石横特钢自制热电偶测温误差分析

石横特钢为降低生产成本,自制快速测温热电偶。分析了引起自制热电偶测温误差的因素,并相应提出了提高测温准确度的措施。应用表明,自制热电偶测温准确率达到了98%以上,满足了炼钢生产工艺要求,节约了成本。     

基于热电阻的DCS中温度保护逻辑设计

本文提出一种DCS中的温度保护逻辑设计方法,用以克服因测温元件热电阻在断线时存在延时,端子接触不良等因素所引起误保护动作的发生。此方法不但能在最大限度地保护生产装置和人身安全的同时;也能最大限度地避免误保护动作的发生,尽可能地减少非正常状况下的误停车。     

热电偶测温误差分析

针对工业加热炉，详细分析了热电偶测温过程，由于热电偶热端与炉墙内表面之间的辐射换热，以及热电偶本身因热端和冷端温度不同造成的导热总是存在，因此热电偶测温存在误差。本文从理论上分析了热电偶测温误差的来源，提出了热电偶测温误差计算模型，并导出了测温误差的近似计算公式，还结合实例讨论了减小测温误差的措施。     

表面测温技术在焦油蒸馏中的应用

通过探讨表面测温的工作原理和测温元件的安装方法,介绍了非接触式表面测温方法,在精度上和稳定性上均满足了生产要求,具有较好的推广价值。     

澳斯麦特炉烟气温度检测技术的改进

针对澳斯麦特炉上升烟道烟气温度检测时接触式温度检测元件易损的问题,改进测温方式,采用二氧化碳红外气体测温。文中介绍了二氧化碳红外气体测温的原理、使用条件,通过对比阐述了二氧化碳红外气体测温方式的优越性,为同类型冶炼炉烟气温度检测中存在的共性问题提供了一种解决方案。     

焦炉炉顶自动测温技术应用及探讨

介绍了焦炉测温的几种方法，对比分析了几种测温方式的误差，阐述了红外线测温的原理和目前自动测温的缺陷，提出今后实现焦炉自动测温的发展方向及思路。     

热风炉顶红外线测温装置的技术改造

宣钢炼铁厂热风炉顶测温,过去一直使用贵金属铂铑——铂热电偶作为测温元件。近年来,高炉操作要求高风温,热风炉顶热电偶因温度过高常被烧坏,耗量大,维修费用多,因此我们采用了红外线测温。红外线测温反映快、灵敏度高,使用寿命长,经济效益明显。但测温光路易受灰尘,水汽影响,轻者影响精度,严重时根本不能使用。我们经过几年来的试验研     

交流同步电机测温

一、问题提出电机在运行中,机体内部进行着能量转换过程。在转换过程中,其中一部分能量没有被有效地利用,而被损耗掉了。这种损耗,最后将转换成热能,使电机各部发热,温度升高。因此,测定电机在运行中的温度,具有重要的意义。当前测定电机温度的方法一般有电阻法、温度计法和埋置测温元件法等三种。电阻法仅能测定其中某些部件的温度,如直流电机的激磁绕组,同步电机的激磁绕组等;温度计法也有它的局限性;埋置测温元件法虽给维护人员在运行中监视电机运行温度提供很大方便,但这些测温元件是在电机制造     

温控自动报警器的制作

冶金企业中,运转机械及电器的温升控制是保证设备正常与安全运行的一个重要因素。因此,我们制作了一种温控自动报警器,其外形及原理图见图1和图2。测温元件选用电接点玻璃水银温度计。因为它的物理性能稳定,体积小,误差小(0.2—3℃),温度指示直观,不怕强电磁场干扰。如果所需温升控制是定值的,可选用固定式单接点玻璃水银温度     

热电偶在焙烧炉中异常问题的分析及处理

在焙烧炉工艺应用中的测温元件存在温度变送器经常烧坏和热电偶输出线产生电火花打手现象。为消除给生产和安全带来的影响,通过对热电偶、温度变送器本身及测量回路、接地方式的逐一分析,发现热电偶产生大量的静电是引起异常的真正原因,并根据这种情况提出了解决问题的方法。     

Study on Error Compensation Method of Online Roll Profile Measurement

Flatness and surface quality are important quality indexes of strip steel, and roll wear will directly affect the product's flatness and surface quality. Online roll profile measurement technology can obtain the information of roll profile in real time, guide the optimization of roll change rhythm, and improve the flatness control ability of rolling mill and surface quality of strip product. However, the error caused by roll displacement, clearance, roll thermal crown, and other factors is usually the same order of magnitude as the roll shape or roll wear, or even one order of magnitude higher. So error compensation is the key to ensuring the accuracy of online roll profile measurement. Herein, the position measurement technology of the roll bearing block is considered in the online roll profile measurement, and the measurement error caused by the deviation of the roll axis is separated. The thermal crown model is established to separate the measurement errors caused by the thermal crown. The error compensation model of online roll profile measurement is established, and the simulation calculation is carried out. This error compensation method is of great significance to improve the accuracy of online roll profile measurement and realize the fine management of mill roll in service.     

Study on strip running deviation at exit of heat section in continuous annealing furnace for cold rolling

In order to solve strip reciprocating and quick- moving running deviation at the exit of heat section for vertical continuous annealing furnace, the thermal crown of furnace roller was analyzed quantitatively and regression method was used to determine the impact of roller crown on strip running deviation. And then the alarm program for strip running deviation was established, which can give early warning of strip running deviation and adjust the model parameter and the heating and cooling temperature rate simultaneously. With the application of this system on a continuous annealing machine for cold rolling in Shougang Jingtang Company, the strip running deviation which caused by thermal crown of furnace roller can be solved.     

4.3 K～299 K温区Cu-ETP热膨胀系数原位实验测量研究

采用多模式微波谐振法,开展了定压气体折射率基准测温系统中谐振腔材料电解精炼韧铜(Cu-ETP)线性热膨胀系数的高精度原位实验测量及其不确定度分析研究,温度范围为4.3～299 K.针对不同的温度区间,采用了降温法(5～299 K)和控温法(4.3～26 K)两种实验测量方案,通过降温法测得的线性热膨胀系数标准不确定度优于2.2×10^-7 K^-1,其中,重复性是其测量不确定度的主要来源;通过控温法测得的线性热膨胀系数标准不确定度优于2.9×10-9 K^-1,微波模式一致性和重复性是其测量不确定度的两大主要来源.由于控温稳定性高、微波测量噪声低,控温法所获得的线性热膨胀系数结果更为精确.最后,按照温区范围进一步发展了该系统内Cu-ETP材料线性热膨胀系数的计算方程,实现了实验数据与温度的高精度关联.     

热连轧工作辊热平衡的优化研究与应用

轧辊热膨胀对承载辊缝形状和带钢板形具有显著的影响,而准确预报轧制过程中轧辊热膨胀是板形控制中的难点之一。针对某热连轧生产线单辊期内热膨胀量与轧辊温度不收敛的问题,利用自主开发的与产线生产完全一致的板形模型分析测试系统对热凸度二级模型进行了仿真分析与研究,提出了一种有效提高工作辊热平衡收敛性的优化方法,并进行了生产应用。该优化方法的应用解决了该热轧产线单辊期内热平衡不收敛的问题,消除了轧辊温度计算值和实测值之间的偏差,不仅提高了模型的预报精度,也大幅提高了该产线轧制带钢的凸度控制精度。     

岩温对曹家洼金矿深部开采热环境的影响

曹家洼金矿小尹格庄矿段已进入深部开采,岩温是影响采场热环境的主要热源;根据热传导理论分析,采用浅孔测量岩温的方法合理可行,通过测量得出了曹家洼金矿岩温随深度变化的规律;在此基础上,计算分析了岩温对井下风流温度升高的作用,认为该矿深部开采存在一定程度的热害,热环境有进一步恶化的趋势,需加强通风降温措施,切实改善井下作业环境。     

模糊控制策略对焊接热模拟温度控制的优化

 基于焊接热模拟温度控制系统具有高响应、纯滞后、试验条件变化时系统参数时变,特别是加热速率高、调整时间短的特点,常规的PID控制很难满足温度控制的精度要求。自主研发了焊接热模拟计算机软件,并采用模糊自适应PID控制策略,应用模糊集合理论,根据不同的偏差和偏差变化率在线自整定参数Kp、Ki、Kd,实现了PID参数的自动调整,精准地完成焊接热模拟试验的温度控制。     

A Compensation Model of Continuous Temperature Measurement for Molten Steel in Tundish

 A compensation model has been proposed to reduce errors caused by the immersion depth of the sensor and the time lag of continuous temperature measurement for molten steel in tundish, which is based on the limited data fitting method and data fusion technology. According to the heat transfer analysis of sensor, the thermal model has been bulit to determine the temperature variation function.The parameters of the compensation model are recognized by generic algorithm, which combines the determine function, the molten steel mass in the ladle and pouring time. The processing of error compensation is divided into three stages: tracking, holding and compensation. When the processing is stable, the measured temperature error is small, and the measured temperature is regarded as accurate value and tracked. For the end of pouring stage of the ladle, the temperature error is caused by the immersion depth of the sensor, and the measured temperature before sharp decreasing is considered as real temperature and held. For the temperature increasing stage after ladle changed, the measured temperature is compensated online.The application results show that the error between the compensation temperatures and the actual ones have been decreased to ±2 ℃, and the time lag could be shortened from 3-5 min to 40 s by applying this model.     

基于红外CCD热成像测温的加热炉钢坯温度场模型研究

将红外CCD热成像测温技术应用到加热炉钢坯表面温度测量,以直接测得的表面温度作为建立钢坯模型的边界条件,并以传热学为基础,建立了加热炉钢坯温度场模型。同时,应用现场数据对模型进行了验证,结果表明:该方法进一步提高了现行温度场模型测量精度,完全符合工业应用的要求。     

Effects of Recovery Behavior and Strain-Rate Dependence of Stress–Strain Curve on Prediction Accuracy of Thermal Stress Analysis During Casting

Recovery behavior (recovery) and strain-rate dependence of the stress–strain curve (strain-rate dependence) are incorporated into constitutive equations of alloys to predict residual stress and thermal stress during casting. Nevertheless, few studies have systematically investigated the effects of these metallurgical phenomena on the prediction accuracy of thermal stress in a casting. This study compares the thermal stress analysis results with in situ thermal stress measurement results of an Al-Si-Cu specimen during casting. The results underscore the importance for the alloy constitutive equation of incorporating strain-rate dependence to predict thermal stress that develops at high temperatures where the alloy shows strong strain-rate dependence of the stress–strain curve. However, the prediction accuracy of the thermal stress developed at low temperatures did not improve by considering the strain-rate dependence. Incorporating recovery into the constitutive equation improved the accuracy of the simulated thermal stress at low temperatures. Results of comparison implied that the constitutive equation should include strain-rate dependence to simulate defects that develop from thermal stress at high temperatures, such as hot tearing and hot cracking. Recovery should be incorporated into the alloy constitutive equation to predict the casting residual stress and deformation caused by the thermal stress developed mainly in the low temperature range.

     

80W大功率LED路灯的散热特性研究

结温与热阻是大功率LED路灯的热特性的重要指标,温度对LED的性能产生严重的影响。基于正向电压法原理,建立了LED结温、热阻的测试装置,分析拟合了某公司80 W LED路灯的温度系数K,并对其结温和热阻进行了测量,分析了翅片温度分布及散热特性。研究结果为大功率LED路灯结构设计提供了重要参考。