A mass flowmeter measuring tube and a method for increasing the difference in fundamental frequencies of the measuring tube

Abstract

This application relates to the field of flow detection devices, and specifically discloses a mass flowmeter measuring tube and a method for increasing the difference in the fundamental frequencies of the measuring tube. It includes a tube body and strengthening members fixedly arranged on the outer wall of the tube body. There are two groups of the strengthening members and they are respectively located at both ends of the tube body. The overall structural length dimension in the cross-section of the tube body and the strengthening members is greater than the width dimension, so that the difference between the first fundamental frequency and the second fundamental frequency of the tube body is greater than 30 Hz. This application strengthens the local area of the tube body, improves the local stiffness of the tube body, realizes an increase in the difference between the first fundamental frequency and the second fundamental frequency while not causing a large change in the comprehensive performance, thereby achieving the comprehensive optimization of design, process and performance, and avoiding the defects of increased cost and extended cycle caused by increasing the difference in fundamental frequencies in the traditional method.

Description

Technical Field

[0001] The present application relates to the field of flow detection devices, and in particular, to a measuring tube of a Coriolis mass flowmeter and a method for increasing the difference in the fundamental frequencies of the measuring tube. Background Art

[0002] Mass flow refers to the mass of fluid passing through the effective cross-section of a closed pipe or an open trough per unit time, and the mass flow can be expressed as the product of the volume flow and the fluid density. A Coriolis mass flowmeter is an instrument for directly and precisely measuring the mass flow of a fluid. The Coriolis mass flowmeter includes one or more measuring tubes, a driver, and a sensor. Fluid can flow into the measuring tube; the driver is arranged on the measuring tube and is used to drive the measuring tube to vibrate; the sensor is arranged at the inlet and outlet of the measuring tube and is used to detect the vibration of the measuring tube.

[0003] When there is no relative motion between the measuring tube and the fluid, after the measuring tube is excited to vibrate, the vibrations at each point of the measuring tube itself are in the same phase. When there is relative motion between the measuring tube and the fluid, that is, when the fluid flows in the measuring tube, due to the inertial effect of the fluid, a Coriolis force proportional to the mass flow of the fluid will be generated on the pipe wall, causing differences in the responses of various parts of the measuring tube structure, and a phase difference will appear between the vibrations at the inlet and outlet of the measuring tube. The magnitude of the phase difference has a proportional relationship with the mass flow. Therefore, by detecting the phase difference at both ends of the measuring tube, the mass flow in the measuring tube can be obtained.

[0004] The frequency used to drive the measuring tube to vibrate is usually the first fundamental frequency of the measuring tube. When the first fundamental frequency and the second fundamental frequency of the measuring tube are relatively close, resonance is likely to occur when there is external interference or a change in the fluid flow condition, resulting in fluctuations and errors in the measurement signal, which seriously affects the performance of the Coriolis mass flowmeter. Therefore, how to effectively increase the difference in the fundamental frequencies of the measuring tube has become one of the key technical problems in improving the performance of the Coriolis mass flowmeter.

[0005] The traditional methods for increasing the difference in the fundamental frequencies generally include increasing the wall thickness, changing the material, and changing the configuration size. However, increasing the wall thickness will result in poor consistency in the bending process, a large number of auxiliary toolings, and the need to design special toolings for different wall thicknesses, seriously affecting cost control and the implementation cycle. Due to the characteristics of the internal flow medium, the pipeline material is generally selected from stainless steel materials with good corrosion resistance such as 304 and 316L. Expanding other material systems will bring engineering use risks. Changing the configuration size requires a systematic evaluation of the comprehensive performance, such as the influence of sudden temperature changes, unstable incoming flow, etc. on the structural stress and strain, resulting in an increase in the development cycle and the number of parameters to be evaluated. Therefore, the above traditional measures all increase the cost while changing the fundamental frequency and bring changes to the performance of the product system. Summary of the Invention

[0006] To avoid the defects of cost and cycle caused by increasing the fundamental frequency difference in traditional measuring tubes, the present application provides a measuring tube for a mass flowmeter and a method for increasing the fundamental frequency difference of the measuring tube.

[0007] In a first aspect, the present application provides a measuring tube for a mass flowmeter, adopting the following technical solution:

[0008] A measuring tube for a mass flowmeter includes a tube body and strengthening members fixedly arranged on the outer wall of the tube body. There are two groups of the strengthening members and they are respectively located at both ends of the tube body. The overall structural length dimension in the cross-section of the tube body and the strengthening members is greater than the width dimension, so that the difference between the first-order fundamental frequency and the second-order fundamental frequency of the tube body is greater than 30 Hz.

[0009] By adopting the above technical solution, local strengthening is carried out on a specific area of the tube body. While achieving an increase in the fundamental frequency difference, it does not cause a large change in the comprehensive performance, thus achieving the comprehensive optimization of design, process and performance; this method avoids the defects brought about by improving the fundamental frequency performance through methods such as wall thickness and material in the traditional method; since the difference between the first-order fundamental frequency and the second-order fundamental frequency is increased, when the frequency of the exciting force applied to the measuring tube is the first-order fundamental frequency of the measuring tube, the measuring tube will only perform first-order vibration and will not perform second-order vibration. Therefore, the resonance phenomenon generated when there is external interference or changes in the fluid flow condition is effectively avoided, thereby improving the stability and accuracy of the measurement signal and enhancing the overall performance of the mass flowmeter.

[0010] Optionally, the strengthening member includes two reinforcing sheets. The reinforcing sheets are arranged in a cuboid shape and are arranged along the length direction of the tube body. The two reinforcing sheets are located in the same plane and are symmetrically arranged on both sides of the tube body.

[0011] By adopting the above technical solution, after the reinforcing sheets are correctly installed in place, they can not only directly enhance the stiffness of the local area of the measuring tube and improve the anti-fluid impact ability of the measuring tube, but also form additional mass damping to further suppress the occurrence of low-frequency vibration; under high-frequency vibration conditions, due to their relatively large weight and geometric structure, the reinforcing sheets can effectively weaken the vibration intensity transmitted to the sensor, thereby improving the stability of the entire system.

[0012] Optionally, a spacing ring is fixedly arranged on the outer wall of the tube body on one side of the reinforcing sheet, and the spacing ring abuts against the end of the reinforcing sheet.

[0013] By adopting the above technical solution, the spacing ring can play a limiting role, making the ends of the two reinforcing sheets at the same end of the tube body flush. Therefore, it helps to improve the installation accuracy and thus ensure the influence on the fundamental frequency of the measuring tube; the setting of the spacing ring can also increase the stiffness of the corresponding position of the tube body and enhance the ability of the tube body to resist external vibration, thereby ensuring the accuracy of the measurement.

[0014] Optionally, the reinforcing member includes an arc-shaped plate and a connecting plate. There are two arc-shaped plates, which are symmetrically distributed on both sides of the pipe body. There are two connecting plates, which are symmetrically distributed on both sides of the pipe body. The inner sides of the arc-shaped plate and the connecting plate are both in contact with the outer wall of the pipe body. The connecting plate is arranged between the two arc-shaped plates, and the connecting plate and the arc-shaped plate are integrally formed.

[0015] By adopting the above technical solution, the stiffness of the pipe body in two directions can be improved. The stiffness increased in one direction is more than that in the other direction. Therefore, the symmetry of the pipe body can be weakened, and the fundamental frequency difference of the measuring pipe can be increased. Since the connecting plate and the arc-shaped plate are integrally formed, the reinforcing member becomes a whole, and the installation of the reinforcing member is more convenient, which helps to ensure the installation accuracy.

[0016] Optionally, the reinforcing member includes two arc-shaped pieces. The two arc-shaped pieces are symmetrically arranged on both sides of the pipe body, and the sides of the two arc-shaped pieces close to each other are in contact with the outer wall of the pipe body.

[0017] By adopting the above technical solution, the stiffness of the pipe body in one direction can be improved, and the fundamental frequency difference of the measuring pipe can be increased.

[0018] Optionally, the reinforcing member includes two reinforcing rods. The two reinforcing rods are symmetrically arranged on both sides of the pipe body. The reinforcing rod includes a first connecting rod and a second connecting rod. The first connecting rod is arranged along the radial direction of the pipe body, the second connecting rod is arranged along the axial direction of the pipe body, there are two first connecting rods, and the second connecting rod is fixedly connected between the two first connecting rods.

[0019] By adopting the above technical solution, the stiffness of the pipe body in one direction can be improved, and the fundamental frequency difference of the measuring pipe can be increased.

[0020] Optionally, the reinforcing member includes a connecting ring and a connecting piece. The connecting ring is sleeved on the outer wall of the pipe body, the connecting piece is fixedly connected to the outer wall of the connecting ring, and there are two connecting pieces, which are symmetrically arranged on both sides of the connecting ring.

[0021] By adopting the above technical solution, the stiffness of the pipe body in two directions can be improved. The stiffness increased in one direction is more than that in the other direction. Therefore, the symmetry of the pipe body can be weakened, and the fundamental frequency difference of the measuring pipe can be increased. Since both connecting pieces are fixed on the connecting ring, the reinforcing member can form a whole, so the installation process of the reinforcing member can be made more convenient.

[0022] Optionally, the reinforcing member is made of stainless steel.

[0023] By adopting the above technical solution, it is possible to ensure that the reinforcing member has good corrosion resistance and mechanical strength, extend the service life, and also avoid the defect of inconsistent coefficient of thermal expansion caused by temperature changes.

[0024] Optionally, the shape of the pipe body is one of a straight pipe type, a U shape, and a door shape.

[0025] By adopting the above technical solution, the reinforcing member can be applied to various forms of pipe bodies, so the applicability is stronger.

[0026] In a second aspect, the present application provides a method for increasing the fundamental frequency difference of a measurement pipe, adopting the following technical solution:

[0027] A method for increasing the fundamental frequency difference of a measurement pipe, based on the measurement pipe of any one of the above mass flow meters, the method for increasing the fundamental frequency difference of the measurement pipe includes the following steps:

[0028] a. Determine the structural parameters of the pipe body, and the structural parameters include the length, diameter, wall thickness, material of the pipe body, and the connection method with other components;

[0029] b. Based on the structural parameters of the pipe body, use finite element analysis software to establish a mechanical model of the pipe body;

[0030] c. Perform modal analysis on the established mechanical model to calculate the first-order fundamental frequency and the second-order fundamental frequency of the pipe body;

[0031] d. According to the calculated first-order fundamental frequency and second-order fundamental frequency, determine whether the difference between the two is greater than 30 Hz. If the difference is greater than 30 Hz, it indicates that the current pipe body structure already meets the frequency requirements and no further optimization is required; if the difference is less than or equal to 30 Hz, proceed to the next step;

[0032] e. Set a reinforcing member at the boundary of the pipe body. The characteristic parameters of the reinforcing member include length, width, height, and the installation position relative to the pipe body. The adjustment strategy for the characteristic parameters of the reinforcing member includes but is not limited to the following several types:

[0033] Change the length and width dimensions of the reinforcing member;

[0034] Change the height dimension of the reinforcing member;

[0035] Change the installation position of the reinforcing member relative to the pipe body;

[0036] f. After each adjustment of the characteristic parameters, re-use the finite element analysis software to perform modal analysis on the modified mechanical model of the pipe body, calculate the new first-order fundamental frequency and second-order fundamental frequency, and again determine whether the difference between the two is greater than 30 Hz; repeat steps e and f until the difference between the first-order fundamental frequency and the second-order fundamental frequency is greater than 30 Hz;

[0037] g. Perform phase difference simulation calculations according to the determined structural parameters;

[0038] h. Manufacture the measuring tube of the mass flowmeter according to the finally determined structural parameters of the tube body that meet the frequency requirements.

[0039] By adopting the above technical solution, it is possible to effectively increase the difference between the first-order fundamental frequency and the second-order fundamental frequency of the measuring tube of the mass flowmeter, avoid resonance phenomena when there are external interferences or changes in fluid flow conditions, thereby reducing the fluctuations and errors of the measurement signal, and improving the performance of the mass flowmeter.

[0040] In summary, the present application includes the following beneficial technical effects:

[0041] 1. Locally strengthen specific areas of the tube body. While achieving an increase in the fundamental frequency difference, it does not cause a large change in the comprehensive performance, thereby achieving the comprehensive optimization of design, process, and performance, and avoiding the defects of increased cost and extended cycle brought about by increasing the fundamental frequency difference in the traditional method.

[0042] 2. The setting of the spacer ring helps to improve the installation accuracy of the reinforcing sheet, thereby ensuring the symmetry of the reinforcing sheet, helping to ensure the reinforcement effect on the stiffness of the tube body, and thus better increasing the difference between the first-order fundamental frequency and the second-order fundamental frequency of the measuring tube. Description of the Drawings

[0043] Figure 1 is the finite element analysis diagram of the first-order fundamental frequency and the second-order fundamental frequency used in Embodiment 1 of the present application;

[0044] Figure 2 is the overall structural schematic diagram of Embodiment 1 of the present application;

[0045] Figure 3 is the overall structural schematic diagram of Embodiment 2 of the present application;

[0046] Figure 4 is the structural schematic diagram of the reinforcing member in Embodiment 2 of the present application;

[0047] Figure 5 is the overall structural schematic diagram of Embodiment 3 of the present application;

[0048] Figure 6 is the overall structural schematic diagram of Embodiment 4 of the present application;

[0049] Figure 7 is the overall structural schematic diagram of Embodiment 5 of the present application.

[0050] Reference Numerals: 1, tube body; 2, reinforcing sheet; 3, spacer ring; 4, arc plate; 5, connecting plate; 6, arc piece; 7, reinforcing rod; 71, first connecting rod; 72, second connecting rod; 8, connecting ring; 9, connecting piece. Detailed implementation mode

[0051] The following will Figure 1 - Figure 7 further illustrate the present application in detail. Embodiment

[0052] The embodiment of the present application discloses a measuring tube of a mass flowmeter. Referring to Figure 1 and Figure 2 , the measuring tube of the mass flowmeter includes a tube body 1 and a reinforcing member. In this embodiment, the tube body 1 is arranged in a straight tube shape; in other embodiments, the tube body 1 can also be arranged in a U shape or a door shape. Both the reinforcing member and the tube body 1 are made of stainless steel, so while ensuring corrosion resistance, the defect of inconsistent thermal expansion coefficients caused by temperature changes can be avoided. The reinforcing member is fixedly connected to the outer wall of the tube body 1, and there are two groups of reinforcing members which are respectively located at both ends of the tube body 1.

[0053] The reinforcing member includes two reinforcing sheets 2. The reinforcing sheet 2 is a thin sheet structure in the shape of a cuboid, and the thickness of the reinforcing sheet 2 is 2 mm; the reinforcing sheet 2 is fixedly welded to the outer wall of the tube body 1. The reinforcing sheet 2 is arranged along the length direction of the tube body 1, and the two reinforcing sheets 2 are located in the same plane and symmetrically arranged on both sides of the outside of the tube body 1. Therefore, the setting of the reinforcing sheet 2 can increase the stiffness of the tube body 1 in one direction, while the stiffness of the tube body 1 in the other direction remains unchanged, so as to adjust the natural frequency of the measuring tube, thereby increasing the difference between the first-order fundamental frequency and the second-order fundamental frequency of the measuring tube.

[0054] In other embodiments, the reinforcing sheet 2 can be thickened, and one side of the thickened reinforcing sheet 2 can be set as an arc surface that can abut against the outer wall of the tube body 1, so that the reinforcing sheet 2 can better fit the outer wall of the tube body 1 and enhance the connection effect.

[0055] Furthermore, a distance ring 3 is also fixedly connected to the outer wall of the tube body 1. There are two distance rings 3 which respectively correspond to the two groups of reinforcing members; the two distance rings 3 are respectively located on the sides of the two groups of reinforcing members away from each other. The distance ring 3 is a circular ring, and the inner diameter of the distance ring 3 is the same as the outer diameter of the tube body 1. The distance ring 3 is fixedly welded to the outer wall of the tube body 1. One side of the distance ring 3 abuts against the ends of the two reinforcing sheets 2, and the distance ring 3 and the reinforcing sheet 2 are fixedly welded together. Therefore, the setting of the distance ring 3 can position the installation of the reinforcing sheet 2, thereby improving the installation accuracy of the reinforcing sheet 2.

[0056] The implementation principle of Embodiment 1 is as follows: The fixed-distance rings 3 are welded and fixed to the outer wall of the pipe body 1, and the two fixed-distance rings 3 are arranged at intervals. Then, the two reinforcing sheets 2 are respectively placed on both sides of the pipe body 1, and one end of the reinforcing sheet 2 is abutted against the fixed-distance ring 3. Then, the reinforcing sheet 2 is welded and fixed to the outer wall of the pipe body 1 and between the reinforcing sheet 2 and the fixed-distance ring 3, thus completing the production of the measuring pipe. Then, detection coils for detecting vibration can be arranged at both ends of the measuring pipe, a magnet is arranged on the outer wall in the middle of the measuring pipe, and a driving coil is arranged outside the magnet. When the driving coil is energized, the measuring pipe can be made to vibrate, and the vibration frequency of the measuring pipe is its first-order fundamental frequency; then, the phase difference of the vibration at both ends of the measuring pipe is detected by the detection coil, and the detection of the mass flow rate in the measuring pipe can be completed.

[0057] Since the measuring pipe is provided with a reinforcing member, the difference between the first-order fundamental frequency and the second-order fundamental frequency of the measuring pipe is increased. Therefore, when the frequency of the vibration applied to the measuring pipe by the driving coil is the first-order fundamental frequency of the measuring pipe, the measuring pipe will only vibrate at the first-order fundamental frequency and is not likely to vibrate at the second-order fundamental frequency, thus avoiding the adverse effect on the measurement caused by the superposition phenomenon when the two vibrations occur simultaneously. Therefore, the detection accuracy can be improved.

[0058] This embodiment also discloses a method for increasing the difference between the fundamental frequencies of the measuring pipe, including the following steps:

[0059] Step a. Determine the structural parameters of the pipe body 1, and the structural parameters include the length, diameter, wall thickness, material of the pipe body 1, and the connection method with other components.

[0060] Step b. Based on the structural parameters of the pipe body 1, establish a mechanical model of the pipe body 1 using finite element analysis software.

[0061] Step c. Perform modal analysis on the established mechanical model to calculate the first-order fundamental frequency and the second-order fundamental frequency of the pipe body 1.

[0062] Step d. According to the calculated first-order fundamental frequency and second-order fundamental frequency, judge whether the difference between the two is greater than 30 Hz. If the difference is greater than 30 Hz, it indicates that the current structure of the pipe body 1 already meets the frequency requirements and no further optimization is required; if the difference is less than or equal to 30 Hz, proceed to the next step.

[0063] Step e. Set a reinforcing member at the boundary of the pipe body 1. The characteristic parameters of the reinforcing member include length, width, height, and the installation position relative to the pipe body 1. The adjustment strategies for the characteristic parameters of the reinforcing member include but are not limited to the following:

[0064] (1) Change the length and width dimensions of the reinforcing member.

[0065] (2)Change the height dimension of the reinforcement. Through reasonable adjustment, the torsional resistance of the pipe body 1 in a certain direction can be improved, thereby increasing the difference between the first-order fundamental frequency and the second-order fundamental frequency of the pipe body 1.

[0066] (3)Change the installation position of the reinforcement relative to the pipe body 1. Different spatial layout differences will cause changes in the fundamental frequency of the pipeline vibration. For example, arranging in the vibration mode sensitive area can effectively increase the difference between the fundamental frequencies of each order, and this method can also effectively improve the ability of the product to resist fluid impact.

[0067] Step f. After each adjustment of the characteristic parameters, re-use the finite element analysis software to perform modal analysis on the modified mechanical model of the pipe body 1, calculate the new first-order fundamental frequency and second-order fundamental frequency, and determine again whether the difference between the two is greater than 30 Hz; repeat Step e and Step f until the difference between the first-order fundamental frequency and the second-order fundamental frequency is greater than 30 Hz.

[0068] Step g. Perform a phase difference simulation calculation according to the determined structural parameters.

[0069] Step h. Manufacture the measuring pipe of the mass flowmeter according to the finally determined structural parameters of the pipe body 1 that meet the frequency requirements.

[0070] Among them, Figure 1 The above two figures in show the finite element analysis diagrams when the reinforcement sheet 2 is not provided on the pipe body 1. The left figure shows that the first-order fundamental frequency is 1337.5 Hz, and the right figure shows that the second-order fundamental frequency is 1337.8 Hz. It can be seen that the difference between the two is 0.3 Hz. Figure 1 The following two figures in show the finite element analysis diagrams after the reinforcement sheet 2 is provided on the pipe body 1. The left figure shows that the first-order fundamental frequency is 1341.5 Hz, and the right figure shows that the second-order fundamental frequency is 1687 Hz. It can be seen that the difference between the two is 345.5 Hz. Therefore, setting the reinforcement sheet 2 can increase the difference between the first-order fundamental frequency and the second-order fundamental frequency of the measuring pipe, thereby avoiding vibration superposition and helping to improve the measurement accuracy. Embodiment

[0071] Referring to Figure 3 and Figure 4 , the difference between this embodiment and Embodiment 1 is that the reinforcement in this embodiment includes an arc-shaped plate 4 and a connecting plate 5. There are two arc-shaped plates 4, which are symmetrically arranged on two sides of the pipe body 1, and there are two connecting plates 5, which are symmetrically arranged on the other two sides of the pipe body 1. Both connecting plates 5 are located between the two arc-shaped plates 4; the connecting plate 5 and the arc-shaped plate 4 are of an integral structure. The mutually approaching sides of the two arc-shaped plates 4 and the mutually approaching sides of the two connecting plates 5 are both set as arc surfaces that can abut against the outer wall of the pipe body 1, and the arc-shaped plate 4 and the connecting plate 5 are both welded to the outer wall of the pipe body 1. Embodiment

[0072] Referring toFigure 5 , the difference between this embodiment and Embodiment 1 is that the reinforcing member in this embodiment includes two arc-shaped pieces 6. The two arc-shaped pieces 6 are symmetrically arranged on both sides of the tube body 1, and the arc-shaped pieces 6 are welded to the outer wall of the tube body 1; the inner diameter of the arc-shaped piece 6 is the same as the outer diameter of the tube body 1, so the inner wall of the arc-shaped piece 6 fits against the outer wall of the tube body 1. Embodiment

[0073] Refer to Figure 6 , the difference between this embodiment and Embodiment 1 is that the reinforcing member in this embodiment includes two reinforcing rods 7. The two reinforcing rods 7 are in the same plane and are symmetrically arranged on both sides of the tube body 1. The reinforcing rod 7 includes a first connecting rod 71 and a second connecting rod 72. The first connecting rod 71 is arranged along the radial direction of the tube body 1, and the end of the first connecting rod 71 is welded to the outer wall of the tube body 1. The second connecting rod 72 is arranged along the axial direction of the tube body 1. There are two first connecting rods 71 arranged at intervals, and the second connecting rod 72 is welded between the two first connecting rods 71. The second connecting rod 72 is arranged at an interval from the outer wall of the tube body 1. Embodiment

[0074] Refer to Figure 7 , the difference between this embodiment and Embodiment 1 is that the reinforcing member in this embodiment includes a connecting ring 8 and a connecting piece 9. The connecting ring 8 is a circular ring, and the inner diameter of the connecting ring 8 is the same as the outer diameter of the tube body 1. The connecting ring 8 is welded and fixed on the outer wall of the tube body 1. The connecting piece 9 is arranged in a cuboid shape, and the connecting piece 9 is welded and fixed to the outer wall of the connecting ring 8; there are two connecting pieces 9, and the two connecting pieces 9 are in the same plane and are symmetrically arranged on both sides of the connecting ring 8.

[0075] The above are the optional embodiments of the present application, and do not limit the protection scope of the present application accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of the present application should be covered within the protection scope of the present application.

Claims

1. A method for increasing the fundamental frequency difference of a measuring tube, characterized in that: The following steps are involved: a. clarifying the structural parameters of the tube body (1), wherein the structural parameters include the length, diameter, wall thickness, material of the tube body (1) and the connection method with other components; b. Based on the structural parameters of the pipe body (1), a mechanical model of the pipe body (1) is established using finite element analysis software; c. Performing modal analysis on the established mechanical model to calculate the first-order fundamental frequency and the second-order fundamental frequency of the tube body (1); d. Based on the calculated first-order fundamental frequency and second-order fundamental frequency, determine whether the difference between the two is greater than 30 Hz. If the difference is greater than 30 Hz, it indicates that the current tube body (1) structure has met the frequency requirement and no further optimization is required. If the difference is less than or equal to 30 Hz, proceed to the next step. e. A reinforcement member is provided at the boundary of the tube body (1). The characteristic parameters of the reinforcement member include length, width, height and installation position relative to the tube body (1). The characteristic parameter adjustment strategies of the reinforcement member include but are not limited to the following: Change the length and width of the reinforcement; Changing the height dimension of the reinforcement; Changing the installation position of the reinforcement member relative to the pipe body (1); f. After each adjustment of the characteristic parameters, re-use the finite element analysis software to perform modal analysis on the modified mechanical model of the tube body (1), calculate new first-order fundamental frequency and second-order fundamental frequency, and again determine whether the difference between the two is greater than 30 Hz; repeat step e and step f until the difference between the first-order fundamental frequency and the second-order fundamental frequency is greater than 30 Hz; g. Perform phase difference simulation calculation based on the determined structural parameters; h. manufacturing a measuring tube of the mass flow meter according to the finally determined structural parameters of the tube body (1) that meet the frequency requirements; The measuring tube comprises a tube body (1) and a reinforcement member fixedly arranged on the outer wall of the tube body (1), wherein the reinforcement member is arranged in two groups and is respectively located at two ends of the tube body (1), and the length dimension of the overall structure in the cross section of the tube body (1) and the reinforcement member is greater than the width dimension, so that the difference between the first-order fundamental frequency and the second-order fundamental frequency of the tube body (1) is greater than 30 Hz.

2. A method for increasing the fundamental frequency difference of a measuring tube according to claim 1, characterized in that: The reinforcing member comprises two reinforcing sheets (2), the reinforcing sheets (2) being arranged in a rectangular parallelepiped shape, the reinforcing sheets (2) being arranged along the length direction of the tube body (1), the two reinforcing sheets (2) being located in the same plane and symmetrically arranged on both sides of the tube body (1).

3. A method for increasing the fundamental frequency difference of a measuring tube according to claim 2, characterized in that: A distance ring (3) is fixedly arranged on the outer wall of the tube body (1) at one side of the reinforcing sheet (2), and the distance ring (3) abuts against the end of the reinforcing sheet (2).

4. The method for increasing the fundamental frequency difference of a measuring tube according to claim 1, characterized in that: The reinforcing member comprises an arc-shaped plate (4) and a connecting plate (5); two arc-shaped plates (4) are provided and are symmetrically distributed on both sides of the tube body (1); two connecting plates (5) are provided and are symmetrically distributed on both sides of the tube body (1); the inner sides of the arc-shaped plate (4) and the connecting plate (5) are both in contact with the outer wall of the tube body (1); the connecting plate (5) is provided between the two arc-shaped plates (4); and the connecting plate (5) and the arc-shaped plate (4) are provided in an integrated manner.

5. The method for increasing the fundamental frequency difference of a measuring tube according to claim 1, characterized in that: The reinforcing member comprises two arc-shaped pieces (6), the two arc-shaped pieces (6) are symmetrically arranged on two sides of the tube body (1), and the sides of the two arc-shaped pieces (6) close to each other are in contact with the outer wall of the tube body (1).

6. The method for increasing the fundamental frequency difference of a measuring tube according to claim 1, characterized in that: The reinforcement member comprises two reinforcement rods (7), the two reinforcement rods (7) are symmetrically arranged on both sides of the tube body (1), the reinforcement rod (7) comprises a first connecting rod (71) and a second connecting rod (72), the first connecting rod (71) is arranged along the radial direction of the tube body (1), the second connecting rod (72) is arranged along the axial direction of the tube body (1), two first connecting rods (71) are provided, and the second connecting rod (72) is fixedly connected between the two first connecting rods (71).

7. The method for increasing the fundamental frequency difference of a measuring tube according to claim 1, characterized in that: The reinforcement member comprises a connecting ring (8) and a connecting plate (9); the connecting ring (8) is sleeved on the outer wall of the tube body (1); the connecting plate (9) is fixedly connected to the outer wall of the connecting ring (8); two connecting plates (9) are provided and are symmetrically arranged on both sides of the connecting ring (8).

8. The method for increasing the fundamental frequency difference of a measuring tube according to claim 1, characterized in that: The reinforcement is made of stainless steel.

9. The method for increasing the fundamental frequency difference of a measuring tube according to claim 1, characterized in that: The shape of the tube body (1) is one of a straight tube type, a U-type, and a gate type.

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