Steering gear and design method thereof, and liquid level measuring system and method

Abstract

The invention discloses a steering gear and a design method thereof, and a liquid level measurement system and method, and relates to the technical field of liquid level measurement. The steering gear comprises a plane reflecting surface and a paraboloid reflecting surface, and by means of the combination technology of the plane reflecting surface and the paraboloid reflecting surface, the paraboloid focusing steering gear technology which can only be used on a vertical tank originally is expanded to a spherical tank, a sausage tank and other special-shaped tanks. The main beams of mechanical vibration waves emitted by the probe installed at any position of the tank body at any angle are all changed into parallel beams which are vertically emitted upwards to the liquid level in the tank body without divergence loss, liquid level echoes are focused and reflected to the probe, the intensity of echo signals is increased, the effect of measuring the liquid level of the tank body stably and accurately is achieved, and the measurement accuracy is improved. And the size of the steering gear can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of liquid level measurement, and in particular to a steering gear and a design method thereof, and a liquid level measurement system and method. Background Art

[0002] Patent ZL 202210413543.0 "Determination method, system, reflector, vertical tank external liquid level gauge and installation method thereof" discloses a focusing type external liquid level gauge that uses ultrasound to measure the liquid level from the outside of a vertical tank. A probe is installed outside the side wall of the vertical tank to transmit an ultrasonic signal into the vertical tank. The ultrasonic wave penetrates the side wall of the vertical tank and enters the liquid in the vertical tank, and then is emitted to the parabolic focusing deflector. After being reflected by the parabolic focusing deflector, it is emitted to the liquid surface in parallel without scattering attenuation, and then reflected by the liquid surface to the focusing deflector. It is reflected and focused by the focusing deflector to the position inside the side wall of the vertical tank where the ultrasonic wave was originally emitted, and then penetrates the tank wall and is received by the ultrasonic wave emitting probe. The liquid level of the vertical tank is calculated based on the difference between the emission time of the ultrasonic signal by the probe and the reception time and the sound velocity of the ultrasonic wave in the liquid to be measured. The sound velocity of the ultrasonic wave is calculated by measuring the known length of the calibrator in the vertical tank or the diameter of the vertical tank. This focusing deflector method enhances the ultrasonic echo signal on the vertical tank by dozens of times compared with the method without parabolic focusing deflector reflection, and the signal is stable, thus solving the long-standing problem of weak, intermittent and unstable measurement of liquid level echo signals measured by external level gauges. However, this focusing deflector technology can only install the probe on the side wall of the vertical tank, so this focusing deflector technology can only be used for vertical tanks, not spherical tanks, sausage tanks and other special-shaped tanks. Summary of the invention

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

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

[0005] In the first aspect, the present application provides a deflector, comprising: a plane reflecting surface and a parabolic reflecting surface; the plane reflecting surface is used 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 used to reflect the primary reflected beam to form a secondary reflected beam, wherein 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 a first preset point T with respect to the plane reflecting surface coincides with the focus of the parabolic reflecting surface; the first preset point T is the intersection point of the center axis of the main beam of the mechanical vibration wave with the inner wall of the tank body to be measured when the main beam of the mechanical vibration wave passes through the tank body; the center axis of the primary reflected beam is located on a horizontal plane; the center axis of the primary reflected beam intersects with the plane reflecting surface at a first characteristic point Δ, and intersects with 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, wherein 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 measuring probe and the above-mentioned deflector; during measurement, the measuring probe is arranged outside the tank body to be measured, and is used to emit mechanical vibration waves into the tank body to be measured; wherein the main beam of the emitted mechanical vibration waves is the main beam of the mechanical vibration waves; the deflector is arranged inside the tank body to be measured, and the planar reflection surface of the deflector is located in the emission direction of the main beam of the mechanical vibration waves.

[0007] In a third aspect, the present application provides a liquid level measurement method, which uses the above-mentioned deflector, and the liquid level measurement method comprises: setting a measuring probe at a measuring position on the outer wall of a tank body to be measured; installing a deflector in the tank body to be measured so that a plane reflection surface of the deflector is located in the emission direction of the measuring probe, and a parabolic reflection surface is located on the transmission path of a primary reflection beam, and the parabolic reflection surface can reflect the primary reflection beam to form a secondary reflection beam pointing vertically upward; wherein the primary reflection beam is obtained by the plane reflection surface reflecting the main beam of the mechanical vibration wave; The emission direction is perpendicular to the tangent plane at the measurement position of the outer wall of the tank body to be measured; the mechanical vibration wave is emitted to the tank body to be measured by using the measuring probe; 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 body to be measured, the intersection point of its central axis with the outer wall of the tank body to be measured is the measuring position, and the intersection point with the inner wall of the tank body to be measured is the first preset point T; the time when the measuring probe emits the mechanical vibration wave and the time when the liquid surface echo is received are recorded; wherein, the time when the measuring probe emits the mechanical vibration wave and the time when the liquid surface echo is received are used to calculate the liquid level of the tank body to be measured.

[0008] In a fourth aspect, the present application provides a design method for the above-mentioned diverter, the design method comprising: selecting a measurement position T1 of a tank body to be measured, and determining a horizontal inclination angle of an outer wall of the tank body to be measured at the measurement position T1 as a horizontal angle β of the exit end face of the mechanical vibration wave; determining the installation position and installation angle of a plane reflection surface according to the horizontal angle β; the installation position of the plane reflection surface is located in the emission direction of the main beam of the mechanical vibration wave; the installation angle of the plane reflection surface is the angle between the plane reflection surface and the vertical direction, and its value is α / 2; wherein α+β=90°; the installation position is used as a first characteristic point Δ of the plane reflection surface; according to the installation position and the installation angle, determining a mirror symmetric point T' of a first preset point T with respect to the plane reflection surface as the focus of the parabolic reflection surface; the first preset point T is When the main beam of the mechanical vibration wave passes through the tank body to be tested, the intersection of its central axis and the inner wall of the tank body to be tested; 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; determine the point along the target direction at a distance p from the focus as the second characteristic point O; the target direction is the direction from the focus to the first characteristic point Δ; determine the target parabola according to the second characteristic point O and the focus; wherein, part of the curved surface on the target parabola is used as a parabola reflecting surface, or the target parabola is used as a parabola reflecting surface; determine the size of the plane reflecting surface according to the installation position, installation angle and detection intensity requirements, and obtain the plane reflecting surface after the design is completed; determine the size of the parabola reflecting surface according to the target parabola, and obtain the parabola reflecting surface after the design is completed.

[0009] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0010] The present application provides a diverter and a design method thereof, and a liquid level measurement system and method. The diverter of the present application includes a plane reflective surface and a parabolic reflective surface. The present application utilizes the combination technology of the plane reflective surface and the parabolic reflective surface to expand the parabolic focusing diverter technology that was originally only used on vertical tanks to spherical tanks, sausage tanks and other special-shaped tanks, so that the main wave beam of the mechanical vibration wave emitted by the probe installed at any position and angle of the tank body is all transformed into a parallel beam without divergence loss and vertically shoots upward to the liquid surface in the tank body, and focuses and reflects the liquid surface echo to the probe, thereby increasing the intensity of the echo signal, achieving a stable and accurate effect of measuring the tank body liquid level, and reducing the volume of the diverter. Specifically, the present application utilizes a plane reflection surface and a parabolic reflection surface for two reflections, so that the main beam of the mechanical vibration wave can form a secondary reflection beam that is incident vertically upward to the liquid surface in the tank body. That is, in the present application, after the main beam is deflected by the deflector, it can be incident vertically to the liquid surface in the form of a secondary reflection beam (parallel beam). Compared with the prior art in which only one point on the liquid surface is perpendicular to the main beam, the secondary reflection beam obtained in the present application is perpendicular to multiple points on the liquid surface, so that it can be vertically reflected back to the deflector by multiple points on the liquid surface, and then reflected by the parabolic reflection surface and the plane reflection surface in the deflector, and then focused on the first preset point T, and then passed through the tank body to be 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 that of the prior art, thereby improving the intensity of the echo signal, avoiding the flickering phenomenon when the water surface fluctuates, and improving stability.

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

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

[0013] That is, by aligning the mirror symmetry point with the focus, a vertically upward parallel beam can be generated by properly installing the parabolic reflector, and the first preset point T does not have to be in the same straight line with the first characteristic point Δ and the second characteristic point O. The first preset point T, the first characteristic point Δ and the second characteristic point O can form a triangle, in which 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 the 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 characteristic 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 in the tank. It should be noted that if the main beam of the mechanical wave is directly emitted from the focus of the parabola reflection surface in the horizontal direction without using a plane reflection surface (at this time, the emission point of the main beam in the tank is the focus), then the distance between the emission point and the second characteristic point O is equal to the focal length p). In comparison, the deflector in the present application can reduce the horizontal distance between the emission point of the main beam and the second characteristic point O on the parabola, that is, the use of the deflector provided in the present application is equivalent to folding the transmission path of the wave, and the selection of the emission point position of the main beam can be more flexible. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of the structure of the steering gear provided in the embodiment of the present application;

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

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

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

[0019] Figure 5 A schematic diagram of the principle of path folding provided in an embodiment of the present application;

[0020] Figure 6 A schematic diagram of a parabola b in the process of generating a parabolic reflecting surface provided in an embodiment of the present application;

[0021] Figure 7 A schematic diagram of the principle for proving that the angle between the plane reflection surface M1 and the vertical coordinate axis TY is α / 2 provided in the embodiment of the present application;

[0022] Figure 8A schematic diagram of the principle of measuring any incident surface angle by a deflector provided in an embodiment of the present application;

[0023] Fig. 9 A schematic diagram of the principle of using a diverter to measure the liquid level of a vertical tank provided in an embodiment of the present application;

[0024] Fig.10 A schematic diagram of the structure of the wave-breaking trough provided in an embodiment of the present application;

[0025] Fig.11 A schematic diagram of the principle of using a diverter with a partially reflective surface to reduce the volume for liquid level measurement provided in an embodiment of the present application;

[0026] Fig.12 A comparison diagram of the parabolic reflective surface in two cases where a planar reflective surface and a parabolic reflective surface are combined and the parabolic reflective surface is used alone according to an embodiment of the present application;

[0027] Fig.13 A schematic diagram of determining a planar reflective surface provided in an embodiment of the present application;

[0028] Fig.14 A schematic diagram of determining a parabolic reflective surface provided in an embodiment of the present application;

[0029] Fig.15 Schematic diagram of the calibrator reflection plane and support rods provided in an embodiment of the present application. DETAILED DESCRIPTION

[0030] The present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0031] In an exemplary embodiment, a diverter is provided, see Figure 1 , including: a plane reflecting surface M1 and a parabolic reflecting surface M2.

[0032] The plane reflection surface M1 is used to reflect the main beam of the mechanical vibration wave to form a primary reflection beam. When the main beam of the mechanical vibration wave passes through the tank, the intersection of its central axis and the inner wall of the tank to be tested can be called the first preset point T; see also Figure 1 If the first reflected beam is extended in the reverse direction, it can intersect at a point T', which can be called the mirror symmetry point of the first preset point T with respect to the plane reflection surface M1. The first reflected beam is equivalent to being emitted from the mirror symmetry point.

[0033] The parabolic reflector surface M2 is located on the transmission path of the primary reflected beam, the mirror symmetry point T' coincides with the focus of the parabolic reflector surface M2, and the parabolic reflector surface M2 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.

[0034] In practice, a plane reflection portion with any edge shape can be used to form a primary reflection beam, as long as the plane reflection portion has a plane reflection surface M1. For example, a reflection plate with a plane reflection surface can be used as the plane reflection portion.

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

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

[0037] The parabolic reflecting surface M2 (parabola for short) is obtained by rotating a parabola segment (a segment on a parabola) around the symmetry axis of the parabola segment (that is, the symmetry axis of the parabola). According to the mathematical properties of the parabola, the light rays passing through its focus (rays from the focus of the parabola to the parabola) can be reflected by the parabola to become parallel rays (rays parallel to the symmetry axis). The same applies to mechanical vibration waves. The focus of the parabola can be used as the focus of the parabola, so the mechanical vibration waves passing through the focus of the parabola are projected onto the parabola, and parallel mechanical vibration waves can be obtained. If the parabola is installed so that the above-mentioned symmetry axis is in the vertical direction and the opening of the parabola corresponding to the parabola is facing upward, the parallel rays obtained are parallel rays in the vertical direction.

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

[0039] The plane 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 plane reflecting surface M1 is located on a horizontal plane; the central axis m2 intersects with the plane reflecting surface M1 at a first characteristic point Δ, and intersects with the parabolic reflecting surface M2 at a 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 symmetric point T' and the second characteristic point O is the focal length p. If the distance between the first characteristic point Δ and the mirror symmetric point T' is expressed as q, the distance between the first characteristic point Δ and the second characteristic point O can be expressed as pq, which is less than p. Since the mirror symmetric point T' coincides with the focus, point T' and the first preset point T are mirror symmetrically distributed relative to the plane reflection surface. Therefore, the distance between the first preset point T and the first characteristic point Δ is also equal to q.

[0042] The diverter 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 description.

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

[0044] Taking total reflection as an example, the above-mentioned diverter can control the total energy of the main beam of the mechanical vibration wave to be transmitted to the liquid surface in parallel without divergence, and receive the focused reflected echo. In the subsequent description, ultrasound is used as an example for description, but in the technical solution of the present application, the mechanical vibration wave is not limited to ultrasound, and can also be sound waves, infrasound waves, shock waves, etc. The medium transmitted by the mechanical vibration wave is various substances such as solid, liquid, supersaturated steam, gas, plasma, etc. The temperature of the medium for mechanical vibration wave transmission can be from extremely low close to absolute zero to 100 million degrees of thermonuclear fusion medium, and the temperature and pressure of the medium are not limited. The condition of the diverter of this embodiment is that the size of the plane reflection surface and the parabolic reflection surface needs to be larger than the wavelength of the mechanical vibration wave in the working medium to avoid diffraction so that the main beam can be formed.

[0045] The working principle of the steering gear is described below:

[0046] When the plane reflection surface is used to fully reflect the main beam of the mechanical vibration wave, the deflector can use all the energy of the main beam of the mechanical vibration wave when measuring the tank liquid level. The divergence angle of the probe emission is 2θ0 (see Appendix 1 of this application). Figure 1 Where θ0 is the half emission angle, the ultrasonic main beam is reflected by the plane reflection surface M1 and then projected onto the parabolic reflection surface M2. The ultrasonic signals at each point are reflected by the parabolic reflection surface M2 and projected onto the liquid surface in parallel, covering an area S that is equal to the top view area of ​​the parabolic reflection surface M2.

[0047] When there is no liquid in or out of the tank, the liquid level is a static horizontal plane, such as Figure 5As shown in (b), all ultrasonic waves vertically directed to each point on the liquid surface S will be reflected vertically downward back to the parabolic reflector M2, focused and reflected by the parabolic reflector M2 to the plane reflector M1, and then reflected by the plane reflector M1 to continue to be directed to point T along the focusing direction, and then penetrate the tank wall to the probe and be received by the probe. This achieves the goal of focusing and reflecting all the divergent ultrasonic main beam signals emitted by the probe back to the probe.

[0048] When liquid is flowing into or out of the tank, the liquid level will fluctuate, resulting in peaks and troughs. Figure 5 In (a), the ultrasonic wave incident on the crest or trough can be vertically reflected back to the parabolic reflection surface M2. Due to the use of the deflector in the present application, the liquid surface perpendicular to the mechanical vibration wave is no longer a point, but covers a certain liquid surface area with an area of ​​S. It is assumed that within the liquid surface covered by it, even if the liquid surface fluctuates, there are multiple crest points and trough points in the above-mentioned area at each moment, but the positions of the crest points and trough points are uncertain. However, in the area of ​​the covered liquid surface, the ultrasonic wave vertically incident on the liquid surface can be reflected back to the parabolic reflection surface M2 by multiple crest points and trough points, and then reflected and focused by the parabolic reflection surface M2 to the plane reflection surface M1, and reflected by the plane reflection surface M1 continues to be superimposed along the focusing direction to point T.

[0049] Assuming that there are n random peaks and troughs in the liquid surface covered above, 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 reflection surface. Compared with the prior art, the probe can receive the superposition signal of n signals of n reflected echoes from n wave crest points and wave trough points at different positions on the fluctuating liquid surface at any time, and the signal sound pressure is enhanced by n times.

[0050] It should be noted that if the focal length p of the parabola reflecting surface increases by k times, the top view area S of the reflecting surface increases by k. 2 times, the number of crest points and trough points n of the wave surface reflecting the ultrasonic signal increases by k 2 times, the ultrasonic sound pressure superimposed on the probe increases by a factor of n, k 2 times.

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

[0052] Taking full reflection as an example, the minimum radius R of the vertical cross-section circle of the cone of the first reflected beam at the characteristic point (i.e., the second characteristic point O) of the parabola reflecting surface M2 is O =p×tan(θ0), the top view area of ​​the minimum circle of the area where the reflected wave beam is projected on the parabola reflecting surface M2 is approximately: Therefore, it can be deduced that S is proportional to the square of the focal length p. If the focal length p increases by k times, the top view area of ​​the parabolic reflector M2 will increase by k. 2 times.

[0053] In order to illustrate the above technical effects, the following two sets of experiments were carried out using the above-mentioned steering device under the condition of liquid level fluctuations.

[0054] After feeding into the tank, in a set of experiments, when the liquid level height of the spherical tank was 3.1 meters, the amplitudes of the liquid level echo signal of the diverter based on the embodiment of the present application and the liquid level echo signal without using the diverter were 100 mV and 4 mV respectively. The amplitude of the echo signal using the diverter of the present application is 100 mV / 4 mV = 25 times that of the echo signal without using the diverter.

[0055] In another set of experiments, when the liquid level height of the spherical tank was 1.9 meters, the amplitudes of the liquid level echo signal of the diverter based on the embodiment of the present application and the liquid level echo signal without using the diverter were 75 millivolts and 3 millivolts respectively. The amplitude of the liquid level echo signal using the diverter of the present application was 75 / 3=25 times the amplitude of the liquid level echo signal without using the diverter.

[0056] In order to illustrate the above technical effects, the following experiment was carried out using the above-mentioned steering device when the liquid surface was still.

[0057] After feeding into the tank, in this group of experiments, when the liquid level height of the sausage tank was 1.2 meters, the amplitudes of the liquid level echo signal of the diverter based on the embodiment of the present application and the liquid level echo signal without using the diverter were 11000 mV and 150 mV respectively. The amplitude of the liquid surface echo signal using the diverter of the present application is 11000 / 150≈73 times the amplitude of the liquid surface echo signal without using the diverter.

[0058] Experiments have shown that when the liquid surface is stationary, the sound pressure of the liquid surface echo received by the probe increases by 73 times, and when the liquid surface fluctuates, the sound pressure of the liquid surface 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∽73 times, and the sound intensity, that is, the sound energy, is increased by 600∽5000 times. Such a good effect can be achieved thanks to the deflector (hereinafter referred to as the combined deflector) comprising a plane reflector and a parabolic reflector of the present application, which realizes the parallel transmission of the main beam of the mechanical vibration wave emitted by the probe to the liquid surface without scattering loss. As a result, many high-viscosity and bubble-containing liquids that could not measure the liquid level in the past due to large ultrasonic transmission losses can now be measured. For example, due to its high viscosity and large ultrasonic loss, the liquid level of petroleum could not be measured by an external liquid level gauge before, but 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 extracted and 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 tank when the spherical tank is filled with liquid, and the ultrasonic wave for measuring the liquid level is blocked by the bubbles, resulting in the external liquid level gauge having no echo signal and being unable to work. After using the combined deflector, the ultrasonic propagation paths have increased, and the situation of no echo signal has basically disappeared. The stronger the liquid surface echo obtained, the more types of liquids can be measured and the more complex working conditions can be applied.

[0059] Compared with the use of a parabolic reflector alone, the combined deflector in the present application also has the following advantages in the spherical tank:

[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] like Figure 4 As shown in (a) and (b), Figure 4 (a) is a schematic diagram of the principle of using a parabolic reflector alone to measure the liquid level of a spherical tank. Figure 4 (b) is a partial enlarged view of (a). If only a parabolic reflector is used without a 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 of the top view of the parabola reflector is R1 = p1 × tan (θ0) = 5.56 mm, Square centimeters.

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

[0064] The radius of the top view of the parabola reflector is R2 = p2 × tan (θ0) = 185.34 mm, and the top view area of ​​the parabola reflector is Square decimeter.

[0065] The ratio of the top view area of ​​the parabola reflecting surface when the focal length p1 = 30 mm is compared to p2 = 1000 mm, S1 / S2 = (p1 / p2) 2 =(30 mm / 1000 mm) 2 =0.09%, using only the parabolic reflector surface reduces the liquid surface echo signal received by the combined deflector probe of the present application by 1000 times.

[0066] When a parabolic reflector is used alone, if the focal length p is increased, the length of the parabolic deflector will be too large.

[0067] like Fig.11 As shown, when the parabolic reflector is used alone, the focus of the parabolic reflector is on the inner wall of the bottom wall of the spherical tank facing the probe, which is located 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 parabola, then the high end of the parabolic reflector device will be more than 2 meters high, which will cause the upper end of the parabola to be very high, thereby greatly increasing the processing mold fee. Moreover, in order to reduce the measurement blind area, the probe is at a very low position at the bottom of the spherical tank, the ultrasonic wave emission angle α emitted by the probe is very large, and the main ultrasonic wave beam is emitted to a very small area on the upper part of the parabola, so the area S of its top view is very small, that is, the ultrasonic wave area S emitted from the parabolic reflector to the liquid surface is very small, and the sound pressure increase multiple n received by the probe and superimposed on the probe is very small.

[0068] The plane reflecting surface and the parabolic reflecting surface proposed in the above-mentioned embodiments of the present application are universally combined and folded, and are designed into a suitable style for reducing the volume according to the shape of the container.

[0069] The above embodiment of the present application sets a plane reflection surface, and uses the plane reflection surface to perform a reflection first, such as Figure 2-Figure 3 As shown, the mechanical vibration wave emitted from point T is equivalent to that emitted from the mirror symmetry point T', and the mirror symmetry point T' coincides with the focus of the parabola reflector. Compared with using the parabola reflector alone, the focus position is raised, and the mechanical vibration wave emitted from the focus can be emitted horizontally to the parabola reflector, rather than from a very low position to a very high part of the parabola. See Fig.12 It can be clearly seen that, under the condition of the same divergence angle, the parabolic reflector M2 of the combined deflector of the present application has its upper end significantly lowered and its size significantly reduced compared with the parabolic reflector M2~ used alone. When the focal length of the parabolic reflector of the combined deflector is 1000 mm, the highest end of the parabolic reflector is lower than 500 mm, which is within the range suitable for use.

[0070] like 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 and mold costs, so that the sound pressure is increased by a large multiple 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 costly 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; when measuring, the measuring probe (referred to as the probe) can be set on the outside of the tank to be measured, and is used to emit 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 liquid level meter host. The external liquid level meter host is connected to the above-mentioned measuring probe, and the liquid surface echo signal obtained after the diverter can penetrate the spherical tank wall to reach the T1 point on the outer wall of the spherical tank. The echo signal is received by the probe and converted into an electrical signal and transmitted to the external liquid level meter host. The external liquid level meter host calculates the liquid level h in the spherical tank based on the time difference t2-t1 between the moment t1 when the mechanical vibration wave is emitted to the probe and the moment t2 when the liquid surface echo is received.

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

[0075]

[0076] Wherein, h is the liquid level height in the tank to be tested, 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 transmission speed of the mechanical vibration wave in the liquid in the tank to be tested, 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), q is the distance between the first characteristic 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 characteristic point Δ is the intersection of the central axis of the once reflected beam and the plane reflection surface of the deflector, the second characteristic point O is the intersection of the central axis of the once reflected beam and the parabolic reflection surface of the deflector, the once reflected beam is the beam of the main beam of the mechanical vibration wave reflected by the plane reflection surface, and the first preset point T is the intersection of the central axis of the main beam of the mechanical vibration wave and the inner wall of the tank to be tested when the central axis of the main beam passes through the tank to be tested.

[0077] The speed v at which the mechanical vibration wave is transmitted in the liquid in the tank to be tested can be obtained through calibration.

[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 in the tank to be tested and includes a reflective plane.

[0080] The calibration probe is also connected to the external level meter host. The calibration probe is used to transmit calibration mechanical vibration waves to the reflection plane outside the tank to be measured and receive calibration echoes (calibration echoes are calibration mechanical vibration waves reflected by the reflection plane).

[0081] The mechanical vibration waves emitted by the calibration probe may be ultrasonic waves, infrasonic waves, etc., which are mechanical vibration waves having the same emission parameters (eg, frequency, amplitude, etc.) as those of the aforementioned measuring probe.

[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 transmission speed v of the mechanical vibration wave in the liquid in the tank to be tested;

[0083] The central axis of the main beam of the calibration mechanical vibration wave is perpendicular to the reflection plane, so that the reflection plane vertically reflects the main beam and is 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 tested, the intersection of its central axis and the inner wall of the tank to be tested can be called the second preset point S1, and the distance from the second preset point S1 to the reflection plane can be used as the preset distance L mentioned above.

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

[0086] An exemplary structure of a calibrator is described below, including:

[0087] The support rod and the reflection plane can be installed in the tank to be tested through the support rod.

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

[0089] See also Fig.15 One end of the support rod is fixed to point B on the reflection 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 a point S2 on the plane reflection 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 the second line segment formed by point A and point B, or is parallel and equal (it can also be said that point S1, point S2, point A, and point B form 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 of 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 above description and will not be described in detail here.

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

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

[0097] For the parabolic reflector M2, its focus can be determined first, and the point on the transmission path of the first reflected beam that is at a distance p from the focus is determined as the installation point of the parabolic reflector M2 (which can be called the installation point C). Alternatively, the point on the transmission path of the first reflected beam that is at a distance pq from the point Δ is determined as the installation point C of the parabolic reflector M2. Where p is the focal length of the parabolic reflector M2, and q is the focal length of the aforementioned plane reflector M1.

[0098] The installation point C is made to coincide with the second characteristic point O of the parabolic reflective surface M2, the parabolic reflective surface M2 is made to face the primary reflected beam, and the line connecting the point Δ and the point C is made horizontal.

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

[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 emit 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 with 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 emits the mechanical vibration wave and the moment when the liquid surface echo is received.

[0104] The time when the probe emits 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 records and will not be repeated here.

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

[0106] Step E: Calculate the liquid level in the tank to be measured according to 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-mentioned embodiments, 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 can be selected as the measurement position T1 around the manhole flange near the vertical center line of the spherical tank at the bottom of the spherical tank, and the inclination angle β between the tangent plane of the tank outer wall and the horizontal plane can be measured according to the selected point. For details, please refer to the above-mentioned step S1, which will not be repeated here.

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

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

[0114] The third step is to determine the focal length q of the plane reflection surface, the first characteristic point Δ, and the focus T' of the parabola reflection surface. The specific determination method can be found in the above records and will not be repeated here.

[0115] Step 4: Establish coordinate system 2.

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

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

[0118] Please refer to the above-mentioned relevant records, which will not be elaborated here.

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

[0120] In the seventh step, the intersection point between the main beam edge ray and the plane reflection surface M1 is calculated according to the probe divergence angle 2θ0 as the first minimum edge position.

[0121] Step 8: Based on the first minimum edge position, a plane reflection plate M1 ′ including a plane reflection surface M1 is manufactured.

[0122] Step 9: Define p as the length of the straight line segment T'O, with p as the focal length. According to the parabola formula x' 2 =2py', input the value of x', get the parabola b of the T'X'Y' coordinate plane, take the coordinate axis T'Y' as the rotation axis, rotate the parabola b horizontally, and generate the target parabola B.

[0123] Step 10: design a parabolic reflective surface M2 according to the target parabola B, and manufacture a parabolic reflective plate M2' having the parabolic reflective surface M2.

[0124] Please refer to the above-mentioned relevant records, which will not be elaborated here.

[0125] Step 11: Make auxiliary parts.

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

[0127] Step 12: According to the designed installation position and installation angle, the plane reflector M1' and the parabolic reflector M2' are installed using the reflector bracket to form a full-energy double-reflection diverter for measuring the liquid level outside the spherical tank. The wave-proof mechanism is installed outside the diverter.

[0128] Step 13: Use the spherical tank full acoustic energy diverter to measure the liquid level of the spherical tank.

[0129] Please refer to the above record for how to obtain the liquid level, which will not be elaborated here.

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

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

[0132] like Figure 8 As shown, a right-handed rectangular three-dimensional coordinate system ΔX”Y”Z is established with point Δ as the coordinate origin, referred to as coordinate system 3 (as shown in Figure 8 As shown, Figure 8 (a) is the front view. Figure 8 (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 is also parallel to the horizontal coordinate axis TX of coordinate system 1, that is, ΔX” / / T'X' / / T1X. Coordinate axis ΔY”, coordinate axis ΔX”, and coordinate axis ΔZ” are perpendicular to each other. The ultrasonic incident line T1Δ is in the incident plane ΔT1X”, and the incident plane ΔTX” can rotate around the horizontal coordinate axis ΔX”. The angle between the incident plane ΔT1X” and the vertical coordinate plane ΔX”Y” of coordinate system 3 is the incident plane angle γ (as shown in Figure 2). Figure 8 As shown in (b) in the figure, the incident angle γ can be any angle. Assume that the incident plane ΔT1X” coincides with the vertical coordinate plane ΔX”Y” of the coordinate system 3 and the incident angle γ is 0 degrees, such as in the case of a spherical tank. The incident plane ΔT1X” coincides with the horizontal coordinate plane ΔX”Z” of the coordinate system 3 and the incident angle γ is 90°, which is the case of a vertical tank, such as Fig. 9 As shown, Fig. 9 (a) is the top view. Fig. 9 (b) is the front view. Fig. 9 (c) is the left view. It should be noted that when applied to a vertical tank, TZ and T'Z' in the above-mentioned coordinate system 1 and coordinate system 2 are vertically downward, TY is perpendicular to the TXZ plane and out of the paper, and T'Y' is perpendicular to the T'X'Z' plane and out of the paper.

[0133] In the solution of the present invention, the incident direction angle β of the ultrasonic wave emitted by the probe can be changed from -30° to 30°. The incident surface angle γ can be any angle, see Figure 8 (b) in . For example, Figure 2-Figure 3 The spherical tank shown is the case with an incident angle of γ = 0°. Fig. 9The vertical tank shown is the case of an incident angle γ = 90°. For a complex shaped container, the incident angle γ can be other angles, as long as the angle between the normal of the plane reflection surface M1 and the ultrasonic incident ray TΔ is equal to the angle between the normal and the ultrasonic outgoing ray ΔO of the plane reflection surface M1 and is equal to α / 2, it can be ensured that the central axis of the main ultrasonic beam emitted by the probe is reflected by the plane reflection surface M1 and then projected to the characteristic point O of the second parabolic reflection surface M2. Considering that the ultrasonic direction angle β emitted by the above-mentioned 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 reflection surface M1 and the ultrasonic incident ray TΔ is kept equal to the angle between the above-mentioned normal line and the ultrasonic outgoing ray ΔO of the plane reflection surface M1 and is equal to α / 2, it can be ensured that the central axis of the ultrasonic main beam emitted by the probe is reflected from the characteristic point Δ of the plane reflection surface M1 and then emitted to the characteristic point O of the second parabolic reflection surface M2. Therefore, the diverter method of the present invention is a "universal" steering method that can be widely applied to various complex structure containers such as spherical cans, vertical cans, sausage cans, etc. and can be flexibly applied.

[0134] It should be noted that in the above-mentioned solution, the measurement location (installation location) is selected first, and then the design and installation are carried out.

[0135] In other embodiments of the present application, other methods may also be used for design and installation. For example, because the target liquid level to be measured is horizontal, the horizontal placement state of the parabolic reflector M2 can be determined first, that is, the focal line T'O of the horizontally placed M2 can be determined first. Then, according to the focal length of the parabolic reflector M2 and the structure of the tank container, the installation position of the probe on the container is determined, and then, according to the structure of the tank container, the incident plane angle γ of the probe ultrasonic wave, the horizontal angle β of the probe ultrasonic wave incident, the distance q of the characteristic point Δ of the plane reflector M1 from the point T on the inner wall of the tank corresponding to the probe, and 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 horizontal angle 90°-α / 2 of M1 are determined.

[0136] In the application of the above embodiment, still taking the spherical tank as an example, when the liquid is filled from the bottom of the spherical tank, the liquid that violently flows into the tank causes the ultrasonic wave in the bottom liquid of the spherical tank to deviate from the original propagation direction along with the liquid flow, and the strong waves affect the liquid level measurement, and a large number of bubbles are generated to block the ultrasonic wave propagation. When the liquid is emptied, the external liquid level meter cannot receive the echo signal wave and interrupts the measurement. When the liquid is filled again, the external liquid level meter starts to search 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 echo reflected by the liquid surface is reflected back by the inner wall of the spherical tank near the probe, and is emitted again to the liquid surface and reflected back to the probe by the liquid surface, forming a phenomenon that multiple liquid surface echoes are obtained by emitting an ultrasonic signal once.

[0137] The embodiment of the present application can be provided with a wave-breaking mechanism to solve these problems. The wave-breaking mechanism can form a groove-shaped space (which can be called a wave-breaking groove) together with the inner wall of the tank to be tested; the diverter 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] A first ray is made along a first preset direction through any point on the plane reflecting surface, and the first ray intersects with the side wall of the wave-breaking mechanism; the first preset direction is: a horizontal direction away from the parabolic reflecting surface.

[0140] A second ray is made along a second preset direction through any point on the parabolic reflecting surface, and the second ray intersects with the side wall of the wave-breaking mechanism; the second preset direction is: a horizontal direction away from the plane reflecting surface.

[0141] Exemplarily, four flat plates are fixed to the periphery of the bracket around the plane reflector M'1 and the parabolic reflector M'2 to form a trapezoidal wave-breaking trough. The above four flat plates are an exemplary structure of the wave-breaking mechanism. The height of the parabolic reflector M'2 end of the wave-breaking trough is equal to the upper edge of M'2 (or higher than M'2), and the height of the plane reflector M'1 end of the wave-breaking trough is equal to the upper edge of M'1 (or higher than M'1), such as Fig.10 As shown, Fig.10 (a) is the front view of the installation of the wave-breaking trough. Fig.10 (b) is a right side view of the steering gear with a wave-breaking groove outside. Fig.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 liquid in the spherical tank is emptied, liquid will be stored in the wave-breaking trough. After the liquid level of the spherical tank drops to the port of the plane reflector of the wave-breaking trough, the liquid in the wave-breaking trough stops dropping rapidly when it continues to drop. During the period of time when the spherical tank is emptied, the external liquid level gauge device of the steering gear 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 the 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 generation of bubbles at the bottom of the tank are blocked by the wave-breaking trough, and do not enter between the plane reflector M'1 and the parabolic reflector M'2, and do not affect the normal measurement of the liquid level. There is an appropriate 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 groove drops more slowly than the liquid level outside the wave-breaking groove, and the liquid level in the wave-breaking groove rises again when the next liquid enters. The gap at the bottom of the wave-breaking groove also allows the sediment in the liquid in the wave-breaking groove to flow out of the wave-breaking groove.

[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 above-mentioned four side panels, as long as it can form a groove-shaped space and accommodate a steering gear and meet the above-mentioned 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 measuring position T1 of the tank body to be measured, and determine the horizontal inclination angle of the outer wall of the tank body to be measured at the measuring position T1 as the horizontal angle β of the exit end face of the mechanical vibration wave.

[0145] For example, the measuring position T1 (also called measuring point or installation position) of the probe can be selected around the manhole flange at the bottom of the spherical tank near the vertical center line of the spherical tank. The horizontal inclination angle β of the outer wall of the spherical tank is also the horizontal inclination angle of the working end face of the probe, and T1 is the center point of the working end face of the probe.

[0146] In 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 is a main beam and a group of weak side lobes in the far field. 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 into the spherical tank along the normal direction of the tangent plane of the tank inner wall is 2θ0, where θ0 is the half-divergence angle. The normal line of the tangent plane of the inner wall of the spherical tank at point T is the central axis of the main beam. The maximum sound pressure emitted by the probe in the direction of the central axis of the main beam is recorded as 100%. As the emission angle θ deviates from the direction of the central axis of the main beam, 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 chip is 45 mm, the resonant frequency f = 200 kHz, the speed of sound of water at 20°C is c = 1480 m / s, and the wavelength λ = c / f = 7.4 mm. It can be calculated that the half-divergence angle 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 reflection surface M1 in the diverter 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 the installation angle may be determined in the following manner: on the propagation path of the ultrasonic main beam, a point with 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 reflective surface M1. In addition, point Δ is the identification point of the plane reflective surface M1 obtained after the design is completed.

[0153] The installation angle of the plane reflection surface can be the angle between the plane reflection 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, α=90°-β.

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

[0155] In one example, for a spherical tank, see Figure 2-Figure 3 To facilitate understanding of the installation angle, the following is an explanation in conjunction with coordinate system 1; the coordinate axis TX of 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.

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

[0157] It should be noted that in actual applications, if the probe is installed at the center axis of the spherical tank and the right position of the manhole T1, then the right side of the spherical tank wall where the probe is installed is high and the left side is low. The characteristic point Δ of the plane reflection surface is at the upper left of T1, and the parabolic reflection surface is at the upper right of T1. Please refer to Figure 2 On the contrary, if you choose to install the probe at the center axis of the spherical tank and the left position of the manhole T1, then the left side of the spherical tank wall where the probe is installed is high and the right side is low. The characteristic point Δ of the plane reflection surface is at the upper right of T1, and the parabolic reflection surface is at the upper left of T1. Please refer to Figure 3 In short, the characteristic point Δ of the plane reflection surface is always in the direction of the center line 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 reflection surface M1 can be obtained by intercepting the plane according to certain requirements. This application will be further introduced later.

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

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

[0161] For example, see Figure 2 and Figure 3 , the point that is at a distance q from point Δ along the negative direction of the coordinate axis TX (the negative direction is opposite to the transmission path of the primary reflected beam) can be determined as point T'.

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

[0163] A point with a distance p from the focus along the target direction may be taken as the second feature point O. The target direction is the direction from the focus to the point Δ.

[0164] In fact, the above target direction is consistent with the transmission path of the once reflected beam.

[0165] For easier understanding, see Figure 2 and Figure 3, the coordinate axis T'X' of coordinate system 2 is parallel to the coordinate axis TX of coordinate system 1, that is, T'X' / / TX, and the same direction is horizontally to the right. The coordinate axis T'X', the coordinate axis T'Y', and the coordinate axis T'Z' are perpendicular to each other in the order of the right-handed three-dimensional coordinate system. Figure 2 and Figure 3 In the above, the positive direction is the target direction, which is consistent with the transmission path of the reflected beam once), and the point with a distance p from point T' is determined as the second feature point O.

[0166] S5: Determine the target parabola B according to the second feature point.

[0167] The target parabola B can be obtained as follows:

[0168] With point T' as the focus and distance p as the focal length, draw a parabola b through point O, such as Figure 6 shown.

[0169] The parabola b is horizontally rotated with the vertical coordinate axis T'Y' of the coordinate system 2 as the rotation axis (the axis is also the symmetry axis of the parabola b) to form a target parabola B.

[0170] Subsequently, a portion of the curved surface can be intercepted from the target parabola B as the parabola reflection surface M2. Of course, in some cases, the target parabola B may be directly used as the parabola reflection surface M2. The characteristic point O on the parabola b is the second characteristic point of the parabola reflection surface M2, the origin T' of the coordinate system 2 is the focus of the parabola reflection surface M2, and the focal length p of the parabola b is the focal length of the parabola reflection surface M2.

[0171] It can be seen that the ultrasonic rays of the ultrasonic main beam along the central axis are reflected by the plane reflection surface M1 and propagate a distance pq along the negative direction of the T'X' coordinate axis of coordinate system 2 to the characteristic point O of the parabolic reflection surface M2, and are reflected by the parabolic reflection surface and vertically upward along the direction of the T'Y' coordinate axis of coordinate system 2 toward the liquid surface, and 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 to the characteristic point O of the parabolic reflection surface M2 along the negative direction of the T'Y' coordinate axis of coordinate system 2, and after being reflected by the parabolic reflection surface M2, it is emitted toward the characteristic point Δ of the plane reflection surface M1, and after being reflected by the plane reflection surface M1, it is emitted toward the origin T of coordinate system 1 (i.e., the TXYZ coordinate system).

[0172] The following proves that the angle between the plane reflection surface M1 and the vertical coordinate axis TY is α / 2. Figure 7In the figure, draw an auxiliary line y through point Δ parallel to the coordinate axis TY, the auxiliary line s is perpendicular to the line segment TΔ, and the auxiliary line u is perpendicular to the plane reflection surface M1. The angle between the end face of the probe and the tangent plane on the outside of the spherical tank wall at the center point T1 of the probe end face and the parallel line of the coordinate axis TX through point T1 is β. Draw a perpendicular line to the spherical tank wall through point T1, and the intersection of the above perpendicular line and the inner wall of the spherical tank is point T. The extended line of the line segment T1T perpendicular to the spherical tank wall passes through point Δ. Because the straight line T1Δ is perpendicular to the tangent plane of the outer wall of the spherical tank through point T1, the angle between the straight line T1Δ and the auxiliary line y parallel to the coordinate axis TY is equal to β. Because the auxiliary line s is perpendicular to the straight line T1Δ, the angle between the auxiliary line s and the auxiliary line y is equal to 90°-β=α. Let the angle between the plane reflection surface M1 and the auxiliary line y be a, the angle between the plane reflection surface M1 and the auxiliary line s be c, and the 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 mark point Δ on the plane reflection surface M1 is equal to the exit angle, that is, the angle between the auxiliary line u and ΔX' is equal to the angle between the auxiliary line u and TΔ, which is equal to d, so the angle a+c=c+d=d+d=α, so the angle a=c=d=α / 2. Finally, it is concluded that the angle between the plane reflection surface M1 and the vertical coordinate axis TY is equal to α / 2.

[0173] Here's how to determine the dimensions of a flat reflector and a parabolic reflector:

[0174] When the detection intensity requirement is to fully reflect the main beam of the mechanical vibration wave, in an example, see Fig.13 , the intersection of the main beam edge ray and the target plane N can be calculated according to the divergence angle 2θ0 of the probe main beam, and the first minimum edge position D1 can be determined.

[0175] The target plane N is: a 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 reflective surface M1, and the first target area is determined by the first minimum edge position D1. Therefore, the first minimum edge position D1 is located at the edge of the plane reflective surface M1, or inside the plane reflective surface M1.

[0177] Accordingly, an exemplary parabolic reflector surface can be determined as follows:

[0178] The intersection position of the edge ray e of the primary reflected beam and the aforementioned target parabola B is determined as the second minimum edge position D2; according to the second minimum edge position D2, the size of the parabola reflective surface can be determined on the target parabola B. The second minimum edge position D2 is located at the edge of the parabola reflective surface, or inside the parabola reflective surface.

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

[0180] For example, in the case of full reflection, when the probe installation position T1 is on the right side of the center line of the spherical tank, see Figure 2 , the horizontal axis T'X' of coordinate system 2 can be used as the central axis to make a conical surface with an angle of 2θ0 along the positive direction of the horizontal axis T'X'. The intersection of this conical surface and the parabolic reflective surface M2 is the second minimum edge position D2 of the parabolic reflective 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 The second minimum edge position D2 of the parabola reflecting surface M2 can be determined by making a conical surface with an angle of 2θ0 along the negative direction of the horizontal coordinate axis T'X' with the horizontal coordinate axis T'X' as the central axis of the coordinate system 2.

[0181] In other embodiments of the present application, a conical surface of 2θ0 may be made, and the intersection line of the conical surface of 2θ0 and the parabola b (the intersection line includes part of the second minimum edge position D2 mentioned above) is used as the minimum parabola segment, and the minimum parabola segment is horizontally rotated with the vertical coordinate axis T'Y' of the coordinate system 2 as the rotation axis to form a parabola, and the obtained parabola is directly used as the parabola reflection surface M2, such as Fig.14 shown.

[0182] In other embodiments of the present application, a combined redirector using a partial reflective surface can be designed to reduce the volume, that is, by requiring partial reflection of the main beam of the mechanical vibration wave, such as Fig.11 As shown, the specific design method for determining the size of the plane reflective surface and the size of the parabolic reflective surface is:

[0183] The intersection position of the edge ray of the main beam of the mechanical vibration wave emitted at the measuring position and the target plane is determined 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: a plane made according to the installation position and installation angle; please refer to the above introduction for details, which will not be repeated here.

[0184] According to the ratio of partial reflection to total reflection, interception is performed in the first target area to obtain a planar reflection surface that meets the partial reflection requirement.

[0185] The design of the parabolic reflector surface can be found in the above description and will not be elaborated here.

[0186] After the design is completed, the above-mentioned diverter can be prepared.

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

[0188] Exemplarily, the 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 mounted on the bracket Z, and 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 reflection surface is in the direction of the center line of the spherical tank at the probe installation position T1. When T1 is on the right side of the center line of the spherical tank, the characteristic point Δ of the plane reflection surface is on the left side of T1. In coordinate system 2 (i.e., coordinate system T'X'Y'Z'), the angle between the plane reflection plate 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 center line of the spherical tank, the characteristic point Δ of the plane reflection surface is on the right side of T1. The angle between the plane reflection plate M'1 and the negative direction of the horizontal coordinate axis T'X' is 90°-α / 2, and the angle between the plane reflection plate M'1 and the vertical coordinate axis T'Y' is α / 2. The line connecting 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', and the length of the line ΔO connecting the identification point Δ of M'1 to the characteristic point O of the parabolic reflector M'2 is equal to Pq, 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 key point of the application of this application is that, because the liquid surface is horizontal, it is necessary to first determine the horizontal placement state of the second reflective curved surface M2, that is, first determine the focal line T'O of the horizontally placed M2. Then, determine the installation position of the probe on the container according to the focal length of the parabolic reflective surface M2 and the structure of the container, and then determine the incident plane angle γ and the incident horizontal angle β of the probe ultrasonic wave in turn according to the structure of the container, the distance q between the point T on the inner wall of the tank corresponding to the probe and the marking point Δ of the first reflective surface M1, and then determine the position of the marking 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 may be combined arbitrarily. To make the description concise, 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, they should be considered to be within the scope of this specification.

[0191] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A steering gear, characterized in that: The deflector comprises: a plane reflecting surface and a parabolic reflecting surface; The plane reflection surface is used to reflect the main beam of the mechanical vibration wave to form a primary reflection beam; The parabolic reflection 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, wherein the secondary reflected beam is a parallel beam, and the direction of the secondary reflected beam is vertically upward; The first preset point T coincides with the focus of the parabolic reflective surface at the mirror symmetry point of the plane reflective surface; the first preset point T is the intersection of the central axis of the main beam of the mechanical vibration wave and the inner wall of the tank to be tested when the main beam passes through the tank; The central axis of the once reflected beam is located on a horizontal plane; the central axis of the once reflected beam intersects with the plane reflecting surface at a first characteristic point Δ, and intersects with 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 angle between the plane reflection surface and the vertical direction is α / 2, wherein α+β=90°, and β is the horizontal angle of the exit end face of the main beam of the mechanical vibration wave.

3. The steering gear according to claim 1, characterized in that: The plane reflection surface is used to fully or partially reflect the main beam of the mechanical vibration wave, and the parabolic reflection surface is used to fully or partially reflect the primary reflection beam.

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

5. A liquid level measurement system, characterized in that: The liquid level measurement system comprises: a measuring probe and a diverter according to any one of claims 1 to 4; During measurement, the measuring probe is arranged outside the tank to be measured, and is used to emit mechanical vibration waves into the tank to be measured; wherein the main wave beam of the emitted mechanical vibration waves is the main wave beam of the mechanical vibration waves; The deflector is arranged in the tank to be tested, and the plane reflection surface of the deflector is located in the emission direction of the main wave beam of the mechanical vibration wave.

6. The liquid level measurement system according to claim 5, characterized in that: The liquid level measurement system further comprises: an external liquid level meter host; The external liquid level meter host is connected to the measuring probe; The external liquid level meter host is used to calculate the liquid level in the tank to be measured according to the time when the measuring probe transmits 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 tested is: Wherein, h is the liquid level height in the tank to be tested, 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 transmission speed of the mechanical vibration wave in the liquid in the tank to be tested, 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), q is the distance between the first characteristic 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 characteristic point Δ is the intersection of the central axis of the once reflected beam and the plane reflection surface of the deflector, the second characteristic point O is the intersection of the central axis of the once reflected beam and the parabolic reflection surface of the deflector, the once reflected beam is the beam of the main beam of the mechanical vibration wave reflected by the plane reflection surface, and the first preset point T is the intersection of the central axis of the main beam of the mechanical vibration wave and the inner wall of the tank to be tested when the central axis of the main beam passes through the tank to be tested.

8. The liquid level measurement system according to claim 6, characterized in that: The liquid level measurement system further comprises: a calibrator and a calibration probe; the calibrator comprises a reflection plane; The calibrator is located in the tank to be tested; The calibration probe is connected to the host of the external liquid level meter, and is used to transmit a calibration mechanical vibration wave to the reflection plane outside the tank to be measured, and receive a calibration echo; the calibration echo is a calibration mechanical vibration wave reflected by the reflection plane; The emission time of the calibration mechanical vibration wave, the reception time of the calibration echo and the preset distance L are used to calculate the transmission speed v of the mechanical vibration wave in the liquid in the tank to be tested; Wherein, the central axis of the main wave beam of the calibration mechanical vibration wave 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: when the main wave beam of the calibration mechanical vibration wave passes through the tank body, the intersection of its central axis and the inner wall of the tank body to be tested.

9. The liquid level measurement system according to claim 8, characterized in that: The reflecting plane is installed in the tank to be tested through a support rod; wherein one end of the support rod is fixed to a point A on the inner wall of the tank to be tested, and the other end is connected to the reflecting plane at a point B; The central axis of the main wave beam of the calibration mechanical vibration wave 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 the second line segment formed by point A and point B, or is parallel and equal; 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 to 9, characterized in that: The liquid level measurement system further comprises: a wave prevention mechanism; The wave-proof mechanism can form a groove-shaped space together with the inner wall of the tank to be tested; the diverter is arranged in the groove-shaped space; Wherein, a first ray is made 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-breaking mechanism; the first preset direction is: a horizontal direction away from the parabolic reflection surface; A second ray is made along a second preset direction through any point on the parabolic reflecting surface, and the second ray intersects with the side wall of the wave-breaking mechanism; the second preset direction is a horizontal direction away from the planar reflecting surface.

11. The liquid level measurement system according to claim 8 or 9, characterized in that: The external liquid level meter host is also used to calculate the transmission speed v of the mechanical vibration wave in the liquid in the tank to be measured using the following formula according to the preset distance L, the time t'1 when the calibration probe transmits the calibration mechanical vibration wave, and the time t'2 when the calibration mechanical vibration wave reflected by the reflection plane is received; v = 2L / (t'2 - t'1).

12. A liquid level measurement method, characterized in that: The liquid level measurement method uses the steering gear according to any one of claims 1 to 4, and the liquid level measurement method comprises: Set the measuring probe at the measuring position on the outer wall of the tank to be measured; A deflector is installed in the tank to be tested so that the plane reflection surface of the deflector is located in the emission direction of the measuring probe, and the parabolic reflection surface is located on the transmission path of the primary reflection beam, and the parabolic reflection surface can reflect the primary reflection beam to form a secondary reflection beam pointing vertically upward; wherein the primary reflection beam is obtained by the plane reflection surface reflecting the main beam of the mechanical vibration wave; and the emission direction is perpendicular to the tangent plane at the measurement position of the outer wall of the tank to be tested; The mechanical vibration wave is emitted to the tank body to be measured by using the measuring probe; the main wave beam of the emitted mechanical vibration wave is the main wave beam of the mechanical vibration wave; when the main wave beam of the mechanical vibration wave passes through the tank body to be measured, the intersection point of the central axis thereof with the outer wall of the tank body to be measured is the measuring position, and the intersection point with the inner wall of the tank body to be measured is the first preset point T; Record the moment when the measuring probe transmits the mechanical vibration wave and receives the liquid surface echo; The time when the measuring probe emits 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 measured.

13. The liquid level measurement method according to claim 12, characterized in that: Also includes: The liquid level in the tank to be measured is calculated based on the time when the measuring probe transmits the mechanical vibration wave and the time when the liquid surface echo is received.

14. A method for designing a steering device according to any one of claims 1 to 4, characterized in that: The design method comprises: Select a measurement position T1 of the tank body to be measured, and determine the horizontal inclination angle of the outer wall of the tank body to be measured at the measurement position T1 as the horizontal angle β of the exit end face of the mechanical vibration wave; The installation position and installation angle of the plane reflection surface are determined according to the horizontal angle β; the installation position of the plane reflection surface is located in the emission direction of the main wave beam of the mechanical vibration wave; the installation angle of the plane reflection surface is the angle between the plane reflection 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 reflection surface; According to the installation position and the installation angle, a mirror symmetric point T' of the first preset point T with respect to the plane reflection surface is determined as the focus of the parabola reflection surface; the first preset point T is the intersection point of the central axis of the main wave beam of the mechanical vibration wave and the inner wall of the tank body to be tested when the main wave beam passes through the tank body to be tested; wherein, the straight line passing through the mirror symmetric point T', the first characteristic point Δ and the second characteristic point O is a horizontal straight line; Determine a point with a distance p from the focus along a target direction as a second feature point O; the target direction is a direction from the focus to the first feature point Δ; Determine a target parabola according to the second feature point O and the focus; wherein a part of the curved surface on the target parabola is used as a parabola reflecting surface, or the target parabola is used as a parabola reflecting surface; According to the installation position, installation angle and detection intensity requirements, the size of the plane reflection surface is determined to obtain the plane reflection surface after the design is completed; The size of the parabola reflecting surface is determined according to the target parabola to obtain the designed parabola reflecting surface.

15. The design method of the steering gear according to claim 14, characterized in that: When the detection intensity requirement is to fully reflect the main wave beam of the mechanical vibration wave, the size of the plane reflection surface is determined according to the installation position, installation angle and detection intensity requirement, specifically including: The intersection position of the edge ray of the main beam of the mechanical vibration wave emitted at the measuring position and the target plane is determined 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: a plane made according to the installation position and the installation angle; The size of the planar reflective surface is determined on the target plane according to the first minimum edge position, so that any first minimum edge position is located at the edge of the planar reflective surface or inside the planar reflective surface.

16. The design method of the steering gear according to claim 14, characterized in that: When the detection intensity requirement is to partially reflect the main beam of the mechanical vibration wave, the size of the plane reflection surface is determined according to the installation position, installation angle and detection intensity requirement, specifically including: The intersection position of the edge ray of the main beam of the mechanical vibration wave emitted at the measuring position and the target plane is determined 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: a plane made according to the installation position and the installation angle; According to the ratio of partial reflection to total reflection, a plane reflection surface that meets the partial reflection requirement is intercepted from the first target area; wherein the ratio of the area of ​​the plane reflection surface to the first target area is consistent with the ratio; the first target area is an area determined on the target plane according to the first minimum edge position.

17. The design method of a steering gear according to any one of claims 14 to 16, characterized in that: Determine the intersection position of the edge ray of the primary reflected beam and the target parabola as the second minimum edge position; The size of the parabola reflecting surface is determined on the target parabola according to the second minimum edge position, so that any second minimum edge position is located at the edge of the parabola reflecting surface or inside the parabola reflecting surface.

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