CNG加气站常规站与子站的经济性比较

介绍了CNG加气站常规站、子母站的工艺流程,并通过计算分析了常规站与子站的工作过程;同时从运营角度,对于在城市加气站工程设计中常出现的常规站、子站进行了经济性比较,为CNG加气站的建设提出了合理的建议。     

Development and validation of a dynamic primary standard for unsteady liquid flow calibration

LNE-CETIAT liquid flow laboratory is the French Designated Institute for liquid water flow rate from 1 g h⁻¹ to 50 t h⁻¹. Historically, its primary standards are based on the flying start and stop gravimetric method. The best relative expanded uncertainty for liquid mass flow rate is 0.05% (k = 2). In the scope of the Joint Research Project Metrowamet and its mission to maintain and develop the French standards for liquid flow, LNE-CETIAT has developed and validated a dynamic primary standard for unsteady liquid flow calibration. This paper will first present the developped system, which is composed of a dynamic flow generator and a dedicated measuring system together with its own software for data acquisition and processing. The validation, realized by intra and inter-laboratory comparisons for static and dynamic flows, is presented in the third chapter. Finally, the validation of the measurement and calibration capabilities, based on internal tests and inter-laboratory comparisons are presented.     

Investigations on pressure dependence of Coriolis Mass Flow Meters used at Hydrogen Refueling Stations

In the framework of the ongoing EMPIR JRP 16ENG01 “Metrology for Hydrogen Vehicles” a main task is to investigate the influence of pressure on the measurement accuracy of Coriolis Mass Flow Meters (CFM) used at Hydrogen Refueling Stations (HRS). At a HRS hydrogen is transferred at very high and changing pressures with simultaneously varying flow rates and temperatures. It is clearly very difficult for CFMs to achieve the current legal requirements with respect to mass flow measurement accuracy at these measurement conditions. As a result of the very dynamic filling process it was observed that the accuracy of mass flow measurement at different pressure ranges is not sufficient. At higher pressures it was found that particularly short refueling times cause significant measurement deviations. On this background it may be concluded that pressure has a great impact on the accuracy of mass flow measurement. To gain a deeper understanding of this matter RISE has built a unique high-pressure test facility. With the aid of this newly developed test rig it is possible to calibrate CFMs over a wide pressure and flow range with water or base oils as test medium. The test rig allows calibration measurements under the conditions prevailing at a 70 MPa HRS regarding mass flows (up to 3.6 kg min⁻¹) and pressures (up to 87.5 MPa).     

INRIM primary standard for microgas-flow measurements with reference to atmospheric pressure

Primary standard flowmeters are developed for the calibration of leak devices used in many applications in which is necessary to detect and quantify gas leakage from a material, a component or a system. At INRIM, a primary standard was designed and realized for the measurement of molar gas flow from 4 × 10⁻¹⁰ mol/s to 2 × 10⁻⁷ mol/s with reference to atmospheric pressure. It is based on the constant-pressure–variable-volume method and is able to work with any tracer gas.     

Development of low-pressure calibration system using a pressure balance

A new calibration system for low-pressure is now under development at NMIJ/AIST. The new system is designed to calibrate pressure transducers in the pressure range of less than 10 kPa in absolute mode. The pressure generation technique needs only a single pressure balance and the pressure in the bell-jar is used as a calibration pressure instead of the system pressure. In this paper, the outline of the calibration system and the measurement results are described.     

Application and uncertainty analysis of a balance weighing system used in natural gas primary standard up to 60 bar

A new 3-ton balance weighing system was designed and built up for a high level mass-time primary standard of natural gas up to 60 bar in CVB. The system is composed of a 3-ton electromagnetic balance, two tanks with thermal isolation, two platforms, two roller guide rails and two big weights which are used for special test. To achieve a lower uncertainty and the security application in natural gas measurement, several special methods were used in the system. Firstly, the tanks and platforms can be moved together steadily on the roller guide rail to be connected with pipeline system or to be weighted by the balance which also reduces the pipeline length between tanks and pipeline system. Secondly, the substitute weighing method is used for high accurate weighing. Finally, the whole system is located in a thermal isolated room with temperature and humidity controlling. Technical details, performance tests, uncertainty analysis and the future improvement ideas of the balance system are presented in the paper. The uncertainty analysis shows that the mass measurement uncertainty of gas can achieve less than 1.0g and the maximum relative standard uncertainty of natural gas mass measurement would be no more than 0.022%.     

An icosahedral virus as a fluorescent calibration standard: a method for counting protein molecules in cells by fluorescence microscopy

The ability to replace genes coding for cellular proteins with DNA that codes for fluorescent protein‐tagged versions opens the way to counting the number of molecules of each protein component of macromolecular assemblies in vivo by measuring fluorescence microscopically. Converting fluorescence to absolute numbers of molecules requires a fluorescent standard whose molecular composition is known precisely. In this report, the construction, properties and mode of using a set of fluorescence calibration standards are described. The standards are based on an icosahedral virus engineered to contain exactly 240 copies of one of seven different fluorescent proteins. Two applications of the fluorescent standards to counting molecules in the human parasite Toxoplasma gondii are described. Methods for improving the preciseness of the measurements and minimizing potential inaccuracies are emphasized.     

Gas Oil Piston Prover,primary reference values for Gas-Volume

The paper describes the design, measurement results and uncertainty analyses of the hydraulic driven piston-prover system which has been in operation at VSL since 2008. The 12-meter long, 0.6 m bore piston-prover is used for the realization of Reference Values for Gas-Volume at pressures between 1 and 65 bar(a) at several gases. The principle is based on the displacement of a piston acting as a Gas–Oil separator. The standard has a flow-rate range from 5 to 230 m³/h. The system is designed to calibrate reference meters. The Calibration and Measurement Capability (CMC) of the system is proven to be smaller than 0.1% (k=2). The paper also explains the coherence between the Gas–Oil piston-prover and other traceability generators and ‘flow rate bootstrapper systems’.     

A new automatic reference and switching unit for calibration of high value resistors in the range 100 kΩ to 10 TΩ

We describe a Reference and Switching Unit (RSU), that, with a digital multimeter (DMM) and a dc voltage calibrator, constitutes a system for calibration of standard resistors in the range 100 kΩ–10 TΩ at measurement voltages up to 1000 V. This system represents an implementation of a DMM-based system already developed at IEN. We report the characteristics of the DMM-based system, the metrological and electronic features of the RSU, the uncertainty levels that can be achieved with the DMM-based and whit the RSU-based systems. Finally, we show the obtained results in order to check the compatibility of the two systems in the calibration of standard resistors in the range 1 GΩ–1 TΩ. The 2σ best measurement capabilities of the RSU-based system span from 6.3×10⁻⁶ for the calibration of a 100 kΩ standard resistor at 10 V, to 1.2×10⁻³ for the calibration of 10 TΩ standard resistor at 1000 V.     

遥测自动气象站及人工EN风数据的远距离传输

介绍一种遥测自动气象站及人工EN风超远距离数据传输的方法,利用设备提供的标准RS232C端口输出数据,并输入到数字光端机,实现光纤传输通讯,最终将地面气象观测数据送入测报计算机。这种通讯方法已在台站得到实际应用。     

热连轧液压泵站控制系统设计与应用

根据热连轧精轧机组HAGC(液压自动厚度控制系统)液压泵站控制系统连续工作时间长、可靠性要求高、信号复杂的特点,以ABB公司AC800M型PLC为基础,对液压泵站的硬件构成、工作过程和程序结构进行设计.该液压泵站控制系统控制精度高、可靠性强,完全满足连轧机液压泵站控制要求,已经成功通过模拟调试,并将应用于生产实际.     

Development of a transfer standard with sonic Venturi nozzles for small mass flow rates of gases

We have developed a transfer standard system with sonic Venturi nozzles for small mass flow rates of gases. The system is composed of a newly developed automatic pressure controller, two pressure sensors and one temperature sensor to measure the flow conditions in the upstream and downstream sides of a nozzle. The whole system is packed in a portable aluminum trunk. The data are sent to a laptop computer, and the results are displayed on the screen and are written to files. The system can calibrate a flow meter in the flow rate range from 10 mg/min to 100 g/min using ten different sonic Venturi nozzles with the expanded standard uncertainty (k=2) being less than 0.2% for nitrogen. Examples of mass flow controller calibrations are given.     

Analysis of high pressure tests on wet gas flow metering with a Venturi meter

This work deals with the flow metering of wet gas issued from high pressure natural reservoirs. Some recent results obtained from tests performed on the CEESI facilities are presented. They are performed at 75 bar with 0.6 beta ratio Venturi meter installed in horizontal pipe configuration. Correction factors obtained are compared to predictions deduced from the flow modelling inside of the meter. These results are analysed in order to explain the agreements or disagreements obtained between the experiments and the flow modelling.     

Fabrication and calibration of a sub-miniature 5-hole probe with embedded pressure sensors for use in extremely confined and complex flow areas in turbomachinery research facilities

Multi-hole pressure probes are often employed in experimental facilities to measure the three dimensional flow field due to their ability to simultaneously provide the distributions of the static and total pressures as well as the three components of the velocity vectors. In cases where these probes are employed in turbomachinery research facilities it is essential for them to be accurate, respond to local parameter disturbances quickly and exhibit a high flow angle spatial sensitivity. Thus, the physical dimensions of the probe must be as small as possible. In addition the small size of the probe reduces the flow blockage and the corresponding local disturbances of the flow, especially when it approaches the solid boundaries of the blade channels. The present study refers to the fabrication and calibration of a sub-miniature in dimensions 5-hole probe, for use in complex internal flow areas arising in turbomachinery research. In order to reduce the need for a longer sampling time as the size of the probe gets smaller, the length of the stem that transfers the pressure from the tip of the probe to the sensor has to be minimized. This effect was compensated by embedding the pressure sensors right at the end of the probe׳s stem. This minimizes the air volume and thus the oscillations inside the flexible connecting tubes that usually connect each port of the probe to its corresponding pressure sensor. The fabrication methodology of the probe and data acquisition system is extensively described, as well as the non-nulling method employed for the calibration. Furthermore, application of the probe on a reference configuration geometry often used in turbomachinery research is illustrated in order to validate the effectiveness and novel characteristics of the probe. The result is a construction and calibration technique that allows the relevant laboratories to build on their own such instruments that may cost several thousand dollars (or euros) when bought from the open market.     

A new HPF specimen carrier adapter for the use of high‐pressure freezing with cryoscanning electron microscope: two applications: stearic acid organization in a hydroxypropyl methylcellulose matrix and mice myocardium

Cryogenic transmission electron microscopy of high‐pressure freezing (HPF) samples is a well‐established technique for the analysis of liquid containing specimens. This technique enables observation without removing water or other volatile components. The HPF technique is less used in scanning electron microscopy (SEM) due to the lack of a suitable HPF specimen carrier adapter. The traditional SEM cryotransfer system (PP3000T Quorum Laughton, East Sussex, UK; Alto Gatan, Pleasanton, CA, USA) usually uses nitrogen slush. Unfortunately, and unlike HPF, nitrogen slush produces water crystal artefacts. So, we propose a new HPF specimen carrier adapter for sample transfer from HPF system to cryogenic‐scanning electronic microscope (Cryo‐SEM). The new transfer system is validated using technical two applications, a stearic acid in hydroxypropyl methylcellulose solution and mice myocardium. Preservation of samples is suitable in both cases. Cryo‐SEM examination of HPF samples enables a good correlation between acid stearic liquid concentration and acid stearic occupation surface (only for homogeneous solution). For biological samples as myocardium, cytoplasmic structures of cardiomyocyte are easily recognized with adequate preservation of organelle contacts and inner cell organization. We expect this new HPF specimen carrier adapter would enable more SEM‐studies using HPF.     

Dynamic deformation of hot temperature degraded POM and PP using a modified SHPB with pulse shaper technique

The conventional split Hopkinson pressure bar (C-SHPB) technique with a special experimental apparatus is used to obtain a dynamic deformation material behavior under a high strain rate loading condition. An experimental modification is introduced to reduce the non-equilibrium on the dynamic material response during a short test period for two polymeric materials. The proposed method uses aluminum pressure bars to achieve a closer impedance match between the pressure bars and the specimen materials such as hot temperature degraded POM (Poly Oxy Methylene) and PP (Poly Propylene) to obtain more distinguishable experimental signals. In addition, a pulse shaper technique is used for increasing the rise time of the incident pulse to ensure the dynamic stress equilibrium and the homogeneous deformation in the specimen under dynamic compression loading condition. The details on the dynamic stress equilibrium and the duration of uniform strain rate during the dynamic deformation of the specimen are experimentally investigated. The effects of degradation at a few different hot temperatures on the maximum compressive stresses are also experimentally studied under varying impulsive loading conditions.