A standard glass float calibration device and method
Patent Information
- Application Number
- CN202611305129.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-08-26
- Publication Date
- 2026-10-30
AI Technical Summary
[0011]本发明的目的在于提供一种标准玻璃浮子校准装置及校准方法，以解决上述背景技术中提出的现有直接比较法存在安全风险高、配液过程繁琐、配制难度大、配液种类多、效率低下、人工读数误差大以及校准液稳定性差问题
[0034]1.安全性大幅提升：无需使用硫酸、酒精、乙醚等危化品，仅需使用正十三烷等低毒、安全的工作液体，彻底消除了危化品管理、存储、使用过程中的安全风险。
Smart Images
Figure CN123008550A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of metrology and testing technology, specifically to a standard glass float calibration device and calibration method. Background Technology
[0002] Standard glass floats are core metrological standard instruments in the system for the transfer and traceability of liquid density values. They are widely used in the verification and calibration of working glass floats such as hydrometers, alcohol meters, and saccharimeters. The accuracy of their values directly affects the precision of trade settlement and product quality control in industries such as petroleum, chemical, pharmaceutical, and food.
[0003] Currently, the calibration of standard glass floats generally follows the direct comparison method according to JJF1709-2018 "Standard Glass Float Calibration Specification": a first-class standard hydrometer and the glass float to be calibrated are simultaneously immersed in the same calibration liquid. After both float stably, the reading of the first-class standard hydrometer is compared with the reading of the float to be calibrated to obtain the correction value of the float's reading. In practice, a calibration solution of corresponding density needs to be prepared using chemicals such as sulfuric acid, alcohol, and ether with pure water, based on the density range of the float to be calibrated. After repeated adjustments to reach the target density, the solution is poured into a glass graduated cylinder, kept at a constant temperature, and then the standard hydrometer and the float to be calibrated are placed inside. The readings are then manually read and the correction value is calculated. When calibrating different density points, a new calibration solution of the corresponding density needs to be prepared, and all operations must be repeated.
[0004] The direct comparison method described above has the following significant drawbacks in practical applications:
[0005] First, the calibration solution is a hazardous chemical with high safety risks. The calibration solution involves highly corrosive sulfuric acid and flammable and explosive chemicals such as alcohol and ether. Strict control of hazardous chemicals is required throughout the entire process of procurement, storage, preparation, use, and waste disposal. The operation requirements are high and the management costs are large. Once a leak or operational error occurs, it can easily cause personal injury and property damage.
[0006] Secondly, the solution preparation process is cumbersome and difficult. Calibrating standard glass floats at different density points requires preparing calibration solutions of varying densities. Each solution preparation necessitates precise calculation of the component ratios based on the target density, involving repeated additions, mixing, measurements, and adjustments to achieve the desired density value. This process is time-consuming and labor-intensive, demanding a high level of experience and skill from the operators.
[0007] Third, the variety of calibration solutions required leads to low efficiency. Standard glass floats typically require calibration at multiple density points, each necessitating the preparation of a different density calibration solution. Completing the calibration of all floats often necessitates preparing several or even dozens of different density calibration solutions. Each time a density point is changed, the measuring cylinder and float must be thoroughly cleaned, the solution prepared again, and the temperature restored, resulting in extremely low calibration efficiency.
[0008] Fourth, manual readings have significant errors. The direct comparison method relies on the operator visually reading the intersection point between the standard density meter and the liquid surface. Affected by factors such as operator parallax, the meniscus effect of the liquid surface, and lighting conditions, the repeatability of the readings is poor, introducing substantial human error.
[0009] Fifth, the calibration solution has poor stability. The density of the prepared calibration solution will change with factors such as temperature changes, solvent evaporation, and component sedimentation. During long-term calibration, the drift in liquid density will directly affect the accuracy of the calibration results.
[0010] Therefore, we propose a standard glass float calibration device and calibration method. Summary of the Invention
[0011] The purpose of this invention is to provide a standard glass float calibration device and calibration method to solve the problems of high safety risk, cumbersome solution preparation process, high preparation difficulty, many types of solutions, low efficiency, large error of manual reading and poor stability of calibration solution in the existing direct comparison method mentioned in the background art.
[0012] To achieve the above objectives, the present invention provides the following technical solution: a standard glass float calibration device, comprising an electronic balance, a constant temperature control unit, a float suspension device, an anti-buoyancy frame, a temperature measuring device, and a data acquisition and processing industrial control computer;
[0013] The electronic balance weighs the apparent mass of a standard glass float in air and after immersion in the working fluid.
[0014] The constant temperature control unit includes a constant temperature bath and a working liquid container. The working liquid container is placed inside the constant temperature bath and contains the working liquid. The constant temperature bath stabilizes the temperature of the working liquid at the calibrated nominal temperature.
[0015] The float suspension device includes a suspension bracket and a precision suspension wire. The suspension bracket is adapted to be installed on the weighing end of the electronic balance. The upper end of the precision suspension wire is connected to the suspension bracket, and the lower end of the precision suspension wire suspends the calibrated standard glass float.
[0016] The temperature measuring device includes a platinum resistance thermometer, which is placed inside the working fluid to collect the actual temperature of the working fluid in real time.
[0017] The anti-buoyancy frame is a detachable structure, and its own mass and volume have been pre-calibrated.
[0018] When the density of the standard glass float being calibrated is less than the density of the working fluid, the anti-buoyancy frame is mounted above the float and presses the float below the liquid surface by its own weight, ensuring that the float is completely submerged in the working fluid.
[0019] The data acquisition and processing industrial control computer is electrically connected to the electronic balance and the platinum resistance thermometer, respectively, to collect mass weighing data and temperature data, calculate the actual density value and indication correction value of the float based on Archimedes' buoyancy principle, and output the calibration results.
[0020] The working liquid in the working liquid container is n-tetrazane liquid.
[0021] The diameter of the hanging wire is no more than 0.1mm, and it is made of platinum wire or nylon wire.
[0022] This also includes an environmental meteorological monitor, which collects atmospheric pressure, ambient temperature, and humidity parameters of the calibrated environment in real time.
[0023] It also includes a lifting and adjusting mechanism, which is connected to the suspension bracket for transmission. The lifting and adjusting mechanism controls the rise and fall of the float, realizing the switching of the float between the air weighing position and the liquid immersion position.
[0024] A calibration method for a standard glass float density value calibration device includes the following steps:
[0025] S1 calibration preparation: Pour the working fluid into the working fluid container and place it in the thermostatic bath. Start the thermostatic bath to stabilize the working fluid temperature to the calibration nominal temperature. Use a platinum resistance thermometer to collect the actual temperature of the working fluid and obtain the standard density value of the working fluid at that temperature.
[0026] S2 Weighing in air: The cleaned and dried standard glass float to be calibrated is suspended below the electronic balance by a wire, so that the float is suspended in the air. After the balance reading stabilizes, the mass of the float in the air and the air density are read and the data are recorded.
[0027] Repeat the weighing multiple times and take the average value as the final result of the air weighing;
[0028] S3 Immersion State Judgment: Compare the nominal density of the calibrated float with the working fluid density. If the nominal density of the float is greater than or equal to the working fluid density, proceed directly to step S4; if the nominal density of the float is less than the working fluid density, assemble the pre-calibrated anti-buoyancy frame on the float and then proceed to step S4.
[0029] S4 Weighing in liquid: Control the float to descend and be fully immersed in the working liquid. After the float is stable and there are no bubbles on the surface, read the mass of the float in the working liquid and the air density at this time. Repeat the weighing multiple times and take the average value as the final result of the weighing in liquid.
[0030] S5 density value calculation: Based on Archimedes' principle of buoyancy, combined with the weighing results in air, the weighing results in liquid, the density of the working liquid, the density of air, and the expansion coefficient of the float, the actual density value of the corresponding scale of the calibrated float is calculated. Air buoyancy correction and temperature correction are introduced in the calculation process.
[0031] S6 Correction Value Calculation: Subtract the calculated actual density value from the nominal density value of the float to obtain the indication correction value for that scale point;
[0032] S7 Data Output: Summarize calibration data, complete measurement uncertainty assessment, and generate a calibration report.
[0033] The present invention has at least the following beneficial effects:
[0034] 1. Significantly improved safety: No need to use hazardous chemicals such as sulfuric acid, alcohol, or ether; only low-toxicity and safe working liquids such as n-tetrane are required, completely eliminating safety risks in the management, storage, and use of hazardous chemicals.
[0035] 2. Significantly improved calibration efficiency: There is no need to prepare calibration solutions of various densities. A single working liquid can complete the calibration of all float density points, reducing the calibration time from several days to several hours.
[0036] 3. Higher calibration accuracy: High-precision electronic balance is used for weighing, avoiding parallax errors caused by manual reading; through precise temperature control and strict data correction, the accuracy and repeatability of the calibration results are superior to the direct comparison method.
[0037] 4. Easy to operate: No need to frequently change calibration solution, no need to repeatedly clean float and measuring cylinder, the operation process is highly standardized, and the experience requirements of operators are low.
[0038] 5. Wide applicability: It can cover standard glass floats with various density ranges and is not limited by the density range of the calibration fluid. For floats with a density much lower than that of the working fluid, they can be completely immersed in the fluid using an anti-buoyancy frame to ensure calibration is feasible.
[0039] 6. Environmentally friendly: It does not use organic solvents or corrosive chemicals, and does not generate harmful waste liquids, meeting green environmental protection requirements. Attached Figure Description
[0040] Figure 1 This is a schematic diagram of the overall structure of the present invention;
[0041] Figure 2 This is a schematic diagram of the anti-floating frame structure of the present invention.
[0042] In the diagram: 1. Electronic balance; 2. Suspension bracket; 3. Suspension wire; 4. Standard glass float; 5. Constant temperature bath; 6. Working liquid; 7. Working liquid container; 8. Temperature measuring device; 9. Lifting and adjusting mechanism; 10. Data acquisition and processing industrial control computer; 11. Anti-buoyancy frame; 12. Environmental meteorological monitor. Detailed Implementation
[0043] 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, and 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.
[0044] Please see Figures 1 to 2 This invention provides a technical solution: a standard glass float calibration device and calibration method, which calibrates the density indication of a standard glass float based on the static weighing method and Archimedes' principle of buoyancy. The whole device includes an electronic balance 1, a suspension bracket 2, a suspension wire 3, a constant temperature bath 5, a working liquid container 7, a working liquid 6, a temperature measuring device 8, a lifting and adjusting mechanism 9, an anti-buoyancy frame 11, an environmental meteorological monitor 12, and a data acquisition and processing industrial control computer 10.
[0045] The calibration principle is as follows:
[0046] The standard glass float is weighed in air and in the working fluid. The volume of the part of the float immersed in the fluid is calculated based on the two weighing results. Then, the actual density value corresponding to the current scale of the float is calculated by combining the accurate density value of the working fluid at that temperature. The correction value at that point can be obtained by comparing it with the nominal density value of the float.
[0047] The core calculation formula is as follows:
[0048]
[0049] —The density of the liquid used for testing, in g / cm³;
[0050] —Air density when the float is weighed in air, g / cm³;
[0051] —Air density of the float when weighed in the test solution, g / cm³;
[0052] —The apparent mass of the float in air, g;
[0053] —The density of the weights is typically 8.0 g / cm³;
[0054] —The apparent mass of the float in the calibration solution at temperature T, in g;
[0055] β—Coefficient of thermal expansion of the working glass float. ;
[0056] g—acceleration due to gravity, m / s² .
[0057] Compare the calculated actual density value ρ with the nominal density value of the float. By comparison, the correction value at that point is obtained. .
[0058] Electronic balance 1 is a high-precision analytical balance, placed on a shockproof workbench. It has a weighing range of no less than 210g and a mass resolution of up to 0.1mg. It is used to weigh the apparent mass of the calibrated standard glass float 4 in air and after immersion in the working liquid, providing core mass data for density calculation.
[0059] The suspension bracket 2 is adapted to be installed at the weighing hook below the electronic balance 1, serving as the load-bearing structure for the float suspension;
[0060] The suspension wire 3 is made of platinum wire with a diameter of no more than 0.1 mm. The upper end is connected to the weighing end of the suspension bracket 2, and the lower end is used to suspend the standard glass float 4. The small diameter of the suspension wire 3 can reduce the influence of liquid surface tension and immersion volume on the weighing results.
[0061] The lifting adjustment mechanism 9 adopts a servo motor drive structure and is connected to the suspension bracket 2 for transmission. It can accurately control the lifting and lowering displacement of the float, realize the smooth and low-speed switching of the float between the air weighing position and the liquid immersion position, and avoid the float shaking and the generation of bubbles.
[0062] The constant temperature bath 5 is a high-precision constant temperature circulation bath with a temperature control accuracy of ±0.05℃. The working liquid container 7 is made of glass and is placed inside the constant temperature chamber of the constant temperature bath 5. The working liquid 6 is placed in the working liquid container 7 and is n-tetane liquid. This liquid has the characteristics of small density temperature coefficient, low volatility, low surface tension, stable chemical properties and low toxicity. As a calibration medium for static weighing, it can be used for a long time without frequent replacement.
[0063] The temperature measuring device 8 uses a precision platinum resistance thermometer with a temperature resolution of not less than 0.01℃. The probe is immersed in the working liquid 6 to collect the actual temperature value of the working liquid in real time, providing a basis for temperature correction and working liquid density determination.
[0064] The anti-buoyancy frame 11 is a detachable, lightweight structure made of polytetrafluoroethylene (PTFE). Its own mass and drainage volume are precisely calibrated in advance. When the density of the standard glass float 4 being calibrated is much smaller than that of the working liquid 6, the buoyancy force on the float is greater than its own weight, and it cannot be completely submerged in the liquid on its own. At this time, the anti-buoyancy frame 11 is assembled on top of the float, and the weight of the anti-buoyancy frame is used to force the float to be pressed below the liquid surface, ensuring that the float is completely submerged. During data processing, the influence of the anti-buoyancy frame's own mass and the submersion buoyancy force is deducted in advance to ensure the accuracy of the weighing results.
[0065] The environmental meteorological monitor 12, also known as the weather station, is deployed around the calibration device to collect environmental atmospheric pressure, ambient temperature, and relative humidity parameters in real time. It automatically calculates the real-time air density value and transmits it to the data acquisition and processing industrial control computer 10 for air buoyancy correction of the weighing results in the air.
[0066] The data acquisition and processing industrial control computer 10 adopts an industrial control computer structure and is electrically connected to the electronic balance 1, temperature measuring device 8, lifting adjustment mechanism 9, and environmental meteorological monitor 12. It has data acquisition, logic control, calculation analysis and report generation functions: it can automatically collect raw data such as mass, temperature and air density, and automatically complete the calculation of air buoyancy correction, temperature correction and actual density and correction value by the built-in calibration algorithm. It can evaluate the uncertainty of measurement results and automatically generate standardized calibration reports.
[0067] This example uses a standard glass float with a nominal density of 800 kg / m³ to be calibrated:
[0068] Step 1: Calibration Preparation
[0069] The working fluid, n-tetane, was injected into a glass working fluid container 7. The container was then placed in a thermostat bath 5. The thermostat bath 5 was started and the target temperature was set to 23.0℃. After the temperature stabilized, the actual working fluid temperature T = 23.01℃ was measured using a precision platinum resistance thermometer. The density of the working fluid at this temperature was obtained through solid density standard calibration. =756.23kg / .
[0070] Step 2: Weighing in the air
[0071] The standard glass float 4 to be calibrated is cleaned and thoroughly dried. It is then suspended below the suspension bracket 2 using a precision suspension wire 3, ensuring the float is suspended in the air and does not contact any surrounding objects. After the electronic balance 1 stabilizes, the apparent mass is read, and the real-time air density is collected via the environmental meteorological monitor 12. The weighing is repeated three times, and the arithmetic mean is taken to obtain the average apparent mass of the float in the air. =42.3565g.
[0072] Step 3: Determine the immersion status
[0073] Comparing the nominal density of the calibrated float (800 kg / m³) with the working liquid density (756.23 kg / m³), the nominal density of the float is greater than that of the working liquid. The float can be submerged on its own without the need for an anti-buoyancy frame, and can directly perform the weighing procedure in the liquid.
[0074] Step 4: Weighing in the liquid
[0075] The suspension bracket is slowly lowered by the lifting adjustment mechanism 9, allowing the standard glass float 4 to be completely immersed in the working liquid 6. After the float stops swaying, no air bubbles adhere to its surface, and the electronic balance reading stabilizes, the apparent mass in the liquid is read, and the air density is simultaneously recorded. This process is repeated three times, and the arithmetic mean is taken to obtain the average apparent mass of the float in the liquid. =15.2342g.
[0076] Step 5: Calculation of actual density value
[0077] The data acquisition and processing industrial control computer is based on Archimedes' principle of buoyancy. It substitutes parameters such as the mass of the air being weighed, the mass of the liquid being weighed, the density of the working liquid, the density of the air, the density of the weights, and the expansion coefficient of the float glass body. At the same time, it introduces air buoyancy correction and temperature correction to calculate the actual density value ρ=800.15kg / m³ corresponding to the scale point.
[0078] Step 6: Calculate the correction value
[0079] Compare the calculated actual density value with the nominal density value of the float. By subtracting 800.00 kg / m³, we obtain the correction value for the scale point: Δρ = 800.15 - 800.00 = +0.15 kg / m³.
[0080] Step 7: Report Generation
[0081] The system summarizes the correction values from all calibration points, completes the uncertainty assessment of the measurement results, and automatically generates a standardized calibration report containing calibration data, correction values, and expanded uncertainty.
[0082] For low-density standard glass floats with a nominal density less than that of the working liquid, a pre-calibrated anti-buoyancy frame is assembled on top of the float before liquid weighing, and the weight of the anti-buoyancy frame is used to press the float below the liquid surface. When calculating the data, the mass of the anti-buoyancy frame itself and the contribution of buoyancy generated by immersion are deducted in advance to obtain the mass of the float itself in the liquid. The subsequent calculation process is the same as the example above.
[0083] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.
[0084] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A standard glass float calibration device, characterized in that: include: Electronic balance, constant temperature control unit, float suspension device, anti-buoyancy frame, temperature measuring device, and industrial control computer for data acquisition and processing; The electronic balance weighs the apparent mass of a standard glass float in air and after immersion in the working liquid. The constant temperature control unit includes a constant temperature bath and a working liquid container. The working liquid container is placed inside the constant temperature bath and contains the working liquid. The constant temperature bath stabilizes the temperature of the working liquid at the calibrated nominal temperature. The float suspension device includes a suspension bracket and a suspension wire. The suspension bracket is adapted to be installed on the weighing end of the electronic balance. The upper end of the suspension wire is connected to the suspension bracket, and the lower end of the suspension wire suspends a calibrated standard glass float. The temperature measuring device includes a platinum resistance thermometer, which is placed inside the working fluid to collect the actual temperature of the working fluid in real time.
2. The standard glass float calibration device according to claim 1, characterized in that: The anti-buoyancy frame is a detachable structure, and its own mass and volume have been pre-calibrated; When the density of the standard glass float being calibrated is less than the density of the working fluid, the anti-buoyancy frame is mounted above the float and presses the float below the liquid surface by its own weight, ensuring that the float is completely submerged in the working fluid.
3. The standard glass float calibration device according to claim 1, characterized in that: The data acquisition and processing industrial control computer is electrically connected to the electronic balance and the platinum resistance thermometer, respectively, to collect mass weighing data and temperature data, calculate the actual density value and indication correction value of the float based on Archimedes' buoyancy principle, and output the calibration results.
4. The standard glass float calibration device according to claim 1, characterized in that: The working liquid in the working liquid container is n-tetrazane liquid.
5. The standard glass float calibration device according to claim 1, characterized in that: The diameter of the suspension wire is no greater than 0.1 mm, and it is made of platinum wire or nylon wire.
6. The standard glass float calibration device according to claim 1, characterized in that: It also includes an environmental meteorological monitor, which collects atmospheric pressure, ambient temperature and humidity parameters of the calibration environment in real time.
7. The standard glass float calibration device according to claim 1, characterized in that: It also includes a lifting adjustment mechanism, which is connected to the suspension bracket for transmission. The lifting adjustment mechanism controls the rise and fall of the float to realize the switching of the float between the air weighing position and the liquid immersion position.
8. A calibration method for a standard glass float calibration device, using the calibration device described in any one of claims 1-7, characterized in that, Includes the following steps: S1 calibration preparation: Pour the working fluid into the working fluid container and place it in the thermostatic bath. Start the thermostatic bath to stabilize the working fluid temperature to the calibration nominal temperature. Use a platinum resistance thermometer to collect the actual temperature of the working fluid and obtain the standard density value of the working fluid at that temperature. S2 Weighing in air: The cleaned and dried standard glass float to be calibrated is suspended below the electronic balance by a wire, so that the float is suspended in the air. After the balance reading stabilizes, the mass of the float in the air and the air density are read and the data are recorded. Repeat the weighing multiple times and take the average value as the final result of the air weighing; S3 Immersion State Judgment: Compare the nominal density of the calibrated float with the working fluid density. If the nominal density of the float is greater than or equal to the working fluid density, proceed directly to step S4; if the nominal density of the float is less than the working fluid density, assemble the pre-calibrated anti-buoyancy frame on the float and then proceed to step S4. S4 Weighing in liquid: Control the float to descend and be fully immersed in the working liquid. After the float is stable and there are no bubbles on the surface, read the mass of the float in the working liquid and the air density at this time. Repeat the weighing multiple times and take the average value as the final result of the weighing in liquid. S5 density value calculation: Based on Archimedes' principle of buoyancy, combined with the weighing results in air, the weighing results in liquid, the density of the working liquid, the density of air, and the expansion coefficient of the float, the actual density value of the corresponding scale of the calibrated float is calculated. Air buoyancy correction and temperature correction are introduced in the calculation process. S6 Correction Value Calculation: Subtract the calculated actual density value from the nominal density value of the float to obtain the indication correction value for that scale point; S7 Data Output: Summarize calibration data, complete measurement uncertainty assessment, and generate a calibration report.