The problem lies in the airflow pattern. A uniformly distributed airflow only exists in theory. Outside the system, there are no precise analytical tools. There are areas of strong wind, areas of reduced wind, interspersed with areas of disturbance.
Placing the flow source in different areas will yield different results. Therefore, if you only take one point and record the reading, that number may not necessarily represent the entire system.
Where should the probe be placed to accurately reflect the evenly distributed airflow?
At the air outlet or fan outlet, the airflow is often not completely stable. The center tends to be stronger, while the edges are noticeably weaker.
Keeping the probe in a fixed position easily leads to only "touching" a portion of the airflow. Instead, gently moving it across multiple points along the same cross-section will help identify areas with less fluctuation.
Once a stable point is found, hold it there to record the reading. This approach helps to get closer to a more evenly distributed airflow distribution.
Why are the results different even when the location is the same?
Even when properly positioned, readings can vary between measurements. This is where the device's performance becomes apparent.
Uneven rotation, dust accumulation, or slow response from the sensor can all lead to unstable readings. These discrepancies aren't immediately noticeable, but they make it difficult to obtain consistent data.
Many organizations choose EMIN airflow measurement devices to maintain stability between measurements, especially in applications requiring data comparison and verification.
How long until the data can be read and used?
The value displayed immediately upon inserting the probe into the gas stream is usually not the final value. The gas stream needs a short time to stabilize at the measurement point.
Holding the probe in place long enough will cause the readings to gradually decrease. This is the appropriate time to record the reading. If the operation is too quick, the result will only reflect the instantaneous state.
Is one measurement point representative enough for the entire airflow?
With small air vents, a single stable point is acceptable. However, with large ducts or areas requiring assessment of evenly distributed airflow, one measurement point is almost insufficient.
Airflow varies from location to location, resulting in different values at each point. Averaging from multiple points will yield a more accurate result and is easier to use in subsequent steps.
How can the measurement data be used immediately?
A number's value lies in its repeatability. If measurements are taken multiple times at the same location and the value remains within a stable range, it can be used for calculation purposes.
Conversely, if the data changes continuously, both the probe position and the equipment status need to be reviewed.
Experienced individuals often don't just look at the number, but observe how it changes at each location. It is this change that reveals which value truly represents the airflow.
