Insertion depth for insertion type thermal gas mass flow meters

Project Overview

The insertion depth of the insertion thermal gas mass flow meter is related to many factors, mainly including the following points:

1. Pipe diameter: Pipe diameter is an important factor affecting the insertion depth. It is generally recommended that the insertion depth is between 1/2 and 2/3 of the pipe diameter to ensure that the measurement probe can capture the fastest flow area in the center of the pipe to obtain the most accurate measurement data. For large pipe diameters (≥300mm), the insertion depth of the sensor probe is generally 1/4 from the pipe wall to the pipe core; while for small pipe diameters (≤300mm), the insertion depth is usually 1/2.

2. Fluid flow state: Under laminar and turbulent flow conditions, the probe should be placed in a fully developed flow field and avoid measurements within the boundary layer to ensure that the average flow velocity representing the entire cross-section is captured. Especially in turbulent flow conditions, due to large changes in gas flow velocity, a longer insertion distance may be required to average the fluctuations in flow velocity.

3. Anti-clogging considerations: The probe should avoid places where solid impurities or liquids may accumulate at the bottom of the pipe to prevent clogging. At the same time, it is also necessary to prevent the installation position from being too shallow, causing fluid to flow around and affecting the measurement accuracy.

4. Gas properties: The density, viscosity, temperature and other properties of the gas will also affect the insertion distance. For example, high-viscosity gases may require longer insertion distances to ensure accurate measurement because the flow of such gases within the pipe may be more uneven.

5. Measurement accuracy requirements: The higher the requirements for measurement accuracy, the more stringent the insertion distance setting may be. To obtain more accurate measurements, it may be necessary to increase the insertion distance to reduce measurement error.

6. Flowmeter probe design: Flowmeter probes of different designs may have different requirements for insertion distance. Factors such as the size and shape of the probe and the sensitivity of the sensing element may affect the choice of insertion distance.

In summary, when selecting the insertion depth of an insertion thermal gas mass flow meter, the above-mentioned factors should be considered comprehensively to ensure the reliability and accuracy of the measurement results.