Flow measurement calibration device and calibration method thereof

Abstract

The application discloses a flow measurement calibration device and a calibration method thereof, relates to the technical field of flow measurement equipment, and comprises an air inlet system, a calibration system, a comparison system, a first flow tube calibration system and a second flow tube calibration system. The air inlet system, the calibration system and the comparison system are sequentially connected, the first flow tube calibration system and the second flow tube calibration system are arranged in parallel at the output end of the comparison system, the calibration system comprises a pressure stabilizing tank, a gas collecting tank and a calibration pipeline, the air inlet system is communicated to the pressure stabilizing tank, the calibration pipeline is provided with a plurality of calibration pipelines, the input ends of the plurality of calibration pipelines are communicated to the pressure stabilizing tank, the output ends of the plurality of calibration pipelines are communicated to the gas collecting tank, and the calibration pipeline is sequentially provided with a ball valve, a measurement assembly, a Venturi nozzle and a ball valve from the input end to the output end. The present scheme can realize horn mouth type flow tube calibration and classical Venturi tube calibration.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flow measurement devices, in particular to a flow measurement calibration device and a calibration method based on the device. BACKGROUND

[0002] Critical flow Venturi nozzle (referred to as sound speed nozzle) is a differential pressure flowmeter with an inlet tapering to a throat and then expanding to an outlet, including a contraction section, a throat and a diffusion section. The sound speed nozzle is widely used as a transfer standard for other types of gas flowmeters at home and abroad due to its simple structure, no movable parts, high accuracy, good repeatability and other characteristics. At the same time, the sound speed nozzle can be directly traced to the national gas flow primary standard device. Therefore, the sound speed nozzle occupies an important position in the gas flow value traceability system and is a key link to ensure the accuracy and reliability of gas flow measurement and value unification.

[0003] The existing flow calibration device has a short cycle for critical flow Venturi nozzle periodic verification, and the disassembly and primary calibration workload is large, thereby increasing the maintenance cost of the equipment. SUMMARY

[0004] The present application aims to overcome the shortcomings of the prior art and provide a flow measurement calibration device and a calibration method thereof.

[0005] A flow measurement calibration device comprises

[0006] An air intake system: introducing high-pressure gas and adjusting the flow of input high-pressure gas;

[0007] A calibration system: using a critical flow Venturi nozzle to test and calibrate the input gas;

[0008] A comparison system: calibrating the calibration system;

[0009] A first flow tube calibration system: used for calibrating a horn mouth type flow tube;

[0010] A second flow tube calibration system: used for calibrating a classical Venturi tube type flowmeter;

[0011] The air intake system, calibration system and comparison system are connected in sequence, the first flow tube calibration system and the second flow tube calibration system are arranged in parallel at the output end of the comparison system, the calibration system comprises a pressure stabilizing tank, a gas collecting tank and calibration pipelines, the air intake system is connected to the pressure stabilizing tank, the calibration pipelines are provided in plurality, the input ends of the plurality of calibration pipelines are connected to the pressure stabilizing tank, the output ends of the plurality of calibration pipelines are connected to the gas collecting tank, and the calibration pipelines are sequentially provided with ball valves, measurement assemblies, Venturi nozzles and ball valves from the input ends to the output ends.

[0012] Further, the several calibration pipelines are divided into three groups, the first group of calibration pipelines and the second group of calibration pipelines are respectively provided with 11 branches, and the third group of calibration pipelines is provided with 22 branches.

[0013] Further, the throat diameter of the Venturi nozzle in the first group of calibration pipelines is 7mm-9mm; the throat diameter of the Venturi nozzle in the second group of calibration pipelines is 7mm-9mm; and the throat diameter of the Venturi nozzle in the third group of calibration pipelines is 22mm-24mm.

[0014] Further, the measurement assembly comprises a temperature measuring instrument and a pressure measuring instrument.

[0015] Further, the temperature measuring instrument is provided with two, and the two temperature measuring instruments are respectively arranged at both ends of the Venturi nozzle.

[0016] Further, the comparison system comprises a stagnation container, a backflow pipe and a comparison pipeline, the calibration system is communicated to the stagnation container, the comparison pipeline is provided with several, the input end of the several comparison pipelines is communicated to the stagnation container, and the output end of the several comparison pipelines is communicated to the backflow pipe.

[0017] Further, each comparison pipeline is sequentially provided with a Venturi nozzle, a pressure measuring instrument and a valve from the input end to the output end.

[0018] Further, the several comparison pipelines are divided into four groups,

[0019] The first group of comparison pipelines is provided with 1 branch, and the throat diameter of the Venturi nozzle in the first group of comparison pipelines is 11mm-12mm;

[0020] The second group of comparison pipelines is provided with 1 branch, and the throat diameter of the Venturi nozzle in the second group of comparison pipelines is 16mm-17mm;

[0021] The third group of comparison pipelines is provided with 2 branches, and the throat diameter of the Venturi nozzle in the third group of comparison pipelines is 22mm-23mm;

[0022] The fourth group of comparison pipelines is provided with 21 branches, and the throat diameter of the Venturi nozzle in the fourth group of comparison pipelines is 32mm-33mm.

[0023] Further, the air inlet system is provided with a main pipeline adjusting valve group and a bypass adjusting valve group, the main pipeline adjusting valve group is communicated with the calibration system

[0024] A calibration method of a flow measurement calibration device, comprising the following steps:

[0025] S1: high-pressure gas flow is delivered to the air inlet system, the gas supply flow is controlled by the main pipeline adjusting valve group, and the excess flow gas is discharged by the bypass adjusting valve group;

[0026] S2: The gas supplied in the air intake system enters the pressure stabilizing tank, and the gas is rectified and buffered in the pressure stabilizing tank to provide a pressure stable and uniform flow field for the critical flow venturi nozzle system;

[0027] S3: The stable gas enters the calibration system, and a high-precision critical flow venturi nozzle is used for transmission calibration standard of calibration test, and a ball valve on the corresponding group calibration pipeline is opened according to the test requirement;

[0028] S4: The gas after calibration enters the comparison system, and the gas is first introduced into the stagnation container to make the gas in a relative stagnation state, the corresponding comparison pipeline is opened according to the test requirement, and the gas enters the corresponding comparison pipeline for test, and the data is compared with the data of the calibration system;

[0029] S5: The gas enters the backflow pipe through the comparison pipeline, and the backflow pipe rectifies the output gas in the plurality of comparison pipelines

[0030] S6: According to the test requirement, the gas in the backflow pipe is introduced into the first flow pipe calibration system and the second flow pipe calibration system to calibrate the horn mouth type flow pipe and the classical venturi pipe form flow meter respectively.

[0031] Compared with the prior art, the present application has the following advantages:

[0032] Firstly, the comparison system is arranged in the present application, the calibration system is calibrated through the comparison system, the test device is verified and adjusted through the comparison with the standard equipment with known accuracy, the output difference of the test device and the standard equipment under the same flow condition is measured by comparing the test device with the standard equipment, the comparison system records and analyzes the difference, and the calibration is adjusted according to the accuracy of the standard equipment, so that the test device reaches the predetermined accuracy requirement.

[0033] Secondly, the calibration pipeline is divided into three groups in the present application, 11 calibration pipelines are arranged in the first group calibration pipeline and the second group calibration pipeline respectively, 22 calibration pipelines are arranged in the third group calibration pipeline, the throat diameter of the venturi nozzle in the first group calibration pipeline is 7mm-9mm, the throat diameter of the venturi nozzle in the second group calibration pipeline is 7mm-9mm, and the throat diameter of the venturi nozzle in the third group calibration pipeline is 22mm-24mm. As a high-precision calibration system, the maximum flow of the second group calibration pipeline and the third group calibration pipeline can reach 6.3kg / s, and the second group calibration pipeline and the third group calibration pipeline can be moved to other test devices or required occasions for calibration of other flow meters. According to the actual use of the test device, one group can be arranged for frequent use, and the other group can be arranged for infrequent use. Another function of the two groups is to test the frequently used group with the infrequently used group. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 Structure block of the present scheme Figure 1 ;

[0035] Figure 2 Structure block of the present scheme Figure 2 ;

[0036] Figure 3 Structure diagram of the calibration pipeline

[0037] Figure 4 Structure diagram of the comparison pipeline DETAILED DESCRIPTION

[0038] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate the present application and, together with the description, further serve to explain the principles of the application and enable a person skilled in the relevant art(s) to make and use the application. Figures 1-4

[0039] A flow measurement calibration device, comprising

[0040] An air intake system: introducing high-pressure gas and adjusting the flow of the input high-pressure gas;

[0041] A calibration system: testing and calibrating the input gas using a critical flow Venturi nozzle; it realizes accurate measurement and calibration of the flow by using a critical flow Venturi nozzle as a flow sensor, in combination with a comparison system and a calibration system;

[0042] A comparison system: calibrating the calibration system, verifying and adjusting the flow measurement equipment in the tester by comparing with a standard equipment with known accuracy, measuring the output difference of the flow measurement equipment in the tester and the standard equipment under the same flow condition by comparing them. The comparison system will record and analyze these differences, and make calibration adjustment according to the accuracy of the standard equipment, so that the flow measurement equipment in the tester can meet the predetermined accuracy requirements.

[0043] A first flow tube calibration system: for the calibration of the horn mouth type flow tube;

[0044] A second flow tube calibration system: for the calibration of the flow meter in the form of a classic Venturi tube;

[0045] The air intake system, calibration system and comparison system are connected in sequence, the first flow tube calibration system and the second flow tube calibration system are arranged in parallel at the output end of the comparison system, the calibration system comprises a pressure stabilizing tank, a gas collecting tank and a calibration pipeline, the air intake system is connected to the pressure stabilizing tank, a plurality of calibration pipelines are arranged, the input ends of the plurality of calibration pipelines are connected to the pressure stabilizing tank, the output ends of the plurality of calibration pipelines are connected to the gas collecting tank, and the calibration pipeline is sequentially provided with a ball valve, a measurement assembly, a Venturi nozzle and a ball valve from the input end to the output end.

[0046] ​The intake system introduces high-pressure gas with stable flow pressure into the calibration system for calibration. The calibrated gas enters the comparison system for calibration. The comparison system calibrates the calibration system. The critical flow Venturi nozzle is a special nozzle structure. When the fluid passes through the nozzle, the flow rate reaches the critical speed. At this time, the pressure and speed of the fluid meet certain relationships. By measuring the pressure and temperature of the fluid, the mass flow rate of the fluid can be calculated. Then the gas enters the first flow tube calibration system and / or the first flow tube calibration system for calibration. The bell mouth type flow tube and the classic Venturi tube are two forms of flow meters, which need to be calibrated by the critical Venturi nozzle system to ensure their accuracy. The calibration process involves multiple steps and components, and requires uncertainty analysis.

[0047] The tester uses a continuous gas source to deliver compressed air. The gas source is provided by an air compressor. The maximum flow rate is calculated as 104 kg / s. The pressure is 5.5 MPa. The temperature is about 313-353 K. The gas source delivery pipeline is laid to the vicinity outside the tester plant house. The connection is made by the tester. The pipeline is laid into the tester plant house.

[0048] A total air inlet valve is installed on the air inlet system to control the on-off of the pipeline. A main pipeline regulating valve group and a bypass regulating valve group are arranged after the valve to accurately control the air flow. When the flow tube is calibrated, the main pipeline regulating valve group is opened to make the air flow at a controlled speed. The pipeline after the bypass regulating valve group is discharged into the silencer tower.

[0049] Downstream of the air inlet system, a pressure stabilizing tank and a gas collecting tank are arranged to ensure that the flow field quality is close to the measurement standard. A plurality of calibration pipelines are connected after the pressure stabilizing tank. A Venturi nozzle is installed on each calibration pipeline. The Venturi nozzle is used as a high-precision measurement mass flow transmission standard to calibrate the flow tube.

[0050] A gas collecting tank is arranged after the calibration system to collect gas. A stagnation container is connected after the gas collecting tank to install a plurality of Venturi nozzles of the comparison system in a large space.

[0051] A backflow pipe is also arranged after the comparison system. The backflow pipe is connected to two parallel calibration pipes of the bell mouth type flow tube calibration system and the classic Venturi tube calibration system. Finally, the exhaust tower is discharged to the atmosphere.

[0052] After the test, the flow coefficient of the air inlet channel is determined by using the calibration equation, and the uncertainty analysis of the calibration test is carried out. In addition, according to the flow measurement calibration object being the bell mouth type flow tube or the classic Venturi tube, the valve opening and closing control after the comparison system can be used to select different pipelines for calibration.

[0053] The test data is recorded throughout the process, and various parameter signals collected during the test are transmitted to the acquisition computer through the pressure acquisition system and temperature acquisition system, and are displayed, processed, analyzed and stored.

[0054] Preferably, the plurality of calibration pipelines are divided into three groups, 11 calibration pipelines are arranged in the first group and the second group respectively, and 22 calibration pipelines are arranged in the third group. The throat diameter of the Venturi nozzle in the first group of calibration pipelines is 7mm-9mm; the throat diameter of the Venturi nozzle in the second group of calibration pipelines is 7mm-9mm; and the throat diameter of the Venturi nozzle in the third group of calibration pipelines is 22mm-24mm. As a high-precision calibration system, the maximum flow rate of the second group of calibration pipelines and the third group of calibration pipelines can reach 6.3kg / s, and they can be moved as a whole to other testers or required places to calibrate other flowmeters. According to the actual use of the tester, one of the two groups can be arranged for frequent use, and the other group can be arranged for infrequent use. Another function of arranging two groups is to use the infrequently used group to test the frequently used group.

[0055] Optionally, the measurement assembly includes a temperature measuring instrument and a pressure measuring instrument, two temperature measuring instruments are arranged at both ends of the Venturi nozzle, the temperature measuring instrument has a measurement range of (0-100)℃ and an accuracy of ±0.1℃, and the accuracy of the pressure measuring instrument directly determines the measurement accuracy of the device. Therefore, in order to ensure the high accuracy of the system, a high-precision pressure measuring instrument with an accuracy of 0.025% is selected, and digital signal transmission is used to ensure reliable signal transmission.

[0056] In order to further reduce the measurement uncertainty of the device, two pressure measuring instruments with different ranges are installed at the upstream manifold of the nozzle, i.e., a pressure measuring instrument with a range of 5.5MPa and a pressure measuring instrument with a range of 2.5MPa. According to the different measurement pressures, the corresponding range pressure measuring instrument is selected. A differential pressure transmitter is installed at each critical flow Venturi nozzle to measure the pressure difference between the manifold and the nozzle. The stagnation pressure at the nozzle is measured by the absolute pressure at the manifold and the differential pressure transmitter at the nozzle, thereby achieving the purpose of reducing the measurement uncertainty.

[0057] Preferably, the comparison system includes a stagnation container, a backflow pipe and a comparison pipeline, the calibration system is connected to the stagnation container, the comparison pipeline is provided with a plurality of comparison pipelines, the input ends of the plurality of comparison pipelines are connected to the stagnation container, the output ends of the plurality of comparison pipelines are connected to the backflow pipe, and a Venturi nozzle, a pressure measuring instrument and a valve are sequentially arranged in each comparison pipeline from the input end to the output end.

[0058] All critical flow Venturi nozzles of the comparison system use a large space installation method, and an AA-level temperature measuring instrument (±0.1℃) with a measurement range of (0-100)℃ is installed in the stagnation container.

[0059] For the pressure and temperature transmitter installed in large space, due to the large space mode, the gas in the stagnation container is in a relative stagnation state, so as long as the static pressure at any position of the stagnation container tank wall is obtained as the stagnation pressure of the device, in order to further reduce the measurement uncertainty of the device, three pressure transmitters with different ranges are installed in the stagnation container, which are three range segments of absolute pressure transmitters with ranges of 5.5 MPa, 2.5 MPa and 0.5 MPa, according to the different measured pressures, the corresponding range pressure transmitters are selected.

[0060] As preferred, the several contrast pipelines are divided into four groups, the total number is 21, and the total flow is 81.491 kg / s (when the pressure is 2.53 MPa),

[0061] The first group of contrast pipelines is provided with 1 branch, and the throat diameter of the venturi nozzle in the first group of contrast pipelines is 11mm-12mm;

[0062] The second group of contrast pipelines is provided with 1 branch, and the throat diameter of the venturi nozzle in the second group of contrast pipelines is 16mm-17mm;

[0063] The third group of contrast pipelines is provided with 2 branches, and the throat diameter of the venturi nozzle in the third group of contrast pipelines is 22mm-23mm;

[0064] The fourth group of contrast pipelines is provided with 21 branches, and the throat diameter of the venturi nozzle in the fourth group of contrast pipelines is 32mm-33mm.

[0065] Preferably, the air inlet system is provided with a main pipeline adjusting valve group and a bypass adjusting valve group, and the main pipeline adjusting valve group is in communication with the calibration system.

[0066] A calibration method of a flow measurement calibration device, characterized in that it comprises the following steps:

[0067] S1: high-pressure gas flow is delivered to the air inlet system, the gas flow is controlled by the main pipeline adjusting valve group, and the excess flow gas is discharged by the bypass adjusting valve group;

[0068] S2: the gas supplied in the air inlet system enters the pressure stabilizing tank, the gas is rectified and buffered in the pressure stabilizing tank to provide a pressure stable and uniform flow field for the critical flow venturi nozzle system;

[0069] S3: the stable gas enters the calibration system, and the high-precision critical flow venturi nozzle is used for transmission calibration standard of calibration test, and the ball valve on the corresponding group calibration pipeline is opened according to the test requirement;

[0070] S4: The calibrated gas enters the comparison system, the gas first enters the stagnation container to make the gas in a relative stagnation state, according to the test requirements, the corresponding valve is opened to open the corresponding comparison pipeline, the gas enters the corresponding comparison pipeline to test, and the measured data is compared with the data of the calibration system;

[0071] S5: The gas enters the backflow pipe through the comparison pipeline, and the backflow pipe rectifies the gas output from the plurality of comparison pipelines

[0072] S6: According to the test requirements, the gas in the backflow pipe is guided into the first flow pipe calibration system and the second flow pipe calibration system to calibrate the horn mouth type flow pipe and the classic venturi type flow meter respectively.

[0073] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the features defined as "first" and "second" can be explicitly or implicitly included one or more features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0074] In the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0075] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "illustrative embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0076] While embodiments of the application have been shown and described, it is to be understood that the application is not limited to the details of the embodiments described, since the scope of the application will be defined with respect to the claims and their equivalents.

Claims

1. A flow measurement calibration device, characterized in that, include: Intake system: Introduces high-pressure gas and regulates the flow rate of the input high-pressure gas; Calibration system: The input gas is tested and calibrated using a critical flow Venturi nozzle; Comparison system: calibrates the calibration system; First flow tube calibration system: used for calibrating bell-shaped flow tubes; Second flow tube calibration system: used to calibrate flow meters of the classic Venturi tube type; The air intake system, calibration system, and comparison system are connected in sequence. The first flow tube calibration system and the second flow tube calibration system are connected in parallel at the output end of the comparison system. The calibration system includes a pressure stabilizing tank, a gas collecting tank, and calibration pipelines. The air intake system is connected to the pressure stabilizing tank. Several calibration pipelines are provided. The input ends of the several calibration pipelines are connected to the pressure stabilizing tank, and the output ends of the several calibration pipelines are connected to the gas collecting tank. The calibration pipelines are provided with a ball valve, a measuring component, a venturi nozzle, and a ball valve in sequence from the input end to the output end. The calibration lines are divided into three groups. The first and second groups each have 11 calibration lines, and the third group has 22 calibration lines. The measuring components include a temperature measuring instrument and a pressure measuring instrument.

2. The flow measurement calibration device according to claim 1, characterized in that, The Venturi nozzle throat diameter in the first set of calibration lines is 7mm-9mm; the Venturi nozzle throat diameter in the second set of calibration lines is 7mm-9mm; and the Venturi nozzle throat diameter in the third set of calibration lines is 22mm-24mm.

3. The flow measurement calibration device according to claim 1, characterized in that, Two temperature measuring instruments are provided, and the two temperature measuring instruments are respectively set at both ends of the Venturi nozzle.

4. The flow measurement calibration device according to claim 1, characterized in that, The comparison system includes a stagnation container, a backflow tube, and a comparison pipeline. The calibration system is connected to the stagnation container. Several comparison pipelines are provided, with the input ends of the comparison pipelines connected to the stagnation container and the output ends of the comparison pipelines connected to the backflow tube.

5. A flow measurement calibration device according to claim 4, characterized in that, Each comparison line is equipped with a venturi nozzle, a pressure gauge, and a valve sequentially from the input to the output.

6. The flow measurement calibration device according to claim 5, characterized in that, Several comparison pipelines are divided into four groups. The first set of comparison pipelines is set with one tube, and the throat diameter of the Chinese Quli nozzle in the first set of comparison pipelines is 11mm-12mm; The second set of comparison pipelines is set up with one tube, and the throat diameter of the Chinese nozzle in the second set of comparison pipelines is 16mm-17mm. The third set of comparison pipelines consists of 2 lines, and the throat diameter of the Chinese-made Quli nozzle in the third set of comparison pipelines is 22mm-23mm. The fourth set of comparison pipelines consisted of 21 nozzles, and the throat diameter of the Chinese-made Churi nozzles in the fourth set of comparison pipelines was 32mm-33mm.

7. The flow measurement calibration device according to claim 1, characterized in that, The intake system is equipped with a main pipeline regulating valve group and a bypass regulating valve group, and the main pipeline regulating valve group is connected to the calibration system.

8. A calibration method based on the calibration apparatus according to any one of claims 1-7, characterized in that, Includes the following steps: S1: High-pressure gas flow is delivered to the intake system, and the gas supply flow is controlled by the main pipeline regulating valve group. Excess gas flow is discharged through the bypass regulating valve group. S2: The gas supplied by the intake system enters the pressure stabilizing tank, where it is rectified and buffered to provide a stable and uniform flow field for the critical flow Venturi nozzle system. S3: Stable gas enters the calibration system and is transmitted through a high-precision critical flow venturi nozzle to the calibration test standard. The ball valve on the corresponding group calibration pipeline is opened according to the test requirements. S4: After calibration, the gas enters the comparison system. The gas first enters the stagnation container to put the gas in a relatively stagnant state. According to the test requirements, the corresponding valve is opened to open the corresponding comparison pipeline. The gas enters the corresponding comparison pipeline for testing. The measured data is compared with the data of the calibration system. S5: Gas enters the backflow tube through the comparison tube, and the backflow tube rectifies the gas output from multiple comparison tubes. S6: According to the test requirements, guide the gas in the backflow tube to the first flow tube calibration system and the second flow tube calibration system to calibrate the bell-shaped flow tube and the classic Venturi tube type flow meter respectively.

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