is threadedly connected to the fixing component 2 and can change its axial position by rotation. The upper surface of the ring 22 is provided with a screw hole, and the screw 51 is screwed into the screw hole.

[0049] The disk clamping spring 52 is sleeved on the outside of the screw 51, and can generate compression or rebound deformation as the position of the screw 51 changes, continuously outputting stable elastic force.

[0050] A connecting hole is provided in the middle of the connecting ring 53, through which the screw 51 passes. The two ends of the disk clamping spring 52 abut against the end of the screw 51 and one side of the connecting ring 53, respectively.

[0051] The pressure ring 54 is fixed to the other side of the connecting ring 53 and abuts against the capacitor assembly 3.

[0052] The disk clamping spring 52 is always compressed, applying a downward elastic force to the connecting ring 53, which in turn causes the pressure ring 54 to apply a downward squeezing force to the capacitor assembly 3. When the screw 51 is turned clockwise, the screw 51 enters the screw hole, further compressing the disk clamping spring 52, increasing the elastic force applied by the disk clamping spring 52 to the connecting ring 53, and thus increasing the squeezing force applied by the pressure ring 54 to the capacitor assembly 3. At this time, the gasket 33 is further flattened, the distance between the plates of the diaphragm 31 and the disk 32 is shortened, the area of ​​the two plates facing each other remains unchanged, and the inter-electrode medium remains a vacuum. According to the capacitance calculation formula, the capacitance value increases accordingly, and the detection zero point shifts towards a larger capacitance value. Similarly, when the screw 51 is turned counterclockwise, the spring compression decreases, the distance between the plates increases, the initial capacitance decreases, and the detection zero point shifts towards a smaller capacitance value. Using this adjustment characteristic, the sensor zero point calibration and initial parameter calibration can be completed, eliminating assembly and processing errors, and ensuring a stable linear relationship between the capacitance change and the measured gas pressure, thus guaranteeing the accuracy of subsequent pressure measurements.

[0053] Furthermore, an annular groove is formed on the lower surface of the pressure ring 54, and the cross-section of the annular groove is set as a conical structure. The upper outer periphery of the disk 32 is machined with a conical chamfer that matches the annular groove. During assembly and clamping, the conical groove and the conical chamfer fit together, which can automatically center and position the pressure ring 54 and the disk 32, achieving centering and clamping, effectively ensuring the overall coaxiality of the capacitor assembly 3, and avoiding misalignment of the plates caused by uneven clamping force. With the adjustment action of the screw 51 and the disk clamping spring 52, the pressure ring 54 can apply pressure evenly along the axial direction, which not only ensures the consistency of the plate spacing adjustment, but also prevents uneven deformation caused by eccentric force, further improving the initial capacitor calibration accuracy and sensor operation stability.

[0054] Reference Figures 2-6 As shown, in one embodiment, the sensor further includes a capacitance signal output mechanism 6, which includes a central contact pin 61 and a guide post 62.

[0055] The center contact pin 61 is mounted on the housing 1, with one end extending to the outside of the housing 1 and electrically connected to the external circuit, and the other end extending into the vacuum chamber as a carrier for external signal transmission.

[0056] The guide post 62 is arranged inside the vacuum chamber, and its two ends are electrically connected to the center contact pin 61 and the capacitor assembly 3, respectively. It can stably transmit the capacitor signal generated by the capacitor assembly 3 to the center contact pin 61 and finally to the external circuit.

[0057] Specifically, the upper surface of the disk 32 is provided with a connection hole, and the inner wall of the connection hole is provided with a coating. The coating is a conductive plating layer for the connection hole, ensuring reliable conductivity between the guide post and the disk. One end of the guide post 62 is in direct contact with the center contact pin 61 to achieve electrical connection, and the other end is inserted into the connection hole to contact the coating, thereby achieving electrical connection with the disk 32, so as to export the capacitance signal measured by the diaphragm 31 and the disk 32.

[0058] Reference Figures 2-6 As shown, in one embodiment, the sensor further includes a vacuum assembly 7, which includes a vacuum agent tube 71 and a vacuum tube 72.

[0059] The vacuum agent tube 71 is fixed on the outer shell 1. The inside of the tube is connected to the vacuum chamber. The tube can be filled with getter to adsorb residual gas molecules inside the chamber.

[0060] The vacuum tube 72 is also fixed on the outer shell 1 and connected to the vacuum chamber. It can be connected to an external pumping device to pump air from the vacuum chamber. After pumping is completed, it can be sealed to form a closed vacuum environment in the chamber.

[0061] The vacuum tube 72 can quickly complete the vacuuming operation of the cavity and create the vacuum environment required for detection; the vacuum agent tube 71, together with the getter, continuously adsorbs residual gas, maintains the cavity vacuum level for a long time, avoids the vacuum level from decreasing and affecting the detection benchmark, and ensures the long-term stable operation of the sensor.

[0062] Reference Figures 2-6 As shown, in one embodiment, the sensor further includes a stray capacitance elimination mechanism 8, which includes a contact sleeve 81 and an electrode contact spring 82.

[0063] The contact sleeve 81 is fixedly installed on the outer shell 1, with one end extending into the vacuum cavity, serving the functions of positioning and insulation isolation.

[0064] One end of the electrode contact spring 82 abuts against the contact sleeve 81, and the other end is tightly attached to the capacitor assembly 3. It continuously presses the capacitor assembly 3 with its own elasticity, and at the same time, it can eliminate stray capacitance generated during operation and reduce the interference of stray signals on the effective detection signal.

[0065] Reference Figures 1-8 As shown, in one embodiment, the outer casing 1 includes a housing 11 and a top plate 12.

[0066] One end of the housing 11 is set as an open end, and the other end is machined with a through hole. The air inlet passes through the through hole and completes the sealing connection. Specifically, the bottom end of the chassis 21 is provided with a flange, which extends out of the through hole, and the outer wall of the flange is fixedly connected to the inner wall of the through hole to achieve a seal. The housing 11 is a rigid cavity structure that carries all internal components and forms a vacuum cavity with the chassis 21, diaphragm 31 and top plate 12.

[0067] The top plate 12 is installed at the open end of the shell 11 to completely seal the open position, so that the shell 11 forms a complete sealed cavity. The top plate 12 and the shell 11 can be detachably connected or welded into a whole. like Figure 8 As shown, the top plate 12 can be a circular plate. The temperature control contact needle 42, the center contact needle 61, and the contact sleeve 81 all penetrate the top plate 12 and are fixed to the top plate 12 by glass sealing. The vacuum agent tube 71 and the vacuum tube 72 are fixed to the top plate 12 by ultrasonic welding, argon arc welding, electron beam welding, etc.

[0068] Specifically, the contact sleeve 81 has a tubular structure, with the central contact needle 61 penetrating through the contact sleeve 81. The two are coaxially arranged and do not come into contact, and a glass seal is provided between them.

[0069] The capacitive pressure sensor provided in this application operates as follows: First, assemble the fixing component 2, capacitor component 3, and clamping component 5. Using a tool, rotate screw 51, and with the help of disk clamping spring 52, drive pressure ring 54 to compress capacitor component 3. The conical fit between pressure ring 54 and disk 32 achieves centering and clamping, completing initial capacitor calibration and zero-point setting, eliminating processing and assembly errors. After successful debugging, mount and seal the outer casing 1 onto the outside of all external components. Then, activate the external temperature control circuit, controlling the heating coil 41 via temperature control contact pin 42 to maintain a constant temperature for fixing component 2 and capacitor component 3, suppressing temperature drift. Finally, evacuate and seal the cavity via vacuum tube 72, maintaining the internal vacuum environment with vacuum agent tube 71. Connect the air inlet to the gas pipeline being tested, and pressure testing can then commence.

[0070] During testing, the gas to be tested enters the interior through the inlet, passes through the gap between the protective cover 34 and the fixed component 2, and smoothly contacts the diaphragm 31. The protective cover 34 effectively buffers the airflow impact, preventing damage to the diaphragm 31. The diaphragm 31 deforms under the pressure of the gas, changing its relative distance to the disk 32 and generating a capacitance signal. During operation, the electrode contact spring 82 continuously contacts the capacitor component 3, removing stray capacitance and reducing signal interference. The capacitance signal is transmitted to the central contact needle 61 through the guide post 62, and finally stably delivered to the external circuit, realizing real-time, high-precision detection of gas pressure. The entire process is simple to operate and can operate stably for a long time in a wide temperature range environment.

[0071] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

[0072] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method of preparation, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method of preparation, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method of preparation, article, or apparatus that includes the element.

[0073] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A capacitive pressure sensor, characterized in that, include: Outer shell (1); A fixing component (2) is disposed inside the housing (1). The fixing component (2) has an air inlet that penetrates the housing (1) and is sealed. The air inlet is used to connect to the gas to be tested. A capacitor assembly (3) is disposed on the fixed assembly (2) and seals the air inlet. The capacitor assembly (3), the outer shell (1) and the fixed assembly (2) together form a vacuum cavity. The capacitor assembly (3) is used to deform under the action of the gas pressure to be measured and generate a capacitance signal. Temperature control mechanism (4) is disposed on the fixed component (2) and is used to adjust the temperature of the capacitor component (3); The clamping component (5) is disposed on the fixing component (2) and connected to the capacitor component (3) for adjusting the initial capacitance of the capacitor component (3). The clamping component (5), the fixing component (2) and the capacitor component (3) constitute the core unit of the sensor.

2. The capacitive pressure sensor according to claim 1, characterized in that, The temperature control mechanism (4) includes: A heating coil (41) is disposed on the outer wall of the fixing component (2); Temperature control contact pin (42) is disposed on the outer shell (1) and extends into the vacuum cavity. It is electrically connected to the heating coil (41) and is used to transmit control signals to control the operation of the heating coil (41) and maintain the constant temperature of the capacitor assembly (3).

3. The capacitive pressure sensor according to claim 1, characterized in that, The capacitor assembly (3) includes: A diaphragm (31) is fixed on the fixing assembly (2) and seals the air inlet, used to sense the pressure of the gas being measured and deform accordingly; The disk (32) is located on the side of the diaphragm (31) opposite to the air inlet, and is used to form a capacitor plate with the diaphragm (31); A gasket (33) is provided between the diaphragm (31) and the disk (32) to precisely adjust the initial distance between the diaphragm (31) and the disk (32) and avoid hard contact.

4. The capacitive pressure sensor according to claim 3, characterized in that, The capacitor assembly (3) also includes a protective cover (34); The protective cover (34) is fixed on the fixing component (2) and located on the side of the diaphragm (31) facing the air inlet. A gap is formed between the protective cover (34) and the fixing component (2), and the gas to be measured contacts the diaphragm (31) through the gap. The protective cover (34) is used to buffer the impact of the gas being tested on the diaphragm (31).

5. The capacitive pressure sensor according to claim 1, characterized in that, The fixing component (2) includes: The chassis (21) is fixed inside the outer shell (1); The ring (22) is disposed on the chassis (21) and is used to fix the capacitor assembly (3). The connector (23) has one end that passes through and connects to the chassis (21), and the other end that extends out of the outer shell (1) to form the air inlet. The connector (23) is used to deliver the gas to be measured to the capacitor assembly (3).

6. The capacitive pressure sensor according to claim 1, characterized in that, The clamping assembly (5) includes: Screw (51) is screwed into the fixing component (2); The disk clamping spring (52) is sleeved on the screw (51); A connecting ring (53) has a connecting hole, through which the screw (51) passes. The two ends of the disk clamping spring (52) abut against the end of the screw (51) and one side of the connecting ring (53), respectively. A pressure ring (54) is fixed on the other side of the connecting ring (53) and abuts against the capacitor assembly (3). It is used to squeeze the capacitor assembly (3) under the elastic force of the disk clamping spring (52) and adjust the initial capacitance of the capacitor assembly (3).

7. The capacitive pressure sensor according to claim 1, characterized in that, It also includes a capacitor signal output mechanism (6), which includes: A central contact pin (61) is disposed on the outer shell (1), with one end electrically connected to an external circuit and the other end extending into the vacuum chamber; The guide post (62) is located inside the vacuum cavity and its two ends are electrically connected to the center contact pin (61) and the capacitor assembly (3) respectively, for exporting the capacitor signal to the external circuit.

8. The capacitive pressure sensor according to claim 1, characterized in that, It also includes a vacuum pumping assembly (7), which comprises: A vacuum agent tube (71) is fixed on the outer shell (1) and connected to the vacuum cavity for storing a getter; A vacuum tube (72) is fixed on the outer shell (1) and connected to the vacuum cavity, and is used to evacuate the vacuum cavity to form a closed vacuum environment.

9. The capacitive pressure sensor according to claim 1, characterized in that, It also includes a stray capacitance elimination mechanism (8), which includes: A contact sleeve (81) is disposed on the outer shell (1) and extends into the vacuum chamber; The electrode contact spring (82) abuts against the contact sleeve (81) at one end and against the capacitor assembly (3) at the other end, and is used to press the capacitor assembly (3) to remove stray capacitance and reduce signal interference.

10. The capacitive pressure sensor according to claim 1, characterized in that, The outer casing (1) includes: The housing (11) has an open end at one end and a through hole at the other end, with the air inlet passing through the through hole and being sealed. A top plate (12) is provided at the open end of the housing (11) for closing the housing (11).

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