Liquid level metering method of liquid level instrument

Abstract

The invention relates to a liquid level metering method of a liquid level meter, which comprises the following steps: receiving pressure data detected by a first pressure sensor and a second pressure sensor, and judging the position of an oil liquid level; calculating the inclination angle of the probe according to the pressure data; the distance between the first pressure sensors is corrected according to the calculated inclination angle, and the actual height is obtained; the liquid density between the first pressure sensors is calculated according to the received pressure data and the actual height, and the position of an oil-water interface is judged according to the calculated liquid density; according to the liquid density and pressure data, the distance between the first pressure sensor and the oil liquid level is calculated, and the height of the oil liquid level is obtained; the sum of the pressure intensity of the water and the pressure intensity of the oil is the detection result of the first pressure sensor at the tail end of the detection rod, the sum of the water layer height and the oil layer height is the liquid level height, the water layer height and the oil layer height are obtained, and the oil volume is obtained by comparing the tank capacity meter of the oil storage tank. The metering method is accurate in metering, high in precision and high in reliability.

Description

Technical Field

[0001] This invention relates to the field of oil metering, and particularly to a liquid level metering method. Background Technology

[0002] Gas stations primarily handle the receipt, sale, and storage of fuel, all of which require quantitative measurement of the fuel in storage tanks for effective fuel management. While routine inventory management focuses on the amount of fuel received, stored, and remaining in each tank, measuring the quantity of bulk liquid fuel like petroleum cannot be done by simply counting, nor is weighing convenient in a gas station setting. The most common method is to measure the liquid volume—that is, by measuring the amount of fuel occupied in the storage tank. Currently, level gauges are typically used for this purpose. A level gauge consists of a probe installed on the storage tank and a control panel located in the gas station office. By detecting the height of the fuel level in the tank, the volume occupied by the fuel can be determined.

[0003] Current probes primarily utilize magnetostrictive technology, which involves a float on the probe. The float's movement in response to changes in the liquid level determines the oil level, allowing for the calculation of the oil volume. However, oil storage tanks may tilt during use, causing the probe to shift and introducing errors in the oil measurement method, thus affecting the accuracy of oil detection. Summary of the Invention

[0004] To address the technical problems existing in the prior art, this invention proposes a liquid level measurement method for a liquid level gauge, comprising: receiving pressure data detected by a first pressure sensor at different heights on a probe and a second pressure sensor disposed on an inclination detection plane, and determining the location of the oil surface based on the received pressure data; calculating the inclination angle of the probe based on the pressure data detected by the second pressure sensor; correcting the distance between the first pressure sensors at different heights based on the calculated inclination angle to obtain the actual height of the first pressure sensors in the vertical direction; and calculating the liquid level between the first pressure sensors based on the received pressure data detected by the first pressure sensors and the actual height of the first pressure sensors in the disposal direction. The system calculates the liquid density and determines the location of the oil-water interface based on the calculated liquid density. Using the liquid density between the first pressure sensors and the pressure data detected by the first pressure sensors, it calculates the distance between the first pressure sensors and the oil surface using the liquid pressure formula. The height of the oil surface is obtained by summing the distance between the first pressure sensors and the oil surface with the actual height of the first sensor on the probe. A system of equations is formed by combining the formulas for calculating the sum of water pressure and oil pressure as the result of the first pressure sensor's detection at the end of the probe and the formulas for calculating the sum of water layer height and oil layer height as the liquid surface height. Solving the system of equations yields the water layer height and the oil layer height, and comparing this with the tank capacity table of the oil storage tank yields the volume of the oil.

[0005] As described above, the liquid level measurement method compares the pressure data from the first pressure sensor at different heights on the probe with 0 to determine the position of the oil level.

[0006] As described above, in the liquid level measurement method, when the pressure data comparison results of two adjacent first pressure sensors are different, it is determined that the oil level is located between the two adjacent first pressure sensors.

[0007] The liquid level measurement method described above further includes: confirming that the tilt angle measuring plane is above or below the oil surface.

[0008] As described above, the liquid level measurement method compares the pressure data detected by the second pressure sensor with 0. When the pressure data is greater than 0, the tilt angle measuring plane is below the oil surface; when the pressure data is less than or equal to 0, the tilt angle measuring plane is below the oil.

[0009] As described above, when the tilt measurement plane is above the oil level, a low level alarm is triggered, prompting the operator to take subsequent actions according to the low level situation.

[0010] The liquid level measurement method described above compares the pressure data from multiple second pressure sensors. When the pressure data are the same, it is confirmed that the probe is in a vertical state; when the pressure data are different, it is confirmed that the probe is in a tilted state.

[0011] The liquid level measurement method described above calculates the probe tilt angle based on the shape of the second pressure sensor and its projection onto the horizontal plane, combined with the liquid pressure formula and spatial structure relationship.

[0012] The liquid level measurement method described above determines whether the liquid composition has changed by judging whether the liquid density between each first pressure sensor is the same. When the first liquid density is different from the adjacent second and third liquid densities, it is determined that the oil-water interface is located between the first pressure sensors corresponding to the first liquid density.

[0013] The liquid level measurement method described above further includes: storing the second liquid density and the third liquid density as oil density and water density, respectively; comparing and verifying the second liquid density with the corresponding standard density of the stored oil; issuing an alarm message when the error value of the comparison and verification exceeds the allowable range, prompting the operator to check the equipment or verify the oil quality; and replacing the second density with the standard density for storage when the error value of the comparison and verification does not exceed the allowable range.

[0014] The metering method of this application calculates the probe tilt angle using a second pressure sensor and can correct the calculation process, thereby accurately determining the volume of the oil, making the oil metering more accurate, precise, and reliable. Attached Figure Description

[0015] The preferred embodiments of the present invention will now be described in further detail with reference to the accompanying drawings, wherein:

[0016] Figure 1 This is a schematic diagram of a level gauge probe according to one embodiment of this application;

[0017] Figure 2 An exploded view of a level gauge probe according to an embodiment of this application;

[0018] Figure 3A and Figure 3B This is a schematic diagram of a level gauge probe structure according to an embodiment of this application;

[0019] Figures 4A-4C A diagram illustrating a probe application scenario according to an embodiment of this application; and

[0020] Figure 5 This is a flowchart of a liquid level metering process according to one embodiment of the present application. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In the following detailed description, reference can be made to the accompanying drawings, which form part of this application and illustrate specific embodiments of the present application. In the drawings, similar reference numerals describe substantially similar components in different figures. Specific embodiments of the present application are described in sufficient detail below to enable those skilled in the art to implement the technical solutions of the present application. It should be understood that other embodiments may also be utilized, or structural, logical, or electrical changes may be made to the embodiments of the present application.

[0023] This application proposes a novel measurement method. It utilizes a first pressure sensor on a probe to detect pressure at different heights within the oil storage tank, and calculates the oil height using the detected pressure. Furthermore, a second pressure sensor calculates the tank's tilt angle to correct for the oil height, thus yielding the precise oil volume. This measurement method eliminates the need for moving parts during detection, is unaffected by the detection environment, and provides a more accurate calculated oil height. Even in cases of unclear oil-water interfaces, the theoretical interface position can still be calculated, improving the accuracy and precision of oil measurement and demonstrating high reliability.

[0024] The technical solution of this application will be further illustrated below through specific implementation methods. Those skilled in the art should understand that the following description is merely for the convenience of understanding the technical solution of this application and should not be used to limit the scope of protection of this application.

[0025] Figure 1 This is a schematic diagram of a level gauge probe according to one embodiment of this application. Figure 2 An exploded view of a level gauge probe according to one embodiment of this application. Figure 3A and Figure 3B This is a schematic diagram of a level gauge probe structure according to an embodiment of this application.

[0026] As shown in the figure, the level gauge probe (hereinafter referred to as "probe") 100 may include a mounting ring 110 and a probe rod 120. The mounting ring 110 is used to mount the probe onto the oil storage tank. The probe rod 120 is connected to the mounting ring and extends into the oil storage tank to detect data in the tank. In some embodiments, the data may include oil level, water level, liquid density, liquid pressure, temperature, etc. In some embodiments, the probe rod 120 may also be connected to a control console, and the data detected by the probe rod 120 can be transmitted to the control console.

[0027] In some embodiments, the mounting ring 110 may be a rubber ring with a generally V-shaped cross-section. When the probe is installed at the installation port of the oil storage tank, the rubber ring compresses the probe rod 120 to fix it inside the installation pipe, while also sealing the probe rod to the installation port. In some embodiments, the mounting ring 110 may also be other structures that allow the probe rod to be mounted on the oil storage tank.

[0028] In some embodiments, the probe 120 may include a probe body 121 and an electronic head 122. The electronic head 122 may include a protruding stepped structure that can be engaged in a mounting ring, providing support and positioning for the probe. The probe body 121 may be connected to the electronic head and extend into the oil storage tank. In some embodiments, the probe 120 may further include a plurality of first pressure sensors 123 and a temperature sensor 124. The plurality of first pressure sensors 123 are arranged at different heights on the probe body 121 to measure the pressure at different heights; the temperature sensor 124 is disposed on the probe body 121 to measure the temperature (liquid temperature or gas phase temperature) inside the oil storage tank. In some embodiments, the probe 120 may further include a plurality of second pressure sensors 125, which may be disposed on the same horizontal plane of the probe body 121. The detection results of the plurality of second pressure sensors can determine whether the probe body is in a vertical state and can also determine the tilt angle of the probe body.

[0029] In some embodiments, the electronic head 122 may further include circuit elements and may be connected to a first pressure sensor, a second pressure sensor, and a temperature sensor to receive sensor detection data. In some embodiments, the electronic head 122 may also be connected to the control console of the level gauge. For example, it may be directly connected to the control console via a communication cable, thereby uploading the sensor detection data to the control console, which can then calculate data such as liquid density, oil level, and water level based on the detection data.

[0030] In some embodiments, the probe body 121 may include a connecting section 1211 and a probe section 1212. A first pressure sensor, a second pressure sensor, and a temperature sensor may be disposed on the probe section 1212. The connecting section 1211 connects the probe section 1211 and the electronic head 122, increasing the length of the probe and connecting the sensors to the electronic head. In some embodiments, the connecting section 1211 may be a flexible probe, through which an oil communication cable may be threaded for communication connection between the sensors and the electronic head. In some embodiments, the flexible probe may be a metal corrugated pipe, a steel wire reinforced rubber tube, etc. In some embodiments, the probe section 1212 may be a rigid probe to support the sensors.

[0031] In some embodiments, the probe body 121 may further include a base 1213, which may be disposed at the end of the probe segment 1212 away from the connecting segment, and can fix the probe segment to the bottom of the oil storage tank. A first pressure sensor is arranged on the probe segment along its axial direction; a second pressure sensor may be arranged on a plane perpendicular to the axis of the probe segment. In some embodiments, the second pressure sensors are disposed on the same plane, which is located between the distribution of the first pressure sensors. In some embodiments, the first pressure sensors may be evenly spaced on the probe segment. In some embodiments, the first pressure sensors may be arranged from a position near the base towards the connecting segment. In some embodiments, the base 1213 may be a magnetic base, which can adsorb the rigid probe segment to the bottom of the oil storage tank. In some embodiments, the diameter of the base 1213 is larger than the diameter of the probe segment, which is beneficial for supporting the probe segment.

[0032] Figures 4A-4C This is a diagram illustrating a probe application scenario according to an embodiment of this application. As shown, the probe 100 can be installed on the oil storage tank 10 and extended into the oil storage tank. It can be used to measure the pressure and temperature inside the oil storage tank, and can upload the measured data to the control console 20 to calculate the volume of oil in the oil storage tank.

[0033] refer to Figure 4B According to one embodiment of this application, five first pressure sensors are arranged near the end of the probe, and are designated as O1, O2, O3, O4, and O5 from bottom to top; the pressure values ​​measured by each first pressure sensor are respectively denoted by P. o1 P o2 P o3 P o4 P o5 The distance between two adjacent pressure sensors on the probe is represented by H. 12 H 23 H 34 H 45This indicates that when the probe is installed inside the oil storage tank, the detection section may have an angle, and the actual vertical height between each first pressure sensor differs from its distance on the probe. The actual height is expressed as: The probe is also equipped with three second pressure sensors for measuring the tilt angle, located on the same horizontal plane (also known as the "tilt angle detection plane") between the first pressure sensor O4 and the first pressure sensor O5, and designated as H1, H2, and H3 respectively; the pressure values ​​measured by each second pressure sensor are denoted by P. H1 P h2 P h3 This is indicated. The theoretical distance H between the tilt detection plane where the second pressure sensor is located and the first pressure sensor O1 is also indicated. h The actual height difference between the second pressure sensor and the first pressure sensor O1 is H. H1 H H2 H h3 .

[0034] This application calculates the oil volume using the assumption that the oil level is between O4 and O5 and the water level is between O2 and O3 as an example. The specific detection and calculation process is as follows:

[0035] First, the approximate position of the oil level is determined by the pressure values ​​measured by the first pressure sensor and the second pressure sensor. Based on P... o5 =0, P H1 p H2 P H3 If the value is greater than 0, it can be determined that the oil level is below 0.5 and above the tilt angle detection plane. In some embodiments, when the oil level is below the tilt angle measurement plane or below any of the second pressure sensors in the tilt angle measurement plane, a low level alarm is triggered, prompting the replenishment of oil into the storage tank.

[0036] Secondly, the angle θ′ between the tilt measurement plane and the theoretical horizontal plane is calculated using the detection results of the second pressure sensor, thus obtaining the tilt angle θ=θ′ of the flexible probe probe section.

[0037] refer to Figure 4C The calculation process for the inclination angle θ of the flexible probe's detection section is as follows:

[0038] like Figure 4C As shown, the three second pressure sensors at locations H1, H2, and H3 form a known triangle H1H2H3 during the manufacturing of the probe section of the flexible probe. The lengths of the three sides and the three interior angles are determined during manufacturing, and the manufacturing process ensures that the tilt angle measuring plane of the triangle formed by the second pressure sensors is perpendicular to the axis of the probe section. When the probe section is tilted, the dihedral angle θ′ formed by the tilt angle measuring plane and the horizontal plane is the tilt angle θ of the probe section axis.

[0039] When the tilt measurement plane is tilted, the lowest point of the second pressure sensor in the vertical direction is H1, and the highest point is H3. The projection of ΔH1H2H3 onto the horizontal plane is ΔABC, where A, B, and C are the projection points of H1, H2, and H3 onto the horizontal plane, respectively. Point A coincides with H1. Extend line segments H2H3 and CB to intersect at point D. Connect AD, and draw perpendicular lines from H3 and C to AD, with the feet of these perpendiculars coinciding at point E. ∠H3EC is the dihedral angle θ between the tilt measurement plane and the horizontal plane. In some embodiments, when the tilt measurement plane includes more than three second pressure sensors, different triangles can be formed using different second pressure sensors to verify the calculation results, further improving the calculation accuracy.

[0040] From the liquid pressure formula and the above spatial structure relationship, we can see that:

[0041]

[0042] H3D = H2D + H2H3 (Equation a2)

[0043] The lengths of H2D and H3D can be obtained from equations (a1) and (a2).

[0044] By |P H3 -P H1 |=ρ 油 gH3C, from which can be derived

[0045] Furthermore, given H3D, H1H3, and ∠H1H3H2, the length of H1D can be determined using the Law of Cosines.

[0046] From the formula for the area of ​​a triangle: The length of H3E can be calculated:

[0047]

[0048] Depend on Angle θ can be calculated.

[0049] Secondly, by correcting the distance between the first pressure sensors on the probe based on the calculated inclination angle θ of the detection section, the actual vertical height between each first pressure sensor can be obtained.

[0050] The formula for calculating the actual height is as follows: m and n represent the serial numbers of the first pressure sensors, for example, the distance between O2 and O3 is expressed in H. 23 express.

[0051] Secondly, by using the pressure values ​​measured by the first pressure sensor and the calculated actual height, and by calculating the liquid density between each of the first pressure sensors using the density calculation formula, ρ can be obtained. 12 ρ 23 ρ 34 ρ 45 By comparing the obtained liquid densities, ρ can be obtained. 12 >ρ 23 ρ 23 >ρ 34 Therefore, it can be determined that the oil-water interface is located between O2 and O3. Furthermore, the oil density can be calculated as ρ. 34 The density of water is ρ 12 The oil density can be compared with the standard density of the corresponding stored oil for verification. In some embodiments, if the oil-water separation interface is located elsewhere, the oil density and / or water density can also be calculated using density calculation formulas.

[0052] The density calculation formula is as follows: Where, ρ mn This represents the density results between each of the first pressure sensors; m and n represent the serial numbers of each first pressure sensor, for example, the liquid density between O2 and O3 is expressed in terms of ρ. 23 This indicates that the liquid densities between O2 and O5 are expressed in terms of ρ. 25 express.

[0053] Secondly, the vertical distance between the pressure sensor and the liquid surface is calculated using the density data and the pressure measurement results from the first pressure sensor O3 or the first pressure sensor O4. And based on the vertical distance between the first pressure sensor O3 or the first pressure sensor O4 and the liquid surface Add the actual vertical height of the first pressure sensor O3 or the first pressure sensor O4 The liquid level height H can be obtained. o .

[0054] The formula for calculating the vertical distance between the first pressure sensor and the liquid surface is as follows: Where, ρ g The density of the oil is ρ, which can be related to the density of the oil. 油 The same can also be calculated.

[0055] The formula for calculating the density of the oil is as follows:

[0056]

[0057] Finally, the oil height H is calculated using the pressure calculation formula and the liquid level calculation formula. g and water height Hw Based on the calculation results, by comparing them with the tank capacity table, data such as the total volume of liquid, water volume, and oil volume inside the tank can be obtained.

[0058] The formula for calculating liquid level is: H g +H w =H o

[0059] The formula for calculating pressure is: ρ g gH g +ρ w gH w =P 01

[0060] Where, ρ w This is the density of water.

[0061] When the probe of this application is installed on an oil storage tank: the probe section and the base are placed into the oil storage tank through the installation port. The base is attached to the bottom of the tank, and the electronic head is secured in the installation port by a rubber ring. The electronic head is connected to the control console through a communication cable. The flexible section contains only the communication cable and can be kept in a slack state, which helps to reduce the complexity of the installation process, facilitates product standardization and inventory management, and only requires the production of a few probes of specific lengths to meet the needs of oil storage tanks of different heights. It also facilitates the transportation and storage of the flexible probe.

[0062] The probe of this application calculates the oil volume based on the detection results from multiple pressure measurement points. The probe requires no moving parts during the detection process, is not affected by the detection environment, and therefore has high reliability and accurate calculation results. Furthermore, multiple pressure measurement points allow for verification and validation during density measurement and calculation, effectively reducing measurement errors and improving the reliability of the probe. A pressure sensor can also be used to detect whether the probe section is tilted, and the calculation results can be corrected to obtain an accurate oil volume. The probe is not affected by tilting forces caused by installation issues or tank tilting, which could affect measurement accuracy. In addition, even when the oil-water interface is unclear, the probe of this application can accurately calculate the location of the theoretical interface.

[0063] This application also proposes a liquid level measurement method for a liquid level gauge.

[0064] Figure 5 This is a flowchart of a liquid level metering process according to one embodiment of the present application.

[0065] As shown in the figure, in step 510, pressure data detected by the first pressure sensor and the second pressure sensor are received, and the approximate position of the oil level is determined based on the pressure data. In some embodiments, the pressure data from the first pressure sensors from top to bottom are sequentially compared with 0 to determine the position of the oil level. In some embodiments, the approximate position of the oil level can be determined when the comparison results of two adjacent first pressure sensors are different. For example, if the pressure value of the first first pressure sensor is equal to 0 and the pressure value of the second first pressure sensor is greater than 0, it can be determined that the oil level is located between the first and second first pressure sensors.

[0066] In some embodiments, it can also be confirmed that the plane (or tilt measurement plane) where the second pressure sensor is located is above or below the oil surface. In some embodiments, the pressure data detected by the second pressure sensor is compared with 0. When the pressure data of the second pressure sensor is greater than 0, the tilt measurement plane is below the oil surface; when the pressure data of the second pressure sensor is less than or equal to 0, the tilt measurement plane is above the oil surface. In some embodiments, when the tilt measurement plane is above the oil surface, a low liquid level alarm is triggered, prompting the operator to take subsequent actions according to the low liquid level situation. In some embodiments, subsequent actions include, but are not limited to: notifying the upstream oil depot to replenish oil and stopping the oil tank from discharging oil.

[0067] In step 520, the probe's tilt angle θ is calculated based on the pressure data from the second sensors. In some embodiments, the pressure data from multiple second pressure sensors are compared with each other. When the pressure data from multiple second pressure sensors are the same, it is confirmed that the probe is in a vertical state, and the probe's tilt angle θ is 0°. When the pressure data from multiple second pressure sensors are different, it is confirmed that the probe is in a tilted state, and the probe's tilt angle θ is calculated. In some embodiments, the angle θ' between the tilt angle measurement plane and the theoretical horizontal plane can be calculated using the pressure data from the second pressure sensors, thereby obtaining the probe's tilt angle θ = θ'. In some embodiments, multiple second pressure sensors can form a triangle. Using the projection of this triangle onto the horizontal plane, combined with the liquid pressure formula and spatial structure relationships, the probe's tilt angle θ can be calculated.

[0068] In some embodiments, the probe may also be provided with multiple tilt angle measurement planes, and multiple sets of tilt angles can be calculated for mutual verification to improve the accuracy of measurement and calculation. In some embodiments, multiple second pressure sensors may also be provided in the tilt angle measurement planes of the probe, and the accuracy of measurement and calculation can be improved by mutual verification through the combination of different second pressure sensors.

[0069] In step 530, the distance between each first pressure sensor is corrected using the calculated tilt angle, thereby obtaining the actual height of each first pressure sensor in the vertical direction. In some embodiments, trigonometric functions are used to correct the distance between the first pressure sensors.

[0070] In step 540, the liquid density between each of the first pressure sensors is calculated based on the pressure data detected by the first pressure sensors and the corrected actual height, and the oil-water interface is determined based on the calculated liquid density. In some embodiments, the liquid density between each of the first pressure sensors is calculated using a liquid pressure calculation formula. In some embodiments, the liquid composition can be determined by whether the liquid densities between each of the first pressure sensors are the same. For example, when the liquid density between the first group of first pressure sensors is a first density; the liquid density between the second group of first pressure sensors is a second density; and the liquid density between the third group of first pressure sensors is a third density, wherein the second density is greater than the third density and the third density is greater than the first density, it can be determined that the liquid between the first group of first pressure sensors is oil, the liquid between the second group of first pressure sensors is water, and the liquid between the third group of first pressure sensors is an oil-water interface. In some embodiments, the grouping of the first pressure sensors can be two adjacent first pressure sensors or multiple pressure sensors spaced apart.

[0071] In some embodiments, a first density may be stored as the standard density for oil, and a second density may be stored as the standard density for water. In some embodiments, the first density may be compared and verified with the corresponding standard oil density stored on the control panel. If the error value of the comparison verification exceeds the allowable range, an alarm message is issued, prompting the operator to check the equipment or verify the oil quality. If the error value of the comparison verification does not exceed the allowable range, the first density is replaced with the standard density. In some embodiments, the alarm message may be an audible alert, a visual alert, a text alert, etc.

[0072] In step 550, the vertical distance between the first pressure sensor and the oil surface is calculated using the liquid density between each first pressure sensor and the pressure data detected by the first pressure sensor. In some embodiments, the vertical distance between the first pressure sensor and the oil surface is also calculated using the liquid pressure calculation formula. In some embodiments, the calculation needs to be performed using a first pressure sensor below the oil surface. In some embodiments, the height of the oil surface can be determined based on the vertical distance between the first pressure sensor and the oil surface and the actual height of the first pressure sensor. For example, the oil surface height can be obtained by summing the actual height of the first pressure sensor from the end of the probe rod and the vertical distance between the first pressure sensor and the liquid surface.

[0073] In step 560, the water layer height and oil layer height can be obtained by solving the liquid pressure calculation formula and the liquid level height calculation formula. Comparing these with the tank capacity table of the oil storage tank, data such as the liquid volume, water volume, and oil volume inside the tank can be obtained. In some embodiments, the liquid pressure calculation formula can be the sum of the water pressure and the oil pressure, which is the pressure detection result of the first pressure sensor at the end of the probe. The liquid level height calculation formula can be the sum of the water layer height and the oil layer height, which is the liquid level height.

[0074] The liquid level measurement method of this application accurately calculates the volume of oil by utilizing the detection results of pressure sensors at different heights. It can also calculate the inclination angle of the probe and correct the distance between the pressure sensors, thereby making the oil measurement more accurate, precise, and reliable. It can be applied to more complex working conditions and will not be affected by installation or tank tilting issues.

[0075] The above embodiments are for illustrative purposes only and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the scope of the invention. Therefore, all equivalent technical solutions should also fall within the scope of the invention.

Claims

1. A liquid level measurement method for a liquid level gauge, comprising: The system receives pressure data from a first pressure sensor at different heights on the probe and a second pressure sensor located on the tilt detection plane, and determines the location of the oil level based on the received pressure data. The probe's tilt angle is calculated based on the pressure data detected by the second pressure sensor; The distance between the first pressure sensors at different heights is corrected based on the calculated tilt angle to obtain the actual height of the first pressure sensor in the vertical direction. The liquid density between the first pressure sensors is calculated based on the pressure data detected by the first pressure sensor and the actual height of the first pressure sensor in the treatment direction, and the position of the oil-water interface is determined based on the calculated liquid density. The distance between the first pressure sensor and the oil surface is calculated using the liquid density between the first pressure sensors and the pressure data detected by the first pressure sensors, and the liquid pressure formula is used. The height of the oil level is obtained by summing the distance between the first pressure sensor and the oil surface with the actual height of the first sensor on the probe; and The formulas for calculating the sum of water pressure and oil pressure as the detection result of the first pressure sensor at the end of the probe rod, and the formula for calculating the sum of water layer height and oil layer height as the liquid level height, are used to form a set of equations. Solving the set of equations yields the water layer height and oil layer height, and comparing them with the tank capacity table of the oil storage tank yields the volume of the oil.

2. According to the liquid level measurement method of claim 1, the pressure data of the first pressure sensor at different heights on the probe are compared with 0 in sequence to determine the position of the oil level.

3. According to the liquid level measurement method of claim 2, when the pressure data comparison results of two adjacent first pressure sensors are different, it is determined that the oil level is located between the two adjacent first pressure sensors.

4. The liquid level measurement method according to claim 1, further comprising: Confirm that the plane for measuring the tilt angle is either above or below the oil level.

5. In the liquid level measurement method according to claim 4, the pressure data detected by the second pressure sensor is compared with 0. When the pressure data is greater than 0, the tilt angle measuring plane is below the oil surface; when the pressure data is less than or equal to 0, the tilt angle measuring plane is below the oil.

6. According to the liquid level measurement method of claim 5, when the tilt angle measuring plane is above the oil surface, a low liquid level alarm is triggered, prompting the operator to carry out subsequent handling work according to the low liquid level situation.

7. The liquid level measurement method according to claim 1, wherein the pressure data of multiple second pressure sensors are compared with each other, and when the pressure data are the same, it is confirmed that the probe is in a vertical state, and when the pressure data are different, it is confirmed that the probe is in an inclined state.

8. The liquid level measurement method according to claim 7, wherein the probe tilt angle is calculated based on the shape of the second pressure sensor and its projection on the horizontal plane, combined with the liquid pressure formula and spatial structure relationship.

9. The liquid level measurement method according to claim 1, wherein the liquid composition is determined to have changed by judging whether the liquid density between each first pressure sensor is the same, and when the first liquid density is different from the adjacent second liquid density and third liquid density, it is determined that the oil-water interface is located between the first pressure sensors corresponding to the first liquid density.

10. The liquid level measurement method according to claim 6, further comprising: The second and third liquid densities are stored as oil and water densities, respectively. The second liquid density is compared with the corresponding standard density of the stored oil for verification. When the error value of the comparison verification exceeds the allowable range, an alarm message is issued to prompt the operator to check the equipment or verify the oil quality. When the error value of the comparison verification does not exceed the allowable range, the second density is replaced with the standard density for storage.

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