FORMAT
BOOKS
PACKAGES
EDITION
PUBLISHER
CONTENT TYPE
Act
Admin Code
Announcements
Bill
Book
CADD File
CAN
CEU
Charter
Checklist
City Code
Code
Commentary
Comprehensive Plan
Conference Paper
County Code
Course
DHS Documents
Document
Errata
Executive Regulation
Federal Guideline
Firm Content
Guideline
Handbook
Interpretation
Journal
Land Use and Development
Law
Legislative Rule
Local Amendment
Local Code
Local Document
Local Regulation
Local Standards
Manual
Model Code
Model Standard
Notice
Ordinance
Other
Paperback
PASS
Periodicals
PIN
Plan
Policy
Product
Product - Data Sheet
Program
Provisions
Requirements
Revisions
Rules & Regulations
Standards
State Amendment
State Code
State Manual
State Plan
State Standards
Statute
Study Guide
Supplement
Sustainability
Technical Bulletin
All
|
Description of BS ISO 21360-1:2020 2020This document specifies three 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 specified 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 at very small inlet pressures (under a high or ultra-high vacuum). It is based on measuring the ratio of pressures in a two-chamber test dome in which 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 are measured on a vacuum pump, but not specified in this document (e.g. measurement of power consumption), are defined in the specific pump standard.
About BSIBSI Group, also known as the British Standards Institution is the national standards body of the United Kingdom. BSI produces technical standards on a wide range of products and services and also supplies certification and standards-related services to businesses. |
GROUPS
|