Air pipeline flow measuring device and calibration assembly thereof

Abstract

The utility model discloses an air pipeline flow measuring device and a calibration assembly thereof, and relates to the technical field of flow detection. The calibration assembly comprises a first pressure source, a flow sensor, a first gas collection container and a calibration pipeline which are connected in sequence; wherein the first pressure source is used for providing compressed gas; the first gas collection container is used for storing compressed gas from the first pressure source; the flow sensor is used for measuring the flow of air flowing to the calibration pipeline; the total pressure sensor, the static pressure sensor and the temperature sensor can be installed on the calibration pipeline. Through the arrangement of the first pressure source and the first gas collection container, the first pressure source can convey compressed gas to the first gas collection container. Namely, the first gas collection container can play a buffering role, and even if the pressure of the compressed gas generated by the first pressure source is unstable, the compressed gas input into the calibration pipeline after passing through the first gas collection container can also ensure that the pressure is stable.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of flow detection, in particular to an air pipeline flow measuring device and a calibration assembly thereof. BACKGROUND

[0002] In general, a large number of pipelines are used for air system in aero derivative gas turbine (a type of gas turbine), and in the design and test of the aero derivative gas turbine air system, it is crucial to accurately obtain the air flow in the pipeline for adjusting the thermal cycle parameters and the hot end component cooling parameters of the designed gas turbine. However, the air flow in each pipeline of the aero derivative gas turbine after installation cannot be accurately measured by sensors and other devices, and in order to obtain the air flow in each pipeline of a certain type of aero derivative gas turbine, only indirect calculation and evaluation can be performed. The commonly used pipeline flow calibration method in the field of gas turbines is the conversion flow method, for example, the patent document with the publication number CN110206596A discloses a similar method, which mainly obtains the air amount participating in combustion and the air amount participating in cooling in the gas turbine by converting the total amount of fuel, the total amount of air and the total amount of exhaust gas input into the gas turbine. Although this method can accurately estimate the air amount participating in combustion and the air amount participating in cooling in the gas turbine, it cannot estimate the air flow in each pipeline, for example, it cannot estimate the air flow in the compressor cooling pipeline and the air flow in the turbine blade cooling pipeline. In order to solve this technical problem, the application proposes a measuring device cooperating with the test method to accurately measure the air flow in each pipeline of the gas turbine (detailed method see below). However, the measuring method of the application needs to use the calibration assembly to pre-acquire the pressure ratio flow coefficient characteristic function corresponding to the measuring device. The calibration assembly (for example, a gas turbine with known air flow in each pipeline) of the prior art is difficult to accurately obtain the pressure ratio flow coefficient characteristic function of the measuring device because the output compressed air pressure is unstable. If the accuracy of the pressure ratio flow coefficient characteristic function is poor, the accuracy of the subsequent evaluation of the air flow in each pipeline is also poor. CONTENT OF THE UTILITY MODEL

[0003] The application aims to provide an air pipeline flow measuring device and a calibration assembly thereof to solve the technical problem that the existing calibration assembly is difficult to stably control the pressure of compressed gas.

[0004] To achieve the above-mentioned purpose, the application provides the following technical solutions:

[0005] In a first aspect, the application provides a calibration assembly applied to an air pipeline flow measuring device, the measuring device comprising at least a total pressure sensor, a static pressure sensor and a temperature sensor, the calibration assembly being used to provide compressed gas to at least the total pressure sensor, the static pressure sensor and the temperature sensor; the calibration assembly comprising a first pressure source, a flow sensor, a first gas storage container and a calibration pipeline connected in sequence; wherein the first pressure source is used to provide compressed gas; the first gas storage container is used to store compressed gas from the first pressure source; the flow sensor is used to measure the air flow to the calibration pipeline; and the total pressure sensor, the static pressure sensor and the temperature sensor can be installed on the calibration pipeline.

[0006] As a specific solution in the application, the calibration assembly further comprises a heater, which is arranged between the first pressure source and the calibration pipeline.

[0007] As a specific solution in the application, the calibration assembly further comprises a first control valve, which is arranged between the first pressure source and the calibration pipeline.

[0008] As a specific solution in the application, the calibration assembly further comprises a second pressure source and a second gas storage container, the outlet of the second pressure source and the calibration pipeline are both communicated with the second gas storage container; and the second gas storage container is provided with a gas discharge opening.

[0009] As a specific solution in the application, the calibration assembly further comprises a second control valve, which is arranged between the second gas storage container and the second pressure source.

[0010] In a second aspect, the application provides an air pipeline flow measuring device, which comprises:

[0011] The calibration assembly according to any one of the first aspect;

[0012] a total pressure sensor, which is used to measure at least a first air total pressure in the air pipeline;

[0013] a static pressure sensor, which is used to measure at least a first air static pressure in the air pipeline;

[0014] a temperature sensor, which is used to measure at least a first air temperature in the air pipeline.

[0015] As a specific solution in the application, the total pressure sensor comprises:

[0016] a first differential pressure transmitter;

[0017] The first pressure tube has a first end connected to the first differential pressure transmitter, and a second end used to extend into the interior of the air pipeline during use, and an end face of the second end of the first pressure tube faces the air in the air pipeline; a first normal line of the end face of the second end of the first pressure tube is parallel to the axial line of the air pipeline.

[0018] As a specific solution in the technical scheme of the application, the static pressure sensor comprises:

[0019] The second differential pressure transmitter;

[0020] The second pressure tube has a first end connected to the second differential pressure transmitter, and a second end used to extend into the interior of the air pipeline during use, and an end face of the second end of the second pressure tube faces away from the air in the air pipeline; a second normal line of the end face of the second end of the second pressure tube is parallel to the axial line of the air pipeline.

[0021] Compared with the prior art, the application has the beneficial effects that:

[0022] The first pressure source can deliver compressed gas to the first gas collecting container, that is, the first gas collecting container can play a buffering role, and even if the compressed gas pressure generated by the first pressure source is unstable, the compressed gas input into the calibration pipeline can also ensure stable pressure after passing through the first gas collecting container. That is, in the application, the setting of the first gas collecting container can ensure the stable pressure of the compressed gas in the calibration pipeline. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 A structural schematic diagram of a measuring device according to an embodiment of the application;

[0024] Figure 2 A sectional view schematic diagram of an air pipeline on which a measuring device according to an embodiment of the application is installed;

[0025] Figure 3 A sectional view schematic diagram of an air pipeline on which a measuring device according to an embodiment of the application is installed; Figure 2 An enlarged view of part B in FIG. 8;

[0026] Figure 4 A schematic diagram of an installation position of a measuring device according to an embodiment of the application on an air pipeline with a bent pipe;

[0027] Figure 5 A schematic diagram of a curve formed by a pressure ratio flow coefficient characteristic function according to an embodiment of the application;

[0028] Figure 6A flow chart of a gas turbine air pipeline flow measurement method according to an embodiment of the present application.

[0029] In the figure: 1, first pressure source; 2, first control valve; 3, heater; 4, flow sensor; 5, first gas collecting container; 6, calibration pipeline; 61, total pressure sensor; 611, first differential pressure transmitter; 612, first pressure measuring pipe; 613, first normal line; 62, static pressure sensor; 621, second differential pressure transmitter; 622, second pressure measuring pipe; 623, second normal line; 63, temperature sensor; 64, axial line; 7, second gas collecting container; 8, second control valve; 9, second pressure source; 10, air pipeline; 101, elbow. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work belong to the scope of protection of the present application.

[0031] It should be noted that, in the description of the present application, the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application and simplify the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0032] In addition, it should be understood that, for the convenience of description, the sizes of the various components shown in the drawings are not drawn in accordance with the actual proportional relationship, for example, the thickness or width of certain layers can be exaggerated relative to other layers.

[0033] It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once an item is defined or described in one drawing, it will not need to be further specifically discussed and described in the description of subsequent drawings.

[0034] In order to solve the technical problem that the existing calibration assembly is difficult to stably control the pressure of compressed gas as proposed in the background art, an embodiment of a calibration assembly is proposed in the present application, which is applied to an air pipeline flow measurement device. As shown in Figure 1 and Figure 2As shown, the measuring device at least includes a total pressure sensor 61, a static pressure sensor 62 and a temperature sensor 63, and the calibration assembly is at least used to provide compressed gas to the total pressure sensor 61, the static pressure sensor 62 and the temperature sensor 63. Specifically, as shown in the figure, the calibration assembly can include a first pressure source 1, a flow sensor 4, a first gas storage container 5 and a calibration pipeline 6 connected in sequence. The first pressure source 1 is used to provide compressed gas. The first gas storage container 5 is used to store compressed gas from the first pressure source 1. The flow sensor 4 is used to measure the air flow to the calibration pipeline 6. The total pressure sensor 61, the static pressure sensor 62 and the temperature sensor 63 can be installed on the calibration pipeline 6. Figure 1 As shown, the calibration assembly can include a first pressure source 1, a flow sensor 4, a first gas storage container 5 and a calibration pipeline 6 connected in sequence. The first pressure source 1 is used to provide compressed gas. The first gas storage container 5 is used to store compressed gas from the first pressure source 1. The flow sensor 4 is used to measure the air flow to the calibration pipeline 6. The total pressure sensor 61, the static pressure sensor 62 and the temperature sensor 63 can be installed on the calibration pipeline 6.

[0035] It should be noted that the first pressure source 1 can be any device capable of providing compressed gas (the same applies to the second pressure source 9 below, which will not be described in detail hereinafter), for example, the first pressure source 1 can be an air tank storing compressed gas, or the first pressure source 1 can be a compressor capable of generating compressed gas, etc. The calibration pipeline 6 can be a straight pipe with uniform inner diameter, or a bent pipe with uniform inner diameter, etc.

[0036] It should be noted that in the embodiments of the present application, the compressed gas can be any suitable gas, for example, compressed nitrogen, compressed oxygen or compressed carbon dioxide, etc. Since the embodiments listed in the present application are the application scenarios of the gas turbine air pipeline, the compressed gas in the present embodiment can be compressed air. In the following embodiments, compressed air is taken as an example to illustrate the compressed gas, which will not be described in detail hereinafter.

[0037] In the embodiments, the pressure ratio flow coefficient characteristic function of the measuring device is obtained based on the calibration assembly, including steps S110 to S140.

[0038] Step S110: Based on the first pressure source 1, the compressed air with a preset pressure is delivered to the inlet of the calibration pipeline 6.

[0039] It should be noted that delivering compressed air with a preset pressure from a pressure source (such as a compressor or an air tank, etc.) to the calibration pipeline is a mature technology, which will not be described in detail hereinafter.

[0040] Step S120: Based on the flow sensor 4, the second air flow input into the calibration pipeline 6 is obtained.

[0041] It should be noted that obtaining the air flow in the calibration pipeline through the flow sensor is a mature technology, which will not be described in detail hereinafter.

[0042] Step S130: Based on the measuring device, the second air total pressure, the second air static pressure and the second air temperature of the calibration pipeline 6 are obtained.

[0043] It should be noted that the measuring device proposed in this application embodiment can measure the total air pressure, static air pressure, and air temperature of the pipeline under test (e.g., calibration pipeline 6 and air pipeline 10). Specific measurement methods can be found in steps S200 to S400 below, and will not be elaborated here.

[0044] Step S140: Based on the second total air pressure, the second static air pressure, the second air temperature, and the second air flow rate, obtain the pressure ratio flow rate coefficient characteristic function.

[0045] As can be seen from the foregoing, in this embodiment, as Figure 5 As shown, first obtain multiple coordinate points, the coordinates of each point being (π / 2). i μ i ), where π i μ represents the x-coordinate of the i-th coordinate point (i.e., the pressure ratio measured each time). i This represents the ordinate of the i-th coordinate point (i.e., the flow coefficient for each measurement).

[0046] Specifically, in the embodiments of this application, the formula for calculating the x-coordinate of each coordinate point is as follows:

[0047] π i =P i * / P i

[0048] Where, π i P represents the x-coordinate of the point in the i-th measurement; i * P represents the total air pressure measured in the i-th measurement (i.e., the second total air pressure measured in the i-th measurement); i This represents the static air pressure measured in the i-th measurement (which is also the second static air pressure measured in the i-th measurement).

[0049] Specifically, in the embodiments of this application, the formula for calculating the ordinate of each coordinate point is as follows:

[0050]

[0051] Where, μ i G represents the ordinate of the coordinate point in the i-th measurement; i T represents the airflow rate measured in the i-th measurement (i.e., the second airflow rate measured in the i-th measurement); i P represents the air temperature measured in the i-th measurement (i.e., the second air temperature measured in the i-th measurement); i *Ptotai(i) represents the total pressure of air of the i-th measurement (i.e. the second total pressure of air of the i-th measurement); K represents a first related parameter of the gas dynamics function; q(λ) represents a second related parameter of the gas dynamics function; A represents the radial flow area of the pipeline to be measured (i.e. the calibration pipeline 6).

[0052] Specifically, in the embodiment of the present application, the calculation formula of the first related parameter K is as follows:

[0053]

[0054] wherein K represents the first related parameter of the gas dynamics function; r represents the specific heat ratio of air, generally taking 1.40; R represents the gas constant of air, generally taking 287.1 J / (kg*k).

[0055] Specifically, in the embodiment of the present application, the calculation formula of the second related parameter q(λ) is as follows:

[0056]

[0057] wherein q(λ) represents the second related parameter of the gas dynamics function; r represents the specific heat ratio of air, generally taking 1.40; λ i represents the velocity factor of the i-th measurement.

[0058] Specifically, in the embodiment of the present application, the calculation formula of the velocity factor λ i is as follows:

[0059]

[0060] wherein λ i represents the velocity factor of the i-th measurement; r represents the specific heat ratio of air, generally taking 1.40; π i represents the abscissa of the coordinate point of the i-th measurement (i.e. the pressure ratio of the i-th measurement).

[0061] It should be noted that fitting multiple coordinate points to obtain a fitting function (i.e. a pressure ratio flow coefficient characteristic function) is a mature technology, which will not be described here. It should be clear that the embodiment of the present application enables the user to easily obtain the pressure ratio flow coefficient characteristic function of the measuring device by means of the calibration assembly.

[0062] It should be noted that in the process of calibrating the pressure ratio flow coefficient characteristic function of the measuring device by means of the calibration assembly, the higher the accuracy of each coordinate point obtained, the higher the accuracy of the pressure ratio flow coefficient characteristic function obtained. It is easy to understand that the more stable the pressure of air in the calibration pipeline 6, the higher the accuracy of each coordinate point obtained. In the present embodiment, as Figure 1As shown, in use, the first pressure source 1 delivers compressed air to the first air collecting container 5. The first air collecting container 5 can play a buffering role, even if the compressed air pressure generated by the first pressure source 1 is unstable, after passing through the first air collecting container 5, the compressed air pressure input into the calibration pipeline 6 can be ensured to be stable. That is, in this embodiment, through the setting of the first air collecting container 5, the pressure of the air in the calibration pipeline 6 can be ensured to be stable.

[0063] In this embodiment, the first pressure source 1 can also be any device capable of generating compressed air. For example, the first pressure source 1 can be a compressor or a compressor, etc. In order to ensure that the compressed air pressure generated by the first pressure source 1 is stable enough, in this embodiment, the first pressure source 1 can be a compressor capable of stabilizing the pressure.

[0064] It should be noted that in the process of fitting to obtain the pressure ratio flow coefficient characteristic function of the measuring device, the greater the difference in coordinate values of each coordinate point, the higher the accuracy of the pressure ratio flow coefficient characteristic function obtained, and the higher the accuracy of the subsequent air flow in each pipeline of the gas turbine obtained by using the pressure ratio flow coefficient characteristic function. In order to facilitate the adjustment of the air temperature in the calibration pipeline 6, in order to easily obtain coordinate points with large coordinate value differences, and thus improve the accuracy of the pressure ratio flow coefficient characteristic function of the measuring device obtained subsequently. In an embodiment of the present application, the calibration assembly can also include a heater 3, which is arranged between the first pressure source 1 and the calibration pipeline 6. The heater 3 is at least used to control the temperature of the air in the calibration pipeline 6. Figure 1

[0065] It should be noted that the temperature of the air flowing to the calibration pipeline 6 can be adjusted by the heater 3. As known from the foregoing, if other conditions (air pressure and air flow rate, etc.) remain unchanged, if the temperature difference of the air in the calibration pipeline 6 is large, the coordinate value difference between the subsequent obtained coordinate points is also large.

[0066] It should be noted that in the process of fitting to obtain the pressure ratio flow coefficient characteristic function of the measuring device, the more the number of coordinate points, the higher the accuracy of the pressure ratio flow coefficient characteristic function obtained, and the higher the accuracy of the subsequent air flow in each pipeline of the gas turbine obtained by using the pressure ratio flow coefficient characteristic function. In order to be able to obtain as many coordinate points as possible, in the embodiments of the present application, the first pressure source 1 with different air pressures can be replaced. In order to be able to adjust the pressure of the air input into the calibration pipeline 6 in the application scenario with only one first pressure source 1, in an embodiment of the present application, the calibration assembly can also include a heater 3, which is arranged between the first pressure source 1 and the calibration pipeline 6. The heater 3 is at least used to control the temperature of the air in the calibration pipeline 6. Figure 1 ​As shown, the calibration assembly may further include a first control valve 2, which is disposed between the first pressure source 1 and the calibration line 6. The first control valve 2 is used at least to control the air pressure at the inlet of the calibration line 6.

[0067] In the embodiments of this application, the first control valve 2 can be any valve capable of adjusting the pipeline opening (the same applies to the second control valve 8 mentioned below, which will not be elaborated further), such as a butterfly valve or a ball valve. It is easy to understand that by adjusting the pipeline opening through the first control valve 2, the amount of air entering the calibration pipeline 6 can be adjusted, that is, the air pressure at the inlet of the calibration pipeline 6 can be adjusted.

[0068] To further stabilize the air pressure in the calibration pipeline 6, in one embodiment of this application, the calibration assembly may further include a second pressure source 9 and a second gas collection container 7. The outlets of both the second pressure source 9 and the calibration pipeline 6 are connected to the second gas collection container 7, which is provided with a venting opening.

[0069] In this embodiment, as Figure 1 As shown, the first gas collecting container 5 can ensure the stability of the air pressure at the inlet of the calibration pipeline 6, and the second gas collecting container 7 can ensure the stability of the pressure at the outlet of the calibration pipeline 6. It is easy to understand that if both the inlet and outlet pressures of the calibration pipeline 6 can be stable, then the air pressure difference inside the calibration pipeline 6 can be stable, that is, the air pressure at all points inside the calibration pipeline 6 can be stable.

[0070] In order to adjust the air pressure at the outlet of calibration line 6 and thus adjust the air pressure difference inside calibration line 6, in one embodiment of this application, the calibration assembly may further include a second control valve 8, which is disposed between the second air collection container 7 and the second pressure source 9. Figure 1 As shown, in this embodiment, the opening degree of the second control valve 8 can be adjusted to create different air pressure differences inside the calibration pipeline 6.

[0071] It is important to understand that the embodiments of the calibration components proposed in this application, through the arrangement of a first pressure source and a first gas collecting container, enable the first pressure source to deliver compressed gas to the first gas collecting container. That is, the first gas collecting container acts as a buffer, ensuring that even if the pressure of the compressed gas generated by the first pressure source is unstable, the pressure of the compressed gas entering the calibration pipeline remains stable after passing through the first gas collecting container. In other words, the embodiments of this application, through the arrangement of the first gas collecting container, ensure the pressure stability of the compressed gas in the calibration pipeline.

[0072] After introducing the embodiment of the calibration assembly proposed in the present application, the following introduces an embodiment of an air pipeline flow measuring device proposed in the present application. Specifically, the air pipeline flow measuring device comprises a total pressure sensor 61, a static pressure sensor 62, a temperature sensor 63, and the calibration assembly proposed in any one of the above embodiments. The total pressure sensor 61 is at least used to measure the first air total pressure in the air pipeline. The static pressure sensor 62 is at least used to measure the first air static pressure in the air pipeline. The temperature sensor 63 is at least used to measure the first air temperature in the air pipeline.

[0073] Specifically, the air pipeline flow measuring device is used to measure the air flow of the air pipeline, comprising steps S100 to S500.

[0074] Step S100: obtaining the pressure ratio flow coefficient characteristic function of the measuring device based on the calibration assembly.

[0075] It should be noted that through the long-term research of the inventor, it is found that the pressure ratio (i.e. the ratio of the air total pressure to the air static pressure in the pipeline to be measured) of the pipeline to be measured (for example, the calibration pipeline 6 and the air pipeline 10 in the present application, etc.) tested by the measuring device and the air temperature in the pipeline to be measured and the actual flow of the air in the pipeline to be measured are in a linear relationship, that is, the pressure ratio of the pipeline to be measured is in a linear relationship with the flow coefficient in the above. For example, as shown in Figure 5 , Figure 5 a curve formed by the pressure ratio flow coefficient characteristic function of the measuring device proposed in the embodiment of the present application, wherein the abscissa is the pressure ratio and the ordinate is the flow coefficient. That is, in the embodiment of the present application, if the pressure ratio flow coefficient characteristic function of the measuring device can be obtained, the first air flow of the air pipeline 10 can be measured based on the pressure ratio flow coefficient characteristic function and by means of the measuring device as described below.

[0076] In the embodiment of the present application, the pressure ratio flow coefficient characteristic function of the measuring device can be obtained based on any reasonable manner based on the calibration assembly. For example, in one embodiment of the present application, the measuring device can be directly installed in various gas turbines with known flow (i.e. the calibration assembly), and then a large number of experiments are performed, and the pressure ratio flow coefficient characteristic function of the measuring device is obtained based on a large number of experimental data according to experience. The pressure ratio flow coefficient characteristic function of the measuring device can also be obtained based on the steps S110 to S140 in the above.

[0077] Step S200: obtaining the first air total pressure of the air pipeline 10 based on the total pressure sensor 61.

[0078] It should be clear that the pressure sensor (i.e. the total pressure sensor) is arranged in the air pipeline to obtain the air total pressure in the air pipeline, which is a mature technology and will not be described here.

[0079] Step S300: Based on the static pressure sensor 62, obtain the first static air pressure of the air pipeline 10.

[0080] It is important to understand that placing a pressure sensor (i.e., a static pressure sensor) in an air pipeline to obtain the static pressure of the air in the pipeline is a mature technology, which will not be elaborated here.

[0081] Step S400: Based on temperature sensor 63, obtain the first air temperature of air duct 10.

[0082] It should be noted that placing temperature sensors in air ducts to obtain the air temperature in the air ducts is a mature technology, which will not be elaborated here.

[0083] Step S500: Based on the first total air pressure, the first static air pressure, and the first air temperature, the first air flow rate of the air pipeline 10 is obtained by the pressure ratio flow coefficient characteristic function of the measuring device.

[0084] Specifically, in the embodiments of this application, based on the first total air pressure, the first static air pressure, and the first air temperature, the calculation formula for the first air flow rate of the air pipeline 10 is obtained from the pressure ratio flow coefficient characteristic function of the measuring device as follows:

[0085]

[0086] Among them, G m denoted by m, the air flow rate of air pipe 10 is measured for the mth time (i.e., the first air flow rate measured for the mth time); K represents the first relevant parameter of the gas dynamics function, and its calculation formula is the same as above; q(λ) represents the second relevant parameter of the gas dynamics function, and its calculation formula is the same as above; A represents the runoff area of ​​the pipe to be measured (i.e., air pipe 10); T represents the total air pressure of air line 10 measured in the m-th measurement (i.e., the first total air pressure measured in the m-th measurement); m This represents the air temperature of air pipe 10 measured in the m-th measurement (i.e., the first air temperature measured in the m-th measurement); μ m The flow coefficient of air line 10 is represented by the m-th measurement, which is obtained based on the pressure ratio flow coefficient characteristic function.

[0087] In the embodiments of the present application, the total pressure sensor 61 can be any sensor capable of measuring the total pressure of the air in the pipeline on the market. For example, the total pressure sensor 61 can be a pressure sensor disclosed in the patent documents with publication numbers CN214748114U or CN104101457A. It should be noted that most of the total pressure sensors in the prior art have complex structures and high manufacturing costs. In order to reduce the use cost, in an embodiment of the present application, the total pressure sensor 61 can include a first differential pressure transmitter 611 and a first pressure measuring tube 612. In use, as shown in Figure 2 , the first end of the first pressure measuring tube 612 is connected to the first differential pressure transmitter 611, the second end of the first pressure measuring tube 612 extends to the inside of the air pipeline 10, and the end face of the second end of the first pressure measuring tube 612 faces the air in the air pipeline 10 (the flow direction of the air in the air pipeline 10 is shown as direction A in Figure 2 ), and the first normal line 613 of the end face of the second end of the first pressure measuring tube 612 is parallel to the axis line 64 of the air pipeline 10.

[0088] It should be noted that the air will form friction with the inner wall of the pipeline during the flow in the pipeline. That is, in the air pipeline 10, the closer to the inner wall of the air pipeline 10 along the radial direction of the air pipeline 10, the smaller the pressure of the air at this position. In order to accurately obtain the total pressure of the air in the air pipeline 10, as shown in Figure 3 , the distance between the second end of the first pressure measuring tube 612 and the air pipeline 10 (i.e. the distance H as shown in Figure 3 ) can be greater than or equal to the outer diameter of the first pressure measuring tube 612. It should also be noted that, as shown in Figure 2 , if the distance between the second end of the first pressure measuring tube 612 and the air pipeline 10 is too large, that is, the more the first pressure measuring tube 612 is inserted into the air pipeline 10, the first pressure measuring tube 612 will affect the flow of the air in the air pipeline 10. If the flow of the air in the air pipeline 10 is affected, the measurement accuracy of the total pressure of the air in the air pipeline 10 will be affected. In order to further obtain the accurate total pressure of the air in the air pipeline 10, in the embodiments of the present application, the distance between the second end of the first pressure measuring tube 612 and the air pipeline 10 (i.e. the distance H as shown in Figure 3 ) can be less than or equal to 1 / 2 of the outer diameter of the air pipeline 10.

[0089] It is easy to understand that in the following in order to accurately obtain the static pressure of the air in the air pipeline 10, in the embodiments of the present application, the distance between the second end of the second pressure measuring tube 622 and the air pipeline 10 can be greater than or equal to the outer diameter of the second pressure measuring tube 622, and less than or equal to 1 / 2 of the outer diameter of the air pipeline 10. For specific principles, please refer to the above, which will not be repeated here.

[0090] In the embodiments of the present application, the static pressure sensor 62 can be any sensor on the market that can measure the total pressure of the air in the pipeline. For example, the static pressure sensor 62 can be the pressure sensor disclosed in the patent documents with publication numbers CN216868209U or CN205940861U. It should be noted that most of the static pressure sensors in the prior art have complex structures and high manufacturing costs. In order to reduce the use cost, in an embodiment of the present application, the static pressure sensor 62 can include a second differential pressure transmitter 621 and a second pressure measuring tube 622. In use, as shown in Figure 2 , the first end of the second pressure measuring tube 622 is connected to the second differential pressure transmitter 621, the second end of the second pressure measuring tube 622 extends to the inside of the air pipeline 10, and the end face of the second end of the second pressure measuring tube 622 faces away from the air in the air pipeline 10 (the flow direction of the air in the air pipeline 10 is shown as direction A in Figure 2 ), the second normal line 623 of the end face of the second end of the second pressure measuring tube 622 is parallel to the axis line 64 of the air pipeline 10.

[0091] It should be clear that in the flow process of the air, if there is a bend, the total pressure and the static pressure of the air at the bend are greatly disturbed, that is, if the measuring device is arranged at the bend, it is difficult to obtain accurate total pressure and static pressure of the air. In order to further obtain accurate total pressure and static pressure of the air in the air pipeline 10, after a large number of experimental verifications by the inventors, in the embodiments of the present application, if the air pipeline 10 has a bend 101, and along the flow direction of the air in the air pipeline 10 (that is, the flow path F as shown in Figure 4 ), the measuring device is located before the bend 101 (for example, the position C1 as shown in Figure 4 ), the distance between the measuring device and the bend 101 (that is, the distance S1 as shown in Figure 4 ) can be greater than or equal to twice the outer diameter of the air pipeline 10. If the air pipeline 10 has a bend 101, and along the flow direction of the air in the air pipeline 10 (that is, the flow path F as shown in Figure 4 ), the measuring device is located after the bend 101 (for example, the position C2 as shown in Figure 4 ), the distance between the measuring device and the bend 101 (that is, the distance S2 as shown in Figure 4 ) can be greater than or equal to six times the outer diameter of the air pipeline 10.

[0092] It should be noted that the embodiment of the air pipeline flow measuring device provided in the present application is provided with the first pressure source and the first gas collecting container, so that the first pressure source can deliver compressed gas to the first gas collecting container. That is, the first gas collecting container can play a buffering role, and even if the pressure of the compressed gas generated by the first pressure source is unstable, the pressure of the compressed gas input into the calibration pipeline after passing through the first gas collecting container can be ensured to be stable. That is, the embodiment of the present application can ensure the stability of the pressure of the compressed gas in the calibration pipeline through the provision of the first gas collecting container.

[0093] Although the embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made thereto without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A calibration assembly applied to an air pipeline flow measuring device, the measuring device comprising at least a total pressure sensor (61), a static pressure sensor (62) and a temperature sensor (63), the calibration assembly being used at least to supply compressed gas to the total pressure sensor (61), the static pressure sensor (62) and the temperature sensor (63); characterized in that, The calibration assembly comprises a first pressure source (1), a flow sensor (4), a first gas collecting container (5) and a calibration pipeline (6) connected in sequence; wherein the first pressure source (1) is used for providing compressed gas; the first gas collecting container (5) is used for storing compressed gas from the first pressure source (1); the flow sensor (4) is used for measuring the air flow to the calibration pipeline (6); the total pressure sensor (61), the static pressure sensor (62) and the temperature sensor (63) can be installed on the calibration pipeline (6).

2. The calibration assembly of claim 1, wherein, The calibration assembly further comprises a heater (3) arranged between the first pressure source (1) and the calibration pipeline (6).

3. The calibration assembly of claim 1, wherein, The calibration assembly further comprises a first control valve (2) arranged between the first pressure source (1) and the calibration pipeline (6).

4. The calibration assembly of any one of claims 1 to 3, wherein, The calibration assembly further comprises a second pressure source (9) and a second gas collecting container (7), the outlet of the second pressure source (9) and the calibration pipeline (6) are both communicated with the second gas collecting container (7); the second gas collecting container (7) is provided with a gas discharge opening.

5. The calibration assembly of claim 4, wherein, The calibration assembly further comprises a second control valve (8) arranged between the second gas collecting container (7) and the second pressure source (9).

6. An apparatus for measuring the flow of air in an air line, comprising: Comprise: The calibration assembly according to any one of claims 1 to 5; A total pressure sensor (61) used for at least measuring the first air total pressure in the air pipeline; A static pressure sensor (62) used for at least measuring the first air static pressure in the air pipeline; A temperature sensor (63) used for at least measuring the first air temperature in the air pipeline.

7. The apparatus of claim 6, wherein The total pressure sensor (61) comprises: A first differential pressure transmitter (611); A first pressure measuring tube (612); the first end of the first pressure measuring tube (612) is connected with the first differential pressure transmitter (611); in use, the second end of the first pressure measuring tube (612) is used to extend to the inside of the air pipeline, and the end face of the second end of the first pressure measuring tube (612) faces the air in the air pipeline; the first normal line (613) of the end face of the second end of the first pressure measuring tube (612) is parallel to the axis line (64) of the air pipeline.

8. The apparatus for measuring flow of air conduit according to claim 7, wherein, The static pressure sensor (62) comprises: A second differential pressure transmitter (621); A second pressure measuring tube (622); the first end of the second pressure measuring tube (622) is connected with the second differential pressure transmitter (621); in use, the second end of the second pressure measuring tube (622) is used to extend to the inside of the air pipeline, and the end face of the second end of the second pressure measuring tube (622) faces away from the air in the air pipeline; the second normal line (623) of the end face of the second end of the second pressure measuring tube (622) is parallel to the axis line (64) of the air pipeline.

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