Vacuum gauge based on electromagnetic induction principle

Abstract

The utility model relates to a vacuum gauge based on an electromagnetic induction principle, belongs to the technical field of vacuum measuring equipment, and solves at least one of the problems of large accumulated processing error among parts of a capacitor vacuum gauge, complex bridge circuit trimming, temperature drift of an electronic device, analog circuit distortion and the like in the prior art. The utility model provides a vacuum gauge based on an electromagnetic induction principle, which comprises a vertical support structure arranged above a strain diaphragm, and two sides of the vertical support structure are provided with parallel sheet magnets with opposite magnetic poles; insulating layers are arranged on the front faces and / or the back faces of the vertical supporting structures, and parallel metal wires are arranged on the insulating layers. According to the vacuum gauge, the strain diaphragm structure is reserved, the deformation of the strain diaphragm is measured by using a simple electromagnetic induction principle, and a complicated analog circuit is not needed; moreover, the method is high in measurement precision, is less affected by the environment, is easy to analyze and process an output signal, and can be suitable for application scenes with harsh environmental conditions.

Description

Technical Field

[0001] The utility model relates to the technical field of vacuum measuring equipment, in particular to a vacuum gauge based on the principle of electromagnetic induction. Background Art

[0002] At present, the most common types of vacuum measurement products include resistance vacuum gauges; capacitance vacuum gauges; ionization vacuum gauges; and MEMS vacuum gauges. Among these different types of vacuum measurement technologies and products, because capacitance vacuum gauges basically use elastic strain film as a pressure response component, the strain diaphragm can completely isolate the measuring device and circuit from the measured medium, playing a protective role. Therefore, capacitance vacuum gauges are widely used in many fields.

[0003] The common structure of capacitive pressure sensor is to use alloy pressure strain diaphragm as capacitor, in which one electrode forms a capacitor with the conductive coating on the ceramic substrate. When the pressure on both sides of the alloy strain diaphragm changes, a pressure difference is generated, causing the alloy strain diaphragm to deform, thereby changing the distance between the alloy strain diaphragm and the conductive layer on the ceramic substrate, and changing the capacitance value. The pressure in the measured space is measured by measuring the capacitance value.

[0004] The principle of such pressure measurement is not complicated, but the factors affecting capacitance measurement are very complicated. Because the change in capacitance is caused by the deformation of the strain diaphragm load, but the maximum deformation at the center of the diaphragm is in the micron range, and the processing error of the parts that control the electrode spacing is also in the micron range. There are also many factors that affect the pressure measurement, such as the area error and thickness error of the conductive coating prepared on the ceramic substrate; the balancing of the bridge circuit that measures the capacitance difference; the temperature drift of electronic devices; the distortion of analog circuits; the interference of capacitive devices, etc., which will cause the output signal to be delayed, oscillated, distorted, drifted, etc.

[0005] Therefore, it is necessary to develop a relatively simple vacuum measurement device that is not easily disturbed by the environment. Utility Model Content

[0006] In view of the above analysis, the utility model aims to provide a vacuum gauge based on the principle of electromagnetic induction, so as to solve at least one of the problems in the prior art of the capacitive vacuum gauge, such as large cumulative processing errors between components, complex bridge circuit balancing, temperature drift of electronic devices, and distortion of analog circuits.

[0007] For the convenience of describing the specific structure of the vacuum gauge of the utility model, as follows Figure 1 As shown, the plane where the strain diaphragm is in its initial state is the horizontal direction (left-right direction), and the vertical direction is the vertical direction (up-down direction); unless otherwise specified, the dimension of each component in the vertical direction is defined as the length, the dimension in the horizontal direction is the thickness, and the dimension perpendicular to the paper surface is the width.

[0008] The utility model discloses a vacuum gauge based on the principle of electromagnetic induction, the vacuum gauge comprises a strain diaphragm 3 and a vertical support structure 7 arranged above the strain diaphragm 3, one end of the vertical support structure 7 is connected to the strain diaphragm 3, and can move up and down with the deformation of the strain diaphragm 3;

[0009] A sheet magnet 6 is disposed on both sides of the vertical support structure 7, and the positions of the two sheet magnets 6 are fixed, arranged in parallel, and the magnetic poles are opposite;

[0010] An insulating layer 9 is provided on the front and / or back side of the vertical support structure 7 , and parallel metal wires 10 of equal length are provided on the insulating layer 9 .

[0011] Specifically, the vacuum gauge further includes a housing 5;

[0012] The strain diaphragm 3 is arranged in the lower middle part of the shell 5. The size of the strain diaphragm 3 matches the inner size of the shell 5. The edge of the diaphragm is fixed to the shell 5. The cavity surrounded by the shell 5 above the strain diaphragm 3 forms a standard pressure chamber.

[0013] Specifically, there is a gap between the upper end surface of the sheet magnet 6 and the housing 5 , and between the lower end surface of the sheet magnet 6 and the strain diaphragm 3 .

[0014] Specifically, the vacuum gauge further includes a magnet clamping device 2;

[0015] The magnet clamping device 2 includes a fixed end and a free end. The magnet clamping device 2 is connected to the housing 5 via the fixed end. The free end of the magnet clamping device 2 is provided with the sheet magnet 6 .

[0016] Specifically, there are two magnet clamping devices 2 , which are symmetrically and evenly spaced on both sides of the vertical support structure 7 .

[0017] Specifically, the sheet magnet 6 is fixed to the free end of the magnet clamping device 2 by bonding or snapping.

[0018] Preferably, an insulating layer 9 is provided on both the front and back sides of the vertical support structure 7 , and parallel metal wires 10 are prepared at the same positions on the front and back sides of the insulating layer 9 .

[0019] Furthermore, the parallel metal wires 10 prepared at the same position on the front and back sides of the insulating layer 9 are connected together into a conductive wire to form a parallel structure.

[0020] Furthermore, the distance between the uppermost metal wire and the lowermost metal wire of the parallel metal wires 10 is not less than three times the length of the sheet magnet 6; under initial conditions, the centers of the paired sheet magnets 6 and the vertical support structure 7 should be located on the same horizontal line.

[0021] Furthermore, the length of the parallel metal wires 10 is not greater than the width of the sheet magnet 6 ; and the intervals between adjacent parallel metal wires 10 are equal.

[0022] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0023] 1. The utility model retains the design of the strain diaphragm, realizes the complete isolation of the measuring device and circuit from the measured medium, and plays a protective role; on this basis, the deformation of the strain diaphragm is measured by using the principle of electromagnetic induction. The device is simple, the cumulative processing error is small (almost no cumulative processing error), and the problem of output signal temperature drift due to temperature changes in the capacitor vacuum gauge circuit is avoided.

[0024] The utility model sets a vertical support structure above the strain diaphragm so that the vertical support structure can move up and down with the movement of the strain diaphragm. Generally speaking, the tested medium is mostly positive pressure, because a long-term stable reference pressure chamber is established inside the sensor, and the interior is a high vacuum environment. When the external pressure of the diaphragm changes, the internal and external pressure difference will cause the diaphragm to produce a corresponding load deformation (upward bulge), and the vertical support structure will also move vertically upward with the bulge of the diaphragm. The utility model sets two sheet magnets of moderate size at equal distances on both sides of the vertical support structure through a magnet clamping device set on the shell, and the magnetic poles are set oppositely, so that there is a magnetic field in the vertical direction that is first strengthened, maintained unchanged in the middle section, and then weakened, the direction of the magnetic flux lines is horizontal to the left or right (determined by the placement of the magnetic poles), the constant magnetic field in the middle section is a parallel area of ​​the magnetic flux lines, and the magnetic field of the upper and lower boundary sections is a circular magnetic field that gradually weakens (the direction of the magnetic flux lines is from the N pole to the S pole). Since an insulating layer is provided on the vertical support structure, and parallel metal wires are provided on the insulating layer, when the parallel metal wires move in the magnetic field, induced electromotive force / induced current will be generated. According to the electromagnetic induction formula:

[0025] I=BLV / R

[0026] Among them, I represents the induced current, B represents the magnetic field strength, L represents the length of the parallel metal wires, V represents the speed (in the utility model, it represents the speed of vertical movement), and R represents the resistance of the parallel metal wires. Since the sheet magnet will not move with the deformation of the strain diaphragm, the distribution of the magnetic field is unchanged. The length and resistance of the parallel metal wires are the same, and since the vertical support structure is an integral whole, the instantaneous speed of each parallel metal wire is also the same. Therefore, the absolute value of the induced current is related to B, L, V, and R, but the relative value is only related to the magnetic field strength.

[0027] For example, the parallel metal wires are numbered 1, 2, 3, and so on from top to bottom (n is a positive integer greater than 1). At a certain moment, the ratio of the induced current intensity of metal wire No. 1 to that of metal wire No. n is I1:I n =B1:B n , that is to say, the relative magnitude of the induced current of two parallel metal wires at a certain moment depends only on the magnetic field strength at the location of the two metal wires at that moment. In other words, the vertical support structure is equivalent to a ruler, and the parallel metal wires are equivalent to the scale on the ruler. The role of this ruler is to determine the magnetic field strength at the location according to the magnitude of the induced current, and then determine how much displacement the ruler has produced in the vertical direction.

[0028] In order to more clearly illustrate the measurement principle of the utility model, the following will be combined with the mechanism diagram ( Figure 3 ) is described in detail. When the diaphragm is deformed, the vertical support structure moves up and down, and the parallel metal wires will cut the magnetic flux lines. Because the central area of ​​the magnetic field is a parallel magnetic field, but there is a gradually weakening circular magnetic field around the magnet, the induced current generated by the metal wire cutting the magnetic field will be relatively weakened in the circular magnetic field area, and the parallel magnetic field area is the strongest. The intensity of the induced current generated by the metal wire entering the magnetic field range will change due to the magnetic strength, and a trapezoidal wave will be generated. Taking into account the accuracy of the measurement, and the different cutting speeds and current intensities each time, the measurement point selects the metal wire current intensity at 50% of the peak value as the displacement judgment standard.

[0029] Specific instructions, such as Figure 3 As shown in the figure, when the diaphragm just begins to deform, due to the large pressure difference and the fast deformation speed, the vertical support structure moves upward quickly. At this time, it can be approximately considered that when the induced current is generated, the strain diaphragm is still in the initial state and has not yet begun to deform (that is, it is just about to begin to deform). This time can be recorded as T0. At this time, the metal wire numbered 5 is just in the magnetic field strength of 1 / 2B max position (i.e. the induced current signal strength derived from the metal wire numbered 5 is exactly 50% of the peak current strength). Strictly speaking, at the initial moment of measurement, the diaphragm is about to begin to deform, and at this moment the diaphragm has a large acceleration, and the speed starts to accelerate from 0. However, since the measuring medium is generally gas, the diaphragm deformation is related to the free movement mode and free path of gas molecules. The acceleration at this moment is extremely large, and the acceleration time of the diaphragm deformation is extremely short and can be almost ignored. Therefore, it can be considered that at the moment of measurement, the vertical support structure immediately obtains a large speed.

[0030] As the deformation of the diaphragm increases, the deformation speed gradually decreases, so the induced current intensity gradually decreases. When the deformation of the diaphragm reaches the maximum, the metal wire numbered 10 is exactly at the position where the magnetic field intensity is 1 / 2B. maxFrom the above mechanism, we can see that the magnetic field does not move with the deformation of the diaphragm, so the displacement distance X of the vertical support structure (i.e. the degree of deformation of the diaphragm) is X = (1 / 2B at the end of deformation) max The metal wire number corresponding to the position - 1 / 2B when deformation begins max The metal line number corresponding to the position of )△x, where △x is the distance between adjacent parallel metal lines; in this example, X=(10-5)△x.

[0031] In the specific implementation process, the upper and lower 1 / 2 peak points can be selected for averaging (when the annular magnetic field gradually weakens, there are two B = 1 / 2B max point), thereby improving the measurement accuracy. Figure 3 For example, at the beginning of the measurement, another 1 / 2B max The position is roughly between the 21st and 22nd metal wires, and another 1 / 2B max The position is roughly between metal wires 26 and 27. This also shows that in the actual measurement process, the 1 / 2 peak point of the induced current (also the 1 / 2B peak point of the magnetic field strength) max The point) does not necessarily correspond to a specific number, but it should be read more accurately based on the induced current intensity diagram, that is, the calculation process may be x=(9.9-5.3)△x.

[0032] Therefore, the utility model introduces the concept of virtual numbering. First, a graph is drawn by measuring the induced current intensity data of the actual metal wire, and each isolated point value is connected to form a curve of the induced current intensity with respect to the metal wire number. Then, the virtual number corresponding to the 1 / 2 peak point of the induced current is found. Figure 3 For example, a straight line parallel to the horizontal axis is drawn with the 1 / 2 peak value of the induced current. The horizontal coordinate of the intersection of this straight line and the induced current intensity curve is the point at which the line is located at 1 / 2B at this moment. max The virtual number of the metal wire at the position, so the virtual number can be a decimal (as can be seen from the above, the actual metal wire number can only be a positive integer).

[0033] It is worth emphasizing that although the 1 / 2 peak point of the induced current is read from the induced current intensity diagram, reducing the distance between adjacent parallel metal wires as much as possible and increasing the number of parallel metal wires can make the induced current intensity diagram more accurate and obtain more accurate measurement results.

[0034] From the above description, it can be seen that the technical solution provided by the utility model avoids the problem that the analog circuit used by the capacitive vacuum gauge is too complicated and the bridge circuit is difficult to balance; and overcomes the problem of temperature drift of the output signal due to temperature change of the circuit, and realizes the measurement of diaphragm deformation based on electromagnetic induction current, so that the above vacuum gauge can be suitable for application scenarios with more complex and demanding environments.

[0035] 2. The vacuum gauge described in the utility model has a simple output signal, which is a basic current signal and is easy to analyze. It can realize real-time drawing and real-time measurement without complex analytical circuits. It can detect the deformation of the diaphragm at each specific moment and obtain the pressure data of the medium.

[0036] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the following content, and some advantages can be obvious from the description or understood by implementing the present invention. The purpose and other advantages of the present invention can be achieved and obtained through the contents specifically pointed out in the text and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings are only used for the purpose of illustrating specific embodiments and are not to be considered as limiting the present invention. In the entire drawings, the same reference symbols represent the same components.

[0038] Figure 1 This is the overall schematic diagram of the vacuum gauge based on the principle of electromagnetic induction;

[0039] Figure 2 It is a partial enlarged diagram of the overall schematic diagram of the vacuum gauge based on the electromagnetic induction principle;

[0040] Figure 3 Schematic diagram of the measurement mechanism of a vacuum gauge based on the principle of electromagnetic induction.

[0041] Reference numerals:

[0042] 1- degassing device; 2- magnet clamping device; 3- strain diaphragm; 4- detection port; 5- housing; 6- sheet magnet; 7- vertical support structure; 8- electrical signal lead-out port; 9- insulation layer; 10- parallel metal wires. DETAILED DESCRIPTION

[0043] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0044] The utility model provides a vacuum gauge based on the principle of electromagnetic induction, the vacuum gauge comprises a vertical support structure arranged above a strain diaphragm, the vertical support structure is connected to the strain diaphragm, and can move up and down with the deformation of the strain diaphragm;

[0045] Fixed parallel sheet magnets with opposite magnetic poles are arranged on both sides of the vertical support structure;

[0046] An insulating layer is provided on the front and / or back of the vertical support structure, and parallel metal wires of equal length are provided on the insulating layer. Strictly speaking, the widths of the metal wires should also be the same, but since the metal wires are generally prepared uniformly in actual implementation, except for extremely special cases, the widths of the prepared metal wires can be considered to be the same within the error range, and only the length needs to be limited.

[0047] The utility model arranges a vertical support structure above the strain diaphragm, and the vertical support structure is connected to the strain diaphragm, so that the vertical support structure can move up and down with the deformation of the strain diaphragm. Generally speaking, the tested medium is mostly positive pressure, the diaphragm will bulge upward under the action of the pressure difference, and the vertical support structure will also move vertically upward with the bulge of the diaphragm.

[0048] In a possible implementation manner of the utility model, two fixed sheet magnets of appropriate size are arranged at equal distances on both sides of the vertical support structure through a magnet clamping device arranged on the outer shell, and the magnetic poles are arranged relative to each other, so that in the vertical direction, there is a magnetic field that is first strengthened, maintained unchanged in the middle section, and then weakened, and the direction of the magnetic flux lines is horizontally to the left or right (determined by the placement of the magnetic poles), the constant strength magnetic field in the middle section is the area parallel to the magnetic flux lines, and the magnetic field in the upper and lower boundary sections is a circular magnetic field that gradually weakens (the direction of the magnetic flux lines starts from the N pole and reaches the S pole).

[0049] Since an insulating layer is provided on the vertical support structure, and parallel metal wires are provided on the insulating layer, when the parallel metal wires move in the magnetic field, induced electromotive force / induced current will be generated. According to the electromagnetic induction formula:

[0050] I=BLV / R

[0051] Among them, I represents the induced current, B represents the magnetic field strength, L represents the length of the parallel metal wires, V represents the speed (in the utility model, it represents the speed of vertical movement), and R represents the resistance of the parallel metal wires. Since the sheet magnet will not move with the deformation of the strain diaphragm, the distribution of the magnetic field is unchanged. The length and resistance of any two parallel metal wires are the same, and since the vertical support structure is an integral whole, the instantaneous speed of each parallel metal wire is also the same. Therefore, although the absolute value of the induced current generated by any two metal wires is related to B, L, V, and R, the relative size of the induced current is only related to the magnetic field strength at the location of the metal wires.

[0052] For example, the parallel metal wires are numbered 1, 2, 3, and so on from top to bottom (n is a positive integer greater than 1). At a certain moment, the ratio of the induced current intensity of metal wire No. 1 to that of metal wire No. n is I1:I n =B1:B n , that is to say, the relative magnitude of the induced current of two parallel metal wires at a certain moment depends only on the magnetic field strength at the location of the two metal wires at that moment. In other words, the vertical support structure is equivalent to a ruler, and the parallel metal wires are equivalent to the scale on the ruler. The role of this ruler is to determine the magnetic field strength at the location according to the magnitude of the induced current, and then determine how much displacement the ruler has produced in the vertical direction.

[0053] In order to more clearly illustrate the measurement principle of the utility model, the following will be combined with the mechanism diagram ( Figure 3 ) is described in detail. When the diaphragm is deformed, the vertical support structure moves up and down, and the parallel metal wires will cut the magnetic flux lines. Because the central area of ​​the magnetic field is a parallel magnetic field, but there is a gradually weakening circular magnetic field around the magnet, the induced current generated by the metal wire cutting the magnetic field will be relatively weakened in the circular magnetic field area, and the parallel magnetic field area is the strongest. The intensity of the induced current generated by the metal wire entering the magnetic field range will change due to the magnetic strength, and a trapezoidal wave will be generated. Taking into account the accuracy of the measurement, and the different cutting speeds and current intensities each time, the measurement point selects the metal wire current intensity at 50% of the peak value as the displacement judgment standard.

[0054] Specific instructions, such as Figure 3 As shown in the figure, when the diaphragm just begins to deform, due to the large pressure difference and the fast deformation speed, the vertical support structure moves upward quickly. At this time, it can be approximately considered that when the induced current is generated, the strain diaphragm is still in the initial state and has not yet begun to deform (that is, it is just about to begin to deform). This time can be recorded as T0. At this time, the metal wire numbered 5 is just in the magnetic field strength of 1 / 2B max position (i.e. the induced current signal strength derived from the metal wire numbered 5 is exactly 50% of the peak current strength). Strictly speaking, at the initial moment of measurement, the diaphragm is about to begin to deform, and at this moment the diaphragm has a large acceleration, and the speed starts to accelerate from 0. However, since the measuring medium is generally gas, the diaphragm deformation is related to the free movement mode and free path of gas molecules. The acceleration at this moment is extremely large, and the acceleration time of the diaphragm deformation is extremely short and can be almost ignored. Therefore, it can be considered that at the moment of measurement, the vertical support structure immediately obtains a large speed.

[0055] As the deformation of the diaphragm increases, the deformation speed gradually decreases, so the induced current intensity gradually decreases. When the deformation of the diaphragm reaches the maximum, the time is T end, the metal wire numbered 10 is exactly located at a magnetic field strength of 1 / 2B max Strictly speaking, at this moment the diaphragm is about to stop deforming and the speed is about to become 0, so the induced current intensity will be small and the induced current will disappear in the next moment. However, in order to more clearly demonstrate the measurement mechanism of the utility model, Figure 3 (Schematic diagram) end The induced current intensity corresponding to the moment is amplified for observation and display.

[0056] From the above mechanism description, it can be seen that the magnetic field does not move with the deformation of the diaphragm, so the displacement distance X of the vertical support structure (i.e. the degree of deformation of the diaphragm) is:

[0057] X=(1 / 2B at the end of deformation max The metal wire number corresponding to the position - 1 / 2B when deformation begins max The metal wire number corresponding to the position)△x

[0058] Where △x is the distance between adjacent parallel metal wires;

[0059] In this example, X=(10-5)Δx.

[0060] In the specific implementation process, the upper and lower 1 / 2 peak points can be selected for averaging (when the annular magnetic field gradually weakens, there are two B=1 / 2B in the vertical direction). max point), thereby improving the measurement accuracy. Figure 3 For example, at the beginning of the measurement, another 1 / 2B max The position is roughly between the 21st and 22nd metal wires, and another 1 / 2B max The position is roughly between metal wires 26 and 27. This also shows that in the actual measurement process, the 1 / 2 peak point of the induced current (also the 1 / 2B peak point of the magnetic field strength) max The point) does not necessarily correspond to a specific number, but it should be read more accurately based on the induced current intensity diagram, that is, the calculation process may be X=(9.9-5.3)△x.

[0061] Therefore, the present invention introduces the concept of virtual numbering. First, a graph is drawn by measuring the induced current intensity data of the actual metal wire, and each isolated point value is connected to form a curve of the induced current intensity with respect to the metal wire number. Then, the virtual number corresponding to the 1 / 2 peak point of the induced current is found. Figure 3 For example, take the 1 / 2 peak value of the induced current at a certain moment as an example, and draw a straight line parallel to the horizontal axis. The horizontal coordinate of the intersection of this straight line and the induced current intensity curve at this moment is the value at 1 / 2B at this moment. maxThe virtual number of the metal wire at the position, so the virtual number can be a decimal (as can be seen from the above, the actual metal wire number can only be a positive integer).

[0062] It is worth emphasizing that although the 1 / 2 peak point of the induced current is read from the induced current intensity diagram, reducing the distance between adjacent parallel metal wires as much as possible and increasing the number of parallel metal wires can make the induced current intensity curve smoother and obtain more accurate measurement results.

[0063] Specifically, the vacuum gauge includes a housing, a strain diaphragm, and a magnet clamping device;

[0064] The strain diaphragm is arranged in the middle and lower part of the shell. The size of the strain diaphragm matches the size of the shell. The edge of the diaphragm is fixed to the shell. It can be fixed by bonding, embedding, pressing, etc., but attention should be paid to the air tightness of the connection.

[0065] A vertical support structure is provided above the strain diaphragm, and there is a distance between the vertical support structure and the top of the housing to leave space for deformation of the diaphragm;

[0066] The strain diaphragm isolates the measuring device from the medium to be measured, protects the measuring device, and avoids contamination of the medium to be measured. In addition, the strain diaphragm and the upper part of the shell form a standard pressure chamber, and the pressure of the chamber can be adjusted as needed to set it to a high vacuum state or a certain negative pressure;

[0067] The magnet clamping device includes a fixed end and a free end. The magnet clamping device is connected to the shell through the fixed end. There are two magnet clamping devices, which are symmetrically and evenly spaced on both sides of the vertical support structure. The free ends of the magnet clamping devices are respectively provided with sheet magnets, and the magnetic poles of the sheet magnets on the two magnet clamping devices are arranged opposite to each other; the sheet magnets can be fixed to the free ends of the magnet clamping devices by bonding or snapping.

[0068] The magnet clamping device is fixedly connected to the housing to ensure that the magnet will not move due to the deformation of the diaphragm during the measurement process (that is, the magnetic field will not move); the sheet magnets are arranged in parallel to each other to obtain a magnetic field that is parallel in the middle and weakened in an annular manner on the upper and lower sides.

[0069] There are gaps between the upper end surface of the sheet magnet and the shell, and between the lower end surface of the sheet magnet and the strain diaphragm. In fact, the length of the sheet magnet is much smaller than the length of the vertical support structure, so gaps will naturally appear between the upper and lower edges of the sheet magnet and the shell and the strain diaphragm.

[0070] The top of the housing is provided with an electrical signal lead-out hole, and the conductive wires led out from both ends of the parallel metal wires are integrated and uniformly led out through the electrical signal lead-out hole;

[0071] Furthermore, the electrical signal lead-out hole should be protected and tested for air tightness to avoid leakage and other phenomena that may cause the pressure inside the standard pressure chamber to be uncontrollable;

[0072] The bottom of the housing is provided with a detection port for introducing a test medium for pressure detection.

[0073] Specifically, an insulating layer is provided on both the front and back sides of the vertical support structure, and parallel metal wires are prepared at the same positions on the front and back sides of the insulating layer.

[0074] Preferably, parallel metal wires are prepared at the same positions on the front and back sides of the insulating layer and connected together to a conductive wire to form a parallel structure.

[0075] By preparing parallel metal wires at the same position on the front and back sides of the insulating layer and forming a parallel structure, the collected current signal can be doubled, the impact of noise and measurement errors can be reduced, and the measurement accuracy can be improved.

[0076] Specifically, the distance between the uppermost metal wire and the lowermost metal wire of the parallel metal wires is not less than three times the length of the sheet magnet;

[0077] The above setting is to ensure that the coverage of the parallel metal wires is as large as possible from the distribution range of the magnetic field, such as Figure 3 As shown, if the coverage of the parallel metal wires is too small, it may be impossible to detect the point where the induced current is 0, and in extreme cases, even the metal wire corresponding to the 50% peak value cannot be detected. Therefore, in order to ensure the accuracy of the measurement and the integrity of the induced current intensity image, the distance between the uppermost metal wire and the lowermost metal wire of the parallel metal wires is not less than three times the length of the sheet magnet.

[0078] Preferably, under the initial condition, the centers of the paired sheet magnets and the vertical support structure should be located on the same horizontal line. The above arrangement also helps to make the coverage of the parallel metal lines as large as possible as the distribution range of the magnetic field. Another advantage is that the diaphragm can be detected regardless of whether it is deformed downward or upward, but in actual implementation, the diaphragm hardly deforms downward.

[0079] Preferably, the length of the parallel metal wires is not greater than the width of the sheet magnet; the spacing between adjacent parallel metal wires is equal. According to common knowledge, the magnetic field exists in three dimensions in space, so there will also be a gradually decaying magnetic field in the direction perpendicular to the paper. If the length of the parallel metal wires is too long, it will cause the cutting of the surrounding magnetic field. However, since the external magnetic field is not uniform, it may affect the measurement accuracy. Therefore, the parallel metal wires should be ensured to cut the central area of ​​the magnetic field as much as possible, but the length of the metal wires cannot be too short, otherwise the induced electromotive force / induced current will be too small. The spacing between adjacent parallel metal wires is equal to facilitate the calculation of the diaphragm deformation during subsequent image processing.

[0080] Preferably, the parallel metal lines are prepared by metal semiconductor etching process, and the line width is controlled below 100nm. Too large line width will lead to reduced measurement accuracy, but the line width cannot be reduced indefinitely, which will increase the risk of rupture and short circuit on the one hand, and on the other hand, it will lead to excessive resistance and reduced induced current intensity.

[0081] Preferably, the width of the vertical support structure is 8 to 12 mm. The width and length of the vertical support structure should not be too large or too small. If the size is too large, the weight will increase and affect the deformation of the diaphragm; if the size is too small, the coverage of the parallel metal wires may be too small, resulting in inaccurate measurement and other consequences.

[0082] Specifically, the top of the housing is also provided with a degassing device, in which a degassing material is arranged. The degassing device is particularly effective when the standard pressure chamber is set to a high vacuum state, and a getter is arranged in the degassing device to ensure that the interior of the standard pressure chamber is maintained in a high vacuum state.

[0083] The utility model also discloses an application of a vacuum gauge based on the electromagnetic induction principle, and uses the vacuum gauge to perform pressure measurement.

[0084] Exemplarily, pressure measurement can be performed according to the following steps:

[0085] S1: Set the standard pressure chamber of the vacuum gauge to the preset pressure and perform air tightness test;

[0086] S2: Connect the conductive wire leading out from the electrical signal outlet to the analysis device or computer;

[0087] S3: Pass the test medium into the detection port, start the detection, and record the time and the instantaneous induced current intensity of each metal wire in real time through an analysis device or a computer;

[0088] S4: Draw the induced current intensity diagram, read the virtual number of the metal wire corresponding to the 50% current peak value, and calculate the diaphragm deformation at a specific moment, and then obtain the pressure of the medium to be measured.

[0089] It is worth emphasizing that, in a specific implementation, it is necessary to calibrate the diaphragm deformation in advance with a known pressure value, and perform pressure measurement according to the above steps based on the calibration result.

[0090] Exemplarily, the calibration process can be performed according to the following process:

[0091] Taking the calibration of the diaphragm deformation under high vacuum conditions of a specific vacuum gauge as an example, the standard pressure chamber pressure of the above vacuum gauge is adjusted to high vacuum and an airtightness test is performed. The medium with pressures of 0.02Torr, 0.05Torr, 0.1Torr, 0.2Torr, 0.5Torr, and 1Torr (the calibration range and more point values ​​can be selected according to actual needs / corresponding range) is respectively passed through the detection port for calibration, and the diaphragm deformation data under the corresponding pressure is measured. In general, the measurement of the vacuum gauge is based on a negative pressure environment, so it is called vacuum, and the measurement range of most models is based on a range of ≤0.1MPa under a standard atmospheric pressure. Although the vacuum gauge provided by the utility model uses the principle of electromagnetic induction to characterize the diaphragm load deformation, the degree of deformation of the diaphragm under medium pressure and the approximate range can refer to the capacitive thin film vacuum gauge.

[0092] Taking the common capacitive film vacuum gauge in this field as an example, among the common models of capacitive film vacuum gauge, the smallest range is 0.02Torr, and the most common range starts from 0.1Torr. The measurement range of the capacitive film vacuum gauge is 4 orders of magnitude below the calibrated range value. Taking the capacitive film vacuum gauge with a range of 1Torr as an example, the values ​​above 1E-4Pa can only be used as a reference, and the values ​​above 1E-3Pa are valid values.

[0093] The above diaphragm deformation data and corresponding pressure are plotted into a measurement standard curve under high vacuum conditions, and the standard curve can be queried later to obtain the pressure of the unknown pressure medium to be measured. That is, the diaphragm deformation corresponding to a certain unknown pressure medium to be measured is measured using the vacuum gauge, and then the corresponding pressure value is obtained by looking up the table / curve.

[0094] It should be noted that for thin-film vacuum gauges, the deformation at the center of the diaphragm is linearly related to the load deformation to a certain extent. This linear range is very small and only approximately linear, so nonlinear compensation is required. In the actual debugging process, the corresponding metal wire number can be measured in advance through different pressure values ​​to obtain the relationship between pressure and metal wire number, and then the compensation characteristics can be obtained by comparing the linear relationship, so as to perform nonlinear compensation in the later signal processing.

[0095] In the specific implementation process, the above standard curve can also be entered into the analysis device or computer in advance, so that the analysis device or computer directly outputs the deformation data and the corresponding "pressure value" at each moment. It is worth noting that, except for T end The pressure value data corresponding to the moment can represent the pressure value of the medium to be measured, and the "pressure value" output during the process has no practical meaning.

[0096] The above is only a preferred specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed in the present invention should be covered by the protection scope of the present invention.

Claims

1. A vacuum gauge based on the principle of electromagnetic induction, characterized in that: The vacuum gauge comprises a strain diaphragm (3) and a vertical support structure (7) arranged above the strain diaphragm (3), one end of the vertical support structure (7) is connected to the strain diaphragm (3) and can move up and down with the deformation of the strain diaphragm (3); A sheet-shaped magnet (6) is respectively arranged on both sides of the vertical support structure (7), and the positions of the two sheet-shaped magnets (6) are fixed, arranged in parallel, and the magnetic poles are opposite to each other; An insulating layer (9) is provided on the front and / or back of the vertical support structure (7), and parallel metal wires (10) of equal length are arranged on the insulating layer (9).

2. The vacuum gauge according to claim 1, characterized in that: The vacuum gauge further comprises a housing (5); The strain diaphragm (3) is arranged in the lower middle part of the outer shell (5); the size of the strain diaphragm (3) matches the inner size of the outer shell (5); the edge of the diaphragm is fixed to the outer shell (5); the cavity surrounded by the outer shell (5) above the strain diaphragm (3) forms a standard pressure chamber.

3. The vacuum gauge according to claim 2, characterized in that: There is a gap between the upper end surface of the sheet-shaped magnet (6) and the housing (5), and between the lower end surface of the sheet-shaped magnet (6) and the strain diaphragm (3).

4. The vacuum gauge according to claim 1, characterized in that: The vacuum gauge further comprises a magnet clamping device (2); The magnet clamping device (2) comprises a fixed end and a free end. The magnet clamping device (2) is connected to the housing (5) via the fixed end. The free end of the magnet clamping device (2) is provided with the sheet magnet (6).

5. The vacuum gauge according to claim 4, characterized in that: There are two magnet clamping devices (2), which are symmetrically and evenly spaced on both sides of the vertical support structure (7).

6. The vacuum gauge according to claim 4, characterized in that: The sheet magnet (6) is fixed to the free end of the magnet clamping device (2) by bonding or snapping.

7. The vacuum gauge according to any one of claims 1 to 6, characterized in that: The vertical support structure (7) is provided with an insulating layer (9) on both the front and back sides, and parallel metal wires (10) are prepared at the same positions on the front and back sides of the insulating layer (9).

8. The vacuum gauge according to claim 7, characterized in that: The parallel metal wires (10) prepared at the same positions on the front and back sides of the insulating layer (9) are connected together into a conductive wire to form a parallel structure.

9. The vacuum gauge according to claim 7, characterized in that: The distance between the uppermost metal wire and the lowermost metal wire of the parallel metal wires (10) is not less than three times the length of the sheet magnet (6); under initial conditions, the centers of the paired sheet magnets (6) and the vertical support structure (7) should be located on the same horizontal line.

10. The vacuum gauge according to claim 7, characterized in that: The length of the parallel metal wires (10) is not greater than the width of the sheet magnet (6); and the spacing between adjacent parallel metal wires (10) is equal.

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