马弗炉烘炉升温曲线的研究

<正> 本文根据硅砖和粘土砖的线膨胀曲线,联系本厂多年来烘炉的实践.提出了一条可减小炉体内部的热应力、保持炉体结构的整体性和气密性的烘炉升温曲线。1.前言钢丝热处理马弗炉(以后简称炉子)是中、高碳钢丝和钢丝绳生产厂家的主要热处理设备。新建或者经过大修的炉子,一定要先按照规定的烘炉升温曲线进行     

变压器引线线夹焊缝开裂缺陷的检测与成因分析

文章对特高压变电站变压器引线线夹焊缝熔合线处开裂事故进行了原因分析,对焊缝缺陷开展了现场渗透无损检测,明确了缺陷的大小和位置,对线夹取样解剖分析,发现焊缝内部结构存在着严重的未焊透及未熔合现象,严重影响了焊缝结构强度。进一步分析了焊缝缺陷成因,对提高产品质量和加强检测监督提出了意见建议。     

一起炉膛水冷壁爆管事故的原因分析及预防

通过对一起高压蒸汽燃气锅炉试运行阶段炉膛水冷壁爆管事故的原因分析,阐明了珠光体的高温球化现象对金属强度的影响,指出按章操作的重要性和必要性,正确的烘炉操作是避免发生烘炉阶段爆管事故的关键。     

焊缝宽度对碳钢对接接头残余应力分布的影响

针对当前大量焊接结构采用对接接头形式,存在焊缝宽度影响结构表面残余应力分布的问题,课题组结合有限元仿真软件ABAQUS建立了一种利用双椭球摆动热源进行窄间隙焊接的平板对接模型,并使用焊缝非线性的热弹塑性有限元法,计算出Q235 A钢在4种不同焊缝宽度下对接焊接接头的残余应力分布.计算结果表明:小尺寸焊缝宽度的对接接头在...     

馒头比面包更富与营养

用普通烘炉烤出来的面包,有一层金黄色的表皮,吃起来会比馒头可口得多.然而这种烘烤方法使面粉中的赖氨酸在烘炉的高温作用下发生分解,产生棕色的物质.而用蒸汽蒸出的馒头,则无此反应,因而蛋白质的含量会显著高些.以微波烘炉代替普通烤炉烤制的面包,也可避免赖氨酸遭受破坏.所以从营养价值来看,吃蒸馒头要比吃普通烤炉烘制的面包好些.     

基于角焊缝缺口系数数据库建立及应用

文章结合Neuber提出的虚拟缺口半径理论,利用Radaj焊接结构的缺口应力疲劳分析方法,针对某公司30%焊透率的T型焊缝建立了满足自身要求的焊缝缺口应力集中系数数据库。通过路试采集的道路谱进行整车多体动力学载荷分解,得到焊缝疲劳分析的拖曳臂硬点载荷输入,并结合疲劳分析软件Femfat为焊缝的评估提供了一套有效的分析方法。结果表明,新建的焊缝数据库有效的预测了焊缝失效,并在路试中得到了验证,为项目开发的前期产品改进提供理论依据,能够有效节约开发成本,缩短开发周期。     

模糊控制技术在饼干烘炉中的运用

国外饼干企业现大都采用煤气炉 ,煤气炉具有超调小 ,滞后性小 ,灵敏度高的控制优势。针对我国饼干生产技术落后的不利局面 ,现就关键部位(电热管烘炉)进行改进 ,以弥补与煤气炉设备差距的不足。现采用模糊控制技术来优化温控系统的结构。解决了滞后超调现象 ,又节约了能源     

浅谈焊工操作的一些技巧

焊缝质量直接影响焊接结构的使用性能与安全性,焊缝的质量直接体现焊工的技术水平。一名优秀焊工如何才能学得快,掌握得牢,需要掌握一些技巧,重点介绍了一些焊接操作技巧。     

浅谈钛,钛合金复合钢板焊缝质量控制

本文论述了钛及钦合金复合钢板制造大型蒸发设备中,复合板焊缝结构选择,焊缝坡口设计,加工、基层焊接过程的钛保护,以及钛复合层焊接质量控制等影响设备制作成败的关键技术问题。     

制罐中涂料固化的监控

<正> 对于生产两片罐和三片罐的厂家来说,上涂和涂料固化过程是生产的关键,而烘炉温度的准确监控是优化固化效果的重点工艺。在制罐工业中,许多生产厂家正采用一种称为DATAPAQ系列炉温追踪仪来临控烘炉温度,在保证产品质量的同时,优化产量。 涂料固化的重要性 在IBO烘炉中,正确的涂料固化相当重要。倘若固化不足,便会使所盛装的产品(啤酒、可乐、软饮料)与罐体的金属物质发生反应而导致渗漏,同时影响饮料的味道。另一方面,过度固化则会使涂料出现收缩现象,同样引起相同的问题。     

烟酰胺水分测定方法的筛选

为确定一种误差小、精密度高且能测定烟酰胺产品水分含量的方法,比较卡尔费体容量滴定法、不带鼓风电热恒温干燥箱法、带鼓风电热恒温干燥箱法与硅胶为干燥剂干燥器法测定酰胺产品失水率的差异.结果表明:使用不带鼓风和带鼓风电热恒温干燥箱的检测结果分别比容量滴定法高出0.295%～0.5%和0.365%～1.12%;使用带鼓风的比不带鼓风的电热恒温干燥箱检测结果高出0.10%～0.62%;而硅胶为干燥剂的干燥器法测定的结果低于产品实际含水量.综合而言,卡尔费休容量滴定法的重复操作性强,结果准确,测定烟酰胺产品水分含量可优选卡尔费休容量滴定法.     

Effect of Cooking Rates in Electric or Microwave Oven on Cooking Losses and Retention of Thiamin in Broilers

A study was conducted to determine the effect of two microwave oven and two electric oven cooking rates on retention of thiamin and cooking losses with broiler chickens. Thiamin was determined by a microbiological turbidimetric assay of raw and cooked meats. Broilers cooked in the microwave oven retained more thiamin than broilers cooked in the electric oven. There was no difference in thiamin retention between broilers cooked in the microwave oven at 800 and 1600 watts. Broilers cooked in the electric oven at 204°C retained more thiamin than broilers cooked at 121°C. Broilers cooked in a 1600 watt microwave oven had the greatest weight loss. No difference in weight loss occurred between broilers cooked in an 800 watt, 121°C or 204°C oven.     

A Reasearch Note VITAMIN B6 IN PORK MUSCLE COOKED IN MICROWAVE AND CONVENTIONAL OVENS

Loin sections of pork muscle were heated to 75 or 85°C internal temperatures in microwave or conventional electric ovens. Cooking losses and time, percentage moisture and total vitamin B₆ were determined. Cooking time was longer, total cooking loss less and moisture content greater for pork cooked in an electric oven than for that cooked in a microwave oven. Differences in vitamin B₆ due to type of oven or internal temperature were small and not significant when calculated on a cooked weight basis. When calculated on a dry weight basis samples cooked in the conventional oven contained more vitamin B₆ than did those cooked by a microwave oven.     

Effect of different baking modes on the physico-chemical and sensory characteristics of tandoori roti

Studies were carried out to determine the effect of baking, in different types of oven such as an earthen tendoor, a gas tandoor, an electric oven and a heated plate, on the physico-chemical and quality characteristics of tandoori roti. The studies indicated that the extent of gelatinization of starch varied depending on the type of oven used and was found to be 74.6, 78.4, 90.7 and 88.4% in roties baked in an earthen tandoor, a gas tandoor, an electric oven and a heated plate respectively. The pasting characteristics of starch, separated from the tandoori roti sample and measured using a Rapid Visco Analyzer, indicated the highest peak viscosity (36 SNU) for tandoori roti baked in an earthen tandoor and the lowest (25 SNU) for that baked in an electric oven. The concentration of high molecular weight proteins was lower in roti baked in an earthen tandoor and a gas tandoor, indicating greater dissociation of high molecular weight proteins during baking in such ovens. The sensory texture, taste and flavour of roti baked in an earthern tandoor was found to be superior to those baked in other types of ovens.     

不同制油方法对青海亚麻籽油品质及货架期的影响

为研究不同制油方法对青海亚麻籽油品质及货架期的影响,对青海亚麻籽分别进行焙炒、烘烤、高压高温湿热、脱胶、真空冷冻干燥前处理,再分别采用螺旋压榨法和液态静压法制油,测定亚麻籽油出油率、过氧化值、酸价、水分及挥发物质量分数、脂肪酸含量、挥发性组分相对含量、总酚含量,并利用Schaal烘箱法建立亚麻籽油氧化动力学模型预测货架期。结果表明,焙炒螺旋压榨法制得的亚麻籽油出油率、总酚含量明显高于其他处理组,过氧化值、酸价、水分及挥发物质量分数均低于其他处理组,模拟预测货架期最长,为353 d。焙炒螺旋压榨法制得的亚麻籽油挥发性组分种类最多,为72 种,其他制油方法制得的亚麻籽油挥发性组分为40～60 种,不同制油方法对亚麻籽油挥发性组分影响明显。此外,亚麻籽油5 种主要脂肪酸中亚麻酸含量最高,为54.71～61.03 g/100 g,不同制油方法对亚麻籽油脂肪酸含量影响不明显。综上,与其他方法相比,焙炒螺旋压榨法制得的亚麻籽油品质较好。     

网带式热风循环电热比萨炉的设计和研制

重点阐述了网带式热风循环电热比萨炉的工作原理和烘烤过程、结构设计和控制系统设计,以及对差异性结构设计的可行性分析;并通过研发试产后,提出功能扩展的设想,探讨遂道式万能蒸烤炉的初步设计方案,可以通过增加蒸气加湿功能来扩大比萨炉的适用范围。     

Evaluation of baking performance by means of mid-infrared imaging

The present work aims to validate mid-infrared imaging as a promising method for evaluating oven systems. Therefore, a novel approach by analyzing mid-infrared radiation patterns captured by a thermal camera and subsequent image processing was developed. A thermal camera was adapted to two different oven systems: a standard electric deck oven and a novel gas-fired baking oven with integrated volumetric ceramic burners (VCBs). The baked goods were analyzed and key indicators describing the final product quality were determined. Specific volume, surface browning and mid-infrared image processing demonstrated a comparable performance of both oven systems. Furthermore, the determined surface heat homogeneity of the items to be baked was 0.65 ± 0.05 (–) for the electronic oven and 0.70 ± 0.03 (–) for the VCB oven. The proposed approach proved its fundamental qualification for comparing and evaluating different oven systems.     

Effect of cooking on the formation of N-nitrosodimethylamine in Korean dried seafood products

Only N-nitrosodimethylamine (NDMA) was detected when N-nitrosamines (NA) were analysed in seven dried seafood products, either uncooked or cooked. The cooking methods used were a briquet fire, a gas range, an electric oven, a microwave oven, a steam cooker and an electric coil cooker. The contents of NDMA ranged from 1.0 to 46.9 μg kg^-1 in uncooked products. When these samples were cooked, regardless of the cooking method, the content of NDMA tended to increase, ranging from 1.1 to 630.5 μg kg^-1. In general, indirect heating such as a steam cooker and a microwave oven, as compared with direct heating such as a gas range and a briquet fire, caused less increase in NDMA during cooking.     

微波紫外线协同生物学作用及紫外线微波炉杀菌研究

在微波紫外协同生物学效应研究的基础上,采用一种特殊的控制电路使微波与紫外线结合起来,制成微波紫外线微波炉,它兼容微波良好的穿透性和紫外线的强灭菌性。微生物学检验表明微波和紫外线协同杀菌作用明显优于单独微波杀菌或紫外线杀菌作用。