The primary dynamic gravimetric system for gas mass flow measurement

High accuracy mass flow measurement is an enabling technology at the base of many industries. HORIBA STEC Co., Ltd. developed its own primary gas mass flow measurement system. We employed the dynamic gravimetric method in a vacuum chamber, and we use only mass and time information for mass flow rate calculation, with no correction for temperature, pressure and humidity. The system achieved 0.036% uncertainty as lowest of results with satisfactory performance of proficiency testing with NIST (National Institute of Standards and Technology). Then the laboratory has been granted ISO/IEC 17025 accreditation since 2017. This paper describes the system details and uncertainty analysis.     

Hydrogen refuelling station calibration with a traceable gravimetric standard

Of all the alternatives to hydrocarbon fuels, hydrogen offers the greatest long-term potential to radically reduce the many problems inherent in fuel used for transportation. Hydrogen vehicles have zero tailpipe emissions and are very efficient. If the hydrogen is made from renewable sources, such as nuclear power or fossil sources with carbon emissions captured and sequestered, hydrogen use on a global scale would produce almost zero greenhouse gas emissions and greatly reduce air pollutant emissions.The aim of this work is to realise a traceability chain for hydrogen flow metering in the range typical for fuelling applications in a wide pressure range, with pressures up to 875 bar (for Hydrogen Refuelling Station - HRS with Nominal Working Pressure of 700 bar) and temperature changes from −40 °C (pre-cooling) to 85 °C (maximum allowed vehicle tank temperature) in accordance with the worldwide accepted standard SAE J2601. Several HRS have been tested in Europe (France, Netherlands and Germany) and the results show a good repeatability for all tests. This demonstrates that the testing equipment works well in real conditions. Depending on the installation configuration, some systematic errors have been detected and explained. Errors observed for Configuration 1 stations can be explained by pressure differences at the beginning and end of fueling, in the piping between the Coriolis Flow Meter (CFM) and the dispenser: the longer the distance, the bigger the errors. For Configuration 2, where this distance is very short, the error is negligible.     

重力式自动装料衡器检定标准装置的测量不确定度评定

本文就重力式自动装料衡器依法监督管理中需建立的标准检定装置的测量不确定度问题做些表述与分析,介绍了该装置的法规要求、试验测量方法及数学模型,重点阐述了测量不确定度来源及评定。     

WQF-2004型动态微量气溶胶发生器的研制

研制了一种动态微量气溶胶发生器.介绍了该装置的基本原理、组成部分、气路系统、电路系统和性能测试结果.     

Water density formulations and their effect on gravimetric water meter calibration and measurement uncertainties

In the gravimetric calibration method of water meters, the volume of water that has passed through the equipment under test (EUT) is generally collected into a tank and the quantity (mass) determined by weighing. The mass of water collected is then converted into a volume. This conversion of mass into volume requires knowledge of the water density, which can be estimated, measured directly or determined by other means. The error of measurement of the EUT is determined by comparing the volume recorded by the EUT and the volume collected in the tank. The density of water is, therefore, one of the major causes of measurement uncertainty in laboratory calibration of water meters using the gravimetric method. Water meter calibration facilities commonly use density formulations proposed by the International Standards Organisation (ISO) and the Organisation for International Legal Metrology (OIML). In Australia, additional guidance in water density determination is provided by the National Measurement Institute (NMI). In this study, testing was undertaken using ten positive displacement water meters arranged in series in the test rig to evaluate some of the common water density formulations used in Australia. The effect of these different formulations on the water meter error measurement was determined, as well as the effect on the measurement uncertainties. The results shows that the use of these different density formulations evaluated do not significantly affect the water meter error of measurement or the uncertainty of measurement. There was no apparent correlation between the water meter error and the meter position in the test rig. It was also determined that if the water density was adjusted only for temperature effects, a maximum of 0.05 and 0.15% drift in meter error and measurement uncertainty respectively, can be expected.     

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.     

A capillary fluorescence standard for microfluorometry

Quartz glass capillaries of about 6 μm inside diameter were filled with fluorochrome solutions of accurately known concentrations and embedded as microscopical objects. The fluorescence intensity of a constant capillary volume has been found to be directly proportional to the amount of the excited fluorochrome in this volume within the fluorochrome concentration range 1:10³. The capillary volume can be determined accurately by microinterferometric measurement of the inside diameter. The capillary section irradiated by the exciting light may be considered as very small in comparison with the total length of the capillary tube. During and after irradiation the excited part of fluorochrome solution is continuously renewed by convectional flow and diffusion. Therefore photodecomposition does not affect the measured fluorescence intensity, and the standard value remains unchanged even after numerous measurements. Thus, these fluorescence standards may be used to make successive calibrations of a microfluorometer and to check the constancy and reproducibility of measuring conditions. In certain circumstances it also permits measured fluorescence intensity to be interpreted in terms of the amount of fluorochrome or fluorescent substance. The results achieved with the capillary fluorescence standard are compared with those obtained by means of conventional methods. In addition, some essential optical properties of the microfluorometer equipment required for the proper use of this standard are discussed.     

标准动态力源装置液压系统设计及其加载控制

在介绍１２ ＭＮ 标准动态力源装置的基础上,对所设计的液压系统及其加载控制方法作了详尽的说明,其中高压油封和和油封压力自动调节控制较有特色     

A convenient standard for low-field susceptibility calibration

Finely ground mixtures of magnetic iron oxide and glass provide a convenient calibration standard of moderate accuracy (approximately 5%) for low-field (<0.5 kA/m) magnetic susceptibility measurements. The use of powders allows fabrication of standards of nearly any shape and size. For our mixtures, which range from 0.063 to 11.8% iron oxide by weight, the susceptibility values vary from 2.65 x 10(-7) to 5.77 x 10(-5) m3/kg, and are nearly linear with iron oxide concentration.     

A functional approach for standard component reuse

This paper proposes a novel approach for standard component reuse in die design. In this approach, a standard component, or a subassembly of standard components, is represented by a unique name called the order name. The order name is derived by combining a manufacturer or supplier's name with the catalogue name used for ordering components from the supplier. In this system, the standard components are classified according to their generic information, i.e. their functions and the geometrical characteristics of their mating relationships with other components. When a user designs a particular die structure for a certain function, some design options and requirements are inputted. Using this information, the generic information of the standard component is derived and the order name is selected. The rules required for the selection procedures are stored in a knowledge-base shell. The shell is able to search data tables and retrieve parameters regarding the standard components. In this approach, the catalogue data and selection procedure are independent of the design system. It is concise and consistent with industry practice.     

氢化物发生原子荧光光谱法测定水中痕量锑

采用氢化物发生原子荧光光谱法测定水中痕量锑。用盐酸和5%硫脲+5%抗坏血酸混合溶液处理样品,并以1.0%硼氢化钾和0.5%氢氧化钾为还原剂,在5%的盐酸介质中测定锑,锑的检出限(DL)为:0.028 μ g/L,相对标准偏差RSD (n=15)为3.1%,水样的加标回收率在94.3%～103.6%之间。本方法具有操作简便、快速、基体干扰少、灵敏度高和重现性好等优点,可用于水样中锑的测定。     

Design and development for amelioration of primary water flow standard and calibration systems

The present study outlines the efforts made to improve national primary water flow standards and calibration systems through design and development. The facility has been designed and developed in accordance with ISO 4185 standard in the flow range 0.03 m³/h to 650 m³/h to calibrate various types of flow meters up to DN200 (Nominal diameter) using 12 kg, 300 kg, 3000 kg, and 6000 kg weighing systems. In the flow range up to 530 m³/h, the expanded uncertainty in flow meter calibration in totalized mode is found to be ±0.01% to ±0.025% (k = 2), whereas it is ±(0.03–0.05) % (k = 2) up to DN200 size (test rigs) for mass flow rate (MFR) and volume flow rate (VFR) in the flow range 0.1 m³/h to 650 m³/h. The measurement uncertainty achieved is comparable to that of state-of-the-art water flow measurement capabilities available at numerous National Metrology Institutes (NMIs). Thus, the present designed and developed system at CSIR-National Physical Laboratory (CSIR-NPL) is a solution to maintain traceability to the users and industries.     

含油废水处理用动态水力旋流器构件设计研究

为适应油田含油废水处理设备的小型化、可移动的需要，从提高动态水力旋流器设计及制造精度入手，运用数学、流体力学、三维CAD造型技术等知识，对其主要构件，如转筒、旋转栅、溢流口等进行了优选设计和试验对比分析。为制造分离性能优良的样机提供了理论指导，也为其深入研究奠定基础。     

HPLC法测定饮用水中的甲醛残留

本实验在加酸加热的条件下,水样中的甲醛与氨比西林直接反应,用乙醚提取反应产物,用反相高效液相色谱分离荧光检测器检测。甲醛在0．1～2．0μg／ml的浓度范围内线性相关系数达0．999以上,检出限可达0．01μg／ml,相对标准偏差（RSD）为0．65％,加标回收率为95．7％～106．0％。     

催化荧光法测定环境水样中痕量对苯二酚

在H2SO4介质中,痕量对苯二酚对溴酸钾氧化二氯荧光素(DCF)的反应具有显著的催化作用,据此建立了催化荧光法测定水样中痕量对苯二酚的新方法。在最佳测试条件下,荧光强度降低值(△F)与对苯二酚浓度在0~1.0μg/mL范围内呈良好的线性关系,方法的检出限为0.037μg/mL。该方法可用于环境水样中痕量对苯二酚的测定,结果满意。     

直接荧光光度法测定水中痕量酚

建立一种新的荧光光度法分析水中痕量酚。水中的酚经紫外光照射后,激发强荧光(λex=273nm,λem=302nm)能直接进行荧光光度测定。检出限0.03μg·L~(-1),相对标准偏差0.29％,回收率97.5％～102.5％。方法简单、快速、精密度和准确度高、无毒、安全。     

毛细管气相色谱法测定污水中氰乙酸甲酯

建立了采用醋酸乙酯－石油醚萃取,大口径毛细管气相色谱法测定污水中微量氰乙酸甲酯的分析方法。该法的平均回收率为93．4％,RSD不大于5％。方法简便,快速,准确。