Coriolis flowmeter zero point measuring device and zero point error compensation method
By designing an intelligent Coriolis flowmeter zero-point measurement device and error compensation method, and utilizing software control and algorithm correction, the problems of low efficiency and low accuracy in zero-point measurement in traditional methods are solved, achieving efficient and accurate zero-point error compensation.
Patent Information
- Application Number
- CN202511661762.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-13
- Publication Date
- 2026-02-17
AI Technical Summary
Traditional Coriolis flowmeters suffer from zero-point errors due to factors such as material properties, medium viscosity, temperature, and installation prestress at zero flow. Existing zero-point measurement methods are inefficient and inaccurate, failing to accurately acquire a stable zero point, thus affecting the flowmeter's metering performance.
A zero-point measurement device was designed, comprising a constant temperature water bath, a heater, an insulated tank, an iron stand, an electrically controlled ball valve, a Coriolis flow meter, a variable diameter ferrule, and a host computer. The device achieves automatic zero-point acquisition and error compensation through software control, and zero-point correction is performed using a fast sorting and median average filtering algorithm.
It improves zero-point measurement efficiency and accuracy, realizes intelligent, efficient and high-precision zero-point error compensation, reduces zero-point fluctuation and error accumulation, and enhances the metering performance of the flow meter.
Smart Images
Figure CN121540248A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of flow measurement technology, and particularly relates to a Coriolis flowmeter zero-point measuring device and a zero-point error compensation method. Background Technology
[0002] As a measuring instrument that can directly measure mass flow rate, the Coriolis mass flow meter has the advantages of high precision, high reliability, and wide measurement range, and has become an important instrument for mass flow measurement in modern industry.
[0003] The zero-point stability of a Coriolis flowmeter reflects its ability to measure zero flow. Ideally, its internal measuring tube vibrates in phase at zero flow, resulting in a zero phase difference acquired by the transmitter and correspondingly zero instantaneous flow. However, in actual operating conditions, factors such as the material properties of the measuring tube, the viscosity of the medium, temperature, and installation prestress cause the measuring tube to vibrate at different phases at zero flow. The internal sensor outputs a signal with a certain phase difference, leading to a non-zero instantaneous flow calculated by the transmitter, thus causing a zero-point error. If the zero point is not properly processed, it will... Errors can occur in the measured instantaneous and cumulative flow rates. Traditional methods for handling zero-point errors in Coriolis flowmeters mainly involve two approaches: one is zero-point optimization from the measurement circuit, which is the most direct and effective method, but it is costly and time-consuming; the other is zero-point cutoff by manually adjusting the transmitter, but the zero point will fluctuate within certain upper and lower limits. When manually zeroing, it may not be possible to accurately acquire a relatively stable zero point, which will still lead to the accumulation of zero-point errors, thus affecting the metering performance of the flowmeter. In addition, traditional zero-point measurement needs to be performed manually, which is also inefficient.
[0004] Therefore, developing an intelligent zero-point measurement device is of great significance for improving the accuracy of flow meter measurement and enhancing industrial production efficiency and quality. This device can accurately acquire the zero point by simply controlling the software during the periodic zero-point calibration of Coriolis flow meters, thereby compensating for zero-point errors and improving the flow meter measurement accuracy. Summary of the Invention
[0005] To address the shortcomings of the prior art, the present invention aims to provide a Coriolis flowmeter zero-point measuring device and a zero-point error compensation method.
[0006] The solution adopted by the present invention to solve its technical problem is as follows: The zero-point measuring device of the present invention includes a constant temperature water bath, a heater, a heat preservation tank, an iron stand, an electrically controlled ball valve, a Coriolis flow meter, a reducing sleeve, a pipe support frame, and a host computer.
[0007] The constant temperature water bath includes a PID temperature control system, a water bath cover, a water outlet, a water return outlet, a drain outlet, and heat dissipation holes. When performing zero-point measurement, the top cover of the water bath is opened, a medium is added to the constant temperature water bath, and the working temperature of the medium is set through the PID temperature control system to simulate the actual working environment. The water outlet and water return outlet of the constant temperature water bath are connected to an external measuring pipeline to form an external circulation. When the zero-point measurement is completed, the medium in the bath is quickly discharged through the drain outlet.
[0008] The heater is fixed by a clamp on an iron frame, and the heating tube is inserted into the heat preservation tank. The temperature set during operation is consistent with the temperature set in the constant temperature water bath, thereby compensating for the temperature loss generated by the medium during flow.
[0009] The insulated tank is placed on an iron stand. The upper surface of the insulated tank has an opening to ensure that the heating tube of the heater can be inserted into the tank, thereby controlling the temperature of the liquid inside the tank and establishing a second constant temperature field. The inlet of the insulated tank is connected to the outlet of the constant temperature water bath through a pipeline, and the outlet of the insulated tank is connected to the pipeline to draw out the medium.
[0010] The iron frame includes three parts: a support, a clamp, and a base. The clamp is fixed to the support by fastening bolts. The clamp fixes the heater so that the heating tube can be inserted into the heat preservation tank.
[0011] The so-called electrically controlled ball valve is divided into an upstream electrically controlled ball valve and a downstream electrically controlled ball valve. The upstream and downstream electrically controlled ball valves are connected to the upstream and downstream pipelines of the Coriolis flow meter via threads. They receive control commands from the host computer and switch the opening and closing of the pipeline to control the flow of liquid. The so-called electrically controlled ball valve is used to ensure that the liquid in the pipeline is in a static state when performing zero-point measurement.
[0012] The Coriolis flow meter consists of a Coriolis flow sensor and a transmitter, which are connected to the measuring pipeline by a thread. When performing zero-point measurement, it collects the flow rate value of the liquid in the pipeline and uploads the zero-point value to the host computer.
[0013] One end of the variable diameter ferrule is connected to the downstream electrically controlled ball valve, and the other end is connected to the return end of the constant temperature water tank, thereby completing the port adaptation of different pipe diameters in the device.
[0014] The aforementioned pipe support frame is installed on the pipe sections before and after the flow meter to ensure that the Coriolis flow meter can be fixed in the pipe and to reduce the impact of external environmental vibration on the Coriolis flow meter.
[0015] The host computer is connected to the upstream solenoid ball valve, downstream solenoid ball valve, heater, and Coriolis flow meter via physical cables. It mainly collects, stores, corrects zero-point error, and issues control commands for the measurement data of each module.
[0016] The detection principle of the Coriolis flowmeter zero-point measuring device is as follows: when the liquid fills the pipeline and remains in a flowing state, the host computer issues a command to first close the downstream solenoid ball valve, and after waiting for a period of time, close the upstream solenoid ball valve to ensure that the liquid is in a static state in the pipeline. At this time, the instantaneous flow value collected by the Coriolis flowmeter is the zero-point value under this working condition.
[0017] The method for improving the stability of the Coriolis flowmeter zero-point measurement device is as follows: the installation of the Coriolis flowmeter must ensure that it is coaxial with the connecting pipeline, and the pipeline connection parts are evenly stressed to reduce the stress between the flowmeter and the connecting pipelines before and after it, thereby improving the zero-point stability; a certain thickness of shock-absorbing rubber is added to the clamp of the pipeline support frame to reduce the impact of external environmental vibration on the flowmeter performance; before starting the zero-point measurement, all valves in the pipeline are opened to allow the medium to circulate, the working temperature of the medium is set through the constant temperature water bath, and after the temperature tends to stabilize, the medium flow rate is adjusted to 60% of the full capacity of the Coriolis flowmeter, and the pipeline is preheated for 20 minutes with the liquid filling the pipeline, so that the temperature of the measuring tube inside the flowmeter is consistent with the temperature of the medium before the zero-point measurement is performed, thereby improving the accuracy of the zero-point measurement under this working condition.
[0018] The Coriolis flow meter zero-point measurement method includes the following specific details:
[0019] 1) Before zero-point measurement: Set the working temperature and output flow rate of the medium through the constant temperature water bath; start the control program installed on the host computer and set the heater temperature to establish a second constant temperature field; start zero-point measurement when the temperature and flow rate are stable.
[0020] 2) Start zero-point measurement: Close the downstream solenoid ball valve of the pipeline through the host computer, wait for a period of time and then close the upstream solenoid ball valve of the pipeline to ensure that the liquid in the pipeline is not flowing and is in a static state. After the zero point stabilizes, collect the zero point value under this working condition from the Coriolis flow meter and save it.
[0021] 3) End zero-point measurement: The host computer issues a control command to open the electric ball valve to ensure the pipeline is unobstructed and the liquid in the pipeline flows back to the constant temperature water bath. Then, the external circulation function of the constant temperature water bath is turned off to prevent the liquid in the bath from flowing out. Furthermore, the heater and the constant temperature water bath are turned off, and the drain valve of the constant temperature water bath is opened to drain the liquid in the bath, thereby ending the zero-point measurement.
[0022] The principle of the Coriolis flowmeter zero-point error compensation method is as follows: When the zero point fluctuates slightly within a certain range, the host computer continuously collects N zero-point values according to the set sampling frequency f. These values are then sorted in ascending order using a quicksort algorithm. First, an array of length N is defined to store these N zero-point values. The first value is selected as the reference value. Elements greater than this value are placed to the right of the reference value, and elements less than this value are placed to the left of the reference value. Using this reference value as the boundary, the array is divided into two sub-sequences. Further, for the data in the left sub-array, a dividing value can be chosen to divide this data into left and right parts. Similarly, smaller values are placed on the left and larger values on the right. The same process is repeated for the right sub-array. Once the data in both the left and right sub-arrays are sorted, the entire array is sorted, thus completing the ascending order of these N zero-point values. At this point, the first element of the array is the minimum value Q. min The last element of the array is the maximum value Q. max Furthermore, a median average filtering algorithm is used to correct the zero point, and the maximum zero point value Q is adjusted. max and the minimum zero value Q min Remove from the array and calculate the average of the remaining N-2 zeros in the array. This filtering method can effectively suppress occasional impulse interference and eliminate the sampling value deviation caused by it, thus obtaining a more accurate zero point. Therefore, The corrected zero-point value Q0 is then saved to the host computer.
[0023] After obtaining the corrected zero point Q0 under this operating condition, the host computer can perform zero-point error correction on the instantaneous flow rate Q1 collected by the Coriolis flow meter. The corrected instantaneous flow rate Q'1 = Q1 ± Q0. In addition, it can also correct the cumulative flow rate Q collected by the Coriolis flow meter within the time period T. m Compensation is performed, and the corrected cumulative flow Q' m =Q m ±TQ0, this value is used as the compensated cumulative flow rate Q' m This method uses pure software to continuously collect and correct the zero-point value under the working condition in actual work, and save the corrected zero point. Furthermore, the flow rate measured by the Coriolis flowmeter can be zero-point error compensated based on the saved zero-point correction value Q0, without the need for manual adjustment of the transmitter to cut off the zero point, thereby realizing intelligent, high-efficiency, and high-precision zero-point acquisition and error compensation.
[0024] Compared with the prior art, the present invention has the following beneficial effects:
[0025] 1. The measuring device of the present invention improves the efficiency of zero-point measurement of Coriolis flow meters. Traditional Coriolis flow meter zero-point measurement requires manual adjustment of the opening and closing states of upstream and downstream valves to ensure the liquid in the pipeline is stationary before measuring the zero point. The measuring device of the present invention, however, can achieve rapid zero-point acquisition simply by operating the host computer software, eliminating the need for manual intervention and thus improving work efficiency.
[0026] 2. The zero-point error compensation method of this invention improves the measurement accuracy of zero point and flow rate of Coriolis flow meters. Traditional zero-point error correction requires operating the transmitter to cut off the zero point. However, the zero point of a Coriolis flow meter fluctuates within a certain range. This invention corrects the zero point based on a median average filtering algorithm, and compensates for errors in instantaneous flow rate and cumulative flow rate based on the compensated zero-point value. This avoids inaccurate zero adjustment and cumulative zero-point error caused by zero-point fluctuations, thereby improving measurement accuracy. Attached Figure Description
[0027] Figure 1 This is a side view of the Coriolis flowmeter zero-point measuring device of the present invention;
[0028] Figure 2 This is a side view of the constant temperature water bath in the measuring device of the present invention;
[0029] Figure 3 This is a side view of the heater in the measuring device of the present invention;
[0030] Figure 4 This is a side view of the insulated tank in the measuring device of the present invention;
[0031] Figure 5 This is a side view of the iron frame in the measuring device of the present invention;
[0032] Figure 6 This is a side view of the electrically controlled ball valve in the measuring device of the present invention;
[0033] Figure 7 This is a side view of the Coriolis flow meter in the measuring device of the present invention;
[0034] Figure 8 This is a side view of the pipe support frame in the measuring device of the present invention;
[0035] Figure 9 This is a flowchart of the Coriolis flowmeter zero-point error compensation method of the present invention;
[0036] In the diagram: 1. Constant temperature water bath; 1-1. PID temperature control system; 1-2. Water bath cover; 1-3. Water bath outlet; 1-4. Water bath return outlet; 1-5. Water bath drain outlet; 1-6. Heat dissipation hole; 2. Heater; 2-1. Heating tube; 3. Insulation tank; 3-1. Top opening of the water tank; 3-2. Water inlet of the insulation tank; 3-3. Water outlet of the insulation tank; 4. Iron frame; 4-1. Support; 4-2. Clamp; 4-3. Base; 5. Electric ball valve; 5-1. Upstream electric ball valve; 5-2. Downstream electric ball valve; 6. Coriolis flow meter; 6-1. Flow meter transmitter; 6-2. Flow sensor; 7. Variable diameter ferrule; 8. Pipe support frame; 8-1. Rubber pad; 8-2. Fastening bolt; 9. Host computer; Detailed Implementation
[0037] The present invention will be further described below with reference to the accompanying drawings.
[0038] like Figure 1 As shown, the zero-point measuring device in this invention includes a constant temperature water bath 1, a heater 2, a heat preservation tank 3, an iron stand 4, an electrically controlled ball valve 5, a Coriolis flow meter 6, a variable diameter ferrule 7, a pipe support frame 8, and a host computer 9.
[0039] like Figure 2 As shown, the constant temperature water bath 1 includes a PID temperature control system 1-1, a water bath cover 1-2, a water outlet 1-3, a water return outlet 1-4, a drain outlet 1-5, and heat dissipation holes 1-6. When performing zero-point measurement, the top cover 1-2 of the water bath 1 is opened, a medium is added to the constant temperature water bath 1, and the working temperature of the medium is set by the PID temperature control system 1-1 to simulate the actual working environment. The water outlet 1-3 and the water return outlet 1-4 of the constant temperature water bath 1 are connected to an external measuring pipeline to form an external circulation. When the zero-point measurement is completed, the medium in the bath is quickly discharged through the drain outlet 1-5.
[0040] like Figure 3 As shown, the heater 2 is fixed by the clamp 4-2 on the iron frame 4, and the heating tube 2-1 is inserted into the heat preservation tank 3. The temperature set during operation is consistent with the temperature set in the constant temperature water bath 1, thereby compensating for the temperature loss generated by the medium during the flow process.
[0041] like Figure 4 As shown, the heat preservation tank 3 is placed on the iron stand 4. The upper surface of the heat preservation tank 3 has an opening to ensure that the heating tube 2-1 of the heater 2 can be inserted into the tank, thereby controlling the temperature of the liquid and establishing a second constant temperature field. The water inlet 3-2 of the heat preservation tank 3 is connected to the water outlet 1-3 of the constant temperature water bath through a pipeline. The water outlet 3-3 of the heat preservation tank 3 is connected to the pipeline to draw out the medium.
[0042] like Figure 5As shown, the iron frame 4 includes three parts: a support 4-1, a clamp 4-2, and a base 4-3. The clamp 4-2 is fixed to the support 4-1 by fastening bolts. The clamp 4-2 fixes the heater 2 so that the heating tube 2-1 can be inserted into the heat preservation tank 3.
[0043] like Figure 6 As shown, the electrically controlled ball valve 5 is divided into an upstream electrically controlled ball valve 5-1 and a downstream electrically controlled ball valve 5-2. The upstream electrically controlled ball valve 5-1 and the downstream electrically controlled ball valve 5-2 are connected to the upstream and downstream pipelines of the Coriolis flow meter 6 via threads. They receive control commands from the host computer 9 and switch the opening and closing of the pipeline to control the flow of liquid. When performing zero-point measurement, the electrically controlled ball valve 5 is used to ensure that the liquid in the pipeline is in a static state.
[0044] like Figure 7 As shown, the Coriolis flow meter 6 consists of a transmitter 6-1 and a Coriolis flow sensor 6-2, which are connected to the measuring pipeline by threads. When performing zero-point measurement, it collects the flow rate value of the liquid in the pipeline and uploads the zero value to the host computer 9.
[0045] like Figure 8 As shown, the pipeline support frame 8 is installed on the pipe sections before and after the flow meter 6 to ensure that the Coriolis flow meter 6 can be fixed in the pipeline and to reduce the impact of external environmental vibration on the Coriolis flow meter 6.
[0046] The Coriolis flow meter zero-point measuring device described above has the following detection principle: when the liquid fills the pipeline and remains in a flowing state, the host computer 9 issues a command to first close the downstream solenoid ball valve 5-2, and after waiting for a period of time, close the upstream solenoid ball valve 5-1 to ensure that the liquid is in a static state in the pipeline. At this time, the instantaneous flow value collected by the Coriolis flow meter 6 is the zero-point value under this working condition.
[0047] The method for improving the stability of the Coriolis flowmeter zero-point measuring device is as follows:
[0048] Method 1: The installation of the Coriolis flow meter 6 should ensure that it is coaxial with the connecting pipeline, and apply force evenly to the pipeline connection parts to reduce the stress between the flow meter 6 and the connecting pipelines before and after it, thereby improving the zero-point stability.
[0049] Method 2: A certain thickness of shock-absorbing rubber 8-1 is added inside the clamp of the pipe support frame 8 to reduce the impact of external environmental vibration on the performance of the flow meter 6.
[0050] Method 3: Before starting the zero-point measurement, open all valves in the pipeline to allow the medium to circulate. Set the working temperature of the medium through the constant temperature water bath 1. After the temperature stabilizes, adjust the medium flow rate to 60% of the full scale of the Coriolis flow meter 6. Preheat the pipeline for 20 minutes with the liquid filling it, and then perform the zero-point measurement when the temperature of the measuring tube inside the flow meter 6 is consistent with the temperature of the medium. This will improve the accuracy of the zero-point measurement under this working condition.
[0051] The steps of the Coriolis flowmeter 6 zero-point measuring device are as follows:
[0052] Step 1, before zero-point measurement: Set the working temperature and output flow rate of the medium through the constant temperature water bath 1; start the control program installed on the host computer 9 and set the temperature of the heater 2 to establish a second constant temperature field; start zero-point measurement when the temperature and flow rate are stable.
[0053] Step 2: Start zero-point measurement: Close the downstream solenoid ball valve 5-2 of the pipeline through the host computer 9, wait for a period of time, and then close the upstream solenoid ball valve 5-1 of the pipeline to ensure that the liquid in the pipeline is not flowing and is in a static state. After the zero point stabilizes, collect the zero point value under this working condition from the Coriolis flow meter 6 and save it.
[0054] Step 3: End Zero-Point Measurement: The host computer 9 issues a control command to open the electric ball valve 5 to ensure the pipeline is unobstructed and to return the liquid in the pipeline to the constant temperature water bath 1. Then, the external circulation function of the constant temperature water bath 1 is turned off to prevent the liquid in the bath from flowing out. Furthermore, the heater 2 and the constant temperature water bath 1 are turned off, and the drain valves 1-5 of the constant temperature water bath 1 are opened to drain the liquid in the bath, thereby ending the zero-point measurement.
[0055] like Figure 9 As shown, the zero-point error compensation principle of the Coriolis flowmeter 6 is as follows: When the zero point fluctuates slightly within a certain range, the host computer 9 continuously collects N zero-point values according to the set sampling frequency f. These values are then sorted in ascending order using a quicksort algorithm. First, an array of length N is defined to store these N zero-point values. The first value is selected as the reference value. Elements greater than this value are placed to the right of the reference value, and elements less than this value are placed to the left of the reference value. Using this reference value as the boundary, the array is divided into two sub-sequences. Further, for the data in the left sub-array, a dividing value can be taken to divide this data into left and right parts. Similarly, smaller values are placed on the left and larger values on the right. The same process is repeated for the right sub-array. Once the data in both the left and right sub-arrays are sorted, the entire array is sorted, thus completing the ascending order of these N zero-point values. At this point, the first element of the array is the minimum value Q. min The last element of the array is the maximum value Q.max Furthermore, a median average filtering algorithm is used to correct the zero point, and the maximum zero point value Q is adjusted. max and the minimum zero value Q min Remove from the array and calculate the average of the remaining N-2 zeros in the array. This filtering method can effectively suppress occasional impulse interference and eliminate the sampling value deviation caused by it, thus obtaining a more accurate zero point. Therefore, The corrected zero-point value Q0 is then saved to the host computer 9.
[0056] After obtaining the corrected zero point Q0 under this operating condition, the host computer 9 can perform zero-point error correction on the instantaneous flow rate Q1 collected by the Coriolis flow meter 6. The corrected instantaneous flow rate Q'1 = Q1 ± Q0. In addition, it can also correct the cumulative flow rate Q collected by the Coriolis flow meter 6 within the time period T. m Compensation is performed, and the corrected cumulative flow Q' m =Q m ±TQ0, this value is used as the compensated cumulative flow rate Q' m This method uses pure software to continuously collect and correct the zero-point value under the working condition in actual work, and save the corrected zero point. Furthermore, the flow rate measured by the Coriolis flowmeter 6 can be used to compensate for the zero-point error of the measurement result based on the saved zero-point correction value, without the need for manual adjustment of the transmitter 6-1 for zero-point cutoff, thereby realizing intelligent, high-efficiency, and high-precision zero-point acquisition and error compensation.
[0057] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.
Claims
1. The zero-point measuring device of the Coriolis flowmeter is characterized by: Includes constant temperature water bath, heater, insulated tank, iron frame, electrically controlled ball valve, Coriolis flow meter, reducing sleeve, pipe support frame, and host computer; The constant temperature water bath includes a PID temperature control system, a water bath cover, a water outlet, a water return outlet, a drain outlet, and heat dissipation holes. When performing zero-point measurement, the top cover of the water bath is opened, a medium is added to the constant temperature water bath, and the working temperature of the medium is set through the PID temperature control system to simulate the actual working environment. The water outlet and water return outlet of the constant temperature water bath are connected to an external measuring pipeline to form an external circulation. When the zero-point measurement is completed, the medium in the bath is quickly discharged through the drain outlet. The heater is fixed by a clamp on an iron frame, and the heating tube is inserted into the heat preservation tank. The temperature set during operation is consistent with the temperature set in the constant temperature water bath, thereby compensating for the temperature loss generated by the medium during flow. The insulated tank is placed on an iron stand. The upper surface of the insulated tank has an opening to ensure that the heating tube of the heater can be inserted into the tank, thereby controlling the temperature of the liquid inside the tank and establishing a second constant temperature field. The inlet of the insulated tank is connected to the outlet of the constant temperature water bath through a pipeline, and the outlet of the insulated tank is connected to the pipeline to draw out the medium. The iron frame includes three parts: a support, a clamp, and a base. The clamp is fixed to the support by fastening bolts. The clamp fixes the heater so that the heating tube can be inserted into the heat preservation tank. The so-called electrically controlled ball valve is divided into an upstream electrically controlled ball valve and a downstream electrically controlled ball valve. The upstream and downstream electrically controlled ball valves are connected to the upstream and downstream pipelines of the Coriolis flow meter via threads. They receive control commands from the host computer and switch the opening and closing of the pipeline to control the flow of liquid. The so-called electrically controlled ball valve is used to ensure that the liquid in the pipeline is in a static state when performing zero-point measurement. The Coriolis flow meter consists of a transmitter and a Coriolis flow sensor, which are connected to the measuring pipeline by threads. When performing zero-point measurement, it collects the flow rate value of the liquid in the pipeline and uploads the zero value to the host computer. One end of the variable diameter ferrule is connected to the downstream electrically controlled ball valve, and the other end is connected to the return end of the constant temperature water tank, thereby completing the port adaptation of different pipe diameters in the device. The aforementioned pipe support frame is installed on the pipe sections before and after the flow meter to ensure that the Coriolis flow meter can be fixed in the pipe and to reduce the impact of external environmental vibration on the Coriolis flow meter. The host computer is connected to the upstream and downstream electrically controlled ball valves, heaters, and Coriolis flow meters via physical cables. It mainly collects, stores, corrects zero-point errors, and issues control commands to each module.
2. The detection principle of the Coriolis flowmeter zero-point measuring device, using the device according to claim 1, is characterized in that: When the liquid fills the pipeline and remains in a flowing state, the host computer issues a command to first close the downstream solenoid ball valve, and then close the upstream solenoid ball valve after a period of time to ensure that the liquid is in a static state in the pipeline. At this time, the instantaneous flow rate value collected by the Coriolis flow meter is the zero point value under this working condition.
3. A method for improving the stability of a Coriolis flowmeter zero-point measuring device, using the device according to claim 1, characterized in that: The installation of the Coriolis flow meter should ensure that it is coaxial with the connecting pipeline, and apply force evenly to the pipeline connection parts to reduce the stress between the flow meter and the connecting pipelines before and after it, thereby improving zero-point stability. The pipe support frame has a clamp with a certain thickness of shock-absorbing rubber inside, thereby reducing the impact of external environmental vibration on the flow meter performance. Before starting the zero-point measurement, open all valves in the pipeline to allow the medium to circulate. Set the working temperature of the medium using the constant temperature water bath. Once the temperature stabilizes, adjust the medium flow rate to 60% of the full capacity of the Coriolis flowmeter. Preheat the pipeline for 20 minutes with the liquid filling it, ensuring that the temperature of the measuring tube inside the flowmeter matches the temperature of the medium before performing the zero-point measurement. This improves the accuracy of the zero-point measurement under these conditions.
4. A method for measuring the zero point of a Coriolis flowmeter, using the device according to claim 1 and the measurement principle according to claim 2, characterized in that: 1) Before zero-point measurement: Set the working temperature and output flow rate of the medium through the constant temperature water bath; start the control program installed on the host computer and set the heater temperature to establish a second constant temperature field; start zero-point measurement when the temperature and flow rate are stable. 2) Start zero-point measurement: Close the downstream solenoid ball valve of the pipeline through the host computer, wait for a period of time and then close the upstream solenoid ball valve of the pipeline to ensure that the liquid in the pipeline is not flowing and is in a static state. After the zero point stabilizes, collect the zero point value under this working condition from the Coriolis flow meter and save it. 3) End zero-point measurement: The host computer issues a control command to open the electric ball valve, so that the pipeline is unobstructed and the liquid in the pipeline flows back to the constant temperature water bath. Then, the external circulation function of the constant temperature water bath is turned off, so that the liquid in the bath no longer flows out. Furthermore, the heater and the constant temperature water bath are turned off, and the drain valve of the constant temperature water bath is opened to drain the liquid in the bath, thereby ending the zero-point measurement.
5. A method for zero-point error compensation of a Coriolis flowmeter, using the zero-point measurement method according to claim 3, characterized in that: When the zero point fluctuates slightly within a certain range, the host computer continuously collects N zero-point values according to the set sampling frequency f. These N zero-point values are then sorted in ascending order using a quicksort algorithm. First, an array of length N is defined to store these N zero-point values. The first value is selected as the pivot value. Elements greater than this value are placed to the right of the pivot value, and elements less than this value are placed to the left of the pivot value. Using this pivot value as the boundary, the array is divided into two subsequences. Further, for the data in the left subsequence, a dividing value can be chosen to divide this data into left and right parts. Similarly, smaller values are placed on the left and larger values on the right. The same process is repeated for the right subsequence. Once the data in both the left and right subsequences are sorted, the entire array is sorted, thus completing the ascending order of these N zero-point values. At this point, the first element of the array is the minimum value Q. min The last element of the array is the maximum value Q. max Furthermore, a median average filtering algorithm is used to correct the zero point, and the maximum zero point value Q is adjusted. max and the minimum zero value Q min Remove from the array and calculate the average of the remaining N-2 zeros in the array. This filtering method can effectively suppress occasional impulse interference and eliminate the sampling value deviation caused by it, thus obtaining a more accurate zero point. Therefore, The corrected zero-point value Q0 is then saved to the host computer. After obtaining the corrected zero point Q0 under this operating condition, the host computer can perform zero-point error correction on the instantaneous flow rate Q1 collected by the Coriolis flow meter. The corrected instantaneous flow rate Q'1 = Q1 ± Q0. In addition, it can also correct the cumulative flow rate Q collected by the Coriolis flow meter within the time period T. m Compensation is performed, and the corrected cumulative flow Q' m =Q m ±TQ0, this value is used as the compensated cumulative flow rate Q' m This method uses pure software to continuously collect and correct the zero-point value under the working condition in actual work, and save the corrected zero point. Furthermore, the flow rate measured by the Coriolis flowmeter can be zero-point error compensated based on the saved zero-point correction value Q0, without the need for manual adjustment of the transmitter to cut off the zero point, thereby realizing intelligent, high-efficiency, and high-precision zero-point acquisition and error compensation.