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GB/T 40344.1-2021Vacuum technology - Standard methods for measuring vacuum-pump performance - Part 1: General description (English PDF)

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Issued by

State Administration for Market Regulation, China National Standardization Administration

Level / Type

National · Recommended

Issue date

August 20, 2021

Implementation date

March 1, 2022

Scope

GB/T 40344.1-2021 (Vacuum technology - Standard methods for measuring vacuum-pump performance - Part 1: General description) is available as an English-translated PDF.

GB/T 40344.1-2021 is the Chinese standard "Vacuum technology - Standard methods for measuring vacuum-pump performance - Part 1: General description".

Its scope clause reads: This part of GB/T 40344 specifies three volume flow rate measurement methods, and respectively specifies the measurement of base pressure and compression ratio of vacuum pumps, and the method of critical foreline pressure.

The first method of measuring volume flow rate (flow method) is a basic method. inject a stable flow of gas into the vacuum pump, and measure at the same time The inlet pressure of the pump.

In actual measurement, the measurement of gas flow may be complicated or inaccurate. For this reason, two other methods are prescribed to Avoid measuring flow directly.

The second method of measuring volume flow rate (small hole method) is suitable for very low inlet pressure (high vacuum or ultra-high vacuum) and very small flow rate Case.

The method is based on measuring the pressure ratio in the double test chamber of the test enclosure. The test cover is divided into two by a thin wall with a round hole Chamber.

The third method of measuring volume flow rate (pumping method) is based on the method of evacuating large vessels, which is very suitable for automated measurement. pass through The two pressure values before and after the pumping interval and the volume of the test cover are used to calculate the volume flow rate.

The measurement results and the final volume flow rate are affected by different Conditional influences, such as leakage rate and outgassing rate, gas cooling due to close to isentropic expansion during the pumping interval, and low-pressure molecular flow The flow resistance of the connecting pipeline between the test cover and the vacuum pump increases.

The choice of measurement method depends on the properties of the particular type of vacuum pump. For example, only a vacuum pump that needs to be equipped with a backing pump needs to be measured Critical foreline pressure.

All measurement parameters of vacuum pumps not specified in this section (such as measurement of power consumption) are specified in the standards of the corresponding pumps. To stipulate. Its clauses include terms and definitions.

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Document preview — GB/T 40344.1-2021

National Standard of the People's Republic of China

Classification: J 78

Issued by: State Administration for Market Regulation, China National Standardization Administration

Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Symbol
5 Test method
5.1 Measuring volume flow rate (pumping speed) by flow method
5.1.1 Overview
5.1.2 Test cover for flow method
5.1.3 Test device
5.1.4 Determination of volume flow rate
5.1.5 Measurement Step
5.1.6 Measurement uncertainty
5.1.7 Measurement evaluation
5.2 Measuring volume flow rate (pumping speed) by small hole method
5.2.1 Overview
5.2.2 Test cover for small hole method
5.2.3 Measuring device
5.2.4 Determination of volume flow rate
5.2.5 Small hole method measurement step
5.2.6 Adjustment of pressure measuring instruments
5.2.7 Measurement of volume flow rate
5.2.8 Measurement uncertainty
5.2.9 Measurement evaluation
5.3 Measurement of volume flow rate (pumping speed) by pumping method
5.3.1 Overview
5.3.2 Test cover for air extraction method
5.3.3 Snap Action Valve
5.3.4 Measuring device
5.3.5 Determination of volume flow rate
5.3.6 Measurement steps
5.3.7 Scope of application
5.3.8 Measurement and evaluation
5.3.9 Measurement uncertainty
5.4 Base pressure measurement
5.4.1 Operating conditions
5.4.2 Test steps under base pressure > 10-4Pa
5.4.3 Test steps under base pressure < 10-4Pa
5.4.4 Measurement evaluation
5.5 Compression ratio and critical foreline pressure measurement
5.5.1 Measuring device
5.5.2 Determination of compression ratio and critical foreline pressure
5.5.3 Measurement procedure
5.5.4 Measurement uncertainty
5.5.5 Measurement and evaluation
5.5.6 Special recommendations when measuring extremely high compression ratios
Appendix A (informative appendix) Mean free path of some important gases
Appendix B (Informative Appendix) Measurement Uncertainty

1 Scope

This part of GB/T 40344 specifies three volume flow rate measurement methods, and respectively specifies the measurement of base pressure and compression ratio of vacuum pumps.

And the method of critical foreline pressure.

The first method of measuring volume flow rate (flow method) is a basic method. inject a stable flow of gas into the vacuum pump, and measure at the same time

The inlet pressure of the pump. In actual measurement, the measurement of gas flow may be complicated or inaccurate. For this reason, two other methods are prescribed to

Avoid measuring flow directly.

The second method of measuring volume flow rate (small hole method) is suitable for very low inlet pressure (high vacuum or ultra-high vacuum) and very small flow rate

Case. The method is based on measuring the pressure ratio in the double test chamber of the test enclosure. The test cover is divided into two by a thin wall with a round hole

Chamber.

The third method of measuring volume flow rate (pumping method) is based on the method of evacuating large vessels, which is very suitable for automated measurement. pass through

The two pressure values before and after the pumping interval and the volume of the test cover are used to calculate the volume flow rate. The measurement results and the final volume flow rate are affected by different

Conditional influences, such as leakage rate and outgassing rate, gas cooling due to close to isentropic expansion during the pumping interval, and low-pressure molecular flow

The flow resistance of the connecting pipeline between the test cover and the vacuum pump increases.

The choice of measurement method depends on the properties of the particular type of vacuum pump. For example, only a vacuum pump that needs to be equipped with a backing pump needs to be measured

Critical foreline pressure. All measurement parameters of vacuum pumps not specified in this section (such as measurement of power consumption) are specified in the standards of the corresponding pumps.

To stipulate.

2 Normative references

The following documents are indispensable for the application of this document. For dated reference documents, only the dated version applies to this article

Pieces. For undated reference documents, the latest version (including all amendments) is applicable to this document.

ISO 3529-2 Vacuum technology terminology Part 2.Vacuum pump and related terms (Vacuumtechnology-Vocabulary-

Part 2.Vacuumpumpsandrelatedterms)

3 Terms and definitions

The terms and definitions defined in ISO 3529-2 and the following apply to this document.

The address of the terminology database maintained by ISO and IEC for standardization is as follows.

3.1 Volume flow rate

qV qV= dV dt

HG/T 6093 | GB 19815 | JB/T 8947 | GB/T 40344.4 | GB/T 40344.3 | GB/T 40333 | […]

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This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 44 pages — is available in the English PDF.

Referenced standards

Normative references

ISO 3529

Cited by

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