Friday, October 11, 2019

MIXING AND BLOW ROOM, A SPINNING PROCESS

MIXING AND BLOW ROOM:

The blow room is the first operational assembly of different machines in the spinning of yarn which open, beat, clean the cotton and produce lap or even feed of material for the next process.

Objectives of mixing:

following are the main objectives of mixing:

To reduce the yarn cost by adding some cheaper cotton. 
To find desired yarn properties by adding various cotton varieties in mixing.

Objectives of blow room: 

the main objectives of blow room are given below;

To open the cotton tufts.

To clean the fibres.

To remove the dirt and dust from cotton fibres.

To prepare the lap ( cotton sheet ) of the fibres.

To Mix and blend various varieties of cotton.

To recycle the waste material.

Opening of the cotton tufts:

The cotton fibre reaches in the mill in the form of compressed bales. Due to the compact and compressed packing of cotton bales, the cotton changes into very big tufts and lumps. Thus this cotton necessitates to well open the fibres. This action is carried out with the help of openers in the blow room line. A very high degree of openness is achieved in the opening process. The tufts and lumps are broken by using various openers and beaters having blades. The smallest possible tuft size is achieved in this process. A very high degree of care is always taken to minimize fibre loss during the opening process. The degree of tuft opening also helps to maximize the cleaning of dirt, dust, broken seeds and trace etc.

Cleaning of the fibres:

Since cotton reaches spinning mills contains many impurities in it, so that it requires to clean perfectly during spinning. This is a well-known fact that impurities may be eliminated from the surface of the material only. The surface area of the material is increased up to the optimum level by the opening process. Blow room assembly does not remove full impurities. It eliminates 40% - 70% impurities from cotton. Cotton contains almost 18% trash. During the cleaning, the fibres are also eliminated with trash and foreign materials. The amount of removed waste is observed a and this waste is analysed to find the waste composition. The cleaning efficiency of the process is determined with the help of recorded data. It should always keep in mind that we have to increase the cleaning efficiency up to the optimum level, not up to the maximum level.

Removing the dirt and dust from the cotton fibres:

Foreign impurities( leaf, stone, iron particles, polyethene sheet, fibres of PP packaging, feather of birds and coloured fibres are removed from the cotton during opening and beating operations. It is a very important task of a blow room assembly. The dust removal in the blow room is done by an air suction device. This air suctioning is used either between the machines such as dust cages, dust extractors or within the machine by normal air separation.

Mixing and blending of different varieties of cotton:

The main objectives of mixing are the economy of production, the achievement of desired yarn quality and the improvement of yarn performance. In the mixing process, Two or more different varieties of cotton are mixed together.  Sometimes two or more types of fibres such as cotton and polyester are mixed together in this process. The material is mixed and blended well to find the homogeneous mixture of material. The possibility of random effect is terminated almost. Even the effect of material throughout the whole yarn surface is achieved.

Preparation of lap( even feed of material):

In the conventional below room assembly, a sheet of cotton fibre is prepared for even feeding of further process. This lap has even thickness and fixed width. The long continuous length of the cotton sheet (lap) is wound on a roll. This is feed to carding machine. Now these days, automatic tuft feeding installations are widely used.

Standards requirements of blow room line assembly:

A  modern blow room line assembly requires standards given below:
maximum working efficiency.
the cost-effective operation.
Ability to fit in maximum dimensions.
maximum safety. 
Easy operation. 
minimum maintenance.
• minimum maintenance cost
Good setting stability.
Reproducible machine setting.

                           


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