Compressed air flow is an important parameter to express the performance of air compressors and is also an important data measured in industrial processes. With the widespread use of air compressors, accurate measurement of their flow rates is essential for product upgrades, control and monitoring of industrial production processes, and energy saving and emission reduction. Especially in the trade metering of compressed air, the accurate measurement of gas consumption is the most direct benefit for both merchants and users.
Plug-in flowmeter is popular because of its ease of installation, and is more used for compressed air metering, especially with the advantages of integrated installation with pressure, which effectively solves the problem of non-stop measurement of the outlet main pipe of the air compressor station. There are two common plug-in flow meters, thermal flow meters and differential pressure flow meters. Because it is not possible to accurately meter compressed air containing impurities or moisture, thermal flow meters are not used much in the industry.
Differential pressure flowmeter is currently used in the compressed air industry more commonly used flowmeter. However, in the process of use, we found that the depth and angle of the insertion of the differential pressure flowmeter into the pipeline deviated, and the results measured by it were also different. However, to what extent does this deviation ultimately affect the measurement results? There has been a lack of a quantifiable study and data that can be referenced. Next, we chose to pass a set of comparison experiments, hoping to provide you with some basic references.
Differential pressure flowmeter installation site
1. The influence of the depth deviation of the differential pressure flowmeter into the pipeline on the measurement result
Taking the commonly used DN50, DN80, and DN100 pipelines as an example, a standard table is installed on the pipeline, and at the same time, within the range of repeatable conditions, four tables are installed in a way that deviates from the centerline by 5mm and 10mm respectively (the installation method is shown in Figure 1), and the data differences of each table are recorded.
Taking the DN80 pipeline running for 12h/day at a pressure of 7kg as an example, the standard table shows that the gas consumption is 17356m³/day. When the insertion depth deviates from the center line by 5mm, the table shows 16887.4m³/day, which deviates from the standard gas consumption by 2.7%. When the insertion depth is deviated by 10 mm, the table is 15828.7 m³/day, which is 8.8% different from the standard gas consumption. The specifics are shown in Table 1.
2. The influence of the angular deviation of the differential pressure flowmeter into the pipeline on the measurement result
Under the same conditions as above, the angle at which the differential pressure flowmeter is inserted into the pipe deviates from the central current plane by 5° and 10° respectively to observe the difference in the data of each table (the installation method is shown in Figure 2).
Taking the DN80 pipeline running for 12h/day at a pressure of 7kg as an example, the standard table shows that the gas consumption is 17356m³/day. When the insertion angle is offset by 5°, the table shows 16453.5m³/day, which is 5.2% different from the standard gas consumption. When the insertion depth is deviated by 10°, the table shows 15828.7 m³/day, which is 8.8% different from the standard gas consumption. The specific situation is shown in Table 2.
The above comparative experimental results show that the depth and angle deviation of the differential pressure flowmeter inserted into the pipeline can have a greater impact on the measurement results. During the installation and use of the differential pressure flowmeter, the fixed flowmeter cannot be continuously effective by clamp nuts alone. Therefore, in actual use, complex working conditions and human factor interference are very easy to "shake" the position of the differential pressure flowmeter, resulting in inaccurate measurement results. An "undetected collision" can affect measurement results for a long time. There is no good solution to this situation.