Vacuum technology —Test methods for leak rates of vacuum system
1 Scope
This standard specifies the test principles, instruments and equipment, test conditions, test procedures, interruption handling of leak rate test, test records and test reports for testing the leak rates of vacuum systems using helium mass spectrometry and pressure boosting method.
This standard is applicable to the leak rate test of vacuum system (hereinafter referred to as the specimen).
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 3163 Vacuum technology—Terminology
GB/T 3864-2008 Industrial nitrogen
GB/T 4844-2011 Pure helium, high pure helium and ultra pure helium
GB/T 18193 Vacuum technology—Mass-spectrometer-type leak detector calibration
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 3163 and the following apply.
3.1
effective minimum detectable leak rate
minimum leak rate that the leak detector can detect under the specific working conditions of the leak detector and the leak detection system after the specimens are connected with the leak detection system
Note: The unit is Pa·m3/s.
3.2
accumulation leak test
After the specimen is evacuated, close the accumulation valve to isolate it from the pumping system. When a certain concentration of helium is applied to the outside of the specimen, if there is a leak in the specimen, the helium leaked from the leak in the specimen will be accumulated in the specimen within the specified accumulation time, so that the helium partial pressure in the specimen will increase with the accumulation time. At the end of the accumulation time, open the accumulation valve, detect helium partial pressure in the specimen with the helium mass spectrometer leak detector so as to calculate the total leak rate of the specimen.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Test principle
5 Instruments and equipment
6 Test conditions
7 Test procedures
8 Interrupt handling of leak rate test
9 Test record and report
Bibliography
