5.1 概述在线视频

同学们好
Hello, class

我是华南理工大学
I am Li Bo from School of Light Industry and Engineering

轻工科学与工程学院的李擘
of South China University of Technology

今天我们学习《筛选净化机械与设备》
Today, let’s learn the contents of the Chapter of

这一章的内容
Screening and Cleaning Machinery and Equipment

筛选与净化与我们上一章
Screening and cleaning, as well as

介绍的洗涤和浓缩一样
washing and thickening I introduced in the last Chapter

都是制浆造纸过程中
are common processing units

较为常见的处理单元
in the process of pulping and papermaking

其主要作用是
whose main function is to

分离浆料中的杂质，净化浆料
separate impurities from the pulp and purify the pulp

使之达到产品质量
so as to make it meet the requirements

和正常生产的要求
of product quality and normal production

所用到的筛选设备
The screening equipment used

通常称之为筛浆机或者筛选机
is usually called a screen or strainer

而净化设备一般
while the Cleaning equipment

称之为除渣器或者净化器
is called generally a cleaner or purifier

由于纸浆中的杂质种类很多
Since there are various impurities in pulp

特别是废纸浆
especially waste pulp

经过加工、消费
after the multiple links including processing

回收和利用等多个环节
consumption, recollection and utilization

引入了各种各样的杂质
various contaminants, such as

如金属、砂石、塑料
metal, sandstone, plastic

玻璃、橡胶、油墨
glass, rubber, ink

胶黏物以及石蜡等
stickies and paraffin, are introduced

相对于原生浆中常见的
Compared with the common contaminants

分散不充分的纤维束
such as fiber bundles which are common

这样的杂质
and are not fully dispersed in the primary pulp

废纸浆的杂质形式显得更为多样
the contaminants forms in the waste pulp are more varied

特性也更为复杂
and the characteristics are more complex

对于纸产品质量以及设备
which will have seriously impact

都会造成严重的影响
on the paper quality and equipment

因此，需要充分利用
Therefore, it is necessary to make full use

设备的特点
of the characteristics of the equipment

同时结合杂质的特性
and remove the impurities effectively in combination

对其进行有效去除
with the characteristics of them at the same time

下面我们分别就这两类设备的
Here, I will introduce the working principle

工作原理、功能、评价方法
function, evaluation method and the common application

以及实际生产中常见的应用形式作以介绍
form in actual production of these two types of equipment

首先介绍筛选设备
First, let’s introduce the screening equipment

筛选设备是利用
The screening equipment works

阻留粗大杂质的原理工作的
on the principle of intercepting large impurities

起阻留分离作用的是筛板
The screen plate plays a role of retention and separation

筛板上的开口可以是孔
and the opening on the screen plate

也可以是缝
can be holes or slots

当杂质的尺寸、形状大于
When the size and shape of the contaminants are larger

筛孔或者筛缝时
than the screen hole or the screen slot

就会被拦截去除
it will be intercepted and removed

如果是废纸浆
If it is waste pulp

那么还要考虑杂质的形变性因素
deformation factor of the impurity shall be considered

这主要是针对胶黏物而言
This is mainly for the stickies

如果是弹性形变性良好
If they have good elastic shape deformation

尽管其颗粒尺寸大于筛缝
although its particle size is larger than the screen slot

仍然有可能因为形变
it is possible to pass through the screen slot

而通过筛缝
because of the deformation

而不能将其从浆料中分离出来
and it cannot be separated from the pulp

反之，如果弹性形变性
on the contrary, for the stickies

不太好的胶黏物
with poor elastic shape deformation

当其颗粒尺寸较大时
when their particle size are larger

那么被筛选分离出来的几率就相对较大
then the probability of separation is relatively large

因此，筛选设备实质上是利用
Therefore, the screening equipment essentially uses

杂质的尺寸、形状和形变性特性
the size, shape and shape deformation characteristics

三方面因素对其进行去除的
of the impurities to remove them

此外，筛浆机不仅仅
In addition, the strainer not only

具有去除杂质的功能
has the function of removing impurities

它还具有纤维分级的作用
but also has the function of fiber classification

通常称之为纤维分级机
which is commonly called fiber classifier

同样也是利用阻留原理
It also uses the principle of retention

主要用于长纤和短纤的分离
which is mainly used for the separation of long fiber and short fiber

在旧瓦楞箱板纸造纸应用中较为广泛
and is widely used in the papermaking using old corrugated box

是合理利用该类纤维
It is an effective measure to make reasonable use

提高其经济性的有效措施
of this kind of fiber and improve its economy

接下来我们介绍一下净化设备
Next, let's introduce the purifying equipment

与筛选设备不同的是
Unlike the screening equipment

净化设备没有筛板
the purifying equipment does not have a screen plate

它的工作原理是利用
and its working principle is to use

杂质与纤维之间的密度差
the density difference between impurities and fibers

通过离心作用将其去除的
to remove them by centrifugation

这里的密度差指的是
The density difference here is that

杂质的密度
the density of the impurities

大于或小于纤维
is greater than or less than that of the fibers

具有密度差的杂质
Most impurities with the density difference

多数可以通过净化器从浆料中去除
can be removed from the pulp through the cleaner

但是密度与纤维接近的杂质
but the impurities with the density close to the fiber

很难通过这种方法去除
are difficult to be removed by this method

常见的净化设备有
Common purifying equipment includes

离心除渣器和涡旋除渣器等
centrifugal cleaner and vortex cleaner, etc.

好，下面我们介绍
OK, let’s introduce the evaluation indicators

筛选和净化的评价指标
f or screening and purifying

第一个是筛选或者净化效率
The first is screening or purifying efficiency

指的是进浆和良浆的
It refers to the percentage of the difference

尘埃度之差占
between the dirt count of the feeding pulp

进浆尘埃度的百分比
and the accepted stock in the dirt count of the pulp

第二个是排渣率
The second is reject rate

指的是排除的浆渣
It refers to the percentage of discharged reject

占进浆量的百分比
in the feeding pulp volume

习惯上，排渣率较大时
Traditionally, when the reject rate is larger

如达到10%以上时
if it reaches more than 10%

排除的浆渣称为尾桨
the discharged reject is called tailings

排渣率较小（如低于5%）
when the discharged reject rate is smaller (if less than 5%)

或浆渣中好纤维量较少时
or the amount of good fiber in the pulp reject is smaller

排出的浆渣称之为粗渣
the discharged reject is called coarse reject

对于除渣器
For cleaner

还有一个性能评价指标
there is also a performance evaluation indicator

称为净化指数
called purifying index

是指浆料的向心加速度
It refers to the centripetal acceleration of the pulp

乘以其在内部的停留时间
multiplied by the ratio of its internal residence time

与除渣器圆柱部分的直径之比
to the diameter of the cylinder part of the cleaner

是对除渣器的净化性能
and it is an indicator to evaluate

进行评价的一个指标
the purifying performance of the cleaner

最后我们介绍筛选和净化设备
Finally, I will introduce the common application forms

常见的应用形式
of screening and purifying equipment

由于这两种设备的
Because the single machine processing capacity

单机处理能力都相对有限
of these two types of equipment is relatively limited

在实际生产中为了保证生产量
in order to ensure the production capacity in actual production

通常都是成组的使用
they are usually used in groups

分组的形式有两种
There are two forms of grouping

一种是分级，一种是分段
one is stage, and one is section

这里先解释一下 “级”和“段”的概念
Let’s first explain the concepts of "stage" and "section"

“级”是以提高良浆质量为目的
The "stage" refers to the application form of continuous treatment

对出浆继续处理的应用形式
for pulping with the purpose of improving the quality of accepted stock

原浆和良浆经过
How many times that raw pulp and accepted stock

筛选或净化设备几次
are subject to the screening or cleaning equipment

就称为几级
it is called the stage with that times

而“段”是以回收浆渣中的纤维为目的
while "section" is the application form of treating the reject

对渣浆进行处理的应用形式
with the purpose of the recollection of the reject

同样的，原浆和渣浆
Similarly, how many times the raw pulp and reject

经过筛选或者净化设备几次
are subject to the screening or cleaning equipment

就称为几段
it is called section with that time

由于段与段之间的
As there are different forms of

良浆和渣浆走向有不同的形式
accepted stock and reject direction between sections

大致可以分为三种情况
it can be roughly classified into three types of cases

第一种
For the first type

在一级三段的排列中
in the arrangement of the first stage three-section

后一段的良浆依次
the accepted stock of the latter stage

进入前一段的进浆
enters the previous stage in turn

而渣浆依次送到后一段
and the reject is sent to the latter stage in turn

这样的排列形式称之为“全阶梯式”
which is called the "full stepped type"

第二种
For the second type

同样还是一级三段排列
it also is the arrangement of the first stage three-section

各段良浆和渣浆走向
the direction of the accepted stock of each section and the reject

基本与“全阶梯式”类似
is basically similar to the "full stepped type"

只是第二段良浆
except that the second section of accepted stock

没有进入上一段进浆
does not enter the previous section to feed

而是直接进入良浆管路
but directly enter into the accepted stock pipeline

这样的排列形式称之为“半阶梯式”
and such arrangement form is called "half stepped type"

第三种
For the third type

一级三段的排列中
in the arrangement of the first stage three-section

各段的良浆
the form of the accepted stock of each section

均进入良浆系统
entering into the accepted stock system

渣浆依次进入下一段的这个形式
and the reject entering into the next stage in turn

称之为“全向前式”
is called "all-forward type"

对比三种排列形式
From the comparison of the three arrangements

可以看出
it can see that

“全阶梯式”筛分效率最高
"full stepped type" screening efficiency is the highest

但是处理成本最高
while the processing cost is the highest

“半阶梯式”筛分效率较低
the "half stepped type" screening efficiency is low

比较经济
and relatively economic

但是良浆的等级也低
while the grade of accepted stock is also low

最后，“全向前式”排列方式
finally, for the "all-forward type" arrangement

处理成本虽然最低N although the processing cost is the lowest

但是良浆质量也最差
\ the quality of accepted stock is also the worst

通常是很少会这样使用的
it is usually rarely used in this way

以上就是有关
The above is a brief introduction of

筛选和净化设备的概要介绍
screening and cleaning equipment

接下来的两节
In the next two sections

我们将分别介绍
let’s introduce screening equipment

筛选设备和净化设备
and purifying equipment respectively

好，这节课的内容我们就讲到这里
OK, that’s all for today

谢谢大家
Thank you