What are the methods of airtightness test for the tank leak detector?

The airtightness of the product must be paid attention to when making the insulation cup. If the tank leak detector is not used well, the quality of the product purchased later will not be good, so it is important to know the airtightness detection method. Here I will also introduce it to you, mainly from three aspects.
What are the methods of airtightness test for the tank leak detector?
1. Pressure setting test (pressure maintaining method)
After inflating the measured object, directly measure the pressure change inside the measured object with a pressure gauge, U-tube or pressure sensor, and then calculate the leakage of the measured object. Its advantage lies in the simple structure of the test system. However, when the test environment is messy (such as temperature effect), the accuracy is required to be high and the leakage is small, or to save time and improve efficiency, this test method requires the accuracy of the pressure gauge or pressure sensor to be properly high, which makes this test method costly and even difficult to complete.
2. Differential pressure comparison method
Fill the tested object with compressed air at a certain pressure and keep it at a certain time. After the pressure sensor detects the change of pressure, compare this change with the pressure value of the standard sample (without leakage) under the same working condition to determine whether the tested object has leakage. According to the change of pressure, the leak detector can quantitatively detect whether the air tightness of the tested object is qualified. This method has gradually been widely used because of its advantages such as good enforceability, easier to distinguish sealing, no damage to contaminated parts, and easy to complete automation of the test process.
3. Water immersion method or surface spraying and coating method (visual inspection method)
After inflating the object to be measured, the object to be measured will enter a certain liquid (water is common) or soapy water will be applied to the object to be measured. The operator will judge whether there is leakage of the object to be measured based on the visual inspection of bubbles or soap bubbles in the liquid. This method mainly depends on the judgment of operators. Its advantages are intuitive and relatively reliable, but it is difficult to quantitatively measure the specific leakage of the measured object. A test environment and the operator's own condition also have a great impact on the test results. Cleaning, drying and anti-rust treatment of the tested object after using this method will directly affect the test results.