粉尘浓度监测仪校准技术发展概况

<正>一、粉尘浓度监测仪概述目前,国内外使用的粉尘浓度监测仪种类较多,但依其工作原理主要有以下4类:粉尘采样器、光散射式粉尘测试仪、β射线测试仪、微量振荡天平测试仪。粉尘采样器是使用滤膜采集粉尘样品,通过称重和计算得出粉尘浓度值。由于该测试方法准确、可靠,被很多国家定为粉尘浓度测试的基准方法,但该方法需要称重、烘干、采样、再烘干、再称重及计算等一系列繁琐的过程,不能及时反映现场环境的粉尘污染状况,同时也不能反映挥发性粉尘污染状况。后3类仪器属     

光散射式数字粉尘测试仪的标定及测量结果分析

光散射式数字测尘仪是一种快速、准确的测尘仪,它因性能稳定、灵敏度高,且测量方便而得到广泛的应用。光散射式数字粉尘仪的相对误差是用校准粒子来检定的。测量结果是粉尘的相对浓度,在实际中要将相对浓度转化为质量浓度,才能得到粉尘的实际浓度。     

粉尘性质对光散射式粉尘仪测量结果的影响

JJG 846—2015粉尘浓度测量仪检定规程规定了可以使用多种粉尘粒子对粉尘仪进行计量检测,但是粉尘性质差异对光散射式粉尘仪检测结果的影响并没有引起重视。通过对某台TSI光散射式粉尘仪的检测,发现亚利桑那尘和细化煤粉测量结果差近4倍。颗粒物密度越大,粒径越大,颜色越深,测量灵敏度越低,质量浓度转换系数K值越大;其中色泽影响最显著。由于K值对粉尘材质、色泽、粒径分布的高度依赖性,要求光散射式粉尘仪根据测量场合、季节、气候的变化,经常修正K值,以保障测量结果的准确性。     

对光散射式粉尘测试仪的标定及其不确定度分析

依据JJG846-1993《光散射式数字粉尘测试仪检定规程》,采用KCl气溶胶对光散射式数字粉尘测试仪进行溯源性标定,对该检定规程加以拓展,用多分散气溶胶代替单分散气溶胶,并根据误差传播定律建立不确定度计算的数学模型,以及对测量结果的不确定度进行A类和B类评定,实验结果表明KCl气溶胶发尘稳定,适宜作为实验校准中的标定尘源。     

粉尘浓度测定仪示值误差校准不确定度评定

文章介绍了粉尘浓度测定仪工作原理,以某光散射式粉尘浓度测定仪为例,依据JJG 846—2015《粉尘浓度测量仪》检定规程对该粉尘浓度测定仪进行了校准,并对其示值误差校准不确定度进行了评定。     

光散射式粉尘浓度测定仪示值误差测得值不确定度的评定

依据JJG 846-2015《粉尘浓度测量仪检定规程》及JJF 1059.1-2012《测量不确定度评定与表示》,对光散射原理仪器按规程要求的各校准点示值误差测得值不确定度进行了评定,评定过程真实有效,可为相关机构技术人员在检定/校准光散射式粉尘浓度测量仪中评定示值误差测得值的不确定度提供参考。     

光散射粉尘仪的计量性能评价

光散射粉尘仪示值误差指标,不仅受K值是否与被测颗粒物匹配影响,还受线性、截距和K值可调空间三要素影响,仪器线性越好,截距越小,K值可调空间越大,则光散射粉尘仪性能越好。通过不同浓度下,被检粉尘仪和参考粉尘仪建立的工作曲线,其斜率b可作为光散射粉尘仪复现性的一个考察指标。利用该指标研究了温度对光散射粉尘仪的影响,结果表明,-10℃和40℃的温度条件下,曲线斜率b的复现性无显著差异,测量方式对测量结果没有显著影响,这是由于这些仪器传感器进行温度保护或补偿,从而保障在高低温环境条件下粉尘仪的性能可靠性。     

激光光散射法在超细粉粒度测试中的应用

介绍了激光光散射的基本原理及其在粉体测试领域中的应用,分析了激光粒度测试仪的基本组成和工作原理,通过不同仪器间粒度测试的对比实验及准确度,精密度实验,并对误差进行了分析,指出激光光散射法是一种高效,快速、准确的现代粒度测试方法。     

湿度对光散射粉尘仪测量结果的影响

光散射式粉尘仪测量结果不仅受颗粒物性质影响,还受湿度影响。这是由于水气在颗粒物表面凝结,会改变颗粒物尺寸、形状、折射率,从而改变颗粒物光散射能力。当相对湿度大于60%RH时,湿度对光散射测量增强作用不可忽略。一方面,可通过半经验公式对湿度影响进行修正,但应用有限;另一方面,通过加热、稀释、Nafion膜等一种或多种技术相结合进行除湿,其中加热除湿是被广泛采用的技术。     

光散射法颗粒物监测仪粒径识别检测装置的搭建及方法研究

设计并搭建了粒径识别法光散射粉尘仪检测装置,以柴田LD-5型光散射粉尘仪作为参考粉尘仪(TSP),采用不同粒径(0.6,2.0,2.3,2.5,2.7,3.0,3.2,3.4,3.7 μm)的单分散聚苯乙烯小球对某台具有粒径识别功能的PM2.5传感器的粒径识别误差进行检测.如果传感器粒径识别功能是准确的,当粒径＞2.5...     

Mobility measurements by phase analysis

A new instrument, based on the principle of phase analysis light scattering (PALS) for the measurement of electrophoretic mobilities, has been produced. Such measurements are particularly useful in the study of dispersions in nonpolar and highly conducting media. The current PALS configuration can be used to measure mobilities up to 3 orders of magnitude lower than with the conventional Doppler mode. The device has a number of new features; in particular, all the signal processing is digital and the optical system features a reference beam configuration. Data are presented to show that on suitable samples both the PALS technique and conventional laser Doppler electrophoresis can be performed on the same instrument and the techniques are in good agreement.     

基于SoC的动态参数记录仪微型化研究

存储测试的主要特点是测试仪器置于被测对象内部或被测环境中实时地获取动态参数,为了减小测试仪器对被测对象的影响,需要减小测试仪器的体积,实现测试仪器的微型化.针对存储测试仪器的微型化需求,提出利用SoC系统集成、模块化结构等技术,将数字电路的ADC模块、控制模块、存储模块、接口模块等集成在专用SoC芯片中,同时,将测试电路分为模拟电路、SoC数字电路、电池等模块,立体封装在机械壳体里,设计并实现了微型化的动态参数记录仪.基于SoC的微型化动态参数记录仪体积约10 cm³,可以嵌入被测体内或者置入被测环境中,实时获取相关动态参数.试验表明,基于SoC的微型动态参数记录仪可以用于应变、侵彻加速度、火炮膛内压力等动态参数的测试.     

Physics of Hard Spheres Experiment: a general-purpose light-scattering instrument

A general-purpose, multifunction light-scattering instrument has been developed at the NASA Lewis Research Center for Space Shuttle and Space Station colloid crystallization and other microgravity experiments. For a single sample, the instrument can measure two-dimensional Bragg scattering from 0.5 degrees to 60 degrees , dynamic and static light scattering from 10 degrees to 170 degrees , the shear modulus of samples before and after crystallization, and digital color images of the sample. A carousel positions any one of eight 3-ml samples into the test position for separate experiments. Program challenges and flight results from the STS-83 Space Shuttle mission are discussed.     

数字微波通信综合测试系统

数字微波通信综合测试仪是将十几台仪器的测试功能集成在一个测试系统中。它可以对数字微波通信系统的大部分参量进行测量 ,特别适合于数字微波移动通信系统的测量。本文简要介绍了数字微波通信综合测试仪的原理和应用。     

污染扩散瞬时浓度场测量方法的研究

提出了一种以粒子成像、粒子散射和统计光学为理论基础的污染扩散非定常瞬时浓度场的测量原理,设计了大范围瞬时浓度场测量系统,利用该系统对瞬时扩散的浓度场进行了实际测量,通过数字图像分析和处理得到污染扩散的非定常瞬时浓度场。     

Optical particle sizing in backscatter

Several possibilities for the use of elastic light scattering in the backscatter range (scattering angle theta(s) > 140 deg) for determination of size, velocity, and refractive index of spherical particles are investigated. First the phase Doppler technique is considered. Numerical simulations of light scattering with the Lorenz-Mie theory are used to show that the phase Doppler technique is unsuitable for such backscatter configurations, except for special measurement conditions. The time-shift (or pulse-displacement) technique is then considered by use of the Fourier-Lorenz-Mie theory. Simulations show that up to four fractional signals can be obtained by use of the technique in backscatter, corresponding to the scattering order or modes: surface wave (long path), reflection, second-order refraction (inner path), and a mixture of second-order refraction (outer path) and surface wave (short path). Signal characteristics as a function of particle size, refractive index, and particle ellipticity are studied. Suggestions for a practical measurement instrument are put forward.     

多角度动态光散射法的纳米颗粒精确测量

基于动态光散射原理,采用自主研发的多角度动态光散射装置,对纳米及亚微米颗粒粒径准确测量方法进行了探究。自研装置采用带有光阑组的精密入射光路设计,以及匹配液池及Beam-stop设计,极大提高了信噪比;同时避免了测量角度的互补方向上,由于样品池与空气界面折射率不同导致的反射光信号对有效信号的干扰。在此基础上,对不同浓度、粒径的聚苯乙烯(PS)颗粒溶液进行了测定及不确定度分析。结果表明,对同一粒径的PS颗粒,增加颗粒浓度时,多重散射首先发生于大、小测量角度,越接近90°,发生多重散射的浓度越高;随着粒径增大,受不可忽略的颗粒间相互作用的影响,粒径测量结果表现出了强烈的角度依赖性,甚至波动性。     

基于图像处理测量露天爆破粉尘量

以缅甸莱比塘铜矿为研究对象,开展露天爆破粉尘测量方法的研究。采用数码相机对爆破粉尘进行摄影,获取了不同浓度粉尘图像灰度值数据,通过对粉尘浓度实际测量,建立了粉尘浓度值与图像灰度值的数学关系,分析粉尘图像灰度特征获得了粉尘浓度空间分布规律,计算得到起爆后某一时刻爆区空气爆破粉尘总量。研究结果表明:爆区正侧方50m处起爆后96s内平均粉尘浓度为1 602mg/m³;粉尘浓度与粉尘图像灰度的比例系数k为9.117mg/m3;粉尘浓度与粉尘图像灰度的比例系数k为9.117mg/m³;起爆后30s时形成粉尘体的浓度由内向外逐渐降低,边缘浓度急剧降低,宽度方向浓度近似相等;起爆后30s时空气中爆破粉尘总量为864.91kg。     

Software for personal instruments

When a personal computer (PC) is used as the computing system of an intelligent instrument, software devoted to measurement process control and to measurement process outputting can be specially developed to assist the operator throughout the measurement process in a friendly way. When these conditions are met, the intelligent instrument is called a personal instrument (PI). The main features of a PI are discussed, and the requirements for PI software are given. The performance of an original software package for PI is illustrated, showing how all the requirements are satisfied. This software, coupled to a good commercial data acquisition system, features high-precision measurement and a high level of friendliness and can be useful for lab tests and educational purposes. For lab tests, this software is a good basis for an automatic test station with extended help facilities. It ensures better performances than that of a digital scope because it allows dedicated measurement routines to be developed and executed. The software is effective for educational applications, since it allows direct application of all capabilities offered by computers in instrumentation, when associated with suitable A/D (analog/digital) conversion hardware     

空腔式β射线粉尘测量仪的可行性研究

文章阐述了在粉尘浓度在线连续监测中发挥了独特优势的空腔式β射线粉尘测量技术的工作原理、系统结构及理论模拟结果,研究了空腔式β射线粉尘测量仪在粉尘监测中可能的使用效果,提出了研制测量仪的理论方案。