Method for improving the measurement response characteristics of 5×7 standard grid flowmeter under variable working conditions

Abstract

The present invention provides a method for improving the variable operating condition measurement response characteristics of a 5×7 standard grid flowmeter. The standard grid flowmeter includes five groups of pitot tubes, numbered 1-7, 8-14, 15-21, 22-28, and 29-35 in sequence along the longitudinal direction. The five groups of pitot tubes are arranged in sequence along the transverse direction. The pitot tubes in the five groups of pitot tubes are divided into four groups for round-robin measurement, and the measuring points of each group are arranged alternately and connected to their corresponding solenoid valves and then connected to differential pressure transmitters. The round-robin measurement measures the magnitude of the differential pressure signals of the seven connected pitot tubes. The flow velocity value corresponding to each pitot tube is respectively calculated, and the average flow velocity of the total 35 points is used as the average flow velocity of the measurement section and output in real time. The present invention adopts the technical idea of ​​round-robin measurement in five groups, with the measuring points of each group arranged alternately and the starting points of each group of round-robin measurement relatively dispersed. This method can quickly reflect the change in the flow velocity of the measurement section and improve the variable operating condition measurement response characteristics.

Description

Technical Field

[0001] The present invention relates to the technical field of gas flow monitoring, and in particular to a method for improving the variable working condition measurement response characteristics of a 5×7 standard grid flowmeter. Background Art

[0002] With the rapid development of the national economy, the thermal power generation industry is increasingly demanding precise measurement of large gas flows. To meet the ever-increasing demands for gas flow measurement accuracy and traceability, standard grid flowmeter technology has been developed. Designed based on the differential pressure principle, standard grid flowmeters offer high reliability and maintain high accuracy even in non-uniform flow fields. This creates a relatively complete traceability system, eliminating the need for on-site manual calibration of flow coefficients.

[0003] When measuring flow rates in large-diameter rectangular cross-sections, a standard grid flowmeter generally requires no more than 36 measuring points. For applications with short rectangular flue duct sections and uneven velocity distribution across the measurement cross-section, the upper limit of 36 measuring points is recommended. When the long and short sides of the rectangular cross-section are close together, a 5×7 grid layout is recommended. A standard grid flowmeter measures the velocity at each grid point in a rotating cycle, with each measurement lasting approximately 5 seconds. It then outputs a sliding average velocity across all 35 grid points. If each measurement lasts 5 seconds, the cycle for rotating all 35 grid points is 175 seconds. If operating conditions change within this cycle, the average velocity output by the standard grid flowmeter deviates significantly from the true value, resulting in significant measurement lag. Conventional standard grid flowmeters measure the velocity at each grid point in a rotating cycle. However, when operating conditions change, the concentration of several measuring points within a small area of ​​the measurement cross-section within a short period of time makes it difficult to quickly reflect changes in the velocity across the measurement cross-section. Consequently, the measurement response to changing operating conditions is poor. Summary of the Invention

[0004] The object of the present invention is to provide a method for improving the variable operating condition measurement response characteristics of a 5×7 standard grid method flowmeter, so as to improve the accuracy and real-time response of the standard grid method flowmeter in measuring variable operating condition flow.

[0005] According to one object of the present invention, the present invention provides a method for improving the variable operating condition measurement response characteristics of a 5×7 standard grid flowmeter, comprising the following steps:

[0006] S1, flow meter arrangement

[0007] The standard grid flowmeter includes five groups of pitot tubes numbered 1-7, 8-14, 15-21, 22-28, and 29-35 in the longitudinal direction, and the five groups of pitot tubes are arranged in sequence in the transverse direction;

[0008] The seven Pitot tubes numbered 1, 3, 5, 7, 30, 32, and 34 are connected to their corresponding solenoid valves and then connected to the first differential pressure transmitter;

[0009] The seven Pitot tubes numbered 2, 4, 6, 29, 31, 33, and 35 are connected to their corresponding solenoid valves and then connected to the second differential pressure transmitter;

[0010] The seven Pitot tubes numbered 8, 10, 12, 14, 23, 25, and 27 are connected to their corresponding solenoid valves and then connected to the third differential pressure transmitter;

[0011] A total of seven Pitot tubes numbered 9, 11, 13, 22, 24, 26, and 28 are connected to their corresponding solenoid valves and then connected to a fourth differential pressure transmitter;

[0012] The seven Pitot tubes numbered 15-21 are connected to their corresponding solenoid valves and then connected to the fifth differential pressure transmitter;

[0013] S2, patrol measurement of pitot tube differential pressure signal

[0014] The first differential pressure transmitter, the second differential pressure transmitter, the third differential pressure transmitter, the fourth differential pressure transmitter and the fifth differential pressure transmitter all measure the differential pressure signals of the seven Pitot tubes connected to them in a patrol manner.

[0015] S3, calculate the average flow rate value

[0016] The flow velocity value corresponding to each of the Pitot tubes is obtained respectively, and the average flow velocity value of 35 points is used as the average flow velocity value of the measurement section and output in real time.

[0017] Furthermore, in S1, each group of the Pitot tubes is connected to the corresponding first differential pressure transmitter, the second differential pressure transmitter, the third differential pressure transmitter, the fourth differential pressure transmitter or the fifth differential pressure transmitter in turn through the on-off of the corresponding solenoid valve.

[0018] Furthermore, in S2, the duration for which each of the Pitot tube differential pressure signals is connected to the corresponding first differential pressure transmitter, the second differential pressure transmitter, the third differential pressure transmitter, the fourth differential pressure transmitter or the fifth differential pressure transmitter is consistent.

[0019] Furthermore, the duration for each of the Pitot tube differential pressure signals to connect to the corresponding first differential pressure transmitter, the second differential pressure transmitter, the third differential pressure transmitter, the fourth differential pressure transmitter or the fifth differential pressure transmitter is 3-10 seconds.

[0020] Further, in S1, the seven Pitot tubes numbered 1, 30, 3, 32, 5, 34, and 7 are connected to the first differential pressure transmitter in sequence through the on-off of their corresponding solenoid valves; the seven Pitot tubes numbered 35, 6, 33, 4, 31, 2, and 29 are connected to the second differential pressure transmitter in sequence through the on-off of their corresponding solenoid valves; the seven Pitot tubes numbered 8, 23, 10, 25, 12, 27, and 14 are connected to the third differential pressure transmitter in sequence through the on-off of their corresponding solenoid valves; the seven Pitot tubes numbered 28, 13, 26, 11, 24, 9, and 22 are connected to the fourth differential pressure transmitter in sequence through the on-off of their corresponding solenoid valves; and the seven Pitot tubes numbered 15-21 are connected to the fifth differential pressure transmitter in sequence through the on-off of their corresponding solenoid valves.

[0021] Furthermore, the five Pitot tube differential pressure signals numbered 1, 35, 8, 28, and 15 are respectively connected to the first differential pressure transmitter, the second differential pressure transmitter, the third differential pressure transmitter, the fourth differential pressure transmitter, or the fifth differential pressure transmitter at the same time.

[0022] Further, in S1, the seven Pitot tubes numbered 1, 30, 3, 32, 5, 34, and 7 are connected to the first differential pressure transmitter in sequence through the on-off of their corresponding solenoid valves; the seven Pitot tubes numbered 29, 2, 31, 4, 33, 6, and 35 are connected to the second differential pressure transmitter in sequence through the on-off of their corresponding solenoid valves; the seven Pitot tubes numbered 14, 27, 12, 25, 10, 23, and 8 are connected to the third differential pressure transmitter in sequence through the on-off of their corresponding solenoid valves; the seven Pitot tubes numbered 28, 13, 26, 11, 24, 9, and 22 are connected to the fourth differential pressure transmitter in sequence through the on-off of their corresponding solenoid valves; and the seven Pitot tubes numbered 15-21 are connected to the fifth differential pressure transmitter in sequence through the on-off of their corresponding solenoid valves.

[0023] Furthermore, the five Pitot tube differential pressure signals numbered 1, 29, 14, 28, and 15 are respectively connected to the first differential pressure transmitter, the second differential pressure transmitter, the third differential pressure transmitter, the fourth differential pressure transmitter, or the fifth differential pressure transmitter at the same time.

[0024] Further, the first differential pressure transmitter, the second differential pressure transmitter, the third differential pressure transmitter, the fourth differential pressure transmitter and the fifth differential pressure transmitter are the same differential pressure transmitters.

[0025] Furthermore, the duration for each Pitot tube differential pressure signal to connect to the corresponding first differential pressure transmitter, the second differential pressure transmitter, the third differential pressure transmitter, the fourth differential pressure transmitter or the fifth differential pressure transmitter is 5 seconds.

[0026] The technical solution of the present invention adopts the technical idea of ​​dividing the measurement into five groups, arranging the measuring points of each group alternately, and the starting points of each group of round-robin measurement are relatively dispersed. It can quickly reflect the change in the flow velocity of the measuring section and improve the measurement response characteristics of variable working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 Schematic diagram of the distribution of the variable working condition measurement response characteristics of the 5×7 standard grid method flow meter in an embodiment of the present invention. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore should not be understood as limiting the present invention.

[0031] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a communication between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0032] Example 1

[0033] like Figure 1 As shown,

[0034] A method for improving the variable-condition measurement response characteristics of a 5×7 standard grid flowmeter comprises the following steps:

[0035] S1, flow meter arrangement

[0036] The standard grid flowmeter includes five groups of pitot tubes numbered 1-7, 8-14, 15-21, 22-28, and 29-35 in the longitudinal direction. The five groups of pitot tubes are arranged in sequence in the transverse direction, wherein:

[0037] Seven Pitot tubes numbered 1, 3, 5, 7, 30, 32, and 34 are connected to their corresponding solenoid valves and then to the first differential pressure transmitter;

[0038] The seven Pitot tubes numbered 2, 4, 6, 29, 31, 33, and 35 are connected to their corresponding solenoid valves and then to the second differential pressure transmitter;

[0039] The seven Pitot tubes numbered 8, 10, 12, 14, 23, 25, and 27 are connected to their corresponding solenoid valves and then connected to the third differential pressure transmitter;

[0040] Seven Pitot tubes numbered 9, 11, 13, 22, 24, 26, and 28 are connected to their corresponding solenoid valves and then to the fourth differential pressure transmitter;

[0041] Seven Pitot tubes numbered 15-21 are connected to their corresponding solenoid valves and then to the fifth differential pressure transmitter;

[0042] S2, patrol measurement of pitot tube differential pressure signal

[0043] The first differential pressure transmitter, the second differential pressure transmitter, the third differential pressure transmitter, the fourth differential pressure transmitter and the fifth differential pressure transmitter all cycle and repeatedly measure the differential pressure signals of the seven Pitot tubes connected to them;

[0044] S3, calculate the average flow rate value

[0045] The flow velocity value corresponding to each Pitot tube is calculated respectively. The time length for each Pitot tube differential pressure signal to be connected to the differential pressure transmitter is consistent, which is between 3-10s. The average flow velocity value of 35 points is used as the average flow velocity value of the measurement section and output in real time.

[0046] Example 2

[0047] The steps of this embodiment are basically the same as those of the embodiment, except that, in order to improve the variable operating condition measurement response characteristics of the above-mentioned standard grid method flowmeter, the seven pitot tubes numbered 1, 30, 3, 32, 5, 34, and 7 are connected to the first differential pressure transmitter in turn through the on-off of their corresponding solenoid valves; the seven pitot tubes numbered 35, 6, 33, 4, 31, 2, and 29 are connected to the second differential pressure transmitter in turn through the on-off of their corresponding solenoid valves; the seven pitot tubes numbered 8, 23, 10, 25, 12, 27, and 14 are connected to the third differential pressure transmitter in turn through the on-off of their corresponding solenoid valves; the seven pitot tubes numbered 28, 13, 26, 11, 24, 9, and 22 are connected to the fourth differential pressure transmitter in turn through the on-off of their corresponding solenoid valves; and the seven pitot tubes numbered 15-21 are connected to the fifth differential pressure transmitter in turn through the on-off of their corresponding solenoid valves. The differential pressure signals of the five Pitot tubes numbered 1, 35, 8, 28 and 15 are respectively connected to the first differential pressure transmitter, the second differential pressure transmitter, the third differential pressure transmitter, the fourth differential pressure transmitter and the fifth differential pressure transmitter.

[0048] Example 3

[0049] The steps of this embodiment are basically the same as those of the embodiment. The difference is that, in order to improve the variable working condition measurement response characteristics of the above-mentioned standard grid method flowmeter, the seven pitot tubes numbered 1, 30, 3, 32, 5, 34, and 7 are connected to the first differential pressure transmitter in turn through the on-off of their corresponding solenoid valves, the seven pitot tubes numbered 29, 2, 31, 4, 33, 6, and 35 are connected to the second differential pressure transmitter in turn through the on-off of their corresponding solenoid valves, and the seven pitot tubes numbered 14, 27, 12, 25, 10, 23, and 8 are connected to the second differential pressure transmitter in turn through the on-off of their corresponding solenoid valves. The solenoid valves are turned on and off in turn to connect to the third differential pressure transmitter. The seven pitot tubes numbered 28, 13, 26, 11, 24, 9, and 22 are turned on and off in turn to connect to the fourth differential pressure transmitter through their corresponding solenoid valves; the seven pitot tubes numbered 15-21 are turned on and off in turn to connect to the fifth differential pressure transmitter through their corresponding solenoid valves; the differential pressure signals of the five pitot tubes numbered 1, 29, 14, 28, and 15 are simultaneously connected to the first differential pressure transmitter, the second differential pressure transmitter, the third differential pressure transmitter, the fourth differential pressure transmitter, and the fifth differential pressure transmitter.

[0050] In the above embodiment, in order to improve the measurement response speed of the standard grid method flowmeter and ensure sufficient measurement response at each point, the time length for the differential pressure signal of each Pitot tube to be connected to the differential pressure transmitter is 5 seconds.

[0051] In the above embodiment, in order to improve the measurement accuracy of the standard grid method flowmeter, the specifications and models of the above four sets of differential pressure transmitters are consistent.

[0052] The present invention provides a method for improving the variable operating condition measurement response characteristics of a 5×7 standard grid method flowmeter, which can be used for point source carbon emission monitoring, and specifically for large-caliber gas flow monitoring in the thermal power generation industry.

[0053] The present invention adopts the technical idea of ​​dividing the measurement into five groups, arranging the measuring points of each group alternately, and the starting points of each group of round-robin measurement are relatively dispersed. It can quickly reflect the change of the flow velocity of the measuring section and improve the measurement response characteristics of variable working conditions.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for improving the variable operating condition measurement response characteristics of a 5×7 standard grid flowmeter, characterized in that: The steps include: S1, flow meter arrangement The standard grid flowmeter includes five groups of pitot tubes numbered 1-7, 8-14, 15-21, 22-28, and 29-35 in the longitudinal direction, and the five groups of pitot tubes are arranged in sequence in the transverse direction; The seven Pitot tubes numbered 1, 3, 5, 7, 30, 32, and 34 are connected to their corresponding solenoid valves and then connected to the first differential pressure transmitter; The seven Pitot tubes numbered 2, 4, 6, 29, 31, 33, and 35 are connected to their corresponding solenoid valves and then connected to the second differential pressure transmitter; The seven Pitot tubes numbered 8, 10, 12, 14, 23, 25, and 27 are connected to their corresponding solenoid valves and then connected to the third differential pressure transmitter; A total of seven Pitot tubes numbered 9, 11, 13, 22, 24, 26, and 28 are connected to their corresponding solenoid valves and then connected to a fourth differential pressure transmitter; The seven Pitot tubes numbered 15-21 are connected to their corresponding solenoid valves and then connected to the fifth differential pressure transmitter; S2, patrol measurement of pitot tube differential pressure signal The first differential pressure transmitter, the second differential pressure transmitter, the third differential pressure transmitter, the fourth differential pressure transmitter and the fifth differential pressure transmitter all measure the differential pressure signals of the seven Pitot tubes connected to them in a patrol manner; S3, calculate the average flow rate value The flow velocity value corresponding to each of the Pitot tubes is obtained respectively, and the average flow velocity value of 35 points is used as the average flow velocity value of the measurement section and output in real time.

2. The method for improving the variable working condition measurement response characteristics of a 5×7 standard grid flowmeter according to claim 1, characterized in that: In S1, each group of the Pitot tubes is connected to the corresponding first differential pressure transmitter, the second differential pressure transmitter, the third differential pressure transmitter, the fourth differential pressure transmitter or the fifth differential pressure transmitter in turn through the on-off switching of the corresponding solenoid valve.

3. The method for improving the variable working condition measurement response characteristics of a 5×7 standard grid flowmeter according to claim 2, characterized in that: In S2, the duration for which each of the Pitot tube differential pressure signals is connected to the corresponding first differential pressure transmitter, the second differential pressure transmitter, the third differential pressure transmitter, the fourth differential pressure transmitter, or the fifth differential pressure transmitter is consistent.

4. The method for improving the variable operating condition measurement response characteristics of a 5×7 standard grid flowmeter according to claim 3, characterized in that: The time duration for each of the Pitot tube differential pressure signals to be connected to the corresponding first differential pressure transmitter, the second differential pressure transmitter, the third differential pressure transmitter, the fourth differential pressure transmitter or the fifth differential pressure transmitter is 3-10 seconds.

5. The method for improving the variable working condition measurement response characteristics of a 5×7 standard grid flowmeter according to claim 1, characterized in that: In S1, the seven Pitot tubes numbered 1, 30, 3, 32, 5, 34, and 7 are connected to the first differential pressure transmitter in sequence through the on-off of their corresponding solenoid valves; the seven Pitot tubes numbered 35, 6, 33, 4, 31, 2, and 29 are connected to the second differential pressure transmitter in sequence through the on-off of their corresponding solenoid valves; the seven Pitot tubes numbered 8, 23, 10, 25, 12, 27, and 14 are connected to the third differential pressure transmitter in sequence through the on-off of their corresponding solenoid valves; the seven Pitot tubes numbered 28, 13, 26, 11, 24, 9, and 22 are connected to the fourth differential pressure transmitter in sequence through the on-off of their corresponding solenoid valves; and the seven Pitot tubes numbered 15-21 are connected to the fifth differential pressure transmitter in sequence through the on-off of their corresponding solenoid valves.

6. The method for improving the variable operating condition measurement response characteristics of a 5×7 standard grid flowmeter according to claim 5, characterized in that: The five Pitot tube differential pressure signals numbered 1, 35, 8, 28, and 15 are respectively connected to the first differential pressure transmitter, the second differential pressure transmitter, the third differential pressure transmitter, the fourth differential pressure transmitter, or the fifth differential pressure transmitter at the same time.

7. The method for improving the variable operating condition measurement response characteristics of a 5×7 standard grid flowmeter according to claim 1, characterized in that: In S1, the seven Pitot tubes numbered 1, 30, 3, 32, 5, 34, and 7 are connected to the first differential pressure transmitter in sequence through the on-off of their corresponding solenoid valves; the seven Pitot tubes numbered 29, 2, 31, 4, 33, 6, and 35 are connected to the second differential pressure transmitter in sequence through the on-off of their corresponding solenoid valves; the seven Pitot tubes numbered 14, 27, 12, 25, 10, 23, and 8 are connected to the third differential pressure transmitter in sequence through the on-off of their corresponding solenoid valves; the seven Pitot tubes numbered 28, 13, 26, 11, 24, 9, and 22 are connected to the fourth differential pressure transmitter in sequence through the on-off of their corresponding solenoid valves; the seven Pitot tubes numbered 15-21 are connected to the fifth differential pressure transmitter in sequence through the on-off of their corresponding solenoid valves.

8. The method for improving the variable operating condition measurement response characteristics of a 5×7 standard grid flowmeter according to claim 7, characterized in that: The five Pitot tube differential pressure signals numbered 1, 29, 14, 28, and 15 are respectively connected to the first differential pressure transmitter, the second differential pressure transmitter, the third differential pressure transmitter, the fourth differential pressure transmitter, or the fifth differential pressure transmitter at the same time.

9. The method for improving the variable operating condition measurement response characteristics of a 5×7 standard grid flowmeter according to claim 1, characterized in that: The first differential pressure transmitter, the second differential pressure transmitter, the third differential pressure transmitter, the fourth differential pressure transmitter, and the fifth differential pressure transmitter are identical differential pressure transmitters.

10. The method for improving the variable working condition measurement response characteristics of a 5×7 standard grid flowmeter according to claim 1, characterized in that: The duration for each Pitot tube differential pressure signal to be connected to the corresponding first differential pressure transmitter, the second differential pressure transmitter, the third differential pressure transmitter, the fourth differential pressure transmitter or the fifth differential pressure transmitter is 5 seconds.

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