标准编号：ISO 21360:2007
中文名称：真空技术 测量真空泵性能的标准方法 一般说明
英文名称：Vacuum technology — Standard methods for measuring vacuum-pump performance — General description
发布日期：2007-06
标准范围
This International Standard is a basic standard which defines three different methods for measuring thevolume flow rate and one method each for measuring the base pressure, the compression ratio and the criticalbacking pressure of a vacuum pump.The first method for measuring the volume flow rate (the throughput method) is the basic concept, in which asteady gas flow is injected into the pump while the inlet pressure is measured. In practice, the measurementof gas throughput may be complicated or inexact. For this reason, two other methods are described whichavoid the direct measurement of throughput.The second method for measuring the volume flow rate (the orifice method) is used when there is very smallthroughput occurring at very small inlet pressures (in the high and ultra-high vacuum). It is based onmeasuring the ratio of pressures in a two-chamber test dome where the two chambers are separated by a wallwith a circular orifice.The third method for measuring the volume flow rate (the pump-down method) is well-suited for automatedmeasurement. It is based on the evacuation of a large vessel. The volume flow rate is calculated from twopressures, before and after a pumping interval, and from the volume of the test dome. Different effects, suchas leak and desorption rates, gas cooling by nearly isentropic expansion during the pumping interval andincreasing flow resistance in the connection line between test dome and pump caused by molecular flow atlow pressures, influence the results of the pressure measurement and the resulting volume flow rate.The choice of the required measurement methods depends on the properties of the specific kinds of vacuumpump, e.g. the measurement of the critical backing pressure is only necessary for vacuum pumps which needa backing pump. All data that is measured on a vacuum pump but not described in this International Standard (e.g. measurement of power consumption) is defined in the specific pump standard.
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