半硬塑挤出瓦要限制泥缸升温

半硬塑挤出瓦由于它的规格形状特点,其较生产普通砖难度大,易产生各种缺陷,如横裂、纵裂、无规则裂、翘曲、分层等等.消除这些缺陷,人们往往多从泥条出口断面流速、真空度上找原因,并采取措施.经检测,大多数情况下真空度与泥条断面流速均符合工艺要求.这里忽视了一个重要的影响因素--挤出泥条温度太高,生产中常常出现55℃以上的高温,致使码坯烫手,而环境温度为:春季12℃～20℃;夏季20℃～31℃.挤出泥条温度与环境温度差距如此之大,造成坯体一出机口就急剧降温,瓦坯瞬间产生收缩,水分瞬间蒸发一部分,剩余水冷凝在坯体表面,也残存于坯体中(特别在春季),这就导致薄薄的瓦坯产生大量裂纹,瓦坯密度也受到一定影响.     

读者信箱

问:半干压瓦如何消除分层现象?答:粘土瓦的成型工艺有塑性成型、半干压成型和半硬塑挤出成型3种.由于湿法模压制瓦成型的瓦坯(将挤泥机挤出的泥片在压瓦机上压制成型)含水率较高,给生产带来一定困难.半干压成型则甩掉瓦托板,节约大量木材,降低成本,降低了劳动强度和成型含水率,减化了干燥工序,缩短了干燥周期,但控制不当也会出现一些问题,瓦坯内部分层即是其最常见的缺陷.瓦坯分层的实质是坯包气.瓦坯原料在被压制的过程中,空气没有及时地被全部排出,仍有部分来不及排出的空气滞留在瓦坯中,集中一处或多处使瓦坯分层起包,有时明显有时不明显,使出窑后的成品吸水率高,声音低哑,质量降低.     

浅谈烧结瓦坯的挤出成型

烧结瓦属薄壁制品,故其生产技术难度大于普通烧结砖,而其中瓦坯的成型工序是生产过程中的重要一环。瓦坯的成型方法分为模压和挤出两种。和模压相比,挤出成型的优点是：（1）简化了制瓦工序,去掉了模压成型时必须将泥料先挤成泥片再压制成型的工序,而是将制备好的泥料直接挤出成型;（2）减轻了劳动强度,取消了手工拉模,劳动生产率较高,产品成本较低。现就常用的挤出成型方法谈此看法。     

浅议真空度

在烧结砖瓦制作工艺中,为了提高泥料的成型性、均匀致密性以及坯体强度,使一些塑性低不宜制砖的劣质原料得到充分利用,使普通泥料能生产出薄壁、高强的空心砖,我们在挤出机上设计了真空室,将泥料进行真空除气处理,使存在于泥料内部的气体含量满足生产要求,以获得合格的坯体。我们     

浅谈烧结瓦坯的挤出成型

烧结瓦是深受人们喜爱的屋面防水材料。由于它属薄壁制品．故其生产技术难度大于普通烧结砖．而其中瓦坯的成型工序是生产过程中的重要一环。瓦坯的成型方法可分模压和挤出两种。与模压相比,挤出成型的优点是：简化了制瓦工序,去掉了模压成型时必须将泥料先挤成泥片再压制成型的工序．而是将制备好的泥料直接挤出成型：减轻了劳动强度．取消了手工拉模。劳动生产率较高．产品成本较低。现就常用的挤出成型方法谈些看法。     

德国觊乐公司舌形劈离瓦生产技术

Boral Dachprodukts公司在Riesa(地名)新建的一座砖瓦厂.第一次采用双泥片挤出技术生产舌形劈离平板瓦.和劈离砖的成型技术一样.舌形平瓦是成对侧立挤出成型.两片瓦中间有胁条.由于采用硬挤出生产工艺.瓦坯一挤出来就可以直接码运、堆放而不变形.它适合于多层(3～4层)直接码在干燥车进行干燥.该生产线由瀚德乐公司(Handle)和安拉盖哈(Anlagerhau)公司共同设计并提供粘土原料及硬质原料制备、原料贮存和成型工段的设备.硬塑     

不用人工修瓦模

在制瓦模子的四边上,镶上1×1×(1/4)或(3/16)吋的角铁,角铁的一面作为刀刃.上模子三个,下模子三个,也就是上下模子两旁都要镶,上下模子两头,一头镶一头不镶,但两个模子必须错开镶.使其上下两个模子结合时紧密,如方扣盒形,压瓦坯时能自动切断泥翅,产品楞角整齐,光滑美观,因此达到了不再用人工修瓦的目的了. 经过改进后的瓦模子口缝整齐严密,和上下模子压瓦坯时,模子外缘所镶的角铁“刀刃”和原有模子本身高出来的铁边,发生了挤力作用,因此在模子厌泥片时使泥不能随便向外跑,制出的瓦坯,内部组织细密坚实.     

提高瓦坯产量质量的有效措施

泥土经过水的媒介制成瓦坯,在干燥过程中主要的特性是收缩,湿坯体积的收缩量不仅因泥土种类而不同,并且因压制时所加水分的多少而不同.由于收缩的影响,往往使瓦坯发生翘裂,变成废品.为使其收缩量尽可能的减少,从而降低干燥损失,除适当地选择或配合泥土并控制其制造过程中所加的水分外,在自然干燥的生产方法中,更重要的是原料土的处理、制瓦的工具和操作方法、养护的关键和调节方法及管理制度等几个方面.兹将我省制瓦技术的几项具体措施介绍于后: 原料土的处理做好原料土的粉碎、湿化、搅拌工序,使瓦泥达到细密匀熟,是提高瓦坯质量减少损失的先决条件.     

浅谈烧结瓦坯的压制成型

<正>瓦坯的压制成型可分为塑性压制成型和半干压制成型两种,前者用得较为普遍。1瓦坯的塑性压制成型泥料经挤出机(如泥料塑性指数不高,应采用真空挤出机)挤出后切成泥片,根据泥料性能可困存7～15d或不困存。再送到压瓦机成型。     

浅谈烧结瓦坯的压制成型

<正>瓦坯的压制成型可分为塑性压制成型和半干压制成型两种,前者用得较为普遍。有些厂如广东省湛江耐火材料厂等采用了半干压制成型。1瓦坯的塑性压制成型泥料经挤出机(如泥料塑性指数不高,应采用真空挤出机)挤出后切成泥片,根据泥料性能可困存7d～15d或不困存。再送到压瓦机成型。泥片的挤出一般采用Φ320型双级真空挤出机或     

Applications of sewage sludge ash and nano-SiO2 to manufacture tile as construction material

In this study, various portions of potter’s clay and porcelain clay were replaced with incinerated sewage sludge ash (ISSA) to manufacture sludge ash tile specimens. We used these tiles to investigate the effect of introducing nano-SiO₂ particles as strengthening additives in the clay–ISSA materials. Percentages of ISSA in the porcelain or potter’s clay-based materials ranged from 0% to 50%, and fractions of nano-SiO₂ additives range from 0% to 3%. Tile specimens were manufactured from the different clay–ISSA–additive mixtures and sintered at kiln temperatures of 1000 °C and 1100 °C. Mechanical tests were performed to measure shrinkage, water absorption, abrasion, and bending strength. The sample microstructure was investigated using scanning electron microscopy (SEM). Chemical compositions of the tile specimens were characterized with X-ray diffraction. Results indicate that water absorption of porcelain and potter’s clay-based tiles was reduced when samples were fired at the higher kiln temperature, dropping to less than 12% in porcelain tiles at a kiln temperature of 1100 °C. Kiln temperature appeared to have less influence on the tiles made from potter’s clay. With the addition of nano-SiO₂ additive, the bending strengths of both types of tiles were increased, with the strengthening effect more pronounced in potter’s clay tiles when compared to porcelain clay tiles.     

Effects of contaminants on the properties of concrete paving blocks prepared with recycled concrete aggregates

The use of recycled aggregates for preparing concrete products has been successfully implemented and gaining wider acceptance. However, the allowable level of contaminating materials (e.g., crushed clay bricks, crushed ceramic tiles, waste glass cullet, wood chips, etc.) in the recycled concrete aggregate, in the some of the current specifications, is low (<1%) due to stringent quality control standards that are usually taken from specifications for raw granular virgin materials. This paper presents a recent study on the properties of concrete paving blocks prepared with recycled concrete aggregates that are contaminated by materials (tiles, clay bricks, glass, wood) commonly found in the construction and demolition waste. The density, compressive strength, tensile splitting strength, water absorption value, abrasion resistance, skid resistance and some durability parameters were measured for laboratory prepared samples. The results show that it is feasible to allow a higher level of contamination in the recycled concrete aggregates for making the concrete products. Recommendations are made on how the specifications could be revised to facilitate a wider application of recycled aggregates that is contaminated by foreign materials.     

陶土材料在外装饰工程中的应用

阐述了陶土材料的性能特点.结合工程实例,介绍了陶砖、陶瓦、陶板的施工工艺及操作要点.将陶砖、陶瓦、陶板用作屋面与立面装饰材料,使传统材料与现代建筑有机地结合在一起,既保持了传统风格,又表现出现代的时尚设计.     

Roofing finishes

Scientists at the Central Building Research Institute, CBRI, at Roorkee conclude, in a detailed study as part of their normal research programme, that good‐quality roofing tiles possessing adequate breaking strength and durability can be produced from properly blended and processed clay, either on a potter's wheel or on a tile‐moulding table.     

Polishing experiments on surface quality of building stone tiles

Polishing experiments were carried out on eight different carbonate stones with a machine designed for simulating industrial scale tile polishing process. Polishing was performed at 0.8, 1.3, 1.8 and 2.3 m/min belt speeds under fixed rotational speed and pressure of a polishing head. During the tests, calibrated stone tiles were sequentially polished with 60, 80, 120, 220, 320, 400 and 600 grit SiC abrasive stones at each belt speed. After polishing of each abrasive size, the quality of surfaces was assessed by measuring the surface roughness and gloss. As abrasive grit size gradually reduced to 320 grit, the roughness on the stone surfaces decreased greatly while gloss readings did not change significantly. But after 320 grit, gloss values increased greatly while change in roughness values was not significant. Reducing the belt speed resulted with a significant decrease in roughness for each grit size of abrasive, but after polishing with abrasive size larger than 320 grit, the influence of belt speed on the reduction in roughness values became less. Among the carbonate stones, micritic limestone tiles, which were homogenous in mineral composition with strong and hard structure, resulted with good surface finish. But clay minerals existing in other limestone and heterogeneous porous structure of travertines had an adverse effect on surface quality of tiles. Results from polishing tests suggest that belt speed value of 1.3 m/min provide optimum polishing quality conditions since optimum consistency in roughness and gloss of tile surfaces was reached at this belt speed. This findings were very valuable information for operating factories in which polishing is carried out. The gloss reading on stone surfaces was found to increase exponentially with decrease in surface roughness. Good correlation was found between surface roughness and gloss quality of micritic limestones and marbles compared to travertines.     

Semi-dry pressed tiles from alluvial deposits of northern India

Drying problems are greatly reduced when shaping tiles in semi-dry conditions write J.B. Bhatnagar, R.B. Hajela and R.K. Goel, of the Research Institute at Roorkee, where testing shows that better dimensional accuracy and finish can be achieved compared to traditionally made clay tiles at plastic or stiff plastic consistency.     

垃圾填埋场截污坝的渗漏分析与治理

介绍了某填埋场截污坝坝基和坝体的防渗措施,分析了调节池蓄水后截污坝发生渗漏可能存在的问题,利用物探、钻探和水质分析等技术手段,查明渗漏发生在混凝土芯墙和放空管接合部位,采用化学注浆和粘土填缝相结合的方法进行处理,取得了较好效果.     

Glazed tiles produced using paper sludge,glass cullet and a natural red clay: an experimental study

The paper describes the production, in single fast firing, of tiles containing 30 wt% of a natural red clay and a mixture of 42 wt% of paper mill sludge and 28 wt% of glass cullet which were coated with a commercial ‘matt white’ glaze. Fired materials have been characterized as a function of the top temperature (1090 or 1140 °C) reached at the top of the fast sintering process made by an industrial roller kiln. It has been observed that tiles fired at 1090 °C display the best overall performances because the matt glaze well covers the substrate, thus ensuring that the mechanical and physical properties of the tiles conform to the official standard.     

从“国抽”结果探讨陶瓷砖质量管理与提升策略

产品质量监督抽查是国家质量监督行政部门对涉及人身、财产安全的产品,影响国计民生的重要工业产品及消费者、有关组织反映有质量问题的产品进行的有计划的抽样、检验,被称为“国抽”。陶瓷砖属于“国抽”产品。本文根据2018-2021年的“国抽”结果进行分析,探讨陶瓷砖质量管理与提升策略。     

V型滤池滤砖施工中的质量控制

分析了原V型滤池配水系统（陶瓷滤砖）存在的布气不均匀等问题，制定了相应的整改方案，将陶瓷滤砖更换为塑料滤砖，并加强了施工期的质量控制和监管，达到了预期的改造效果。