Parallel type double-station negative pressure method venturi nozzle gas flow standard device

Abstract

The utility model discloses a parallel type double-station negative pressure method venturi nozzle gas flow standard device, which relates to the field of gas flow standard detection devices and comprises a vacuum pump set, a surge tank, a collecting pipe, a venturi nozzle, a first stagnation container, a second stagnation container and a plurality of pipelines. The other end of the surge tank is communicated with a collecting pipe, the collecting pipe is communicated with a plurality of venturi nozzles, the plurality of venturi nozzles are respectively communicated with the first stagnation container and the second stagnation container, and the first stagnation container is communicated with the second stagnation container through a separating valve; and the first stagnation container and the second stagnation container are respectively communicated with a plurality of pipelines. According to the utility model, a single-station working mode and a double-station working mode can be independently selected and switched, so that the application range of the standard device can be widened, and the working efficiency can be effectively improved.

Description

Technical Field

[0001] The utility model relates to the field of gas flow standard detection devices, in particular to a parallel dual-station negative pressure Venturi nozzle gas flow standard device. Background Art

[0002] The working principle of a Venturi nozzle is based on Bernoulli's theorem and the continuity equation. It utilizes a special design inside the nozzle, including a converging section and a diverging section. When gas flows through the converging section of the nozzle, the flow velocity increases and the pressure decreases. According to Bernoulli's theorem, there is an inverse relationship between velocity and pressure. This increase in flow velocity leads to a decrease in pressure. In the diverging section of the nozzle, the flow velocity of the gas decreases and the pressure returns to a higher level. By measuring the pressure difference before and after the nozzle (i.e., the pressure difference between the converging section and the diverging section), the flow velocity of the gas can be deduced. According to the design parameters of the Venturi nozzle and the physical properties of the fluid, the flow velocity can be converted into flow rate.

[0003] As a metrological standard, the designed measurement ability of a Venturi nozzle gas flow standard device needs to be comprehensive, adaptable to inspected flowmeters of various diameters, and the measurement range needs to meet the usage requirements. According to its working principle, in the calibration test of traditional standard devices, different combinations of nozzles with different throat diameters are selected to obtain different flow standard values. The standard value reproduced in one test is single, and it can only calibrate a single flowmeter with a single diameter. From the perspective of working efficiency, it is difficult to meet the increasingly strong demand for quantity transfer and traceability in today's society.

[0004] Therefore, those skilled in the art urgently need to provide a parallel dual-station negative pressure Venturi nozzle gas flow standard device, which can independently select and switch between single-station and dual-station working modes, can not only improve the applicable range of the standard device, but also effectively improve the working efficiency. Summary of the Utility Model

[0005] The purpose of the utility model is to provide a parallel dual-station negative pressure Venturi nozzle gas flow standard device, which can independently select and switch between single-station or dual-station working modes, can not only improve the applicable range of the standard device, but also effectively improve the working efficiency.

[0006] To solve the above technical problems, the utility model adopts the following technical solutions:

[0007] The utility model relates to a parallel dual-station negative pressure French Venturi nozzle gas flow standard device, which comprises a vacuum pump group, a pressure stabilizing tank, a manifold pipe, Venturi nozzles, a first stagnation container, a second stagnation container and a plurality of pipelines. The vacuum pump group is communicated with one end of the pressure stabilizing tank, the other end of the pressure stabilizing tank is communicated with a manifold pipe, the manifold pipe is connected in parallel with a plurality of Venturi nozzles, the plurality of Venturi nozzles are respectively communicated with the first stagnation container and the second stagnation container, the first stagnation container and the second stagnation container are communicated through a separation valve, the first stagnation container and the second stagnation container are respectively communicated with a plurality of pipelines, and a flowmeter under test is communicated on the pipeline.

[0008] Preferably, a control valve is communicated between the manifold pipe and the Venturi nozzles, a control valve is communicated between the first stagnation container and the plurality of pipelines, a control valve is communicated between the second stagnation container and the plurality of pipelines, and a control valve is communicated between the vacuum pump group and the pressure stabilizing tank.

[0009] Preferably, the volume of the first stagnation container is larger than that of the second stagnation container.

[0010] Preferably, the diameter sizes of the plurality of pipelines communicated with the first stagnation container are larger than those of the plurality of pipelines communicated with the second stagnation container; the number of Venturi nozzles communicated with the first stagnation container is more than that of the Venturi nozzles communicated with the second stagnation container.

[0011] Preferably, temperature and humidity sensors and absolute pressure sensors are installed on the plurality of pipelines.

[0012] Preferably, temperature and humidity sensors and absolute pressure sensors are installed on both the first stagnation container and the second stagnation container, a differential pressure sensor is communicated between the first stagnation container and the manifold pipe, and another differential pressure sensor is communicated between the second stagnation container and the manifold pipe.

[0013] Compared with the prior art, the beneficial technical effects of the utility model are as follows:

[0014] For the parallel dual-station negative pressure French Venturi nozzle gas flow standard device of the utility model, when the separation valve is closed, two stations share a set of gas sources to form two sets of independent flow standard devices, and calibration tests can be carried out on two flowmeters under test simultaneously, which is the dual-station mode;

[0015] When the maximum flow rate standard value provided by the Venturi nozzle on the first stagnation container fails to meet the detection requirements, or when the maximum flow rate standard value provided by the Venturi nozzle on the second stagnation container fails to meet the detection requirements, the first stagnation container and the second stagnation container are connected by controlling the opening of the separation valve. At this time, the flow detection device is in the single-station mode, so that the working mode of single-station or double-station can be independently selected and switched, which can not only improve the applicable range of the standard device, but also effectively improve the working efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be further described below in conjunction with the accompanying drawings.

[0017] Figure 1 FIG. is a schematic perspective view of a parallel dual-station negative pressure Venturi nozzle gas flow rate standard device of the present invention;

[0018] Figure 2 FIG. is a top view of a parallel dual-station negative pressure Venturi nozzle gas flow rate standard device of the present invention.

[0019] Description of reference numerals: 1. Vacuum pump group; 2. Pressure stabilizing tank; 3. Confluence pipe; 4. DN25 pipeline; 5. Venturi nozzle; 6. First stagnation container; 7. DN300 pipeline; 8. DN250 pipeline; 9. DN200 pipeline; 10. DN150 pipeline; 11. Separation valve; 12. Second stagnation container; 13. DN100 pipeline; 14. DN80 pipeline; 15. DN50 pipeline. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0021] As Figure 1-2 shown, a parallel dual-station negative pressure Venturi nozzle gas flow rate standard device includes a vacuum pump group 1, a pressure stabilizing tank 2, a confluence pipe 3, a Venturi nozzle 5, a first stagnation container 6, a second stagnation container 12 and a plurality of pipelines. One end of the vacuum pump group 1 is connected to the pressure stabilizing tank 2, the other end of the pressure stabilizing tank 2 is connected to a confluence pipe 3, the confluence pipe 3 is connected in parallel with a plurality of Venturi nozzles 5, the plurality of Venturi nozzles 5 are respectively connected to the first stagnation container 6 and the second stagnation container 12, the first stagnation container 6 and the second stagnation container 12 are connected through a separation valve 11, the first stagnation container 6 and the second stagnation container 12 are respectively connected to a plurality of pipelines, and a flowmeter under test is connected to the pipeline.

[0022] A control valve is connected between the manifold 3 and the Venturi nozzle 5. A control valve is connected between the first stagnation container 6 and multiple pipelines. A control valve is connected between the second stagnation container 12 and multiple pipelines. A control valve is connected between the vacuum pump group 1 and the pressure stabilizing tank 2.

[0023] The volume of the first stagnation container 6 is larger than the volume of the second stagnation container 12.

[0024] The diameter sizes of the multiple pipelines connected to the first stagnation container 6 are larger than the diameter sizes of the multiple pipelines connected to the second stagnation container 12; the number of Venturi nozzles 5 connected to the first stagnation container 6 is more than the number of Venturi nozzles 5 connected to the second stagnation container 12.

[0025] Specifically, the vacuum pump group 1 is formed by connecting three vacuum pumps in parallel.

[0026] Specifically, the first stagnation container 6 is connected to a DN300 pipeline 7, a DN250 pipeline 8, a DN200 pipeline 9, and a DN150 pipeline 10; the second stagnation container 12 is connected to a DN100 pipeline 13, a DN80 pipeline 14, a DN50 pipeline 15, and a DN25 pipeline 4.

[0027] Specifically, considering aspects such as size specifications, flow rate ranges, and comprehensiveness, the Venturi nozzle 5 is designed in a combination form of 2 n Nm 3 / h, as shown in Table 1.

[0028] Specifically, the first stagnation container 6 is connected to sixteen Venturi nozzles 5, numbered from number one to number sixteen; the second stagnation container 12 is connected to ten Venturi nozzles 5, numbered from number seventeen to number twenty-six.

[0029] Table 1 Reference table for the designed flow rate of the Venturi nozzle

[0030]

[0031] Temperature and humidity sensors and absolute pressure sensors are installed on multiple pipelines.

[0032] Temperature and humidity sensors and absolute pressure sensors are installed on both the first stagnation container 6 and the second stagnation container 12. A differential pressure sensor is connected between the first stagnation container 6 and the manifold 3, and another differential pressure sensor is connected between the second stagnation container 12 and the manifold 3. The differential pressure sensor 19 is used to detect the pressure difference between the stagnation container and the manifold.

[0033] One of the embodiments is a single-station mode,

[0034] Install the flowmeter to be inspected in pipeline 7 with DN300, pipeline 8 with DN250, pipeline 9 with DN200, and pipeline 10 with DN150 according to its specifications. When the maximum flow standard value provided by the Venturi nozzle on the first stagnation container 6 fails to meet the detection requirements, control the opening of the separation valve 11 to connect the first stagnation container 6 with the second stagnation container 12. At this time, the flow device is in the single-station mode, which is the same as the use of the traditional Venturi nozzle gas flow standard device, and only calibration tests can be carried out on a single flowmeter to be inspected.

[0035] Or install the flowmeter to be inspected in pipeline 13 with DN100, pipeline 14 with DN80, pipeline 15 with DN50, and pipeline 4 with DN25 according to its specifications. When the maximum flow standard value provided by the Venturi nozzle on the second stagnation container 12 fails to meet the detection requirements, control the opening of the separation valve 11 to connect the first stagnation container 6 with the second stagnation container 12. At this time, the flow device is in the single-station mode, which is the same as the use of the traditional Venturi nozzle gas flow standard device, and only calibration tests can be carried out on a single flowmeter to be inspected. At this time, the relevant calculation formula is:

[0036] Q s =Q s(A) +Q s(B)

[0037]

[0038] Wherein in the formula: Q s ——The standard value of the flow device

[0039] Q s(A) ——The flow standard value reproduced by selecting a nozzle from nozzle station A

[0040] Q s(B) ——The flow standard value reproduced by selecting a nozzle from nozzle station B

[0041] Q1——The indication value of the flowmeter to be inspected

[0042] E——The relative error of the flowmeter to be inspected

[0043] The single-station mode is a supplementary function design of this device, which realizes the expansion of the flow upper limit of the two detection stations, and is mainly used for detecting some flowmeters to be inspected with wide ranges and relatively high upper limit values, effectively broadening the applicable range of the standard device.

[0044] Another embodiment is the double-station mode:

[0045] By controlling the closing of the separating valve 11, the first stagnation container 6 is separated from the second stagnation container 12. At this time, the detection station A is composed of sixteen Venturi nozzles 5, a control valve, the first stagnation container 6, a DN300 pipeline 7, a DN250 pipeline 8, a DN200 pipeline 9, and a DN150 pipeline 10. It shares the gas source composed of a vacuum pump group 1, a pressure stabilizing tank 2, and a manifold 3 with the detection station B composed of a Venturi nozzle 5, a control valve, the second stagnation container 12, a DN100 pipeline 13, a DN80 pipeline 14, a DN50 pipeline 15, and a DN25 pipeline 4, constituting two independent flow rate standard devices, which can simultaneously carry out calibration tests on the flow meters under inspection at the two stations. At this time:

[0046]

[0047]

[0048] In the formula: Q A —— The indication value of the flow meter under inspection at station A

[0049] Q B —— The indication value of the flow meter under inspection at station B

[0050] Q s(A) —— The flow rate standard value reproduced by the nozzle selected from nozzle station A

[0051] Q s(B) —— The flow rate standard value reproduced by the nozzle selected from nozzle station B

[0052] E A —— The relative error of the flow meter under inspection at station A

[0053] E B —— The relative error of the flow meter under inspection at station B

[0054] In the dual-station mode, one of the stations can also be selected separately to carry out the detection work. For the flow meters under inspection with small specifications, station B is independently used for detection, and the smaller stagnation container is conducive to stabilizing the flow rate more quickly.

[0055] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0056] The embodiments described above are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A parallel double-station negative pressure Venturi nozzle gas flow standard device, characterized by: The invention comprises a vacuum pump group (1), a pressure-stabilizing tank (2), a manifold (3), a venturi nozzle (5), a first stagnation container (6), a second stagnation container (12) and a plurality of pipelines. The vacuum pump group (1) is connected to one end of the pressure-stabilizing tank (2), the other end of the pressure-stabilizing tank (2) is connected to the manifold (3), the manifold (3) is connected to a plurality of venturi nozzles (5) in parallel, the plurality of venturi nozzles (5) are respectively connected to the first stagnation container (6) and the second stagnation container (12), the first stagnation container (6) and the second stagnation container (12) are connected via a separation valve (11), the first stagnation container (6) and the second stagnation container (12) are respectively connected to a plurality of pipelines, and the pipelines are connected to flow meters to be inspected.

2. A parallel double-station negative pressure Venturi nozzle gas flow standard device according to claim 1, characterized in that: A control valve is connected between the manifold (3) and the Venturi nozzle (5), a control valve is connected between the first stagnation container (6) and the plurality of pipelines, a control valve is connected between the second stagnation container (12) and the plurality of pipelines, and a control valve is connected between the vacuum pump group (1) and the pressure-stabilizing tank (2).

3. A parallel double-station negative pressure Venturi nozzle gas flow standard device according to claim 1, characterized in that: The volume of the first stagnation container (6) is greater than the volume of the second stagnation container (12).

4. A parallel double-station negative pressure Venturi nozzle gas flow standard device according to claim 3, characterized in that: The diameters of the multiple pipelines connected to the first stagnation container (6) are larger than the diameters of the multiple pipelines connected to the second stagnation container (12); the number of Venturi nozzles (5) connected to the first stagnation container (6) is greater than the number of Venturi nozzles (5) connected to the second stagnation container (12).

5. The parallel double-station negative pressure Venturi nozzle gas flow standard device according to claim 1, characterized in that: Temperature and humidity sensors and absolute pressure sensors are installed on the plurality of pipelines.

6. A parallel double-station negative pressure Venturi nozzle gas flow standard device according to claim 1, characterized in that: The first stagnation container (6) and the second stagnation container (12) are both installed with a temperature and humidity sensor and an absolute pressure sensor; a differential pressure sensor is connected between the first stagnation container (6) and the manifold (3); and another differential pressure sensor is connected between the second stagnation container (12) and the manifold (3).

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