A multi-point variable-spacing three-dimensional differential sampling probe for the gas concentration field gradient vector

Abstract

The present invention relates to a multi-point variable-spacing three-dimensional differential sampling probe for a gas concentration field gradient vector, characterized in that it includes N sampling points, where N≥4. One acquisition point S0 is fixedly arranged at the first height, and the remaining N-1 acquisition points are all located at the second height. The N-1 acquisition points at the second height can synchronously approach or move away from the acquisition point S0 at the first height, so that the interior angles of the polygon formed by the N-1 acquisition points at the second height remain unchanged, but the area of the polygon will increase or decrease in multiples to adapt to application scenarios with different concentration gradient ranges. By fixing one sampling point and synchronously controlling the position changes of the other three or more sampling points through a stepping motor and a connecting skeleton structure, the present invention realizes that the structural form and layout of the sampling probe remain unchanged, and only the spacing of the sampling points is changed to adapt to application scenarios with different concentration gradient ranges.

Description

Technical Field

[0001] The present invention relates to a gas concentration detection device, in particular to a multi-point sampling probe applied to measure the gradient vector of a gas concentration field. The device simultaneously samples four spatial positions in the concentration field and then analyzes the concentration gradient vector through difference analysis. The distances between the four points are equidistant. To ensure the detection accuracy of different concentration gradients, the distances between the four points can be adaptively adjusted. Background Art

[0002] For the distribution of the gas concentration field gradient, it is necessary to perform gas sampling at four different spatial positions. After analyzing the concentrations of each component at different positions, taking one point as a reference, based on the difference principle, the concentration gradient differences in three directions are analyzed. Then, the concentration differences of each component in different directions are divided by the distance between the sampling points to obtain the concentration gradient vectors in the corresponding directions. Finally, the gradient vectors in the three directions are summed to obtain the concentration gradient vector of the reference point, which contains directional information. To effectively detect and analyze the concentration gradient vector at a specific position in three-dimensional space, at least four points of sampling are required, and the positions of the four points cannot be in the same plane. The optimal distribution of the four points is that the distances between two points are equal to each other, which can ensure the reliability of the three-dimensional space sampling process. In this way, the four sampling positions are the virtual space of a regular tetrahedron, which is also convenient for calculating the concentration gradient in the space.

[0003] However, due to the uneven distribution of gas concentration in three-dimensional space, there are both positions with large gradients and small gradients. For example, Figure 1 in the concentration field with a point-like emission source as shown, according to Fick's law of gas diffusion and the law of mass conservation, at positions closer to the emission source, the concentration gradient is larger; on the contrary, at positions farther away from the emission source, the concentration gradient is smaller. If the fixed spacing value of the four-point three-dimensional gas sampling probe is Ds, then for positions with a small gradient, the concentration difference between two points is very small, and it is difficult to ensure the detection accuracy, as shown in Figure 1 ; while for positions with a very high concentration, such as near the emission source, too large a spacing will also lead to a large deviation in the determination of its position.

[0004] Therefore, a four-point three-dimensional gas sampling probe that can adapt to a wide range of distributions of concentration gradient vectors is needed. Its purpose is to adaptively adjust the distance between any two points of the sampling probe regardless of the distance from the emission source. For example, Figure 1 in the place with a lower concentration gradient, the sampling spacing is expanded from Ds to Dl to ensure the effective detection accuracy of the concentration gradient vector in a wide range.

[0005] Although the existing gas sampling probes and their combinations have various forms, their functions do not focus on detecting and analyzing the gradient vector of the gas concentration field. The detection objects are the concentrations of different gas components at specific sampling positions. Their main technical defects are:

[0006] 1. In principle, a single-point gas sampling probe cannot achieve the distribution of the concentration field gradient at all.

[0007] According to the physical laws of gas diffusion and transmission, only by using the concentration difference between two points in space can the concentration difference in the direction between these two points be calculated and analyzed. Dividing it by the distance between them gives the concentration gradient in that direction. Therefore, if a single-point sampling probe is used, it is simply impossible to detect and analyze the gas concentration gradient vector in terms of mechanism.

[0008] 2. The spacing of the multi-point gas sampling probe is fixed, and its working mechanism cannot adapt to wide-range changes in the concentration gradient.

[0009] For the unknown concentration field in reality, there are often large differences in the concentration distribution, and similarly, there are wide-range changes in its gradient field. However, since the gas sampling probe is used for rapid analysis of the gradient vector, the gradient calculation principle depends not only on the concentration difference between the sampling points but also on the distance between the sampling points. Thus, the detection and analysis accuracy of the concentration field gradient also depend on the spacing of the sampling points. If a multi-point gas sampling probe with a fixed spacing is used, in the space with a low concentration gradient, the concentration difference between the two sampling points is even lower than the accuracy of the gas analysis equipment. At this time, the solved concentration gradient is meaningless. Therefore, it is necessary to increase the sampling point spacing to ensure the detection accuracy, as Figure 1 shown.

[0010] In summary, there is currently no four-point three-dimensional gas sampling probe applicable to the wide-range concentration field gradient vector, let alone a multi-point sampling probe that can adaptively change the distance. Summary of the Invention

[0011] The present invention designs a multi-point variable-spacing three-dimensional differential sampling probe for the gas concentration field gradient vector. The technical problem it solves is that there is currently no four-point three-dimensional gas sampling probe applicable to the wide-range concentration field gradient vector in the prior art, let alone a multi-point sampling probe that can adaptively change the distance.

[0012] To solve the above-mentioned existing technical problems, the present invention adopts the following scheme:

[0013] A multi-point variable-spacing three-dimensional differential sampling probe for the gas concentration field gradient vector, characterized in that: it includes N sampling points, N≥4, where one acquisition point S0 is fixedly arranged at the first height, and the remaining N - 1 acquisition points are all located at the second height. The N - 1 acquisition points at the second height can synchronously approach or move away from the acquisition point S0 at the first height, so that the interior angles of the polygon formed by the N - 1 acquisition points at the second height remain unchanged, but the area of the polygon will increase or decrease exponentially to adapt to application scenarios with different concentration gradient ranges.

[0014] Preferably, the N - 1 sampling points at the second height form a regular polygon, and the line S0P1 formed by the center P1 of the regular polygon and the sampling point S0 is perpendicular to the regular polygon.

[0015] Preferably, when N = 4, S1, S2, and S3 at the second height form an equilateral triangle, and S0, S1, S2, and S3 form a regular pyramid.

[0016] Preferably, the sampling point S0 is located at the end of the main sampling pipe (10), and the sampling points S1, S2, and S3 are respectively located at the ends of three decentralized sampling pipes (11). The main sampling pipe (10) penetrates and fixes the main sleeve (2). An intermediate moving slider (42) is provided on the fixed main sleeve (2). The intermediate moving slider (42) can axially move along the fixed main sleeve (2) under the action of a first transmission device. The sampling points S1, S2, and S3 are synchronously moved under the action of three second transmission devices by the intermediate moving slider (42).

[0017] Preferably, each of the second transmission devices includes a support rod (51) and a rotating decentralized sleeve (31). One end of the support rod (51) is hinged to the intermediate moving slider (42) through a second rotating shaft piece (621), and the other end of the support rod (51) is hinged to the rotating decentralized sleeve (31) through a third rotating shaft piece (631). The decentralized sampling pipe (11) passes through the rotating decentralized sleeve (31). One end of the rotating decentralized sleeve (31) is hinged to the bottom fixed slider (41) through a first rotating shaft piece (611). The lower end of the fixed main sleeve (2) is fixed on the bottom fixed slider (41). The support rod (51), the rotating decentralized sleeve (31), and the fixed main sleeve (2) form a triangle.

[0018] Preferably, the rotating decentralized sleeve (31) is tightly connected to the sleeve clamp (71), and the other end of the support rod (51) is connected to the sleeve clamp (71) through a third rotating shaft piece (631).

[0019] Preferably, the first transmission device includes a stepper motor (81) and a screw shaft (82). A top fixed slider (43) is fixed at the upper end of the fixed main sleeve (2). One end of the screw shaft (82) is connected to the top fixed slider (43) through a bearing, and the other end of the screw shaft (82) is connected to the stepper motor (81). The stepper motor (81) is installed on the bottom fixed slider (41). The protruding fixed block of the intermediate moving slider (42) has a threaded hole (423). The screw shaft (82) passes through the threaded hole (423) and can make the intermediate moving slider (42) axially move along the screw shaft (82) when rotating.

[0020] Preferably, three pairs of circumferentially evenly distributed limiting ears (422) are included outside the intermediate moving slider (42), and the three pairs of limiting ears (422) are respectively matched with a rotating shaft piece.

[0021] Preferably, the bottom fixed slider (41) has the same structure as the intermediate moving slider (42), and two protruding limiting key blocks (421) are provided inside both of them, which are matched with the limiting grooves (21) of the fixed main sleeve (2).

[0022] Preferably, a header base (9) is further included. The header base (9) is located at the root of the probe, and is used to fix the main sleeve (2) and the bottom fixed slider (41), and collect and fix the main sampling pipeline (10) and a plurality of dispersed sampling pipelines (11).

[0023] Compared with the prior art, the multi-point variable-spacing three-dimensional differential sampling probe for the gas concentration field gradient vector has the following beneficial effects:

[0024] In the present invention, by fixing one sampling point and synchronously controlling the position changes of other three or more sampling points through the stepping motor and the connecting skeleton structure, the structural form and layout of the sampling probe are kept unchanged, and only the spacing between the sampling points is changed, so as to adapt to application scenarios with different concentration gradient ranges. Description of the Drawings

[0025] Figure 1 : Schematic diagram of the gas concentration field with a source of emission and gas sampling in the prior art;

[0026] Figure 2 : Schematic diagram of the principle of variable distance between the main sampling point and the dispersed sampling points in the present invention;

[0027] Figure 3 : Structural diagram of the four-point variable-spacing three-dimensional differential sampling probe in the present invention;

[0028] Figure 4 : Schematic cross-sectional view of the fixed main sleeve in the present invention;

[0029] Figure 5 : Schematic diagram of the bottom fixed slider and the intermediate moving slider in the present invention;

[0030] Figure 6 : Schematic diagram of the top fixed slider in the present invention;

[0031] Figure 7 : Schematic diagram of the rotating shaft piece in the present invention;

[0032] Figure 8 : Schematic diagram of the header base in the present invention.

[0033] Description of the Reference Numerals:

[0034] 10—Main sampling pipeline; 11—Dispersed sampling pipeline; 2—Fixed main sleeve; 21—Limit groove; 31—Rotating dispersed sleeve; 41—Bottom fixed slider; 411—Limit key block; 412—Mounting hole; 42—Middle moving slider; 421—Limit key block; 422—Limit ear; 423—Threaded hole; 43—Top fixed slider; 51—Support rod; 611—First rotating shaft piece; 621—Second rotating shaft piece; 631—Third rotating shaft piece; 71—Sleeve clamp; 81—Stepper motor; 82—Spiral shaft; 9—Manifold base. Detailed implementation mode

[0035] The following combines Figures 2 to 8 to further illustrate the present invention:

[0036] The purpose of the present invention is to realize the high-precision detection and analysis of the gradient vector of the wide-range concentration field by adaptively synchronously adjusting the spacing of the four-point three-dimensional sampling probe. The main technical means is to fix one sampling point, and through the stepper motor and the connecting skeleton structure, synchronously control the position changes of the other three sampling points, so that the structural form and layout of the sampling probe remain unchanged, and only the spacing of the sampling points is changed to adapt to different application scenarios of concentration gradient ranges.

[0037] Technical principle: The working principle of the four-point variable-spacing three-dimensional differential sampling probe for the gas concentration field gradient vector of the present invention (hereinafter referred to as: three-dimensional sampling probe) is as follows: Taking a sampling point S0 as the main sampling point, the sampling transmission pipeline is arranged in a straight line, constituting the fixed central axis S0P0 of the three-dimensional sampling probe. P0 is the reference point of the three-dimensional sampling probe and also the fixed convergence point of the four-way gas sampling pipelines; the other three points S1, S2, and S3 are dispersed sampling points, evenly distributed in an umbrella shape. The spatial position relationship of the three sampling points S1, S2, and S3 is an equilateral triangle S1S2S3. The fixed central axis passes through the center P1 of this equilateral triangle and is perpendicular to it, thus forming a regular tetrahedral sampling space layout; the gas transmission pipelines of the three sampling points S1, S2, and S3 are arc-shaped, that is, S1, S2, and S3 are arc-shaped to the reference point P0, as Figure 2The solid line part of the middle icon shown forms a four-point three-dimensional sampling probe with a shorter spacing. Since the positional relationships of the three sampling points S1, S2, and S3 are of the same type, their positions are associated through three sets of connecting skeletons. By controlling the connecting skeletons with a stepping motor, the position of point P1 is transformed, and then the positions of the three sampling points S1, S2, and S3 are synchronously adjusted and controlled, and the equilateral triangle positional relationship of S1, S2, and S3 is always maintained. Its control mechanism is similar to the opening form of an umbrella, and the central position P1 of the triangle is controlled to move along the fixed central axis to ensure that the sampling probe forms a regular tetrahedron structure, realizing that the distances from the main sampling point S0 to the three sampling points S1, S2, and S3 are always the same, and the distances between the three sampling points S1, S2, and S3 change synchronously with each other, thereby forming a synchronous adaptive change in the spacing of the three-dimensional sampling probe, as Figure 2 The dashed line part shown in the middle icon is the effect after the spacing synchronously increases. By using the above adjustment and control, a four-point three-dimensional sampling probe with variable spacing is realized, and the spacing can be continuously adjusted within a certain range to adapt to the detection requirements of different concentration gradients.

[0038] Technical structure: The variable-spacing three-dimensional sampling probe is composed of nine types of components, including a gas sampling pipeline 11, a fixed main sleeve 2, an intermediate moving slider 42, a support rod 51, a sleeve clamp 71, a manifold base 9, a stepping motor 81 and a screw shaft 82, a rotating shaft piece, etc., as Figure 2 shown, which are respectively:

[0039] The function of the gas sampling pipeline is to transmit the gas to be sampled, and the material is selected as elastic plastic for easy bending and recovery; it includes a main sampling pipeline 10 and three dispersed sampling pipelines 11. Figure 2 The dashed line in the middle indicates the layout position of the dispersed sampling pipelines, and the three dispersed sampling pipelines 11 together form an umbrella-shaped uniform distribution.

[0040] The function of the fixed main sleeve 2 is to limit the main sampling pipeline 10 and provide a positioning track for the stepping motor and the slider. Its main structure is a long hollow cylindrical tube, and a long key limiting groove is opened on the outer side of the cylindrical tube to limit the positioning of the slider and prevent its circumferential shaking. Its cross-section is as Figure 3 shown. The main sampling pipeline 10 passes through the fixed main sleeve 2; it is firmly connected to the bottom fixed slider 41 and the top fixed slider 43, and its position is at both ends of the fixed main sleeve 2, and the bottom is firmly connected to the manifold base 9.

[0041] The function of the rotating dispersed sleeve 31 is to limit the corresponding dispersed sampling pipeline 11 and perform rotation around the bottom fixed slider 41. The rotating dispersed sleeve 31 is an arc-shaped hollow cylindrical tube, and a long hole is opened on the lower side of the middle part, and the dispersed sampling pipeline 11 passes through this hole, as Figure 2 shown. The middle part of the rotating dispersed sleeve 31 is firmly connected to the sleeve clamp 71, and the lower part of the rotating dispersed sleeve 31 is firmly connected to the first rotating shaft piece 611.

[0042] The function of the slider is to provide limitations for the stepper motor 81 and its screw shaft 82, including the bottom fixed slider 41, the middle moving slider 42, and the top fixed slider 43. The bottom fixed slider 41 has the same structure as the middle moving slider 42. As Figure 5 shown, there are two protruding limit key blocks 421 inside, which match the limit slots 21 of the fixed main sleeve 2. The outside includes three pairs of circumferentially evenly distributed limit ears 422 and protruding fixed blocks. The three pairs of limit ears 422 cooperate with the rotating shaft piece, as Figure 4 shown in the left cross-section; the protruding fixed block is arranged between two pairs of limit ears, opposite to the position of the other pair of limit ears, and has a threaded hole 423 in the middle, which is connected to the stepper motor 81 and its screw shaft 82. The bottom fixed slider 41 is fixed to the bottom end of the fixed main sleeve 2, and the stepper motor 81 is fixed on the bottom fixed slider 41; the middle moving slider 42 is arranged in the middle of the fixed main sleeve 2 and can move linearly up and down along the fixed main sleeve 2. The top fixed slider 43 is a simple form of the middle moving slider 42, without three pairs of limit ears. As Figure 5 shown, its position is fixed to the top of the fixed main sleeve 2 and limits the end position of the screw shaft 82 to prevent its deflection and shaking.

[0043] Three support rods 51 are used to connect the middle moving slider 42 and three rotating and dispersing sleeves 31 through the rotating shaft piece. The support rods 51 are straight pipes with two openings at both ends, and are fixedly sleeved and fixed with the rotating shaft piece.

[0044] There are three groups of rotating shaft pieces, three in each group, with the same structure, which are used to flexibly achieve the rotating layout. The first group of rotating shaft pieces 611 is used to connect the rotating and dispersing sleeve 31 and the bottom fixed slider 41, the second group of rotating shaft pieces 621 is used to connect the support rod 15 and the middle moving slider 42, and the third group of rotating shaft pieces 631 is used to connect the support rod 51 and the rotating and dispersing sleeve 31. Its structure is as Figure 6 shown, and its end is fixedly sleeved and fixed with other components. The central hole is used to connect the limit ear of the slider 4 and the sleeve clamp 71.

[0045] There are three sleeve clamps 71, which are used to connect the three rotating and dispersing sleeves and the three support rods 51. They are tightly clamped in the middle of the rotating and dispersing sleeve 31 and are connected to the rotating shaft piece class, as Figure 2 shown.

[0046] The stepper motor 81 and the screw shaft 82 are a set of matching positioning devices, which are respectively connected to the three groups of sliders, as Figure 2 shown.

[0047] The manifold base 9 is located at the root of the probe, which is used to fix the fixed main sleeve 2 and the bottom fixed slider 41, and collect and fix the main sampling pipeline 10 and multiple dispersed sampling pipelines 11. At the same time, it can be connected to other external control mechanisms. Its structure is as Figure 8As shown, it passes through the main sampling pipeline 10 in the middle. The three groups of peripheral holes are the same and pass through three dispersion sampling pipelines 11 respectively. There is also a perforation for the control and power supply lines of the stepping motor 81 at the lower part.

[0048] The above structure together constitutes a four-point variable pitch three-dimensional sampling probe. The main working mechanism is that through the rotation of the stepping motor, it drives the moving slider to move linearly along the main sleeve, and synchronously drives the position changes of the dispersion support rod, the dispersion sleeve and the dispersion sampling hose, so as to realize the synchronous change of the sampling point position.

[0049] The present invention has been described exemplarily in combination with the accompanying drawings. Obviously, the implementation of the present invention is not limited by the above-mentioned manner. As long as various improvements are made by adopting the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A multi-point variable-spacing three-dimensional differential sampling probe for the gradient vector of a gas concentration field, characterized in that: It includes N sampling points, where N ≥ 4. One sampling point S0 is fixedly set at the first height, and the remaining N - 1 sampling points are all located at the second height. The N - 1 sampling points at the second height can move synchronously closer to or farther away from the sampling point S0 at the first height, so that the interior angles of the polygon formed by the N - 1 sampling points at the second height remain unchanged, but the area of the polygon will increase or decrease in multiples to adapt to application scenarios with different concentration gradient ranges.

2. The multi-point variable-spacing three-dimensional differential sampling probe for the gas concentration field gradient vector according to claim 1, characterized in that: The N - 1 sampling points at the second height form a regular polygon, and the line S0P1 formed by the center P1 of the regular polygon and the sampling point S0 is perpendicular to the regular polygon.

3. The multi-point variable-spacing three-dimensional differential sampling probe for the gas concentration field gradient vector according to claim 2, wherein: When N = 4, S1, S2, and S3 at the second height form an equilateral triangle, and S0, S1, S2, and S3 form a regular pyramid.

4. The multi-point variable-spacing three-dimensional differential sampling probe for the gas concentration field gradient vector according to claim 2, characterized in that: The sampling point S0 is located at the end of the main sampling pipe (10), and the sampling points S1, S2, and S3 are respectively located at the ends of three decentralized sampling pipes (11). The main sampling pipe (10) penetrates and fixes the main sleeve (2). An intermediate moving slider (42) is provided on the fixed main sleeve (2). The intermediate moving slider (42) can axially move along the fixed main sleeve (2) under the action of a first transmission device. The intermediate moving slider (42) makes the sampling points S1, S2, and S3 move synchronously under the action of three second transmission devices.

5. The multi-point variable-spacing three-dimensional differential sampling probe for the gas concentration field gradient vector according to claim 4, characterized in that: Each of the second transmission devices includes a support rod (51) and a rotating decentralized sleeve (31). One end of the support rod (51) is hinged to the intermediate moving slider (42) through a second rotating shaft piece (621), and the other end of the support rod (51) is hinged to the rotating decentralized sleeve (31) through a third rotating shaft piece (631). The decentralized sampling pipe (11) passes through the rotating decentralized sleeve (31). One end of the rotating decentralized sleeve (31) is hinged to the bottom fixed slider (41) through a first rotating shaft piece (611). The lower end of the fixed main sleeve (2) is fixed to the bottom fixed slider (41). The support rod (51), the rotating decentralized sleeve (31), and the fixed main sleeve (2) form a triangle.

6. The multi-point variable-spacing three-dimensional differential sampling probe for the gas concentration field gradient vector according to claim 5, wherein: The rotating decentralized sleeve (31) is tightly connected to the sleeve clamp (71), and the other end of the support rod (51) is connected to the sleeve clamp (71) through a third rotating shaft piece (631).

7. The multi-point variable-spacing three-dimensional differential sampling probe for the gas concentration field gradient vector according to claim 5, wherein: The first transmission device includes a stepping motor (81) and a screw shaft (82). A top fixed slider (43) is fixed to the upper end of the fixed main sleeve (2). One end of the screw shaft (82) is connected to the top fixed slider (43) through a bearing, and the other end of the screw shaft (82) is connected to the stepping motor (81). The stepping motor (81) is installed on the bottom fixed slider (41). The protruding fixed block of the intermediate moving slider (42) has a threaded hole (423). The screw shaft (82) passes through the threaded hole (423) and can make the intermediate moving slider (42) axially move along the screw shaft (82) when rotating.

8. The multi-point variable-spacing three-dimensional differential sampling probe for the gas concentration field gradient vector according to claim 7, characterized in that: The outside of the intermediate moving slider (42) includes three pairs of circumferentially evenly distributed limiting ears (422), and each of the three pairs of limiting ears (422) cooperates with a rotating shaft piece.

9. The multi-point variable-distance three-dimensional differential sampling probe for the gas concentration field gradient vector according to claim 8, characterized in that: The bottom fixed slider (41) has the same structure as the middle moving slider (42), and both are internally provided with two protruding limit key blocks (421), which are matched with the limit slots (21) of the fixed main sleeve (2).

10. The multi-point variable-spacing three-dimensional differential sampling probe for the gas concentration field gradient vector according to claim 9, characterized in that: It further includes a header base (9), and the header base (9) is located at the root of the probe, and is used for fixing the main sleeve (2) and the bottom fixed slider (41), and collecting and fixing the main sampling pipeline (10) and a plurality of dispersed sampling pipelines (11).

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