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Low-pressure critical flow Venturi nozzle calibration device

A technology of venturi nozzle and calibration device, applied in testing/calibration device, measuring device, liquid/fluid solid measurement, etc., can solve the problems of traceability and calibration of quantity value

Pending Publication Date: 2019-01-15
NAT INST OF METROLOGY CHINA +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to solve the problem that the sonic nozzle cannot be directly calibrated and traced to the source of the value under ultra-low pressure and large flow conditions.

Method used

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  • Low-pressure critical flow Venturi nozzle calibration device
  • Low-pressure critical flow Venturi nozzle calibration device

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Embodiment Construction

[0026] In order to facilitate the understanding of the present invention, the embodiments of the present invention will be described below in conjunction with the accompanying drawings. Those skilled in the art should understand that the following description is only for the convenience of explaining the present invention, not as a specific limitation on its scope.

[0027] Outflow coefficient C d As one of the important parameters of the outflow characteristics of the sonic nozzle, it is an important parameter that correlates the actual mass flow rate and the ideal mass flow rate of the sonic nozzle, and is also a key parameter to ensure the accuracy, reliability and uniformity of gas flow measurement. The schematic diagram of the test principle of the standard device is shown in figure 1 As shown, based on mass conservation, the mass flow through the standard sonic nozzle is equal to the mass flow through the tested sonic nozzle, and the stagnation temperature T of the stand...

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Abstract

The invention discloses a low-pressure critical flow Venturi nozzle calibration device. The low-pressure critical flow Venturi nozzle calibration device comprises an inlet pipe section, wherein one end of the inlet pipe section is directly connected to the atmosphere; the other end of the inlet pipe section extends to the inlet of a manifold; a plurality of channels are formed between the outlet of the manifold and the inlet of a reverse manifold; a pneumatic valve and a standard sonic nozzle are arranged in each channel; the standard sonic nozzles in the plurality of channels have different throat diameters; a plurality of pipelines are connected to a sonic nozzle to be measured; the outlet end of the sonic nozzle to be measured is a vacuum environment; a control part measures the temperatures and pressures of the standard sonic nozzles and the sonic nozzle to be measured; and the pneumatic valves in the plurality of channels are connected to the control part. A set of low-pressure sonic nozzle calibration device suitable for direct calibration and quantity traceability of the sonic nozzles under the conditions of ultra-low pressure and large flow rate is established, so that thetest condition of stagnation pressure being as low as 10kPa of a sonic nozzle under measurement can be realized.

Description

technical field [0001] The invention relates to a calibrating device, in particular to a calibrating device for a low-pressure critical flow Venturi nozzle. Background technique [0002] The critical flow Venturi nozzle (referred to as the sonic nozzle) is a differential pressure flowmeter that is gradually narrowed from the inlet to the throat and gradually expanded to the outlet, including a constriction section, a throat section and a diffusion section. Because of its simple structure, no moving parts, high accuracy, and good repeatability, the sonic nozzle is generally used as the transfer standard to transfer the value of other types of gas flowmeters at home and abroad. At the same time, the value of the sonic nozzle can be directly traced to the primary standard device of the national gas flow rate. Therefore, the sonic nozzle occupies an important position in the gas flow value traceability system, and is a key link to ensure accurate and reliable gas flow measureme...

Claims

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Application Information

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IPC IPC(8): G01F25/00
CPCG01F25/15
Inventor 李春辉苏金友袁世辉冯晓娟
Owner NAT INST OF METROLOGY CHINA
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