A method for screening abnormal sound channels of a four-channel gas ultrasonic flowmeter

Abstract

The present application relates to the technical field of gas metering, in particular to a sound channel abnormality screening method of a four-sound-channel gas ultrasonic flowmeter. The sound channel abnormality jump wave is divided into sound velocity judgment condition and flow velocity judgment condition, and the corresponding reference standard is determined for each condition as the basis for verifying and calibrating the sound channel metering misalignment, which provides a more reliable reference for the abnormality screening of the sound channel, and considers the sound velocity and flow velocity to judge whether the sound channel has jump wave. The sound velocity judgment based on the corresponding reference standard and the absolute value of the sound velocity difference between the sound channels can effectively screen out abnormal sound channels. If no jump wave sound channel is found, the flow velocity judgment based on the corresponding reference standard and the absolute value of the flow velocity difference between the sound channels is further performed, which realizes more comprehensive and accurate screening of abnormal jump wave sound channels, thereby providing a basis for eliminating abnormal sound channel data caused by jump wave.

Description

Technical Field

[0001] This invention relates to the field of gas metering technology, specifically to a method for screening channel anomalies in a four-channel ultrasonic gas flow meter. Background Technology

[0002] A four-channel ultrasonic gas flow meter is an instrument used to measure gas flow rate. It determines the gas flow rate by measuring the difference in sound velocity during gas flow using ultrasonic technology. This type of flow meter typically consists of four channels: two channels for transmitting ultrasonic signals and two channels for receiving them. When an ultrasonic signal is transmitted from one channel to another, the difference in sound velocity causes a change in signal propagation time. By measuring this change in propagation time, the gas flow velocity and flow rate can be calculated. Due to its high accuracy, wide measurement range, and good stability, the four-channel design has gradually become the mainstream design approach for ultrasonic gas flow meters and is widely used in industrial applications requiring accurate gas flow measurement, such as petrochemical, power, and metallurgical industries.

[0003] However, the increase in the number of channels inevitably leads to the technical problem of difficulty in identifying and eliminating data from a channel when a measurement error occurs in one of the channels of a four-channel ultrasonic gas flow meter. Furthermore, a common cause of measurement error in the four-channel ultrasonic gas flow meter is skipping waves, which cause the flight time to shift forward or backward, thus having a regular impact on the measurement characteristic data (i.e., sound velocity and flow velocity) of the four-channel ultrasonic gas flow meter. Skip waves refer to the phenomenon where, when an ultrasonic signal propagates from a transmitting channel to a receiving channel, the signal partially or completely skips the receiving channel during propagation and is not properly received. This can be caused by obstacles in the signal propagation path, turbulence in the gas flow, signal attenuation, etc. Time of flight refers to the time required for an ultrasonic signal to travel from one channel to another. However, in the current technology, there is still a lack of reliable reference standards and screening methods to verify and calibrate whether measurement errors exist in each channel of a four-channel ultrasonic gas flow meter. Summary of the Invention

[0004] The technical problem to be solved by this invention is that current four-channel ultrasonic gas flow meters have the technical problem of difficulty in identifying and eliminating channel data with measurement inaccuracies. This invention proposes a channel anomaly screening method for four-channel ultrasonic gas flow meters, aiming to provide a more reliable reference standard and screening method to verify and calibrate whether there are measurement inaccuracies in each channel of the four-channel ultrasonic gas flow meter.

[0005] This invention adopts the following technical solution: a method for screening channel anomalies in a four-channel ultrasonic gas flow meter, comprising the following steps:

[0006] List all cases of wave jumping in the current channel under forward / backward flow conditions, and divide all cases of wave jumping in the current channel under forward / backward flow conditions into sound velocity judgment cases and flow velocity judgment cases;

[0007] In the case of sound velocity determination, the sound velocity measurement error of the current channel is calculated in each case, and a first reference standard is determined based on the sound velocity measurement error of the current channel in each case.

[0008] Calculate the absolute value of the sound velocity difference between each channel;

[0009] Based on the first reference standard and the absolute value of the sound velocity difference between each channel, determine whether wave skipping occurs in each channel. If no wave skipping occurs in any of the four channels, proceed to the next step:

[0010] In the flow rate determination case, the flow rate measurement error of the current channel is calculated in each case, and a second reference standard is determined based on the flow rate measurement error of the current channel in each case;

[0011] The flow velocity of each channel is standardized to obtain the flow velocity of each channel at the axis of the flow meter;

[0012] Calculate the absolute value of the velocity difference between each channel based on the flow velocity of each channel at the axis of the flow meter.

[0013] Based on the second reference standard and the absolute value of the flow rate difference between each channel, it is determined whether wave skipping occurs in each channel.

[0014] Wherein, the first reference standard represents a reference standard determined in the case of sound velocity judgment for determining whether wave skipping occurs in the sound channel. The second reference standard represents a reference standard determined in the case of flow velocity judgment for determining whether wave skipping occurs in the sound channel.

[0015] The technical concept of this invention is as follows: First, all cases of wave skipping in the current channel under forward / backward flow are listed, and these cases are divided into sound velocity judgment cases and flow velocity judgment cases. A first reference standard is determined based on the sound velocity measurement error of the current channel under the sound velocity judgment case, and a second reference standard is determined based on the flow velocity measurement error of the current channel under the flow velocity judgment case. Second, sound velocity judgment is performed first, that is, based on the first reference standard and the absolute value of the sound velocity difference between each channel, it is determined whether each channel has wave skipping, and anomaly screening of each channel is performed. Next, if no wave skipping channel is found through the above sound velocity judgment, flow velocity judgment is performed next, that is, based on the second reference standard and the absolute value of the flow velocity difference between each channel, it is determined whether each channel has wave skipping, so as to complete the final channel anomaly screening.

[0016] By categorizing all cases of abnormal channel skipping into sound velocity judgment and flow velocity judgment, and establishing corresponding reference standards for each category, these reference standards serve as the basis for verifying and calibrating channel measurement inaccuracies, providing a relatively reliable reference for screening abnormal channels. Simultaneously, both sound velocity and flow velocity are considered in determining whether channel skipping has occurred. By first performing sound velocity judgment based on the corresponding reference standards and the absolute value of the sound velocity difference between each channel, abnormal channels can be effectively screened. If no skipping channels are found, further flow velocity judgment is performed based on the corresponding reference standards and the absolute value of the flow velocity difference between each channel, achieving a more comprehensive and accurate screening of abnormal skipping channels. This provides a foundation for eliminating abnormal channel data caused by skipping, thereby ensuring the measurement accuracy and reliability of the four-channel ultrasonic gas flow meter.

[0017] As a preferred method, the method for classifying all cases of wave jumping in the current channel under forward / backward flow conditions into sound velocity judgment cases and flow velocity judgment cases includes:

[0018] Calculate the theoretical values ​​of sound velocity and flow velocity for the current channel under all conditions;

[0019] Obtain the measured sound velocity and actual flow velocity of the current channel under all conditions;

[0020] Based on the difference between the theoretical and measured sound velocity values ​​of the current channel and the difference between the theoretical and actual flow velocity values, all cases of wave jumping in the current channel under forward / backward flow are divided into sound velocity judgment cases and flow velocity judgment cases.

[0021] As a preferred method, based on the difference between the theoretical and measured sound velocity values ​​of the current channel and the difference between the theoretical and actual flow velocity values, the method for classifying all cases of wave jumping in the current channel under both forward and reverse flow conditions into sound velocity-based cases and flow velocity-based cases includes:

[0022] If the difference between the theoretical and measured sound velocity values ​​of the current channel exceeds the first preset threshold, then the case of wave jumping in the current channel under forward / backward flow is classified into the sound velocity judgment case. If the difference between the theoretical and measured sound velocity values ​​of the current channel does not exceed the first preset threshold, then the case of wave jumping in the current channel under forward / backward flow is not processed.

[0023] If the difference between the theoretical and actual flow rates of the current channel exceeds the second preset threshold, then the case of wave skipping in the current channel under forward / backward flow will be classified as a flow rate judgment case. If the difference between the theoretical and actual flow rates of the current channel does not exceed the second preset threshold, then the case of wave skipping in the current channel under forward / backward flow will not be processed.

[0024] As a preferred method, the method for determining the first reference standard based on the sound velocity measurement error of the current channel under various conditions includes:

[0025] The minimum sound velocity measurement error of the current channel under each sound velocity judgment condition is selected as the first reference standard.

[0026] As a preferred method, the absolute value of the sound velocity difference between each channel includes:

[0027] Obtain the measured sound velocity value for each channel;

[0028] Calculate the absolute value of the difference between the measured sound velocity values ​​of each channel to obtain the absolute value of the sound velocity difference between each channel.

[0029] As a preferred method, based on a first reference standard and the absolute value of the sound velocity difference between each channel, the method for determining whether wave skipping occurs in each channel includes:

[0030] Select one channel and compare the absolute value of the sound velocity difference between the current channel and other channels with the first reference standard. If there are two or more absolute values ​​of the sound velocity difference between the current channel and other channels that are greater than the first reference standard, it is determined that the current channel has a wave skipping problem. If not, repeat the above steps for the next channel until all four channels have been compared.

[0031] As a preferred method, the method for determining the second reference standard based on the flow velocity measurement error of the current channel under various conditions includes:

[0032] The minimum value among the flow rate measurement errors of the current channel under each flow rate judgment condition is selected as the second reference standard.

[0033] As a preferred method, the flow velocity of each channel is standardized to obtain the flow velocity of each channel at the axis of the flowmeter, including:

[0034] Obtain the actual flow rate values ​​for the four audio channels;

[0035] The four channels are divided into channels near the tube wall and channels near the axis.

[0036] The quotient of the actual flow velocity of the channel near the pipe wall and the first preset coefficient is taken as the flow velocity of the channel near the pipe wall at the axis of the flowmeter. The quotient of the actual flow velocity of the channel near the axis and the second preset coefficient is taken as the flow velocity of the channel near the axis at the axis of the flowmeter.

[0037] As a preferred method, the method for calculating the absolute value of the velocity difference between channels based on the flow velocity of each channel at the axis of the flow meter includes:

[0038] Calculate the absolute value of the difference between the flow velocities of each channel at the axis of the flow meter to obtain the absolute value of the flow velocity difference between each channel.

[0039] As a preferred method, based on a second reference standard and the absolute value of the flow rate difference between each channel, the method for determining whether wave skipping occurs in each channel includes:

[0040] Select one channel and compare the absolute value of the flow rate difference between the current channel and other channels with the second reference standard. If there are two or more absolute values ​​of the flow rate difference between the current channel and other channels that are greater than the second reference standard, it is determined that the current channel has a wave skipping problem. If not, repeat the above steps for the next channel until all four channels have been compared.

[0041] The beneficial technical effects of this invention include at least the following: A method for screening channel anomalies in a four-channel ultrasonic gas flow meter is employed. This method categorizes all cases of channel anomaly jumping into sound velocity judgment and flow velocity judgment, and establishes corresponding reference standards for each category. These reference standards serve as the basis for verifying and calibrating channel measurement inaccuracies, providing a relatively reliable reference for channel anomaly screening. Simultaneously, both sound velocity and flow velocity are considered in determining whether channel jumping has occurred. By first performing sound velocity judgment based on the corresponding reference standards and the absolute value of the sound velocity difference between each channel, abnormal channels can be effectively screened. If no jumping channels are found, further flow velocity judgment is performed based on the corresponding reference standards and the absolute value of the flow velocity difference between each channel. This achieves a more comprehensive and accurate screening of abnormal jumping channels, thus providing a basis for eliminating abnormal channel data caused by jumping, and ultimately ensuring the measurement accuracy and reliability of the four-channel ultrasonic gas flow meter.

[0042] Other features and advantages of the present invention will be disclosed in detail in the following detailed description and accompanying drawings. Attached Figure Description

[0043] The invention will be further described below with reference to the accompanying drawings:

[0044] Figure 1 This is a flowchart of the channel anomaly screening method for a four-channel ultrasonic gas flow meter according to an embodiment of the present invention.

[0045] Figure 2 This is a flowchart illustrating the classification method for determining sound velocity and flow velocity according to an embodiment of the present invention. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be explained and described below with reference to the accompanying drawings. However, the following embodiments are only preferred embodiments of the present invention and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments in the implementation methods without creative effort are all within the protection scope of the present invention.

[0047] In the following description, terms such as “inner,” “outer,” “upper,” “lower,” “left,” and “right” are used only to indicate orientation or positional relationship for the convenience of describing the embodiments and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0048] This application provides a method for screening channel anomalies in a four-channel ultrasonic gas flow meter. Please refer to the appendix. Figure 1 This includes the following steps:

[0049] Step 101: List all cases of wave jumping in the current channel under forward / backward flow, and divide all cases of wave jumping in the current channel under forward / backward flow into sound velocity judgment cases and flow velocity judgment cases.

[0050] Specifically, taking the data of a certain channel of a four-channel ultrasonic gas flow meter in air as an example, the speed of sound in air is 340 m / s, the length of the channel is L = 100.23 mm, and the diameter is D = 96 mm. The following eight situations are all possible for the current channel to produce wave skipping under both forward and reverse flow:

[0051] Scenario 1: Jumping forward in one wave simultaneously with and against the current, according to the formula... The measured value of the speed of sound is calculated, where, C is the measured sound speed, L is the theoretical sound speed (in m / s), f is the frequency of the ultrasonic echo signal (in Hz), and θ is the channel angle (i.e., the angle between the channel and the axis). In this case, the measured sound speed is larger than the theoretical sound speed. The specific parameters for case one are shown in Table 1.

[0052]

[0053] Table 1 Specific parameters for Case 1

[0054] Scenario 2: A wave jumps backward simultaneously with both upstream and downstream currents. In this case, the measured value of the sound speed is smaller than the theoretical value of the sound speed. The specific parameters of Scenario 2 are shown in Table 2.

[0055]

[0056] Table 2 Specific parameters for Case 2

[0057] Scenario 3: Jumping one wave forward with the current and one wave backward against the current, the difference between the measured and theoretical values ​​of sound speed is not significant, but the time difference between the forward and reverse currents is large. At all flow points, the time difference Δt was increased by two cycles compared to the normal time, resulting in the actual flow velocity being much larger than the theoretical flow velocity. The specific parameters for case three are shown in Table 3.

[0058]

[0059] Table 3 Specific parameters for Case 3

[0060] Scenario 4: Jumping one wave backward with the current and one wave forward against the current, the difference between the measured and theoretical sound speeds is not significant, but the time difference between the upstream and downstream directions is large. At all flow points, the time difference Δt was reduced by two cycles compared to the normal time, and the flow velocity was much smaller than the theoretical value, even showing a negative value. The specific parameters for case four are shown in Table 4.

[0061]

[0062] Table 4 Specific parameters for Case 4

[0063] Case 5: When the downstream current remains unchanged, but the upstream current jumps one wave backward, the measured value of the sound speed is smaller than the theoretical value. The specific parameters for case 5 are shown in Table 5.

[0064]

[0065] Table 5 Specific parameters for Case 5

[0066] Case 6: When the downstream current remains unchanged, but the sound jumps forward one wave against the current, the measured value of the sound speed is larger than the theoretical value. The specific parameters of Case 6 are shown in Table 6.

[0067]

[0068] Table 6 Specific parameters for Case Six

[0069] Case 7: A wave jumps forward with the current, while there is no wave jump in the countercurrent. In this case, the measured value of the speed of sound is larger than the theoretical value. The specific parameters of Case 7 are shown in Table 7.

[0070]

[0071] Table 7 Specific parameters for Case 7

[0072] Case 8: A wave jumps backward with the current, while there is no wave jump with the current. In this case, the measured value of the sound speed is smaller than the theoretical value of the sound speed. The specific parameters of Case 8 are shown in Table 8.

[0073]

[0074] Table 8 Specific parameters for Case 8

[0075] Optionally, in addition to using the difference between the theoretical and measured sound velocity values ​​and the difference between the theoretical and actual flow velocity values ​​of the current channel, the implementation of dividing all eight cases of wave jumping in the current channel under forward / backward flow conditions into sound velocity judgment and flow velocity judgment can also be carried out in the following ways, which are not limited in this embodiment:

[0076] 1. Sound speed change judgment: The occurrence of wave jumping is determined by monitoring changes in sound speed. Temperature sensors or other methods can be used to measure the gas temperature. The relationship between sound speed and temperature is then used to determine if a change in sound speed has occurred. If the change in sound speed exceeds a certain threshold, the current situation can be categorized as a sound speed judgment situation; if the change in sound speed does not exceed a certain threshold, the current situation can be categorized as a flow velocity judgment situation.

[0077] 2. Sound path difference judgment: The sound path difference between different channels is compared to determine whether wave skipping has occurred. If the difference between the sound path difference and the expected value exceeds a certain threshold, the current situation can be classified as a sound velocity judgment case. If the difference between the sound path difference and the expected value does not exceed a certain threshold, the current situation can be classified as a flow velocity judgment case.

[0078] Step 102: In the case of sound velocity determination, calculate the sound velocity measurement error of the current channel in each case, and determine the first reference standard based on the sound velocity measurement error of the current channel in each case.

[0079] Among them, the sound velocity measurement error refers to the absolute value of the difference between the measured sound velocity and the theoretical sound velocity value. It is used to evaluate the accuracy and precision of sound velocity measurement and reflects the gap between the measurement result and the true value. The first reference standard refers to a reference standard determined in the sound velocity judgment situation for judging whether wave skipping occurs in the sound channel.

[0080] Optionally, the method for determining the first reference standard based on the sound velocity measurement error of the current channel under each condition may be to select the minimum value of the sound velocity measurement error of the current channel under each condition as the first reference standard, or to select the average value, median, etc. of the sound velocity measurement error of the current channel under each condition as the first reference standard. This embodiment does not limit this.

[0081] Step 103: Calculate the absolute value of the sound velocity difference between each channel.

[0082] Here, the sound velocity refers only to the measured value, not the theoretical value. The theoretical sound velocity is a predicted value calculated based on fluid properties (such as density, pressure, and temperature) and pipe geometry; it is a result of calculations based on a theoretical model. Variations in the theoretical sound velocity are usually related to the fluid's properties or the flow meter's operating conditions, such as changes in fluid temperature or pressure. While forward / backward flow may affect the fluid's flow characteristics, it typically does not cause jumps in the theoretical sound velocity value.

[0083] Optionally, the absolute value of the sound velocity difference between each channel can be calculated using the following method in this embodiment, which is not limited in this embodiment:

[0084] 1. Calculate the absolute value of the difference between the measured sound velocity values ​​of each channel.

[0085] 2. Calculation based on sound velocity propagation models: Sound velocity propagation models can be used to calculate the sound velocity difference between different sound channels. These models can be based on fluid properties (such as density, pressure, temperature, etc.) and pipe geometry. The sound velocity difference calculated by the model can be used as a reference value for analysis and comparison.

[0086] 3. Method based on sound velocity correction factor: Some flow meter devices provide sound velocity correction factors to correct the influence of sound velocity on flow velocity measurement. These correction factors can be calculated based on specific fluid and flow meter designs. By applying the appropriate correction factor, the corrected sound velocity value can be obtained, and then the absolute value of the sound velocity difference between each channel can be calculated.

[0087] Step 104: Based on the first reference standard and the absolute value of the sound velocity difference between each channel, determine whether each channel has a wave skipping event. If no wave skipping event occurs in any of the four channels, proceed to the next step.

[0088] Optionally, in this embodiment, the method of determining whether each channel has experienced wave skipping based on the first reference standard and the absolute value of the sound velocity difference between each channel can be to compare the first reference standard with the absolute value of the sound velocity difference between each channel and then determine whether each channel has experienced wave skipping based on the number of comparison results. Alternatively, it can be to calculate the average value of the absolute value of the sound velocity difference between each channel and then compare it with the first reference standard and then determine whether each channel has experienced wave skipping based on the comparison results. This embodiment does not limit this method.

[0089] Step 105: In the flow rate determination case, calculate the flow rate measurement error of the current channel in each case, and determine the second reference standard based on the flow rate measurement error of the current channel in each case.

[0090] The flow velocity measurement error refers to the absolute value of the difference between the actual flow velocity value and the theoretical flow velocity value. It is used to evaluate the accuracy and precision of flow velocity measurement and reflects the gap between the measurement result and the true value. The second reference standard represents a reference standard determined in the flow velocity judgment situation for judging whether wave skipping occurs in the vocal tract.

[0091] Optionally, the method for determining the second reference standard based on the flow rate measurement error of the current channel under each condition may be to select the minimum value of the flow rate measurement error of the current channel under each condition as the second reference standard, or to select the average value, median, etc. of the flow rate measurement error of the current channel under each condition as the second reference standard. This embodiment does not limit this.

[0092] Step 106: Standardize the flow velocity of each channel to obtain the flow velocity of each channel at the axis of the flow meter.

[0093] In this flow meter, the flow velocity values ​​of different channels can be directly compared to determine the flow rate differences between channels. This embodiment standardizes the sound velocity of each channel by converting the flow velocity of each channel to the flow velocity at the axis of the flow meter, which allows for a better comparison of the flow velocity differences between different channels and enables the evaluation and analysis of the flow meter's performance.

[0094] Step 107: Calculate the absolute value of the velocity difference between each channel based on the flow velocity of each channel at the axis of the flow meter.

[0095] Step 108: Based on the second reference standard and the absolute value of the flow rate difference between each channel, determine whether wave skipping occurs in each channel.

[0096] Optionally, in this embodiment, the method of determining whether each channel has experienced wave skipping based on the second reference standard and the absolute value of the flow velocity difference between each channel can be to compare the second reference standard with the absolute value of the flow velocity difference between each channel and then determine whether each channel has experienced wave skipping based on the number of comparison results. Alternatively, it can be to calculate the average value of the absolute value of the flow velocity difference between each channel and then compare it with the second reference standard, and then determine whether each channel has experienced wave skipping based on the comparison results. This embodiment does not limit this method.

[0097] The technical concept of this invention is as follows: First, all cases of wave skipping in the current channel under forward / backward flow are listed, and these cases are divided into sound velocity judgment cases and flow velocity judgment cases. A first reference standard is determined based on the sound velocity measurement error of the current channel under the sound velocity judgment case, and a second reference standard is determined based on the flow velocity measurement error of the current channel under the flow velocity judgment case. Second, sound velocity judgment is performed first, that is, based on the first reference standard and the absolute value of the sound velocity difference between each channel, it is determined whether each channel has wave skipping, and anomaly screening of each channel is performed. Next, if no wave skipping channel is found through the above sound velocity judgment, flow velocity judgment is performed next, that is, based on the second reference standard and the absolute value of the flow velocity difference between each channel, it is determined whether each channel has wave skipping, so as to complete the final channel anomaly screening.

[0098] By categorizing all cases of abnormal channel skipping into sound velocity judgment and flow velocity judgment, and establishing corresponding reference standards for each category, these reference standards serve as the basis for verifying and calibrating channel measurement inaccuracies, providing a relatively reliable reference for channel anomaly screening. Simultaneously, both sound velocity and flow velocity are considered in determining whether channel skipping has occurred. By first performing sound velocity judgment based on the corresponding reference standards and the absolute value of the sound velocity difference between each channel, abnormal channels can be effectively screened. If no skipping channels are found, further flow velocity judgment based on the corresponding reference standards and the absolute value of the flow velocity difference between each channel is performed, achieving a more comprehensive and accurate screening of abnormal skipping channels. This provides a foundation for eliminating abnormal channel data caused by skipping, thereby ensuring the measurement accuracy and reliability of the four-channel ultrasonic gas flow meter.

[0099] In one embodiment of this specification, please refer to the appendix. Figure 2 The methods for classifying all cases of wave jumping in the current channel under both forward and reverse flow conditions into sound velocity judgment cases and flow velocity judgment cases include:

[0100] Step 201: Calculate the theoretical values ​​of sound velocity and flow velocity for the current channel under all conditions;

[0101] Step 202: Obtain the measured sound velocity and actual flow velocity of the current channel under all circumstances;

[0102] Step 203: Based on the difference between the theoretical and measured values ​​of sound velocity and flow velocity of the current channel, and the difference between the theoretical and actual values ​​of flow velocity, all cases of wave jumping in the current channel under forward / backward flow are divided into sound velocity judgment cases and flow velocity judgment cases.

[0103] In this embodiment, the method for calculating the theoretical values ​​of sound velocity and flow velocity of the current channel under all conditions is similar to the existing method for calculating the theoretical values ​​of sound velocity and flow velocity of the channel, and will not be described again here. Similarly, the method for obtaining the measured values ​​of sound velocity and flow velocity of the current channel under all conditions is similar to the existing method for obtaining the measured values ​​of sound velocity and flow velocity of the channel through calculation, and will not be described again here.

[0104] Optionally, this embodiment classifies all cases of wave jumping in the current channel under forward / backward flow conditions into sound velocity judgment cases and flow velocity judgment cases based on the difference between the theoretical and measured sound velocity values ​​of the current channel and the difference between the theoretical and actual flow velocity values. This can be achieved by classifying the cases based on the difference between the two values ​​exceeding a preset threshold, or by classifying the cases based on the rate of change calculated from the difference between the two values ​​exceeding a preset threshold. This embodiment does not limit this.

[0105] In one embodiment of this specification, a method for classifying all cases of wave jumping in the current channel under both forward and reverse flow conditions into sound velocity judgment cases and flow velocity judgment cases, based on the difference between the theoretical and measured sound velocity values ​​of the current channel and the difference between the theoretical and actual flow velocity values, includes:

[0106] If the difference between the theoretical and measured sound velocity values ​​of the current channel exceeds the first preset threshold, then the case of wave jumping in the current channel under forward / backward flow is classified into the sound velocity judgment case. If the difference between the theoretical and measured sound velocity values ​​of the current channel does not exceed the first preset threshold, then the case of wave jumping in the current channel under forward / backward flow is not processed.

[0107] If the difference between the theoretical and actual flow rates of the current channel exceeds the second preset threshold, then the case of wave skipping in the current channel under forward / backward flow will be classified as a flow rate judgment case. If the difference between the theoretical and actual flow rates of the current channel does not exceed the second preset threshold, then the case of wave skipping in the current channel under forward / backward flow will not be processed.

[0108] Wherein, the first preset threshold represents the maximum preset value of the sound velocity measurement error. The second preset threshold represents the maximum preset value of the flow velocity measurement error. Based on the above-listed cases of wave skipping in the current channel under both forward and reverse flow conditions, it can be understood that this embodiment does not need to consider cases where the absolute value of the difference between the theoretical and measured sound velocity exceeds the first preset threshold and the absolute value of the difference between the theoretical and actual flow velocity exceeds the second preset threshold.

[0109] In one embodiment of this specification, the method for determining a first reference standard based on the sound velocity measurement error of the current channel under various conditions includes:

[0110] The minimum sound velocity measurement error of the current channel under each sound velocity judgment condition is selected as the first reference standard.

[0111] Specifically, based on the above-listed cases of wave skipping in the current channel under forward / backward flow conditions, it can be understood that cases one, two, and five to eight are cases for judging sound speed. Therefore, the method for determining the first reference standard can be expressed as follows: Wherein, ΔC is the first reference standard. This refers to the absolute error between the measured and theoretical values ​​of the sound velocity in case one. This refers to the absolute error between the measured and theoretical values ​​of the sound velocity in the vocal tract in case two. This refers to the absolute error between the measured and theoretical values ​​of the sound velocity in case five. This refers to the absolute error between the measured and theoretical values ​​of the sound velocity in case six. This refers to the absolute error between the measured and theoretical values ​​of the sound velocity in case seven. It is the absolute error between the measured value of the channel sound velocity and the theoretical value of the sound velocity in case eight.

[0112] In one embodiment of this specification, the method for calculating the absolute value of the sound velocity difference between each channel includes:

[0113] Obtain the measured sound velocity value for each channel;

[0114] Calculate the absolute value of the difference between the measured sound velocity values ​​of each channel to obtain the absolute value of the sound velocity difference between each channel.

[0115] For example, the measured sound velocity values ​​of the four channels are obtained. ... , The absolute value of the difference between the measured sound velocity values ​​of each channel is and .

[0116] This embodiment calculates the absolute value of the difference between the measured sound velocity values ​​of each channel as the absolute value of the sound velocity difference between each channel. It can directly use the measured sound velocity values ​​of each channel that have been obtained for calculation, without the need for additional models, calibrations or correction factors, making the calculation process relatively simple and direct. It can promptly understand the sound velocity differences between each channel. At the same time, by calculating the difference using measured sound velocity values, the influence of actual fluid and actual environment on sound velocity measurement can be taken into account, which improves the reliability of the screening method provided in this embodiment to a certain extent.

[0117] In one embodiment of this specification, the method for determining whether wave skipping occurs in each channel based on a first reference standard and the absolute value of the sound velocity difference between each channel includes:

[0118] Select one channel and compare the absolute value of the sound velocity difference between the current channel and other channels with the first reference standard. If there are two or more absolute values ​​of the sound velocity difference between the current channel and other channels that are greater than the first reference standard, it is determined that the current channel has a wave skipping problem. If not, repeat the above steps for the next channel until all four channels have been compared.

[0119] For example, the measured sound velocity values ​​of the four channels are obtained. Then calculate the absolute value of the sound velocity difference between channel 1 and other channels. and If two or more sound velocity differences have an absolute value greater than ΔC, then channel 1 is considered to have a skipping waveform; if no two or more sound velocity differences have an absolute value greater than ΔC, then the absolute value of the sound velocity difference between channel 2 and other channels is calculated. , and If two or more sound velocity differences have an absolute value greater than ΔC, then channel 2 is considered to have a skipping waveform; if no two or more sound velocity differences have an absolute value greater than ΔC, then the absolute value of the sound velocity difference between channel 3 and other channels is calculated. and If two or more sound velocity differences have an absolute value greater than ΔC, then channel 3 is considered to have a skipping waveform; if no two or more sound velocity differences have an absolute value greater than ΔC, then the absolute value of the sound velocity difference between channel 4 and other channels is calculated. and If there are two or more sound velocity differences with an absolute value greater than ΔC, then it is determined that channel 4 has experienced a wave skipping; if there are no two or more sound velocity differences with an absolute value greater than ΔC, then all four channels have been compared and none of the four channels have experienced a wave skipping, then proceed to the next step 105.

[0120] This embodiment, by comparing the absolute value of the sound velocity difference between each channel and other channels with a first reference standard, can quickly determine whether a channel is experiencing wave skipping, enabling rapid screening of channels with abnormal wave skipping, improving processing efficiency, and reducing the impact of the absolute value of the sound velocity difference of a single channel on the judgment result, thus improving the accuracy and reliability of the screening method to a certain extent. Moreover, this embodiment, based on the comparison of the absolute value of the sound velocity difference, directly reflects the degree of difference between channels, and combined with the determined first reference standard, can intuitively determine whether the current channel is experiencing wave skipping.

[0121] In one embodiment of this specification, the method for determining a second reference standard based on the flow rate measurement error of the current channel under various conditions includes:

[0122] The minimum value among the flow rate measurement errors of the current channel under each flow rate judgment condition is selected as the second reference standard.

[0123] Specifically, based on all the cases of wave skipping in the current channel under forward / backward flow listed above, it can be understood that cases three and four are flow velocity judgment cases. Therefore, the method for determining the second reference standard can be expressed as follows: Where ΔV is the second reference standard, V is the actual value of the vocal tract velocity, and V is the theoretical value of the vocal tract velocity. This refers to the absolute error between the actual and theoretical values ​​of the duct flow velocity in case three. This is the absolute error between the actual value of the duct flow velocity and the theoretical value of the flow velocity in case four.

[0124] In one embodiment of this specification, the method for standardizing the flow velocity of each channel to obtain the flow velocity of each channel at the flowmeter axis includes:

[0125] Obtain the actual flow rate values ​​for the four audio channels;

[0126] The four channels are divided into channels near the tube wall and channels near the axis.

[0127] The quotient of the actual flow velocity of the channel near the pipe wall and the first preset coefficient is taken as the flow velocity of the channel near the pipe wall at the axis of the flowmeter. The quotient of the actual flow velocity of the channel near the axis and the second preset coefficient is taken as the flow velocity of the channel near the axis at the axis of the flowmeter.

[0128] Wherein, the first preset coefficient represents the preset proportional coefficient between the actual flow velocity of the channel near the pipe wall and the flow velocity of the channel near the pipe wall at the flowmeter axis, and the second preset coefficient represents the preset proportional coefficient between the actual flow velocity of the channel near the axis and the flow velocity of the channel near the axis at the flowmeter axis.

[0129] In a four-channel ultrasonic flow meter, the symmetrical channels near the pipe wall are typically used as receivers. These two channels are located on the outer side of the flow meter, close to the pipe wall. The symmetrical channels near the pipe wall primarily receive the acoustic signals after the gas flows through them. Due to their proximity to the pipe wall, these channels are influenced by it and can sense pressure and velocity changes generated by the interaction with the pipe wall during flow. By measuring these changes, the gas velocity and flow rate can be calculated more accurately. The symmetrical channel near the axis is typically used as the transmitter in a four-channel ultrasonic flow meter. It is located on the inner side of the flow meter, close to the pipe axis. The symmetrical channels near the axis primarily transmit acoustic signals, guiding the acoustic pulses into the gas for propagation. Because these channels are relatively far from the pipe wall, they experience less interference and can transmit and propagate acoustic signals more accurately.

[0130] For example, obtain the actual flow rate values ​​for the four audio channels. ,but This is the actual flow rate value for channel 1. This is the actual flow rate value for channel 2. This is the actual flow rate value for channel 3. This is the actual flow velocity value for channel 4. Obtain the flow velocity at the axis of the flow meter. Assuming channels 1 and 4 are symmetrical channels close to the tube wall, and channels 2 and 3 are symmetrical channels close to the axis, these are the first preset coefficients. This is the second preset coefficient. It converts the actual flow velocity values ​​of the four channels into the flow velocity of each channel at the flowmeter axis, i.e. ,in and It refers to the flow velocity of the sound channel near the pipe wall at the axis of the flow meter. and It is the flow velocity of the sound channel near the axis at the axis of the flow meter.

[0131] This embodiment standardizes the actual flow velocity of each channel to the flow velocity of each channel at the axis of the flowmeter, eliminating the influence of factors such as the position and layout of different channels on the flow velocity. This provides a more accurate basis for subsequently calculating the absolute value of the flow velocity difference between each channel and for determining whether each channel has skipped waves. To a certain extent, this improves the accuracy and precision of the channel anomaly screening method for a four-channel gas ultrasonic flowmeter proposed in this embodiment.

[0132] On the other hand, in this embodiment, the method for calculating the absolute value of the velocity difference between each channel based on the flow velocity of each channel at the axis of the flow meter includes:

[0133] Calculate the absolute value of the difference between the flow velocities of each channel at the axis of the flow meter to obtain the absolute value of the flow velocity difference between each channel.

[0134] For example, the flow velocity of the four channels at the axis of the flow meter is obtained as follows: The absolute value of the difference between the flow velocities of each channel at the axis of the flowmeter is... and .

[0135] In one embodiment of this specification, the method for determining whether channel skipping occurs based on a second reference standard and the absolute value of the flow velocity difference between channels includes:

[0136] Select one channel and compare the absolute value of the flow rate difference between the current channel and other channels with the second reference standard. If there are two or more absolute values ​​of the flow rate difference between the current channel and other channels that are greater than the second reference standard, it is determined that the current channel has a wave skipping problem. If not, repeat the above steps for the next channel until all four channels have been compared.

[0137] For example, the flow velocity of the four channels at the axis of the flow meter is obtained as follows: Then calculate the absolute value of the flow velocity difference between channel 1 and other channels. and If two or more velocity differences have an absolute value greater than ΔC, then channel 1 is considered to have a skipping event; if no two or more velocity differences have an absolute value greater than ΔC, then the absolute value of the velocity difference between channel 2 and other channels is calculated. , and If two or more flow rate differences have an absolute value greater than ΔC, then channel 2 is considered to have a skipping waveform; if no two or more flow rate differences have an absolute value greater than ΔC, then the absolute value of the flow rate difference between channel 3 and other channels is calculated. and If two or more flow rate differences have an absolute value greater than ΔC, then channel 3 is considered to have skipped waveforms; if no two or more flow rate differences have an absolute value greater than ΔC, then the absolute value of the flow rate difference between channel 4 and other channels is calculated. and If there are two or more flow rate differences with an absolute value greater than ΔC, then it is determined that channel 4 has skipped. If there are no two or more flow rate differences with an absolute value greater than ΔC, then all four channels have been compared and none of the four channels have skipped.

[0138] In this embodiment, after no abnormal skipping channels are found in the sound velocity judgment, flow velocity judgment is considered to continue. By comparing the absolute value of the flow velocity difference between each channel and other channels with a second reference standard, it is possible to quickly determine whether skipping occurs in each channel, achieving rapid screening of abnormal skipping channels, improving processing efficiency, and reducing the impact of the sound velocity judgment result of a single channel on the flow velocity judgment result. To a certain extent, this improves the accuracy and reliability of the channel anomaly screening method of the four-channel gas ultrasonic flow meter proposed in this embodiment. Moreover, this embodiment, based on the comparison of the absolute value of the flow velocity difference, directly reflects the degree of difference between channels. Combined with the determined second reference standard, it can intuitively determine whether the current channel has skipped, achieving a more comprehensive and accurate screening of abnormal skipping channels. This provides a basis for eliminating abnormal channel data caused by skipping, thereby ensuring the measurement accuracy and reliability of the four-channel gas ultrasonic flow meter.

[0139] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes, but is not limited to, the contents described in the accompanying drawings and the specific embodiments above. Any modifications that do not depart from the functional and structural principles of the present invention will be included within the scope of the claims.

Claims

1. A method for screening channel anomalies in a four-channel ultrasonic gas flow meter, characterized in that, Includes the following steps: List all cases of wave jumping in the current channel under forward / backward flow conditions, and divide all cases of wave jumping in the current channel under forward / backward flow conditions into sound velocity judgment cases and flow velocity judgment cases; In the case of sound velocity determination, the sound velocity measurement error of the current channel is calculated in each case, and the minimum value of the sound velocity measurement error of the current channel in each case is selected as the first reference standard. Calculate the absolute value of the sound velocity difference between each channel; Based on the first reference standard and the absolute value of the sound velocity difference between each channel, determine whether wave skipping occurs in each channel. If no wave skipping occurs in any of the four channels, proceed to the next step: In the flow rate determination case, the flow rate measurement error of the current channel is calculated in each case, and the minimum value of the flow rate measurement error of the current channel in each flow rate determination case is selected as the second reference standard; The flow velocity of each channel is standardized to obtain the flow velocity of each channel at the axis of the flow meter; Calculate the absolute value of the velocity difference between each channel based on the flow velocity of each channel at the axis of the flow meter. Based on the second reference standard and the absolute value of the flow rate difference between each channel, determine whether wave skipping occurs in each channel; The method for standardizing the flow velocity of each channel to obtain the flow velocity of each channel at the flowmeter axis includes: Obtain the actual flow rate values ​​for the four audio channels; The four channels are divided into channels near the tube wall and channels near the axis. The quotient of the actual flow velocity of the channel near the pipe wall and the first preset coefficient is taken as the flow velocity of the channel near the pipe wall at the axis of the flowmeter. The quotient of the actual flow velocity of the channel near the axis and the second preset coefficient is taken as the flow velocity of the channel near the axis at the axis of the flowmeter.

2. The method for screening channel anomalies in a four-channel ultrasonic gas flow meter as described in claim 1, characterized in that, The methods for categorizing all cases of wave jumping in the current sound channel under both forward and reverse flow conditions into sound velocity-based and flow velocity-based judgments include: Calculate the theoretical values ​​of sound velocity and flow velocity for the current channel under all conditions; Obtain the measured sound velocity and actual flow velocity of the current channel under all conditions; Based on the difference between the theoretical and measured sound velocity values ​​of the current channel and the difference between the theoretical and actual flow velocity values, all cases of wave jumping in the current channel under forward / backward flow are divided into sound velocity judgment cases and flow velocity judgment cases.

3. The method for screening channel anomalies in a four-channel ultrasonic gas flow meter as described in claim 2, characterized in that, Based on the difference between the theoretical and measured sound velocity values ​​of the current channel and the difference between the theoretical and actual flow velocity values, methods for classifying all cases of wave jumping in the current channel under both forward and reverse flow conditions into sound velocity-based and flow velocity-based cases include: If the difference between the theoretical and measured sound velocity values ​​of the current channel exceeds the first preset threshold, then the case of wave jumping in the current channel under forward / backward flow is classified into the sound velocity judgment case. If the difference between the theoretical and measured sound velocity values ​​of the current channel does not exceed the first preset threshold, then the case of wave jumping in the current channel under forward / backward flow is not processed. If the difference between the theoretical and actual flow rates of the current channel exceeds the second preset threshold, then the case of wave skipping in the current channel under forward / backward flow will be classified as a flow rate judgment case. If the difference between the theoretical and actual flow rates of the current channel does not exceed the second preset threshold, then the case of wave skipping in the current channel under forward / backward flow will not be processed.

4. The method for screening channel anomalies in a four-channel ultrasonic gas flow meter as described in claim 1, characterized in that, Methods for calculating the absolute value of the sound velocity difference between each channel include: Obtain the measured sound velocity value for each channel; Calculate the absolute value of the difference between the measured sound velocity values ​​of each channel to obtain the absolute value of the sound velocity difference between each channel.

5. The method for screening channel anomalies in a four-channel ultrasonic gas flow meter as described in claim 1, characterized in that, Methods for determining whether channel skipping occurs based on a first reference standard and the absolute value of the sound velocity difference between each channel include: Select one channel and compare the absolute value of the sound velocity difference between the current channel and other channels with the first reference standard. If there are two or more absolute values ​​of the sound velocity difference between the current channel and other channels that are greater than the first reference standard, it is determined that the current channel has a wave skipping problem. If not, repeat the above steps for the next channel until all four channels have been compared.

6. The method for screening channel anomalies in a four-channel ultrasonic gas flow meter as described in claim 1, characterized in that, Methods for calculating the absolute value of the velocity difference between channels based on the flow velocity of each channel at the axis of the flow meter include: Calculate the absolute value of the difference between the flow velocities of each channel at the axis of the flow meter to obtain the absolute value of the flow velocity difference between each channel.

7. The method for screening channel anomalies in a four-channel ultrasonic gas flow meter as described in claim 6, characterized in that, Methods for determining whether channel skipping occurs based on a second reference standard and the absolute value of the flow velocity difference between each channel include: Select one channel and compare the absolute value of the flow rate difference between the current channel and other channels with the second reference standard. If there are two or more absolute values ​​of the flow rate difference between the current channel and other channels that are greater than the second reference standard, it is determined that the current channel has a wave skipping problem. If not, repeat the above steps for the next channel until all four channels have been compared.

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