GB/T 40344.1-2021
Vacuum technology—Standard methods for measuring vacuum-pump performance—Part 1：General description
- Standard No.
- GB/T 40344.1-2021
- Language
- Chinese
- Release Date
- 2021
- Published By
- 国家市场监督管理总局、中国国家标准化管理委员会
- Lastest
- GB/T 40344.1-2021
- Scope
- This part of GB/T 40344 specifies three methods for measuring volumetric flow rate, and specifies methods for measuring vacuum pump base pressure, compression ratio and critical backing pressure respectively. The first method (flow method) for measuring volume flow rate is a basic method: injecting a steady flow of gas into the vacuum pump while measuring the inlet pressure of the pump. In actual measurement, the measurement of gas flow may be complicated or imprecise. For this purpose, two other methods are specified to avoid the direct measurement of flow. The second method of measuring volumetric flow rate (small hole method) is suitable for very low inlet pressure (high vacuum or ultra-high vacuum) and very small flow rate. The method is based on measuring the pressure ratio in the double test chamber of the test hood. The test hood is divided into two chambers by a thin wall with a round hole. The third method of measuring volumetric flow rate (pumping) is based on the evacuation of large vessels and is well suited for automated measurements. Calculate the volumetric flow rate from the two pressure values before and after the evacuation interval and the volume of the test hood. The measurement results and the resulting volume flow rate are influenced by various conditions, such as the leak rate and outgassing rate, the cooling of the gas during the pump-down interval due to the nearly isentropic expansion, the low-pressure molecular flow state that causes a gap between the test hood and the vacuum pump. The flow resistance of the connecting pipe increases. The choice of measurement method depends on the properties of the particular type of vacuum pump. For example, only vacuum pumps that require backing pumps need to measure critical backing pressure. All measurement parameters of vacuum pumps not specified in this section (such as the measurement of power consumption) are specified in the corresponding pump standards.
GB/T 40344.1-2021 Referenced Document
- ISO 3529-2 Vacuum technology — Vocabulary — Part 2: Vacuum pumps and related terms
GB/T 40344.1-2021 history
- 2021 GB/T 40344.1-2021 Vacuum technology—Standard methods for measuring vacuum-pump performance—Part 1：General description