Screening is one of the most important parts in aggregate production. 它发生在破碎阶段(或多个阶段)之前和/或之后，并生产最终菠菜网最稳定正规平台_最全菠菜网大全所需的规格.
筛分的目的是将集料颗粒分离成均匀的大小. This is accomplished by using Vibrating Screens.
What is a Vibrating Screen?
振动筛是通过施加在机器上的激振力来按粒度分离集料的机器. The vibration lifts the material, causing it to stratify, 允许较小的材料从材料深度的顶部移动到材料的底部, thus exposing them to the screening surface.
Types of aggregate Vibrating Screens
干式筛分主要有两种类型的骨料振动筛:
- Horizontal Screens
- Inclined Screens
水平筛和倾斜筛的主要区别是倾斜筛利用重力来帮助物料的流动和输送.
However, both screens offer advantages for various applications.
Inclined Screens
Inclined Screens are the most popular for aggregate applications. 它们安装在倾斜的地方(根据筛网的类型和所需的切割，从5-45度不等)，并利用重力将材料推进筛网. 由于重力有助于物料的移动，这种筛需要低能量和低冲程.
Horizontal Screens
Horizontal Screens 是否可以在0度处平跑，但可以在任何方向上倾斜或下降10度. Because they don’t rely on gravity to move the material forward, Horizontal Screens require higher energy and a larger stroke.
这些类型的屏幕非常适合高度要求有限的低调应用, which makes them a great choice for portable plants. 在固定装置中，它们通常用作第三层或精加工筛. 更精细的筛分应用可以大大受益于这种类型的筛.
众所周知，他们的效率和可靠性，水平筛提供更准确的粒度. The high G-forces required to move the material ensure screen plugging is virtually eliminated, allowing for more continuous open area. 水平筛网的平面方向使物料在筛网上停留的时间更长，效率更高. It also makes them a great choice for wet screening applications.
How to select the right aggregate screen
因为筛选在生产最终菠菜网最稳定正规平台_最全菠菜网大全所需规格方面起着如此重要的作用, it is imperative that the right screen is selected for the job.
Vibrating Screen selection is based on the following factors:
- The maximum tons per hour
- A gradation of the feed material
- The type and weight of material
- The desired size of separation
- Any surface moisture on the material
- Any special operation requirements, including physical characteristics of the feed or product requirements
Sizing Vibratory Screens
Vibratory Screens come in a variety of sizes. They can range from 4’ to 12’ wide and 6’ to 32’ long. 筛网的宽度决定了筛网甲板的承载能力, while the length of the screen determines the overall efficiency of the screen. Typically, the length of the screen is 2.5 to 3 times the size of the width.
Every manufacturer has its own screen sizing formula. Screens are tailored to an operation based on the following factors:
- 基本容量-有多少材料将通过一个特定的开口
- Incline – how much of an incline, if any
- Deck – not all of the length of the lower decks may be utilized, 由于材料在到达下层甲板之前已经沿着上层甲板走了一段距离
- Oversize – how much material should go over the deck
- 半尺寸-有多少材料是介质开口的一半尺寸与高百分比的半尺寸, 物料通过筛孔的概率会更高, and the screen will be that much more efficient.
- Slot – how large the openings in the screen are
- 条件-适用于原料和工厂周围的大气. Is the material wet and sticky? Does it have a high percentage of clay? What is the temperature outside? Is it a wet or dry climate?
- 形状-圆形或立方体的粒子比扁平的粒子有更高的机会通过筛网开口, 细长的粒子必须找到合适的位置才能掉下去
- Weight – the density of the material
- Open area – the more open area on the screen, 粒子找到通过的机会就越大
How many decks do I need for my Vibratory Screen?
Vibratory Screens can be configured with one, two, three or four decks. 一些精细的筛选操作甚至可以有多达8个筛选层. Three decks are pretty common in the aggregate industry, 但屏幕甲板的数量取决于网站需要制作的菠菜网最稳定正规平台_最全菠菜网大全数量.
In a typical application where multiple products are being made, the top deck(s) of the screen makes the coarse cut, 中间甲板做中间切割，底部甲板做细切割.
每个筛板上都覆盖着筛介质，其中包含颗粒通过的开口. Screen media comes in many different forms, and the type of screen media plays an important role in screening efficiency.
What type of screen media is best for my Vibratory Screen?
屏幕媒体都是关于开放区域，或者屏幕上的开口数量. The more openings in the screen, 粒子通过的机会越多，过滤的效率就越高.
然而，屏幕上的开口越多，介质的磨损寿命就越短. 正确的屏幕介质的应用将平衡磨损寿命和效率.
Common types of screen media for aggregate applications include:
- Woven wire
- Polyurethane
- Rubber
- Hybrid
编织钢丝布是最一致、最通用的表演媒介菠菜网最稳定正规平台_最全菠菜网大全. 在大多数配置中，它的平均开放表面积为50-70%，对于由于菠菜网最稳定正规平台_最全菠菜网大全规格不同而需要频繁更换介质的操作，它提供了最大的灵活性. Overall screening efficiency is good with this type of media.
Wire media
聚氨酯更适合湿/洗筛网和高磨蚀材料的干燥应用. It provides 30-40% less open area than wire cloth; however, polyurethane offers extended wear life over wire media.
Polyurethane media
橡胶介质用于较重、较粗糙的材料，这些材料会损坏标准丝网. It is most often used for dry applications or abrasive materials. Rubber media has less openings than wire cloth, and therefore less throughput; however, they last much longer than wire screens.
Rubber media
混合介质将丝网与增强橡胶或聚氨酯条相结合，以适应筛网支撑. 它在高水分物料和高细粒比例的干筛应用中非常受欢迎. This type of media works to eliminate blinding and pegging, which ends the need to stop production to clean the screen. 它比聚氨酯提供更大的开放面积，比编织线更持久. 根据不同的应用，使用混合屏幕媒体可以提高40%的产量.
When sizing and selecting a Vibrating Screen for an aggregate operation, 请务必向制造商提供尽可能准确的有关进料和应用的详细信息. From there, 他们可以推荐哪种类型的屏幕(倾斜或水平)最适合网站, 以及所需的甲板数量和屏幕介质的类型，将提供最佳的磨损寿命和效率.
