A steering gear and its design method, a liquid level measurement system and method

Abstract

The present application discloses a steering device and its design method, a liquid level measurement system and method, relating to the technical field of liquid level measurement. The steering device includes a plane reflecting surface and a parabolic reflecting surface. The present application utilizes the combined technology of the plane reflecting surface and the parabolic reflecting surface to extend the parabolic focusing steering device technology that could only be used on vertical tanks to spherical tanks, sausage tanks and other special-shaped tanks, so that the main beam of the mechanical vibration wave emitted by the probe installed at any position and at any angle on the tank body all becomes a parallel beam without divergence loss and vertically shoots upward to the liquid surface in the tank, and focuses and reflects the liquid surface echo to the probe, increasing the intensity of the echo signal, achieving the effects of stable and accurate measurement of the liquid level in the tank, and moreover, the volume of the steering device can be reduced.

Description

Technical Field

[0001] This application relates to the technical field of liquid level measurement, and particularly to a steering gear and its design method, a liquid level measurement system and method. Background Art

[0002] The focusing type external liquid level gauge for measuring the liquid level from the outside of a vertical tank disclosed in Patent ZL 202210413543.0 "Determination Method, System, Reflector, External Liquid Level Gauge for Vertical Tank and Its Installation Method" installs a probe outside the side wall of the vertical tank to emit ultrasonic signals into the vertical tank. The ultrasonic waves penetrate the side wall of the vertical tank and enter the liquid in the vertical tank, and are directed towards the parabolic focusing steering gear. After being reflected by the parabolic energy-gathering steering gear, they are parallel and non-scattered and attenuated towards the liquid surface, and then are reflected by the liquid surface and directed towards the focusing steering gear. After being reflected by the focusing steering gear, they are focused and directed towards the position on the inner side of the side wall of the vertical tank where the ultrasonic waves were originally emitted, penetrate the tank wall and are received by the probe that emits the ultrasonic waves. According to the difference between the emission time and the reception time of the ultrasonic signal by the probe and the sound velocity of the ultrasonic waves in the liquid to be measured, the liquid level of the vertical tank is calculated. The sound velocity of the ultrasonic waves is calculated by measuring the length of the calibrator in the known vertical tank or the diameter of the vertical tank. This focusing steering gear method on the vertical tank enhances the ultrasonic echo signal by dozens of times compared with the method without using the parabolic focusing steering gear for reflection, and the signal is stable, thus solving the long-existing drawbacks of weak, intermittent, and unstable measurement of the liquid level echo signal by the external liquid level gauge. However, this focusing steering gear technology can only install the probe on the side wall of the vertical tank, so this focusing steering gear technology can only be used for vertical tanks and cannot be used for spherical tanks, sausage tanks, and other special-shaped tanks. Summary of the Invention

[0003] The purpose of this application is to provide a steering gear and its design method, a liquid level measurement system and method, which can improve the intensity of the echo signal and avoid flickering to improve stability during the liquid level measurement of spherical tanks, sausage tanks, and other special-shaped tanks.

[0004] To achieve the above purpose, this application provides the following solutions:

[0005] In a first aspect, the present application provides a steering device, comprising: a planar reflecting surface and a parabolic reflecting surface; the planar reflecting surface is configured to reflect the main beam of a mechanical vibration wave to form a primary reflected beam; the parabolic reflecting surface is located on the transmission path of the primary reflected beam and is configured to reflect the primary reflected beam to form a secondary reflected beam, the secondary reflected beam being a parallel beam and the direction of the secondary reflected beam being vertically upward; wherein, the mirror symmetry point of a first preset point T with respect to the planar reflecting surface coincides with the focus of the parabolic reflecting surface; the first preset point T is the intersection point of the central axis of the mechanical vibration wave main beam and the inner wall of the to-be-measured tank when the mechanical vibration wave main beam passes through the tank body; the central axis of the primary reflected beam lies in a horizontal plane; the central axis of the primary reflected beam intersects the planar reflecting surface at a first characteristic point Δ and intersects the parabolic reflecting surface at a second characteristic point O; the distance between the first characteristic point Δ and the second characteristic point O is less than p, where p is the focal length of the parabolic reflecting surface.

[0006] In a second aspect, the present application provides a liquid level measurement system, comprising: a measurement probe and the above-mentioned steering device; during measurement, the measurement probe is arranged outside the to-be-measured tank and is configured to emit a mechanical vibration wave into the to-be-measured tank; wherein, the main beam of the emitted mechanical vibration wave is the main beam of the mechanical vibration wave; the steering device is arranged inside the to-be-measured tank, and the planar reflecting surface of the steering device is located in the emission direction of the main beam of the mechanical vibration wave.

[0007] In a third aspect, the present application provides a liquid level measurement method, which applies the above-mentioned steering device. The liquid level measurement method comprises: arranging the measurement probe at a measurement position on the outer wall of the to-be-measured tank; installing the steering device inside the to-be-measured tank such that the planar reflecting surface of the steering device is located in the emission direction of the measurement probe, and the parabolic reflecting surface is located on the transmission path of the primary reflected beam and the parabolic reflecting surface can reflect the primary reflected beam to form a vertically upward secondary reflected beam; wherein, the primary reflected beam is obtained by the planar reflecting surface reflecting the main beam of the mechanical vibration wave; the emission direction is perpendicular to the tangent plane at the measurement position on the outer wall of the to-be-measured tank; using the measurement probe to emit a mechanical vibration wave into the to-be-measured tank; the main beam of the emitted mechanical vibration wave is the main beam of the mechanical vibration wave; when the main beam of the mechanical vibration wave passes through the to-be-measured tank, the intersection point of its central axis and the outer wall of the to-be-measured tank is the measurement position, and the intersection point of its central axis and the inner wall of the to-be-measured tank is the first preset point T; recording the time when the measurement probe emits the mechanical vibration wave and the time when the liquid level echo is received; wherein, the time when the measurement probe emits the mechanical vibration wave and the time when the liquid level echo is received are used to calculate the liquid level of the to-be-measured tank.

[0008] Fourth aspect, the present application provides a design method for the above-mentioned steering gear, and the design method includes: selecting the measurement position T1 of the to-be-measured tank body, and determining the horizontal inclination angle of the outer wall of the to-be-measured tank body at the measurement position T1 as the horizontal angle β of the outgoing end face of the mechanical vibration wave; determining the installation position and installation angle of the plane reflecting surface according to the horizontal angle β; the installation position of the plane reflecting surface is located on the emission direction of the main beam of the mechanical vibration wave; the installation angle of the plane reflecting surface is the included angle between the plane reflecting surface and the vertical direction, and its value is α / 2; wherein, α + β = 90°; the installation position is used as the first characteristic point Δ of the plane reflecting surface; according to the installation position and installation angle, determining the mirror symmetry point T' of the first preset point T with respect to the plane reflecting surface as the focus of the parabolic reflecting surface; the first preset point T is the intersection point of the central axis and the inner wall of the to-be-measured tank body when the main beam of the mechanical vibration wave passes through the to-be-measured tank body; wherein, the straight line passing through the mirror symmetry point T', the first characteristic point Δ, and the second characteristic point O is a horizontal straight line; determining the point at a distance p from the focus along the target direction as the second characteristic point O; the target direction is the direction from the focus to the first characteristic point Δ; determining the target paraboloid according to the second characteristic point O and the focus; wherein, a partial curved surface on the target paraboloid is used as the parabolic reflecting surface, or the target paraboloid is used as the parabolic reflecting surface; determining the size of the plane reflecting surface according to the installation position, installation angle and detection intensity requirement to obtain the designed plane reflecting surface; determining the size of the parabolic reflecting surface according to the target paraboloid to obtain the designed parabolic reflecting surface.

[0009] According to the specific embodiments provided by the present application, the following technical effects are disclosed in the present application:

[0010] The present application provides a steering device and its design method, a liquid level measurement system and method. The steering device of the present application includes a plane reflecting surface and a parabolic reflecting surface. The present application utilizes the combination technology of the plane reflecting surface and the parabolic reflecting surface to extend the parabolic focusing steering device technology that could only be used on vertical tanks to spherical tanks, sausage tanks and other special-shaped tanks, so that the main beam of the mechanical vibration wave emitted by the probe installed at any position and at any angle on the tank body all becomes a parallel beam without divergence loss and vertically shoots upward to the liquid surface in the tank, and reflects the liquid surface echo to the probe, increasing the intensity of the echo signal, achieving the effects of stable and accurate measurement of the liquid level in the tank, and moreover, the volume of the steering device can be reduced. Specifically, the present application uses the plane reflecting surface and the parabolic reflecting surface for two reflections, so that the main beam of the mechanical vibration wave can form a secondary reflection beam and vertically enter the liquid surface in the tank. That is, in the present application, after the main beam is steered by the steering device, it can vertically enter the liquid surface in the form of a secondary reflection beam (parallel beam). Then, compared with the prior art where there is only one point on the liquid surface perpendicular to the main beam, the secondary reflection beam obtained in the present application is perpendicular to multiple points on the liquid surface, so it can be perpendicularly reflected back to the steering device by multiple points on the liquid surface, and after being reflected by the parabolic reflecting surface and the plane reflecting surface in the steering device, it is focused on the first preset point T, and then passes through the tank body and is received by the probe. Therefore, by adopting the technical solution of the present application, the intensity of the echo signal received by the probe will be higher than the existing method, thereby increasing the intensity of the echo signal, avoiding the flicker phenomenon when the water surface fluctuates, and improving the stability.

[0011] In the present application, the following positional relationship is also satisfied among the plane reflecting surface, the parabolic reflecting surface and the mechanical vibration wave: The main beam emitted from the first preset point T (the intersection point of the central axis of the main beam of the mechanical vibration wave and the inner wall of the tank when the main beam passes through the tank body) is incident on the plane reflecting surface (intersects the plane reflecting surface at the first characteristic point Δ), and after reflection, a primary reflection beam is obtained. The parabolic reflecting surface is located on the transmission path of the primary reflection beam. The central axis of the primary reflection beam intersects the plane reflecting surface at the first characteristic point Δ and intersects the parabolic reflecting surface at the second characteristic point O. The mirror symmetry point of the first preset point T with respect to the plane reflecting surface coincides with the focus of the parabolic reflecting surface.

[0012] For the parabolic reflecting surface, the primary reflection beam is equivalent to being emitted from the mirror symmetry point of the plane reflecting surface, and this mirror symmetry point coincides with the focus of the parabolic reflecting surface, which is equivalent to directly emitting a beam from the focus to the parabolic reflecting surface. According to the characteristics of the parabola (the mechanical vibration wave passing through the focus of the parabola projects onto the parabola, and a parallel beam can be obtained), a parallel beam vertically upward can be generated.

[0013] That is, by making the mirror symmetry point coincide with the focus and reasonably installing the parabolic reflector, a parallel beam vertically upward can be generated. Moreover, the first preset point T does not necessarily lie on the same straight line as the first feature point Δ and the second feature point O. The first preset point T, the first feature point Δ, and the second feature point O can form a triangle. In this triangle, the sum of the side TΔ and the side ΔO is equal to the focal length p. According to the fact that the sum of any two sides of a triangle is greater than the third side, it can be deduced that the length of the side TO is less than p. Therefore, the horizontal distance between the first preset point T and the second feature point O is also less than the focal length p.

[0014] The first preset point T can be regarded as the emission point of the main beam inside the tank. It should be noted that if the main beam of the mechanical wave is directly emitted horizontally from the focus of the parabolic reflector without using the plane reflector (in this case, the emission point of the main beam inside the tank is the focus), the distance between the emission point and the second feature point O is equal to the focal length p). In contrast, the deflector in this application can reduce the horizontal distance between the main beam emission point and the second feature point O on the paraboloid. That is, using the deflector provided in this application is equivalent to folding the wave transmission path, and the selection of the main beam emission point position can be more flexible. Brief Description of the Drawings

[0015] Figure 1 is a schematic structural diagram of the deflector provided by an embodiment of the present application;

[0016] Figure 2 is a schematic principle diagram of using the deflector to measure the liquid level of a spherical tank by installing a probe on the right side of the manhole of the spherical tank provided by an embodiment of the present application;

[0017] Figure 3 is a schematic principle diagram of using the deflector to measure the liquid level of a spherical tank by installing a probe on the left side of the manhole of the spherical tank provided by an embodiment of the present application;

[0018] Figure 4 is a schematic principle diagram of using only the parabolic reflector to measure the liquid level of a spherical tank provided by an embodiment of the present application;

[0019] Figure 5 is a schematic principle diagram of the path folding provided by an embodiment of the present application;

[0020] Figure 6 is a schematic diagram of the parabola b in the process of generating the parabolic reflector provided by an embodiment of the present application;

[0021] Figure 7 is a schematic principle diagram for proving that the angle between the plane reflector M1 and the vertical coordinate axis TY is α / 2 provided by an embodiment of the present application;

[0022] Figure 8Schematic diagram of the principle for measuring any incident surface angle of the steering gear provided in the embodiments of the present application;

[0023] Figure 9 Schematic diagram of the principle for measuring the liquid level of a vertical tank using the steering gear provided in the embodiments of the present application;

[0024] Figure 10 Schematic diagram of the structure of the wave breakwater provided in the embodiments of the present application;

[0025] Figure 11 Schematic diagram of the principle for measuring the liquid level using a steering gear with a partially reflective surface to reduce the volume provided in the embodiments of the present application;

[0026] Figure 12 Comparison diagram of the parabolic reflector surface in two cases: the combination of a plane reflector surface and a parabolic reflector surface provided in the embodiments of the present application, and the use of a parabolic reflector surface alone;

[0027] Figure 13 Schematic diagram for determining the plane reflector surface provided in the embodiments of the present application;

[0028] Figure 14 Schematic diagram for determining the parabolic reflector surface provided in the embodiments of the present application;

[0029] Figure 15 Schematic diagram of the reflector plane of the calibrator and the support rod provided in the embodiments of the present application. Detailed implementation manners

[0030] The present application will be further described in detail below with reference to the accompanying drawings and specific implementation manners.

[0031] In an exemplary embodiment, a steering gear is provided. Please refer to Figure 1 , which includes: a plane reflector surface M1 and a parabolic reflector surface M2.

[0032] The above-mentioned plane reflector surface M1 is used to reflect the main beam of the mechanical vibration wave to form a primary reflected beam. When the main beam of the mechanical vibration wave passes through the tank body, the intersection point of its central axis and the inner wall of the tank to be measured can be referred to as the first preset point T; still please refer to Figure 1 , if the primary reflected beam is extended in the reverse direction, it can intersect at a point T', and T' can be referred to as the mirror symmetry point of the first preset point T with respect to the plane reflector surface M1. The primary reflected beam is equivalent to being emitted from the mirror symmetry point.

[0033] The above-mentioned parabolic reflecting surface M2 is located on the transmission path of the above-mentioned primary reflected beam. The mirror symmetry point T' coincides with the focus of the parabolic reflecting surface M2. The parabolic reflecting surface M2 is used to reflect the above-mentioned primary reflected beam to form a secondary reflected beam. Among them, the above-mentioned secondary reflected beam is a parallel beam, and the direction of the above-mentioned secondary reflected beam is vertically upward.

[0034] In practice, a planar reflecting part with any edge shape can be used to form the primary reflected beam, as long as the planar reflecting part has a planar reflecting surface M1. For example, a reflector with a planar reflecting surface can be used as the planar reflecting part.

[0035] Similarly, a parabolic reflecting part with any edge shape can be used to form the secondary reflected beam, as long as the parabolic reflecting part has a parabolic reflecting surface M2. For example, a parabolic panel with a parabolic reflecting surface can be used to form the secondary reflected beam.

[0036] The principle of obtaining a vertically upward secondary reflected beam by using the deflector in this application is:

[0037] The parabolic reflecting surface M2 (abbreviated as the paraboloid) is obtained by rotating a parabolic segment (a segment on the parabola) around the axis of symmetry of the parabolic segment (i.e., the axis of symmetry of the parabola). According to the mathematical properties of the parabola, a ray of light passing through its focus (a ray from the focus of the parabola to the parabola) can be reflected by the parabola into a parallel ray (a ray parallel to the axis of symmetry). This also applies to mechanical vibration waves. The focus of the parabola can be used as the focus of the paraboloid. Then, a mechanical vibration wave passing through the focus of the paraboloid and projected onto the paraboloid can obtain a parallel mechanical vibration wave. If the paraboloid is installed so that the above-mentioned axis of symmetry is in the vertical direction and the opening of the parabola corresponding to the paraboloid faces upward, the obtained parallel rays are parallel rays in the vertical direction.

[0038] At the same time, the mirror symmetry point T' coincides with the focus of the parabolic reflecting surface M2, which is equivalent to directly emitting a mechanical vibration wave from the focus to the parabolic reflecting surface. Then, according to the aforementioned properties of the paraboloid, a vertically upward parallel mechanical vibration beam can be generated.

[0039] The planar reflecting surface M1 and the parabolic reflecting surface M2 also satisfy the following description:

[0040] The central axis m2 of the primary reflected beam reflected by the planar reflecting surface M1 is located on a horizontal plane; the central axis m2 intersects the planar reflecting surface M1 at the first characteristic point Δ and intersects the parabolic reflecting surface M2 at the second characteristic point O; and the distance between the first characteristic point Δ and the second characteristic point O is less than p, where p is the focal length of the parabolic reflecting surface M2.

[0041] It should be noted that the distance between the mirror symmetry point T' and the second feature point O is the focal length p. If the distance between the first feature point Δ and the mirror symmetry point T' is represented by q, then the distance between the first feature point Δ and the second feature point O can be expressed as p - q, which is thus less than p. Since the mirror symmetry point T' coincides with the focus, the point T' and the first preset point T are mirror-symmetrically distributed with respect to the plane reflecting surface. Therefore, the distance between the first preset point T and the first feature point Δ is also equal to q.

[0042] The steering device in this embodiment can be applied to the liquid level measurement of spherical tanks, vertical tanks, and other special-shaped tanks. In the following embodiments, a spherical tank will be taken as an example for illustration.

[0043] In other embodiments of the present invention, the plane reflecting surface M1 in all the above embodiments can fully or partially reflect the main beam of the mechanical vibration wave, and the parabolic reflecting surface M2 can fully or partially reflect the primary reflected beam.

[0044] Taking full reflection as an example, the above steering device can control all the energy of the main beam of the mechanical vibration wave to be transmitted parallelly and without divergence towards the liquid surface, and receive the focused echo. In the subsequent description, ultrasonic waves will be taken as an example for illustration. However, in the technical solution of this application, the mechanical vibration wave is not limited to ultrasonic waves, and can also be sound waves, infrasonic waves, shock waves, etc. The medium for transmitting the mechanical vibration wave is various substances such as solids, liquids, supersaturated steam, gases, and plasmas. The temperature of the medium for transmitting the mechanical vibration wave can range from extremely low temperatures close to absolute zero to one hundred million degrees of the medium for thermonuclear fusion. The temperature and pressure of the medium are not limited. The condition for the steering device of this embodiment is that the sizes of the plane reflecting surface and the parabolic reflecting surface need to be larger than the wavelength of the mechanical vibration wave in the working medium to avoid diffraction and enable the formation of the main beam.

[0045] The working principle of the steering device is introduced below:

[0046] When the plane reflecting surface is used to fully reflect the main beam of the mechanical vibration wave, when this steering device is used for measuring the liquid level of the tank, it can utilize all the energy of the main beam of the mechanical vibration wave. The ultrasonic main beam with a divergence angle of 2θ0 (θ0 in this application Figure 1 is the half emission angle) emitted by the probe is reflected by the plane reflecting surface M1, and the ultrasonic signals at each point of the parabolic reflecting surface M2 after being reflected by the parabolic reflecting surface M2 are parallelly reflected on the liquid surface, and the area S is equal to the top view area of the parabolic reflecting surface M2.

[0047] When there is no liquid flowing in or out of the tank, the liquid surface is a stationary horizontal plane, as Figure 5As shown in (b), all the ultrasonic waves vertically incident on each point of the liquid surface S will be vertically reflected downward back to the parabolic reflecting surface M2, and then focused and reflected by the parabolic reflecting surface M2 towards the plane reflecting surface M1. After being reflected by the plane reflecting surface M1, they continue to be reflected along the focusing direction towards point T, and then penetrate the tank wall and are received by the probe. This realizes the focusing and reflection of all the divergent ultrasonic main beam signals emitted by the probe back to the probe.

[0048] When the liquid enters and exits the tank, the liquid surface will fluctuate, resulting in wave crests and wave troughs. Please refer to Figure 5 (a). The ultrasonic waves incident on the wave crest or wave trough can be vertically reflected back to the parabolic reflecting surface M2. Since the deflector in this application is adopted, the point perpendicular to the mechanical vibration wave on the liquid surface is no longer a single point, but covers a certain liquid surface area, with an area of S. Assume that within the liquid surface area it covers, even if the liquid surface fluctuates, at each moment within this area, there are multiple wave crest points and wave trough points, except that the positions where the wave crest points and wave trough points appear are uncertain. However, within the covered liquid surface area, the ultrasonic waves vertically incident on the liquid surface can be reflected back to the parabolic reflecting surface M2 by multiple wave crest points and wave trough points, and then reflected and focused by the parabolic reflecting surface M2 towards the plane reflecting surface M1. After being reflected by the plane reflecting surface M1, they continue to be superimposed towards point T along the focusing direction.

[0049] Assume that there are n wave crest points and wave trough points randomly at the same time within the above-mentioned covered liquid surface. n can be calculated by the formula: n = S / λ 2 , where λ is the wavelength of the measured liquid surface fluctuation, and S is the top view area of the reflecting surface. Compared with the prior art, the probe can always receive the superimposed signal of n signals reflected from n wave crest points and wave trough points at different positions on the fluctuating liquid surface, so the signal sound pressure is enhanced by n times.

[0050] It should be noted that if the focal length p of the parabolic reflecting surface increases by k times, then the top view area S of the reflecting surface increases by k 2 times, the number n of wave crest points and wave trough points on the fluctuating liquid surface reflecting the ultrasonic wave signal increases by k 2 times, and the multiple n by which the ultrasonic sound pressure superimposed and focused on the probe increases also increases by k 2 times.

[0051] The relationship between S and p is derived as follows:

[0052] Taking total reflection as an example, at the distance of the characteristic point (i.e., the second characteristic point O) of the parabolic reflecting surface M2, the minimum radius R of the vertical sectional circle of the cone of the primary reflected beam O = p×tan(θ0). The approximate top view area of the smallest circle of the area where the primary reflected beam is projected on the parabolic reflecting surface M2 is: Therefore, it can be deduced that S is proportional to the square of the focal length p. When the focal length p increases by k times, the area of the top view of the parabolic reflector M2 increases by k 2 times.

[0053] To illustrate the above technical effects, the following two sets of experiments are conducted using the above steering gear under the condition of liquid level fluctuation.

[0054] After the tank is filled with materials, in one set of experiments, when the liquid level height of the spherical tank is 3.1 meters, the amplitudes of the liquid level echo signals of the steering gear based on the embodiments of the present application and the liquid level echo signals without using the steering gear are 100 mV and 4 mV respectively. The amplitude of the echo signal using the steering gear of the present application is 100 mV / 4 mV = 25 times that of the echo signal without using the steering gear.

[0055] In another set of experiments, when the liquid level height of the spherical tank is 1.9 meters, the amplitudes of the liquid level echo signals of the steering gear based on the embodiments of the present application and the liquid level echo signals without using the steering gear are 75 mV and 3 mV respectively. The amplitude of the liquid level echo signal using the steering gear of the present application is 75 / 3 = 25 times that of the liquid level echo signal without using the steering gear.

[0056] To illustrate the above technical effects, the following experiment is conducted using the above steering gear under the condition of a stationary liquid level.

[0057] After the tank is filled with materials, in this set of experiments, when the liquid level height of the sausage tank is 1.2 meters, the amplitudes of the liquid level echo signals of the steering gear based on the embodiments of the present application and the liquid level echo signals without using the steering gear are 11000 mV and 150 mV respectively. The amplitude of the liquid level echo signal using the steering gear of the present application is 11000 / 150 ≈ 73 times that of the liquid level echo signal without using the steering gear.

[0058] Experiments prove that when the liquid level is stationary, the sound pressure of the liquid level echo received by the probe increases by 73 times, and when the liquid level fluctuates, the sound pressure of the liquid level echo received by the probe increases by 25 times. Sound pressure P is the sound pressure per unit area, and sound intensity I is the sound energy passing through a unit area per unit time. The relationship between sound intensity I and sound pressure P is I = 1 / 2P 2 / Z, that is, the sound intensity is proportional to the square of the sound pressure, where Z is the acoustic impedance. The sound pressure is increased by 25 to 73 times, and the sound intensity, that is, the sound energy, is increased by 600 to 5000 times. Such good results are due to the fact that the deflector (hereinafter referred to as the combined deflector) of the present application, which includes a plane reflector and a parabolic reflector, realizes the parallel and non-scattering lossless transmission of all the main beams of the mechanical vibration waves emitted by the probe to the liquid surface. This enables the measurement of many highly viscous and bubble-containing liquids that had large ultrasonic transmission losses and could not be measured for liquid level in the past. For example, due to its high viscosity, petroleum has a large loss of ultrasonic waves and could not be measured by an external liquid level gauge before. Now, it can be measured with a focusing deflector. Another example is a liquid ammonia spherical tank. Since the liquid ammonia gas in the spherical tank is pumped into a tank truck and the liquid ammonia liquid in the tank truck is pressed into the spherical tank, a large number of bubbles are generated in the liquid ammonia in the spherical tank when the spherical tank is filled with liquid. The ultrasonic waves for measuring the liquid level are blocked by the bubbles, resulting in no echo signal for the external liquid level gauge and it cannot work. After using the combined deflector, the propagation path of the ultrasonic waves increases, and the situation of no echo signal basically disappears. The stronger the liquid surface echo obtained, the more types of liquids that can be measured and the more complex working conditions that can be applied.

[0059] In the spherical tank, compared with using only the parabolic reflector, the combined deflector of the present application also has the following advantages:

[0060] The top view area of the parabolic reflector is approximately: The area S is proportional to the square of the focal length p.

[0061] As Figure 4 shown in (a) and (b) of Figure 4 In (a), it is a schematic diagram of the principle of using only the parabolic reflector for liquid level measurement in a spherical tank. Figure 4 In (b), it is a partial enlarged view of (a). If only the parabolic reflector is used without the plane reflector, the focal length p of the parabolic reflector will be very small. For example, when the focal length p1 = 30 mm:

[0062] The radius R1 of the top view of the parabolic reflector = p1×tan(θ0) = 5.56 mm, square centimeters.

[0063] When using the combined deflector, the focal length of the parabolic reflector can be very large. For example, when the focal length p2 = 1000 mm:

[0064] The radius R2 of the top view of the parabolic reflector = p2×tan(θ0) = 185.34 mm, and the top view area of the parabolic reflector square decimeters.

[0065] The ratio of the top - view areas of the parabolic reflectors, S1 / S2=(p1 / p2), when the focal lengths are p1 = 30 mm and p2 = 1000 mm. 2 =(30 mm / 1000 mm) 2 =0.09%. The liquid - level echo signal received by only using the parabolic reflector is reduced by 1000 times compared to the combined steering - probe of the present application.

[0066] When using the parabolic reflector alone, if the focal length p is increased, the length of the parabolic steering device will be too large.

[0067] As Figure 11 shown, when using the parabolic reflector alone, the focus of the parabolic reflector is on the inner wall of the bottom of the spherical tank directly opposite the probe, at a very low position. And the emission angle of the ultrasonic wave emitted by the probe is generally between - 30 degrees and + 30 degrees. In this case, the ultrasonic wave is equivalent to starting from the focus and obliquely irradiating (with a large angle with the horizontal line) to a very high part of the parabolic surface. Then the upper end of the parabolic reflector device will be more than 2 meters high, which will cause the upper end of the parabolic surface to be very high, thus greatly increasing the processing die cost. Moreover, in order to reduce the measurement blind area, the probe is at a very low position at the bottom of the spherical tank, and the emission angle α of the ultrasonic wave emitted by the probe is very large. The main beam of the ultrasonic wave irradiates a very small area on the upper part of the parabolic surface. So the area S of its top - view is very small, that is, the area S of the ultrasonic wave irradiating from the parabolic reflector to the liquid level is very small, and the amplification factor n of the sound pressure received by the probe and superimposed on the probe is very small.

[0068] In the above - mentioned embodiment of the present application, the plane reflector and the parabolic reflector are combined in a universal - folding manner and designed into a suitable style with a reduced volume according to the shape of the container.

[0069] In the above - mentioned embodiment of the present application, a plane reflector is provided. First, a reflection is carried out by using the plane reflector. As Figures 2 - 3 shown, the mechanical vibration wave emitted from point T is equivalent to being emitted from the mirror - symmetric point T'. And the mirror - symmetric point T' coincides with the focus of the parabolic reflector. Then, compared with using the parabolic reflector alone, the position of the focus is increased, and the mechanical vibration wave emitted from the focus can irradiate the parabolic reflector horizontally, rather than irradiating from a very low position to a very high part of the parabolic surface. Please refer to Figure 12 . It can be clearly seen that, under the same divergence angle, for the parabolic reflector M2 of the combined steering device of the present application, compared with the parabolic reflector M2~ used alone, its upper end is significantly reduced, and the size is also significantly reduced. When the focal length of the parabolic reflector of the combined steering device is 1000 mm, the highest end of the parabolic reflector is lower than 500 mm, within a suitable range for use.

[0070] As Figure 1As shown, the embodiment of the present application is provided with a full-sound energy combined reflection deflector based on a plane reflection surface and a parabolic reflection surface to project all the sound energy of the main ultrasonic beam emitted by the probe vertically toward the liquid surface, thereby achieving the installation of a large-area parabolic reflection surface in a very small space with very low processing mold costs, so that the sound pressure is greatly increased by a factor n.

[0071] The combined diverter in this embodiment solves the problem that when an external liquid level gauge is used to measure the liquid level in a spherical tank, the liquid surface echo signal received by the probe is weak when static, flickers when fluctuating, appears sometimes and sometimes not, is weak and unstable. It also solves the problem that when only a parabolic focusing diverter is used, the area of the ultrasonic wave projected onto the liquid surface is very small and the echo is very weak, and the parabolic reflector is very high, making it extremely difficult and expensive to process the mold for a large-scale precision curved reflector and impossible to achieve.

[0072] In an exemplary embodiment, a liquid level measurement system is provided for measuring the liquid level in a spherical tank from the outside using ultrasonic waves. Figure 1 As shown, it exemplarily includes: a measuring probe and the above-mentioned deflector; during measurement, the measuring probe (hereinafter referred to as the probe) can be set on the outside of the tank to be measured, for emitting mechanical vibration waves into the tank to be measured; wherein the main beam of the emitted mechanical vibration waves is the above-mentioned main beam of the mechanical vibration waves; and the deflector is set in the tank to be measured. For related descriptions, please refer to the above introduction and will not be repeated here.

[0073] In other embodiments of the present application, the liquid level measurement system may further include an external level meter host. The external level meter host is connected to the aforementioned measuring probe. The liquid surface echo signal, generated after passing through the diverter, can penetrate the tank wall and reach point T1 on the tank's outer wall. The echo signal is received by the probe, converted into an electrical signal, and transmitted to the external level meter host. The external level meter host calculates the liquid level h within the tank based on the time difference t2-t1 between the time t1 at which the mechanical vibration wave is transmitted to the probe and the time t2 at which the liquid surface echo is received.

[0074] For example, the formula for calculating the liquid level in the tank to be tested is:

[0075]

[0076] Among them, h is the liquid level height in the tank to be measured, t1 is the moment when the measuring probe transmits the mechanical vibration wave, t2 is the moment when the measuring probe receives the liquid surface echo, v is the speed of the mechanical vibration wave transmitted in the liquid in the tank to be measured, p is the focal length of the parabola reflector, h O is the height of the second feature point O, h O= q×sin(α), where q is the distance between the first feature point Δ and the first preset point T, α is the angle between the emission direction of the main beam of the mechanical vibration wave and the horizontal plane, the first feature point Δ is the intersection point of the central axis of the primary reflected beam and the planar reflecting surface of the deflector, the second feature point O is the intersection point of the central axis of the primary reflected beam and the parabolic reflecting surface of the deflector, the primary reflected beam is the beam after the main beam of the mechanical vibration wave is reflected by the planar reflecting surface, and the first preset point T is the intersection point of the central axis of the mechanical vibration wave main beam and the inner wall of the tank to be measured when the mechanical vibration wave main beam passes through the tank to be measured.

[0077] The velocity v of the mechanical vibration wave propagating in the liquid in the tank to be measured can be calibrated.

[0078] For calibration, in other embodiments of the present application, the liquid level measurement system in all the above embodiments may further include: a calibrator and a calibration probe;

[0079] The calibrator is located inside the tank to be measured and includes a reflecting plane.

[0080] The calibration probe is also connected to the external liquid level gauge host. The calibration probe is used to emit a calibration mechanical vibration wave towards the reflecting plane outside the tank to be measured and receive a calibration echo (the calibration echo is the calibration mechanical vibration wave reflected by the reflecting plane).

[0081] The mechanical vibration wave emitted by the calibration probe can be, for example, ultrasonic wave, infrasonic wave, etc., which is the same as the mechanical vibration wave emitted by the aforementioned measurement probe in terms of emission parameters (such as frequency, amplitude, etc.).

[0082] The emission time of the calibration mechanical vibration wave, the reception time of the calibration echo, and the preset distance L can be used to calculate the velocity v of the mechanical vibration wave propagating in the liquid in the tank to be measured;

[0083] Among them, the central axis of the main beam of the calibration mechanical vibration wave is perpendicular to the reflecting plane, so that the reflecting plane can perpendicularly reflect the main beam and be received by the calibration probe in the form of an echo.

[0084] When the main beam of the calibration mechanical vibration wave passes through the tank to be measured, the intersection point of its central axis and the inner wall of the tank to be measured can be called the second preset point S1, and the distance from the second preset point S1 to the reflecting plane can be used as the above-mentioned preset distance L.

[0085] The calibrator can be of any structure as long as it includes the above-mentioned reflecting plane.

[0086] An exemplary structure of the calibrator is introduced below, including:

[0087] A support rod and a reflecting plane. The reflecting plane can be installed in the tank to be measured through the support rod.

[0088] Specifically, the calibrator consists of three support rods of standard length and a reflection plane. The length of the support rod of the calibrator is l j An example may be 1000 mm or other lengths that are convenient for installation and calculation.

[0089] See Figure 15 One end of the support rod is fixed to point B on the reflecting plane, and the other end is installed on point A on the inner wall of the tank. The central axis of the main beam of the calibration mechanical vibration wave is perpendicular to point S2 on the plane reflecting surface. To achieve calibration, each point can meet the following conditions:

[0090] The first line segment formed by the second preset point S1 and point S2 coincides with, or is parallel and equal to, the second line segment formed by point A and point B (also referred to as point S1, point S2, point A, and point B forming a rectangle);

[0091] Under the above conditions, the aforementioned L is equal to the length of the support rod l j .

[0092] In an exemplary embodiment, a liquid level measurement method for a steering gear based on the above embodiment is provided. When the steering gear has been designed and manufactured, the liquid level measurement method includes:

[0093] Step A: Install a diverter in the tank to be tested according to the measuring position of the outer wall of the tank to be tested.

[0094] The measurement position is the aforementioned point T1, which can be referred to in the previous introduction and will not be described in detail here.

[0095] After executing step A, the planar reflecting surface of the deflector can be located in the emission direction of the probe at the measurement position, and the parabolic reflecting surface is located on the transmission path of the primary reflected beam, and the above-mentioned parabolic reflecting surface can reflect the above-mentioned primary reflected beam to form a secondary reflected beam vertically upward; wherein, the above-mentioned primary reflected beam is obtained by the plane reflecting surface reflecting the main beam of the mechanical vibration wave; the above-mentioned emission direction is perpendicular to the tangent plane at the measurement position of the outer wall of the tank to be measured.

[0096] Specifically, the plane reflective surface M1 may be installed according to an installation position and an installation angle.

[0097] For the parabolic reflector M2, its focal point can be determined first. A point on the primary reflected beam transmission path that is a distance p from the focal point can be determined as the parabolic reflector M2's mounting point (referred to as mounting point C). Alternatively, a point on the primary reflected beam transmission path that is a distance pq from point Δ can be determined as the parabolic reflector M2's mounting point C. Here, p is the focal length of the parabolic reflector M2, and q is the focal length of the aforementioned planar reflector M1.

[0098] Let the mounting point C coincide with the second characteristic point O of the parabolic reflector M2, let the parabolic reflector M2 face the primary reflected beam, and let the line connecting point Δ and point C be horizontal.

[0099] Step B: Set the probe at the measuring position on the outer wall of the tank to be measured.

[0100] When the measurement position is determined, the execution order of step A and step B can be reversed or performed in parallel, which will not be described in detail here.

[0101] Step C: Use the probe to transmit mechanical vibration waves to the tank to be tested.

[0102] Among them, the main beam of the emitted mechanical vibration wave is the above-mentioned main beam of the mechanical vibration wave; when the above-mentioned main beam of the mechanical vibration wave passes through the tank body, the intersection of its central axis and the outer wall is the above-mentioned measurement position T1, and the intersection with the inner wall of the tank body is the above-mentioned first preset point T.

[0103] Step D: Record the moment when the probe transmits the mechanical vibration wave and the moment when the liquid surface echo is received.

[0104] The time when the probe transmits the mechanical vibration wave and the time when the liquid surface echo is received are used to calculate the liquid level of the tank to be tested. For details, please refer to the above description and will not be repeated here.

[0105] In other embodiments of the present application, the above-mentioned measurement method may further include the following steps:

[0106] Step E: Calculate the liquid level in the tank to be measured based on the time when the measuring probe transmits the mechanical vibration wave and the time when the liquid surface echo is received.

[0107] Please refer to the above records and I will not repeat them here.

[0108] In the above embodiment, the steering gear has been designed and prepared. In other embodiments of the present application, the steering gear can also be designed during the measurement process.

[0109] The following is an example of a spherical tank. The above measurement method may include the following steps:

[0110] The first step is to select the measurement position T1 of the spherical tank and measure the inclination angle β between the tangent plane of the tank outer wall at point T1 and the horizontal plane.

[0111] A point around the manhole flange at the bottom of the spherical tank, near the vertical centerline of the tank, can be selected as measurement position T1. The inclination angle β between the tangent plane of the tank outer wall and the horizontal plane can be measured at this selected point. For details, please refer to the description of step S1 above and will not be repeated here.

[0112] The second step is to establish coordinate system 1.

[0113] Specifically, a right - hand three - dimensional rectangular coordinate system TXYZ is established with the first preset point T as the coordinate origin, hereinafter referred to as coordinate system 1 for short.

[0114] The third step is to determine the focal length q of the plane reflector, the first characteristic point Δ, and the focus T' of the parabolic reflector. The specific determination method can be referred to the foregoing description and will not be elaborated here.

[0115] The fourth step is to establish coordinate system 2.

[0116] Specifically, a right - hand three - dimensional rectangular coordinate system T'X'Y'Z' is established with T' as the coordinate origin, hereinafter referred to as coordinate system 2 for short.

[0117] The fifth step is to design the installation angle and installation position of the plane reflector M1.

[0118] It can be referred to the foregoing relevant description and will not be elaborated here.

[0119] The sixth step is to determine the divergence angle 2θ0 of the main beam of the probe.

[0120] The seventh step is to calculate the intersection point of the marginal ray of the main beam and the plane reflector M1 according to the divergence angle 2θ0 of the probe, which is used as the first minimum marginal position.

[0121] The eighth step is to manufacture a plane reflector plate M1' containing the plane reflector M1 based on the first minimum marginal position.

[0122] The ninth step is to define p as the length of the line segment T'O. With p as the focal length, according to the parabola formula x' 2 = 2py', input the value of x', and obtain the parabola b on the T'X'Y' coordinate plane. Rotate the parabola b horizontally around the coordinate axis T'Y' to generate the target paraboloid B.

[0123] The tenth step is to design the parabolic reflector M2 according to the target paraboloid B and manufacture a parabolic reflector plate M2' with the parabolic reflector M2.

[0124] It can be referred to the foregoing relevant description and will not be elaborated here.

[0125] The eleventh step is to manufacture auxiliary components.

[0126] Exemplarily, it may include a reflector bracket and the anti - wave mechanism mentioned later.

[0127] The twelfth step is to install the plane reflector plate M1' and the parabolic reflector plate M2' using the above - mentioned reflector bracket according to the designed installation position and installation angle to form a full - energy double - reflection deflector for the outer - side liquid level of the spherical tank. And install the above - mentioned anti - wave mechanism around the deflector.

[0128] The thirteenth step is to measure the liquid level of the spherical tank with the full - acoustic - energy deflector of the spherical tank.

[0129] For how to obtain the liquid level, please refer to the foregoing description and will not be elaborated here.

[0130] The steering gear in the above embodiments can be applied not only to spherical tanks, but also to the liquid level measurement of vertical tanks and other special-shaped tanks.

[0131] The following describes how to apply it to a vertical tank.

[0132] As Figure 8 shown, a right-handed rectangular three-dimensional coordinate system ΔX”Y”Z” is established with point Δ as the coordinate origin, simply referred to as coordinate system 3 (as Figure 8 shown, Figure 8 in (a) is the front view, Figure 8 in (b) is the left view). The horizontal coordinate axis ΔX” of coordinate system 3 is parallel to the horizontal coordinate axis T’X’ of coordinate system 2 and also parallel to the horizontal coordinate axis TX of coordinate system 1, i.e., ΔX” / / T’X’ / / T1X. The coordinate axes ΔY”, ΔX”, and ΔZ” are perpendicular to each other. The ultrasonic incident ray T1Δ is in the incident plane ΔT1X”, and the incident plane ΔTX” can rotate around the horizontal coordinate axis ΔX”. The included angle between the incident plane ΔT1X” and the vertical coordinate plane ΔX”Y” of coordinate system 3 is the incident plane angle γ (as Figure 8 shown in (b)), and the incident plane angle γ can be any angle. Let the incident plane angle γ be 0 degrees when the incident plane ΔT1X” coincides with the vertical coordinate plane ΔX”Y” of coordinate system 3, for example, in the case of a spherical tank. The incident plane angle γ is 90° when the incident plane ΔT1X” coincides with the horizontal coordinate plane ΔX”Z” of coordinate system 3, which is the case of a vertical tank, for example Figure 9 shown, Figure 9 in (a) is the top view, Figure 9 in (b) is the front view, Figure 9 in (c) is the left view. It should be noted that when applied to a vertical tank, TZ and T’Z’ in the foregoing coordinate systems 1 and 2 are vertically downward, TY is perpendicular to the TXZ plane and outward from the paper, and T’Y’ is perpendicular to the T’X’Z’ plane and outward from the paper.

[0133] In the solution of the present invention, the incident direction angle β of the ultrasonic wave emitted by the probe can vary from -30° to 30°. The incident plane angle γ can be any angle, see Figure 8 in (b). For example, for the Figures 2 - 3 shown spherical tank, it is the case where the incident angle γ = 0°. For Figure 9The vertical tank shown is the case where the incident angle γ = 90°. For a strangely shaped container with a complex shape, the incident angle γ can be other angles. As long as the angle between the normal line of the plane reflecting surface M1 and the ultrasonic incident ray TΔ is equal to the angle between the normal line and the ultrasonic outgoing ray ΔO of the plane reflecting surface M1 and is equal to α / 2, it can ensure that the central axis of the main ultrasonic beam emitted by the probe is reflected by the plane reflecting surface M1 and shoots towards the characteristic point O of the second parabolic reflecting surface M2. In view of the above, the ultrasonic direction angle β emitted by the probe can vary between -30° and +30°, that is, the angle α between the ultrasonic incident ray cone angle C emitted by the probe and the horizontal coordinate axis ΔX” of the third coordinate system can vary between +60° and -60°. Moreover, the angle between the ultrasonic incident plane ΔT1X” emitted by the probe and the vertical coordinate plane ΔX”Y” of the coordinate system 3, that is, the above-mentioned incident plane angle γ, can be any angle. As long as the angle between the normal line of the plane reflecting surface M1 and the ultrasonic incident ray TΔ is equal to the angle between the normal line and the ultrasonic outgoing ray ΔO of the plane reflecting surface M1 and is equal to α / 2, it can ensure that the central axis of the main ultrasonic beam emitted by the probe is reflected by the characteristic point Δ of the plane reflecting surface M1 and shoots towards the characteristic point O of the second parabolic reflecting surface M2. Therefore, it can be said that the deflector method of the present invention is a “universal” deflector method that can be widely applied to the requirements of various containers with complex structures such as spherical tanks, vertical tanks, and sausage tanks and can be flexibly applied.

[0134] It should be noted that in the aforementioned scheme, the measurement position (installation position) is selected first, and then design, installation, etc. are carried out.

[0135] In other embodiments of the present application, other methods can also be used for design and installation. For example, since the measured target liquid level is horizontal, the horizontal placement state of the parabolic reflecting surface M2 can be determined first, that is, the focal line T’O of the horizontally placed M2 is determined first. Then, according to the focal length of the parabolic reflecting surface M2 and the structure of the tank container, the installation position of the probe on the container is determined. Then, according to the structure of the tank container, the incident plane angle γ of the probe ultrasonic wave, the incident horizontal angle β of the probe ultrasonic wave, the distance q from the probe corresponding to the T point on the inner wall of the tank to the characteristic point Δ of the plane reflecting surface M1 are determined. The position of the characteristic point Δ in the coordinate system 1 is determined (q*cos(α), q*sin(α), 0), and the vertical angle α / 2 and the horizontal angle 90° - α / 2 of M1 are determined.

[0136] In the application of the above embodiments, taking a spherical tank as an example, when liquid enters from the bottom of the spherical tank, the liquid flowing violently into the tank causes the ultrasonic waves in the bottom layer of the liquid in the spherical tank to deviate from the original propagation direction along with the liquid flow. The powerful waves affect the liquid level measurement and also generate a large number of bubbles that block the propagation of ultrasonic waves. When the liquid is emptied, the external liquid level gauge cannot receive the return signal wave and the measurement is interrupted. When the liquid enters again, the external liquid level gauge starts to search for the liquid level again, and sometimes a false double liquid level of "secondary echo" will appear. The so-called "secondary echo" means that the ultrasonic wave echo reflected by the liquid surface is reflected back by the inner wall of the spherical tank near the probe, and then emitted towards the liquid surface again and reflected back to the probe by the liquid surface, forming a phenomenon of obtaining multiple liquid surface echo waves by emitting a single ultrasonic wave signal.

[0137] The embodiment of the present application can set a wave-proof mechanism to solve these problems. The wave-proof mechanism can form a groove-shaped space (which can be called a wave-proof groove) together with the inner wall of the tank to be measured; the deflector is arranged in the groove-shaped space.

[0138] The shape of the wave-proof mechanism can be any shape, but it needs to meet the following conditions:

[0139] Draw a first ray along a first preset direction through any point on the plane reflecting surface. The first ray has an intersection with the side wall of the wave-proof mechanism; the first preset direction is: the horizontal direction away from the parabolic reflecting surface.

[0140] Draw a second ray along a second preset direction through any point on the parabolic reflecting surface. The second ray has an intersection with the side wall of the wave-proof mechanism; the second preset direction is: the horizontal direction away from the plane reflecting surface.

[0141] Exemplarily, four flat plates are fixed around the plane reflecting plate M'1 and the parabolic reflecting plate M'2 on the periphery of the bracket to form a trapezoidal wave-proof groove. The above four flat plates are an exemplary structure of the wave-proof mechanism. The height of the parabolic reflecting plate M'2 end of the wave-proof groove is equal to the upper edge of M'2 (or can be higher than M'2), and the height of the plane reflecting plate M'1 end of the wave-proof groove is equal to the upper edge of M'1 (or can be higher than M'1), as Figure 10 shown, Figure 10 in (a) is the front view of the installation of the wave-proof groove, Figure 10 in (b) is the right view of the deflector with a wave-proof groove externally arranged, Figure 10(c) in the figure is a top view of the wave-breaking trough. The lower ends of the four flat plates of the wave-breaking trough are placed on the inner wall of the spherical tank. When the spherical tank is emptied of liquid, liquid will be stored in the wave-breaking trough. After the liquid level in the spherical tank drops to the port of the flat reflector of the wave-breaking trough, the liquid in the wave-breaking trough stops dropping rapidly when it continues to drop. During the period when the spherical tank is emptied, the external liquid level gauge device of the steering device always maintains continuous and uninterrupted automatic tracking and measurement of the liquid level. This prevents the measurement from being interrupted after the spherical tank is emptied, and the liquid level display doubles when liquid is added again to search for the liquid level again. The impact of the liquid at the bottom of the spherical tank and the generated bubbles are blocked by the wave-breaking trough and do not enter between the flat reflector M'1 and the parabolic reflector M'2, so as not to affect the normal measurement of the liquid level. There is a moderate gap between the lower edge of the wave-breaking mechanism and the bottom of the spherical tank, so that the liquid level in the wave-breaking tank drops more slowly than the liquid level outside the wave-breaking tank. When the liquid is added next time, the liquid level in the wave-breaking tank rises again. The gap at the bottom of the wave-breaking tank also allows the sediment in the liquid to flow out of the wave-breaking tank.

[0142] It should be noted that the enclosure of the wave-breaking mechanism of the present application is not limited to any shape. It is not necessary to have the four side panels mentioned above. It only needs to form a groove-shaped space and accommodate a steering gear and meet the above conditions.

[0143] The following takes a spherical tank as an example to introduce the design method of the above-mentioned diverter, which includes:

[0144] S1: Select the measurement position T1 of the tank to be measured, and determine the horizontal inclination angle of the outer wall of the tank to be measured at the measurement position T1 as the horizontal angle β of the exit end face of the mechanical vibration wave.

[0145] For example, a probe measurement position T1 (also known as a measurement point or installation position) can be selected near the manhole flange at the bottom of the spherical tank, near the vertical centerline of the tank. The horizontal inclination angle β of the tank's outer wall is also the horizontal inclination angle of the probe's working end face, and T1 is the center point of the probe's working end face.

[0146] During the actual measurement process, after the probe is installed at the measurement position, the probe can be used to transmit mechanical vibration waves, such as ultrasonic waves, to the tank to be measured.

[0147] The sound pressure of the ultrasonic wave emitted by the probe at point T1 has a main beam and a weak sidelobe group in the far field area. The central axis of the main beam penetrates the tank wall in a direction perpendicular to the tank wall and enters point T on the inner wall of the spherical tank. The divergence angle of the main beam of the ultrasonic wave emitted from point T along the normal direction of the tangent plane of the inner wall of the spherical tank into the spherical tank is 2θ0, where θ0 is the half-divergence angle. The normal of the tangent plane of the inner wall of the spherical tank at point T is the central axis of the main beam. The sound pressure of the probe emission is maximum in the direction of the central axis of the main beam, denoted as 100%. As the emission angle θ deviating from the central axis of the main beam increases, the sound pressure decreases. When the above emission angle θ is equal to the half-divergence angle θ0, the sound pressure decreases to 0. The energy of the ultrasonic wave emitted by the probe is mainly concentrated in the main beam.

[0148] As an example, the diameter D of the ultrasonic probe wafer is 45 mm, the resonance frequency f = 200 kHz, the sound velocity c of water at 20°C is 1480 m / s, and the wavelength λ = c / f = 7.4 mm. It can be calculated that the half-divergence angle θ0 of the main beam of the ultrasonic wave emitted by the probe in water is θ0 = 70λ / D = 11.5°, so the divergence angle 2θ0 = 23°.

[0149] S2: Determine the installation position and installation angle of the plane reflecting surface M1 in the deflector according to the horizontal angle β.

[0150] The deflector includes a plane reflecting surface M1 and a parabolic reflecting surface M2.

[0151] Exemplarily, the installation position and installation angle can be determined as follows: On the propagation path of the main beam of the ultrasonic wave, a point at a distance q from point T is selected as the first characteristic point Δ.

[0152] The first characteristic point Δ can be used as the installation position of the plane reflecting surface M1. In addition, point Δ is the identification point of the plane reflecting surface M1 obtained after the design is completed.

[0153] The installation angle of the plane reflecting surface can be the angle between the plane reflecting surface and the vertical direction, and its value is α / 2. Here, α is the angle between the central axis of the working end face of the probe and the horizontal coordinate axis TX of the coordinate system 1, and α = 90° - β.

[0154] The above installation angle can make the central axis of the primary reflection beam obtained by reflection from the plane reflecting surface M1 lie on a horizontal plane.

[0155] In one example, for the spherical tank, please refer to Figures 2 - 3 , for the convenience of understanding the installation angle, the following is described in conjunction with the coordinate system 1; the coordinate axis TX of the coordinate system 1 is horizontally to the right, the coordinate axis TY is vertically upward, and the coordinate axis TZ is horizontally out of the paper surface.

[0156] In Figures 2 - 3In it, the included angle between the plane reflecting surface M1 and the positive direction of the TY coordinate axis is α / 2, and it is parallel to the TZ coordinate axis. The length q can be called the focal length q of the plane reflecting surface M1.

[0157] It should be noted that in practical applications, if the probe is installed at the position T1 on the right side of the manhole along the central axis of the spherical tank, then the right side of the spherical tank wall at the probe installation position is high and the left side is low. The characteristic point Δ of the plane reflecting surface is above the left of T1, and the parabolic reflecting surface is above the right of T1. Please refer to Figure 2 ; conversely, if the probe is installed at the position T1 on the left side of the manhole along the central axis of the spherical tank, then the left side of the spherical tank wall at the probe installation position is high and the right side is low. The characteristic point Δ of the plane reflecting surface is above the right of T1, and the parabolic reflecting surface is above the left of T1. Please refer to Figure 3 . In short, the characteristic point Δ of the plane reflecting surface is always in the direction of the central axis of the spherical tank at the probe installation position T1.

[0158] According to the installation position and installation angle, a plane can be designed, and the plane reflecting surface M1 can be obtained by intercepting the plane according to certain requirements. This application will continue to introduce it later.

[0159] S3: Determine the mirror symmetry point T' of the first preset point T with respect to the plane reflecting surface M1 as the focus of the parabolic reflecting surface.

[0160] After determining the installation position and installation angle of the plane reflecting surface M1, the transmission path of the aforementioned primary reflection beam can be obtained accordingly. A point can be selected on the reverse extension line of its transmission path as the mirror symmetry point T' of the first preset point T with respect to the plane reflecting surface M1, and the distance between this point and the point Δ is equal to q.

[0161] Exemplarily, please refer to Figure 2 and Figure 3 , and the point with a distance equal to q from the point Δ along the negative direction of the TX coordinate axis (this negative direction is opposite to the transmission path of the primary reflection beam) can be determined as the point T'.

[0162] S4: Determine the second characteristic point O of the parabolic reflecting surface M2.

[0163] The point with a distance of p from the focus along the target direction can be used as the second characteristic point O. The above target direction is the direction from the focus to the point Δ.

[0164] Actually, the above target direction is consistent with the transmission path of the primary reflection beam.

[0165] For easy understanding, please refer to Figure 2 and Figure 3, the coordinate axes T’X’ of coordinate system 2 and the coordinate axes TX of coordinate system 1 are parallel to each other, that is, T’X’ / / TX, and the same direction is horizontally to the right. The coordinate axes T’X’, T’Y’, and T’Z’ are perpendicular to each other according to the right-hand three-dimensional coordinate system sequence. It can be determined that the point at a distance p from point T’ in the positive direction of the T’X’ coordinate axis in coordinate system 2 (in Figure 2 and Figure 3 , this positive direction is the above-mentioned target direction and is consistent with the transmission path of the primary reflected beam) is the second characteristic point O.

[0166] S5: Determine the target paraboloid B according to the second characteristic point.

[0167] The target paraboloid B can be obtained in the following way:

[0168] Taking point T’ as the focus, taking the distance p as the focal length, and making a parabola b through point O, as Figure 6 shown.

[0169] Rotating the parabola b horizontally with the vertical coordinate axis T’Y’ of coordinate system 2 as the rotation axis (this axis is also the axis of symmetry of the parabola b) to form the target paraboloid B.

[0170] Subsequently, a part of the curved surface can be intercepted on the target paraboloid B as the parabolic reflecting surface M2. Of course, in some cases, the target paraboloid B may also be directly used as the parabolic reflecting surface M2. The characteristic point O on the above-mentioned parabola b is the second characteristic point of the parabolic reflecting surface M2, the origin T’ of coordinate system 2 is the focus of the parabolic reflecting surface M2, and the focal length p of the parabola b is the focal length of the parabolic reflecting surface M2.

[0171] It can be seen that the ultrasonic ray along the central axis of the ultrasonic main beam is reflected by the plane reflecting surface M1 and propagates a distance p-q along the negative direction of the T’X’ coordinate axis of coordinate system 2 to the characteristic point O of the parabolic reflecting surface M2, and is reflected by the parabolic reflecting surface and vertically upward along the direction of the T’Y’ coordinate axis of coordinate system 2 towards the liquid surface. The ultrasonic signal of the central axis of the ultrasonic main beam is reflected by the liquid surface to form a liquid surface echo signal, which returns along the negative direction of the T’Y’ coordinate axis of coordinate system 2 to the characteristic point O of the parabolic reflecting surface M2, and after being reflected by the parabolic reflecting surface M2, it shoots towards the characteristic point Δ of the plane reflecting surface M1, and after being reflected by the plane reflecting surface M1, it shoots towards the origin T of coordinate system 1 (i.e., the TXYZ coordinate system).

[0172] Next, it is proved that the angle between the plane reflecting surface M1 and the vertical coordinate axis TY is α / 2. In Figure 7In it, draw an auxiliary line y parallel to the coordinate axis TY through point Δ, draw an auxiliary line s perpendicular to the line segment TΔ, and draw an auxiliary line u perpendicular to the plane mirror surface M1. The included angle between the end face of the probe and the tangent plane on the outer side of the spherical tank wall at the center point T1 of the probe end face and the parallel line of the coordinate axis TX passing through point T1 is β. Draw a perpendicular line to the spherical tank wall through point T1. The intersection point of the above perpendicular line and the inner wall of the spherical tank is point T. The extension line of the line segment T1T perpendicular to the spherical tank wall passes through point Δ. Since the line T1Δ is perpendicular to the tangent plane of the outer wall of the spherical tank passing through point T1, the included angle between the line T1Δ and the auxiliary line y parallel to the coordinate axis TY is equal to β. Since the auxiliary line s is perpendicular to the line T1Δ, the included angle between the auxiliary line s and the auxiliary line y is equal to 90° - β = α. Let the included angle between the plane mirror surface M1 and the auxiliary line y be a, the included angle between the plane mirror surface M1 and the auxiliary line s be c, and the included angle between the auxiliary line u and the coordinate axis ΔX' of the second coordinate system be d. The incident angle of the central axis of the main ultrasonic beam emitted by the probe at the identification point Δ of the plane mirror surface M1 is equal to the exit angle, that is, the included angle between the auxiliary line u and ΔX' is equal to the included angle between the auxiliary line u and TΔ, which is d. So the angles a + c = c + d = d + d = α. Therefore, the angles a = c = d = α / 2. Finally, it is obtained that the included angle between the plane mirror surface M1 and the vertical coordinate axis TY is equal to α / 2.

[0173] The following describes how to determine the sizes of the plane mirror surface and the parabolic mirror surface:

[0174] When the detection intensity requirement is to fully reflect the main beam of the mechanical vibration wave, in one example, please refer to Figure 13 , the intersection point of the marginal ray of the main beam and the target plane N can be calculated according to the divergence angle 2θ0 of the main beam of the probe to determine the first minimum marginal position D1.

[0175] The target plane N is: the plane made according to the aforementioned installation position and installation angle.

[0176] When full reflection is required, the area covering the first target area can be determined as the plane mirror surface M1. The first target area is determined by the first minimum marginal position D1. Therefore, the first minimum marginal position D1 is located at the edge of the plane mirror surface M1 or inside the plane mirror surface M1.

[0177] Correspondingly, the exemplary parabolic mirror surface can be determined in the following way:

[0178] Determine the intersection point position of the marginal ray e of the primary reflected beam and the aforementioned target paraboloid B as the second minimum marginal position D2; the size of the parabolic mirror surface can be determined on the target paraboloid B according to the second minimum marginal position D2. So that the second minimum marginal position D2 is located at the edge of the parabolic mirror surface or inside the parabolic mirror surface.

[0179] It should be noted that after determining the installation position, installation angle, size, measurement position, second feature point, focal length p, etc. of the plane reflecting surface M1, the edge ray e of the primary reflected beam can be drawn.

[0180] For example, in the case of total reflection, when the probe installation position T1 is on the right side of the center line of the spherical tank, please refer to Figure 2 , a conical surface with an angle of 2θ0 can be made along the positive direction of the horizontal coordinate axis T’X’ of the coordinate system 2 with the horizontal coordinate axis T’X’ of the coordinate system 2 as the central axis. The intersection line of this conical surface and the parabolic reflecting surface M2 is the second minimum edge position D2 of the parabolic reflecting surface M2. The central axis of the above conical surface is T’O. When the probe installation position T1 is on the left side of the center line of the spherical tank, please refer to Figure 3 , a conical surface with an angle of 2θ0 can be made along the negative direction of the horizontal coordinate axis T’X’ of the coordinate system 2 with the horizontal coordinate axis T’X’ of the coordinate system 2 as the central axis to determine the second minimum edge position D2 of the parabolic reflecting surface M2.

[0181] In other embodiments of the present application, after making a conical surface of 2θ0, the intersection line of the conical surface of 2θ0 and the parabola b (the intersection line includes part of the aforementioned second minimum edge position D2) can be used as the minimum parabolic segment, and the minimum parabolic segment can be horizontally rotated around the vertical coordinate axis T’Y’ of the coordinate system 2 to form a paraboloid, and the obtained paraboloid can be directly used as the parabolic reflecting surface M2, as Figure 14 shown.

[0182] In other embodiments of the present application, a combined deflector using a partial reflecting surface to reduce the volume can be designed, that is, it is realized by requiring partial reflection of the main beam of the mechanical vibration wave, as Figure 11 shown. The specific design methods for determining the size of the plane reflecting surface and the size of the parabolic reflecting surface are as follows:

[0183] Determine the intersection position of the edge ray of the main beam of the mechanical vibration wave emitted at the measurement position and the target plane as the first minimum edge position; the edge ray of the main beam of the mechanical vibration wave is determined based on the divergence angle of the main beam of the mechanical vibration wave; the target plane is: the plane made according to the above installation position and installation angle; for specific reference, please refer to the foregoing introduction and will not be elaborated here.

[0184] Intercept within the first target area according to the ratio of partial reflection to total reflection to obtain a plane reflecting surface that meets the requirements of partial reflection.

[0185] The design of the parabolic reflecting surface can be referred to the foregoing description and will not be elaborated here.

[0186] After the design is completed, the above deflector can be prepared.

[0187] Exemplarily, materials with acoustic impedance much greater than that of the liquid to be measured, such as steel, etc., can be used to make a plane reflector M'1 according to the plane shape of the plane reflector surface M1, and a parabolic reflector M'2 according to the parabolic shape of the parabolic reflector surface M2.

[0188] Exemplarily, a bracket Z can be made of a strong and corrosion-resistant material to fix the plane reflector M'1 and the parabolic reflector M'2. The plane reflector M'1 and the parabolic reflector M'2 are precisely installed on the bracket Z. The distance between the identification point Δ of the plane reflector M'1 and the coordinate origin T of the coordinate system 1 (i.e., the TXYZ coordinate system) is q, and the coordinates of Δ in the coordinate system 1 are (q*cos(α), q*sin(α), 0). The characteristic point Δ of the plane reflector surface is in the direction of the spherical tank center line at the probe installation position T1. When T1 is on the right side of the spherical tank center line, the characteristic point Δ of the plane reflector surface is on the left side of T1. In the coordinate system 2 (i.e., the coordinate system T'X'Y'Z'), the angle between the plane reflector M'1 and the positive direction of the horizontal coordinate axis T'X' is 90° - α / 2. When T1 is on the left side of the spherical tank center line, the characteristic point Δ of the plane reflector surface is on the right side of T1, and the angle between the plane reflector M'1 and the negative direction of the horizontal coordinate axis T'X' is 90° - α / 2. The angle between the plane reflector M'1 and the vertical coordinate axis T'Y' is α / 2. The connection line between the identification point Δ of the plane reflector M'1 and the characteristic point O of the parabolic reflector is on the horizontal coordinate axis T'X' of the second coordinate system T'X'Y'Z'. The length of the connection line ΔO from the identification point Δ of M'1 to the characteristic point O of the parabolic reflector M'2 is equal to P - q, where P is the focal length of the parabolic reflector surface and q is the distance from the coordinate origin T of the first coordinate system TXYZ to the identification point Δ of the plane reflector M'1.

[0189] The application key point of this application is that since the liquid level is horizontal, it is necessary to first determine the horizontal placement state of the second reflection surface M2, that is, to first determine the focal line T'O of the horizontally placed M2. Then, according to the focal length of the parabolic reflector surface M2 and the structure of the container, determine the installation position of the probe on the container. Then, according to the structure of the container, determine the incident plane angle γ and the incident horizontal angle β of the probe ultrasonic wave in turn, the distance q between the T point of the tank inner wall corresponding to the probe and the identification point Δ of the first reflector M1, and then determine the position of the identification point Δ in the first coordinate system (q*cos(α), q*sin(α), 0), and determine the vertical angle α / 2 of M1.

[0190] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0191] In this text, specific examples are used to elaborate on the principles and implementation manners of this application. The description of the above embodiments is only used to help understand the method and its core idea of this application. At the same time, for those of ordinary skill in the art, according to the idea of this application, there will be changes in the specific implementation manners and application scopes. To sum up, the content of this specification should not be construed as a limitation to this application.

Claims

1. A steering gear, characterized in that, The steering device includes: a planar reflecting surface and a parabolic reflecting surface; The planar reflecting surface is used to reflect the main beam of the mechanical vibration wave to form a primary reflected beam; The parabolic reflecting surface is located on the transmission path of the primary reflected beam and is used to reflect the primary reflected beam to form a secondary reflected beam. The secondary reflected beam is a parallel beam, and the direction of the secondary reflected beam is vertically upward; Wherein, the mirror symmetry point of the first preset point T with respect to the planar reflecting surface coincides with the focus of the parabolic reflecting surface; the first preset point T is the intersection point of the central axis of the mechanical vibration wave main beam and the inner wall of the tank to be measured when the mechanical vibration wave main beam passes through the tank body; The central axis of the primary reflected beam is located on a horizontal plane; the central axis of the primary reflected beam intersects the planar reflecting surface at a first characteristic point Δ and intersects the parabolic reflecting surface at a second characteristic point O; the distance between the first characteristic point Δ and the second characteristic point O is less than p, where p is the focal length of the parabolic reflecting surface.

2. The steering gear according to claim 1, characterized in that The included angle between the planar reflecting surface and the vertical direction is α / 2, where α + β = 90°, and β is the horizontal angle of the emission end face of the mechanical vibration wave main beam.

3. The steering gear according to claim 1, characterized in that, The planar reflecting surface is used to reflect all or part of the mechanical vibration wave main beam, and the parabolic reflecting surface is used to reflect all or part of the primary reflected beam.

4. The steering gear according to claim 1, characterized in that, The distance between the focus and the first characteristic point Δ is q, the distance between the first characteristic point Δ and the first preset point T is q, and the distance between the first characteristic point Δ and the second characteristic point O is p - q, where q is less than p.

5. A liquid level measurement system, characterized in that, The liquid level measurement system includes: a measurement probe and the steering device according to any one of claims 1-4; During measurement, the measurement probe is arranged outside the tank to be measured and is used to emit a mechanical vibration wave into the tank to be measured; wherein, the main beam of the emitted mechanical vibration wave is the mechanical vibration wave main beam; The steering device is arranged in the tank to be measured, and the planar reflecting surface of the steering device is located in the emission direction of the mechanical vibration wave main beam.

6. The liquid level measurement system according to claim 5, characterized in that, The liquid level measurement system further includes: an external liquid level gauge main unit; The external liquid level gauge main unit is connected to the measurement probe; The external liquid level gauge main unit is used to calculate the liquid level in the tank to be measured according to the time when the measurement probe emits the mechanical vibration wave and the time when the liquid surface echo is received.

7. The liquid level measurement system according to claim 6, characterized in that, The formula for calculating the liquid level in the tank to be measured is: Wherein, h is the liquid level height in the tank to be measured, t1 is the moment when the measuring probe emits a mechanical vibration wave, t2 is the moment when the measuring probe receives the liquid surface echo, v is the transmission speed of the mechanical vibration wave in the liquid in the tank to be measured, p is the focal length of the parabolic reflector, h O is the height of the second feature point O, h O = q×sin(α), q is the distance between the first feature point Δ and the first preset point T, α is the angle between the emission direction of the main beam of the mechanical vibration wave and the horizontal plane, the first feature point Δ is the intersection of the central axis of the primary reflection beam and the plane reflector of the deflector, the second feature point O is the intersection of the central axis of the primary reflection beam and the parabolic reflector of the deflector, the primary reflection beam is the beam after the main beam of the mechanical vibration wave is reflected by the plane reflector, and the first preset point T is the intersection of the central axis and the inner wall of the tank to be measured when the main beam of the mechanical vibration wave passes through the tank to be measured.

8. The liquid level measurement system according to claim 6, characterized in that, The liquid level measurement system further includes: a calibrator and a calibration probe; the calibrator includes a reflecting plane; The calibrator is located in the tank to be measured; The calibration probe is connected to the external liquid level gauge main unit. The calibration probe is used to emit a calibration mechanical vibration wave to the reflecting plane outside the tank to be measured and receive a calibration echo; the calibration echo is the calibration mechanical vibration wave reflected by the reflecting plane; The emission time of the calibration mechanical vibration wave, the reception time of the calibration echo, and a preset distance L are used to calculate the velocity v of the mechanical vibration wave transmitted in the liquid in the tank to be measured. Wherein, the central axis of the main beam of the mechanical vibration wave for calibration is perpendicular to the reflection plane; the preset distance L is the distance from the second preset point S1 to the reflection plane; The second preset point S1 is: the intersection point of the central axis of the main beam of the mechanical vibration wave for calibration and the inner wall of the tank to be measured when the main beam passes through the tank to be measured.

9. The liquid level measurement system according to claim 8, wherein The reflection plane is installed in the tank to be measured through a support rod; wherein, one end of the support rod is fixed at a point A on the inner wall of the tank to be measured, and the other end is connected to the reflection plane at point B; The central axis of the main beam of the mechanical vibration wave for calibration is perpendicular to a point S2 on the plane reflection surface; The first line segment formed by the second preset point S1 and point S2 coincides with, or is parallel and equal to, the second line segment formed by point A and point B; The preset distance L is equal to the length of the support rod.

10. The liquid level measurement system according to any one of claims 5-9, characterized in that, The liquid level measurement system further includes: a wave prevention mechanism; The wave prevention mechanism can form a trough-shaped space together with the inner wall of the tank to be measured; the deflector is arranged in the trough-shaped space; Wherein, a first ray is drawn along a first preset direction through any point on the plane reflection surface, and the first ray intersects with the side wall of the wave prevention mechanism; the first preset direction is: the horizontal direction away from the parabolic reflection surface; A second ray is drawn along a second preset direction through any point on the parabolic reflection surface, and the second ray intersects with the side wall of the wave prevention mechanism; the second preset direction is: the horizontal direction away from the plane reflection surface.

11. The liquid level measurement system according to claim 8 or 9, wherein The external liquid level gauge host is further configured to: according to the preset distance L, the time t'1 when the calibration probe emits the calibration mechanical vibration wave, and the time t'2 when the calibration mechanical vibration wave reflected by the reflection plane is received, use the following formula to calculate the velocity v of the mechanical vibration wave transmitted in the liquid in the tank to be measured; v = 2L / (t'2 - t'1).

12. A liquid level measurement method, characterized in that, The liquid level measurement method uses the deflector according to any one of claims 1-4, and the liquid level measurement method includes: Setting the measurement probe at the measurement position on the outer wall of the tank to be measured; Installing a deflector in the tank to be measured so that the plane reflection surface of the deflector is in the emission direction of the measurement probe, and the parabolic reflection surface is on the transmission path of the primary reflection beam, and the parabolic reflection surface can reflect the primary reflection beam to form a vertically upward secondary reflection beam; wherein, the primary reflection beam is obtained by reflecting the main beam of the mechanical vibration wave by the plane reflection surface; the emission direction is perpendicular to the tangent plane at the measurement position on the outer wall of the tank to be measured; Using the measurement probe to emit a mechanical vibration wave to the tank to be measured; the main beam of the emitted mechanical vibration wave is the main beam of the mechanical vibration wave; when the main beam of the mechanical vibration wave passes through the tank to be measured, the intersection point of its central axis and the outer wall of the tank to be measured is the measurement position, and the intersection point with the inner wall of the tank to be measured is the first preset point T; Recording the time when the measurement probe emits the mechanical vibration wave and the time when the liquid level echo is received; Among them, the moment when the measurement probe emits a mechanical vibration wave and the moment when the liquid surface echo is received are used to calculate the liquid level of the tank to be measured.

13. A design method of a steering gear according to any one of claims 1-4, characterized in that, The design method includes: Select the measurement position T1 of the tank to be measured, and determine the horizontal inclination angle of the outer wall of the tank to be measured at the measurement position T1 as the horizontal angle β of the outgoing end face of the mechanical vibration wave; Determine the installation position and installation angle of the plane reflecting surface according to the horizontal angle β; the installation position of the plane reflecting surface is on the emission direction of the main beam of the mechanical vibration wave; the installation angle of the plane reflecting surface is the included angle between the plane reflecting surface and the vertical direction, and its value is α / 2; where α + β = 90°; the installation position is used as the first characteristic point Δ of the plane reflecting surface; According to the installation position and installation angle, determine the mirror symmetry point T' of the first preset point T with respect to the plane reflecting surface as the focus of the parabolic reflecting surface; the first preset point T is the intersection point of the central axis and the inner wall of the tank to be measured when the main beam of the mechanical vibration wave passes through the tank to be measured; among them, the straight line passing through the mirror symmetry point T', the first characteristic point Δ and the second characteristic point O is a horizontal straight line; Determine the point at a distance p from the focus along the target direction as the second characteristic point O; the target direction is the direction from the focus to the first characteristic point Δ; Determine the target paraboloid according to the second characteristic point O and the focus; where a partial curved surface on the target paraboloid is used as the parabolic reflecting surface, or the target paraboloid is used as the parabolic reflecting surface; Determine the size of the plane reflecting surface according to the installation position, installation angle and detection intensity requirement to obtain the designed plane reflecting surface; Determine the size of the parabolic reflecting surface according to the target paraboloid to obtain the designed parabolic reflecting surface.

14. The design method of the steering gear according to claim 13, characterized in that, When the detection intensity requirement is to fully reflect the main beam of the mechanical vibration wave, determining the size of the plane reflecting surface according to the installation position, installation angle and detection intensity requirement specifically includes: Determine the intersection position of the edge ray of the main beam of the mechanical vibration wave emitted at the measurement position and the target plane as the first minimum edge position; the edge ray of the main beam of the mechanical vibration wave is determined based on the divergence angle of the main beam of the mechanical vibration wave; the target plane is the plane made according to the installation position and installation angle; Determine the size of the plane reflecting surface on the target plane according to the first minimum edge position so that any of the first minimum edge positions is located at the edge of the plane reflecting surface or inside the plane reflecting surface.

15. The design method of the steering gear according to claim 13, characterized in that, When the detection intensity requirement is to partially reflect the main beam of the mechanical vibration wave, determining the size of the plane reflecting surface according to the installation position, installation angle and detection intensity requirement specifically includes: Determine the intersection position of the edge ray of the main beam of the mechanical vibration wave emitted at the measurement position and the target plane as the first minimum edge position; the edge ray of the main beam of the mechanical vibration wave is determined based on the divergence angle of the main beam of the mechanical vibration wave; the target plane is the plane made according to the installation position and installation angle; Extract a planar reflecting surface that meets the partial reflection requirement within the first target area according to the ratio of partial reflection to total reflection; wherein, the ratio of the area of the planar reflecting surface to the area of the first target area conforms to the ratio; the first target area is an area determined on the target plane according to the first minimum edge position.

16. The design method of a steering gear according to any one of claims 13-15, characterized in that Determine the intersection position of the edge ray of the primary reflected beam with the target paraboloid as the second minimum edge position; Determine the size of the paraboloid reflecting surface on the target paraboloid according to the second minimum edge position, so that any one of the second minimum edge positions is located at the edge of the paraboloid reflecting surface or inside the paraboloid reflecting surface.

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