With the development of natural gas industry in China, turbine flow meters, Vortex flow meters and Ultrasonic flow meters have been applied nationwide in recent years. It changes the fact that orifice flow meters used to cover about 95 % market of natural gas measurement. Those different flow meters are used to adapt to various process installation conditions. Meanwhile three traceability chains have been established in southwest and northeast of China for 10 years. The test facilities, management, inter-lab comparison and service in-situ has been promoted greatly, even to international...
Now, most gas flowmeters are taken to the special verification station to test (verify or calibrate) by manufacture in the world. It's obvious that shortcoming and wasting.The ChenDu Verification Branch (in brief CVB) imported a set of mobile gas ultrasonic measurement system for nature gas which is much advancer of the world from the Instromet company in Holland. After the gas ultrasonic meters have been tested in CVB, the system's performance is proved that it work very well and also can meet the requirement the nation build the mobile work standard for flowmeters in the field. It...
There is a professional 3-ton electric balance for gas mass flow measurement in Chengdu Verification Branch for Natural Gas Flow of National Crude Oil Large Flow Rate Measurement Station. The weighting range of this balance is 0 kg to 110 kg, the minimum sensible mass is 1 g, and the shift of indication value is no more than 2 g ( P = 95 %). It has been proved stable and reliable during its 8-year usage. This article brieves the method of improving the original circuit control system by applying advanced electric technology. Using this method, the shift of indication value can been reduced...
Key comparisons in the field of flow measurement have some peculiarities with impact on data evaluation and performance assessment, in paticular on the caluclation of the key comparison reference value (KCRV). The normal KC approach which assumes that all measurements in all laboratories are made at prescribed nominal sampling points faces problems in practical implementation. Furthermore, it is normally assumed that values submitted by participants are independent of each other. It is well-known that this assumption may not hold in specific cases since some of the factors which influence...
An auto-bell prover was set up at SPRING Singapore for the calibration of gas flow meters in the flow range of 3 m³/h to 100 m³/h or 1 to 33 g/s (dry air). The gas flow rate of the bell prover was determined by a primary method based on pressure, temperature, time and displaced volume measurements. The evaluations of the measurement uncertainties were carried out at the Gas Flow Laboratory of SPRING Singapore. The relative expanded measurement uncertainty was estimated to be less than +/- 0.2 % of readings. The performance of the auto-bell prover was checked using two transfer standards that...
Dry piston provers are similar in nature to conventional mercury-sealed flow provers, with the exception that the viscosity of the gas forms the seal across a very small (< 10 µ) section. As a result, very small, portable provers can be produced. Calibrations can be performed with the accuracy, primacy and large dynamic range of the earier mercury-sealed provers, but far more rapidly. The transportable nature of these primary instruments also makes them very useful for the inexpensive, ongoing harmonization of laboratories. Our latest uncertainty analysis shows a combined expanded...
Though air speed measurements are daily routine in many industries, calibration is still a problem due to the lack of standard. Though the Center for Measurement Standards (CMS) has established a calibration facility since 1997, the block effects resulted from small wind tunnel section constrained the devices to be calibrated. In this paper, a facility comprises a redesigned wind tunnel and a LDV with expanded lens was tested of its performance to estimate its uncertainty of measurement. Firstly, the expanded LDV probe was readjusted of its beam crossings and calibrated of its fringe...
Air velocity is a quantity often used in specifications of industrial processes or buildings. In these applications, the velocity is generally below 1 m·s -1 , the air temperature can be different from ambient one and the air can flow in any direction whatever. Furthermore, to reach minimum uncertainty measurements, a minimum calibration uncertainty of the used anemometer is needed as well as a calibration as close as possible to measurements conditions. To answer these needs, CETIAT has built a new anemometers' calibration test rig. Its evaluation is presented in terms of stability,...
National Metrology Institute of Turkey, UME, has partially completed the new gas flow velocity and gas flow rate measurement systems. In this article UME primary and secondary gas flow measurements systems for air at atmospheric conditions will be explained briefly. In the new gas flow laboratories, velocity measurements and anemometer calibrations are realized with a 2D Laser Doppler Anemometer .Two dimensional velocity measurements up to 40 m/s can be done in two different tunnels that have dimensions 500 × 500 mm and 250 × 250 mm. The wind tunnel system is constructed parallel to a gas...
This paper explains the way in which the traceability of the Bernoulli laboratory in Westerbork is organised and shows the reproducibility that is determined from the measurement results involved.