as everyone knows,Air tightness testing equipmentThe accuracy of detection is very critical. In all kinds of detection process, whether the detection is correct and efficient to carry out the detection work, we need to control
1. Affected by test pressure
The dependence of leakage rate on test pressure is different for different measurement conditions. Generally speaking, when the porosity (such as casting bubbles, cracks) is high, the test pressure is high
It has a great influence on the leakage rate, but has a little influence on the low porosity. In addition, with the increase of the test pressure, there will be temperature effects, such as the time required for stability
And so on. Therefore, it is suggested that leakage detection should be carried out within a certain pressure range for a specific workpiece, and then a better one meeting the test requirements should be selected
The low pressure is determined as the final test pressure. The selection of leak testing pressure of leak testing machine must fully consider the bearing capacity of each mechanism of the tested parts for the maximum test pressure.
2. Affected by the detection volume
In a specific leakage rate value, if the detection volume increases, the corresponding speed of pressure decrease will be lower, so the measurement time needs to be increased accordingly. stay
Under some specific conditions, if we do not try to reduce the measurement volume, we may not be able to achieve the required sensitivity.
3. Influence of stabilization time on detection
When the air is inflated, the compressed air will enter a closed container because of the pressure state, causing a series of thermodynamic dynamic changes, that is, when a certain volume of compressed air is compressed
When the air moves rapidly to a closed container, its pressure will decrease. If the measurement is carried out at this time, the change of pressure will be regarded as a pressure caused by leakage
The change will affect the accuracy of the measurement results. This & amp; ldquo; Impact effect & amp; rdquo; It is affected by inflation pressure, test volume and test piece material. When the inflation pressure or test volume increases,
The pressure reduction caused by this inflation becomes obvious. One way to solve this problem is to add a stable time between inflation and measurement to eliminate this effect.
The stabilization time should be determined according to the specific measurement object.
4. Influence of temperature on detection
For the gas in the closed container, when the temperature increases, the internal pressure increases. Therefore, the change of temperature will inevitably become the main factor affecting the change of pressure
There are many factors to be considered. It is generally estimated that the range of this effect is approximately 0.36% of the measured pressure value caused by every 1 ℃ change in temperature. Therefore, with the increase of test pressure
The effect of temperature will become obvious.
So, in the use of气密性检测设备In the process of testing, we should pay attention to the above four points, as well as some related details, so that our testing work will be more smooth