Air volume measuring device and method

Abstract

The device comprises a main pipeline and a probe assembly, the insertion depth of the probe assembly in an air duct can be adjusted, probe layout is customized according to an actual measurement space model, a probe is arranged in an optimal area of a flow field, a low-speed area and a turbulent flow area with strong circulating airflow are effectively avoided, and the air flow measurement accuracy is improved. The accumulation and blocking effects of particulate matters on the probe are greatly weakened, the problem of measurement misalignment caused by poor position of the probe is fundamentally solved, the accuracy, linearity and representativeness of measurement are remarkably improved, and the maintenance workload of equipment is greatly reduced. Meanwhile, the device has adjustability, not only can perfectly adapt to the working condition of a specific pipeline during primary installation, but also can conveniently adjust the depth of the probe on line when the working condition changes in the future, has extremely high adaptability and flexibility, effectively supports the accurate operation of an automatic control system, reduces the shutdown risk, and improves the working efficiency. And the overall efficiency of the industrial process is improved.

Description

Technical Field

[0001] The invention relates to the field of wind volume measurement, in particular to a wind volume measuring device. Background Art

[0002] In many industrial fields such as electricity, chemical industry, metallurgy and environmental protection, accurate measurement of the flow of gas, flue gas or dust-laden gas in pipelines is a key link in ensuring process stability, improving energy efficiency and controlling pollutant emissions. At present, insertable multi-point matrix flow measurement devices are widely used because they can obtain the average flow velocity of the pipeline cross section. However, the fluid dynamic field inside industrial pipelines is often very complex, full of uneven velocity distribution, eddies and turbulent areas. Traditional matrix flow devices usually use a standardized, fixed insertion depth probe layout. This layout is difficult to fully match the complex and non-ideal flow field in a specific pipeline during installation. When the probe is incorrectly placed in an area where the flow velocity is too low or there is backflow, the representativeness and accuracy of its measurement will be greatly reduced, directly affecting the accuracy and reliability of the entire automation control system.

[0003] When the fluid medium contains dust, droplets, or other particulate matter, the above problems become more serious. In an undesirable flow field, local circulating airflow is easily formed around the probe, causing particles in the medium to quickly accumulate on the probe surface and internal sampling channel, resulting in blockage or contamination, which is called probe fouling. This fouling phenomenon will continuously change the aerodynamic characteristics of the probe, causing the measurement signal to drift, fluctuate violently, or even become completely inaccurate in a short period of time. Conventional online maintenance methods such as external backflushing often only treat the symptoms and not the root cause, and it is difficult to effectively remove dust or attachments inside the probe. This not only leads to a huge maintenance workload for the device, but also when multiple devices are used for process ratio control, such as air distribution control in the combustion process, the measurement deviations caused by different degrees of fouling between the devices will directly disrupt the material balance of the process, leading to a series of problems such as energy waste, reduced product quality, and even safety risks. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is that the existing air volume measuring device is easily blocked by dirt and loses accuracy due to the poor layout of the probe.

[0005] The above technical problems are solved by the following technical solutions:

[0006] The present invention provides an air volume measurement device, which includes a main pipe and one or more probe assemblies.

[0007] In a preferred embodiment of the air volume measuring device of the present invention: a main pipe is horizontally arranged at the top of the air duct, and the axis of the main pipe is perpendicular to the axis of the air duct; and

[0008] One or more probe assemblies, the top of which is connected to the main pipe and the bottom of which passes through the top of the air duct;

[0009] The probe assembly can adjust the insertion depth of the probe assembly in the air duct according to a spatial model representing the fluid dynamic field inside the air duct.

[0010] In a preferred embodiment of the air volume measuring device of the present invention: the probe assembly includes a probe branch pipe and a probe, the probe branch pipe is arranged at the bottom of the main pipe, the total length of the probe branch pipe can be changed, and the probe is arranged at the bottom of the probe branch pipe.

[0011] In a preferred embodiment of the air volume measuring device of the present invention, the probe branch pipe is a segmented threaded connection structure, comprising at least two pipe body sections and a connecting sleeve.

[0012] In a preferred embodiment of the air volume measuring device of the present invention, the connecting end of each of the tube sections is provided with an external thread, and the inner wall of the connecting sleeve is provided with an internal thread matching the external thread of the tube section.

[0013] In a preferred embodiment of the air volume measuring device of the present invention, the axial direction of the probe branch pipe is perpendicular to the axial direction of the air duct and the axial direction of the main line.

[0014] In a preferred embodiment of the wind volume measuring device of the present invention, the spatial model is established based on data obtained by actually measuring wind speeds at multiple locations and depths within the wind duct.

[0015] In a preferred embodiment of the air volume measuring device of the present invention, the insertion depth is within a linear region where the ends of all the probe assemblies are arranged in the air duct.

[0016] In a preferred embodiment of the wind volume measuring device of the present invention: the linear region is a region where the wind speed difference is less than a preset threshold.

[0017] The present invention also proposes a method for measuring air volume, which includes establishing a space model, adjusting the insertion depth, monitoring the air duct and calculating the air volume.

[0018] In a preferred embodiment of the air volume measurement method of the present invention: a spatial model is established to characterize the fluid dynamic field inside the air duct;

[0019] adjusting the insertion depth of the probe assembly into the air duct according to the spatial model; and

[0020] The adjusted probe assembly is used to monitor the air duct and calculate the air volume.

[0021] In a preferred embodiment of the air volume measurement method of the present invention, the step of establishing a spatial model specifically includes:

[0022] The air duct is evenly divided into a plurality of spaces along a cross section perpendicular to the wind direction, and wind speed data of each space is measured;

[0023] Analyzing and determining, based on the measured wind speed data, the area in the air duct where the flow field is linear; and

[0024] The linear region is determined as a target adjustment region of the insertion depth of the probe assembly.

[0025] The beneficial effects of the present invention are as follows: by customizing the probe layout based on the measured spatial model and placing the probe in the optimal area of ​​the flow field, the low-speed and turbulent areas with strong circulating airflow are effectively avoided, and the accumulation and clogging effects of particulate matter on the probe are greatly reduced. This fundamentally solves the problem of measurement inaccuracy caused by poor probe positioning, significantly improves the accuracy, linearity and representativeness of the measurement, and greatly reduces the maintenance workload of the equipment. At the same time, the device of the present invention is adjustable. Not only can it perfectly adapt to the working conditions of a specific pipeline during initial installation, but when the working conditions change in the future, the probe depth can also be conveniently adjusted online. It has strong adaptability and flexibility, effectively supports the precise operation of the automation control system, reduces the risk of downtime, and improves the overall efficiency of the industrial process. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings of the embodiments of the present invention. Obviously, the drawings described below only relate to some embodiments of the present invention, and are not intended to limit the present invention.

[0027] Figure 1 shows the overall schematic diagram of the air volume measurement device;

[0028] Figure 2 A schematic diagram of the probe branch is shown;

[0029] Figure 3 A flow chart of the air volume measurement method is shown. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below with reference to specific embodiments and the accompanying drawings.

[0031] The terms used in the present invention are those commonly used in the art in view of the functions of the present invention, but these terms may vary according to the intentions of those skilled in the art, precedents, or new technologies in the art. In addition, specific terms may be selected by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the present invention. Therefore, the terms used in the specification should not be understood as simple names, but rather as the meanings of the terms and the overall description of the present invention.

[0032] Reference Figure 1 and Figure 2 This embodiment provides an air volume measuring device, including a main pipe 1 and one or more probe assemblies 2.

[0033] Specifically, a main pipe 1 is horizontally arranged at the top of the air duct F, and the axis of the main pipe 1 is perpendicular to the axis of the air duct F; one or more probe assemblies 2 are connected to the main pipe 1 at the top and pass through the top of the air duct F at the bottom; wherein the probe assembly 2 can adjust the insertion depth of the probe assembly 2 in the air duct F according to the spatial model representing the fluid dynamic field inside the air duct F.

[0034] The main pipe 1 is a hollow metal pipe, which serves as the mounting base and signal collection channel for multiple probe assemblies 2, and aggregates the signals collected by all probes, such as pressure. It is horizontally arranged on the top outer wall of the air duct F.

[0035] The main flow direction of the secondary air in the air duct F is the axial direction of the air duct, and the axis of the main line 1 is perpendicular to the axial direction of the air duct. The main line 1 is also equipped with a buffer tank and an ash prevention slope, and ash discharge plugs are installed at the beginning and end of the main line 1.

[0036] The probe assembly 2 measures wind speed at various locations within the air duct. In this embodiment, five probe assemblies 2 are installed, dividing the air duct into five equal sections horizontally and 12 equal sections vertically, along a vertical section passing through the axis of the main line 1. The top of each probe assembly 2 connects to the inner cavity of the main line 1 via a connecting pipe, while its bottom extends into the interior of the duct F through a pre-set mounting hole at the top.

[0037] The insertion depth of each probe assembly 2 in the air duct F is adjustable, so as to measure the wind speed at each location in the air duct F.

[0038] Before installing the device, a spatial model representing the fluid dynamic field within the specific duct F needs to be established. This model is constructed by creating several calibration holes at various locations on the top wall of duct F. In this embodiment, there are five calibration holes. Under different load conditions, a standard velocity measuring instrument, such as a Pitot tube, is inserted into the duct through each calibration hole. The actual wind speed and flow direction data for all measurement points at different cross-sections and depths within the duct are measured and recorded. By recording these three-dimensional coordinates and the corresponding flow velocity data, a digital spatial model is constructed that reflects the flow velocity distribution patterns within the entire duct. This spatial model is analyzed to identify the "optimal measurement region" where the flow field is most stable, the flow velocity distribution is most uniform, and the average flow velocity for that cross-section is most representative. This region is defined as the area where the wind velocity difference is less than a preset threshold. In a preferred embodiment of the present invention, the preset threshold can be 8 m / s, more preferably 5 m / s. This region corresponds to one or more specific depth ranges. It can also be analyzed that the wind velocity distribution at each point in the cross-section is uneven. Measurements show that the wind velocity in the upper and middle layers is relatively good, while the wind velocity at the bottom layer is almost zero.

[0039] When installing the probe assemblies 2, the insertion depth of each probe assembly 2 in the air duct F is adjusted so that the measuring portion of its distal end is precisely within the "optimal measurement area" determined in the previous step. In this way, the device of the present invention can adjust the insertion depth based on the spatial model, thereby achieving the most accurate measurement.

[0040] Reference Figure 1 and Figure 2 Based on the previous embodiment, this embodiment provides an air volume measuring device, including a main pipe 1 and one or more probe assemblies 2.

[0041] Specifically, a main pipe 1 is horizontally arranged at the top of the air duct F, and the axis of the main pipe 1 is perpendicular to the axis of the air duct F; one or more probe assemblies 2 are connected to the main pipe 1 at the top and pass through the top of the air duct F at the bottom; wherein the probe assembly 2 can adjust the insertion depth of the probe assembly 2 in the air duct F according to the spatial model representing the fluid dynamic field inside the air duct F.

[0042] The main pipe 1 is a hollow metal pipe, which serves as the mounting base and signal collection channel for multiple probe assemblies 2, and aggregates the signals collected by all probes, such as pressure. It is horizontally arranged on the top outer wall of the air duct F.

[0043] The main flow direction of the secondary air in the air duct F is the axial direction of the air duct, and the axis of the main line 1 is perpendicular to the axial direction of the air duct. The main line 1 is also equipped with a buffer tank and an ash prevention slope, and ash discharge plugs are installed at the beginning and end of the main line 1.

[0044] The probe assembly 2 measures wind speed at various locations within the air duct. In this embodiment, five probe assemblies 2 are installed, dividing the air duct into five equal sections horizontally and 12 equal sections vertically, along a vertical section passing through the axis of the main line 1. The top of each probe assembly 2 connects to the inner cavity of the main line 1 via a connecting pipe, while its bottom extends into the interior of the duct F through a pre-set mounting hole at the top.

[0045] The insertion depth of each probe assembly 2 in the air duct F is adjustable, so as to measure the wind speed at each location in the air duct F.

[0046] Specifically, the probe assembly 2 includes a probe branch 21 and a probe 22. The probe branch 21 is installed at the bottom of the main pipe 1 and can be adjusted in length. The probe 22 is installed at the bottom of the probe branch 21. The probe branch 21 has a segmented threaded connection structure and includes at least two pipe sections 211 and a connecting sleeve 212. The connecting end of each pipe section 211 is provided with external threads, and the inner wall of the connecting sleeve 212 is provided with internal threads that mate with the external threads of the pipe sections 211.

[0047] By adjusting the number of tube body sections 211 and connecting sleeves 212, the length of the probe branch pipe 21 can be adjusted over a large range. By adjusting the spiral depth of the tube body section 211 and the connecting sleeve 212, the length of the probe branch pipe 21 can be adjusted over a small range. In this way, the length of the probe branch pipe 21 can be adjusted freely within a certain range, and the probe 22 can be inserted into any depth of the air duct F, thereby facilitating the measurement of wind speed.

[0048] The probe branch pipe 21 is axially perpendicular to the axial direction of the air duct F and the axial direction of the main line 1. Ensure that the probe 22 is facing the incoming flow direction to obtain the most accurate dynamic pressure signal

[0049] Specifically, the spatial model is established based on data obtained from actual wind speed measurements at multiple locations and depths within the air duct F. When installing the probe assembly 2, by adjusting the probe assembly 2 to different depths within the air duct F, actual wind speed data for each spatial point is obtained, which is used to determine the final suitable location for installing the probe 22.

[0050] Specifically, the insertion depth is within the linear region where the distal ends of all probe assemblies 2 are positioned within the air duct F. This linear region is the ideal location for installing the probe 22, where the flow field is most stable, the velocity distribution is most uniform, and it best represents the average velocity of the cross-section. This region is where the wind velocity difference is less than a preset threshold. In a preferred embodiment of the present invention, the preset threshold may be 8 m / s, more preferably 5 m / s.

[0051] Reference Figure 3,This embodiment provides a method for measuring air volume, including establishing a space model, adjusting the insertion depth, monitoring the air duct and calculating the air volume.

[0052] Calibration holes are made above the duct—five in this example—to evenly divide the duct horizontally into five sections. The probe assembly's length is adjusted to allow for even lowering, dividing the duct vertically into 12 sections. This evenly divides the duct cross-section, making it easier for the probe to measure wind speed at every location. All collected three-dimensional coordinate points and their corresponding wind speed data together form a "digital flow map," or spatial model, of the duct.

[0053] After obtaining the spatial model, the model data is analyzed to identify one or more "linear regions." In this embodiment, a region is considered a "linear region" if the wind speed difference between any measurement points within the region is less than 5-8 m / s. Such regions represent the most uniform and stable flow fields. The vertical depth corresponding to the linear region is determined as the optimal insertion depth of the probe assembly.

[0054] After determining the optimal insertion depth, the physical dimensions of the probe assembly need to be adjusted. Based on the target depth calculated in the previous step, the operator selects the appropriate number of pipe sections. These sections are then threaded into the connecting sleeve at the appropriate depth, connecting them one by one. Ultimately, a probe branch is assembled with a total length that precisely meets the requirements, allowing the probe to be accurately positioned within the linear area of ​​the duct.

[0055] Install the adjusted probe assembly onto the horizontal main pipe at the top of the duct, ensuring its top is connected to the main pipe and its bottom extends through the duct's ceiling. During installation, ensure the axis of the probe branch is perpendicular to the duct's axis. Once installed, the probe tip will be precisely within the previously determined linear region. Start the measurement system and obtain highly accurate and stable airflow data.

[0056] Reference Figure 3 This embodiment provides a method for measuring air volume. This embodiment is based on the previous embodiment.

[0057] There are 5 measuring holes on the air duct. Each measuring hole needs to measure the actual wind speed values ​​at 12 points. According to the wind speed of each section, the actual air volume value is calculated by taking the average value.

[0058] Air volume formula:

[0059]

[0060] Wind speed formula:

[0061]

[0062] The formula for converting wind speed into air volume is:

[0063] Q=W·ρ·F·S 3

[0064] Where Q represents the volume flow rate in T / h; W represents the wind speed in m / s; ΔP represents the output differential pressure of the measuring device in Pa; ρ represents the air density, which is calculated as ρ = 1.293 * 273 / (273 + T); T represents the wind temperature in °C; K represents the correction factor of the measuring device; F represents the cross-sectional area of ​​the pipe in m 2 , the cross-section of the air duct is: 4m*4.8m.

[0065] The specific measurement conditions are as follows:

[0066] Table 1 Wind speed data at different depths measured from top to bottom by horizontal wind box

[0067]

[0068]

[0069] Specifically, operating condition one is 360MW load, operating condition two is 500MW load, and operating condition three is 650MW load.

[0070] It can be seen that:

[0071] The locations with better wind speed for hole #1 are 1.6m deep and 2.8m deep;

[0072] The 1.6m position of hole #2 is better;

[0073] Hole #3 is at 2.4m;

[0074] Hole #4 is better at 0.8m and 2.0m;

[0075] Hole #5 is better at 1.6m and 1.2m;

[0076] At the reference wind speed position, under the same load condition, the wind speed sampled by the wind measuring probe is close to the average value, and has similar linear changes under the three load conditions of 360MW, 500MW, and 650MW.

[0077] Finally, it should be pointed out that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways without departing from the scope of the present invention.

Claims

1. An air volume measuring device, characterized in that: include, The main pipe (1) is horizontally arranged on the top of the air duct (F), and the axial direction of the main pipe (1) is perpendicular to the axial direction of the air duct (F); as well as, At least one probe assembly (2), the top of which is connected to the main pipe (1) and the bottom of which passes through the top of the air duct (F); The insertion depth of the probe assembly (2) in the air duct (F) can be adjusted according to a spatial model used to characterize the fluid dynamic field inside the air duct (F).

2. The air volume measuring device according to claim 1, characterized in that: The probe assembly (2) comprises a probe branch pipe (21) and a probe (22); the probe branch pipe (21) is arranged at the bottom of the main pipe (1); the total length of the probe branch pipe (21) can be changed; and the probe (22) is arranged at the bottom of the probe branch pipe (21).

3. The air volume measuring device according to claim 2, characterized in that: The probe branch pipe (21) is a segmented threaded connection structure, comprising at least two pipe body sections (211) and a connecting sleeve (212).

4. The air volume measuring device according to claim 3, characterized in that: The connecting end of each of the tube body sections (211) is provided with an external thread, and the inner wall of the connecting sleeve (212) is provided with an internal thread matching the external thread of the tube body section (211).

5. The air volume measuring device according to claim 2, characterized in that: The axial direction of the probe branch pipe (21) is perpendicular to the axial direction of the air duct (F) and the axial direction of the main pipe (1).

6. The air volume measuring device according to claim 1, characterized in that: The spatial model is established based on data obtained by measuring wind speed at multiple locations and depths within the wind tunnel (F).

7. The air volume measuring device according to claim 1, characterized in that: The insertion depth is within a linear region where the ends of all the probe assemblies (2) are arranged in the air duct (F).

8. The air volume measuring device according to claim 7, characterized in that: The linear region is a region where the wind speed difference is less than a preset threshold.

9. A method for measuring air volume, characterized in that: include, Establish a spatial model to characterize the fluid dynamic field inside the air duct; adjusting the insertion depth of the probe assembly into the air duct according to the spatial model; and The adjusted probe assembly is used to monitor the air duct and calculate the air volume.

10. The air volume measurement method according to claim 9, characterized in that: The steps of establishing the spatial model specifically include: The air duct is evenly divided into a plurality of spaces along a cross section perpendicular to the wind direction, and wind speed data of each space is measured; Analyzing and determining, based on the measured wind speed data, the area in the air duct where the flow field is linear; and The linear region is determined as a target adjustment region of the insertion depth of the probe assembly.

Images