Иш кетма-кетлиги

 
 

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Job report 
Answer the following questions in the report: 
1. Determine the amount of moisture indicator according to regulatory 
documents. 
2. Give the conditions under which the experiment will be conducted. 
3. Compare the results and make a conclusion. 
 
Control questions: 
1. What technical means are used when smoothness is determined? 
2. Give the unit of measurement of smoothness. 
3. Introduce machine smooth paper technology. 
4. What is the function of the super calender? 
5. Under what conditions is the moisture content of paper studied? 
6. What is the sequence of work? 
7. Which formula is used to calculate humidity. 
8. How can moisture be connected? 
 
 
 
3-LABORATORY WORK 
DETERMINING THE ASHNESS OF THE PAPER
 
 
 The purpose of the work: mastering the methods of determining the grayness 
index from the main indicators of paper in practice. 
Tools and equipment: 
A muffle furnace is a heating device consisting of a refractory chamber. The 
object is placed in a muffle and modified by high temperature. 
 
 
A muffle furnace 
 
Determination of paper ash 
Ashiness of paper is determined by the amount of mineral fillers in 1 gram of 

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absolute dry paper. Ashiness is determined by heating and burning the paper. When 
heated, the moisture contained in the paper evaporates first, and then the substances 
contained in the fiber components, adhesives, fillers, etc., burn. Ash is formed due to 
inorganic (mineral) fillers. The amount of ash gives information about the amount of 
mineral fillers. Thus, the ratio of the mass of ash to the mass of absolute dry paper is 
called ash content and is an indicator of fillers. 
Students will store the paper sample given in this laboratory work in a desiccator 
with a bag after determining the moisture content. After drying the crucible, its 
constant weight is determined. The dried paper sample is placed in a crucible, weighed, 
then the paper is crushed, then the crucible is cooled in a desiccator and weighed. 
Procedure for writing a report. 
Grayness is determined by the following formula: 
K = (V – A) / (S-A)x x100% 
K - paper ash content: % 
A is the constant mass of the used crucible, g. 
V - constant mass of ash with a crucible, g. 
S is the mass of the paper with the crucible (taking into account moisture) 
The results obtained and other types of papers are also included in the table. 
The muffle is made of heat-resistant materials that do not allow combustion 
products to pass into the substance placed in them. Processing in the muffle can be 
done not only in air. There are muffle furnaces that heat the paper in a vacuum. Gases 
such as hydrogen, argon, helium or nitrogen can also be used instead of air. 
The airtightness of the camera creates the same thermal effect on the subject. 
The muffle takes a long time to heat up and it also requires a lot of energy. 
It is advisable to cover the muffle furnace with a special refractory paint. A 
special thermal insulation layer improves the properties of the oven. This serves to 
reduce heat loss and thereby increase the heat in the chamber. For the thermal 
insulation layer, you can use basalt wool, as well as perlite. 
Laboratory muffle furnaces are used in paper and cellulose laboratories. The 
main distinctive features of this type of furnaces are high technical equipment, the 
possibility of quick replacement of the muffle and almost ideal accuracy of setting 
working parameters. Laboratory equipment is mainly designed for conducting 
experiments in order to determine ways to improve the quality of a particular product. 
Therefore, the maximum accuracy of all indicators is mandatory. Laboratory muffle 
furnaces quickly heat up to the required temperature, are equipped with a timer and 
provide uniform heating of the air space inside the muffle. The muffle chambers in 
them have to be changed often, because it is necessary to work with different raw 
materials, which requires the use of muffles made from it. 
3. Determination of sheet curvature. 
Sheet dimensions: length and width - the deviation from the shape of a right angle and 
the ratio to the main indicators are determined in percentage. 
Job report 
Answer the following questions in the report 

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1. Give the conditions for determining constant weight. 
2. Compare the moisture content of the offset paper and the paper you have tested 
according to the regulations. 
3. Summarize.