筛选 是总产出中最重要的部分之一吗. It takes place before and/or after the crushing stage (or stages) and produces the specifications required of the final products.
The purpose of screening is to separate a flow of aggregate particles into uniform sizes. 这是通过使用来完成的 振动屏幕.
振动屏幕 are machines used to separate aggregates by particle size by means of an exciting force applied to the machine. 振动使材料上升, 使其分层, allowing the smaller material to move from the top of the depth of material to the bottom of the material, 从而使它们暴露在筛选表面.
There are two main types of aggregate vibrating screens for dry screening applications:
The primary difference between 横屏 and 倾斜屏幕 is the Inclined Screen uses gravity to help with the flow and conveyance of the feed material.
倾斜屏幕 聚合应用程序最受欢迎吗. They are installed on an incline (anywhere from 5-45 degrees depending on the type of screen and the required cut) and employ the use of gravity to propel material down the screen. Since gravity helps to move the material, this type of screen requires low energy and low stroke.
横屏 are run flat at zero degrees but can be inclined or declined as much as 10 degrees in either direction. 因为它们不依赖重力来推动物质前进, 横屏需要更高的能量和更大的行程.
These types of screens are ideal for low-profile applications where height requirements are limited, 这使得它们成为便携式植物的绝佳选择. In stationary plants, they are often used as tertiary or finishing screens. Finer screening applications can greatly benefit from this type of screen.
Known for their efficiency and reliability, 横屏 offer more accurate particle sizing. 移动材料所需的高重力保证 屏幕堵塞 几乎被消除，允许更多连续的开放区域. The flat orientation of the Horizontal Screen allows material to be retained on the screen longer for higher efficiency. 这也使它们成为湿筛应用的一个很好的选择.
Because screening plays such an important role in producing the required specifications of a final product, 这是必要的 选择右屏 为了这份工作.
- 特殊操作要求, 包括饲料或信用赌场游戏网址的物理特性要求
振动筛有多种尺寸. 它们的宽度从4英尺到12英尺不等，长度从6英尺到32英尺不等. The width of the screen determines the carrying capacity of the screen deck, 而屏幕的长度决定了整体 筛网效率. 通常情况下，屏幕的长度为2.宽度的5到3倍大小.
- Basic capacity – how much material is going to pass through a certain opening
- 甲板-不是所有较低的甲板长度都可以被利用, as material has already traveled down some length of the upper decks before reaching the lower ones
- Oversize -甲板上应该覆盖多少材料
- Half size – how much material is half the size of the media opening With a high percentage of half size, the probability of the material passing through the screen openings will be higher, 这样屏幕就会更有效率.
- Condition – applies to both the feed material and the atmosphere around the plant. 材料是湿黏的吗? 它的粘土含量高吗? 外面的温度是多少? 气候是潮湿还是干燥?
- Shape – Round or cubical particles have a higher chance of passing through the screen openings than a flat, elongated particle that has to find just the right position to fall through
- 开放区域-屏幕上更开放的区域, the better the chance particles will find an opportunity to pass through
振动筛可配置为一层、二层、三层或四层. Some fine screening operations can even have as many as eight screening decks. 三层甲板在综合行业中很常见, but the number of screen decks depends on the number of products the site needs to make.
在一个生产多种信用赌场游戏网址的典型应用中, 屏幕的顶部甲板使粗切割, the middle deck(s) makes a middle cut and the bottom deck(s) make the fine cut.
Each screen deck is covered with screen media containing the openings for the particles to pass through. 屏幕媒体有许多不同的形式 屏幕媒体类型 对筛分效率起着重要作用.
Screen media is all about open area, or the number of openings in the screen. 屏幕上的开口越多, the more opportunities the particles will have to pass through and the more efficient the screen will be.
However, more openings in the screen can decrease the wear life of the media. The correct screen media for an application will balance both wear life and efficiency.
Wove wire cloth is the most consistent, versatile performing media product. It averages 50-70% open surface area in most configurations and provides the most flexibility for operations that need to make frequent media changeouts due to varying product specifications. 这种介质的整体筛选效率较好.
聚氨酯 is better suited for wet/wash screens and dry applications with highly abrasive materials. It provides 30-40% less open area than wire cloth; however, 聚氨酯提供延长磨损寿命的电线媒体.
橡胶媒体 is used for heavier, coarser materials that can damage standard wire screens. 它最常用于干燥应用或研磨材料. 橡胶介质的开口比铁丝布少, and therefore less throughput; however, 它们的使用寿命比有线屏幕长得多.
混合动力 media combines wire screen with reinforced rubber or urethane strips to fit screen supports. It is highly popular in dry screening applications with high moisture materials and a high proportion of fines. 这种类型的媒体可以消除盲目和固定, 这样就不再需要停止生产来清洁屏幕了. It provides more open area than polyurethane and lasts longer than woven wire. Depending on the application, production can increase 40% using hybrid screen media.
当选择振动筛进行集料操作时, be sure to provide the manufacturer with as much accurate detail about the feed material and the application as possible. 从那里, they can recommend what type of screen (Inclined or Horizontal) is best for the site, as well as the number of decks required and the 屏幕媒体类型 that will provide the best wear life and efficiency.