温度计自动检定

文章介绍一种新的温度计自动检定系统模型与计量管理一体化在温度计自动检定中的应用，使得自动检定系统可以与企业数据库联系起来。     

工业温度计综合自动检定技术研究

工业温度计广泛应用于工业生产和科研试验中,实现对工业温度计的自动检定,可提高工作效率,提高检定质量,提升计量技术水平。文章介绍一种工业温度计自动检定系统,能同时实现多种工业温度计自动检定,自动处理数据,自动打印证书报告,符合各类工业温度计检定规程的要求。     

计量管理一体化在温度计自动检定中的应用

本文介绍一种新的温度计自动检定系统模型 ,将计量管理一体化在温度计自动检定中的应用 ,使得自动检定系统可以与企业数据库联系起来     

基于机器视觉的玻璃液体温度计自动检定系统研究

本文提出了一种基于机器视觉的玻璃液体温度计自动检定系统。根据机器视觉的工作原理,设计了玻璃液体温度计自动检定系统的体系结构;介绍了温度计图像预处理和图像二值化分割方法,重点研究了针对玻璃液体温度计图像温度示值识别的穿线法和投影法。     

标准铂电阻温度计自动检定计算方法

根据国家计量定规程,针对标准铂电阻温度计自动检定的要求,设计出一套自动检定计算算法。该计算算法已用在实际的标准铂电阻温度计自动检定系统中,被证实时切实可用的。     

一等铂电阻温度计标准装置智能检定系统

一等铂电阻温度计标准装置主要用于检定二等标准铂电阻温度计,检定程序繁琐、计算量大,迫切需要改进目前的装置,实现标准铂电阻温度计的智能检定。本文系统是对传统一等铂电阻温度计标准装置的智能升级,优化了标准铂电阻温度计的检定过程,能自动采集数据、自动处理数据,能生成证书内页及分度表。     

水银温度计视觉检定系统中的数字图像处理技术研究

提出了一种基于计算机视觉的水银温度计自动检定系统。首先构建了水银温度计自动检定系统的体系结构,重点研究了数字图像处理技术在温度计读数上的应用,研究了直方图均衡化处理,并根据OTSU原理,把温度计图像进行分割,采用Canny算子提取温度计边缘,并根据Hough变换得到温度计刻度线和液柱,最后给出了与人工读数对比的实验结果及结论。     

基于F18高精密电桥的温度计自动测量检定系统

本文介绍了在F18高精密电桥基础上，利用Visual Basic6．0，Access2000、Microsoft Excel及水晶报表为主要开发工具，以Windows为开发平台设计了一套完善的温度计自动测量检定系统。实验验证该系统提高了测量准确度及温度计检定的工作效率。     

玻璃液体温度计自动检定装置研制

运用了目前国际上成熟的控温技术、CCD摄像技术、图像处理技术和计算机信息处理技术,研制了技术性能优于JJG130-2011《工作用玻璃液体温度计》检定规程要求的温度计检定系统,实现了温度计的自动检定和数据处理,检定结果不确定度优于人工检定.     

适用于特高压变电站的压力式温度计自动检定技术研究

文中提出压力式温度计自动检定系统的构成,还详细介绍了检定系统的使用方法。该自动检定系统相对于以往的检点系统操作起来更加方便,检定的准确度也得到进一步提升。     

基于VBA的工业铂电阻半自动校准系统

介绍一种在Excel内嵌的VBA平台上开发的工业铂电阻半自动校准系统,对系统的工作原理及软件流程进行了论述,通过程序实现了判断恒温槽温场变化、自动记录铂电阻阻值数据、在校准(检定)完成后对铂电阻进行自动等级判定、自动生成原始记录和证书等功能,解决了以往工业铂电阻的校准(检定)工作中遇到的数据量大,后期处理繁琐的问题,具有推广价值。     

基于LabVIEW实现固定发射率辐射温度计校准的温度修正

在辐射温度计检定中,根据规程要求,需要将辐射温度计的发射率设置为1,而在实际校准辐射温度计的过程中发现大量发射率固定且不为1的情况,同样有用户要求校准后给出不同发射率下的辐射温度计修正值,为实现宽波段任意固定发射率辐射温度计在校准过程中的修正值计算,文章使用LabVIEW的两分法迭代实现Plank公式的积分算法,有效提高校准过程的自动化程度,文章用实例说明了两分法与普通步进算法的效率区别,从而高效的实现了任意波段、任意发射率、任意温度点的温度修正值计算。     

Calibration of Air Thermometers in a Climatic Chamber and Liquid Baths

The paper deals with calibration of digital indication thermometers designed for air temperature measurements. These were calibrated by comparison with a reference thermometer in two different calibration media: in the air when a climatic chamber was used and in a liquid when a calibration bath was used. The main difference between the media was thermal conductivity, which was more than ten times lower in the air. To compare both methods, we calibrated two sets of air thermometers twice. The first set comprised of small temperature loggers with an internal sensor, whereas the second set was a group of temperature probes connected to the measurement unit. The temperature ranges for the loggers were from 0 \(^{\circ }\)C to 40 \(^{\circ }\)C and for the probes from ?20 \(^{\circ }\)C to 60 \(^{\circ }\)C. The results showed that the measured temperature errors were smaller in the bath as well as less scattered. Furthermore, the assigned measurement uncertainty was lower, if calibration was performed in a calibration bath, mostly due to better thermal homogeneity of a liquid compared to the air in a climatic chamber. Calibration shall assure traceability of a measurement equipment in such a way that a calibration procedure simulates an actual use of equipment; otherwise, the corrections and associated measurement uncertainty could be misleading. Therefore, when air thermometers, which are designed to measure a gaseous medium, are calibrated, they should be calibrated under similar conditions as they are used. The paper presents the differences in results of calibration of air thermometers under different calibration conditions.     

Development of a System for Temperature Profile Characterization of Baths

Liquid baths are the main calibration equipment to directly affect the measurement uncertainty in temperature calibrations. Therefore, the characteristics of baths need to be well investigated and understood. The temperature profile and stability of liquid baths are one of the most important contributions to the calibration uncertainty of platinum resistance thermometers, digital thermometers, liquid-in-glass thermometers, and thermocouples. Commercial baths only present stability and uniformity data in two dimensions in general; however, thermometers and thermocouples are immersed into the body of the bath, so the depth or z-axis is also very important. In this study, a measurement system has been designed using three-stepper motors and a data acquisition system (DAS). The DAS is developed using object-oriented algorithms to form a three-dimensional (3-D) scanning system. The 3-D scanning system is home-made and used in conjunction with a reference platinum thermometer. The temperature profiles and stability of several types of baths: water, oil, and salt were obtained in the temperature range from 30???C to 450???C. Therefore, this contributed toward a more accurate uncertainty budget evaluation.     

A CFD Study on a Calibration System for Contact Temperature Probes

Surface-temperature measurements by means of contact probes require a detailed investigation of the probe-surface interaction. For an accurate calibration of such probes, the heat transfer processes involved in contact measurements must be well known and the impact of any influence parameters must be taken into account. At present, contact probes are generally calibrated by means of a temperature-controlled hot plate. A calibration system for contact surface-temperature probes, based on such a hot plate, was developed at INRIM. It covers the temperature range from ambient to 350 °C. The reference temperature is available on the upper surface of a metal block and is determined by linear extrapolation of the readings of three calibrated thermometers embedded into the block at different depths. However, the actual temperature of the reference surface largely depends on the sensor-to-surface interaction. The contact thermal resistance, the thermal conductivity of the block, the geometry of the probe, and the temperature of the surrounding fluid are just some of the parameters that affect a calibration and that may cause measurement errors if they are not properly taken into account and corrected for. Better insight into the interaction between the surface and the probe is therefore required. Since the experimental evaluation of measurement errors is not straightforward, mathematical modeling could represent a crucial tool to better understand the interactions between the probe and the calibration system. In this paper, a finite-element numerical model of the INRIM calibration system was developed in order to investigate the temperature field across the reference block as well as on its surface during a calibration. The thermal load introduced by a commercial contact probe during a calibration was also included in the simulation and its effect on the temperature field was studied. In order to obtain a detailed mathematical model, the surrounding air was also included in the simulation, avoiding the imposition of boundary conditions at the interface between solid parts and fluid. The proposed model was validated by comparing the results obtained with the available experimental data.     

Investigation on 50 �� Rhodium�CIron Sensors with Ceramic Shell

Rhodium?Ciron sensors with a ceramic shell and 0.03 mm diameter wires drawn from 0.05 mm diameter wires have been investigated. Results indicate that a proper annealing process is required for the drawn wires to be used in the sensor. The stability of the 30 thermometers made in this way were investigated after being exposed to 20 thermal cycles between 4.2K and room temperature. The thermometers remained stable at 273.15K within 10mK. A standard reference curve was obtained by 58 calibration points from 1.2K to 300K for ten thermometers. With this curve, the R?CT relationship was fitted for the other sensors in the same batch within 0.1K accuracy with just a few temperature points. Finally, the self-heating effect was discussed. The results indicated that the performance of the thermometers with drawn wires are the same as that of the thermometers with the original 0.03 mm diameter wires.     

Evaluation of a Portable Apparatus for the Realization of the Triple Point of Argon

In this paper, the evaluation of the performance of a portable triple-point-of-argon apparatus, via the analysis of the calibration history of selected working (fused silica) standard platinum resistance thermometers (SPRTs), is presented. These have an extensive calibration history, both internally (using different apparatus) and externally at two National Measurement Institutes. A special procedure had to be developed, for the calibration of metal-sheathed SPRTs, in order to ensure adequate thermal contact between the SPRT and the well and to minimize the influence of stem conduction, inherent in the compact design of the maintenance system. The results show good agreement between the measurements performed with this system and those with the previously used apparatus, to a level of uncertainty consistent with the INTA calibration and measurement capability (CMC) of 3.0 mK (k = 2). This CMC is given by the Spanish accreditation body (ENAC), under accreditation No. 16/10.007, for the routine calibration of SPRTs at the triple point of argon. It is concluded that the portable apparatus is suitable for use as a transfer standard for the comparison of local realizations of the triple point of argon. This avoids the need to shipping fragile SPRTs, with a valuable long calibration history, and eliminates the contributions due the long-term stability of the thermometers subjected to transportation. The long-term stability of the portable apparatus reported in this work has only been determined in laboratory conditions.     

提高辐射温度计检定结果准确度的方法研究

现行的辐射温度计检定规程,概念不够清晰,具体操作步骤描述过于简单,造成检定的实际测量条件有明显的差异,由此导致检定结果的差异。本文从技术角度出发,提出了一种可行的操作方法,力图提高辐射温度计检定结果的准确度。     

Operation of the TVO temperature sensors in the range from 4.2 K up to 425 K

The report continues our investigations on cryogenic thermometers. To estimate the influence of warming the well known TVO temperature sensors [Proceedings of the ICEC17 (1998) 699, Cryogenics 41 (2001) 213, Advances in Cryogenic Engineering 45B (2000) 1817, Proceedings of the ICEC18 (2000) 627] up to 425 K on their calibration curve, a series of experiments have been carried out. The number of thermal cycles in the range from 425 K down to 77.3 K was 105. Comparison of readings of the sensors at 293, 77.3 and 4.2 K was performed with initial calibration curves for 100 cycles. Then several sensors were re-calibrated, and a new comparison was done during five additional thermal cycles at the same temperatures. The obtained results are discussed and they seem to be optimistic.     

The Immersion Characteristics of Industrial PRTs

Immersion effects are one of the most significant sources of error in the use of industrial platinum resistance thermometers (IPRTs). This article combines the development of a mathematical model of immersion error and experimental measurements of the immersion characteristics of a range of IPRTs immersed in different fluids at different temperatures. The mathematical model relates the relative temperature error in the thermometer indication to two exponential terms, with one of the 1/e decay lengths three times the other. The experimental results show that both of the exponential terms are important for shallow immersion, but one is sufficient for long immersion. The decay length for the thermometers depends on the diameter of the probe and on the thermal environment into which it is immersed. For the thermometers evaluated here in mineral oil, silicon oil, and molten salt, the 1/e decay length is about three to four times the diameter of the thermometers. A simple rule of thumb for ensuring adequate immersion in calibration baths is developed.