Mass flow meter calibration device and mass flow meter online calibration method

Abstract

The application discloses a kind of mass flowmeter calibration device and mass flowmeter online calibration method, it is related to flowmeter calibration technical field, including first standard measure and second standard measure, first standard measure is set on second standard measure, first standard measure is communicated with second standard measure, first standard measure is set with first valve on the communicating pipeline of second standard measure, second standard measure is set with liquid outlet, second valve is set on liquid outlet, first standard measure is set for with the liquid inlet of being communicated with the fluid conveying pipeline of the mass flowmeter to be calibrated on, third valve is set on liquid inlet, first standard measure and second standard measure are all set with liquid level detection equipment;The application mass flowmeter calibration device adopts volumetric method detection, small, low in cost, high accuracy, it is convenient for production site transportation and movement, can be completed online calibration under the condition that production line does not stop production.

Description

Technical Field

[0001] This invention relates to the field of flow meter calibration technology, specifically to a mass flow meter calibration device and an online calibration method for mass flow meters. Background Technology

[0002] Mass flow meters are widely used in the fields of liquor, petroleum refining, power generation and chemical industry. In particular, in the liquor industry, the vast majority of liquor companies use mass flow meters to measure the liquor during filling. The accuracy of the measurement value is directly related to the fairness of trade settlement and the direct interests of liquor production enterprises.

[0003] Currently, commonly used mass flow meter calibration methods include offline calibration and online calibration. Offline calibration methods, such as the static mass method, while highly accurate, require the flow meter under test to be sent to a laboratory for calibration, which not only affects on-site production but also often results in varying degrees of inaccuracy during transportation. Online calibration methods, such as the field standard meter method, rely on high-precision standard meters for calibration, leading to higher procurement and maintenance costs. The calibration devices used in commonly used online calibration methods also suffer from drawbacks such as large size, difficulty in on-site transportation, complex operation, and low accuracy.

[0004] Therefore, there is an urgent need for an online calibration device for mass flow meters that is small in size, low in cost, highly accurate, and easy to transport and operate on-site. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a mass flow meter calibration device and an online calibration method for mass flow meters. The device employs a volumetric method for testing, resulting in a small size, low cost, and high accuracy. It is also convenient for transportation and relocation on the production site and can perform online calibration of the mass flow meter under test without interrupting production.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] A mass flow meter calibration device includes: a first standard measuring vessel and a second standard measuring vessel. The first standard measuring vessel is disposed above the second standard measuring vessel and is connected to the second standard measuring vessel. A first valve is provided on the connecting pipeline between the first and second standard measuring vessels. The second standard measuring vessel is provided with an outlet and a second valve. The first standard measuring vessel is provided with an inlet for connecting to the fluid delivery pipeline of the mass flow meter to be calibrated and a third valve. Liquid level detection devices are provided in both the first and second standard measuring vessels. Breathing valves for connecting to the outside are provided in both the first and second standard measuring vessels. The volume of the first standard measuring vessel is larger than the volume of the second standard measuring vessel.

[0008] Preferably, both the first and second standard measuring instruments are provided with mounting brackets at their lower parts, and the mounting brackets are detachably connected to the first and second standard measuring instruments via snap-fit ​​connections.

[0009] Preferably, the liquid level detection device, the first valve, and the second valve are all electrically connected to the control system.

[0010] Preferably, the liquid level detection device is a high-precision liquid level gauge.

[0011] Preferably, the second standard measuring instrument is equipped with a densitometer.

[0012] Preferably, both the first and second standard measuring instruments are equipped with a temperature sensor, a pressure sensor, and a transmitter.

[0013] Preferably, the bottoms of both the first and second standard measuring instruments are funnel-shaped, and the lowest point of the first standard measuring instrument is connected to the top of the second standard measuring instrument through a connecting pipe.

[0014] Preferably, the second standard measuring instrument is provided with a spiral flow guiding structure for optimizing the liquid flow pattern. The spiral flow guiding structure includes a flow guiding path. The starting end of the flow guiding path corresponds to the communication port between the second standard measuring instrument and the first standard measuring instrument, and the ending end of the flow guiding path extends to the side vertical plane of the second standard measuring instrument.

[0015] Preferably, the mass flow meter calibration device further includes a circulation pump, the inlet of which is connected to the outlet, and the outlet of which is connected to the inlet of the mass flow meter to be calibrated.

[0016] This invention also provides an online calibration method for a mass flow meter, comprising the following steps:

[0017] S1: Connect the inlet of the mass flow meter calibration device to the fluid delivery pipeline;

[0018] S2: Initialize the calibration device, reset the calibration system, set the estimated instantaneous flow rate of the liquid, open the first and third valves, close the second valve, and allow the liquid to flow through the mass flow meter to be calibrated, starting from the inlet.

[0019] S3: Adjust the liquid flow rate according to the site conditions and keep it stable. The second standard measuring instrument will then begin measurement.

[0020] S4: The liquid level detection device detects the liquid level in the second standard volumetric container. The temperature sensor and density meter start measuring. When the liquid level detection device detects that the liquid level in the second standard volumetric container has risen to the specified height, the pressure sensor starts measuring, the first valve closes, the second valve opens, the liquid is drained from the second standard volumetric container, and the liquid continues to be injected into the first standard volumetric container. The calibration system records the first set of monitoring data.

[0021] S5: When the liquid level detection device detects that the second standard volumetric container has finished draining, the second valve closes and the first valve opens, and the liquid flows from the first standard volumetric container into the second standard volumetric container;

[0022] S6: Repeat steps S4 to S5 above until the test time ends, then close all valves and stop the injection.

[0023] S7: Based on the remaining liquid in the first and second standard measuring instruments, the last set of monitoring data is generated, and the calibration system optimizes and statistically analyzes each set of monitoring data.

[0024] S8: Obtain the cumulative mass flow rate value of the mass flow meter calibration device, compare it with the cumulative flow rate value measured by the mass flow meter to be calibrated, calculate the error, and realize the calibration of the mass flow meter to be calibrated.

[0025] The present invention achieves the following main technical effects compared to the prior art:

[0026] The mass flow meter calibration device disclosed in this invention adopts the volumetric method for detection, which is small in size, low in cost, and high in accuracy. It is easy to transport and move on the production site and can complete online calibration without stopping the production line.

[0027] The other technical solutions of this invention achieve the following technical effects compared to the prior art:

[0028] Based on high-precision liquid level detection equipment and an online density meter, combined with a dynamic compensation algorithm that uses temperature and pressure to correct density in real time, the liquid density value is corrected, thereby accurately calculating the actual liquid mass. ， It enables simultaneous acquisition and error compensation of multiple parameters, reducing the impact of fluctuations in on-site operating conditions on calibration results.

[0029] The standard measuring instrument features an internal spiral flow guide structure that optimizes the liquid flow pattern, suppresses foam generation during liquid flow, and improves the accuracy of liquid level detection. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the mass flow meter calibration device in an embodiment of the present invention;

[0032] Figure 2 This is a calibration flowchart of the mass flow meter calibration device in an embodiment of the present invention;

[0033] Figure 3 This is a flowchart illustrating the dynamic compensation process for density measurements in an embodiment of the present invention.

[0034] Among them, 1. First standard measuring instrument; 2. Second standard measuring instrument; 3. First valve; 4. Second valve; 5. Liquid inlet; 6. Liquid level detection equipment; 7. Liquid outlet; 8. Third valve. Detailed Implementation

[0035] 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.

[0036] The purpose of this invention is to provide a mass flow meter calibration device and an online calibration method for mass flow meters. It adopts a volumetric method for testing, is small in size, low in cost, and highly accurate. It is easy to transport and move on the production site, and can complete the online calibration of the mass flow meter under test without stopping the production line.

[0037] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] refer to Figure 1The mass flow meter calibration device disclosed in this embodiment includes a first standard measuring vessel 1 and a second standard measuring vessel 2. The first standard measuring vessel 1 is disposed above the second standard measuring vessel 2 and is connected to the second standard measuring vessel 2. In this embodiment, both the first standard measuring vessel 1 and the second standard measuring vessel 2 are 0.025 grade 304 stainless steel standard volumetric containers. A first valve 3 is provided on the connecting pipeline between the first standard measuring vessel 1 and the second standard measuring vessel 2, and an outlet 7 is provided on the second standard measuring vessel 2. A second valve 4 is provided on the outlet 7 for controlling the flow rate of the second standard measuring vessel. The first standard measuring vessel 1 is equipped with an inlet 5 for connecting to the fluid delivery pipeline of the mass flow meter to be calibrated. A third valve 8 is installed on the inlet 5 to control the injection of liquid into the first standard measuring vessel 1. Both the first and second standard measuring vessels 1 and 2 are equipped with level detection devices 6 for detecting the liquid level. Both the first and second standard measuring vessels 1 and 2 are equipped with breather valves that connect to the outside environment to ensure smooth liquid injection and discharge. When liquid is injected into the first standard measuring vessel 1 through the inlet 5, the first valve 3 opens. When the first standard measuring vessel 1 and the second standard measuring vessel 2 are in the open state, the second valve 4 is in the closed state. The breather valves on the first standard measuring vessel 1 and the second standard measuring vessel 2 can prevent positive pressure from forming inside the measuring vessel, ensuring smooth liquid injection. When the liquid in the second standard measuring vessel 2 is discharged through the outlet 7, the first valve 3 is in the closed state and the second valve 4 is in the open state. The breather valve on the second standard measuring vessel 2 can prevent negative pressure from forming inside the second standard measuring vessel 2, ensuring smooth liquid discharge. When the second standard measuring vessel 2 is discharging liquid, the first standard measuring vessel 1 is also being injected simultaneously. The breather valve on the first standard measuring vessel 1 can... To prevent positive pressure from forming inside the first standard measuring vessel 1 and ensure smooth liquid injection, the volume of the first standard measuring vessel 1 is larger than that of the second standard measuring vessel 2. This prevents the calibration from being affected by the first standard measuring vessel 1 being filled with liquid when the second standard measuring vessel 2 is draining. In this embodiment, the volumes of the first standard measuring vessel 1 and the second standard measuring vessel 2 are 300L and 250L, respectively. The mass flow meter calibration device of this invention adopts volumetric testing, is small in size, low in cost, and highly accurate. It is easy to transport and move on the production site and can complete online calibration without stopping the production line.

[0039] The lower part of the first standard measuring instrument 1 and the second standard measuring instrument 2 are both provided with mounting brackets. The mounting brackets are detachably connected to the first standard measuring instrument 1 and the second standard measuring instrument 2 by snap-fit. The mounting brackets fix the position of the first standard measuring instrument 1 and the second standard measuring instrument 2, and the snap-fit ​​facilitates the assembly and disassembly of the first standard measuring instrument 1 and the second standard measuring instrument 2.

[0040] The lower mounting bracket of the second standard measuring instrument 2 is equipped with rollers to facilitate the movement of the calibration device on the production site.

[0041] The outlet 7 is located at the bottom of the second standard volumetric 2 to ensure that the liquid in the second standard volumetric 2 can be drained.

[0042] The first valve 3 and the second valve 4 are pneumatic ball valves with a leakage level of VI, and are equipped with a power air source system, including an air compressor, pneumatic triplet, pipelines, etc., to ensure the normal operation of the pneumatic components on site; of course, pneumatic butterfly valves or other valves that can be opened and closed can also be used. The third valve 8 is a manual valve.

[0043] The liquid level detection device 6, the first valve 3, and the second valve 4 are all electrically connected to the control system. The control system is a programmable control system with a human-machine interface design to achieve automatic control during calibration, reduce the difficulty of using the device and the complexity of operation, and improve detection accuracy and efficiency.

[0044] The liquid level detection device 6 is a high-precision liquid level gauge, which can realize high-precision measurement of liquid level. By setting the full tank and empty tank height thresholds of the first standard measuring instrument 1 and the second standard measuring instrument 2, the device outputs the action signals of the first valve 3 and the second valve 4 when the thresholds are reached. The liquid level detection device 6 can also be a grating ruler.

[0045] In one embodiment, a densitometer is installed on the second standard volumetric instrument 2. The densitometer is a direct-reading densitometer that can directly obtain the liquid density value. The calibration system calculates the average value based on the effective density value measured in real time during the liquid injection process and then uses it for the calculation of fluid mass, providing a basis for the mass calculation in the calibration process. Both the first standard volumetric instrument 1 and the second standard volumetric instrument 2 are equipped with temperature sensors, pressure sensors and transmitters. The density value is corrected by measuring the liquid temperature and pressure in the standard volumetric instrument to ensure the accuracy of the density calculation.

[0046] In this embodiment, the mass flow meter calibration device has a calibration system that integrates data acquisition, automatic control, information input, and numerical calculation functions. The calibration system is responsible for the acquisition of the entire device's operating data (liquid temperature, pressure, density, volume, flow rate), real-time monitoring of measurement process data (liquid level), automatic calculation of fluid mass flow rate data, timing of the measurement process, counting of liquid injection and discharge, data storage of calibration process data, and error calculation (flow rate indication error). The calibration system has a complete database in the background, which has the functions of storing common models, technical parameters, historical test records, and test report generation of mass flow meters to be calibrated. The field power supply components of the calibration device have explosion-proof functions.

[0047] In one embodiment, the bottoms of the first standard measuring instrument 1 and the second standard measuring instrument 2 are both funnel-shaped. The lowest point of the first standard measuring instrument 1 is connected to the top of the second standard measuring instrument 2 through a connecting pipe. The funnel-shaped bottom ensures that the liquid in the first standard measuring instrument 1 can flow into the second standard measuring instrument 2 more conveniently by its own weight, and ensures that the liquid in the second standard measuring instrument 2 can be completely drained.

[0048] In this embodiment, the liquid inlet 5 is located at the bottom of the first standard volumetric 1. Compared with other locations of the liquid inlet 5, the liquid can be injected from the bottom of the first standard volumetric 1, which can effectively avoid the liquid from impacting the liquid surface and generating a large amount of foam when the liquid flows down, thus improving the accuracy of liquid level recognition.

[0049] The second standard measuring instrument 2 is equipped with a spiral flow guiding structure for optimizing the liquid flow pattern. The spiral flow guiding structure includes a flow guiding path. The starting end of the flow guiding path corresponds to the connection port between the second standard measuring instrument 2 and the first standard measuring instrument 1, and the ending end of the flow guiding path extends to the vertical plane of the side of the second standard measuring instrument 2. The spiral flow guiding structure can optimize the liquid flow pattern, changing the original vertically falling fluid pattern into a spiral falling pattern along the flow guiding path. This can suppress foam generation and improve the accuracy of liquid level recognition. The spiral flow guiding structure can be a series of raised ribs extending upward from the container inlet along the inner wall, or it can be a spiral blade attached to the inner wall. The whole structure is a continuous spiral flow guiding path, which can realize the guidance of liquid flow.

[0050] In the actual calibration process, if it is necessary to maintain the normal flow of fluid on site while calibrating, it is necessary to select a suitable reducing pipe according to the pipe diameter of the fluid delivery pipeline on site, and use a quick-release valve to install the rear end of the second valve 4 and the front end of the third valve 8 onto the fluid delivery pipeline through the reducing pipe; the calibration system collects digital / analog signals from sensors such as liquid level, density, temperature, and pressure, and uses a controller to control the opening and closing of the first valve 3 and the second valve 4. The calibration device is initialized, the calibration system values ​​are zeroed, the second valve 4 is closed, and the first valve 3 is opened. Then, the corresponding parameters of the mass flow meter to be calibrated and the operating parameters of the calibration device are set in the calibration system. The third valve 8 is manually opened to begin injecting liquid into the calibration device, and the calibration system starts timing. Liquid flows into the second standard volumetric container 2, and the level gauge measures the liquid level. When the liquid level in the second standard volumetric container 2 reaches the target value, the control system outputs a control signal to the first valve 3, which closes. After closing, the second valve 4 is opened to drain the liquid, and the calibration system counts one drainage cycle. After the level gauge detects that all liquid has been drained, the control system outputs a control signal to the second valve 4, which closes. After closing, the first valve 3 is opened. During this period, liquid is continuously injected into the first standard volumetric container 1 through the inlet 5 and the outlet... 7. Liquid enters the production site operating system; the liquid injected into the first standard volumetric jar 1 re-enters the second standard volumetric jar 2, and the level gauge begins measurement, entering the second measurement cycle; during the calibration process, the calibration system collects and corrects temperature, pressure, and density data in real time through temperature transmitters, pressure transmitters, and density meters; starting from the official start of timing (while simultaneously recording the cumulative flow value of the mass flow meter to be calibrated), after running for 15 minutes (while recording the instantaneous flow value of the mass flow meter to be calibrated), the third valve 8 is closed (while simultaneously recording the cumulative flow value of the mass flow meter to be calibrated), and the measurement stops; at this time, the running time is T, the number of times the second standard volumetric jar 2 drains is S, the measuring volume of the second standard volumetric jar 2 is V0, the current liquid capacity of the first standard volumetric jar 1 is V1, the liquid density is ρ, and the cumulative flow meter is m³ / s. 标 The flow rate indication error Δm is calculated, and the instantaneous and cumulative values ​​of mass flow rate are calculated by the calibration system.

[0051] Cumulative volume: V = V0 × S + V1

[0052] Cumulative flow: m 标 =V×ρ

[0053] Instantaneous flow rate = m 示 / T

[0054] The cumulative flow m calculated by the calibration system 标 and instantaneous flow rate, and the cumulative value m of the mass flow meter to be calibrated. 示 Calculate the flow rate indication error for this test, based on the instantaneous flow rate.

[0055] Flow rate indication error:

[0056]

[0057] On the one hand, fluctuations in on-site temperature can affect the density of the liquid. ρ Temperature changes can affect the parameters of the pressure sensor's sensitive element, thus influencing the pressure measurement. Furthermore, during calibration, the time difference between the triggering of the first valve 3's closing signal and its completion can cause deviations in the actual volume (liquid level) due to variations in the instantaneous flow rate during the injection process. This deviation can be corrected using the pressure measurement.

[0058] The calibration system uses temperature and pressure measurements, and dynamically compensates for density measurements using the PSO-BP algorithm. It employs a multi-parameter coupling method to achieve autonomous verification of liquid level, temperature, density, and pressure values, and finally achieves compensation and correction for each set of monitoring data during the calibration process.

[0059] The calibration values ​​recorded during laboratory calibration of temperature sensors, pressure sensors, and a density meter were used as sample data for the artificial neural network. The sample data were randomly selected at a 7:3 ratio as training and testing samples. A dynamic compensation model between density measurements and temperature and pressure measurements was then established based on the PSO-BP algorithm. First, the BP neural network structure was established, setting the input layer, output layer, number of hidden layers, and number of hidden layer nodes. The particle swarm size and maximum number of iterations were also set. Finally, the neuron weights and thresholds of the BP neural network were used as the positions of the particles to be optimized. The initial particle velocity was initialized. v Initial position x Determine the current optimal fitness value for an individual. P best and global best fitness value G best .

[0060] In each subsequent population iteration, the particle velocity is updated based on the individual optimal and global optimal fitness values. v and location x This updates the particle's velocity and position.

[0061]

[0062]

[0063] Next, calculate and update the individual's optimal fitness value. P best and global best fitness value G best This yields the fitness value F of the current particle. For each particle, if F > 0. Pbest Then update P best =F. Then compare the individual best fitness value of each particle with the global best fitness value. If... P best > G best Then update G best = P best The iteration ends when the maximum number of iterations is reached or the global optimal fitness value meets the accuracy requirements; otherwise, it returns to the velocity and position update process.

[0064] The system outputs the position of the particle corresponding to the globally optimal fitness value and uses this result to initialize the weights and thresholds of the backpropagation (BP) algorithm. Based on the above process, the obtained weight and threshold errors are used to train the network until the error on the test set meets the accuracy requirements. At this point, a dynamic compensation model is obtained, which achieves density compensation based on temperature and pressure.

[0065] The multi-parameter coupling rule is based on pv =nR T The relationship between density and temperature, pressure and liquid volume is calculated, and the various measurements of the final liquid mass are compensated and corrected to ensure the accuracy of the cumulative flow.

[0066] Finally, based on the actual conditions of the mass flow meters to be calibrated at the production site, multiple measurements were performed, and the obtained experimental data and original records were saved to the local database of the calibration system. A calibration certificate was generated based on the calibration results and the information from the mass flow meter log entered into the calibration system.

[0067] In one embodiment, the mass flow meter calibration device further includes a circulation pump. The inlet of the circulation pump is connected to the outlet 7, and the outlet of the circulation pump is connected to the inlet of the mass flow meter to be calibrated. By establishing a liquid circulation measurement system, the risk of liquid contamination caused by calibration is reduced, and the consumption of the measured liquid is reduced, saving costs. The circulation pump can also be connected to an intermediate buffer tank before being connected to the mass flow meter to be calibrated. By setting an intermediate buffer tank, it is easier to form a liquid loop and better realize the circulation of the medium liquid.

[0068] This embodiment also includes an online calibration method for a mass flow meter, comprising the following steps:

[0069] S1: Connect the inlet 5 of the mass flow meter calibration device to the fluid delivery pipeline;

[0070] S2: Initialize the calibration device, reset the calibration system, set the estimated instantaneous flow rate of the liquid, open the first valve 3 and the third valve 8, close the second valve 4, and the liquid flows through the mass flow meter to be calibrated, starting from the inlet 5;

[0071] S3: Adjust the liquid flow rate according to the site conditions and keep it stable. The second standard measuring instrument 2 will start measuring.

[0072] S4: The liquid level detection device 6 detects the liquid level in the second standard volumetric container 2. The temperature sensor and density meter start measuring. When the liquid level detection device 6 detects that the liquid level in the second standard volumetric container 2 has risen to the specified height, the pressure sensor starts measuring, the first valve 3 closes, the second valve 4 opens, the second standard volumetric container 2 is drained, and liquid continues to be injected into the first standard volumetric container 1. The calibration system records the first set of monitoring data.

[0073] S5: When the liquid level detection device 6 detects that the second standard volumetric 2 has finished draining, the second valve 4 is closed and the first valve 3 is opened, and the liquid flows from the first standard volumetric 1 into the second standard volumetric 2;

[0074] S6: Repeat steps S4 to S5 above until the test time ends, then close all valves and stop the injection.

[0075] S7: Based on the remaining liquid in the first standard volumetric instrument 1 and the second standard volumetric instrument 2, the last set of monitoring data is generated, and the calibration system optimizes and statistically analyzes each set of monitoring data.

[0076] S8: Obtain the cumulative mass flow rate value of the mass flow meter calibration device, compare it with the cumulative flow rate value measured by the mass flow meter to be calibrated, calculate the error, and realize the calibration of the mass flow meter to be calibrated.

[0077] In one embodiment, if it is not necessary to maintain the normal flow of fluid at the site during calibration, the mass flow meter calibration device also includes a circulation pump. Unlike the above embodiment, in step S1, the inlet of the circulation pump is connected to the outlet 7, and the outlet of the circulation pump is connected to the inlet of the mass flow meter to be calibrated. The liquid discharged from the second standard volumetric device 2 is returned to the mass flow meter calibration device for recycling through the circulation pump. By establishing a liquid circulation measurement system, the risk of liquid contamination caused by calibration is reduced, and the consumption of the measured liquid is reduced, saving costs.

[0078] The mass flow meter calibration device in this embodiment can cover the calibration range of 5t / h to 25t / h mass flow rate, and after testing, the accuracy level can be improved to 0.05.

[0079] It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0080] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A mass flow meter calibration device, characterized in that, include: A first standard measuring instrument and a second standard measuring instrument are provided. The first standard measuring instrument is positioned above the second standard measuring instrument and is connected to the second standard measuring instrument. A first valve is provided on the connecting pipe between the first and second standard measuring instruments. The second standard measuring instrument is provided with an outlet and a second valve. The first standard measuring instrument is provided with an inlet for connecting to the fluid delivery pipe of the mass flow meter to be calibrated and a third valve is provided on the inlet. Liquid level detection devices are provided inside both the first and second standard measuring instruments. Breathing valves for connecting to the outside are provided on both the first and second standard measuring instruments. The volume of the first standard measuring instrument is larger than the volume of the second standard measuring instrument. The second standard measuring instrument is equipped with a densitometer; both the first and second standard measuring instruments are equipped with a temperature sensor, a pressure sensor, and a transmitter. The online calibration method for this mass flow meter calibration device includes the following steps: S1: Connect the inlet of the mass flow meter calibration device to the fluid delivery pipeline; S2: Initialize the calibration device, reset the calibration system, set the estimated instantaneous flow rate of the liquid, open the first and third valves, close the second valve, and allow the liquid to flow through the mass flow meter to be calibrated, starting from the inlet. S3: Adjust the liquid flow rate according to the site conditions and keep it stable. The second standard measuring instrument will then begin measurement. S4: The liquid level detection device detects the liquid level in the second standard volumetric container. The temperature sensor and density meter start measuring. When the liquid level detection device detects that the liquid level in the second standard volumetric container has risen to the specified height, the pressure sensor starts measuring, the first valve closes, the second valve opens, the liquid is drained from the second standard volumetric container, and the liquid continues to be injected into the first standard volumetric container. The calibration system records the first set of monitoring data. S5: When the liquid level detection device detects that the second standard volumetric container has finished draining, the second valve closes and the first valve opens, and the liquid flows from the first standard volumetric container into the second standard volumetric container; S6: Repeat steps S4 to S5 above until the test time ends, then close all valves and stop the injection. S7: Based on the remaining liquid in the first and second standard measuring instruments, the last set of monitoring data is generated, and the calibration system optimizes and statistically analyzes each set of monitoring data. S8: Obtain the cumulative mass flow rate value of the mass flow meter calibration device, compare it with the cumulative flow rate value measured by the mass flow meter to be calibrated, calculate the error, and realize the calibration of the mass flow meter to be calibrated.

2. The mass flow meter calibration device according to claim 1, characterized in that, Both the first and second standard measuring instruments are provided with mounting brackets at their lower parts, and the mounting brackets are detachably connected to the first and second standard measuring instruments via snap-fit ​​connections.

3. The mass flow meter calibration device according to claim 1, characterized in that, The liquid level detection device, the first valve, and the second valve are all electrically connected to the control system.

4. The mass flow meter calibration device according to claim 1, characterized in that, The liquid level detection device is a high-precision liquid level gauge.

5. The mass flow meter calibration device according to claim 1, characterized in that, Both the first and second standard measuring instruments have funnel-shaped bottoms, and the lowest point of the first standard measuring instrument is connected to the top of the second standard measuring instrument through a connecting pipe.

6. The mass flow meter calibration device according to claim 1, characterized in that, The second standard measuring instrument is provided with a spiral flow guiding structure for optimizing the liquid flow pattern. The spiral flow guiding structure includes a flow guiding path. The starting end of the flow guiding path corresponds to the communication port between the second standard measuring instrument and the first standard measuring instrument, and the ending end of the flow guiding path extends to the side vertical plane of the second standard measuring instrument.

7. The mass flow meter calibration device according to claim 1, characterized in that, The mass flow meter calibration device also includes a circulation pump, the inlet of which is connected to the outlet, and the outlet of which is connected to the inlet of the mass flow meter to be calibrated.

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