A temperature effect correction method of a static level system

Abstract

The application discloses a temperature effect correction method of a hydrostatic level system, relates to the technical field of correction and calibration of the hydrostatic level system, and considers the shrinkage and expansion of the length direction and the radial direction of a connecting pipe between hydrostatic levels, the shrinkage and expansion of connecting liquid, and the shrinkage and expansion of a bowl body of the hydrostatic level, so that the influence of the temperature effect on data of the hydrostatic level can be reduced, and the temperature adaptability and precision of a hydrostatic level monitoring method can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of static leveling system correction calibration, and particularly relates to a temperature effect correction method for a static leveling system. BACKGROUND

[0002] A static leveling instrument is an automatic settlement monitoring device used to measure the relative height changes between two or more points, and is widely used in the vertical displacement monitoring of structures such as large storage tanks, dams, nuclear power plants, high-rise buildings, foundation pits, tunnels, bridges, and subways. A static leveling system usually consists of multiple static leveling instruments, and is based on the principle of a communicating vessel. The sensor containers are connected to each other through a connecting pipeline. In the connected containers, the liquid naturally seeks the same potential energy level. When settlement occurs at each observation point, it will cause changes in the liquid level height or pressure in each storage tank. The sensor of the static leveling instrument can sense the relative height changes of the liquid level in each test point storage tank, thereby calculating the differential settlement of each static leveling instrument relative to the reference point.

[0003] The common types of static leveling instruments on the market currently include differential transformer type, photoelectric type (CCD), magnetostrictive type, vibrating string type, capacitive type, ultrasonic type, and differential pressure type static leveling instruments. Except for the differential pressure type static leveling instrument, which determines the elevation of the measured point by measuring the pressure of the liquid surface on the deformation sensor, the other types of static leveling instruments mainly measure the liquid level height. In recent years, with the advancement of technology, static leveling measurement technology has developed rapidly. Reviewing the development history of static leveling instruments, the precision and stability mainly depend on the following aspects: sensor precision: the measurement precision of the static leveling instrument sensor itself. Data acquisition and correction method: effective data acquisition strategies and appropriate correction algorithms are crucial for improving the accuracy of measurement results. Temperature sensitivity and durability of system materials: the selection of materials for system components, including connecting liquids and connecting pipelines, will affect the long-term stability and reliability of the system. External environmental factors: such as temperature differences between different static leveling instruments, temperature gradient changes, tidal effects, and other external conditions that can affect measurement. Construction quality: factors such as the correct installation position and height of the static leveling instrument, and whether the air bubbles are completely discharged, will also affect the final measurement results. Among them, the temperature effect has a significant impact on the precision of the static leveling system. Temperature changes will cause the volume of the connecting liquid to expand or contract, the inner diameter of the connecting pipeline to change, and the inner diameter of the static leveling instrument bowl to change, which will all affect the liquid level height. Since the static leveling instrument is a precision measuring instrument, its measurement sensitivity is usually higher than 0.1 millimeters, so the temperature effect may significantly reduce the measurement precision of the method. Therefore, developing a reliable temperature effect correction method is one of the key technical challenges to improve the practicality of static leveling instruments. SUMMARY

[0004] Technical problems to be solved by the invention

[0005] The technical problem to be solved by the present application is to provide a temperature effect correction method for reducing the influence of temperature effect on data of a hydrostatic level, which can consider the influence of expansion in the length direction and the radial direction of a connecting pipe between hydrostatic levels, expansion of connecting liquid, and expansion of a hydrostatic level bowl on data.

[0006] Technical scheme

[0007] To solve the above problems, the technical scheme provided by the present application is as follows:

[0008] A temperature effect correction method for a hydrostatic level system, comprising the following steps:

[0009] S1, setting assumptions, assumption 1: ignoring the evaporation of connecting liquid in the monitoring process, assumption 2: the thermal expansion and contraction of connecting liquid does not affect the water pressure balance between hydrostatic levels, assumption 3: the absolute value of temperature gradient change is not greater than 2℃ / h, and the influence of temperature gradient on material thermal expansion is not considered, assumption 4: ignoring the expansion of the vertical direction of the hydrostatic level bowl, assumption 5: the temperature measured by the temperature sensor represents the temperature of the hydrostatic level bowl and the nearby connecting pipe;

[0010] S2, the hydrostatic level system has n hydrostatic levels, at t0, the readings of the hydrostatic levels are h1…hi…hj…hn, the installation heights are H1…Hi…Hj…Hn, the distances between hydrostatic level i and hydrostatic level j and the previous hydrostatic level are Li and Lj, respectively;

[0011] S3, calculating the volume change of connecting liquid, formula 1-1: ΔV=(1+α V,w )VΔT, in the formula, ΔV is the volume change amount of connecting liquid; α V,w is the volume expansion coefficient of connecting liquid; ΔT is the temperature change amount;

[0012] S4, calculating the size change of connecting pipe and hydrostatic level bowl, formula 1-2: ΔL=(1+α L )LΔT, in the formula, L and ΔL are size and size change amount; α L is the linear expansion coefficient of connecting pipe and hydrostatic level bowl, the linear expansion coefficient of connecting pipe is α L,P , and the linear expansion coefficient of hydrostatic level bowl is α L,B ;

[0013] S5、According to assumption 2, when the temperature changes, the communicating liquid between the static level i and the static level j will reach the water pressure balance at the midpoint M-M line. Examining the single static level i loop, the communicating liquid is divided into three parts according to the position, and the communicating liquid volume change includes the communicating pipe front pipe part V1i, the communicating pipe rear pipe part V2i and the static level bowl part V3i. Examining the ith static level, at t0, the inner diameter of the communicating pipe is The inner diameter of the static level bowl is The communicating pipe front pipe length is The communicating pipe rear pipe length is The static level bowl radius becomes The communicating pipe radius becomes The communicating pipe front pipe length is The communicating pipe rear pipe length is

[0014] S6, calculating the overflow of the communicating pipe front pipe part, formula 1-3:

[0015]

[0016] S7, calculating the overflow of the communicating pipe rear pipe, formula 1-4:

[0017]

[0018] S8, calculating the overflow of the static level bowl, formula 1-5:

[0019]

[0020] S9, calculating the static level i liquid level change under unit temperature change, formula 1-6: Similarly, Δhj is obtained. Let the static level i be the reference level, and the height be 0. Then the height of the static level j is hi-hj, and the temperature correction amount of the static level j is Δhi-Δhj.

[0021] As an option, in S2, if i=1, then L1=0.

[0022] As an option, the application condition of formula 1-1 is i≠1. When i=1, the overflow of the communicating pipe front pipe is 0.

[0023] As an option, the application condition of formula 1-2 is bowl i+1≤n, that is, the bowl i+1 cannot be the last bowl. When i+1>n, the overflow of the communicating pipe rear pipe is 0.

[0024] As an option, after supplementing the communicating liquid, the height of the communicating liquid changes, and the hi' of each static level is replaced by hi.

[0025] Alternatively, when the coefficient of thermal expansion of the material changes with temperature, α V and α L Replace it with a function for temperature.

[0026] Alternatively, the dimensions of the connecting pipe and the hydrostatic level can be varied by changing the inner diameter or length of the connecting pipe and the hydrostatic level.

[0027] Optionally, the temperature sensor of the hydrostatic level has an accuracy of 0.01 degrees Celsius or higher.

[0028] Beneficial effects

[0029] Compared with the prior art, the technical solution provided by this invention has the following advantages:

[0030] The technical solution provided by this invention considers the thermal expansion effects of the connecting pipe and the hydrostatic level's bowl, as well as the length of the connecting pipe between hydrostatic level instruments, to establish a temperature effect correction model suitable for complex scenarios. This model is intuitive and has significant scalability, facilitating further analysis and research. Applying this technical solution can reduce the impact of temperature effects on hydrostatic level data, and provides valuable insights for improving the temperature adaptability and accuracy of hydrostatic level monitoring methods. Attached Figure Description

[0031] Fig. 1 A schematic diagram of the structure of a hydrostatic leveling system proposed in an embodiment of the present invention;

[0032] Fig. 2 A schematic diagram of parameters for a temperature effect correction method for a hydrostatic leveling system proposed in an embodiment of the present invention;

[0033] Fig. 3 An embodiment of the present invention provides a method for correcting the temperature effect of a hydrostatic leveling system using three hydrostatic leveling instruments.

[0034] 1. First static level; 2. i-th static level; 3. j-th static level; 4. n-th static level; 5. Connecting pipe; 6. Bowl body; 7. Reference static level; 8. Second static level; 9. Third static level. Detailed Implementation

[0035] To further understand the content of this invention, a detailed description of the invention will be provided in conjunction with the accompanying drawings and embodiments.

[0036] Example 1

[0037] Combined with appendix Figs. 1-3 A method for correcting the temperature effect of a hydrostatic leveling system includes the following steps:

[0038] S1, set assumptions, assumption 1: ignore the evaporation of the connecting liquid in the monitoring process, assumption 2: the thermal expansion and contraction of the connecting liquid does not affect the water pressure balance between the static water levels, assumption 3: the absolute value of the temperature gradient change is not greater than 2℃ / h, and the influence of the temperature gradient on the thermal expansion of the material is not considered, assumption 4: the shrinkage and expansion of the static water level bowl in the vertical direction is ignored, assumption 5: the temperature measured by the temperature sensor represents the temperature of the static water level bowl and the nearby connecting pipe 5.

[0039] S2, the static water level system has n static water levels, the temperature sensor accuracy of the static water level is above 0.01 degrees Celsius, at time t0, the readings of the static water levels are h1…hi…hj…hn, the installation heights are H1…Hi…Hj…Hn, the distances between static water level i and static water level j and the previous static water level are Li and Lj respectively, if i=1, then L1=0. The n static water levels are: the first static water level 1, the i static water level 2, the j static water level 3 and the n static water level 4.

[0040] S3, calculate the volume change of the connecting liquid, formula 1-1: ΔV=(1+α V,w )VΔT, in the formula, ΔV is the volume change of the connecting liquid, α V,w is the volume expansion coefficient of the connecting liquid, and ΔT is the temperature change. The application condition of formula 1-1 is i≠1, when i=1, the overflow amount of the front pipe of the connecting pipe 5 is 0.

[0041] S4, calculate the size change of the connecting pipe 5 and the static water level bowl, formula 1-2: ΔL=(1+α L )LΔT, in the formula, L and ΔL are the size and size change, and the size change of the connecting pipe 5 and the static water level bowl is the change of the inner diameter or length of the connecting pipe 5 and the static water level. α L is the linear expansion coefficient of the connecting pipe 5 and the static water level bowl, the linear expansion coefficient of the connecting pipe 5 is α L,P , and the linear expansion coefficient of the static water level bowl is α L,B . The application condition of formula 1-2 is that the bowl i+1≤n, that is, the bowl i+1 cannot be the last bowl; when i+1>n, the overflow amount of the rear pipe of the connecting pipe 5 is 0. When the material expansion coefficient changes with temperature, replace α V and α L with the function of temperature.

[0042] S5、According to assumption 2, when the temperature changes, the communicating liquid between the ith static level 2 and the jth static level 3 will reach the water pressure balance at the midpoint M-M line. Regarding the circuit of the single ith static level 2, the communicating liquid is divided into three parts according to the position, and the communicating liquid volume change includes the front pipe part V1i of the communicating pipe 5, the rear pipe part V2i of the communicating pipe 5 and the static level bowl part V3i. Regarding the ith static level 2, at t0 moment, the inner diameter of the communicating pipe 5 is The inner diameter of the static level bowl is The front pipe length of the communicating pipe 5 is The rear pipe length of the communicating pipe 5 is The radius of the static level bowl becomes The radius of the communicating pipe 5 becomes The front pipe length of the communicating pipe 5 is The rear pipe length of the communicating pipe 5 is

[0043] S6, calculate the overflow of the front pipe part of the communicating pipe 5, formula 1-3:

[0044]

[0045] S7, calculate the overflow of the rear pipe of the communicating pipe 5, formula 1-4:

[0046]

[0047] S8, calculate the overflow of the static level bowl, formula 1-5:

[0048]

[0049] S9, calculate the liquid level change of the ith static level 2 under the unit temperature change, formula 1-6: Similarly, Δhj is obtained. Let the ith static level 2 be the reference level, and the height is 0. Then the height of the jth static level 3 is hi-hj, and the temperature correction amount of the jth static level 3 is Δhi-Δhj. After supplementing the communicating liquid, the height of the communicating liquid changes, and the hi' of each static level is replaced by hi.

[0050] When the temperature is 20℃, the inner diameter of the communicating pipe 5 is 4mm, and the outer diameter is 6mm. The bowl installation height H i are all 200mm. The horizontal distance L2 between the second static level 8 and the reference static level 7 is 20m, and the horizontal distance L1 between the third static level 9 and the second static level 8 is 20m.

[0051] The hydrostatic level's bowl is made of austenitic 304 stainless steel, and the connecting pipe 5 is made of silicone flexible tubing. At room temperature, the coefficient of thermal expansion of stainless steel is essentially constant, and the coefficient of thermal expansion of the silicone flexible tubing can be considered roughly constant. In this embodiment, the linear expansion coefficient of the bowl is taken as 1.7 × 10⁻⁶. -5 / K, the coefficient of linear expansion of connecting pipe 5 is taken as 5.9×10. -4 / K. If a material with a non-constant coefficient of thermal expansion is used, the linear expansion can be calculated using the integral method.

[0052] The connecting fluid is a mixture of GLYSANTIN antifreeze and water, diluted at a ratio of 1:3.

[0053] Under the conditions of the example, the ambient temperature was simulated to change. The temperature of the basin of the reference static level 7 slowly increased from 20°C to 30°C; the temperature of the basin of the second static level 8 slowly increased from 20°C to 28°C; and the temperature of the basin of the third static level 9 slowly increased from 20°C to 25°C. The actual elevation of the three static levels remained unchanged.

[0054] The expansion coefficient of a connecting fluid varies with temperature. Generally, the expansion coefficient of connecting fluids such as water changes significantly with temperature. Here, a mixture of GLYSANTIN antifreeze, known for its excellent thermal expansion properties, and water is selected, diluted at a ratio of 1:3. Within the temperature range of 20℃ to 30℃, when mixed at a dilution ratio of 1:3, the expansion coefficient formula is α = 3.8 × 10⁻⁶. -6 T+3.3×10 -5 Because the temperature variation range is relatively small, the volumetric expansion coefficient is considered constant during calculation. V,w The coefficient of thermal expansion at 25℃ is taken as 1.28 × 10⁻⁶. -4 / K. If a connecting fluid with a large variation in its expansion coefficient is used, the volume expansion can be calculated using the integral method.

[0055] 7-inch static level for inspection

[0056] The temperature at time t0 is 20℃, the same as during installation. The inner radius of connecting pipe 5... The inner radius of the hydrostatic level's bowl is 2mm. The liquid level in the bowl of the reference hydrostatic level 7 is 49.5 mm. It is 50mm. The length of the pipe before connecting pipe 5 is 0. The length of the pipe after connecting pipe 5 is... It is 10.2m.

[0057] t k At that moment, the temperature uniformly rose to 30℃. According to equation (1-2), the inner radius of the hydrostatic level's bowl was calculated. The inner radius of the connecting pipe 5 is 2.00118mm. It is 49.50084 mm.

[0058] i = 1, calculated according to formula (1-3), unit temperature change ΔV 11 is 0. calculated according to formula (1-4), unit temperature change ΔV 21 is -210.60mm 3 . calculated according to formula (1-5), unit temperature change ΔV 31 is -13.09mm 3 .

[0059] From t0 to t k , the temperature uniformly rises by 10℃, and Δh1 is -0.2905mm calculated according to formula (1-6).

[0060] The second static level 8

[0061] The temperature at t0 is 20℃, which is the same as when it is installed. At t k , the temperature uniformly rises to 28℃. According to the calculation method of the reference static level 7, ΔV 12 is -210.60mm 3 , ΔV 22 is -210.60mm 3 , ΔV 32 is 43.41mm 3 . Δh2 is -0.3926mm.

[0062] The third static level 9

[0063] The temperature at t0 is 20℃, which is the same as when it is installed. At t k , the temperature uniformly rises to 28℃. According to the calculation method of the reference static level 7, ΔV 13 is -210.60mm 3 , ΔV 23 is 0, ΔV 33 is -14.39mm 3 . Δh2 is -0.1461mm.

[0064] The temperature correction amount of the i static level is Δhi-Δhj, and finally the correction amount of the second static level 8 is 0.1020mm, and the correction amount of the third static level 9 is 0.1444mm.

[0065] Embodiment 2

[0066] Combined with the attached Fig. 3 , the temperature effect correction method of the static level system of this embodiment can be improved as follows compared with the technical solution of embodiment 1:

[0067] The horizontal spacing of the hydrostatic level is 10m, the installation height is 200mm, and the inner radius of the connecting pipe is 2mm.

[0068] Example 3

[0069] Combined with appendix Fig. 3 The temperature effect correction method for a hydrostatic leveling system in this embodiment can be improved as follows compared with the technical solutions of Embodiment 1 or 2:

[0070] The horizontal spacing of the hydrostatic level is 20m, the installation height is 300mm, and the inner radius of the connecting pipe is 2mm.

[0071] Example 4

[0072] Combined with appendix Fig. 3 The temperature effect correction method for a hydrostatic leveling system in this embodiment can be improved as follows compared with any of the technical solutions in embodiments 1-3:

[0073] The horizontal spacing of the hydrostatic level is 20m, the installation height is 200mm, and the inner radius of the connecting pipe is 2.5mm.

[0074]

[0075] In summary, as illustrated in Examples 1-4, the temperature effect correction method of the present invention is affected by the spacing of the hydrostatic level instruments, the installation height, and the inner radius of the connecting pipe. The correction method significantly improves the accuracy of the hydrostatic level instrument spacing and the inner radius of the connecting pipe by more than 0.1 mm.

[0076] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A method of correcting for temperature effects in a spirit level system, characterized in that, Comprise the following steps: S1, set the assumption, assumption 1: ignore the evaporation of the connecting liquid in the monitoring process, assumption 2: the thermal expansion and contraction of the connecting liquid does not affect the water pressure balance between the hydrostatic level, assumption 3: the absolute value of temperature gradient change is not greater than 2℃ / h, not considering the influence of temperature gradient on the thermal expansion of materials, assumption 4: ignore the shrinkage of the vertical direction of the hydrostatic level bowl, assumption 5: the temperature measured by the temperature sensor represents the temperature of the hydrostatic level bowl and the nearby connecting pipe; S2, the hydrostatic level system has n hydrostatic levels, at t0 time, the readings of the hydrostatic levels are h1…hi…hj…hn, the installation heights are H1…Hi…Hj…Hn, the distances between the hydrostatic level i and the hydrostatic level j and the previous hydrostatic level are Li, Lj respectively. S3, calculate the volume change of the connecting liquid, the application condition of formula 1-1 is i≠1, when i=1, the overflow of the connecting pipe is 0, formula 1-1: ΔV=(1+α V,w )VΔT, in the formula, ΔV is the volume change of the connecting liquid; α V,w is the volume expansion coefficient of the connecting liquid; and ΔT is the temperature change. S4, calculating the size change of the communicating pipe and the static level bowl, the application condition of formula 1-2 is that the bowl i+1≤n, that is, the bowl i+1 cannot be the last bowl; when i+1>n, the overflow of the communicating pipe is 0, formula 1-2: ΔL=(1+α L )LΔT, wherein, L and ΔL are the size and the size change amount; α L is the linear expansion coefficient of the communicating pipe and the static level bowl, the linear expansion coefficient of the communicating pipe is α L,P , and the linear expansion coefficient of the static level bowl is α L,B ; S5、According to assumption 2, when the temperature changes, the communicating liquid between the static level i and the static level j will reach the water pressure balance at the midpoint M-M line. Investigating a single static level i loop, the communicating liquid is divided into three parts according to the position, and the communicating liquid volume change includes the communicating pipe front pipe part V1i, the communicating pipe rear pipe part V2i and the static level bowl part V3i. Investigating the ith static level, at the time t0, the inner diameter of the communicating pipe is The inner diameter of the static level bowl is The communicating pipe front pipe length is The communicating pipe rear pipe length is The static level bowl radius becomes The communicating pipe radius becomes The communicating pipe front pipe length is The communicating pipe rear pipe length is S6, calculate the overflow of the front pipe part of the connecting pipe, formula 1-3: S7, calculate the overflow of the connecting pipe, formula 1-4: S8, calculate the overflow of the bowl of the static water level gauge, formula 1-5: S9, calculate the liquid level change of the static level under the unit temperature change, formula 1-6: Similarly, let static level i be the reference level and the elevation be 0, then the elevation of static level j is hi-hj, and the temperature correction of static level j is Δhi-Δhj.

2. The method for correcting temperature effect of a static level system according to claim 1, wherein, In the S2, if i=1, then L1=0.

3. The method for correcting temperature effect of a static level system according to claim 1, wherein, After supplementing the connecting liquid, the height of the connecting liquid changes, and the readings hi' of each hydrostatic level replace the readings hi.

4. The method for correcting temperature effect of a static level system according to claim 1, wherein, When the material expansion coefficient varies with temperature, replace a V and a L with a function of temperature.

5. The method for correcting temperature effect of a static level system according to any one of claims 1 to 4, characterized in that, The size change of the connecting pipe and the hydrostatic level bowl is the change of the inner diameter or length of the connecting pipe and the hydrostatic level.

6. The method for correcting temperature effect of a static level system according to any one of claims 1 to 4, characterized in that, The accuracy of the temperature sensor of the hydrostatic level is above 0.01 degrees Celsius.

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