玻璃厂毕业设计外文翻译----玻璃熔窑的最优设计.docx

外文资料OUR TRIBUNEWHAT IS THE BEST DESIGN FOR A GLASS FURNACEN. Ya. Suvorov(Kurlov Glass works)During 195354 there was a discussion in Glass and Ceramics on the design of tank furnace. The discussion was very informative for workers in the glass industry, for it acquainted them with the existing views on this matter, although it was not completed by the presentation of conclusions relating to the courses to be followed in the design of glass furnaces.It must be acknowledged that science has not yet succeeded in making a complete study and systematization of experience gained in the operation of glass furnace and has not yet been able to tell us how to design furnaces that will correspond to the present level of knowledge and technology.What is the fundamental principle which ,in our opinion ,must form the basis of the design of perfect tank furnaces ,It will be obvious that by a perfect tank furnace we mean one that is as efficient as possible in technical and economic respects .The design of a tank furnace must be such that the melted glass passed to the machines in strict sequence .For example, if the capacity of the furnaces is 1000 tons of glass and the machines only after ten days.We consider that the time has come when it should be possible to arrive at a well grounded conclusion concerning the distribution of currents of glass in tank furnaces and to design a furnace accordingly, so that our basic principle of the strict sequence of the melted glass to the machines can be realized.It is essential to eliminate undesirable currents of glass and the formation of layers differing in composition, i.e.to keep the kinetics of glass within limits set by the special design of the tank furnace, by the heating schedule adopted, and possibly by the mechanical action exerted ion the melted glass .Our proposed design for such a furnace is represented in figures 1-6.We do not consider that the problem of constructing a glass tank furnace of our design is more difficult than many others problems already solved by science and technology. The solution of this problem is within the power of our planning and erection organizations.In the light of the requirements that we have made with respect to the design of glass furnaces, the tanks of the very large tank furnace now in use in the glass industry give the impression of large frying pansin which ,at the glass surface , the glass is not melted but roasted,and in the roasted condition ,after being cooled for 10-12 hours, is passed to the machines.When such apparently well-melted glass is examined optically, it is found that there are innumerable defects: streaks, whirls, stripes, threads, etc. ,which differ from the surrounding mass .Such a glass is non-uniform in mechanical and technical properties ;the productivity of the machines is not as high as it might be and the glass is of lower utility.In the manufacture of optical glass these defects are eliminated by prolonged stirring of the glass with special stirrers. In the manufacture of sheet glass, pressed ware, etc., no effort is made to overcome these defects, and all is left in the care of the laws of thermal movement in the glass mass.Rapid cooling of glass, particularly when there in a negative pressure over the glass surface in the cooling zone not to speak of the use of coolers and blowers results in the formation of layers differing in viscosity and therefore in the production of glass full of whirls and waves ,varying in thickness ,badly annealed ,not thermally durable ,giving much breakage during processing ,and not durable in use. Slow cooling gives glass that is more stable against leaching .Rapidly cooled glass has different physicochemical properties than the same glass cooled slowly, We cannot agree with the assertion that glass ,having attained to a definite degree of clarity during melting ,cannot be submitted to a temperature higher than that previously attained, nor with the recommendation that cooling should be rapid and so fix the state of the glass with all its established and non-established equilibria .Also, we cannot accept the advice that we should always adjust the atmospheric regime of the furnace to the course of the melting process .Such advice is theoretical and cannot serve as a guiding principle for production personal. Prevention of the overheating of the glass by increase in the dimensions of the furnace or with the aid of coolers and ventilators must be regarded as highly erroneous.The main and greatest defect of large tank furnace and of all furnaces in general, particularly those without barriers (floating bridges, bridge walls etc.) is that the upper layer of glass moves very rapidly to the working end .This has many undesirable consequence, particularly in the non-barrier method of forming sheet glass by vertical drawing machines.We maintain that glass of the upper, working layer, moving over the intermediate layer disposed between it and the oppositely moving lower layer, particularly entraines glass form the intermediate layer. In its turn, glass of the upper layer partially falls into the intermediate layer. These processes bring about the physicochemical and thermal non-uniformity of the glass the cause of all of the defects indicated above. We consider that in existing tank furnaces-particularly in very large furnace-at least 90% of the glass entering he machines has been carried there within 12-16 hours after melting by the main working upper layer of the glass mass, which is formed at the hottest mass point of this view can be readily confirmed by coloring the glass mass. From our knowledge of the formation of currents in melted glass in tank furnaces we concluded that it is necessary to learn how to control these currents, to eliminate their harmful effect, and to cause them to assist the process by mixing the layers of glass together and bringing about their homogenization. There is no need to say very much about the harmful effects of the layers of glass disposed below the upper working current in existing glass tank furnaces, particularly those of large dimensions. If the use of furnaces of large dimensions has effected some improvement in the unfavorable effect of the direct feeding of the machines with glass from the tank furnace . Our large furnaces do not have high specific outputs, whereas we know from the technical literature that furnace of 1500 output and higher are in existence. In our opinion tank furnaces provided with throats deserve attention. At the technical literature that furnaces for the manufacture of glass of all kinds , apart from special glasses. The results of the experiments that have been carried out on the manufacture of sheet glass in furnaces provided with throats are not conclusive, and it is very unfortunate that, owing to an insufficiency of fuel and batch, such excellent furnaces have been tested under such unfavorable condition. We wish to design a glass tank furnace in such a way that the working stream passing to the machines shall not be in the upper layer of the glass, but in the lower layer .Only under these conditions will the physicochemical and thermal homogeneity be attained which will confer good working properties of well-annealed sheet glass without thickness variations with a minimum of breakage. When the working current in a glass tank furnace becomes the lower layer , the imperfection in the glass which occur in tank furnaces having an upper working current are eliminated . The glass will be renewed throughout the whole tank within a strictly definite period of stagnation-in the tank and in the channel at the working end-which we maintain are the main sourced of stripiness, thickness variation, friable places, and threadlike whirls. This view is confirmed by results of the production of sheet glass from bridgeless tanks with direct feeding of machines from the tank furnace.As can be seen from the diagrams showing the principle of the design of our proposed glass tank furnace, the bottom of the tank is not horizontal throughout its length and breadth, so that the depth of the tank varies correspondingly. The bottom slopes towards the throat, the fall in level being 400-800mm. The fall from the side to the center of the bottom is 200-500mm. The bottom of the furnace is therefore in the form of a gutter. The bottom being of this form, the glass is bound to move over its sloping surface in the direction of the throat. The glass will move also from the sides of the tank bottom to the center of the tank and, mixing with the central stream and becoming homogeneous, pass into the throat (fig.3).It will be seen from the temperature curve that the maximum temperature occurs at the end of the furnace near to the throat. Since the glass moves along the bottom in the direction of the throat and the maximum temperature is at the throat, the upper layer of glass will move from the throat toward the dog house and, acquiring increased density and homogeneity, fall into the bottom layer and move into the throat as a lower working layer. We are convinced that in a tank of this design operating under the given temperature conditions there will be no return current of glass moving along the bottom in the direction of the dog house1.It will be seen from Fig.4 that the crown of the tank furnace rises from the throat in the direction of the dog house. A crown of this sort is essential in order to establish the necessary temperature distribution in the furnace (Fig.2) and also so that any air-carried swirls of batch will be carried away to the dog house by the upper currents of hot gases. The ports and crown must be as low as possible over the tank furnace. The ports in the upper part must be unified with the crown of the furnace (Fig.5). The burners must differ in cross section and in the directions of their flames. The arrangement of each pair of burners depends on the direction of the flame, the desired gaseous medium in that particular region, and the pressure over the glass surface. In the existing tank furnaces, all of the burners are usually identical and the regenerator chambers are common to all of the burners, so that it is extremely difficult to regenerators on some works has made it possible to change the filling of the regenerators without shutting down the furnace. In addition, it is essential that each section of the regenerators should have its own supply of gas and air, which is the necessary condition for the regulation of the working of the burners2. The reserve of draft in the flues should be so great that, irrespective of the extent to which the regenerators are choked, it is always possible to regulate the supply of air and gas to the burners so as to give the required direction and character to the flame. We stipulate the following dimensions and temperature distribution for the tank furnace: length of tank-minimum 10 m, maximum 20 m; width of tank-minimum 5 m, maximum 10m;fall in level of bottom from dog house to throat 0.4-0.8 m; fall in bottom from side to center 0.2-0.5 m; temperature near throat 1490-1500; temperature in the region of the first burner near the dog house 1430-1440. Tank furnaces should be planned to give a productivity of at least 100-400 tons of melted glass per day a yield of at least two tons of glass from each square meter of melting area. The melting area is regarded as the whole area of the tank form the dog house to the throat. There is no cooling part in the tank furnace; it is replaced by the slow sinking of the glass into the working layer at the bottom. As can be seen from Fig.2.the glass passing from the throat moves upwards, crosses a baffle as a layer 300-800 mm in thickness, and so proceeds into the working section. The volume of the working end should be equal to a days production. The level of the bottom of the working end falls by 500-600 mm from the baffle to the machines (only as far as the neck, in the cause of sheet glass machines). The depth of the channel is 1200 mm. All the dimension of our proposed glass tank furnace are determined by the physicochemical properties of the glass, temperature distribution, the time of sojourn of the glass in the tank, the productivity, and the quality of the gas(it is desirable to use purified gas, for the use of unpurified gas necessitates increase in the dimensions of the furnace).The glass industry has refractory materials at its disposal which make it quite possible to construct a glass tank furnace to our design. The author is now occupied in drawing up a working plan for a glass tank furnace of this type.外文资料译文玻璃熔窑的最优设计在1953-1954年期间，有一个关于玻璃和陶瓷池窑设计的讨论。虽然这次讨论不是以玻璃池窑设计相关课程结论介绍完成的，但是对玻璃行业的人来说，这次讨论还是非常有意义的，因为这次讨论让他们熟悉现有的关于玻璃池窑设计的新想法。必须承认的是，科学还没有成功的做出一个完整的有关玻璃池窑研究，也没有获得系统化的玻璃池窑运作的经验。同样，科学也没能告诉我们如何设计符合现代知识和科技水平的玻璃池窑。什么是玻璃池窑设计的基本原则，我们并不知道，但这个原则一定是在设计完美玻璃池窑的基础上。很明显的是，我们心中的“完美玻璃池窑”是指一个既具有最新技术又经济使用的玻璃池窑。一个池窑的设计必须满足熔融玻璃液以严格的连续性传递给生产机器。例如，如果池窑容量为1000吨，而机器每天只产100吨玻璃液，那么只有在十天之熔融玻璃液才能达到机器容量。我们认为，现在实现这一基本原则的时机已经来临，我们应该有可能得出一个关于玻璃熔窑中流量分布的基本结论，也有可能根据此设计一个相应的玻璃池窑。这样就使熔融玻璃液以严格的连续性传递到机器中得以实现。关键是，为了消除我们不期望看到的玻璃流动以及因玻璃成分不同所造成的玻璃液的分层，也为了保持玻璃在极限内的流动性，我们可以通过设计特殊玻璃池窑，可以通过采用加热原件，也可以通过玻璃液的机械流动。我们所提出的池窑设计会在图1-6得到体现。我们并不认为，建设我们的设计玻璃池窑所遇到的问题比已经由科学技术解决的许多其它问题更棘手。因为解决这些问题方法在我们的计划建造队的能力范围之内鉴于我们已经在玻璃池窑设计方面所提出的要求，目前在玻璃行业中使用的超大玻璃池窑的窑给人们留下深刻的“炸锅”印象，从玻璃表面上看，玻璃不是熔化了，而是被“烤”化了，并且在烤的条件，冷却10-12小时，再被传递给生产机器。当这些看似明显良好的熔融玻璃经过光学检查时，却发现有无数的缺陷：条纹，旋涡，线条，线程等，这些外界气氛造成的缺陷和因组成、耐火材料侵蚀所造成的缺陷不同 ，这种玻璃的机械和工艺性能也会不一样。生产这种玻璃的机器的生产效率可能要低，而且生产的玻璃使用率低。当这些看似明显良好的熔融玻璃经过光学检查时，却发现有无数的缺陷：条纹，旋涡，线条，线程等，这些外界气氛造成的缺陷和因组成、耐火材料侵蚀所造成的缺陷不同 ，这种玻璃的机械和工艺性能也会不一样。生产这种玻璃的机器的生产效率可能要低，而且生产的玻璃使用率低。制造光学玻璃时，需用特殊玻璃搅拌器搅拌来消除这些缺陷。而制造平板玻璃时，像压制品等，很容易消除这些缺陷，而且这都是“玻璃液大规模热运动”的结果。对于急冷玻璃，尤其是当在玻璃冷却区玻璃表面是负压的，会导致玻璃液因粘度不同分层，因此生产的玻璃充满了螺纹和波筋，厚度不均匀，退火不良，耐热性不良，而且加工过程中会产生许多裂纹，不经久耐用。更不用说使用冷却器和鼓风机，生产的急冷玻璃。慢冷玻璃更加稳定。急冷玻璃与同种慢冷玻璃相比具有更好的物理化学性能，我们不同意在熔化过程中获得一定透明度的玻璃不能达到比以前获得的更高的温度这样的论断，也不符合玻璃液冷却应迅速和通过已建立或未建立的平衡来固定玻璃的状态这样的共识。同样，我们不能接受的意见就是为了满足玻璃熔化工艺总是调节玻璃熔窑气氛。这种意见只是理论性的，不能作为个人生产的一个指导原则。通过增加池窑尺寸或者在冷却器和通风设备的辅助下来阻止玻璃的过度升温，这种想法真是太荒谬了。大型池窑和所有一般池窑，特别是那些没有障碍（浮桥，桥墙等）的池窑主要的也是最大的缺陷就是上层玻璃液会非常迅速流到熔化部的末端。这就带来了许多不良后果，尤其是通过非立式拉丝机无障碍法形成平板玻璃的方法。我们坚持认为，玻璃液的上层，工作层在中间层上面移动，下层会被带动向反方向移动，部分中间层的玻璃液会下沉。反过来，上层玻璃液部分变成中间层。这些过程就造成玻璃物理化学不均匀性和热不均匀性，以上已说明玻璃所有缺陷形成原因。我们认为，在现有的池窑，特别是超大池窑（也就是至少90的玻璃进入生产机器），能成形的大量上层玻璃液通常是在池窑的热点形成的，而且熔化后的玻璃液在12-16小时内能流到生产机器里面的。这种观点的正确性已经在着色玻璃质量中得到了证实。从我们对玻璃池窑内熔融玻璃液形成的流动性的了解，我们可以得出这样的结论，学会怎样控制玻璃液的流动，学会怎样消除其有害影响，学会怎样通过混合多层玻璃液并均匀化来优化工艺过程，这都是有必要的。在现存玻璃池窑，尤其那些大型池窑，上层玻璃液流动会对下层玻璃液带来有害影响，但我们没必要非常关注这些有害影响。如果要说使用大尺寸池窑会对平板玻璃的质量有所改善的话，那么这种改善也是非常微小的，因为把玻璃液直接从玻璃池窑喂到机器里面也会带来不好的影响。我们的大型玻璃池窑并没有特别高的产出，然而我们从技术文献中可以了解到1500/或者更高产量的池窑都是存在的。 在我们看来，玻璃池窑设置卡脖是值得关注的。在当时，对于各种玻璃制造，除了特种玻璃，这就是设计最好的玻璃池窑。我们在设置卡脖的玻璃池窑中进行了平板玻璃生产的实验，实验结果并非最终定论，但非常不幸的是，燃料和配合料不充足，但是完美的玻璃池窑还是在如此不利的条件下完成了生产测试。 我们希望设计一个玻璃池炉，在这种池窑中应该是下层玻璃液