玻璃幕墙的“玻璃变形”四大因素.doc

。幕墙玻璃变形的原因？What actually results in glass image deformation?在幕墙门窗工程项目中，关于玻璃安装后的成像变形的问题，很多时候开发单位及施工方都会归结于“钢化变形”，但实际上引起玻璃成像失真的原因有很多，各种因素对失真的影响也不尽相同。When imaging distortion happens in the curtain wall/ windows and doors projects, people always blame for tempering deformation. But as a matter of fact, there are many other reasons for it, and all those reasons have different influence on the glass image formation.引起玻璃变形，主要有以下四个因素：Lets see the four main possible reasons as below:一、玻璃原片与加工因素 The raw glass sheet and the machining process原片：我们通常看到的玻璃成像都是光线穿过玻璃被反射回来的影像。衡量原片光学变形的是斑马角，根据我国的浮法玻璃标准，建筑级玻璃的斑马角需达到50度，汽车级和制镜级的玻璃则要求达到60度以上；而国外高档浮法玻璃的斑马角可以达到70度以上。Raw glass sheet: The ray of light passes through the glass and reflected that is how the image formation comes. Usually we use zebra angle to measure the optical distortion of glass sheet. According to our domestic criteria for float glass the zebra angle of glass used for architecture shall be 50, while those for automobiles and mirror-manufacture shall be over 60. And for some high-end float glass abroad, it can reach over 70.（斑马角：在距离观察者9米远处放置一斑马幕，在斑马幕与观察者中间放置玻璃样品，观察者透过玻璃样品观察斑马条纹，首先让条纹变形，然后慢慢转动试样直到形消失，记录此时玻璃法线与视线的夹角，简称斑马角，通常用斑马角的大小来评价浮法玻璃的光学变形。）(Zebra Angle: Place a pinto screen 9 meters away from the observer and a glass sample between the two. Then the observer looks at the image through the glass. When the image begin to deform, turn the sample until the image disappear. The angle between the glass normal line and the sight, we call it the zebra angle and it is usually used to measure the optics deformation of float glass.)钢化：钢化是对原片进行二次热处理的过程，钢化过程中的畸变确实会对成像产生较大影响。一般来说，如果钢化玻璃中部出现畸变，可以认为是由于工艺控制出现严重问题。Reinforced: It is the reheat treatment for the glass sheet. The deformation caused by it makes a great difference on the image formation. Normally, we can blame it for the technical control problem.实际上如果钢化弓形度控制在1，波形度控制在0.15mm，再采用宽边进炉措施的话，成品的最终变形与钢化生产的关系并没我们想象那么大。Actually if we can control the arch within 1 and waveform within 0.15mm, also put the broadside into the furnace, reinforcing will not have that great influence.中空：中空玻璃合片后的凸起或凹陷对玻璃成像变形影响很大。一般情况下，空气中含有1-4%的水蒸气，湿度越大水蒸气含量越多。中空玻璃生产完成后，分子筛会吸收掉大部分密封到中空内的水蒸气，故中空玻璃常呈现凹陷状，当然水平打胶压凹应该是加工质量控制的问题。Insulated: Insulated glasses concave-convex influence the image formation a lot. Generally speaking, the air composed of 1-4% vapor. The higher humidness, the more vapor in the air. When the manufacture is finished, molecular sieve would absorb the most vapors in the insulated glass. And thats how the sunken shape comes. By the way, horizontal sealant applying may also cause hollowness and processing quality control shall be responsible for it.二、设计选型因素 Design and type-selection玻璃厚度：目前国内在设计玻璃进行扰度计算时，一般控制在最大风压负荷的1/60，而国际上一般是按1/901/120来进行核算的，这种算法导致我们国内选用的玻璃比较薄。玻璃越厚刚性越好，成像变形也越小。这也是在香港或者国外，幕墙玻璃看起来平整度比较好的原因，一般他们的幕墙玻璃选用10 mm的居多。Thickness: In China, when we calculate the deflection, normally we will control it within 1/60 while internationally, within 1/90-1/120. Therefore, the glass we select domestically - is relatively thin. Greater thickness means less image deformation. We can see curtain wall glass in HK and foreign countries win better flatness. They use 10mm thick glass the most.反射率：反射率越高的玻璃成像会越清晰，事实上也越容易观察到玻璃的变形。Reflectivity: The great reflectivity, the higher-quality for image formation. Actually at the same time, it is easier to observe if any deformation.长宽比：玻璃长宽比太大容易产生扭曲变形，长宽比太接近1:1则容易出现锅底形，一半来说最佳的长宽比是2:1。Length-width ratio: Distortion may happen when the length-width ratio is too high. Sunken shape may happen when ratio is near 1:1. Actually, 2:1 is the best choice.三、环境因素 Environment对于中空玻璃来说，腔体内空气受到温度、压力等变化的影响会膨胀或收缩，对其成像的影响也很大。As for insulated glass, the volume of air inside will be influence by the changes of temperature and pressure. And this makes a difference on the image formation.气温：中空内空气温度升高或降低15度，密封在中空玻璃内部空气体积将膨胀或收缩5%。Temperature: The air temperature increase of decrease 15, the volume will expand of shrink 5%.气压、海拔高度：大气压力随着高度而变化，高度每增加610m，大气压力就降低1Psi(6900N/)。为了避免气压变化导致的中空玻璃变形，一般建议当制造地点与使用地点之间海拔高度差超过610m时，需要在中空玻璃上加毛细管。Air pressure/altitude: the atmospheric pressure changes when the altitude changes. Altitude gets 610 meters higher, the air pressure gets1Psi(6900N/) lower. To prevent the deformation under this circumstance, we suggest that when the altitude distance between the places produce and use is over 610 meters, add capillary tube to the glass.成像环境：规则的几何图形在玻璃上的成像看出的变形最为明显；轮廓线不明显的图像成像变形不明显；没有背景图案就看不出玻璃成像变形。Deformation of the regular geometric figure on the glass shall be the most obvious, while those images with vague contour line show unapparent deformation. Without background, we will not see any image deformation.四、安装因素 Installation安装受力：玻璃安装过程中如果有力作用在玻璃上，玻璃版面会发生变形从而影响成像。Stress: The stress happens during the installation have influence on the image formation.安装平整度：玻璃安装时的水平度和垂直度会影响单片玻璃的成像效果；幕墙隔片玻璃的平整度和一致性都影响幕墙整体的成像效果。Flatness: the levelness and rectangularity during installa