Kalibrierung von Schnüffel‐Testlecks

Calibration of reference leaks for testing leak sniffers Functionality, safety and environment protection require the tightness of equipment against atmosphere. To check for possible leaks, commercial leak sniffers are commonly used. In order to warrant the reliability of leak testing, the sniffers must work properly with correct sensitivity at usage. To prove the proper operation of the leak sniffer, test leaks with known leak rates are used. The present paper deals with design and calibration of the test leaks, in particular for very small leakage.     

金属压扁型正压漏孔不同压力下的漏率研究

在不同入口和出口压力条件下,正压漏孔的漏率值会发生变化,在使用时需要对正压漏孔的校准值进行修正。对2支金属压扁型正压漏孔在多种压力条件下进行漏率测量,给出了测量结果,然后根据管道流导理论推导出正压漏孔漏率随压力变化的修正公式,并对修正结果与实验测量数据进行了研究分析。     

恒压式气体微流量计测量不确定度评估

介绍了恒压式气体微流量计的组成和校准原理.在对电容薄膜规做了热流逸效应实验的基础上,对流量计的测量不确定度进行了评估,给出了扩展不确定度和包含因子.通过传递标准漏孔与德国PTB开展了漏率比对,验证了测量不确定度评估结果的可靠性.     

比较法真空标准漏孔校准方法研究

比较法校准真空标准漏孔是通过四极质谱计比较气体流量计提供的标准气体流量与被校真空标准漏孔产生的离子流获得校准值。主要介绍了比较法真空标准漏孔的校准方法、装置原理、校准过程及校准结果的处理等,并提出了减小测量不确定度的影响因素。     

Helium‐Testlecks zur Kalibrierung von Lecksuchern

In order to perform reliable quantitative measurements of leak rates, the used leak detection equipment is calibrated by injection of a known leakage flow delivered by a test leak. Well‐proven are Helium test leaks of the diffusion type with internal gas reservoir. The present paper deals with the construction of such leaks, the temperature dependence and response time of the leak rate, and their calibration. In case of careful handling, the relative uncertainty of the delivered leakage flow can amount to only 3 % (2σ).     

氦质谱检漏仪现场校准方法研究

目前,用户采用单只标准漏孔对氦质谱检漏仪进行校准,由于受检漏仪线性范围的影响限制,不能对其全量程范围进行校准。为了满足对氦质谱检漏仪全量程范围内的现场校准,将一系列不同量级漏率的薄膜渗氦型标准漏孔分别接入氦质谱检漏仪,得到一组标准漏孔检漏仪示值,通过对标准漏孔漏率值与检漏仪示值的关系曲线进行数学拟合,得到氦质谱检漏仪全量程测量范围示值与漏率值之间的拟合公式。其校准过程简单,能够提高氦质谱检漏质量。     

冷媒气体泄漏率的定量分析

工业上一般使用标准漏孔对冷媒检漏仪进行定性检测,由于它的便捷性而得到广泛使用。近年来,对标准漏孔的溯源方式和校准方法进行探索逐渐进入人们的视野,冷媒气体泄漏率的定量分析和测量过程的不确定度评估定量分析就显得尤为重要。通过建立数学模型,对标准漏孔在测量过程中影响测量不确定度的因素进行分析和量化。最后通过实验验证,测量结果的相对扩展不确定度约为4%,可以满足了泄漏率量值传递过程中10%的要求。     

X射线剂量当量仪校准因子不确定度评估

为了准确评估X射线剂量监测用防护仪表的校准因子的不确定度,依据有关技术规范,用标准电离室对参考点位置处的剂量当量率参考值进行测量;采用替代法获得待校仪表的显示值,从而确定校准因子结果的相关影响因素,并分别对影响量的不确定度进行评定;得出仪表校准因子的相对扩展不确定度为5.0％(k=2)。影响校准因子不确定度的主要来源包括校准用辐射场的均匀性、标准电离室本身的刻度因子及能量响应、剂量当量转换因子、待检仪表显示值的统计标准偏差等。在对该类仪表的校准过程中,通过提高标准参考值的不确定度水平可以改善校准因子的不确定度。     

恒压法校准正压漏孔的测量不确定度评定

为评定恒压法校准正压漏孔的测量不确定度,建立恒压法正压漏孔校准结果测量不确定度评定的数学模型,分析不确定度各影响分量及其灵敏系数,由恒压法校准正压漏孔的A类标准不确定度评定及B类标准不确定度评定,计算出恒压法校准正压漏孔的相对扩展不确定度,并通过实验给出恒压法校准正压漏孔的测量不确定度评定示例。     

A New Calibration Apparatus of Port Quick Leak Detector for Spacecraft

The leak rate of spacecraft port must meet certain standards during the opening and closing processes. The port quick leak detector can be used to on-line measure leak rates of spacecraft port. In this work, a new calibration apparatus is designed and investigated. It can work at different temperatures with different gases in a wide leak rate range. This apparatus consists of the standard leak rate system, calibration system, temperature control system, gas supply and pumping system, which is designed on the basis of direct comparison calibration method and pressure-rising method with a constant volume, and the leak rates are provided by the standard leak rate system. The calibration range of the calibration apparatus is from 2 × 10 ^–6 to 2 × 10 ^–2 Pa m³/s. Its combined standard uncertainty is about 4.7%, and its calibration temperature is from ? 50 to 20 °C. Within the above leak rate and temperature ranges, the correction factor of the port quick leak detector is about 0.88–1.09.     

用锌凝固点和水沸点检定二等标准铂电阻温度计的扩展不确定度评定

按时规范,ＪＪＦ１０５９－１９９９,对二等标准铂电阻温度计在锌凝固点及水沸点检定的不确定度进行了评定,通过建立测量数学模型确定各标准各不确定度分量,并按不确定度传播公式给出固定点间各温度点的扩展不确定度及包含因子。     

微风速标准装置的建立和热线风速仪校准方法的实验研究

中国计量科学研究院建立了微风速标准装置,基于该标准装置对热线风速仪的校准展开了实验研究。微风速标准装置基于相对法测量原理,实验通过气浮滑车搭载热线风速仪运动,由激光干涉仪测得的距离对时间微分得到标准速度,通过这种方式实现了热线风速仪的校准。滑车的运动速度可以溯源到国家计量院的时间和长度基准;此外,根据热线风速仪传感器的理论模型计算得到了热线风速仪的静态特性方程,比较理论模型与校准结果,发现二者具有良好的一致性。实验结果和不确定度分析表明:微风速标准装置的扩展不确定度U=0.82%（k=2）;热线风速仪校准结果的扩展不确定度U=2.42%（k=2）。     

1000V多盘感应分压器标准建立

中国计量科学研究院研制了一台1000V多盘感应分压器标准装置,用作工频1000V电压比例标准。该装置使用了一种基于互感器注入的误差补偿技术,可准确提供从1×10^-8到1的宽范围比例出。感应分压器的误差校验使用了包含三同轴屏蔽技术的改进型参考电势增量法,并设计了多比例参考互感器以便对感应分压器进行整体校验。所研制的感应分压器准确度优于1×10^-7,校准结果不确定度小于2×10^-8。     

压漏孔校准装置性能测试

正压漏孔校准装置可采用定容法和定量气体动态比较法进行正压漏孔的校准。定容法的校准范围是１００～５ × １０~（－３） Ｐａ· Ｌ／ｓ,不确定度小于９．１０％;定量气体动态比较法的校准范围是１×１０~（－２）～５×１０~（－５）Ｐａ·Ｌ／ｓ,不确定度小于１４．２０％。     

标准静态膨胀法真空装置研制

本装置检定范围(10^-3～10^5)Pa，最佳校准能力0．012％～2．2％．可以检定薄膜真空计。热传导真空计以及电离真空计。该装置的建立不仅满足了从大气到10^-3Pa高真空计量的需求，而且还可以用来校准标准漏孔，拓宽了检测领域。     

Prüflecks für Schnüffel‐Lecksucher

In the testing of leak tightness and in the localisation of leaks by means of a test gas, proper operation and sensitivity of the employed instrument must be checked by a certified reference leak. In the so‐called sniffer mode of operation, the component under test is filled to overpressure with the test gas, so that in case of a leak there is a gas flow from the component to atmosphere. The atmospheric gas is sucked by the instrument and probed for its test gas content. For checking the instruments performance, commercial test leaks are available for various gas species, which deliver a well‐defined leakage. Construction and properties of such a test leak are described. The leak has an internal gas reservoir and a capillary as leak element. Because the inlet pressure at the capillary is kept constant by a pressure controller, the leakage remains constant over several years despite the gradual pressure decrease in the gas reservoir. The calibration of the leakage via the volume flow rate is described in detail. The volume flow rate can be measured by a liquid drop in a measuring capillary as well as a displacement piston in a dosing syringe.     

中俄标准水听器在0.01～1Hz频段的双边比对校准

叙述中国杭州应用声学研究所和俄罗斯全俄物理技术与无线电测量科学研究院的标准水听器在0．01～1Hz频率范围内的双边比对校准方法和结果。在15个频率点上双方分别对5个不同水听器测得的开路电压灵敏度之差的平均值最小为0．02dB,最大也只有0．21dB,远小于双方合成的总扩展不确定度,这证明了两国在此频段内的水声声压标准装置都有很高的准确度。     

Evaluation of laboratory performance through interlaboratory comparison

This paper reports the performance of the calibration results obtained by 21 laboratories using digital pressure calibrator as an artifact in the pressure range 7–70 MPa. National Physical Laboratory (NPLI), New Delhi has coordinated this programme and also acted as a reference laboratory. The program started in May, 2006 and completed during May, 2008. The comparison was carried out at 10 equally spaced pressure points i.e. 7,14,21,28, 35,42,49,56, 63 and 70 MPa throughout the entire pressure range of 7–70 MPa. The calibration results thus obtained were analyzed as per ISO / IEC GUM document. The 92.7 % measurement results are found in agreement with the results of NPLI. The relative deviations between laboratories values and reference values are well within the 0.05 %for 123 measurement points, 0.1% for 162 measurement points and 0.25% for 177 measurement points. The difference of the laboratories values with reference values are found almost well within the uncertainty band of the reference values at 68.0 % measurement results, within their reported expanded uncertainty band at 81.5% measurement results and within the combined expanded measurement uncertainty band at 92.7 % measurement results. Overall, the results are considered to be reasonably good being the first proficiency testing for most of the participating laboratories.     

Stabilität der Leckrate von Helium-Testlecks

The stability of the bak rate of Helium test leaks For the sensitivity calibration of Helium leak detectors, test leaks with known Helium throughput are used. Widespread is the type of test leak with internal gas reservoir from which the gas is delivered by permeation through a wall. In case of constant temperature, one expects a constant gas throughput except for a gradual minor decrease due to gas loss (typically ?1% per year). This behavior is in fact found for test leaks with quartz wall. In contrast, substatial scattering is observed for test leaks with plastic wall which is not yet understood. In the paper also reaction times of the leak rate on changes of temperature and reservoir pressure are reported for test leaks with quartz and plastic wall.