Blow Room: Blow Room consists of a number of machines used in succession to open and clean the cotton fibre to the required degree. Almost 40 to 70% trash is removed in this section.
Blow Room Section: A section in which the supplied compressed bales are opened, cleaned and blending or mixing to form uniforms lap of specific length is called Blow Room section. The cleaning efficiency of blow room is 60 to 65%. This is the first section of spinning line for spinning cotton yarn.
Operation in Blow Room:
i. Opening: To open the compressed bales of fibres & to make the cotton tuft a small size as for as possible.
ii. Cleaning: To remove the dirt, dust, broken seeds broken leaves, stalks and other foreign materials from the fibres.
iii. Bending or Mixing: To make good value of yarn and to decrease the production cost by mixing different grade of fibres.
iv. Lap forming: To transfer the opened and cleaned fibres into a sheet form of definite width and uniform unit length which is called lap, to roll the lap of predetermined length in a cylindrical shape around a lap pin and to transfer the lap from the lap pin to a rod to suitable handle and feed it to subsequence processing carding m/c.
Action in blow room: The actions of the machines in any blow room range fall into one or more of four main groups namely:
1. Action of opposite spike: (opening): The action of opposite spikes is opening the cotton fibre. By this action, the large pieces of cottons have been reduced in size.
2. Action of Air current: (Transport + Cleaning): During processing, the movement of cotton from machines to machine is done by air current. It also helps the separation of lint and trash.
3. Action of Beaters: (Cleaning & Opening): Beaters are responsible for removing almost all of the impurity extracted in the blow room. Beater also helps in opening of cotton fibre.
4. Action of regulating motion: (Uniform output): The action of regulating motion gives the uniform output of cotton fibre by the help of swing door and swing paddle
- Electrical photocell
- Air pressure system
Basic operations in Blow Room:
1. Opening: Opening is the 1st operation required, carried out to the stage of flocks in the blow Room and to the stage of individual fibres in the Card. Flock weight can be reduced to about 0.1 mg in the Blow Room.
2. Cleaning: A blow Room Installation removes approx. 40-70% of the impurities. The result is dependent on raw materials, on the machines and on the environment conditions. From the graph, cleaning effect cannot and should not be the same for all impurity level, since a lot of dirt can be removed more easily than a little. In order to clean, it is necessary to eliminate about as much fibre as foreign materials. Percentage of total material eliminated, in cleaning efficiency%,
CE =(AT-AE)/AT
= (Total waste - Good fibre eliminated)/Total waste
3) Blending: Fibres can be blended at various stages of the process. These possibilities should always be exploited. Example- transverse doubling. The start of the process is one of the most important stages for blending. Intensive blending in a suitable blending m/c must be carried out after separate flock extraction from individual bales of layout. This blending operation must collect the sequentially arriving bunches of fibres from individual bales and mixes them thoroughly.
4) Dust Removal: Almost all manufacturers of blow room machinery now offer dust removing machines or equipment in addition to opening and cleaning. Dust removal is not an easy operation, since dust particles are completely enclosed in the flock and hence held back during suction.