Flue gas flow measuring and calibrating device for large-diameter flue

Abstract

The utility model relates to the technical field of fluid measurement, in particular to a flue gas flow measurement and calibration device for a large-diameter flue. Comprising a measuring pipe, a supporting frame, a kinetic energy conversion assembly, a calculation module and a fairing assembly, the top of the measuring pipe extends outwards to form a supporting part, the supporting part is used for abutting against the top of a flue, the supporting frame is installed in the measuring pipe, the kinetic energy conversion assembly is installed through the supporting frame, and the calculation module is installed in the measuring pipe. The kinetic energy conversion assembly is used for converting kinetic energy generated by flue gas flowing into electric energy, the calculation module is electrically connected to the electric energy output end of the kinetic energy conversion assembly, and the fairing assembly is installed on the outer side of the kinetic energy conversion assembly. According to the utility model, scheme design is carried out based on reality, kinetic energy of flue gas is converted into electric energy, the power of the generator is measured through a mathematical relation between voltage and current data and the exhaust gas flow, and then the exhaust gas flow is calculated.

Description

Technical Field

[0001] The utility model relates to the technical field of automated welding, in particular to a flue gas flow measurement and calibration device for a large-caliber flue. Background Art

[0002] Industrial production involves the measurement of numerous relatively dirty gases, such as blast furnace, converter, and coke oven gases from smelting processes, as well as their mixtures, and flue gas after desulfurization and denitrification. These gases are typically transported through large pipelines (DN400 and above), resulting in slow flow rates and uneven and unstable flow patterns, making it difficult for flow measurement devices to generate flow signals with a high signal-to-noise ratio. Furthermore, the gases are laden with impurities such as particulate matter, industrial oil mist, and water vapor, which can easily contaminate and clog flow sensors, further complicating accurate measurement. The large diameters of pipes like flues and chimneys, coupled with high flow rates, require large flowmeters, making maintenance and cleaning cumbersome, time-consuming, and labor-intensive. Disassembly and inspection are also difficult, and direct traceability to existing laboratory flow measurement standards is impossible.

[0003] To address the difficulty of laboratory calibration for flue / chimney flowmeters and atmospheric pressure large-diameter gas flowmeters, flowmeters installed in flues / chimneys / large-diameter atmospheric pressure gas pipelines can be calibrated online using a flow standard device based on the velocity-area method. Currently, there are several standard flow measurement methods based on the velocity-area method, including EPA Method 1, EPA Method 2, ISO 3966, and ISO 7194. When calibrating flowmeters installed in flues / chimneys / large-diameter atmospheric pressure gas pipelines online, a calibrated velocity meter capable of identifying velocity magnitude and direction is used to scan and measure the average flow velocity within the pipeline. Furthermore, the cross-sectional area of ​​the pipeline must be measured.

[0004] Typically, the cross-sectional area of ​​a pipe is obtained from design drawings. However, during the actual pipe manufacturing process, due to many factors such as machining accuracy, welding accuracy, stress deformation, pipe corrosion, and attached particles, the actual pipe cross-sectional area and the drawing cross-sectional size will differ, and the magnitude of this difference is difficult to determine. Alternatively, the cross-sectional area can be calculated by roughly measuring the diameter of a circular pipe or the width of a rectangular pipe from the pipe flange hole into the pipe. When using a laser rangefinder to roughly measure the diameter of a circular pipe or the width of a rectangular pipe from the flue flange hole into the flue, it is difficult to determine whether the laser is entering the flue in the diameter or width direction with a handheld instrument. Any pitch or deflection angle will cause large measurement uncertainty. Moreover, this method can only obtain a small amount of internal pipe geometric parameters and cannot obtain complete cross-sectional area information. When obtaining the cross-sectional area from the measured value, assumptions about the shape parameters must be made. Alternatively, the cross-sectional area can be calculated by measuring the external circumference of the pipe and the wall thickness. For pipes with regular cross-sectional shapes and uniform wall thickness, high-precision measuring instruments can achieve good measurement accuracy. However, if the pipe diameter is large, the cross-sectional shape is irregular, the wall thickness is uneven, or the measuring instrument is inaccurate or poorly applicable, large measurement uncertainty will be introduced. Therefore, the above cross-sectional area measurement method will cause a large measurement error, thereby affecting the accuracy of the flow measurement results of large-diameter atmospheric pressure gas pipelines such as flues or chimneys. Utility Model Content

[0005] The purpose of the utility model is to provide a flue gas flow measurement and calibration device for large-diameter flues to solve the above-mentioned problems existing in the prior art.

[0006] Technical solution: Flue gas flow measurement and calibration device for large-diameter flues, including:

[0007] The measuring tube has a top portion extending outward to form a support portion; the support portion is used to press against the top of the flue;

[0008] A support frame is installed inside the measuring tube;

[0009] A kinetic energy conversion component is installed through the support frame; the kinetic energy conversion component is used to convert the kinetic energy generated by the flow of flue gas into electrical energy;

[0010] A computing module electrically connected to the power output terminal of the kinetic energy conversion component;

[0011] The fairing assembly is installed on the outside of the kinetic energy conversion assembly.

[0012] In a further embodiment, an elastic sealing gasket is installed at the bottom of the support portion;

[0013] The elastic sealing gasket is divided into an inflation layer and a rubber layer adapted to the inflation layer.

[0014] In a further embodiment, air holes are evenly formed on the side surface of the measuring tube near the top.

[0015] In a further embodiment, the kinetic energy conversion component comprises:

[0016] at least one set of generators, wherein the generators are mounted via the support frame;

[0017] The blades are connected to the kinetic energy input end of the generator; the blades include at least two groups and are symmetrically installed about the generator.

[0018] In a further embodiment, the kinetic energy conversion components are provided in two groups, and the kinetic energy conversion components are distributed in a spiral shape with the central axis of the measuring tube as the center.

[0019] In a further embodiment, the fairing assembly comprises at least:

[0020] A head fairing is installed at the bottom of the generator; the head fairing is a spindle structure;

[0021] The tail fairing is installed on the top of the generator; the head fairing and the tail fairing are both adapted to the shape of the generator.

[0022] In a further embodiment, the outer surface of the tail fairing is streamlined, with its ends converging into a point.

[0023] In a further embodiment, the axis of the generator coincides with the axis of the measuring tube, or is symmetrical with respect to the axis of the measuring tube.

[0024] Beneficial effects

[0025] 1. To address the online calibration of flue gas flowmeters, this application independently designs a flowmeter that can be placed at flue gas outlets, such as chimneys. This device, as an online calibration device, calibrates matrix, ultrasonic, and thermal flue gas flowmeters. This device converts the kinetic energy of flue gas into electrical energy. Using the mathematical relationship between generator power and exhaust gas flow, the device measures generator power and calculates exhaust gas flow.

[0026] 2. Compared with the current measurement scheme, this application adopts a paddle-type flue gas measurement structure, and uses the measured flow rate as the standard flow rate, and compares it with the flow rate measured by the installed flue gas flow meter to calibrate the installed flue gas flow meter. This application is based on actual content for measurement, and its data is more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the working principle structure of this application.

[0028] Figure 2 It is a schematic diagram of the structure of this application.

[0029] Figure 3 It is a schematic diagram of the local structure of this application.

[0030] Figure 4 This is a schematic diagram of the blade improvement of this application.

[0031] The reference numerals in the figure are: flue 1, measuring tube 2, support frame 3, elastic sealing gasket 4, blade 5, generator 6, head fairing 7, tail fairing 8, air hole 9, inflation layer 41, rubber layer 42, support part 43. DETAILED DESCRIPTION

[0032] In the following description, numerous specific details are provided to provide a more thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention can be practiced without one or more of these details. In other instances, certain technical features known in the art are not described to avoid confusion with the present invention.

[0033] Example 1

[0034] Based on the problems mentioned in the background technology, since the smoke to measure the flow meter anti-inflammatory drugs for calibration to meet the actual engineering needs, the existing calibration accuracy is not high, that is, after the flow meter is installed, the measurement and calibration are performed indirectly through other simulation schemes, but due to many reasons such as flue processing accuracy, welding accuracy, stress deformation, pipeline corrosion and attached particles, the data indirectly obtained by the simulation scheme is unstable and not suitable as the calibration data of the flow meter in the flue. Therefore, this application is based on the actual measurement and calibration of the flue gas flow rate of the on-site chimney or flue 1 as a requirement, and designs a paddle-type flue gas flow measurement and calibration device for large-diameter flues 1, such as Figures 1 to 2 As shown, the system includes a measuring tube 2, a support frame 3, a kinetic energy conversion component, a computing module, and a fairing assembly. The measuring tube 2 is selected based on the actual flue 1, with the measuring end extending in all directions to form a support portion 43. Alternatively, a detachable annular member is used to extend the support portion 43 a second time or increase its bearing area. The support portion rests on the top of the flue 1. The kinetic energy conversion component converts the kinetic energy of the flue gas flow into electrical energy, which is used to generate voltage or current data for the computing module. The computing module then performs calculations to obtain corresponding flue gas flow data.

[0035] At the same time, a fairing assembly is installed on the outside of the kinetic energy conversion assembly to reduce the error at one time.

[0036] In this embodiment, one of the existing technical solutions for the kinetic energy conversion component and the computing module is a paddle flow meter, so other existing solutions will not be listed for further explanation in this embodiment.

[0037] When the measuring tube 2 is placed at the flue 1 opening by a crane, due to engineering errors and actual installation errors, the flue opening is not in an ideal horizontal and smooth state. Therefore, when it is placed directly, the measuring tube 2 may tilt and flue gas leakage may also occur. Therefore, it is installed through the elastic sealing gasket 4, and the elastic sealing gasket 4 is in full contact with the flue 1 opening, so that the flue gas is concentrated and passes through the measuring tube 2.

[0038] Since the elastic sealing gasket 4 is often selected with a high hardness, the measuring tube 2 may still be tilted, so the elastic sealing gasket 4 is improved, such as Figure 3 As shown, it includes an air-filled layer 41 and a rubber layer 42 wrapped around the air-filled layer 41 or connected to the rubber layer 42. With this design, the measuring tube 2 and the components inside it are always in a vertical state, which is an ideal state for measurement.

[0039] Furthermore, since there is a certain distance between the tube wall of the measuring tube 2 and the flue 1, air holes 9 are evenly opened on the side of the measuring tube 2 near the top. When the flue gas flow is large, due to the use of the elastic sealing gasket 4, the flue gas may push the measuring tube 2 upward or squeeze the tube wall of the measuring tube 2, and the measuring tube 2 will drop under its own gravity, which is prone to vertical vibration. The air holes 9 can eliminate this influence.

[0040] In this embodiment, the kinetic energy conversion assembly includes at least one set of generators 6 and blades 5, wherein the generator 6 is mounted via a support frame 3, and the blades 5 are connected to the kinetic energy input end of the generator 6. The blades include at least two sets and are symmetrically mounted about the generator 6. The axis of the generator 6 coincides with the axis of the measuring tube 2, or is symmetrical about the axis of the measuring tube 2. Similarly, the blades can also be designed as multi-stage blades, for example, Figure 4 As shown in FIG, connecting multiple blades of different diameters in series on the same axis can more effectively capture kinetic energy within various speed ranges.

[0041] Similarly, in this solution, the data measured by a group of kinetic energy conversion components may be unstable. Therefore, in a further optimization solution, the kinetic energy conversion components are set to two or more groups, and are distributed in a spiral shape with the central axis of the measuring tube 2 as the center. This design helps to balance the force and improve the energy collection efficiency.

[0042] In order to reduce the impact on the generator 6, in this embodiment, the fairing assembly includes at least a head fairing 7 and a tail fairing 8. The head fairing 7 is installed at the bottom of the generator 6. The head fairing 7 is a spindle structure. The tail fairing 8 is installed at the top of the generator 6. The head fairing 7 and the tail fairing 8 are both adapted to the shape of the generator 6. The outer surface of the tail fairing 8 is streamlined, and its ends are gathered into points.

[0043] In actual use, the paddle flowmeter is lifted to the flue 1 outlet by a ground lifting vehicle or a drone, and the device is lowered so that its flange-like edge is pressed on the edge of the flue 1 outlet. The sealing gasket in the middle prevents the gas in the flue 1 from escaping.

[0044] When the exhaust gas in the flue 1 flows through the blades located at the exhaust port of the flue 1 , the airflow drives the blades to rotate, driving the generator 6 to generate current.

[0045] Assuming that the energy of the flue gas is completely converted into electrical energy, the power of the wind turbine 6 is:

[0046] P=0.5ρAv 3 =0.5ρA 3 v 3 / A 2 =0.5Q 3 m / ρ 2 A 2

[0047] Where P represents power, ρ represents gas density, A represents flue area, v represents wind speed, Q m is the mass flow rate of flue gas.

[0048] The actual situation is that only part of the flue gas energy is converted into electrical energy, and the power mentioned above is only converted from part of the flue gas energy. Therefore, the actual electrical power obtained by the vane flowmeter can be expressed as

[0049] P=fQ 3 m / ρ 2 A 2

[0050] Where f is the flow coefficient of the vane flowmeter, and its value is obtained by calibration in a ground wind tunnel (vertical wind tunnel or horizontal wind tunnel); ρ represents the gas density.

[0051] The flow rate Qm can be obtained by measuring the power of the generator 6. The measured flow rate is used as the standard flow rate and compared with the flow meter installed on the flue 1. The relevant parameters of the installed flow meter are adjusted according to the difference.

[0052] After the online calibration is completed, the paddle flowmeter is still lifted away from the flue 1 discharge outlet using a ground lifting vehicle or a drone.

[0053] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be interpreted as limiting the present invention itself. Various changes may be made to it in form and detail without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. Flue gas flow measurement and calibration device for large-diameter flue, characterized in that: include: The measuring tube has a top portion extending outward to form a support portion; the support portion is used to press against the top of the flue; A support frame is installed inside the measuring tube; A kinetic energy conversion component is installed through the support frame; the kinetic energy conversion component is used to convert the kinetic energy generated by the flow of flue gas into electrical energy; A computing module electrically connected to the power output terminal of the kinetic energy conversion component; The fairing assembly is installed on the outside of the kinetic energy conversion assembly.

2. The flue gas flow measurement and calibration device for a large-diameter flue as claimed in claim 1, characterized in that: An elastic sealing gasket is installed at the bottom of the support portion; The elastic sealing gasket is divided into an inflation layer and a rubber layer adapted to the inflation layer.

3. The flue gas flow measurement and calibration device for a large-diameter flue as claimed in claim 1, characterized in that: The side surface of the measuring tube close to the top is evenly provided with air holes.

4. The flue gas flow measurement and calibration device for a large-diameter flue as claimed in claim 1, characterized in that: The kinetic energy conversion component includes: at least one set of generators, wherein the generators are mounted via the support frame; The blades are connected to the kinetic energy input end of the generator; the blades include at least two groups and are symmetrically installed about the generator.

5. The flue gas flow measurement and calibration device for a large-diameter flue as claimed in claim 1, characterized in that: The kinetic energy conversion components are arranged in two groups, and the kinetic energy conversion components are distributed in a spiral shape with the central axis of the measuring tube as the center.

6. The flue gas flow measurement and calibration device for a large-diameter flue as claimed in claim 4, characterized in that: The fairing assembly comprises at least: A head fairing is installed at the bottom of the generator; the head fairing is a spindle structure; The tail fairing is installed on the top of the generator; the head fairing and the tail fairing are both adapted to the shape of the generator.

7. The flue gas flow measurement and calibration device for a large-diameter flue as claimed in claim 6, characterized in that: The outer surface of the tail fairing is streamlined, and the ends thereof are gathered into a point.

8. The flue gas flow measurement and calibration device for a large-diameter flue as claimed in claim 4, characterized in that: The axis of the generator coincides with the axis of the measuring tube, or is symmetrical with respect to the axis of the measuring tube.

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