调浆开停自动装置

上海第廿八织布厂是专织工业用砂皮布的。根据上海砂轮厂的工艺要求,浆纱工艺必须用淀粉上浆。才能保证铁砂皮的使用质量。但该厂调浆设备的调浆叶轮是装在电机轴上的,转速快,适用于化学上浆。而淀粉浆液不宜搅拌过快,尤其是浆料煮熟后,更不宜高速搅拌。因搅拌过头,将造成浆液粘度差,质量低;如搅拌不足,浆液会沉淀,浓度低,这样都会影响浆纱质量和棉布质量。这就要求调浆操作工在浆熟后,必须掌握搅拌时间,用开开停停的方式进行,以保证浆料质量。但由于厂小,人员紧张,调浆工要兼做其他工作,不易掌握搅拌时问,浆液质量因此很难保证。该厂电工自已动手搞革新,多次摸索实践,起先搞了一台     

一种精磨纸浆加工用混浆池混合装置

<正>申请公布号：CN 114941253 A发明人：冉孟怀申请人：江苏博汇纸业有限公司浆池是造纸企业广泛应用的一种设备，它是金属罐体设备，用于搅拌纸浆。在制浆流程中，需要对各个浆池中的纸浆进行搅拌，搅拌能使纤维、水及其他化工原料稀释与混合更加均匀，便于纸浆泵抽送到制浆流程中的下一个制浆设备；但是现有技术中的混浆池混合机构无法移动，只能对浆池的一块区域进行搅拌，容易使搅拌不均匀，     

离心循环搅拌器

目前我国造纸企业用的贮浆池,从形状可分为立式和卧式两大类。大部分城镇的造纸厂由于考虑减少占地面积,都采用立式贮浆池,但因其搅拌叶多为实心矩形,搅拌不匀,效果差,致使浆池内浓度不匀,白度不一致,严重影响纸的定量和质量。有时涡浆时间长了,     

玻璃纤维纱浆料调浆工艺条件的探讨

通过对现有浆料的工艺参数,如调浆温度、反应时间和调浆过程中的搅拌速度等探讨,确定了浆料的反应温度维持在90℃左右,反应时间40min,搅拌速度为120r／min和润滑剂L300含量为0．40％时,是最佳调浆工艺。     

改进真空洗浆机进浆槽

1进浆槽结构及存在问题真空洗浆机传统的进浆槽结构如图1所示，稀释黑液送进槽底夹层之间的横管内，由模管上的两排开孔流出，经槽底和逆止门翻流进槽内，搅拌辊以210r／min的转速在浆位下将纤维团破碎，浆料经过稀释搅拌后翻过堰板，进人鼓槽，楷体上部为敞开结构。这种结构在使用中存在以下问题。1．l搅拌效果差，上网困难。从图1可见，搅拌空间大，搅拌辊转速不高，纤维团不易破碎，浆料浓度难以图1传统进浆槽结构示意图l一清扫口；2一搅拌辊；3一隔板；4一逆止门；5一加黑液管；6一排气管；7一坦板。均匀、稳定，紊流的浆料在很短距离内…     

便于浆料收集的节水筛浆机

正实验所用筛浆设备,主要包括筒架、筛浆筒、筛板和出浆管,其原理主要是筛浆机采用高频振动式真空抽吸的方法,使符合要求的纸浆纤维从筛缝漏下去,不符合要求的纤维和浆渣留在筛板上面,然后除掉。筛浆机的振动是采用电动机带动偏心轴,使胶膜上下往复振动,产生真空抽滤纤维。料筒中有搅拌叶轮搅拌浆料,使浆料均匀分散。筛浆过程中要对所需的浆料进行收集,而且需要大量的水,通常在筛浆完毕后收集浆料时需要人工接浆,给实验带来不便,并且水直     

选用新型搅拌器,提高立式浆池功能

我国大部分纸厂对立式贮浆池选用很少,主要是立式贮浆池存在着浆料搅拌不匀、容积较小、泵浆困难等缺陷。对于现有立式贮浆池是否非淘汰不可?我们带着这个问题对我厂现存的立式贮浆池进行了初步的探讨和尝试。一、贮浆效果不好的影响因素我厂现共使用立式贮浆池四座。在生产上存在以下几个问题;上浆浓度波动频繁;易产生窝浆现象,浆泵易堵,运转率低,维修费用高;传动系统的零部件较易损坏. 上述问题我们认为:主要是由于搅拌系统不合理所致(见图1).     

喷放锅与高浓贮浆槽的设计

在造纸工业中,喷放锅和高浓贮浆槽已经使用好多年了。今天我们看到喷放锅和高浓贮浆槽的搅拌已从低速桨叶式发展到高速螺旋桨式。有些喷放锅仿效现代高浓贮浆槽的式样,具有从侧面伸入,并在直径缩小的圆筒底部运转的螺旋桨搅拌器。其他的则采用转子碎浆机结合搅拌,进行纤维的初步分散疏解。 但是,喷放锅和高浓贮浆槽的设计资料     

方形贮浆池的设计与应用

1贮浆池的形式目前贮浆池有卧式和方形两种形式。图1所示的卧式贮浆池是20世纪80年代以前普遍使用的贮浆池,这种贮浆池结构复杂,建造技术要求较高,施工困难,造价高,占地面积大,动力消耗大,建造过程结构尺寸稍有疏忽或搅拌设备选择不当均会影响其使用效果,特别是在浆料浓度较大时,浮浆、死角及上层停滞不动的现象经常发生。图2所示的方形贮浆池结构简单,为中空立方体,长、宽、高基本相近,能充分利用空间,占地面积小,施工方便,造价较低,可按车间场地灵活布置,池内浆料搅拌均匀,贮浆浓度高、动力消耗省。2方形贮浆池与卧式贮浆池比较方形贮浆池…     

啤酒厂糖化工艺心得（下）

（接上期） 主麦芽浆保持在35℃的糖化温度下,而部分麦芽浆在第二个容器中,在搅拌的同时加热至100℃。在部分麦芽浆持续35分钟的煮沸过程中,     

组合桨微波反应釜内流动混合特性数值模拟

针对微波反应釜搅拌混合均匀性问题,设计具有不同桨型组合的双层搅拌结构微波反应釜,其组合方式上下桨为推进式搅拌桨A100(A1)、上桨A200下桨A100(A2)和上桨A100下桨A200(A3)。基于计算流体力学CFD(Computational Fluid Dynamics)方法,采用层流模型、组分扩散模型和多重参考系方法对微波反应釜内醇油混合液的流动混合特性进行数值模拟,获得了具有3种不同组合桨反应釜内混合液的流动特性和不同加料位置下的混合时间特征。结果表明:组合桨A1釜内上下桨间存在一个轴向速度趋近于零的环流面,该面影响了釜内混合液的轴向流动混合;而组合桨A2、A3,改善了该环流面上的轴向速度分布,其最大轴向速度分别是组合桨A1的1.22,2.28倍,增强了上下桨间混合液的轴向迁移能力;加料点的位置会影响反应釜内混合液的混合时间,在理想加料点B加料时,组合桨A3的混合时间最短。     

Mechanism for the effect of agitation on the molecular weight of hyaluronic acid produced by Streptococcus zooepidemicus

Various views persist about the effect of agitation on hyaluronic acid (HA) molecular weight, and the mechanism remains unclear. In this paper, the effect of agitation on HA molecular weight was investigated. The HA molecular weight increased with impeller speed, due to a mass transfer enhancement; however, higher impeller speed caused a decrease in the HA molecular weight. According to the experimental results, it is proposed for the first time that reactive oxygen species (ROS) under higher impeller speed in the bioreactor, which were generated by NADH oxidase, could cause the reduction in the HA molecular weight. ROS generation increased remarkably during the exponential growth phase when the impeller speed increased from 450 rpm to 1000 rpm, and the NADH oxidase activity increased correspondingly. Finally, it was proved that the addition of salicylic acid could increase the HA molecular weight, but inhibit the efficiency of the HA synthesis.     

Comparison of heat transfer rates during thermal processing under end-over-end and axial modes of rotation

Thermal processing under conditions enabling container agitation are attractive to food processors since they provide higher rates of heat transfer and more uniform temperature due to product mixing. Two common types of agitations are end-over-end and axial agitation. While end-over-end agitation is common in batch retorts, axial agitation is predominant in continuous cookers in which the cans roll in a helical path along the retort shell. In this study, heat transfer rates to canned Newtonian fluids in end-over-end and axial modes of rotation were evaluated in the same retort. A single basket rotary retort was retrofitted to accommodate simultaneously both end-over-end and two types of axial modes of rotation, free axial and fixed axial. In the free axial rotation, the cans were allowed to rotate on their own axis as they rolled along the retort shell during the bottom third of the rotation, while in the fixed axial mode, the cans in the axial direction were held stationary in the rotating basket. The overall heat transfer coefficient U, heating rate index, lag factor and cook values associated with cans filled with Newtonian fluids were evaluated using a central composite rotatable design of experiments with glycerin at five concentration level (no glycerin to all glycerin), heating medium temperature (111.6-128.4 °C) and five basket-rotational speeds (4-20 rpm). Higher U, and lower heating rate index, lag factor and cook values were associated with higher rotational speed and retort temperatures for all modes of agitation. The heat transfer parameters associated with free axial rotation were significantly higher than in the end-over-end mode which was higher than in the fixed axial mode.     

Productivity of concentrated hyaluronic acid using a Maxblend fermentor

Application of the Maxblend impeller to the fermentative production of hyaluronic acid (HA) was investigated. A 2-m3-scale fermentor fitted with this impeller (MBF) was used and the main fermentation was started with 85% of the nominal volume containing the pre-culture broth and medium. The kinetic characteristics of the MBF were compared with those of a conventional-type fermentor fitted with a turbine blade (TBN). The HA production yield in the MBF was over 20% higher than that in the TBN under the operating conditions of a high aeration rate and low vessel pressure since the broth viscosity increased. The apparent viscosity of the broth at the end of the cultivation rose to about 70 Pa.s. The molecular weight of the HA produced was independent of the agitation speed within the investigated range, and no significant difference was observed between the viscosity-average molecular weights of the HA obtained in the two types of fermentor, each having an estimated value of 4.3 x 10(6) under the same agitation power.     

计算流体力学(CFD)在制盐行业中的应用及前景

介绍了制盐相关行业在CFD研究实践方面的工作。提出了在制盐行业的搅拌槽设计、轴流泵叶轮设计、洗盐工艺、提高传热效率、干燥床设计、结晶控制及结晶器设计等方面开展CFD研究的方向。指出了国内盐行业开展CFD研究的制约因素。积极开展计算流体力学研究,是制盐行业节能降耗,实现产业升级的重要途径。     

螺带式桨叶带宽对搅拌槽内油制辣椒固液两相流的影响

对油制辣椒固液两相流在搅拌槽内的流动情况进行数值模拟分析,选取螺带式桨叶,分析不同带宽条件下,搅拌槽内流体的速度场、密度场、各相体积分数分布规律。结果表明：螺带的带宽对搅拌槽内流体的流动分布有着较大的影响,通过比较不同帯宽桨叶可知,适当地增加带宽可以增加固液混合体的搅拌轴向速度,搅拌槽内湍流区域增加,固液搅拌均匀、效果明显变好。分析结果为油制辣椒卧式搅拌槽的设计提供了理论依据,具有一定的实际应用意义。     

螺带式桨叶带宽对搅拌槽内油制辣椒固液两相流的影响

对油制辣椒固液两相流在搅拌槽内的流动情况进行数值模拟分析,选取螺带式桨叶,分析不同带宽条件下,搅拌槽内流体的速度场、密度场、各相体积分数分布规律。结果表明:螺带的带宽对搅拌槽内流体的流动分布有着较大的影响,通过比较不同带宽桨叶可知,适当地增加带宽可以增加固液混合体的搅拌轴向速度,搅拌槽内湍流区域增加,固液搅拌均匀、效果明显变好。分析结果为油制辣椒卧式搅拌槽的设计提供了理论依据,具有一定的实际应用意义。     

低脉冲浆泵叶轮的三维造型及其内部的湍流数值模拟研究

用Pro／E软件对低脉冲浆泵叶轮的三维设计方法进行了研究，将AutoCAD下低脉；中浆泵叶轮二维木模图中的点参数转化为Pro／E下的．points文件格式，自动生成曲线，将曲线拟合成曲面后建立叶片与叶轮实体。然后将低脉冲浆泵叶轮的三维流道实体以STEP格式输出并导入商用CFD软件FLUENT的前处理软件GAMBIT中生成网格，选用两相湍流模型和SIMPLEC算法对纸浆在低脉冲浆泵叶轮流道内湍流场进行了数值模拟。     

Enhancement of Red Pigment Production by Monascus purpureus FTC 5391 through Retrofitting of Helical Ribbon Impeller in Stirred-Tank Fermenter

The possibility of using a novel proximity type half-pitched, double-flight helical ribbon impeller (HRI) for the improvement of red pigment production by Monascus purpureus FTC5391 was investigated in a 2-L stirred-tank fermenter (STF). For comparison, the fermentations were also carried out in STF equipped with the industrial standard six-bladed Rushton turbines (RT). The selection of aeration and agitation strategies in STF were based on possible attainable oxygen transfer at the start of fermentation using derived empirical power law model to predict the initial volumetric oxygen transfer coefficient (k _L a). The final pigment concentration, yield, and productivity obtained in optimized fermentation employing a single HRI agitated at 250 rpm and air flow rate of 2.25 L/min (1.5 vvm) was 24.36 UA₅₀₀, 0.47 UA₅₀₀/g glucose, and 0.20 UA₅₀₀/h, respectively. These values were about 76%, 78%, and 96% higher than those obtained in STF fitted with RT, respectively. In terms of impeller power consumption, the HRI system was favorable for batch cultivation of M. purpureus as pigment yield per energy invested was 2.5 times higher than the RT.     

Heat transfer phenomena during thermal processing of liquid particulate mixtures—A review

During the past few decades, food industry has explored various novel thermal and non-thermal processing technologies to minimize the associated high-quality loss involved in conventional thermal processing. Among these are the novel agitation systems that permit forced convention in canned particulate fluids to improve heat transfer, reduce process time, and minimize heat damage to processed products. These include traditional rotary agitation systems involving end-over-end, axial, or biaxial rotation of cans and the more recent reciprocating (lateral) agitation. The invention of thermal processing systems with induced container agitation has made heat transfer studies more difficult due to problems in tracking the particle temperatures due to their dynamic motion during processing and complexities resulting from the effects of forced convection currents within the container. This has prompted active research on modeling and characterization of heat transfer phenomena in such systems. This review brings to perspective, the current status on thermal processing of particulate foods, within the constraints of lethality requirements from safety view point, and discusses available techniques of data collection, heat transfer coefficient evaluation, and the critical processing parameters that affect these heat transfer coefficients, especially under agitation processing conditions.