GB/T 18604-2014 in English

《GB/T 18604-2014用气体超声流量计测量天然气流量》由TC355（全国石油天然气标准化技术委员会）归口，TC355SC10（全国石油天然气标准化技术委员会油气计量及分析方法分会）执行，主管部门为国家标准化管理委员会。
本标准规定了气体超声流量计的测量性能要求、流量计本体要求、安装和维护、现场验证测试要求,以及流量计算方法及测量不确定度估算。
本标准适用于插入式传播时间差法气体超声流量计(以下简称流量计),一般用于集输装置、输气管线、储存设施、配气系统和用户计量系统中的天然气流量测量。外夹式气体超声流量计的使用可参考本标准。

1 Scope

This standard specifies measuring performance requirements, meter body requirements, installation and maintenance, site verification testing requirement as well as flow calculation method and measurement uncertainty estimation of ultrasonic flow meters.

This standard is applicable to plug-in gas ultrasonic flow meter (transit-time difference method, hereinafter referred to as flow meter) and is generally used for measurement of natural gas flow in gathering and transportation device, gas transmission line, storage facility, gas distribution system and user metering system. The use of jacket-type gas ultrasonic flow meter may also refer to this standard.

2 Normative References

The following documents for the application of this document are essential. Any dated reference, only the edition cited applies. For the undated reference, the latest edition (including any amendments) applies.

GB 3836.1 Explosive Atmospheres - Part 1: Equipment - General Requirements
GB 3836.2 Explosive Atmospheres - Part 2: Equipment Protection by Flameproof Enclosures “d”
GB 3836.4 Explosive atmospheres - Part 4: Equipment protection by intrinsic safety
GB/T 4208 Degrees of Protection Provided by Enclosure (IP Code) ((IEC 60529)
GB/T 11062-1998 Natural Gas - Calculation of Calorific Values, Density, Relative Density and Wobbe Index from Composition
GB/T 13610 Analysis of Natural Gas by Gas Chromatography
GB/T 17747(All parts) Natural Gas - Calculation of Compression Factor
GB/T 21446-2008 Measurement of Natural Gas Flow by means of Standard Orifice Meter
SY/T 0599-2006 Metallic Material Requirements on Resistance to Sulfide Stress Cracking and Stress Corrosion Cracking for Natural Gas Surface Equipment
JJG 1030-2007 Ultrasonic Flowmeters
IS0 5167-1: 2003 Measurement of Fluid Flow by Means of Pressure Differential Devices Inserted in Circular Cross-section Conduits Running Full - Part 1: General Principles and Requirements)
AGA Report No.10 Speed of Sound in Natural Gas and Other Related Hydrocarbon Gases)

3 Quantities, Terms and Definitions

3.1 Quantities

See Table 1 for names and symbols of quantities and units in this standard.

Foreword i
1 Scope
2 Normative References
3 Quantities, Terms and Definitions
4 Measurement Principle
4.1 Basic Principle
4.2 Influencing Factors of Measuring Accuracy
5 Working Conditions
5.1 Natural Gas Quality
5.2 Pressure
5.3 Temperature
5.4 Flow Range and Flow Direction
5.5 Velocity Distribution
6 Measuring Performance Requirements
6.1 Requirements on Measuring Performance of Multi-path Gas Ultrasonic Flow Meter
6.2 Requirements on Measuring Performance of Single-path Gas Ultrasonic Flow Meter
6.3 Influence of Working Condition on Measuring Performance
7 Flow Meter Requirements
7.1 Composition and Basic Requirement
7.2 Meter Body
7.3 Ultrasonic Transducer
7.4 Electronic Part
7.5 Flow Rate Computer
8 Installation Requirement and Maintenance
8.1 Influence Factors against Installation
8.2 Pipe Arrangement
8.3 Maintenance
9 Requirements for Site Validation and Testing
9.1 Testing Content and Procedure
9.2 Testing Report
10 Flow Rate Calculation Method and Measurement Uncertainty Estimation
10.1 Flow Calculation in Standard Reference Conditions
10.2 Determination of Measured Flow in Standard Reference Conditions
10.3 Calculation of Flow in Working Conditions
10.4 Uncertainty estimation of flow measurement
Annex A (Informative) Basic Principle
Annex B (Normative) Flow Calibration of Metering Package
Annex C (Normative) End-of-manufacturing Testing Requirements
Annex D (Informative) Available Documents
Annex E (Informative) Generation of Acoustic Noise and Control Measures
Annex F (Informative) Performance Verification Test on Flow Meter and Flow Conditioner
Annex G (Informative) Monitoring and Guarantee of Site Measuring Performance of Flow Meter