A multifunctional servo level gauge and its real-time level measurement method

Abstract

This invention discloses a multifunctional servo level gauge and its real-time level measurement method, relating to the field of level measurement technology. The multifunctional servo level gauge performs real-time measurement of the liquid level. When the multifunctional float is immersed in the liquid to be measured for liquid parameter measurement, the following real-time measurement steps are executed to achieve continuous measurement of the current liquid level height: the microprocessor calculates the current liquid level height in real time based on the pressure value measured by the pressure sensor, the vertical distance the float descends, and the liquid density. This invention allows for continuous level calculation via the pressure sensor throughout the entire process of measuring physical parameters such as temperature, density, and interface while the float is immersed in the liquid, completely solving the problem of existing multifunctional servo level gauges losing their level monitoring capability when measuring non-level parameters. A single device can simultaneously meet the real-time level requirements of a safety interlock system and the multi-parameter measurement requirements of an automatic metering system, filling a technological gap in this field.

Description

Technical Field

[0001] This invention relates to the field of liquid level measurement technology, and in particular to a multifunctional servo liquid level gauge and its real-time liquid level measurement method. Background Technology

[0002] A servo level gauge is a high-precision contact-type tank metering device based on the feedback control principle of a servo motor. Its basic working principle is as follows: the servo mechanism drives the float up and down via a connector wound around a hub. When the float is at the liquid surface, buoyancy and gravity reach equilibrium, and the servo mechanism stops moving. At this point, the liquid level can be obtained by measuring the rotation angle or number of revolutions of the hub. Due to its advantages such as simple installation, ease of use, high metering accuracy, and good reliability, the servo level gauge has been widely used in tank metering in oil depots, refineries, chemical plants, LNG receiving terminals, and other similar settings.

[0003] To expand functionality, existing servo level gauges, especially intelligent floats, often integrate multiple measuring elements such as temperature sensors, density sensors, and oil-water interface sensors. This allows them to acquire physical parameters such as temperature, density, and interface at different depths within the liquid while simultaneously measuring the level. For example, the TM-80N automatic tank metering instrument and the BJLM-80H servo level gauge both offer multiple float options: a standard float for measuring only the level, a temperature float for measuring both level and temperature, and a density float for measuring level, temperature, and density. The TM-80N's intelligent float, with its built-in temperature sensor and density meter, can perform LNG-specific measurement modes, measuring up to 200 points in a single operation, comprehensively acquiring the stratified density and temperature distribution of the liquid within the tank.

[0004] However, the existing technology has the following problems: when the servo level gauge measures parameters other than the liquid level, the float must be submerged at different heights within the liquid to perform the measurement after the servo mechanism is released. During this process, the float detaches from the liquid surface, and the servo level gauge cannot detect the liquid level in real time. Since the servo mechanism typically takes a long time to lower the float into the liquid to measure other parameters—for example, the LNG-specific measurement mode requires measuring up to 200 points, which can take several minutes—if the liquid level in the tank changes rapidly during this period due to inflow or outflow, it can easily lead to serious safety accidents such as tank overflow or pump cavitation. Therefore, existing multi-functional servo level gauges cannot be used as safety interlocking level devices when measuring other parameters within the liquid.

[0005] Utility model patent CN222124476U discloses a multifunctional servo level gauge, which is a "dual float" scheme. This scheme achieves real-time monitoring of the liquid level when the main float is submerged by adding an auxiliary float to the connecting cable. This effectively solves the monitoring blind spot problem when the main float is out of the liquid surface, but it increases hardware cost and structural complexity, requiring an additional set of float mechanical structures.

[0006] Current safety regulations require that level gauges used for tank safety interlocks must be able to monitor liquid levels continuously and in real time, and typically require SIL certification. This necessitates the installation of two level gauges on the same tank: one dedicated to safety monitoring, such as a radar level gauge or a traditional servo level gauge, and the other a multi-functional servo level gauge for automatic metering. This significantly increases equipment investment, installation complexity, and subsequent maintenance workload, placing a substantial financial burden on users.

[0007] Therefore, there is an urgent need in this field for a multifunctional servo level gauge that can monitor the liquid level in real time while the float is submerged to measure other parameters, without increasing hardware costs, and a corresponding real-time liquid level measurement method. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention provides a multifunctional servo level gauge and a method for real-time level measurement. The technical solution adopted is as follows: A method for real-time liquid level measurement using a multi-functional servo level gauge, wherein the liquid level to be measured is measured in real time using a multi-functional servo level gauge; When the multi-functional float is immersed in the liquid to be measured to measure liquid parameters, the following real-time measurement steps are performed to achieve continuous measurement of the current liquid level height: Step a: The microprocessor obtains the vertical distance from the multi-functional float to the bottom of the tank by reading the operating parameters of the servo drive mechanism; Step b: Obtain the pressure value at its location using a pressure sensor; Step c: Obtain the density of the liquid to be tested using a multi-functional detection sensor module; Step d: The microprocessor calculates the current liquid level in real time based on the pressure value measured by the pressure sensor, the vertical distance the float descends, and the liquid density. Step e: Output the calculated current liquid level height to the safety interlock system.

[0009] Optionally, the microprocessor calculates the current liquid level height H in real time according to the following formula: ; in, P represents the vertical distance between the multi-functional float and the bottom of the tank after the float descends from its initial liquid level. P is the pressure value measured by the pressure sensor. The density of the liquid to be tested, It is the acceleration due to gravity. This is the fixed height offset of the pressure sensor relative to the position of the multi-functional float balancing liquid surface.

[0010] Optionally, when the pressure sensor is positioned above the balance fluid level of the multi-functional float... It takes a negative value, a positive value when it is below, and a zero value when it is on the same horizontal plane.

[0011] A multifunctional servo level gauge is disclosed, which implements a real-time liquid level measurement method. The multifunctional servo level gauge includes a servo drive mechanism, a traction component, and a multifunctional float. The servo drive mechanism is installed above the liquid surface to be measured and drives the multifunctional float to move up and down through the traction component. The multifunctional float includes a multifunctional detection sensor module, a pressure sensor, and a microprocessor. The multifunctional detection sensor module is used to detect the density and temperature of the liquid to be measured. The pressure sensor is used to measure the pressure value at the location of the multifunctional float when it is immersed in the liquid to be measured. The microprocessor is communicatively connected to the servo drive mechanism and reads the operating parameters of the servo drive mechanism. The multifunctional detection sensor module and the pressure sensor are electrically connected to the microprocessor, and the microprocessor executes steps a to e.

[0012] Optionally, the pressure sensor is fixedly installed on the upper, middle or lower part of the multi-functional float.

[0013] Optionally, when the pressure sensor is installed below the multi-functional float, the multi-functional servo level gauge simultaneously has two level measurement methods: traditional level measurement based on buoyancy balance and level calculation measurement based on pressure sensor. The two methods are mutually verified when the multi-functional float is on the liquid surface, and the pressure sensor calculation method works independently when the multi-functional float is submerged, forming a redundant measurement system.

[0014] Optionally, the multi-functional servo level gauge can simultaneously output at least two level signals and one pressure signal via a communication bus; the servo drive mechanism is also equipped with high level alarm relay contacts and low level alarm relay contacts, which are used to directly output switch signals based on the calculated level to the safety interlock system.

[0015] Optionally, the multifunctional float integrates multiple pressure sensors, which are installed in different positions, and the microprocessor performs data fusion or redundancy verification on the measurement values ​​of the multiple pressure sensors.

[0016] Optionally, the traction assembly includes a hub and a traction rope. The hub is mounted on the side of the servo drive mechanism via a rotating shaft. The traction rope is wound around the hub, with its two ends connected to the power output end of the servo drive mechanism and a multi-functional float, respectively. The traction rope is a wire connection structure or a tape connection structure with internally integrated wires.

[0017] Optionally, the multifunctional detection sensor module includes a density sensor, a temperature sensor, and an oil-water interface sensor.

[0018] In summary, the present invention has at least one of the following beneficial technical effects: This invention provides a multifunctional servo level gauge and its real-time level measurement method. Throughout the entire process of measuring physical parameters such as temperature, density, and interface while the float is immersed in the liquid, the level can still be continuously calculated via a pressure sensor. This completely solves the problem in existing multifunctional servo level gauges where the level monitoring capability is lost when measuring non-level parameters. A single device can simultaneously meet the real-time level requirements of a safety interlock system and the multi-parameter measurement requirements of an automatic metering system, filling a technological gap in this field.

[0019] Users no longer need to install two separate level gauges on the same storage tank, which significantly reduces equipment procurement costs, installation space requirements, and subsequent maintenance workload.

[0020] When the pressure sensor is installed below the float, the system can simultaneously obtain two liquid level measurement results based on two completely different physical principles—mechanical measurement based on buoyancy balance and electronic measurement based on the pressure sensor. The two methods serve as verification and backup for each other, significantly improving the system's fault tolerance. In abnormal situations such as float jamming or communication interruption, the redundant measurement method can provide continuous liquid level information, meeting the diverse redundancy requirements of SIL certification.

[0021] Compared with the existing dual-float mechanical redundancy scheme, the present invention only requires adding a pressure sensor and corresponding signal processing circuit to the original float, without changing the external structure and installation method of the existing servo level gauge. The increase in hardware cost is minimal, which has significant economic advantages. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of a multifunctional float immersed in the liquid to be measured in a usage scenario of a multifunctional servo level gauge according to the present invention. Figure 2 This is a schematic diagram of the multi-functional float structure of a multi-functional servo level gauge according to the present invention; Figure 3 This is a schematic diagram illustrating the electrical component connection principle of a multifunctional servo level gauge according to the present invention.

[0023] Explanation of reference numerals in the attached drawings: 1. Servo drive mechanism; 2. Traction assembly; 21. Wheel hub; 22. Traction rope; 3. Multifunctional detection sensor module; 31. Density sensor; 32. Temperature sensor; 33. Oil-water interface sensor; 4. Pressure sensor; 5. Microprocessor; 7. Float housing; 10. Main unit. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to the accompanying drawings.

[0025] This invention discloses a multifunctional servo level gauge and a method for real-time level measurement.

[0026] Reference Figures 1-3 Example 1: A method for real-time liquid level measurement using a multi-functional servo level gauge, wherein a multi-functional servo level gauge is used to measure the liquid level to be measured in real time. When the multi-functional float is immersed in the liquid to be measured to measure liquid parameters, the following real-time measurement steps are performed to achieve continuous measurement of the current liquid level height: Step a, the microprocessor 5 obtains the vertical distance the multi-functional float descends from its initial liquid surface position by reading the operating parameters of the servo drive mechanism 1; Step b: Obtain the pressure value at the location of the pressure sensor 4; Step c: Obtain the density of the liquid to be tested using the multi-functional detection sensor module 3; In step d, the microprocessor 5 calculates the current liquid level height in real time based on the pressure value measured by the pressure sensor 4, the vertical distance the float descends, and the liquid density. Step e: Output the calculated current liquid level height to the safety interlock system 100.

[0027] By employing the above technical solution, when the multifunctional float is immersed in the liquid to measure parameters such as density, temperature, or oil-water interface, the servo drive mechanism 1 releases the multifunctional float to a certain depth below the liquid surface via the traction component 2. The microprocessor 5 reads the operating parameters of the servo drive mechanism 1 in real time to obtain the displacement of the multifunctional float from its initial liquid surface position. Since the initial position is known, the vertical distance between the multifunctional float and the bottom of the tank is calculated. The pressure sensor 4 measures the hydrostatic pressure of the liquid at its location. The multifunctional detection sensor module 3 measures the density of the liquid currently being measured. The microprocessor 5 calculates the current liquid level height in real time based on the pressure value, vertical distance, and density, and sends this height value to the safety interlock system 100. The entire measurement process is uninterrupted, achieving continuous monitoring of the liquid level during float immersion.

[0028] Example 2: The microprocessor 5 calculates the current liquid level height H in real time according to the following formula: ; in, P represents the vertical distance between the multi-functional float and the bottom of the tank after the float descends from its initial liquid level position, and P is the pressure value measured by pressure sensor 4. The density of the liquid to be tested, It is the acceleration due to gravity. This is the fixed height offset of the pressure sensor 4 relative to the position of the multi-functional float balancing liquid surface.

[0029] By adopting the above technical solution, the microprocessor 5 uses a mathematical model based on the hydrostatic principle to calculate the liquid level, the formula being: .in This represents the thickness of the liquid column above pressure sensor 4, i.e., the vertical distance from pressure sensor 4 to the liquid surface. This refers to the distance between the multi-functional float and the bottom of the tank after the float descends from its initial liquid level, i.e., the current depth of the multi-functional float. Let A be the displacement of the servo drive mechanism 1 being read, and B be a known set value for the initial vertical distance B between the multi-functional float and the bottom of the tank. =BA can be easily calculated. Add the liquid column thickness to the descent depth, then subtract the fixed offset of the pressure sensor 4 relative to the float's equilibrium liquid surface position (microprocessor). This formula yields the current true liquid level height H. This formula ensures that the liquid level position can be accurately determined regardless of the depth to which the multi-functional float is submerged.

[0030] Example 3, when pressure sensor 4 is located above the balance liquid level of the multi-functional float It takes a negative value, a positive value when it is below, and a zero value when it is on the same horizontal plane.

[0031] By adopting the above technical solution The value depends on the installation position of pressure sensor 4 on the multi-functional float. When pressure sensor 4 is fixed above the equilibrium liquid level of the multi-functional float, the measurement point is higher than the float reference plane. The value is negative; when installed below, the measurement point is lower than the reference plane. It is a positive value; when installed on the same horizontal plane, The value is zero. Different values ​​allow the formula to automatically adapt to the actual installation height of pressure sensor 4, ensuring accurate liquid level calculation results.

[0032] Example 4: A multifunctional servo level gauge is provided to implement a real-time liquid level measurement method. The multifunctional servo level gauge includes a servo drive mechanism 1, a traction component 2, and a multifunctional float. The servo drive mechanism 1 is installed above the liquid surface to be measured and drives the multifunctional float to move up and down through the traction component 2. The multifunctional float includes a multifunctional detection sensor module 3, a pressure sensor 4, and a microprocessor 5. The multifunctional detection sensor module 3 is used to detect the density and temperature of the liquid to be measured. The pressure sensor 4 is used to measure the pressure value at the location of the multifunctional float when it is immersed in the liquid to be measured. The microprocessor 5 is communicatively connected to the servo drive mechanism 1 and reads the operating parameters of the servo drive mechanism 1. The multifunctional detection sensor module 3 and the pressure sensor 4 are electrically connected to the microprocessor 5, and the microprocessor 5 executes steps a to e.

[0033] By adopting the above technical solution, the multifunctional servo level gauge consists of three main parts: a servo drive mechanism 1, a traction component 2, and a multifunctional float. The servo drive mechanism 1 is fixed to the top of the storage tank and drives the multifunctional float to rise and fall through the traction component 2. The multifunctional float integrates a multifunctional detection sensor module 3, a pressure sensor 4, and a microprocessor 5. The multifunctional detection sensor module 3 is responsible for measuring the liquid density and temperature; the pressure sensor 4 collects pressure when the float is submerged; and the microprocessor 5 communicates with the servo drive mechanism 1 to obtain the descent distance. The microprocessor 5 is electrically connected to the above three modules and automatically executes all steps from data acquisition to level calculation and output to the safety interlock system 100.

[0034] In Example 5, the pressure sensor 4 is fixedly installed on the upper, middle or lower part of the multifunctional float.

[0035] By adopting the above technical solution, the pressure sensor 4 can be flexibly fixed at the upper, middle, or lower part of the multi-functional float according to the on-site working conditions. When installed at the upper part, the pressure sensor 4 is away from the sediment at the bottom of the tank, which is suitable for liquids containing silt or high viscosity; when installed in the middle part, it is usually... With a zero offset, no calibration is required, making on-site debugging extremely simple. When installed at the bottom, pressure sensor 4 is always submerged in the liquid, ensuring a stable measurement signal and providing redundancy with traditional buoyancy-balanced level measurements. Users can choose the optimal installation location based on media characteristics and maintenance schedules.

[0036] In Example 6, when the pressure sensor 4 is installed below the multi-functional float, the multi-functional servo level gauge simultaneously has two level measurement methods: traditional level measurement based on buoyancy balance and level calculation measurement based on pressure sensor. The two methods are mutually verified when the multi-functional float is on the liquid surface, and the pressure sensor calculation method works independently when the multi-functional float is submerged, forming a redundant measurement system.

[0037] By adopting the above technical solution, when the pressure sensor 4 is fixed below the multi-functional float, the servo level gauge naturally obtains two sets of level measurement channels with different physical principles. The first channel is a traditional buoyancy balance measurement, which is only effective when the multi-functional float is on the liquid surface; the second channel is a pressure sensor calculation measurement of the present invention, which continuously outputs the liquid level while the multi-functional float is submerged. When the multi-functional float returns to the liquid surface, both channels are effective simultaneously and can be compared and verified; if the deviation exceeds a preset threshold, the system issues a diagnostic alarm. When the multi-functional float is submerged, the second channel works independently, ensuring that the safety interlock system 100 always obtains real-time liquid level data, forming hardware-level redundancy protection.

[0038] In Example 7, the multi-functional servo level gauge simultaneously outputs at least two level signals and one pressure signal via a communication bus; the servo drive mechanism 1 is also provided with a high level alarm relay contact and a low level alarm relay contact, which are used to directly output a switch signal based on the calculated level to the safety interlock system 100.

[0039] By adopting the above technical solution, the multi-functional servo level gauge simultaneously sends three signals via fieldbus: the first level signal comes from traditional buoyancy balance measurement, the second level signal comes from continuous calculation measurement by a pressure sensor, and the third is the raw pressure signal. The servo drive mechanism 1 is also independently configured with high-level and low-level alarm relay contacts. When the calculated level exceeds the high-level threshold or falls below the low-level threshold, the relay contacts directly close or open, outputting a switching signal to the safety interlock system 100 without needing to go through a communication bus or host computer, thus meeting the requirements of the safety instrumented system for response speed and independence.

[0040] In Example 8, the multifunctional float integrates multiple pressure sensors 4, which are installed in different positions. The microprocessor 5 performs data fusion or redundancy verification on the measurement values ​​of the multiple pressure sensors.

[0041] By adopting the above technical solution, multiple pressure sensors 4 are installed on the multi-functional float, arranged at different heights. The microprocessor 5 simultaneously reads the measured values ​​from each pressure sensor, and obtains a more stable pressure input by averaging or using a weighted fusion algorithm, eliminating single-point random errors. When the reading of a pressure sensor significantly deviates from the reasonable range or deviates from other sensors by more than a set threshold, the microprocessor 5 automatically determines that the sensor is faulty, immediately switches to independent operation of the remaining normal sensors, and issues a maintenance alarm. This design achieves sensor-level redundancy, significantly improving the system's fault tolerance, and is particularly suitable for unattended tank farms.

[0042] In Example 9, the traction assembly 2 includes a hub 21 and a traction rope 22. The hub 21 is mounted on the side of the servo drive mechanism 1 via a rotating shaft. The traction rope 22 is wound around the hub 21, and its two ends are respectively connected to the power output end of the servo drive mechanism 1 and the multi-functional float. The traction rope 22 is a wire connection structure or a ruler-type connection structure with internally integrated wires.

[0043] By adopting the above technical solution, the traction assembly 2 consists of a hub 21 and a traction rope 22. The hub 21 is mounted on the side of the servo drive mechanism 1 via a rotating shaft, and the servo drive mechanism 1 drives the hub 21 to rotate in both directions. The traction rope 22 is wound around the hub 21, with one end fixed to the hub 21 and the other end connected to a multi-functional float. The traction rope 22 adopts two structural forms: a wire connection structure, suitable for media such as conventional hydraulic oil and chemicals; or a ruler-type connection structure with internally integrated wires, specifically designed for scenarios such as LNG that require multi-point dense measurement and the transmission of sensor signals. Both structures can reliably transmit traction force and support signal transmission.

[0044] Example 10: The multifunctional detection sensor module 3 includes a density sensor 31, a temperature sensor 32, and an oil-water interface sensor 33.

[0045] By adopting the above technical solution, the multifunctional detection sensor module 3 integrates three sensing elements: a density sensor 31 for real-time measurement of liquid density, providing the microprocessor ρ value for the liquid level calculation formula; a temperature sensor 32 for measuring liquid temperature at different depths, assisting in density correction and stratification analysis; and an oil-water interface sensor 33 for identifying the interface between the oil and water layers in the storage tank. The three sensors work together, enabling the multifunctional float to simultaneously acquire distribution data in three dimensions—density, temperature, and interface—during a single descent, fully meeting the needs of the automatic metering system.

[0046] The implementation principle of the present invention is illustrated below through specific embodiments: Taking a 5000-cubic-meter refined oil storage tank as an example, a multi-functional servo level gauge is installed on the top of the tank. This level gauge includes a servo drive mechanism 1, a traction assembly 2, and a multi-functional float. The servo drive mechanism 1 is fixed to the flange interface on the top of the tank. The traction assembly 2 consists of a hub 21 and a traction rope 22. The hub 21 is mounted on the side of the servo drive mechanism 1 via a rotating shaft. The traction rope 22 adopts a ruler-type connection structure with internally integrated wires. The traction rope 22 is wound around the hub 21, with one end fixed to the hub 21 and the other end connected to the multi-functional float.

[0047] The multi-functional float integrates a multi-functional detection sensor module 3, a pressure sensor 4, and a microprocessor 5. The multi-functional detection sensor module 3 includes a density sensor 31, a temperature sensor 32, and an oil-water interface sensor 33. The pressure sensor 4 is fixedly installed at the bottom of the multi-functional float. The microprocessor 5 is communicatively connected to the servo drive mechanism 1, reading the number of rotations of the hub 21 in real time and converting it into the length of the traction rope 22, i.e., the vertical distance the multi-functional float descends from its initial liquid surface position. The microprocessor 5 is electrically connected to both the multi-functional detection sensor module 3 and the pressure sensor 4.

[0048] After on-site installation, initial calibration is performed first. The multi-functional float is raised to the liquid surface, at which point buoyancy and gravity reach equilibrium, and the servo drive mechanism 1 records this position as the initial liquid surface position. Pressure sensor 4 measures the pressure value at the liquid surface, and microprocessor 5 calculates the fixed height offset of pressure sensor 4 relative to the equilibrium liquid surface position based on the known oil density and gravitational acceleration. ,Will Stored in microprocessor 5.

[0049] In this embodiment, the volume corresponding to each millimeter of height of the 5000 cubic meter storage tank is approximately 300 liters, and the oil inlet or outlet speed is designed to be 400 cubic meters per hour.

[0050] During normal operation of the storage tank, the multi-functional servo level gauge performs automatic metering tasks. The servo drive mechanism 1 lowers the multi-functional float to a height of 1.5 meters above the tank bottom via a traction rope 22 (the float's height refers to its distance from or relative to the tank bottom, which is the zero point), in order to measure the oil temperature and density at that depth. When the multi-functional float is immersed in the liquid being measured for liquid parameter measurement, the following real-time measurement steps are executed to achieve continuous measurement of the current liquid level height: Step a: Microprocessor 5 obtains the vertical distance between the multi-functional float and the bottom of the tank after the multi-functional float descends from its initial liquid level position. It is 1,500 meters.

[0051] In step b, pressure sensor 4 acquires the pressure value P at its location, which is 71220 Pascals.

[0052] In step c, the density sensor 31 in the multi-functional detection sensor module 3 acquires the density ρ of the liquid to be tested, which is 850 kg per cubic meter. At the same time, the temperature sensor 32 measures the temperature as 25 degrees Celsius.

[0053] Step d, microprocessor 5 according to formula ; Calculate the current liquid level in real time. Take the gravitational acceleration g as 9.8 m / s². The value is 0.050 meters (because pressure sensor 4 is installed below the multi-functional float). (Positive). Calculation process: =71220÷(9.8×850)=71220÷8330≈8.55 meters. Therefore, H=1.500+8.55-0.050=10.00 meters. That is, the current oil level in the storage tank is 10.00 meters.

[0054] In step e, the microprocessor 5 outputs the calculated current liquid level height of 10.00 meters to the safety interlock system 100 in real time via the RS485 ModBus communication bus.

[0055] As the multi-functional float continues to descend to other depths to measure more temperature and density points, steps a through e above are executed continuously at a frequency of 10 times per second. When the oil depot begins to fill the storage tank at a rate of 400 cubic meters per hour (approximately 0.111 cubic meters per second), the liquid level will rise rapidly. Based on the tank parameters (approximately 300 liters per millimeter, or 0.3 cubic meters per millimeter), the liquid level rise rate can be calculated to be approximately 400 ÷ 0.3 ≈ 1333 millimeters per hour, or approximately 1.333 meters per hour.

[0056] During the multi-point measurement of 50 points by the multi-functional float submerged in the liquid (estimated to take about 10 minutes), the microprocessor 5 continuously monitors and calculates the liquid level H as it gradually rises from 10.00 meters to approximately 10.22 meters (theoretical rise: 1.333 meters / hour × (10 / 60) hours ≈ 0.222 meters). When H reaches the preset high-level alarm threshold of 11.00 meters, the high-level alarm relay contact integrated on the servo drive mechanism 1 immediately closes, directly outputting a switching signal to the emergency shut-off valve without going through the safety interlock system 100. The emergency shut-off valve closes the oil inlet pipe within 0.5 seconds, preventing a tank overflow accident.

[0057] Meanwhile, since the pressure sensor 4 is installed below the multi-functional float, this servo level gauge has two liquid level measurement methods. When the multi-functional float returns to the liquid surface after completing multi-point measurements, the liquid level measured by the traditional buoyancy balance measurement method is 10.22 meters, which is completely consistent with the 10.22 meters measured by the pressure sensor continuous calculation method, and the cross-verification is successful. If the liquid level drops rapidly under oil discharge conditions, the same principle can prevent pump cavitation accidents. Throughout the entire process, the safety interlock system 100 continuously receives real-time liquid level data from the pressure sensor calculation method, and no monitoring blind spots occur.

[0058] This specific embodiment verifies the feasibility and reliability of the multi-functional servo level gauge in the dual scenarios of automatic metering and safety interlocking of a 5000 cubic meter finished oil storage tank. Its level measurement and response speed are fully capable of handling the oil inflow and outflow conditions of 400 cubic meters per hour.

[0059] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A multi-functional servo liquid level meter liquid level real-time measurement method, characterized in that, A multi-functional servo level gauge is used to measure the liquid level in real time. When the multi-functional float is immersed in the liquid to be measured to measure liquid parameters, the following real-time measurement steps are performed to achieve continuous measurement of the current liquid level height: Step a, the microprocessor (5) obtains the vertical distance from the multi-functional float to the bottom of the tank by reading the operating parameters of the servo drive mechanism (1); Step b, obtain the pressure value at its location through pressure sensor (4); Step c, the density of the liquid to be tested is obtained through the multifunctional detection sensor module (3); Step d, the microprocessor (5) calculates the current liquid level height in real time based on the pressure value measured by the pressure sensor (4), the vertical distance of the float's descent, and the liquid density; Step e: Output the calculated current liquid level height to the safety interlock system (100).

2. The method of claim 1, wherein the method is a real-time measurement method of a multi-functional servo liquid level meter, characterized by, The microprocessor (5) calculates the current liquid level height H in real time according to the following formula: ； wherein, P is the vertical distance between the multifunctional float and the tank bottom after the multifunctional float is lowered from the initial liquid level position, P is the density of the liquid to be measured, P is the acceleration of gravity, P is the fixed height offset of the pressure sensor (4) relative to the equilibrium liquid level position of the multifunctional float.

3. The method for real-time liquid level measurement of a multifunctional servo level gauge according to claim 2, characterized in that, When the pressure sensor (4) is above the balance liquid level of the multi-functional float, It takes a negative value, a positive value when it is below, and a zero value when it is on the same horizontal plane.

4. A multifunctional servo level gauge, characterized in that, To implement the real-time liquid level measurement method of the multifunctional servo level gauge as described in claim 3, the multifunctional servo level gauge includes a servo drive mechanism (1), a traction component (2), and a multifunctional float; the servo drive mechanism (1) is installed above the liquid surface to be measured, and drives the multifunctional float to move up and down through the traction component (2); the multifunctional float includes a multifunctional detection sensor module (3), a pressure sensor (4), and a microprocessor (5); the multifunctional detection sensor module (3) is used to detect the density and temperature of the liquid to be measured; the pressure sensor (4) is used to measure the pressure value at the location when the multifunctional float is immersed in the liquid to be measured; the microprocessor (5) is communicatively connected to the servo drive mechanism (1) and reads the operating parameters of the servo drive mechanism (1); the multifunctional detection sensor module (3) and the pressure sensor (4) are electrically connected to the microprocessor (5) respectively; the microprocessor (5) executes steps a to e.

5. A multifunctional servo level gauge according to claim 4, characterized in that: The pressure sensor (4) is fixedly installed on the upper, middle or lower part of the multi-functional float.

6. A multifunctional servo level gauge according to claim 4, characterized in that: When the pressure sensor (4) is installed below the multi-functional float, the multi-functional servo level gauge has two liquid level measurement methods: traditional liquid level measurement based on buoyancy balance and liquid level calculation measurement based on pressure sensor. The two methods verify each other when the multi-functional float is on the liquid surface, and the pressure sensor calculation method works independently when the multi-functional float is submerged, forming a redundant measurement system.

7. A multifunctional servo level gauge according to claim 4, characterized in that: The multi-functional servo level gauge outputs at least two level signals and one pressure signal simultaneously via a communication bus; the servo drive mechanism (1) is also provided with a high level alarm relay contact and a low level alarm relay contact, which are used to directly output a switch signal based on the calculated level to the safety interlock system (100).

8. A multifunctional servo level gauge according to claim 4, characterized in that: The multifunctional float integrates multiple pressure sensors (4), which are installed in different positions. The microprocessor (5) performs data fusion or redundancy verification on the measured values ​​of the multiple pressure sensors.

9. A multifunctional servo level gauge according to claim 4, characterized in that: The traction assembly (2) includes a hub (21) and a traction rope (22). The hub (21) is mounted on the side of the servo drive mechanism (1) via a rotating shaft. The traction rope (22) is wound around the hub (21) and its two ends are respectively connected to the power output end of the servo drive mechanism (1) and the multi-functional float. The traction rope (22) is a wire connection structure or a ruler-type connection structure with wires integrated inside.

10. The float of a multifunctional servo level gauge according to claim 4, characterized in that, The multifunctional detection sensor module (3) includes a density sensor (31), a temperature sensor (32), and an oil-water interface sensor (33).

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