JJF1376-2012《箱式电阻炉校准规范》有关问题的探讨

正JJF1376-2012《箱式电阻炉校准规范》适用于工作温度不高于1300℃的箱式电阻炉(以下简称"箱式炉")的校准。给出的计量特性指标有炉温均匀度、炉温稳定度、炉温偏差和炉内最大温差。计量特性的校准通常是在空载状态下进行,按JJF1376-2012规定布置测温点。当炉温达到校准温度,并处于热稳定状态后开始读数。在60min内,每隔3min记录各个测温点的     

井式电阻炉炉温均匀度校准方法探讨

井式电阻炉是热处理生产工艺中常用的炉子,其炉温均匀度直接关系到企业的正常生产和产品质量的保证。因此,定期对井式电阻炉的炉温均匀度进行校准是十分必要和迫切的。     

箱式电阻炉的检测方法

对于箱式电阻炉控温系统温度参数的检测,遵照现行的国家规程只能对控温系统各个元件分别进行检定.但采用分立元件法检定热处理用控温系统的误差,无法满足热处理行业大部分工艺要求.例如,若工厂购入的热电偶未经检定就直接使用,会使分散性很大,所测数据不可靠,不能用于指导生产.如何对箱式电阻炉用统一的技术手段和方法对其整体进行计量性能评价,使之具有横向可比性,为箱式电阻炉的生产和使用提供技术支持,已成为亟待解决的一个课题.本文通过对现有国家标准和国际上常采用的测试规范,结合计量系统的实际应用,给出了在实际检测箱式电炉控温系统中比较科学、实用的检测方法,使得统一箱式电阻炉生产部门、使用部门、计量部门对其计量性能整体评价的需求成为可能.     

箱式电阻炉温度场参数的校准及其不确定度评定

本文主要针对日前箱式电阻炉温度场参数的校准无国家校准技术规范与我省无地方校准规范,而技术机构现已开展箱式电阻炉温度场参数的校准,但采用的依据与方法不统一,因此本文根据实际情况提出箱式电阻炉温度场参数的校准及其测量小确定度的评定,作为我省存开展箱式电阻炉温度场参数的校准使用与参考。     

基于箱式电阻炉的智能采集软件设计与应用

目前箱式电阻的计量校准工作主要采用手工采集方式,在环境温度补偿和修正值补偿上复杂繁琐,参数计算费时费力且出错率高。本文基于KEIYHLY 2700数字多用表作为硬件平台设计了一款新型高温采集软件,对炉膛的温度信息进行实时采集、参数计算和报告生成。通过与常规手工采集方式进行对比试验,结果表明炉温各参数的绝对误差都分布在(0. 01～0. 03)℃。因此,将智能软件采集方式应用于箱式电阻炉的校准工作,能够很好地满足现场电阻炉的校准需求。     

浅析烘箱校准过程中温度偏差的修正方法

本文对烘箱校准过程中温度偏差的修正方法进行了总结,并通过说明为计量工作着提供便利。     

箱式电阻炉校准过程中的误差分析

箱式电阻炉作为常规加热设备,以电能为主,通过热传导、热辐射等方法实现热量的传递。具有体积小、速度快、损耗率低、操作维护简单的特点。在国内工业生产、科研机构中应用广泛。本文针对电阻炉校准环节中的方法、误差起因及主要应对策略等进行了全面分析,旨在提高箱式电阻炉的实际应用价值。     

改善二位式调节仪表控制炉温精度方法探讨

本文对实验室所使用的恒温箱和高温炉采用二位式温度调节仪控制炉温,提出在不增加用户较大成本的情况下来改善炉温温度波动度、温度均匀性、温度偏差的几种方法。     

对JJF 1376-2012的几点建议

<正>0引言箱式电阻炉具有体积小、升温快、热损小、均匀性好、维修方便、使用安全等优点,目前广泛应用于化学分析、物理测定、钢件热处理、高温灭菌等方面。JJF 1376-2012《箱式电阻炉校准规范》的发布实施,填补了之前对箱式电阻炉校准方法的空白,为评价箱式电阻炉准确度水平提供了一个很好的参考标准。不过在校准测试过程中,遇到了各种各样的问题。本文将结合实际工作,对规范中存在的一些不足之处进行阐述,并提出改进建议。1部分细节不够严谨和规范     

炉温测试仪校准方法的探讨

炉温测试仪主要用于测量波峰焊、回流焊等设备的测温曲线,以便更好的改进制程和工艺。文章简述了炉温测试仪装置的结构和使用,对炉温测试仪的校准方法进行探讨,并通过试验数据和不确定度评定验证方法的可行性以及指出了注意事项。     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.     

Estimation of potentialities of methods of summation of direct measurement errors

Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995.     

空压机轴承箱蜗壳温度探头油封改造

由于空压机进气侧轴承箱蜗壳温度探头密封效果不好,使空压机及其后续管道受到油污染。后将温度探头的O形圈密封改为骨架油封,杜绝了轴承箱漏油问题。文章简介空压机的结构和技术参数,详细介绍了骨架油封的制作和优点。     

Characteristics of mechanical properties of materials in studies of conditions of attainment of marginal states

It is shown that conditions of attainment of marginal states in the material of structural components are formulated on the basis of analysis of force and deformation criteria of formation and development of destruction. The parameters of these criteria are data on types of structural materials, standard and special characteristics of their mechanical properties, structural forms of considered elements of the equipment, and their operating stress loading. In this case, the construction of a system of state equations for describing interrelation of current damage, external actions, and responses to them is based on the concept of calculating variations in properties of materials at all stages of the design life cycle.     

Determination of parameters of microstructural inhomogeneity of deformation of metals by the method of modeling

The article suggests a method of evaluating the microstructural inhomogeneity of deformation of metals by modeling. The method includes the measurement of deformations of metal according to meshes of a dividing grid with small base and the calculation of the distribution parameters of microdeformations in model representation. It is shown that the modeling method makes it possible objectively to evaluate the microinhomogeneity of deformation of metals independently of the chosen mesh size of the dividing grid. New structural characteristics are introduced: the base and wave of variation expressing the degree of crumbling or amalgamation of metal grains by inhomogeneity of deformation.Translated from Problemy Prochnosti, No. 7, pp. 40–44, July, 1991.     

水三相点复现的不确定度评定

水三相点是开尔文热力学温度的唯一基准点，也是ITS-90国际温标重要的定义固定点。因此，水三相点不确定度分析对整个温标的建立、温度量值传递起着至关重要的作用。近3年来，中国计量科学研究院研制出一系列高质量的水三相点容器，加强了水三相点的研究，为不确定度的分析提供了更为可靠的实验依据。同时，不确定度的分析也是客观评价新研制容器性能的一个重要指标。因此，根据实验结果对新研制容器所复现的水三相点进行了不确定度评定。评定结果表明，其扩展不确定度为0．16mK(k=2．69，P=0．99)。