Vacuum gauge, calibration method of vacuum gauge and vacuum measurement method

Abstract

The invention discloses a vacuum gauge, a calibration method of the vacuum gauge and a vacuum measurement method. The vacuum gauge comprises a shell, an impeller rotor, a rotation driving part and a controller. The shell is internally provided with a cavity and a connecting port formed by surrounding the edge of the shell; the connecting port is used for connecting a target cavity; the impeller rotor comprises a rotating shaft and is rotatably arranged in the cavity; one end of the rotating shaft faces the connector, and the other end of the rotating shaft is located at one end of the shell back to the connector; the rotary driving part is arranged at one end, back to the connecting port, of the shell, and a rotary output shaft of the rotary driving part is used for driving the rotary shaft to rotate through matching with the rotary shaft; and the controller is electrically connected with the rotary driving part and is configured to determine the vacuum degree of the target cavity based on the power of the rotary driving part. According to the vacuum gauge, the rotary driving part needs different powers to drive the impeller rotor to overcome resistance from gas under different vacuum degrees, the vacuum degree of the target cavity is measured, and the measuring range and accuracy of the vacuum gauge are improved.

Description

Technical Field

[0001] The present application relates to the field of vacuum technology, and in particular to a vacuum gauge, a vacuum gauge calibration method, and a vacuum measurement method. Background Art

[0002] A vacuum gauge is an instrument used to measure gas pressure below atmospheric pressure in a vacuum environment. Currently, different types of vacuum gauges are based on different physical principles and are generally only suitable for different vacuum scenarios.

[0003] For example: Mechanical vacuum gauges use the deformation or displacement of mechanical components to measure pressure, and determine pressure by measuring the deformation of elastic components under pressure. Thermal transfer vacuum gauges measure based on the relationship between the thermal conductivity of gases and pressure. Gas pressure is reflected by measuring the resistance change of a heated resistor wire. Ionization vacuum gauges use the ionization characteristics of gas molecules under the action of an electric field for measurement. Hot cathode ionization vacuum gauges emit electrons through the hot cathode, ionizing gas molecules and measuring the ion flow to determine pressure; cold cathode ionization vacuum gauges measure pressure through the adsorption and desorption of gas molecules in an electric field. Among these vacuum gauges, the use of mechanical vacuum gauges is limited to a specific vacuum range. Thermal transfer vacuum gauges and ionization vacuum gauges are limited by the type of gas.

[0004] In other words, currently, the commonly used vacuum gauges do not have a single vacuum gauge that can meet the needs of a wide range of applications. Summary of the Invention

[0005] The purpose of the present application is to provide a vacuum gauge, a vacuum gauge calibration method and a vacuum measurement method, in which the power of the rotating driving member is different according to the corresponding relationship between power and vacuum degree, and the vacuum degree of the target cavity can be determined, thereby expanding the scope of application of the vacuum gauge.

[0006] In the first aspect, the present application provides a vacuum gauge, comprising a shell, an impeller rotor, a rotating drive member and a controller; the shell has a chamber inside and a connection port formed by the edge of the shell; wherein the connection port is used for connecting to a target cavity; the impeller rotor includes a rotating shaft and is rotatably arranged in the chamber; one end of the rotating shaft faces the connection port, and the other end of the rotating shaft is located at an end of the shell facing away from the connection port; the rotating drive member is arranged at an end of the shell facing away from the connection port, and the rotating drive member is used to drive the rotating shaft to rotate by cooperating with the rotating shaft; the controller is electrically connected to the rotating drive member, and is configured to determine the vacuum degree of the target cavity based on the power of the rotating drive member.

[0007] The above-mentioned vacuum gauge is based on the fact that the rotation of the impeller rotor needs to overcome different resistance from the gas under different vacuum degrees, and the power of the rotating drive component is also different accordingly. The vacuum degree of the target cavity can be determined by the correspondence between power and vacuum degree, so that the vacuum gauge can measure almost the entire range of vacuum degrees and is not limited to the type of gas, thereby expanding the scope of application of the vacuum gauge. In combination with the first aspect, optionally, the impeller rotor further includes several stages of impellers; the several stages of impellers are arranged along the length direction of the rotating shaft and are connected to the rotating shaft; the impeller includes several blades, and the blades have a length direction and a width direction; wherein the length direction is consistent with the radial direction of the rotating shaft, and the width direction intersects with the length direction; the width direction of the blade of the stage farthest from the rotating drive member is obliquely intersected with the length direction of the rotating shaft; wherein, of the two angles formed by the oblique intersection near the connecting port, the one that is closer to the front of the rotation direction of the rotating shaft has an angle of a first acute angle; the width direction of the blade of the stage closest to the rotating drive member is obliquely intersected with the length direction of the rotating shaft; wherein, of the two angles formed by the oblique intersection near the connecting port, the one that is closer to the rear of the rotation direction of the rotating shaft has an angle of a second acute angle.

[0008] The aforementioned vacuum gauge balances the pressure between the internal chamber of the housing and the target cavity by designing the blades in the impeller furthest from the rotating drive element in an inclined manner. Furthermore, the reverse tilting of the blades in the impeller closest to the rotating drive element prevents, to a certain extent, the formation of vortices in the internal chamber of the housing and significant changes in local pressure, thereby optimizing the airflow within the chamber. Ultimately, the pressure difference between the pressure in the chamber and the pressure in the target cavity is reduced, which in turn improves the measurement accuracy of the vacuum gauge.

[0009] In combination with the first aspect, optionally, the first acute angle is equal to the second acute angle.

[0010] The above-mentioned vacuum gauge, based on the opposite inclination angles of the outermost impellers, is designed with their respective absolute inclination angles being consistent, so that the first-stage impeller closest to the rotating drive element can cooperate with the first-stage impeller closest to the connection port to the greatest extent, thereby optimizing the airflow inside the chamber, thereby further reducing the pressure difference between the pressure inside the chamber and the pressure inside the target chamber, and correspondingly further improving the measurement accuracy of the vacuum gauge.

[0011] In combination with the first aspect, optionally, the value range of the first acute angle includes [45°, 90°); and / or the value range of the second acute angle includes [45°, 90°).

[0012] The above-mentioned vacuum gauge limits the value range of the first acute angle and / or the second acute angle to [45°, 90°), so that the first-stage impeller and / or the last-stage impeller blades encounter less resistance during rotation, and the air volume generated during rotation is more suitable for balancing the pressure difference between the chamber and the target cavity, and optimizing the airflow in the chamber.

[0013] In combination with the first aspect, optionally, the width direction of the intermediate stage blades is parallel to the length direction of the rotating shaft; wherein, the intermediate stage blades are blades between the first stage impeller farthest from the rotating drive member and the first stage impeller closest to the rotating drive member.

[0014] The aforementioned vacuum gauge, by limiting the width direction of the intermediate-stage blades to be parallel to the length direction of the rotating shaft, ensures that the force exerted by gas molecules on the blades is perpendicular to the plane in which the blades lie. Accordingly, at the same rotational speed, the blades experience the greatest resistance from the air, requiring the rotary drive to drive the impeller rotor with a higher power or current. This amplifies the effect of air pressure on the power or current of the rotary drive, thereby further improving the measurement accuracy of the vacuum gauge. In a second aspect, the present application provides a vacuum gauge calibration method, wherein the vacuum gauge includes an impeller rotor, a rotary drive, and a controller; the method is applied to the controller; the method comprises: constructing an initial mathematical model between the power and vacuum level of the rotary drive; controlling the rotary drive to rotate at a fixed speed and collecting the power data and corresponding vacuum level data; and fitting the initial mathematical model using the power data and vacuum level data to obtain a calibration mathematical model; wherein the calibration mathematical model is used to determine the vacuum level of a target cavity based on the detected power of the rotary drive.

[0015] The above-mentioned vacuum gauge calibration method has the same beneficial effects as the first aspect or any optional implementation method of the first aspect, and will not be repeated here.

[0016] In a third aspect, the present application provides a method for measuring vacuum, which is applied to a controller in a vacuum gauge; wherein the vacuum gauge includes an impeller rotor, a rotating drive member and the controller; the method includes: obtaining the detected power of the rotating drive member; and using a pre-calibrated calibration mathematical model to calculate the vacuum degree of the target cavity based on the power; wherein the calibration mathematical model is obtained by the method described in the second aspect.

[0017] The above-mentioned vacuum measurement method has the same beneficial effects as the first aspect or any optional implementation of the first aspect, and will not be repeated here.

[0018] In combination with the third aspect, optionally, in the process of obtaining the calibration mathematical model, the rotating drive member is controlled to rotate at a fixed speed, and the power data and the corresponding vacuum data are collected, including: controlling the rotating drive member to rotate at a fixed speed under a fixed input voltage, and collecting the input current data and the corresponding vacuum data of the rotating drive member; in the process of obtaining the calibration mathematical model, the initial mathematical model is fitted with the power data and the vacuum data to obtain a calibration mathematical model, including: fitting the initial mathematical model with the input current data and the vacuum data to obtain a calibration mathematical model; using the pre-calibrated calibration mathematical model to calculate the vacuum degree of the target cavity according to the power, including: using the pre-calibrated calibration mathematical model to calculate the vacuum degree of the target cavity according to the detected current of the rotating drive member.

[0019] The above-mentioned vacuum measurement method calibrates the vacuum gauge by collecting current data and determines the vacuum degree of the target cavity by measuring the current data. Compared with calibrating the vacuum gauge by power data and determining the vacuum degree of the target cavity by power data, the parameters to be collected are single (only current data needs to be collected, and voltage data does not need to be collected), and the step of calculating power based on current and voltage is omitted, thereby saving computing resources and improving the response speed of the controller during the measurement process.

[0020] In combination with the third aspect, optionally, in the process of obtaining the calibration mathematical model, an initial mathematical model between the power and vacuum degree of the rotary drive member is constructed, including: dividing the range of the vacuum gauge into a low vacuum degree interval and a high vacuum degree interval; wherein the low vacuum degree interval is [10 5 Pa,10 -2 Pa], the high vacuum range is [10 -2 Pa,10 -5 Pa]; corresponding to the low vacuum interval, construct a first initial mathematical model; and corresponding to the high vacuum interval, construct a second initial mathematical model; wherein, the first initial mathematical model and the second initial mathematical model are respectively:

[0021] P vac =k1·P w

[0022] P vac =k2·P w

[0023] Where, P vac Characterize the vacuum degree, P w Characterizes the power of the rotating drive component, k1 and k2 are coefficients to be fitted.

[0024] The above-mentioned vacuum measurement method analyzes the resistance encountered by the blade during rotation for low vacuum and high vacuum respectively and derives the calculation formula, especially considering the different flow states of the gas caused by different vacuum degrees, and thus the different sources of the blade resistance, thereby more fully explaining that the current or power of the rotating drive and the vacuum degree are in a linear functional relationship within the corresponding vacuum degree range. Based on the different vacuum degrees, different linear functions are used as the initial mathematical model for fitting, which also takes into account the different vacuum degrees. The slope of the linear functional relationship between the current or power and the vacuum degree is also different, so that the final fitted calibration mathematical model is closer to the true relationship between the current or power and the vacuum degree, and ultimately further improves the accuracy of the vacuum gauge calibration, and correspondingly further improves the accuracy of the vacuum measurement.

[0025] In combination with the third aspect, optionally, in the process of obtaining the calibration mathematical model, the rotating drive member is controlled to rotate at a fixed speed, and the power data and the corresponding vacuum data are collected, including: controlling the rotating drive member to rotate at a first fixed speed, and collecting first power data and the corresponding first vacuum data; and controlling the rotating drive member to rotate at a second fixed speed, and collecting second power data and the corresponding second vacuum data; wherein, the first vacuum data is in a low vacuum range, the second vacuum data is in a high vacuum range, and the first fixed speed is less than the second fixed speed.

[0026] In the above vacuum measurement method, since the resistance of the gas to the blade is relatively small under high vacuum, the change in resistance is not obvious. Therefore, when measuring the vacuum degree based on the change in blade resistance, the change in blade resistance is difficult to capture. This will affect the accuracy of measuring the specific vacuum degree under high vacuum. However, by controlling the motor to rotate at a higher speed under high vacuum to calibrate the vacuum gauge, the coefficient (or slope) in the linear function relationship between current or power and vacuum degree can be changed, thereby amplifying the change in current or power caused by small changes in resistance, and ultimately further improving the measurement accuracy.

[0027] In summary, the vacuum gauge, vacuum gauge calibration method and vacuum measurement method provided by the present application are based on the fact that the rotation of the impeller rotor under different vacuum degrees needs to overcome different resistances from the gas, and the power of the rotating drive member is correspondingly different, thereby measuring the vacuum degree of the target cavity, so that the vacuum gauge can measure almost the entire range of vacuum degrees, and is not limited to the type of gas, thereby expanding the scope of application of the vacuum gauge. By designing the blades in the impeller farthest from the rotating drive member, the pressure between the internal chamber of the shell and the target cavity is balanced. On this basis, by designing the blades in the impeller closest to the rotating drive member in the opposite direction, the formation of vortices in the internal chamber of the shell and the significant changes in local pressure are prevented to a certain extent, thereby optimizing the airflow in the chamber. Ultimately, the pressure difference between the pressure in the chamber and the pressure in the target cavity is made smaller, which correspondingly improves the measurement accuracy of the vacuum gauge. By limiting the width direction of the intermediate blades to be parallel to the length direction of the rotating shaft, the force exerted by the gas molecules on the blades is perpendicular to the plane where the blades are located, which is equivalent to amplifying the effect of air pressure on the power or current of the rotating drive, thereby further improving the measurement accuracy of the vacuum gauge. In the process of pre-calibrating the vacuum gauge, this vacuum measurement method analyzes the resistance encountered by the blades during rotation for low vacuum and high vacuum degrees respectively and derives the calculation formula, which more fully illustrates that the current or power of the rotating drive and the vacuum degree are in a linear function relationship within the corresponding vacuum degree range. Based on the different vacuum degrees, different linear functions are used as the initial mathematical model for fitting, which further improves the accuracy of the vacuum gauge calibration and correspondingly further improves the accuracy of the vacuum measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 A cross-sectional view of a vacuum gauge provided in an embodiment of the present application;

[0030] Figure 2 A schematic diagram of the blade tilting method of the impeller rotor in the vacuum gauge provided in an embodiment of the present application;

[0031] Figure 3 A flow chart of a vacuum gauge calibration method provided in an embodiment of the present application;

[0032] Figure 4A flow chart of a vacuum measurement method provided in an embodiment of the present application;

[0033] Figure 5 This is a specific flow chart of step S120 during the vacuum gauge calibration process in the vacuum measurement method provided in an embodiment of the present application;

[0034] Figure 6 A schematic diagram illustrating the marking of various parameters on a blade during the calibration process of a vacuum gauge in the vacuum measurement method provided in an embodiment of the present application;

[0035] Figure 7 This is a specific flow chart of step S140 during the vacuum gauge calibration process in the vacuum measurement method provided in an embodiment of the present application.

[0036] Icons: 100, vacuum gauge; 110, housing; 111, connection port; 120, impeller rotor; 121, rotating shaft; 122, blades; 130, rotating drive component; 140, controller; 200, target cavity. DETAILED DESCRIPTION

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without making any creative efforts shall fall within the scope of protection of the present application.

[0039] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0040] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is typically placed when in use. These terms are intended only to facilitate the description of this application and simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting this application. Furthermore, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0041] Furthermore, terms such as "horizontal" and "vertical" do not necessarily mean that a component must be absolutely horizontal or overhanging, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but rather that it can be slightly tilted.

[0042] It should also be noted that, in the description of this application, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0043] Please refer to Figure 1 , Figure 1 : is a cross-sectional view of the vacuum gauge 100 provided in an embodiment of the present application. The vacuum gauge 100 provided in an embodiment of the present application may include a housing 110, an impeller rotor 120, a rotary drive member 130 and a controller 140. The housing 110 may have a chamber and a connection port 111 formed by the edge of the housing 110. The connection port 111 may be used for connection to the target cavity 200. The impeller rotor 120 may include a rotating shaft 121 and may be rotatably arranged in the chamber. One end of the rotating shaft 121 may face the connection port 111, and the other end of the rotating shaft 121 may be located at an end of the housing 110 that is away from the connection port 111. The rotary drive member 130 may be arranged at an end of the housing 110 that is away from the connection port 111, and the rotary output shaft of the rotary drive member 130 may be used to drive the rotating shaft to rotate 121 by cooperating with the rotating shaft 121. The controller 140 may be electrically connected to the rotary driver 130 and may be configured to determine the vacuum level of the target chamber 200 based on the power of the rotary driver 130 .

[0044] The shell 110 can be used to provide a relatively closed operating environment for the impeller rotor 120. The material of the shell 110 can be a high-density metal material such as stainless steel or aluminum alloy. In addition, the shell 110 can also have a certain corrosion resistance to cope with the corrosive gas that may exist in the target cavity 200. Specifically, an anti-corrosion layer can be sprayed on the inner wall of the shell 110, or a high-density metal material with anti-corrosion properties can be used. The connection port 111 on the shell 110 can adopt a detachable flange interface, for example: KF25 quick-release flange interface. The specific shape of the shell 110 can be a cylinder, and the internal chamber can also be a cylinder to facilitate the installation and rotation of the internal impeller rotor 120 and the internal gas flow.

[0045] The impeller rotor 120 may have multiple impeller stages or only one impeller stage. Each impeller stage may be composed of a plurality of blades 122. The impeller rotor 120 may be made of a high-strength, lightweight material to reduce the moment of inertia, thereby amplifying the effect of the different resistances overcome by the impeller rotor 120 during rotation due to different vacuum levels. Specifically, these materials may have the following properties: density <4.6 g / cm3, hardness >HB80, tensile strength >250 MPa, and yield strength >240 MPa. For example, titanium and titanium alloys, magnesium-lithium alloys, aluminum and aluminum alloys, and high-strength plastics all have these properties.

[0046] The multi-stage impellers and the rotating shaft 121 of the impeller rotor 120 can be integrally formed or separately formed and then assembled. Regarding separate forming, on the one hand, the rotating shaft 121 can be integrally formed using a mold, etc., and the multi-stage impeller rotor can also be integrally formed using a mold, etc., and then the integrally formed rotating shafts 121 and the multi-stage impeller rotor are assembled together to form the impeller rotor 120. On the other hand, the rotating shaft 121 can also be separately manufactured, with each stage of the impeller rotor separately manufactured, and finally the multi-stage impellers and the rotating shaft 121 are assembled together to form the impeller rotor 120. The impeller rotor 120 can be mounted in the chamber via high-speed bearings. Specifically, both ends of the rotating shaft 121 of the impeller rotor 120 can be connected to high-speed bearings disposed in the chamber. The high-speed bearings can be located within the housing 110 near the connection port 111 and at the end of the housing 110 facing away from the connection port 111. The high-speed bearing located within the housing 110 near the connection port 111 can be a non-contact permanent magnet bearing. The permanent magnetic bearing is beneficial to the cleanliness between the rotating shaft 121 and the bearing and reduces friction resistance. The high-speed bearing at the end of the housing 110 facing away from the connecting port 111 can specifically be a high-speed mechanical bearing to ensure the stability of the impeller rotor 120 at high speed.

[0047] In the embodiment of the present application, the rotary drive member 130 includes at least the following two optional specific implementations:

[0048] The first is to use the housing 110 and the magnetic elements provided on the inner wall of the housing 110 as the rotating drive element 130, which is used to drive the rotating shaft 121 and drive the entire impeller rotor 120 to rotate. In this case, a Hall effect-free drive method is achieved. Among them, the housing 110 and the magnetic elements provided on the inner wall of the housing 110 are equivalent to the stator of the motor, and the rotating shaft 121 connected to the impeller rotor 120 is equivalent to the rotor of the motor.

[0049] The second method is to set a motor as the rotation drive member 130 at the end of the housing 110 facing away from the connection port. The motor can be an AC motor or a DC motor, etc. Preferably, the rotation drive member 130 can be a high-speed motor.

[0050] Typically, the higher the speed of the impeller rotor 120, the greater the resistance it encounters from the gas. Therefore, as a preferred embodiment, during vacuum measurement, the vacuum gauge 100 provided in the embodiment of the present application can rotate the rotary drive member 130 at high speed, thereby subjecting the impeller rotor 120 to greater resistance, thereby amplifying the effect of vacuum degree (or pressure) on the power of the rotary drive member 130 and improving the measurement accuracy of the vacuum gauge 100.

[0051] The controller 140 can be a microprocessor, a digital signal processor, a programmable logic controller, a field programmable gate array, etc. The controller 140 can control the operation of the rotary drive member 130 based on the user's operation or a preset program. The controller 140 can also determine the vacuum of the target cavity 200 based on the power of the rotary drive member 130 obtained. The specific method can be that based on the different vacuum levels of the target cavity 200, the gas resistance encountered by the impeller rotor 120 during the rotation at the same speed is correspondingly different, and the power of the rotary drive member 130 is also different. According to the corresponding relationship between the power of the rotary drive member 130 and the vacuum level, the vacuum level in the target cavity 200 is determined. The power of the rotary drive member 130 is different, and this can be achieved by keeping the voltage output thereto unchanged and changing the current output thereto.

[0052] Optionally, the vacuum gauge 100 provided in the embodiment of the present application may further include a display screen, such as a digital display screen or an LED display screen, etc., for displaying information such as measurement results, the calculation process of the vacuum degree, and the power of the rotary drive member 130 .

[0053] During the above implementation process, based on the different vacuum degrees, the rotation of the impeller rotor 120 needs to overcome different resistances from the gas, and the power of the rotating drive 130 is also different accordingly. Then, the vacuum degree of the target cavity 200 can be determined through the correspondence between power and vacuum degree, so that the vacuum gauge 100 can measure almost the entire range of vacuum degrees, and is not limited to the type of gas, thereby expanding the scope of application of the vacuum gauge 100.

[0054] Please refer to Figure 2 , Figure 2 Schematic diagram of the inclination of the blades 122 of the impeller rotor 120 in the vacuum gauge 100 provided in an embodiment of the present application. In some optional embodiments, the impeller rotor 120 may further include several stages of impellers. Several stages of impellers may be arranged along the length direction of the rotating shaft 121 and connected to the rotating shaft 121. The impeller may include several blades 122, and the blades 122 may have a length direction and a width direction. Among them, the length direction may be radially consistent with the rotating shaft 121, and the width direction may intersect with the length direction. The width direction of the first-stage blade 122 farthest from the rotating drive member 130 may be oblique to the length direction of the rotating shaft 121. Among them, of the two angles formed by the oblique intersection near the connecting port 111, the angle that is closer to the rotation direction of the rotating shaft 121 may be a first acute angle. The width direction of the first-stage blade 122 closest to the rotating drive member 130 may be oblique to the length direction of the rotating shaft 121. Among the two included angles formed by the oblique intersection close to the connecting port 111 , the angle of the one that is farther back than the rotation direction of the rotating shaft 121 may be a second acute angle.

[0055] For example, the impeller rotor 120 includes five stages of impellers, and the number of blades 122 of each stage of impellers is 22, 23, 24 or 25, etc. Then the impeller closest to the connection port 111, or the impeller farthest from the rotating drive member 130, can be regarded as the first-stage impeller. The impeller closest to the rotating drive member 130, or the impeller farthest from the connection port 111, can be regarded as the fifth-stage impeller or the last-stage impeller. The impellers between the first-stage impeller and the fifth-stage impeller are regarded as the second-stage impeller, the third-stage impeller, and the fourth-stage impeller, respectively. Generally, when the width direction of the blade 122 is parallel to the length direction of the rotating shaft 121, the resistance of the gas molecules to the blade 122 is almost vertical. Accordingly, during the rotation of the impeller, the resistance experienced by the blade 122 is relatively the largest.

[0056] Since the rotation of the blades 122 in the internal chamber of the housing 110 will cause the pressure in the chamber to be lower than the pressure of the target chamber 200, the pressure between the internal chamber of the housing 110 and the target chamber 200 can be balanced by the tilt design of the blades 122 in the first stage impeller to minimize the pressure difference between them. Figure 2The impeller at the top can be used as a first-stage impeller, in which the shape of the blades 122 can be rectangular. Figure 2 The thicker oblique line in the middle indicates that the blade 122 rotates so that its length direction is perpendicular to the plane of the picture. At both ends of the blade 122 in the length direction (one end is connected to the rotating shaft 121 and the other end is the end), the end faces away from the rotating shaft 121. Figure 2 The viewing direction shown is that the end connected to the shaft 121 faces the viewing direction. The width direction of the blade 122 and the length direction of the shaft 121 are obliquely intersected, usually with four angles, the two angles relatively close to the top (that is, close to the connection port 111) are complementary, and the two angles relatively close to the bottom (that is, close to the rotary drive member 130) are also complementary. The rotation direction is Figure 2 In the case of the direction indicated by the middle arrow, the two relatively upper angles are located on the left and right sides of the rotating shaft 121 respectively. With reference to the direction of rotation, one of them is closer to the front and the other is closer to the back. Then in the embodiment of the present application, the one closer to the front is an acute angle, and the one closer to the back is correspondingly an obtuse angle. When the blades 122 of the first-stage impeller are tilted to balance the pressure between the internal chamber of the shell 110 and the target chamber 200, the impeller at the lower end can be used as the last-stage impeller, and its tilt direction can be opposite to the tilt direction of the first impeller. It is used to cooperate with the first-stage impeller to prevent the formation of vortices and changes in local pressure in the internal chamber of the shell 110, thereby optimizing the gas flow in the gas chamber.

[0057] Of course, in the embodiment of the present application, the impeller rotor 120 may include at least two stages of impellers, namely, a first-stage impeller and a last-stage impeller, with the blades 122 in these two stages tilted in opposite directions. The impeller rotor 120 may also include three, four, or six stages of impellers, etc. The blades between the first-stage impeller and the last-stage impeller may be slightly tilted in the same direction as the first-stage or last-stage impellers, or may be non-tilted, meaning that the plane of the blades is parallel to the length of the shaft.

[0058] As a preferred embodiment, the spacing between the impellers of each stage in the length direction of the rotating shaft 121 can be as small as possible to make the pressure difference between the pressure in the chamber and the pressure in the target cavity 200 smaller. In the above implementation process, the pressure between the internal chamber of the shell 110 and the target cavity 200 is balanced by the inclined design of the blades 122 in the impeller at the farthest level from the rotating drive member 130. On this basis, the reverse inclination design of the blades 122 in the impeller at the closest level to the rotating drive member 130 prevents the formation of vortices in the internal chamber of the shell 110 and the occurrence of significant changes in local pressure to a certain extent, thereby optimizing the airflow in the chamber. Ultimately, the pressure difference between the pressure in the chamber and the pressure in the target cavity 200 is made smaller, which correspondingly improves the measurement accuracy of the vacuum gauge 100.

[0059] Please continue to refer to Figure 2 In some optional embodiments, the first acute angle and the second acute angle may be equal.

[0060] That is, the blades 122 in the first-stage impeller and the blades 122 in the last-stage impeller are inclined in opposite directions, but their respective absolute inclination angles are consistent.

[0061] During the above-mentioned implementation process, based on the opposite inclination angles of the outermost impellers, the design of their respective absolute inclination angles is consistent, so that the first-stage impeller closest to the rotating drive member 130 can cooperate with the first-stage impeller closest to the connecting port 111 to the greatest extent, thereby optimizing the airflow inside the chamber, thereby further reducing the pressure difference between the pressure inside the chamber and the pressure inside the target cavity 200, and correspondingly further improving the measurement accuracy of the vacuum gauge 100.

[0062] Referring to the figure, in some optional embodiments, the value range of the first acute angle may include [45°, 90°), and / or the value range of the second acute angle may include [45°, 90°), that is, greater than or equal to 45° and less than 90°.

[0063] Combined with the previously described tilt of blades 122 in the first-stage impeller, the impeller rotor 120 produces an effect of extracting air from the target cavity 200 during operation. When the first acute angle is 45°, the 45° angle of attack is aerodynamically closest to the optimal lift-to-drag ratio, effectively pushing air without excessively increasing drag. That is, when the first acute angle is less than 45°, the angle between the direction of the resistance exerted by air molecules on the blades 122 and the normal to the blades 122 gradually decreases, resulting in an increase in the air resistance experienced by the blades 122 during rotation. When the first acute angle is 60°, the air volume at the same speed is slightly lower than that at 45°, but the resistance to be overcome during operation is also relatively small. When the first acute angle is 90° (of course, the first acute angle in the embodiments of the present application does not include 90°), the plane of the blades 122 is nearly perpendicular to the rotating shaft 121, and the impeller rotor 120 generates virtually no axial airflow during rotation.

[0064] When the values of the second acute angle are 45°, 60° and 90° respectively (the value of the second acute angle in the embodiment of the present application does not include 90°), the effect and principle are similar to those of the first acute angle.

[0065] In the above implementation process, by limiting the value range of the first acute angle and / or the second acute angle to [45°, 90°), the first-stage impeller and / or the last-stage impeller blades 122 are subjected to less resistance during rotation, and the air volume generated during rotation is more suitable for balancing the pressure difference between the chamber and the target cavity 200, as well as optimizing the airflow in the chamber.

[0066] Please continue to refer to Figure 2 In some optional embodiments, the width direction of the intermediate blades 122 may be parallel to the length direction of the rotating shaft 121. The intermediate blades 122 may be blades 122 between the first-stage impeller farthest from the rotary drive member 130 and the first-stage impeller closest to the rotary drive member 130.

[0067] Combined with the description of the previous embodiment, in the embodiment of the present application, the inclination angle of the intermediate-stage blades 122 is 0. In this case, the normal direction of the plane on which the blades 122 are located is tangent to the direction of rotation of the impeller, that is, the force exerted by the gas molecules on the blades 122 is perpendicular to the plane on which the blades 122 are located.

[0068] In the above implementation, by aligning the width of intermediate blades 122 parallel to the length of rotating shaft 121, the force exerted by gas molecules on blades 122 is perpendicular to the plane in which blades 122 lie. Consequently, at the same rotational speed, blades 122 experience the greatest resistance from the air, requiring rotary drive 130 to drive impeller rotor 120 with greater power or current. This effectively amplifies the effect of air pressure on the power or current of rotary drive 130, further improving the measurement accuracy of vacuum gauge 100.

[0069] Please refer to Figure 3 , Figure 3 This is a flow chart of a vacuum gauge calibration method provided in an embodiment of the present application. Based on the same concept, an embodiment of the present application provides a vacuum gauge calibration method. The vacuum gauge may include an impeller rotor, a rotating drive member, and a controller, and the method may be specifically applied to the controller.

[0070] It is worth mentioning that the vacuum gauge 100 provided in the previous embodiments of the present application can be adapted to the calibration method provided in the embodiments of the present application, and can also be adapted to other theoretically executable methods.

[0071] In the embodiment of the present application, the specific structure of the vacuum gauge may be the same as that described in the previous embodiment.

[0072] The method may include:

[0073] Step S120: constructing an initial mathematical model between the power of the rotary drive component and the vacuum degree.

[0074] In the above step S120, since the pressure in the target cavity changes, the resistance encountered by the rotating impeller rotor will also change accordingly. In addition, high air pressure (low vacuum) means that there are more molecules inside the gas, the resistance acting on the blades is greater, and the power of the rotating drive component is greater; low air pressure (high vacuum) means that the gas molecules are sparse and the number of molecules is small, the force acting on the blades is smaller, and the power of the rotating drive component is smaller. Therefore, there is a one-to-one correspondence between the power of the rotating drive component and the vacuum degree. The specific corresponding relationship can be determined by those skilled in the art based on experience, or can be deduced based on theoretical knowledge in this field, or can be determined based on historical experimental data, etc. The embodiment of the present application does not impose specific restrictions on this. In a specific embodiment, based on the determined corresponding relationship, an initial mathematical model can be constructed. Specifically, it can be:

[0075] P vac =F(P w )

[0076] Where, P vac Characterize the vacuum degree, P w Characterizes the power of the rotating drive component, F is a function.

[0077] Step S140: controlling the rotary drive component to rotate at a fixed speed, and collecting power data and corresponding vacuum degree data.

[0078] In step S140 , the rotary drive member may rotate at a high speed, for example, 300-1500 Hz. Power data may be determined by measuring current and voltage. Vacuum data may be determined by measuring the vacuum level within the target cavity using a conventional vacuum gauge, such as a vacuum gauge, while the rotary drive member is rotating.

[0079] Step S160: fitting the initial mathematical model using the power data and the vacuum degree data to obtain a calibrated mathematical model.

[0080] In step S160, the parameters of the initial mathematical model are determined by fitting the collected power data and vacuum data, thereby obtaining a calibrated mathematical model for vacuum measurement. The calibrated mathematical model can determine the vacuum level of the target cavity based on the detected power of the rotary drive element.

[0081] In the above implementation, based on the one-to-one correspondence between the power of the rotary drive element and the vacuum level, the power data of the rotary drive element and the corresponding vacuum level data are collected and fitted to obtain a calibration mathematical model for measuring the vacuum level. This calibration mathematical model is then used to measure the vacuum level, thereby improving measurement accuracy. Other principles and beneficial effects are the same as those of the vacuum gauge described above and will not be further elaborated here.

[0082] Please refer to Figure 4 , Figure 4 Flowchart of a vacuum measurement method provided in an embodiment of the present application. Based on the same concept, an embodiment of the present application provides a vacuum measurement method, which is applied to a controller in a vacuum gauge. The vacuum gauge may include an impeller rotor, a rotating drive member, and a controller.

[0083] It is worth mentioning that the vacuum gauge 100 provided in the previous embodiments of the present application can be adapted to the measurement method provided in the embodiments of the present application, and can also be adapted to other theoretically executable methods.

[0084] The method may include:

[0085] Step S220: Acquire the detected power of the rotating drive component.

[0086] In step S220, the rotary drive element in the vacuum gauge may be controlled to rotate. The rotation frequency may be 300-1500 Hz. The power of the rotary drive element may also be obtained by measuring current and voltage.

[0087] Step S240: Calculate the vacuum degree of the target cavity according to the power using a pre-calibrated calibration mathematical model.

[0088] In the above step S240 , the calibration mathematical model is obtained by the vacuum gauge calibration method described above.

[0089] The above implementation process can be the same as the calibration method of the vacuum gauge described above, and will not be repeated here.

[0090] As some optional implementations, in the process of obtaining the calibration mathematical model, step S140 may include:

[0091] Step S141: controlling the rotary drive component to rotate at a fixed speed under a fixed input voltage, and collecting input current data of the rotary drive component and corresponding vacuum degree data.

[0092] In the above step S141, the power of the rotary drive member can be changed by fixing the input voltage, for example, 24V, and changing the input current. The input current of the rotary drive member can be specifically 0.01-4A.

[0093] Accordingly, in the process of obtaining the calibration mathematical model, step S160 may include:

[0094] Step S161: fitting the initial mathematical model using the input current data and the vacuum degree data to obtain a calibrated mathematical model.

[0095] In the above step S161, the initial mathematical model can be evolved into:

[0096] P vac =F(I)

[0097] Where, P vac represents the vacuum degree, I represents the current of the rotating drive part, and F is a function.

[0098] Accordingly, step S240 may include:

[0099] Step S241: using a pre-calibrated calibration mathematical model, the vacuum degree of the target cavity is calculated according to the detected current of the rotating drive component.

[0100] In the above step S241 , when the vacuum gauge is calibrated with current data and corresponding vacuum degree data, the vacuum degree of the target cavity can be determined by measuring the current of the rotating drive member during the process of measuring the vacuum degree.

[0101] In the above implementation process, the vacuum gauge is calibrated by collecting current data, and the vacuum degree of the target cavity is determined by measuring the current data. Compared with calibrating the vacuum gauge by power data and determining the vacuum degree of the target cavity by power data, the parameters to be collected are single (only current data needs to be collected, and voltage data does not need to be collected), and the step of calculating power based on current and voltage is omitted, thereby saving computing resources and improving the response speed of the controller during the measurement process.

[0102] Please refer to Figure 5 , Figure 5 This is a specific flow chart of step S120 during the vacuum gauge calibration process in the vacuum measurement method provided in the embodiment of the present application. As some optional implementations, in the process of obtaining the calibration mathematical model, step S120 may include:

[0103] Step S121: Divide the measuring range of the vacuum gauge into a low vacuum range and a high vacuum range.

[0104] In the above step S121, under a vacuum environment, the flow state of the gas can be divided into three types: turbulent flow, viscous flow, and molecular flow. The relationship between the three flow states and the vacuum degree is as follows:

[0105] Turbulence: It usually occurs in the rough vacuum stage, that is, the stage with higher pressure. The frequency of collisions between gas molecules is very high, the streamlines are disordered, and there are a large number of vortices.

[0106] Viscous flow: In the medium vacuum range, the mean free path of gas molecules is much smaller than the minimum cross-sectional dimension of the conduit, and the flow is mainly affected by the viscosity of the gas.

[0107] Molecular flow: In high vacuum and ultra-high vacuum conditions, the mean free path of gas molecules is much larger than the maximum cross-sectional dimension of the conduit, and there are very few collisions between molecules, which mainly collide with the wall.

[0108] Therefore, the vacuum degree can be divided according to the flow state of the above-mentioned gas. In the embodiment of the present application, the low vacuum degree interval is [10 5 Pa,10 -2 Pa], the high vacuum range is [10 -2 Pa,10 -5 Pa].

[0109] Accordingly, in the process of collecting data by controlling the operation of the rotary drive member, the vacuum degree can be divided into three intervals, and the corresponding relevant data are shown in Table 1.

[0110] Table 1

[0111]

[0112] It is worth mentioning that the low vacuum degree and high vacuum degree divided in the embodiment of the present application are used to construct the mathematical model in the subsequent steps, and the vacuum degree division in the above Table 1 is used to determine the parameters related to the operation of the rotating drive parts in the vacuum gauge during the data acquisition stage.

[0113] Step S122: corresponding to the low vacuum range, constructing a first initial mathematical model.

[0114] Step S123: corresponding to the high vacuum range, constructing a second initial mathematical model.

[0115] In the above steps S122 and S123, under low vacuum conditions, the gas flow state is mainly turbulent flow and viscous flow. Therefore, when calculating the relationship between current and vacuum, the inertial resistance of the rotor itself is mainly considered.

[0116] Please refer to Figure 6 , Figure 6 This is a schematic diagram of the marking of various parameters on the blade during the vacuum gauge calibration process in the vacuum measurement method provided in the embodiment of the present application. Figure 6 The air resistance of the blade unit (dr) divided in is:

[0117]

[0118] In the formula, F d is the air resistance, v is the speed of the blade relative to the air, C d is the air resistance coefficient, A is the projected area perpendicular to the direction of movement, and θ is the inclination angle of the blade, which is the first acute angle and the second acute angle described in the previous embodiment of the vacuum gauge.

[0119] Differentiating the above formula, the air resistance of the unit area (ds) corresponding to the blade unit is:

[0120]

[0121] Where ρ is the air density, ω is the rotation speed of the blade, and h is Figure 6 The width of the blade shown in Figure 6 The length of the blade unit shown in .

[0122] The air resistance moment of the unit area (ds) corresponding to the blade unit is:

[0123]

[0124] Integrate the drag torque over the entire blade surface:

[0125]

[0126] Where r1 is the rotation radius of the blade close to the shaft, and r2 is the rotation radius of the blade away from the shaft.

[0127] The power of the rotating drive is:

[0128] P w =μTω=UI

[0129] Where μ is a constant, T is the aforementioned resistance torque, and P w is the power of the rotating drive. In the case where the units of torque, speed and power are Nm, rad / s and w respectively, μ in the embodiment of the present application can be taken as U is the voltage of the rotating drive element.

[0130] According to the above power formula, the current is:

[0131]

[0132] Combined with the ideal gas state equation:

[0133]

[0134] Where M is the molar mass, P is vac is the gas pressure (vacuum degree), R is the molar gas constant, and K is the gas thermodynamic temperature.

[0135] Combining the equation about current obtained above, the relationship between current and vacuum degree can be obtained as follows:

[0136]

[0137] Remove P from the right side of the equation vac Taking all parameters except for , as a whole, it can be seen that the relationship between current and vacuum degree is a linear function. Correspondingly, the relationship between power and vacuum degree is also a linear function. Therefore, the first initial mathematical model can be:

[0138] P vac =k1·P w

[0139] Where k1 is the coefficient to be fitted.

[0140] It is worth mentioning that the mathematical model derived from the above reasoning is based on the case of only one blade. However, in the case of a multi-stage impeller with multiple blades in each stage, the vacuum gauge can also be calibrated based on the first mathematical model mentioned above, even if the inclination angles of all the blades are different. The reason is that the resistance of the entire impeller rotor can be the sum of the resistances of each blade. Furthermore, even if the inclination angles of each blade are different, it will only result in the right side of the above equation excluding P. vac All parameters other than P are considered as a whole parameter, but based on the multiplication distribution law or multiplication associative law in mathematics, P vac Extract it, then add up all the coefficients. Finally, take these added coefficients as a whole, and the relationship between current and vacuum degree is still a linear function.

[0141] Under high vacuum, the flow state of gas is mainly molecular flow. It is mainly based on the theory of gas molecular kinetics, considering the mean free path of gas molecules, collision frequency, and interaction with the tube wall.

[0142] Under high vacuum conditions, the mean free path of gas molecules is much larger than the maximum cross-sectional dimension of the conduit. Assuming there are no collisions between gas molecules before they collide with the blade surface, let the relative velocity of the gas molecules with the rotor before collision be V1 and the relative velocity after collision be V2. Then, V1t and V2t are the normal velocity components of the gas molecules relative to the blade before and after collision.

[0143] When the rotor is not rotating, the average normal velocity of the gas molecules after colliding with the rotor wall is V1t=0; when the rotor rotates at a speed of ω, due to relative motion, the average normal velocity is:

[0144] V 1t =ωrcosθ

[0145] Where ω is the blade's rotational speed, θ is the blade's inclination angle, which is the first and second acute angles described in the previous vacuum gauge embodiment. r is the distance from the blade's main axis to the blade's calculation position.

[0146] The damping of gas molecules is determined by the normal momentum transfer between gas molecules and blades, so the normal momentum transfer coefficient σ can be introduced:

[0147]

[0148] In general, when gas molecules collide with blade teeth, they are adsorbed on the surface and stay there for a while before being emitted. Therefore, V2t is approximately 0, and σ is approximately 1. Then we have:

[0149] m(V 1t -V 2t )=σmV 1t

[0150] Where m is the mass of a single gas molecule.

[0151] The number of molecules that collide with the rotor wall per unit area per unit time is:

[0152]

[0153] Where ν is the number of molecules, c is the average thermal motion speed of gas molecules, n is the number density of gas molecules, and T is the gas temperature.

[0154] The average normal momentum per unit area of the blade obtained from the gas molecules per unit time is:

[0155] ΔmV=νσmV 1t

[0156] The average momentum transfer per unit time on the blade unit area ds is:

[0157] dmV=ΔmV×ds=νσmV 1t ds

[0158] According to the momentum theorem, the average momentum transfer per unit time Δt is:

[0159]

[0160] Therefore, the resistance exerted by the gas molecules on the blade area ds is:

[0161]

[0162] Combine Figure 1 , where ds = hdr, V 1t =ωr cosθ, where h is the width of the blade. Substituting the two formulas here into the above resistance formula yields:

[0163]

[0164] Where, P vac is the gas pressure (vacuum degree).

[0165] The resistance torque generated by this resistance is:

[0166]

[0167] Where T is the resistance torque.

[0168] Integrating the drag torque over the entire blade surface yields:

[0169]

[0170] In the formula, r1 is the rotation radius of the blade close to the shaft, and r2 is the rotation radius of the blade away from the shaft. It can be seen that under high vacuum, the resistance torque T is proportional to the vacuum degree P. vac It also presents a linear function relationship.

[0171] Furthermore, combined with the motor power formula:

[0172] P w =μTω=UI

[0173] Where μ is a constant, T is the aforementioned resistance torque, ω is the rotation speed of the blade, and Pw is the power of the rotating drive. When the units of torque, speed, and power are Nm, rad / s, and w, respectively, μ in the embodiment of the present application can be taken as U is the voltage of the rotating drive element.

[0174] Finally, the current increment caused by the resistance torque is:

[0175]

[0176] Similarly, remove P from the right side of the equation. vac Taking all parameters except for as a whole, it can be seen that the relationship between current and vacuum degree is a linear function. Correspondingly, the relationship between power and vacuum degree is also a linear function. Therefore, the second initial mathematical model can be:

[0177] P vac =k2·P w

[0178] In the formula, k2 is the coefficient to be fitted.

[0179] Combined with the above description that the vacuum gauges of several blades can be calibrated under low vacuum conditions by constructing a first initial mathematical model based on a linear function, when several blades face high vacuum conditions, they can also be calibrated based on the above second initial mathematical model.

[0180] In the above implementation process, by analyzing the resistance encountered by the blades during rotation for low vacuum and high vacuum respectively and deriving the calculation formula, the different flow states of the gas caused by different vacuum degrees are especially taken into account, and thus the sources of the resistance of the blades are also different, thereby more fully explaining that the current or power of the rotating drive and the vacuum degree are in a linear function relationship within the corresponding vacuum degree range. Based on the different vacuum degrees, different linear functions are used as the initial mathematical model for fitting, which also takes into account the different vacuum degrees. The slope of the linear function relationship between the current or power and the vacuum degree is also different, so that the final fitted calibration mathematical model is closer to the true relationship between the current or power and the vacuum degree, and ultimately further improves the accuracy of the vacuum gauge calibration, and correspondingly further improves the accuracy of the vacuum measurement.

[0181] Please refer to Figure 7 , Figure 7 This is a specific flow chart of step S140 in the vacuum gauge calibration process in the vacuum measurement method provided in the embodiment of the present application. As some optional implementations, in the process of obtaining the calibration mathematical model, step S140 may include:

[0182] Step S142: controlling the rotary driving member to rotate at a first fixed speed, and collecting first power data and corresponding first vacuum degree data.

[0183] Step S143: controlling the rotary driving member to rotate at a second fixed speed, and collecting second power data and corresponding second vacuum degree data.

[0184] In the above steps S142 and S143, the first vacuum degree data is in the low vacuum degree range, the second vacuum degree data is in the high vacuum degree range, and the first fixed speed is lower than the second fixed speed. In other words, during the calibration process, the higher the vacuum degree, the higher the motor speed.

[0185] In the above implementation process, since the resistance of the gas to the blade is relatively small under high vacuum, the change in resistance is not obvious. Therefore, when measuring the vacuum degree based on the change in blade resistance, the change in blade resistance is difficult to capture. This will affect the accuracy of measuring the specific vacuum degree under high vacuum. However, by controlling the motor to rotate at a higher speed under high vacuum to calibrate the vacuum gauge, combined with the previous derivation process, the coefficient (or slope) in the linear function relationship between current or power and vacuum degree can be changed, thereby amplifying the change in current or power caused by the slight change in resistance, and ultimately further improving the measurement accuracy.

[0186] As an optional implementation, the mathematical model can be constructed and fitted in conjunction with the two vacuum degree intervals previously divided. The previously divided high vacuum or low vacuum can also be further divided. Thus, the initial mathematical models within the high vacuum and low vacuum levels are fitted in sections. Specifically, taking low vacuum as an example, it is further divided into a first low vacuum level and a second low vacuum level. In conjunction with the first initial mathematical model, fitting is performed within the first low vacuum level and the second low vacuum level, respectively. The resulting coefficient k1 to be fitted is typically two values.

[0187] By performing the segmented fitting on the initial mathematical model corresponding to the high vacuum degree or the low vacuum degree, the accuracy of the vacuum measurement is further improved.

[0188] In summary, the vacuum gauge, vacuum gauge calibration method and vacuum measurement method provided by each embodiment of the present application are based on the fact that the rotation of the impeller rotor under different vacuum degrees needs to overcome different resistance from the gas, and the power of the rotating drive member is correspondingly different, thereby measuring the vacuum degree of the target cavity, so that the vacuum gauge can measure almost the entire range of vacuum degrees, and is not limited to the type of gas, thereby expanding the scope of application of the vacuum gauge. By designing the blades in the impeller farthest from the rotating drive member, the pressure between the internal chamber of the shell and the target cavity is balanced. On this basis, by designing the blades in the impeller closest to the rotating drive member in the opposite direction, the formation of vortices in the internal chamber of the shell and the significant change in local pressure are prevented to a certain extent, thereby optimizing the airflow in the chamber. Ultimately, the pressure difference between the pressure in the chamber and the pressure in the target cavity is made smaller, which correspondingly improves the measurement accuracy of the vacuum gauge. By limiting the width direction of the intermediate blades to be parallel to the length direction of the rotating shaft, the force exerted by the gas molecules on the blades is perpendicular to the plane where the blades are located, which is equivalent to amplifying the effect of air pressure on the power or current of the rotating drive, thereby further improving the measurement accuracy of the vacuum gauge. In the process of pre-calibrating the vacuum gauge, this vacuum measurement method analyzes the resistance encountered by the blades during rotation for low vacuum and high vacuum degrees respectively and derives the calculation formula, which more fully illustrates that the current or power of the rotating drive and the vacuum degree are in a linear function relationship within the corresponding vacuum degree range. Based on the different vacuum degrees, different linear functions are used as the initial mathematical model for fitting, which further improves the accuracy of the vacuum gauge calibration and correspondingly further improves the accuracy of the vacuum measurement.

[0189] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A vacuum gauge, characterized in that: It includes a housing, an impeller rotor, a rotary drive member and a controller; The shell has a chamber inside and a connection port formed by the edge of the shell; wherein the connection port is used for connection to the target cavity; The impeller rotor includes a rotating shaft and is rotatably disposed within the chamber; One end of the rotating shaft faces the connecting port, and the other end of the rotating shaft is located at an end of the housing facing away from the connecting port; The rotary drive member is provided at an end of the housing facing away from the connecting port, and is used to drive the rotating shaft to rotate by cooperating with the rotating shaft; The controller is electrically connected to the rotary driving member and is configured to determine the vacuum degree of the target cavity based on the power of the rotary driving member.

2. The vacuum gauge according to claim 1, wherein The impeller rotor also includes several stages of impellers; The plurality of stages of impellers are arranged along the length direction of the rotating shaft and connected to the rotating shaft; The impeller includes a plurality of blades, each blade having a length direction and a width direction; wherein the length direction is consistent with the radial direction of the rotating shaft, and the width direction intersects with the length direction; The width direction of the blade at the stage farthest from the rotary drive member is obliquely intersected with the length direction of the rotating shaft; wherein, of the two included angles formed by the oblique intersection near the connecting port, the angle closer to the rotation direction of the rotating shaft is a first acute angle; The width direction of the blade closest to the rotary drive member is obliquely intersected with the length direction of the rotating shaft; wherein, of the two angles formed by the oblique intersection near the connecting port, the one that is farther back than the rotation direction of the rotating shaft is the second acute angle.

3. The vacuum gauge according to claim 2, wherein: in, The first acute angle is equal to the second acute angle.

4. The vacuum gauge according to claim 2, wherein: in, The value range of the first acute angle includes [45°, 90°); and / or the value range of the second acute angle includes [45°, 90°).

5. The vacuum gauge according to claim 2, wherein: The width direction of the intermediate-stage blades is parallel to the length direction of the rotating shaft; wherein, the intermediate-stage blades are blades between the impeller at the stage farthest from the rotating drive member and the impeller at the stage closest to the rotating drive member.

6. A method for calibrating a vacuum gauge, characterized in that: in, The vacuum gauge includes an impeller rotor, a rotary drive member, and a controller; the method is applied to the controller; The method comprises: Constructing an initial mathematical model between the power and vacuum degree of the rotary drive member; controlling the rotary drive member to rotate at a fixed speed, and collecting the power data and corresponding vacuum degree data; and The power data and the vacuum degree data are used to fit the initial mathematical model to obtain a calibrated mathematical model; wherein the calibrated mathematical model is used to determine the vacuum degree of the target cavity according to the detected power of the rotating drive member.

7. A method for measuring vacuum, characterized in that: The method is applied to a controller in a vacuum gauge; wherein the vacuum gauge comprises an impeller rotor, a rotating drive member and the controller; The method comprises: acquiring the detected power of the rotating drive member; and Calculating the vacuum degree of the target cavity according to the power using a pre-calibrated calibration mathematical model; Wherein, the calibration mathematical model is obtained by the method according to claim 6.

8. The method according to claim 7, characterized in that In the process of obtaining the calibration mathematical model, controlling the rotary drive member to rotate at a fixed speed and collecting the power data and the corresponding vacuum degree data includes: controlling the rotary drive member to rotate at a fixed speed under a fixed input voltage, and collecting input current data of the rotary drive member and the corresponding vacuum degree data; In the process of obtaining the calibration mathematical model, the power data and the vacuum degree data are used to fit the initial mathematical model to obtain the calibration mathematical model, including: fitting the initial mathematical model with the input current data and the vacuum degree data to obtain the calibration mathematical model; The method of calculating the vacuum degree of the target cavity according to the power using a pre-calibrated calibration mathematical model includes calculating the vacuum degree of the target cavity according to the detected current of the rotating drive member using the pre-calibrated calibration mathematical model.

9. The method according to claim 7, characterized in that In the process of obtaining the calibration mathematical model, an initial mathematical model between the power and vacuum degree of the rotary drive member is constructed, including: The range of the vacuum gauge is divided into a low vacuum range and a high vacuum range; wherein the low vacuum range is [10 5 Pa,10 -2 Pa], the high vacuum range is [10 -2 Pa,10 -5 Pa]; Corresponding to the low vacuum range, constructing a first initial mathematical model; and Corresponding to the high vacuum range, constructing a second initial mathematical model; The first initial mathematical model and the second initial mathematical model are respectively: P vac =k1·P w P vac =k2·P w Where, P vac Characterize the vacuum degree, P w Characterizes the power of the rotating drive component, k1 and k2 are coefficients to be fitted.

10. The method according to claim 9, characterized in that In the process of obtaining the calibration mathematical model, controlling the rotary drive member to rotate at a fixed speed and collecting the power data and the corresponding vacuum degree data includes: controlling the rotary drive member to rotate at a first fixed speed, and collecting first power data and corresponding first vacuum degree data; and controlling the rotary drive member to rotate at a second fixed speed, and collecting second power data and corresponding second vacuum degree data; The first vacuum degree data is located in a low vacuum degree range, the second vacuum degree data is located in a high vacuum degree range, and the first fixed rotational speed is less than the second fixed rotational speed.

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