氨液分离器堵塞的处理对策及预防

在冷库重力供液系统中,氨液分离器是不可缺少的关键设备。它是用来分离节流后的低压氨液中所带的无效蒸气(俗称闪发气体)以及分离蒸发器回气中的氨液,同时当分配调节站向同一楼层的几个蒸发器供液时,还起到调剂分配氨液的作用,氨液分离器安装时还有一定的高度要求,使之产生一定的液柱压力,克服管道的摩擦阻力和局部阻力,使氨液能很好地充满冷却管组和保证制冷剂的正常循环。     

介绍一种船用氨液分离器及其系统

本文从实际出发，分析了引进设备在制冷工艺方面的特点性；从工艺参数，氨液分离器结构和蒸发器分布等几个方面进行了介绍，并对其设计特点加以探讨。     

对国外一种氨制冷系统的改造

分析了将氨液分离器设计安装于低温冷库内的氨制冷系统的缺点，提出将氨液分离器及相关阀门搬迁至库外，改变热氨冲霜回液管设计的解决方法；并提供了氨液分离器安装高度的一种计算方法。     

制冷系统气液分离器的研究现状分析

气液分离器已经应用于多个行业领域,但气液分离器在制冷系统中的研究还较少。本文简要介绍了气液分离的基本机理,在此基础上总结了制冷空调系统中气液分离器的研究现状,并提出研究应用于制冷系统中其他形式高效气液分离的可行性和应用前景。     

满液式供液系统中氨液分离器保温问题初探

在冻结装置中,有一种特殊形式的重力供液即满液式供液,它是将氨液分离器与蒸发器设在同一层上,利用液体的均压作用,使氨液分离器和蒸发器内液面趋向一致,它的液面高度保证排管容积的60～80％存有液体。其优点是可以免除重力供液系统中静液柱压力对蒸发压力的影响,保证系统达到所设计的蒸发温度,同时可以节约建筑投资。 在满液式供液系统中,氨液分离器必须靠近蒸发器,所以,目前在冻结库中,一般采用将氨液分离器设置于冻结间内的方案。在冻结间内氨液分离器是否需要做     

空调气液分离器设计研究

对空调在使用过程中所出现的回液及液态制冷剂进入压缩机的现象进行了分析并指出了其危害性;同时提出了针对性的改进措施,对空调气液分离器的应用及优化设计,尤其是回油孔的设计进行了详细的阐述。实践证明合理地设计及应用气液分离器,对提高空调产品的可靠性具有十分重要的意义。     

泵供液制冷系统低温管道保温厚度的优化

建立典型的氨泵供液单级压缩制冷系统和氨泵供液双级压缩一次节流中间完全冷却制冷系统的吸气管、回汽管等低温管道的传热数学模型和低温管道年总消耗费用的经济模型.基于传热模型、经济模型和氨的热力特性模型,用VB6.0语言分别编制适合于氨泵供液单级和双级压缩制冷系统低温管道保温层厚度的优化设计程序.利用优化程序对厦门地区某大型水产冷库低温冷藏库回路的低温管道保温层厚度进行实例优化设计计算,结果表明:与传统设计方法选用的保温厚度比较,程序选用的最佳经济厚度可使管道的年总消耗费节省5.4%.     

美国谷轮公司压缩机应用技术讲座 第十四 讲压缩机常见故障分析（2）——液击

液击是往复式压缩机的致命杀手,往往会在很短时间内造成阀片破碎、连杆和曲轴弯曲甚至断裂.液击是由回液、带液启动等引起的,是系统问题在压缩机上的表现.提升制冷系统的设计、施工和维护技巧可以从根本上防止液击的发生,正确选择和安装膨胀阀、气液分离器、热气旁通阀和曲轴箱电热器、定时化霜、以及避免库温频繁波动是防止回液的具体措施.     

氨制冷技术在天然气水合物中试中的特殊应用

本文具体分析了氨制冷技术在天然气水合物中试试验中的两个特殊应用:一是氨液分离器压力控制;二是氨压缩机出口热源应用.从实际运用看,效果良好.     

浅谈制冷压缩机吸气状态与湿冲程

在制冷系统里,压缩机的实际运行中,由于系统热负荷的变化,压缩机开机数量的改变,供液调节阀和回汽阀开启的变化等等原因,压缩机的吸入状态也是经常变化的,操作人员若能及时判断压缩机的吸入状态是过热、饱和或过湿,对压缩机湿冲程的预防是极为重要的。     

The dynamics of wet granular matter under a vertical vibration bed

This study investigates the dynamic properties of convection rolls in a 2D wet vibrated granular bed. A particle tracking method with the help of image-processing technology was used to measure the velocity fields, convection flow rate, and the granular temperatures in the wet vibrated granular bed. This study examines the dynamic behaviors of wet granular materials subjected to external vertical vibration. Different liquid contents, viscosities, and surface tensions were added to glass beads forming cohesive granular materials in the vibrated granular bed. This study presents a systematic investigation of the effects of the addition of liquid content, viscosity, and surface tension on dynamic properties of wet particulates. Results show that the convection flow rate and granular temperature decrease monotonically as the added liquid content and liquid viscosity increase. However, the effects of surface tension on the convection flow rate are more significant at the smaller liquid content than that at a higher liquid content. The convection flow rate also decreases in a power decay as the modified Bond number increases.     

Influence of interparticle forces on selective wet agglomeration

The influence of interparticle forces between primary particles, which include interaction force between dispersed particles in liquid calculated by DLVO theory and two kinds of forces caused by a liquid bridge of bridging liquid between particles, on selective wet agglomeration was investigated on the basis of the relationships between the results of separation efficiency obtained in author’s previous study and these interparticle forces. The first step of selective wet agglomeration is the collision between bridging liquid droplets and objective particles to be agglomerated. This collision is mainly influenced by the interparticle force calculated by DLVO theory. Incorporation of two objective particles, the second step in the agglomeration process, is influenced by liquid bridge force between objective particles. Growth to pellet-type agglomerates, the third step in the agglomeration process, is thought to be influenced mainly by aggregation force in the agglomerates by entry suction potential. The results of this study showed that selective wet agglomeration under the experimental conditions used in this study is influenced greatly by liquid bridge force and entry suction potential, which play major roles in the second step and third step, respectively, of the selective wet agglomeration process.     

悬臂梁-流体-悬臂梁耦联系统的湿模态相互作用

应用流体的势流理论及悬臂梁振动方程，本文分析了悬臂梁-流体-悬臂梁耦联系统的自由振动问题。分析表明，悬臂梁除与流体发生相互作用外．两悬臂梁湿模态通过流体的耦合也发生相互作用．后者的作用使流固耦联系统的湿模态呈现新的振动特性．同一阶两个子结构(梁1，2)各自的干模态分别对应耦联系统同一阶的两个湿模态．一个以较低的湿频率出现，两梁呈反相位振型，另一个以较高的湿频率出现，两梁呈同相位振型。     

Effect of collision angle on particle-particle adhesion of colliding particles through liquid droplet

In wet granulation processes, a particle adhesion mediated by a liquid bridge is one of the quite important phenomena. In an actual process, the liquid bridge shows dynamic motion due to continuous motion of the particles. Therefore, understanding of the particle adhesion phenomenon by a dynamic liquid bridge is essential to adequately and precisely control wet granulation processes. This study presents a direct numerical simulation of the particle–particle adhesion by a dynamic liquid bridge. Collision of a dry particle and a wet particle was simulated at various collision angles. In particular, translational and rotational motions of the particle at different collision angles were discussed through comparison with a conventional static liquid bridge force model. As a result, it was found that both translational and rotational motions were largely different between simulation results of the direct numerical simulation and static liquid bridge force model, especially at the tangential collision. To understand these results, we focused on the rotational behavior of the particle and deformation of the liquid bridge. It was concluded that the non-slip behavior of the liquid bridge on the particle surface is a key phenomenon for the particle-particle adhesion by the dynamic liquid bridge at the tangential collision.     

焓差室回风口处干湿球温度取样器内不同风速下额定制冷量偏差的计算方法

通过数学公式推导并结合经验数据给出了焓差室回风口处干湿球温度取样器内不同风速下额定制冷量偏差的计算方法。     

Influence of Technological Factors on the Optimal Granulation Liquid Requirement Measured by Power Consumption

The optimal liquid requirement for wet granulation can be investigated by recording the power consumption of the mixer during liquid addition. In this work it was tried to use this technique on a small laboratory scale (one kg or less) for lactose wet granulation with water. The validity of the power consumption method could be confirmed by granule size analysis. Different factors were studied: kind of mixer, powder quantity, mixer speed, liquid addition speed, granulator screen size, mixing time.     

Influence of Technological Factors on the Optimal Granulation Liquid Requirement Measured by Power Consumption

Abstract

The optimal liquid requirement for wet granulation can be investigated by recording the power consumption of the mixer during liquid addition. In this work it was tried to use this technique on a small laboratory scale (one kg or less) for lactose wet granulation with water. The validity of the power consumption method could be confirmed by granule size analysis. Different factors were studied: kind of mixer, powder quantity, mixer speed, liquid addition speed, granulator screen size, mixing time.     

液氧泵回流阀爆裂事故原因分析

介绍一起液氧内压缩流程中液氧泵回流阀爆裂事故的经过和破坏情况,初步认为事故的原因可能是阀门制造缺陷导致升压过程中上阀体破裂后高压液氧泄漏,进而引发化学性爆炸。最后提出了防止液氧泵回流阀燃爆的预防措施。     

Quantitative evaluation of kneading and extrusion processes by pressure transmission characteristics of wet kneaded masses

This study is devoted to the quantitative evaluation of wet kneaded masses prepared by a paddle-type kneader, and the analysis of the kneading process and the following extrusion granulation process. A compaction tester of wet kneaded masses has been developed and the compression properties of the masses are characterized by a pressure transmission between the upper and lower punches of the tester. The dispersion condition of a binder liquid among the wet kneaded masses prepared under various kneading times is investigated. The extrusion pressure through a single ejection hole on the lower punch is also measured. The pressure transmission is found to have a linear relationship between the dispersion of binder liquid and the extrusion pressure. This results lead to a conclusion that the proposed method provides the generalized measuring means of wet kneaded masses. An extrusion granulation by a dome-type extruder is conducted using wet kneaded masses and physical properties of the extruded pellets (granules), such as friability, specific surface area and disintegration time, are investigated. Good linearity can be found between the pressure transmission and the physical properties of the pellets. As the result of these findings, the kneading condition, i.e. the dispersion of binder liquid among the wet kneaded masses, can be quantitatively analyzed and the physical properties of pellets prepared by extrusion granulation can be accurately predicted by the pressure transmission measured by the newly developed compression tester.     

Ontogenetic changes in the olfactory antennules of the shore crab,Hemigrapsus oregonensis,maintain sniffing function during growth

Malacostracan crustaceans capture odours using arrays of chemosensory hairs (aesthetascs) on antennules. Lobsters and stomatopods have sparse aesthetascs on long antennules that flick with a rapid downstroke when water flows between the aesthetascs and a slow return stroke when water is trapped within the array (sniffing). Changes in velocity only cause big differences in flow through an array in a critical range of hair size, spacing and speed. Crabs have short antennules bearing dense arrays of flexible aesthetascs that splay apart during downstroke and clump together during return. Can crabs sniff, and when during ontogeny are they big enough to sniff? Antennules of Hemigrapsus oregonensis representing an ontogenetic series from small juveniles to adults were used to design dynamically scaled physical models. Particle image velocimetry quantified fluid flow through each array and showed that even very small crabs capture a new water sample in their arrays during the downstroke and retain that sample during return stroke. Comparison with isometrically scaled antennules suggests that reduction in aesthetasc flexural stiffness during ontogeny, in addition to increase in aesthetasc number and decrease in relative size, maintain sniffing as crabs grow. Sniffing performance of intermediate-sized juveniles was worse than for smaller and larger crabs.