Device for capacity calibration and calibration method

Abstract

The invention discloses a device for capacity calibration and a calibration method. The device comprises an operation table, a weighing structure, an adjusting structure and a protective cover, and the weighing structure comprises a weighing cup and a weighing module; wherein the weighing cup is used for calibrating a to-be-measured container, the weighing cup is arranged on the face, away from the operation table, of the weighing module, the weighing module is used for weighing the weighing cup, and the weighing module is placed on the operation table; the adjusting structure is used for automatically adjusting the position and the liquid injection amount of the to-be-measured container, the adjusting structure is arranged on one side of the operation table, and the protective cover is arranged on the outer side of the weighing cup and connected to the weighing module. A structural design of integrating a weighing structure and an adjusting structure is adopted, and a protective cover is arranged on the weighing module, so that the error rate caused by fatigue of personnel is reduced, the single calibration time is shortened, the high automation of the capacity calibration process is realized, the accuracy, reliability and operation efficiency in the calibration process are improved, and the production cost is reduced. And the applicability of the device is effectively enhanced.

Description

Technical Field

[0001] This invention relates to the technical field of capacity calibration, and in particular to an apparatus for capacity calibration and a calibration method using the apparatus. Background Technology

[0002] Volumetric calibration is an indispensable basic metrological task in laboratories, industrial production, and quality inspection institutions. Its accuracy directly affects the accuracy of product quality control, scientific experimental data, and trade settlements. In the fields of pharmaceuticals, chemicals, and food testing, glass volumetric instruments (such as volumetric flasks, graduated cylinders, and pipettes) and plastic volumetric instruments (such as polypropylene volumetric flasks and polyethylene measuring cups) are the most widely used volumetric measuring instruments. Traditional calibration methods are based on Archimedes' principle, calculating the actual volume value by weighing the mass of pure water contained in the volumetric instrument and considering factors such as water temperature and the temperature of the vessel walls.

[0003] However, existing calibration methods suffer from three major drawbacks: high reliance on manual operation, with fatigue-induced errors leading to higher error rates; significant impact from environmental factors, with temperature changes causing differential deformation of measuring instruments; and insufficient equipment coordination, which can affect reading stability. To address these issues, this invention proposes a new solution. Summary of the Invention

[0004] The present invention aims to at least solve one of the aforementioned technical problems existing in the prior art. Therefore, the object of the present invention is to provide an apparatus and a calibration method for capacity calibration.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An apparatus for capacity calibration, comprising: Control panel; A weighing structure, comprising a weighing cup and a weighing module; wherein the weighing cup is used to calibrate the container to be tested, the weighing cup is disposed on the side of the weighing module away from the operating table, the weighing module is used to weigh the weighing cup, and the weighing module is placed on the operating table; An adjustment structure is provided for automatically adjusting the position and liquid volume of the test container, and the adjustment structure is located on one side of the operating table. A protective cover is disposed on the outside of the weighing cup and connected to the weighing module.

[0006] In the capacity calibration device described above, a first limiting mechanism is provided between the weighing cup and the weighing module, the first limiting mechanism being used to prevent the weighing cup from detaching from the weighing module.

[0007] As described above, in a capacity calibration device, the adjustment structure includes an adjustment bracket for automatic adjustment and a control system for automatic adjustment control. The adjustment bracket is connected to the side of the operating table, and the weighing module and the adjustment bracket are electrically connected to the control system. The adjustment bracket includes a bracket body and a clamping mechanism for fastening the container to be tested. The bracket body is connected to the operating table, and the clamping mechanism is connected to the bracket body.

[0008] As described above, in a capacity calibration device, the clamping mechanism includes a first clamping member and a second clamping member for fixing the container to be tested; the first clamping member and the second clamping member are spaced apart on the support body along the length direction of the support body.

[0009] As described above, the device for capacity calibration further includes a first adjusting displacement device and a second adjusting displacement device. The first adjusting displacement device and the second adjusting displacement device are electrically connected to the control system, and the first adjusting displacement device and the second adjusting displacement device are spaced apart on the support body. The first clamping member and the second clamping member are connected to the first adjusting displacement device and the second adjusting displacement device, respectively. The first clamping member and the second clamping member are used to adjust the position of the container to be tested.

[0010] As described above, in a capacity calibration device, the adjusting bracket further includes a bracket adjusting displacement assembly for adjusting the bracket body, the bracket adjusting displacement assembly being electrically connected to the control system; the bracket adjusting displacement assembly is connected to the end of the bracket body along the side of the operating table away from the weighing structure.

[0011] The device for capacity calibration described above further includes a temperature sensor for detecting the liquid and the container wall, a non-contact capacitive level sensor for detecting the liquid level, and a MEMS tilt sensor for detecting the tilt angle of the operating platform. The temperature sensor, the non-contact capacitive level sensor, and the MEMS tilt sensor are electrically connected to the control system. The MEMS tilt sensor is located on the side of the operating platform away from the weighing structure. A plurality of temperature sensors are equidistantly located on the inner wall of the weighing cup, and the non-contact capacitive level sensor is located on the outer wall of the container to be tested.

[0012] The device for capacity calibration described above further includes an auxiliary verification module for assisting the non-contact capacitive level sensor in verifying the liquid level. The auxiliary verification module is electrically connected to the control system and is located on the side of the adjustment bracket.

[0013] The device for capacity calibration described above further includes a liquid injection module located outside the operating table. The liquid injection module includes a peristaltic pump, a liquid injection tube, and an adjustable injection head for injecting liquid. The peristaltic pump is electrically connected to the control system, and the liquid injection tube is installed inside the peristaltic pump. One end of the liquid injection tube is connected to a reservoir, and the other end is connected to the adjustable injection head for liquid injection.

[0014] The present invention provides a capacity calibration method for use in a capacity calibration apparatus as described above, comprising the following steps: S1. Pre-preparation stage: Place the container to be tested on the adjustment structure, and use the adjustment structure to adaptively clamp and actively level the container; the weighing cup is first detached, and then the information is collected and fed back to the adjustment structure. S2, Liquid Injection: Inject liquid into the container to be tested and monitor the injection volume in real time; S3. Meniscus Locking and Data Acquisition: When the real-time liquid level enters the range of ±1mL from the preset liquid level mark, the injection speed is reduced by adjusting the structure; when the slope of the capacitance-height curve |dC / dh|>the preset value, the point of change when |dC / dh|>the preset value is determined as the lowest point of the meniscus, the adjusting structure automatically locks the meniscus, and then the liquid after being brought to volume is injected into the weighing cup, and the weighing module is simultaneously triggered to record the mass of the liquid and collect the temperature of the liquid and the weighing cup and feed it back to the adjusting structure.

[0015] The beneficial effects of this invention are as follows: By integrating the weighing structure and the adjustment structure with automatic adjustment function into the operating table and centrally controlling them by the control system, the manual operation links are reduced, effectively overcoming the high dependence on manual operation in traditional methods, reducing the error rate caused by human fatigue, and reducing the single calibration time, thus achieving a high degree of automation in the capacity calibration process. At the same time, the device of this application can effectively isolate environmental airflow interference by setting a protective cover, and, combined with the adjustment structure, accurately control the position and liquid volume of the container to be tested, solving the reading stability problem caused by insufficient coordination of traditional equipment. It can also actively compensate for the differential deformation of the container to be tested caused by changes in ambient temperature, thereby significantly improving the accuracy, reliability, and operational efficiency of the calibration process and effectively enhancing the applicability of the device. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention; Figure 2 For the corresponding Figure 1 Enlarged view of the A-section structure; Figure 3 For the corresponding Figure 1 Enlarged view of the structure of section B; Figure 4This is a schematic diagram of the structure of the bracket adjustment displacement assembly installed on the bracket body according to an embodiment of the present invention; Figure 5 This is a flowchart illustrating the operation of the control system according to an embodiment of the present invention. Figure 6 This is a calibration block diagram for an embodiment of the present invention.

[0017] Reference numerals: 1-Operating table; 2-Weighing structure; 21-Weighing cup; 211-First connecting part; 22-Weighing module; 221-Protective cover; 222-First fastening part; 31-Adjusting bracket; 311-Bracket body; 312-Clamping mechanism; 3121-First clamping component; 3122-Second clamping component; 313-First adjusting displacement device; 314-Second adjusting displacement device; 315-Bracket adjusting displacement group; 32-Control system; 4-Rigid adapter rod; 6-Non-contact capacitive liquid level sensor; 7-Auxiliary verification module; 71-High-speed camera; 72-Automatic telescopic rod; 8-Injection module; 81-Peristaltic pump; 82-Injection pipe; 83-Adjustable water injection head. Detailed Implementation

[0018] The present invention will be further described in detail below through specific embodiments.

[0019] like Figures 1-6 As shown, an embodiment of the present invention provides an apparatus for capacity calibration, comprising: The system comprises an operating platform 1, a weighing structure 2, an adjusting structure, and a protective cover 221. The weighing structure 2 includes a weighing cup 21 and a weighing module 22. The weighing cup 21 is used to calibrate the container to be tested. The weighing cup 21 is located on the side of the weighing module 22 away from the operating platform 1. The weighing module 22 is used to weigh the weighing cup 21 and is placed on the operating platform 1. The adjusting structure is used to automatically adjust the position and liquid volume of the container to be tested. The adjusting structure is located on one side of the operating platform 1. The protective cover 221 is located on the outside of the weighing cup 21 and connected to the weighing module 22.

[0020] In this embodiment of the invention, the protective cover 221 is an airflow shield that can be directly fitted over the weighing cup 21 and movably placed on the weighing module 22 to improve the convenience of the calibration process. The protective cover 221 is preferably a transparent polycarbonate cover, which reduces the airflow disturbance inside the protective cover 221 to below 0.1 m / s to ensure the stability of the reading of the weighing module 22. In this embodiment of the invention, the device effectively isolates the environmental airflow interference through the protective cover 221 of the weighing module 22, and combines the adjustment structure to accurately control the position and liquid volume of the container to be tested, effectively solving the reading stability problem caused by insufficient coordination of traditional equipment, and effectively improving the accuracy and reliability of the device in the calibration process. In this embodiment of the invention, the weighing module 22 is a high-precision electronic balance (resolution 0.0001g), which can effectively enhance the accuracy of the reading.

[0021] Specifically, a first limiting mechanism 4 is provided between the weighing cup 21 and the weighing module 22. The first limiting mechanism 4 is used to restrict the weighing cup 21 from detaching from the weighing module 22.

[0022] In this embodiment of the invention, the weighing cup 21 is provided with a first connecting part 211 at one end facing the weighing module 22, and the weighing module 22 is provided with a first fastening part 222 at one end facing the weighing cup 21. The first connecting part 211 is connected to the first fastening part 222 via a first limiting mechanism to limit the weighing cup 21, thereby preventing the weighing cup 21 from detaching from the weighing module 22 and enhancing the stability during the testing process.

[0023] Preferably, the first fastening part 222 is the first threaded interface of the electronic balance, the first connecting part 211 is the second threaded interface provided at the bottom of the weighing cup 21, and the first limiting mechanism is a rigid adapter rod with connecting threads at both ends. Then, the two ends of the rigid adapter rod are respectively connected to the first threaded interface and the second threaded interface to fasten the weighing cup 21 to the electronic balance, thereby eliminating the transfer disturbance of the weighing cup 21 and enhancing the reliability and stability of the device during the calibration process.

[0024] Furthermore, the adjustment structure includes an adjustment bracket 31 for automatic adjustment and a control system 32 for automatic adjustment control. The adjustment bracket 31 is connected to the side of the operating table 1. The weighing module 22 and the adjustment bracket 31 are electrically connected to the control system 32 respectively. The adjustment bracket 31 includes a bracket body 311 and a clamping mechanism 312 for fastening the container to be tested. The bracket body 311 is connected to the operating table 1, and the clamping mechanism 312 is connected to the bracket body 311.

[0025] In this embodiment of the invention, the control system 32 is equipped with a central controller, which synchronously fuses the collected data and outputs accurate calibration results through a dynamic compensation algorithm.

[0026] In this embodiment of the invention, the weighing module 22 and the adjusting bracket 31 are electrically connected to the control system 32 so that the weighing module 22 and the adjusting bracket 31 can be uniformly controlled by the central controller; at the same time, the data collected by the weighing module 22 is processed by a dynamic compensation algorithm to ensure the accuracy of the data collected by the weighing module 22.

[0027] In this embodiment of the invention, the support body 311 is preferably a ball screw, which has a lead screw and two lead screw nuts. The limiting component 312 is connected to the two lead screw nuts respectively, so that the two lead screw nuts can be moved by the rotation of the lead screw, thereby driving the limiting component 312 to reciprocate. The adjusting support 31 also includes a stepper motor (not shown in the figure), which is electrically connected to the control system 32. The stepper motor is connected to the operating table 1 and rotates with the lead screw, so that the stepper motor can be controlled by the central controller to drive the lead screw to rotate.

[0028] In some embodiments, the stepper motor and the lead screw can be connected by a coupling, a synchronous belt, or a gear. In this embodiment of the invention, a gear connection is preferred, in which the stepper motor meshes with the lead screw through a gear set to drive the lead screw to rotate.

[0029] In some embodiments, the operating table 1 is provided with a lead screw mounting hole, and a first connecting sleeve is provided in the lead screw mounting hole. The lead screw is rotatably connected in the first connecting sleeve to ensure that the stepper motor can drive the lead screw to rotate and to reduce frictional damage between the lead screw and the operating table 1.

[0030] Furthermore, the clamping mechanism 312 includes a first clamping member 3121 and a second clamping member 3122 for fixing the container to be tested; along the length direction of the support body 311, the first clamping member 3121 and the second clamping member 3122 are spaced apart on the support body 311.

[0031] In this embodiment of the invention, the first clamping member 3121 is a first clamping jaw, and the second clamping member 3122 is a second clamping jaw. The first clamping jaw and the second clamping jaw are respectively connected to two lead screw nuts, so as to adjust the relative position of the first clamping jaw and the second clamping jaw by rotating the lead screw nuts on the lead screw.

[0032] Preferably, the first and second grippers are pneumatic grippers, so that they can be used for various measuring instruments and achieve automatic clamping of various measuring instruments. In this embodiment of the invention, the first and second grippers are provided with force sensors and thermoplastic elastomers. The thermoplastic elastomers are respectively sleeved on the first and second grippers to ensure that the first and second grippers provide sufficient friction force to the measuring instrument without damaging it. The force sensors are respectively installed on the first and second grippers and electrically connected to the central controller in the control system 32 to control the clamping force of the first and second grippers and ensure the safety of the measuring instrument during the calibration process.

[0033] Furthermore, the adjusting bracket 31 also includes a first adjusting displacement device 313 and a second adjusting displacement device 314 for adjusting the positions of the first clamping member 3121 and the second clamping member 3122. The first adjusting displacement device 313 and the second adjusting displacement device 314 are electrically connected to the control system 32, and the first adjusting displacement device 313 and the second adjusting displacement device 314 are spaced apart on the bracket body 311. The first clamping member 3121 and the second clamping member 3122 are respectively connected to the first adjusting displacement device 313 and the second adjusting displacement device 314, so that the first adjusting displacement device 313 and the second adjusting displacement device 314 drive the first clamping member 3121 and the second clamping member 3122 to adjust the position of the container to be measured.

[0034] In this embodiment of the invention, the first adjusting displacement device 313 and the second adjusting displacement device 314 are respectively connected to two lead screw nuts, and the first clamp and the second clamp are respectively connected to the first adjusting displacement device 313 and the second adjusting displacement device 314. The measuring instrument is a glass measuring instrument or a plastic measuring instrument. The first adjusting displacement device 313 and the second adjusting displacement device 314 are preferably piezoelectric ceramic micro displacement devices. Through the fine adjustment of the piezoelectric ceramic micro displacement device, the overload of the limiting component 312 can be effectively avoided to prevent the plastic measuring instrument from deforming, thereby improving the reliability of the testing process.

[0035] Furthermore, the adjusting bracket 31 also includes a bracket adjusting displacement assembly 315 for adjusting the bracket body 311, the bracket adjusting displacement assembly 315 being electrically connected to the control system 32; along the direction of the side of the operating table 1 away from the weighing structure 2, the bracket adjusting displacement assembly 315 is connected to the end of the bracket body 311.

[0036] In this embodiment of the invention, the support adjustment displacement group 315 is composed of multiple piezoelectric ceramic actuators, preferably three in number, to ensure that the piezoelectric ceramic actuators can be connected to the adjustment support body 311 at equal angles, and the tilt of the adjustment support body 311 is adjusted by the central controller in the control system 32, ensuring that the verticality error of the device to be measured is <0.1°, thereby improving the accuracy and reliability of the calibration process.

[0037] The device for capacity calibration provided in this embodiment of the invention further includes a temperature sensor for detecting the liquid and the container wall, a non-contact capacitive level sensor 6 for detecting the liquid level, and a MEMS tilt sensor for detecting the tilt of the operating platform 1. The temperature sensor, the non-contact capacitive level sensor 6, and the MEMS tilt sensor are electrically connected to the control system 32. The MEMS tilt sensor is located on the side of the operating platform 1 away from the weighing structure 2. Multiple temperature sensors are equidistantly located on the inner wall of the weighing cup 21, and the non-contact capacitive level sensor 6 is located on the outer wall of the container to be tested.

[0038] In this embodiment of the invention, the weighing cup 21 adopts a multi-layer composite structure design, with the base layer made of soda-lime glass (volume expansion coefficient 25×10⁻⁶). -6 / ℃) or modified polypropylene (volume expansion coefficient 110×10 -6 / ℃), capable of adaptive rotation according to the calibration object; the functional layer adopts a distributed temperature sensor array structure design, by embedding multiple sets of Pt1000 platinum resistance films in the cup wall of weighing cup 21 and electrically connecting them with the central controller in control system 32, distributed at 90° intervals, and combined with the cup wall of weighing cup 21 through sputtering process to form a distributed temperature sensor with a thickness ≤0.1mm, avoiding disturbance to the liquid flow field, allowing the temperature sensor to directly contact the liquid being measured, thereby controlling the measurement accuracy within ±0.1℃.

[0039] In this embodiment of the invention, the non-contact capacitive level sensor 6 uses the differential capacitance principle to detect the liquid level. The non-contact capacitive level sensor 6 is electrically connected to the central controller in the control system 32. For glass volumetric vessels, two rectangular copper electrodes are symmetrically attached to the outer wall of the vessel and spaced apart, so that the two rectangular copper electrodes are respectively connected to the C1 / C2 interface of the non-contact capacitive level sensor 6 to form a differential capacitor, thereby performing real-time capacitance detection on the glass volumetric vessel. For plastic volumetric vessels, the body of the plastic volumetric vessel is used as the dielectric, and a fan-shaped electrode array is arranged on the bottom and side wall of the plastic volumetric vessel and connected to the C1 / C2 interface of the non-contact capacitive level sensor 6 to form a differential capacitor, so as to improve the sensitivity of bottom blind zone detection, thereby achieving accurate identification of liquid level (meniscus) based on the differential capacitance principle, breaking through the limitations of traditional visual methods.

[0040] In this embodiment of the invention, a MEMS tilt sensor is connected to the operating table 1 to detect the tilt of the operating table 1 and feed it back to the central controller in the control system 32. The central controller then sends a command to the bracket adjustment displacement group 315, thereby adjusting the tilt of the adjustment bracket body 311 to ensure the verticality of the installation of the device to be measured.

[0041] The device for capacity calibration provided in this embodiment of the invention further includes an auxiliary verification module 7 for assisting the non-contact capacitive liquid level sensor 6 in verifying the liquid level. The auxiliary verification module 7 is electrically connected to the control system 32 and is located on the side of the adjustment bracket 31.

[0042] In this embodiment of the invention, the auxiliary verification module 7 includes a high-speed camera 71 and an automatic telescopic rod 72. The automatic telescopic rod 72 is fixedly connected to the operating table 1. The high-speed camera 71 is connected to the automatic telescopic rod 72 and electrically connected to the central controller. The height of the high-speed camera 71 is adjusted by the automatic telescopic rod 72 to assist the non-contact capacitive liquid level sensor 6 in verifying the real-time liquid level and feeding it back to the central controller, thereby improving the accuracy of the liquid injection process. In this embodiment of the invention, the automatic telescopic rod 72 is preferably a commercially available automatic telescopic rod to enhance the ease of installation of the auxiliary verification module 7 and reduce production costs.

[0043] In this embodiment of the invention, the auxiliary verification module 7 is disposed on the side of the adjustment bracket 31, preferably fixed on the operating table 1; in some embodiments, the auxiliary verification module 7 can be configured as a movable and adjustable structure, so that the auxiliary verification module 7 can be disposed around the side of the adjustment bracket 31, thereby improving the flexibility of the calibration process.

[0044] The device for capacity calibration provided in this embodiment of the invention further includes a liquid injection module 8, which is located outside the operating table 1. The liquid injection module 8 includes a peristaltic pump 81, a liquid injection pipe 82, and an adjustable water injection head 83 for injecting liquid. The peristaltic pump 81 is electrically connected to the control system 32, and the liquid injection pipe 82 is installed inside the peristaltic pump 81. One end of the liquid injection pipe 82 is connected to a liquid reservoir, and the other end is connected to the adjustable water injection head 83 for water injection.

[0045] In this embodiment of the invention, a non-contact capacitive liquid level sensor 6 is installed on a peristaltic pump 81, so that the non-contact capacitive liquid level sensor 6 detects changes in liquid level and feeds them back to the central controller, thereby controlling the peristaltic pump 81 to decrease or increase speed to adjust the injection volume. In this embodiment of the invention, the outlet of the adjustable water head 83 is provided with an umbrella-shaped diffuser so that the water flow is in a laminar state through the umbrella-shaped diffuser, avoiding splashing during the injection process and improving the reliability of the injection process. Understandably, the reservoir is used to store distilled water or deionized water; due to the differences in the devices to be measured, the adjustable water inlet head 83 is placed manually to ensure that the adjustable water inlet head 83 is kept within a distance of 10-15mm from the liquid surface, so as to enhance the adaptability to each device to be measured.

[0046] A capacity calibration method for a capacity calibration apparatus as described above includes the following steps: S1. Pre-preparation stage: The container to be tested is placed on the adjusting bracket 31 and adaptively clamped by the first and second grippers; the MEMS tilt sensor detects the tilt of the operating table 1 and feeds it back to the central controller in the control system 32. The central controller activates the first adjusting displacement device 313, the second adjusting displacement device 314, and the bracket adjusting displacement group 315 to actively level the container and ensure the verticality of the device to be measured; the weighing cup 21 is tare and the feedback is sent to the control system 32. The adjustable water injection head 83 is manually lowered to the preset height to ensure that the adjustable water injection head 83 is kept within 10-15mm of the liquid surface to prevent liquid splashing during the injection process and causing errors. In this embodiment of the invention, the maximum thrust of the piezoelectric ceramic micro-displacement device is ≥50N to ensure smoothness during the verticality adjustment process; In some embodiments of the invention, the degree of automation in the liquid injection process can be improved by fixing the adjustable injection head 83 to the automatic telescopic rod and setting a displacement sensor at the outlet of the adjustable injection head 83. S2, Liquid Injection: The peristaltic pump 81 injects liquid into the container to be tested through the adjustable injection head 83 according to the S-shaped flow curve. The non-contact capacitive liquid level sensor 6 monitors the real-time liquid level of the container to be tested. When it approaches the mark, the auxiliary verification module 7 is triggered to assist the non-contact capacitive liquid level sensor 6 in verification to ensure the accuracy of liquid injection. S3. Meniscus Locking and Data Acquisition: The meniscus is the curved liquid surface at the contact point between the liquid and the solid, bent by surface tension. When the non-contact capacitive level sensor 6 and the auxiliary verification module 7 monitor the real-time liquid level to reach 90%, i.e., the real-time liquid level enters the range of ±1mL from the mark, the control system 32 enters the fine-tuning mode. The peristaltic pump 81 is controlled to slow down to 0.1m / s through the central controller, increasing the sampling rate of the non-contact capacitive level sensor 6 to 1kHz. At the same time, the non-contact capacitive level sensor 6 collects real-time liquid level data and feeds it back to the central controller to calculate the slope k=|dC / dh| of the capacitance-height curve in real time. In this embodiment of the invention, the capacitance change rate threshold method is used to identify the meniscus. Distilled water is preferably used for liquid injection. The threshold of distilled water is 190.5pF / m, i.e., the preset value is set to 190.5 pF / m, and the threshold range of the meniscus is set to 180-200 pF / m. When k is continuously in the 180–200 pF / m range for multiple points and at least once ≥ 190.5 pF / m, the meniscus is identified. When pF / m, the height corresponding to the maximum k value that meets the conditions is determined as the lowest point of the meniscus. At the same time, the central processing unit of the control system 32 identifies and automatically locks the meniscus. Then, the liquid after being brought to a constant volume is injected into the weighing cup 21, and the weighing module 22 is triggered to record the mass of the liquid. The temperature sensor collects the temperature of the liquid and the weighing cup 21 every 100ms and feeds it back to the control system 32. In this embodiment of the invention, different methods are used to inject liquid into the weighing cup 21 for different measuring instruments. For volumetric flasks: the mouth of the volumetric flask is directly attached to the inner wall of the weighing cup 21, and then the body of the volumetric flask is slowly rotated to inject liquid, allowing the liquid to slide down the cup wall, leaving the last drop at the mouth for 5 seconds, and the liquid is collected by gently touching the cup wall with the tip of the stopper. For burettes / pipettes: the tip of the burette / pipette is attached to the inner wall of the weighing cup 21 at a 45° angle, liquid is poured to the mark and then paused for 15 seconds, and the last drop is "guided" down by the cup wall. Liquid should not be transferred by blowing air or shaking. For graduated cylinders / measuring cups: the mouth of the graduated cylinder / measuring cup is attached to the inner wall of the weighing cup 21, and the liquid is poured at a uniform speed, paused for 5 seconds to collect the liquid. If the mouth is short, a φ4 mm glass rod can be inserted to guide the flow against the wall, thereby avoiding liquid splashing and improving the reliability of the calibration process. S4. Capacity Calculation and Output: The collected data is transmitted to the offline certificate editing terminal via a wireless connector for certificate editing.

[0047] In this embodiment of the invention, the control system 32 is further provided with a wireless connector, which is electrically connected to the central controller to transmit the collected data to the offline terminal of the Nine-Top Certificate Editor; the wireless connector is either a Bluetooth module or a Wi-Fi module to improve the convenience of data transmission.

[0048] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. An apparatus for capacity calibration, characterized in that, include: Control panel (1); The weighing structure (2) includes a weighing cup (21) and a weighing module (22); wherein the weighing cup (21) is used to calibrate the container to be tested, the weighing cup (21) is disposed on the side of the weighing module (22) away from the operating table (1), the weighing module (22) is used to weigh the weighing cup (21), and the weighing module (22) is placed on the operating table (1); An adjustment structure is provided for automatically adjusting the position and liquid volume of the container to be tested. The adjustment structure is located on one side of the operating table (1). A protective cover (221) is disposed on the outside of the weighing cup (21) and connected to the weighing module (22).

2. The apparatus for capacity calibration according to claim 1, characterized in that, A first limiting mechanism (4) is provided between the weighing cup (21) and the weighing module (22), and the first limiting mechanism (4) is used to restrict the weighing cup (21) from detaching from the weighing module (22).

3. The apparatus for capacity calibration according to claim 1, characterized in that, The adjustment structure includes an adjustment bracket (31) for automatic adjustment and a control system (32) for automatic adjustment control. The adjustment bracket (31) is connected to the side of the operating table (1). The weighing module (22) and the adjustment bracket (31) are electrically connected to the control system (32). The adjustment bracket (31) includes a bracket body (311) and a clamping mechanism (312) for fastening the container to be tested. The bracket body (311) is connected to the operating table (1), and the clamping mechanism (312) is connected to the bracket body (311).

4. The apparatus for capacity calibration according to claim 3, characterized in that, The clamping mechanism (312) includes a first clamping member (3121) and a second clamping member (3122) for fixing the container to be tested; along the length direction of the support body (311), the first clamping member (3121) and the second clamping member (3122) are spaced apart on the support body (311).

5. The apparatus for capacity calibration according to claim 4, characterized in that, The adjustment bracket (31) further includes a first adjustment displacement device (313) and a second adjustment displacement device (314). The first adjustment displacement device (313) and the second adjustment displacement device (314) are electrically connected to the control system (32) respectively. The first adjustment displacement device (313) and the second adjustment displacement device (314) are spaced apart on the bracket body (311). The first clamping member (3121) and the second clamping member (3122) are respectively connected to the first adjustment displacement device (313) and the second adjustment displacement device (314). The first clamping member (3121) and the second clamping member (3122) are used to adjust the position of the container to be tested.

6. The apparatus for capacity calibration according to claim 3, characterized in that, The adjusting bracket (31) further includes a bracket adjusting displacement group (315) for adjusting the bracket body (311), the bracket adjusting displacement group (315) being electrically connected to the control system (32); the bracket adjusting displacement group (315) is connected to the end of the bracket body (311) along the side of the operating table (1) away from the weighing structure (2).

7. The apparatus for capacity calibration according to claim 3, characterized in that, It also includes a temperature sensor for detecting the liquid and the container wall, a non-contact capacitive liquid level sensor (6) for detecting the liquid level, and a MEMS tilt sensor for detecting the tilt of the operating platform (1). The temperature sensor, the non-contact capacitive liquid level sensor (6), and the MEMS tilt sensor are electrically connected to the control system (32). The MEMS tilt sensor is located on the side of the operating platform (1) away from the weighing structure (2). Multiple temperature sensors are equidistantly located on the inner wall of the weighing cup (21). The non-contact capacitive liquid level sensor (6) is located on the outer wall of the container to be tested.

8. The apparatus for capacity calibration according to claim 7, characterized in that, It also includes an auxiliary verification module (7) for assisting the non-contact capacitive liquid level sensor (6) in verifying the liquid level. The auxiliary verification module (7) is electrically connected to the control system (32) and is located on the side of the adjustment bracket (31).

9. The apparatus for capacity calibration according to claim 3, characterized in that, It also includes a liquid injection module (8), which is located outside the operating table (1). The liquid injection module (8) includes a peristaltic pump (81), a liquid injection pipe (82), and an adjustable water injection head (83) for injecting liquid. The peristaltic pump (81) is electrically connected to the control system (32), and the liquid injection pipe (82) is installed inside the peristaltic pump (81). One end of the liquid injection pipe (82) is connected to the liquid reservoir, and the other end is connected to the adjustable water injection head (83) for water injection.

10. A capacity calibration method, used in the apparatus for capacity calibration as described in any one of claims 1-9, characterized in that, Includes the following steps: S1, Pre-preparation stage: Place the container to be tested on the adjustment structure, and use the adjustment structure to adaptively clamp and actively level the container; the weighing cup (21) first removes the tare weight, and then the information is collected and fed back to the adjustment structure; S2, Liquid Injection: Inject liquid into the container to be tested and monitor the injection volume in real time; S3, Meniscus Locking and Data Acquisition: When the real-time liquid level enters the range of ±1mL of the preset liquid level mark, the injection speed is reduced by adjusting the structure; when the slope of the capacitance-height curve |dC / dh|> the preset value, the point of change when |dC / dh|> the preset value is determined as the lowest point of the meniscus, the adjusting structure automatically locks the meniscus, and then the liquid after volume adjustment is injected into the weighing cup (21), and the weighing module (22) is triggered to record the mass of the liquid and collect the temperature of the liquid and the weighing cup (21) and feed it back to the adjusting structure.

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