Wide-range vacuum gauge composite gauge tube with self-calibration function

Abstract

The invention relates to the technical field of vacuum gauge test and calibration, in particular to a wide-range vacuum gauge composite gauge tube with a self-calibration function, which comprises a magnetic suspension rotor vacuum sensing assembly, a vacuum chamber, an ionization type vacuum sensing assembly and an MEMS (Micro Electro Mechanical System) capacitance film vacuum sensing assembly, wherein the magnetic suspension rotor vacuum sensing assembly is connected with the outer pipe wall of the vacuum chamber through a CF16 flange; the ionization type vacuum sensing assembly is fixedly welded on a CF35 flange electrode below the vacuum chamber; and the MEMS capacitance film vacuum sensing assembly is arranged below the ionization type vacuum sensing assembly and is isolated through the shielding plate. According to the invention, the embedding of the high-vacuum-range vacuum reference standard appliance is realized, the in-situ / online calibration of the MEMS capacitor film vacuum sensing assembly corresponding to the medium-low vacuum range and the high-vacuum / ultrahigh-vacuum-range ionization type vacuum sensing assembly is realized by utilizing the good linearity and long-term stability of the high-vacuum-range vacuum reference standard appliance, the disassembly in the cycle detection process is avoided, and the detection efficiency is improved. And a self-calibration function is realized.

Description

Technical Field

[0001] This application relates to the field of vacuum gauge testing and calibration technology, and more specifically, to a wide-range vacuum gauge calibration tube with self-calibration function. Background Technology

[0002] Due to limitations in measurement principles, vacuum gauges based on a single principle cannot achieve full coverage of the range from atmospheric pressure to ultra-high vacuum (up to 15 orders of magnitude). Currently, the widely adopted approach is to combine vacuum sensing components based on two or three principles to form a wide-range composite vacuum gauge.

[0003] Existing wide-range vacuum gauges often employ various configurations, such as Pirani vacuum sensing components combined with thermionic vacuum sensing components, capacitive thin-film vacuum sensing components combined with thermionic vacuum sensing components, and resistive vacuum sensing components combined with cold cathode reverse magnetron vacuum sensing components. These composite vacuum gauges frequently suffer from issues like poor linearity, inaccurate switching regions or significant time delays, and substantial temperature effects. Furthermore, to ensure measurement accuracy and metrological traceability, these composite vacuum gauges require periodic removal from the vacuum system and delivery to metrology departments for verification and calibration. This process not only causes equipment downtime, disrupting production and experimental continuity, but also incurs high operating and maintenance costs. Summary of the Invention

[0004] This application provides a wide-range vacuum gauge composite tube with self-calibration function, which solves the problems of poor measurement accuracy, frequent periodic disassembly and verification, and poor reliability of overlapping areas in existing wide-range composite vacuum gauges.

[0005] To achieve the above objectives, this application provides a wide-range vacuum gauge calibration tube with self-calibration function, including a magnetic levitation rotor vacuum sensing component, a vacuum chamber, an ionization-type vacuum sensing component, and a MEMS capacitor film vacuum sensing component. The magnetic levitation rotor vacuum sensing component is disposed outside the vacuum chamber and connected to the outer wall of the vacuum chamber via a CF16 flange. The ionization-type vacuum sensing component is disposed inside the vacuum chamber and fixedly welded to a CF35 flange electrode below the vacuum chamber. The MEMS capacitor film vacuum sensing component is disposed below the ionization-type vacuum sensing component and is isolated by a shielding plate.

[0006] Furthermore, the magnetic levitation rotor vacuum sensing assembly includes a support rod, a measuring head, a rotor, and a vacuum tube, wherein: the support rod is fixed on the housing of the assembly; the measuring head is disposed between the support rods; the rotor is suspended in the magnetic field generated by the measuring head and is located inside the vacuum tube; the vacuum tube is connected to the vacuum chamber through a CF16 flange to form an integral vacuum passage.

[0007] Furthermore, the rotor is a spherical rotor with a surface roughness ≤0.01μm and a ball diameter variation ≤0.08μm.

[0008] Furthermore, the vacuum tube is made of non-magnetic stainless steel with high electrical conductivity.

[0009] Furthermore, the ionization-type vacuum sensing component includes a cathode, a grid, and a collector, wherein: the grid is a squirrel cage structure closed at both ends, and the material is a platinum-iridium alloy; the collector is located at the axial position of the grid structure and is used to collect positive ions passing through the grid, and the material is a molybdenum wire; the cathode is located on the outside of the grid, and the material is a yttrium-iridium oxide wire with a coating thickness ≤40μm.

[0010] Furthermore, the reference cavity vacuum pressure of the MEMS capacitive thin-film vacuum sensing component is ≤10. -3 Pa level, inter-electrode capacitance temperature drift ≤0.01%FS.

[0011] Furthermore, the shielding plate is fixed to the flange between the ionization vacuum sensing component and the MEMS capacitor film vacuum sensing component by bolts. The shielding plate is a composite heat insulation structure, including a non-magnetic stainless steel sheet as a substrate, the side of which facing the ionization vacuum sensing component is a mirror-like high-reflection surface; a heat insulation component composed of multiple layers of tantalum is fixed on the back of the substrate.

[0012] The wide-range vacuum gauge calibration tube with self-calibration function provided in this application has the following beneficial effects: This application enables the embedding of high-vacuum range vacuum reference standard instruments. Utilizing their excellent linearity and long-term stability, it achieves in-situ / online calibration of MEMS capacitive thin-film vacuum sensing components for medium and low vacuum ranges and ionization-type vacuum sensing components for high / ultra-high vacuum ranges. This avoids disassembly during periodic inspections, realizes self-calibration functionality, maintains the consistency of metrological characteristics during the traceability and transfer of wide-range vacuum gauges, and improves the accuracy and reliability of wide-range vacuum measurement. It also solves the prominent problems of low accuracy and severe response delay in existing wide-range composite vacuum gauges in overlapping areas. Attached Figure Description

[0013] The accompanying drawings, which form part of this application, are used to provide a further understanding of the application and to make other features, objects, and advantages of the application more apparent. The illustrative embodiments and descriptions of this application are used to explain the application and do not constitute an undue limitation of the application.

[0014] In the attached diagram: Figure 1 This is a schematic diagram of the structure of the recalibration tube of a wide-range vacuum gauge with self-calibration function according to an embodiment of this application; In the figure: 1-support rod, 2-measuring head, 3-rotor, 4-vacuum tube, 5-CF16 flange, 6-gate, 7-collector electrode, 8-vacuum chamber, 9-CF35 flange electrode, 10-cathode, 11-shielding plate, 12-MEMS capacitor film vacuum sensing component. Detailed Implementation

[0015] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0016] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0017] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0018] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0019] In addition, the term "multiple" should mean two or more.

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0021] like Figure 1 As shown, this application provides a wide-range vacuum gauge calibration tube with self-calibration function, including a magnetic levitation rotor vacuum sensing component, a vacuum chamber 8, an ionization type vacuum sensing component, and a MEMS capacitor film vacuum sensing component 12. The magnetic levitation rotor vacuum sensing component is disposed outside the vacuum chamber 8 and connected to the outer wall of the vacuum chamber 8 via a CF16 flange 5. The ionization type vacuum sensing component is disposed inside the vacuum chamber 8 and fixedly welded to a CF35 flange electrode 9 below the vacuum chamber 8. The MEMS capacitor film vacuum sensing component 12 is disposed below the ionization type vacuum sensing component and is isolated by a shielding plate 11.

[0022] Specifically, the wide-range vacuum gauge composite tube with self-calibration function provided in this application embodiment achieves in-situ / online calibration of the MEMS capacitive thin-film vacuum sensing component 12 corresponding to the medium and low vacuum range and the ionization vacuum sensing component in the high vacuum / ultra-high vacuum range by embedding the high vacuum range vacuum reference standard instrument—the magnetic levitation rotor vacuum sensing component. This solves the problems of poor measurement accuracy, frequent periodic disassembly and verification, and poor reliability of overlapping areas in existing wide-range composite vacuum gauges.

[0023] Furthermore, the magnetic levitation rotor vacuum sensing assembly includes a support rod 1, a measuring head 2, a rotor 3, and a vacuum tube 4, wherein: the support rod 1 is fixed on the housing of the assembly; the measuring head 2 is disposed between the support rods 1; the rotor 3 is suspended in the magnetic field generated by the measuring head 2 and is located inside the vacuum tube 4; the vacuum tube 4 is connected to the vacuum chamber 8 through a CF16 flange 5 to form an integral vacuum passage.

[0024] Furthermore, rotor 3 is a spherical rotor with a surface roughness ≤0.01μm and a ball diameter variation ≤0.08μm.

[0025] Furthermore, vacuum tube 4 is made of non-magnetic stainless steel with high electrical conductivity.

[0026] Specifically, the magnetic levitation rotor vacuum sensing assembly, as a high-vacuum range vacuum reference standard, is the core component for achieving self-calibration. It includes a support rod 1, a measuring head 2, a rotor 3, and a vacuum tube 4. The support rod 1 serves as a mechanical support structure, used to fix and install the measuring head 2 and ensure its relative position with the vacuum tube 4 is stable, guaranteeing the accuracy of the rotor 3's levitation position and preventing vibration or displacement from interfering with the measurement. The measuring head 2 contains structures such as electromagnetic coils and position sensors, used to generate an electromagnetic field to levitate and drive the rotor 3, achieving non-contact, high-precision vacuum measurement with good linearity and long-term stability. The rotor 3 is a spherical rotor with a surface roughness ≤0.01μm and a diameter variation ≤0.08μm. It levitates and rotates in the magnetic field generated by the measuring head 2. The rotational speed is affected by the resistance of surrounding gas molecules, and the vacuum pressure can be inferred by measuring the change in rotational speed. The vacuum tube 4 is made of high-conductivity non-magnetic stainless steel and serves as the working cavity for the rotor 3 and the measuring head 2. It is connected to the external vacuum chamber 8, providing a sealed vacuum environment while ensuring the penetration of the magnetic field and not affecting the levitation of the rotor 3.

[0027] Furthermore, the ionization-type vacuum sensing component includes a cathode 10, a grid 6, and a collector 7, wherein: the grid 6 is a squirrel cage structure closed at both ends, and the material is a platinum-iridium alloy; the collector 7 is located at the axial position of the grid 6 structure and is used to collect positive ions passing through the grid 6, and the material is a molybdenum wire; the cathode 10 is located on the outside of the grid 6, and the material is a yttrium-iridium oxide wire with a coating thickness ≤40μm.

[0028] Specifically, the ionization-type vacuum sensing component, used for measuring high vacuum and ultra-high vacuum ranges, consists of a thermionic ionization gauge structure composed of three electrodes: a cathode 10, a grid 6, and a collector 7. The cathode 10 emits electrons; when heated, the iridium filament coated with yttrium oxide emits thermionic electrons. The grid 6 accelerates and traps electrons, attracting electrons emitted from the cathode 10 and accelerating them to an energy sufficient to ionize gas molecules. These electrons oscillate back and forth within the space enclosed by the grid 6 wires, greatly increasing the path and probability of collisions with gas molecules. The overall structure employs a squirrel cage design with closed ends, effectively trapping electrons and improving ionization efficiency. The collector 7 collects ions; positively charged gas ions generated in the grid 6 region are attracted and trapped by the collector 7. The collector 7 collects the ion flow signal. Since the magnitude of the ion flow is proportional to the gas pressure, the current vacuum pressure can be calculated by measuring this tiny ion flow.

[0029] Furthermore, the reference cavity vacuum pressure of the MEMS capacitive thin-film vacuum sensing component 12 is ≤10. -3 The temperature drift of the inter-electrode capacitance is ≤0.01%FS, and the pressure is in the Pa range. The MEMS capacitive thin-film vacuum sensing component 12 is used as a sensing component for measurement in the medium and low vacuum range.

[0030] Furthermore, the shielding plate 11 is bolted to the flange between the ionization vacuum sensing component and the MEMS capacitor film vacuum sensing component 12. The shielding plate 11 is a composite thermal insulation structure, including a non-magnetic stainless steel sheet as a substrate, the side facing the ionization vacuum sensing component being a mirror-like high-reflectivity surface; a thermal insulation component composed of multiple layers of tantalum foil is fixed to the back of the substrate. The shielding plate 11 is fixed between the ionization vacuum sensing component and the MEMS capacitor film vacuum sensing component 12. Its mirror-like reflective layer can directly reflect most of the infrared thermal radiation back to the ionization gauge region, preventing heat from being transferred downwards in the form of radiation. At the same time, the multi-layer tantalum foil thermal insulation, through multiple layers of highly reflective, low-thermal-conductivity metal foil, greatly increases the thermal resistance, effectively suppressing heat transfer through a combination of conduction and radiation. Through this composite structure of reflection and thermal insulation, efficient thermal protection of the MEMS capacitor film vacuum sensing component 12 is achieved, ensuring that the accuracy of its temperature-sensitive inter-electrode capacitance measurement is not affected by the heat source above.

[0031] Specifically, the wide-range vacuum gauge recalibration tube with self-calibration function provided in this application embodiment, during use, in 10 -4 Pa~10 -3 Within the Pa range, the ionization-type vacuum sensing component was calibrated using a magnetically levitated rotor vacuum sensing component to obtain the calibration coefficient of the ionization-type vacuum sensing component; within 10... -1 Within the Pa~1Pa range, a magnetic levitation rotor vacuum sensing component was used to calibrate a MEMS capacitive thin-film vacuum sensing component, yielding the calibration coefficient of the MEMS capacitive thin-film vacuum sensing component. For example, in the range of 1.0325×10... -4 Pa ~ 9.1862 × 10 -3 The calibration factor is 1.025 within the Pa range; at 1.6870 × 10 -1 With a calibration coefficient of 1.005 and a range of Pa to 1.0295 Pa, this system enables in-situ / online calibration of the vacuum gauge's recalibration tube over a wide range.

[0032] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. 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.

Claims

1. A wide range gauge composite tube for a vacuum gauge having a self-calibration function, characterized by, The magnetic levitation rotor vacuum sensor assembly, the vacuum chamber, the ionization type vacuum sensor assembly and the MEMS capacitive diaphragm vacuum sensor assembly are provided. The magnetic levitation rotor vacuum sensor assembly is arranged outside the vacuum chamber and connected to the outer pipe wall of the vacuum chamber through a CF16 flange. The ionization type vacuum sensor assembly is arranged inside the vacuum chamber and fixedly welded to a CF35 flange electrode below the vacuum chamber. The MEMS capacitive diaphragm vacuum sensor assembly is arranged below the ionization type vacuum sensor assembly and isolated by a shielding plate.

2. The wide range gauge composite gauge tube with self-calibration function according to claim 1, characterized in that, The magnetic levitation rotor vacuum sensor assembly comprises a support rod, a measuring head, a rotor and a vacuum pipe. The support rod is fixed to the housing of the assembly. The measuring head is arranged between the support rods. The rotor is suspended in the magnetic field generated by the measuring head and located inside the vacuum pipe. The vacuum pipe is connected to the vacuum chamber through a CF16 flange to form an integrated vacuum passage.

3. The wide range gauge composite gauge tube with self-calibration function according to claim 2, characterized in that, The rotor is a spherical rotor with a surface roughness of ≤0.01 μm and a spherical diameter variation of ≤0.08 μm.

4. The wide range gauge composite gauge tube with self-calibration function according to claim 3, characterized in that, The vacuum pipe is made of high-conductivity non-magnetic stainless steel material.

5. The wide range gauge composite gauge tube with self-calibration function according to claim 4, characterized in that, The ionization type vacuum sensor assembly comprises a cathode, a grid and a collector. The grid is a squirrel cage structure with closed ends and made of platinum-iridium alloy. The collector is arranged at the axial position of the grid structure and used for collecting positive ions passing through the grid, and is made of molybdenum wire. The cathode is arranged outside the grid and made of yttrium-iridium wire with a coating layer thickness of ≤40 μm.

6. The wide range gauge composite gauge tube with self-calibration function according to claim 5, characterized in that, The vacuum pressure in the reference chamber of the MEMS capacitive diaphragm vacuum sensing assembly is less than or equal to 10 -3 The temperature drift of the inter-electrode capacitance is less than or equal to 0.01% FS.

7. The wide range gauge composite gauge tube with self-calibration function according to claim 6, characterized in that, The shielding plate is fixed to the flange plate between the ionization type vacuum sensor assembly and the MEMS capacitive diaphragm vacuum sensor assembly by bolts, and is a composite heat insulation structure comprising a non-magnetic stainless steel sheet as a base plate, one side of which facing the ionization type vacuum sensor assembly is a mirror high reflection surface, and a multilayer tantalum sheet heat insulation assembly is fixed to the back of the base plate.

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