An ideal onevacuum systemOr a vacuum container should be free of any leaks or air leakage. However, it is impossible for any vacuum system or vacuum container to remain leak free. Especially under extremely low pressure, the impact of air leakage continues to intensify, and the vacuum degree cannot meet the predetermined process requirements, which is a quite common problem. For this purpose, detecting the leaking parts of the vacuum system or vacuum container, determining the blockage of the leaking holes, and eliminating the leaking phenomenon have become important tasks for vacuum technicians.The so-called gas leakage, also known as actual leakage, refers to a phenomenon in which gas flows from the side to the low-pressure side through holes or gaps in a vacuum system. The commonly used basic concepts in vacuum leak detection technology mainly include the following points.
① Virtual leakage is a physical phenomenon relative to real leakage. This is mostly a phenomenon caused by the release of gas, desorption, condensation of materials, or the outflow of gas from dead spaces in the system, which leads to an increase in pressure in the vacuum system or container. During vacuum leak detection operations, it is necessary to eliminate the influence of virtual leaks.
② Airtightness - It is a performance that characterizes the degree to which the walls of a vacuum system or container are impermeable to air.
③ Leakage hole - Leakage hole refers to the irregularly shaped, extremely small holes or gaps that exist in a vacuum chamber. Enter the vacuum system or container through small holes or gaps larger than this.
④ Leakage rate - Leakage rate refers to the rate of gas leakage. It refers to the amount of gas that flows into a vacuum system or container through a leak or gap per unit time.
⑤ The minimum detectable leak rate refers to the smallest possible leak rate that can be detected by a certain leak detection method or instrument.
⑥ Leak detection sensitivity, also known as effective sensitivity, refers to the smallest leak rate that a leak detection instrument can detect in its working state.
⑦ Reaction time, also known as response time, refers to the time required from the start of the leak detection method (such as spraying leak gas) to the point when the indicated value of the method or instrument rises to 63% of its maximum value
⑧ The elimination time refers to the time required from the cessation of the leak detection method (such as stopping the injection of leak testing gas) to the point when the indicated value of the method or instrument drops to 37% of the cessation value,
⑨ Leakage blockage phenomenon refers to the blockage of leakage caused by dust or liquid. These blockages often refer to a temporary phenomenon that occurs due to improper leak detection operations. It seems that there is no leakage during leak detection, but once it is exhausted, there will be leakage again.