印刷机常用干燥技术(2)

2.挥发干燥 印刷油墨包含许多成分,如树脂、颜料和溶剂等,部分干燥过程是通过挥发来完成,一般会发生从液态(溶剂)到气态的转变,生成蒸气排出.通常情况下,加热温度越高,排出的蒸气越多.但对于加热温度不能太高的承印物,如果加热温度过高,就会出现套印不准,承印物黏弹性发生变化以及翘曲等现象.当印刷油墨经过挥发式干燥装置时溶剂挥发,这个干燥过程取决于液体(油墨)表层的热量、材料和传递.     

浸渍干燥生产线概述(续)

正2.3涂胶机经第一段干燥后,可进行第二次涂胶。涂胶机主要有3种不同的涂胶方式。第一种是传统的涂胶方式,涂胶机由上下涂胶辊及匕下扫平辊组成(见图4)。上下涂胶辊、上下扫平辊均由单独电机驱动,变频调速,涂胶量的多少可通过涂胶辊网纹的目数及涂胶辊的转数进行调节。涂胶辊的转数调节量比较小,如果涂胶量变化大应     

印刷机常用干燥技术(1)

干燥过程包括油墨转移后的所有过程,在这些过程中,油墨固化是印后加工的首要条件,也是印刷品在日常生活中得以使用的前提.     

实用木材干燥手册(上)

前言本书是一本叙述木材干燥知识的一本手册,主要收集和总结的内容有木材干燥有关的技术术语及常用树种的干燥工艺;实用记录表格与新编的相对湿度及平衡含水率表。本手册采用实用、通俗易懂的方式编写。可供木材工业方面搞木材干燥的技术人员及操作者选用参考。     

食品干燥技术之一——泡司(PELLET)的干燥

介绍了食品干燥中常用的方法 ,泡司的热风干燥过程、干燥器具及参数的控制。     

食品干燥技术之一——泡司(PELLET)的干燥

介绍了食品干燥中常用的方法 ,泡司的热风干燥过程、干燥器具及参数的控制。      

Foam-mat drying of starfruit (Averrhoa carambola L.) purée. Stability and air drying characteristics

Foams were prepared from starfruit (Averrhoa carambola L.) purée by adding various concentrations of methocel. Overrun and density of the foams from various concentrations of methocel were compared. Relative stability of the foam was determined by comparing amounts of juice separated from foam at 70°C. Drying rates at two drying temperatures (70 and 90°C) were also compared. Quality of the dry and reconstituted powder was evaluated with simple sensory evaluation and Hunterlab instrument. Overrun and stability of foams increased with increasing methocel concentration until maximum value was obtained at a methocel concentration of 0.4% w/w. Falling rate was observed for foam dried at both temperatures. Drying time could be shortened by as much as 30 min when drying temperature was increased from 70 to 90°C. However, obvious colour and flavour changes were observed in the product dried at 90°C. This study has indicated that, under the experimental conditions employed, reasonably good powder characteristics can be obtained.     

方便米粉快速干燥生产新工艺研究报告(一)

报道了以快速干燥与风力松丝为核心的方便米粉生产新工艺,包括单机熟化与食品添加剂使用技术。采用此工艺生产的方便米粉,能抑制淀粉返生,复水性达到了方便面同样的水平。     

果蔬微波真空干燥(MVD)技术研究进展

文中综述了MVD(microwave-vacuum drying,微波真空干燥)技术及其在果蔬加工中的应用情况,从MVD对果蔬品质的影响,果蔬MVD工艺优化,果蔬MVD特性研究,果蔬MVD动力学研究,MVD与其他干燥方法对果蔬干燥效果的对比,MVD联合其他干燥技术加工果蔬等方面概述了果蔬MVD技术的研究现状,分析了该技术在实际应用中存在的一些问题,展望了其在果蔬加工中的发展前景。     

纸张干燥技术及其能效分析(上)

纸机的干燥部是造纸厂热能消耗的最主要部分,也是节能减排工作的重点,不同的干燥方式,能源的利用效率各不相同,能源成本也存在较大差异。本文介绍了蒸汽烘缸干燥及气罩系统以及常用于涂布纸的红外干燥、热风干燥的基本原理、能源利用效率及使用成本等,并定量计算进行了说明。从辐射的原理入手,详细解释电红外与燃气红外的异同,澄清人们对这两种红外干燥器能源利用效率的误解,文中的计算结果也为干燥系统的选用或优化提供了数据支持。     

影响印铁油墨干燥因素分析(上)

油墨的干燥过程是油墨从流体状态转化为固体状态的过程.在铁皮印刷过程中,油墨转移到承印铁皮上之后,再经过干燥系统进行干燥,最终转化为固态,再现印刷原稿图文,从而实现整个印刷过程的最终目的.     

中密度纤维板生产的纤维干燥(续)

5 影响纤维干燥质量的因素 纤维干燥质量主要取决于下列因素:干燥管道内热介质的温度、纤维的输送浓度、管道内气流流速和纤维质量好坏等.因此,在中/高密度纤维板生产中须根据上述因素对干燥工艺进行调整,以获得最佳的干燥效果. 5.1 干燥介质温度 干燥介质温度的高低不仅影响干燥时间的长短,而且直接关系到干燥后纤维的质量。采用较高的温度既能使干燥时间缩短,又能减少干燥管道的长度和降低动力的消耗.但对于采用先施胶后干燥工艺,并且是施加脲醛树脂胶的情况下,一定要防止在高温条件下纤维上的胶粘剂提前固化及纤维炭化,从而影响产品的质量;若采用低温介质,虽可避免施胶纤维的胶粘剂提前固化和纤维炭化,但需要的干燥时间过长,生产效率降低. 中密度纤维板之5     

影响印铁油墨干燥因素分析(下)

润版液的影响 在胶印工艺中,润版液的作用非常重要,它直接影响到印刷过程能否顺利进行.润版液对油墨干燥性能的影响通常有以下两个方面. 1.润版液pH值的影响 通常润版液的组成成分中含有酸性物质和盐类物质,如磷酸、乙醇以及其他无机盐,因此润版液整体呈现酸性.     

方便米粉快速干燥生产新工艺研究报告(二)

５问题与讨论５１方便米粉不能等同于细丝米粉我国方便米粉的研制,始于８０年代的波纹型方便米粉［１］。波纹米粉是仿照波纹方便面的生产原理与工艺而研制的,无老化处理,可实现生产的机械化与连续化,α化程度高,从本质上讲,是真正意义上的方便米粉。但是,波纹米...     

Batch drying of banana pieces — effect of stepwise change in drying air temperature on drying kinetics and product colour

Slices of banana were dried in a two-stage heat pump dryer capable of producing stepwise control of the inlet drying air temperature while keeping absolute humidity constant. Two stepwise air temperature profiles were tested. The incremental temperature step change in temperature of the drying air about the mean air temperature of 30°C was 5°C. The total drying time for each temperature-time profile was 240 min. The drying kinetics and temporal colour change of the products dried under these stepwise variation of the inlet air temperature were measured and compared with constant air temperature drying. The effects of the profile starting temperature and cycle time on both drying kinetics and product quality were also studied. It was observed that by employing stepwise-varying drying air temperature with appropriate starting temperature and cycle time, it was possible to reduce significantly the drying time to reach the desired moisture content with improved product colour.     

浅谈催干剂对印刷品干燥的影响(续)

环境湿度对印迹干燥亦有影响,相对湿度大,空气中水分增多,氧的活动受到较大的阻碍,使油分子对氧的吸收将受到影响,另外,在吸收氧时,由于空气中的水分子增多,或多或少地要吸收部分水分子,水分子在油墨中起阻氧作用。所以相对温度大,油墨干燥速度慢,相对湿度小,油墨干燥速度快。一般来讲,在相同条件下,相对湿度升高10％,则干燥时间会延长一倍左右。因此控制好车间的温湿度很有必     

砌体结构墙体对梁(板)的约束

在梁板支承长度不大,梁板跨度较小时,由铰接计算简图引起的误差很小,使计算得到了简化,但在梁板支承长度较大,梁板跨度较大时,梁端约束力矩也明显增大,这样,有可能使墙体产生不可忽视的嵌固弯矩,严重影响墙体的承载能力,使墙体的设计偏于不安全。     

Effect of temperature on antioxidant capacity during drying process of mortiño (Vaccinium meridionale Swartz)

The mortiño fruit (Vaccinium meridionale Swartz) has been recognized as an excellent source of antioxidants, phenolic compounds, and anthocyanins. Drying conditions, particularly temperature, often lead to food quality degradation. The present study investigated the influence of drying temperature (40, 50, and 60°C) on antioxidant activity, anthocyanin, and phenol content of mortiño. Four different thin layer drying models of drying kinetics (Modified page, Newton, Henderson & Pabis and, two-terms) were fitted to the experimental data. For antioxidant capacity determination, oxygen radical absorbance capacity and ferric ion reducing antioxidant power assays were used. The results showed that antioxidant capacity, and phenolic and anthocyanin content all decreased with increasing temperature and drying time. It was observed that phenols and anthocyanins were conserved in greater amounts at 60°C with 34% (5.85 mg gallic acid/g dm) and 32% (2.36 mg Cyanidin-3-glucoside/g dm) preservation of initial content, respectively. Drying kinetics models were compared based on their R² and root mean square error values between the experimental and predicted moisture ratios. The two-terms model was found to satisfactorily describe the drying curves for all temperatures evaluated, with a determination coefficient (R²) above 0.9987 and root mean square error lower than 0.0201.     

新型振动逆流式冷却(干燥)机的研究开发

介绍了一种新型振动逆流式冷却(干燥)机的设计方法及其结构和工作原理,论述了该机的主要优点,表明了它在机器结构、冷却效果、冷却物质量及工作噪声等诸多方面均优于现有的逆流式冷却机,为冷却机的更新换代创造了条件。