Norm

NEN-ISO 21360:2007 en

Vacuümtechniek - Standaardmethode voor het meten van een vacuümpompbeproeving - Algemene beschrijving

  • Deze norm is ingetrokken sinds 01-05-2012

124,99

Over deze norm

Status Ingetrokken
Aantal pagina's 27
Commissie Compressoren
Gepubliceerd op 01-06-2007
Taal Engels
This International Standard is a basic standard which defines three different methods for measuring the volume flow rate and one method each for measuring the base pressure, the compression ratio and the critical backing pressure of a vacuum pump. The first method for measuring the volume flow rate (the throughput method) is the basic concept, in which a steady gas flow is injected into the pump while the inlet pressure is measured. In practice, the measurement of gas throughput may be complicated or inexact. For this reason, two other methods are described which avoid the direct measurement of throughput. The second method for measuring the volume flow rate (the orifice method) is used when there is very small throughput occurring at very small inlet pressures (in the high and ultra-high vacuum). It is based on measuring the ratio of pressures in a two-chamber test dome where the two chambers are separated by a wall with a circular orifice. The third method for measuring the volume flow rate (the pump-down method) is well-suited for automated measurement. It is based on the evacuation of a large vessel. The volume flow rate is calculated from two pressures, before and after a pumping interval, and from the volume of the test dome. Different effects, such as leak and desorption rates, gas cooling by nearly isentropic expansion during the pumping interval and increasing flow resistance in the connection line between test dome and pump caused by molecular flow at low 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 vacuum pump, e.g. the measurement of the critical backing pressure is only necessary for vacuum pumps which need a 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

Details

ICS-code 23.160
Nederlandse titel Vacuümtechniek - Standaardmethode voor het meten van een vacuümpompbeproeving - Algemene beschrijving
Engelse titel Vacuum technology - Standard methods for measuring vacuum-pump performance - General description
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