JJG 577-2012 in English

1 Scope

This regulation is applicable to initial verification, subsequent verification and in-use inspection of diaphragm gas meters (hereinafter referred as gas meters).

2 Normative References

The following documents are referenced in this regulation:
JJF 1001-2011 General Terms in Metrology and Their Definitions
GB/T 6968-2011 Diaphragm Gas Meters
OIML Rl37-1&2: 2012 Gas Meters
0IML D11:2004 General Requirements for Electronic Measuring Instrument
EN 1359:1998+A1:2006 Diaphragm Gas Meters
For dated references, only the edition cited applies. For undated references, the latest edition of the normative document (including any amendments) applies.

3 Terms and Measuring Units

3.1 Terms
3.1.1 Maximum flow-rate qmax
The upper limit of flow-rate of gas meter complying with metering performance.
3.1.2 Minimum flow-rate qmin
The lower limit of flow-rate of gas meter complying with metering performance.
3.1.3 Transitional flow-rate qt
The flow-rate between the maximum and minimum flow-rate, dividing the flow-rate range of gas meter into "high area" and "low area". Both high area and low area are subject to corresponding maximum permissible error. qt equals to 0.1qmax.
3.1.4 Flow-rate range
The range limited by the maximum and minimum flow-rate complying with the metering performance of gas meter.
3.1.5 Maximum operating pressure pmax
The upper limit of gas meter operating pressure.
3.1.6 Pressure loss △p
The average pressure drop between air inlet and air outlet under maximum flow-rate.
3.1.7 Integrating value Q

Introduction I
1 Scope
2 Normative References
3 Terms and Measuring Units
3.1 Terms
3.2 Measuring Units
4 General
4.1 Principle and Structure
4.2 Purpose
5 Measuring Performance Requirements
6 General Technical Requirements
6.1 Nameplate and Marking
6.2 Appearance
6.3 Flow-rate Range
6.4 Indicating Device
6.5 Sealing
6.6 Pressure Loss
6.7 Ancillary Devices
6.8 Safety Performance
7 Control of Measuring Tools
7.1 Verification Conditions
7.2 Verification Items
7.3 Verification Methods
7.4 Verification Result Treatment
7.5 Verification Cycle
Appendix A Function Test for Ancillary Devices of Gas Meters
Appendix B Information and Format for Inside Page of Verification Certificate/Verification Result Notice