Blow room machines

• A blow room line consist of following machines

– Bale opener (opening)

– Coarse cleaner (removes course trash)

– Blending (homogeneous blending)

– Fine cleaner (removing fine trash)

Bale breaker

Material flow in bale breaker

Working of bale breaker • The creeper lattice transfers the fed material to the feed lattice.

• The feed lattice then shifts the material to the inclined lattice.

• Inclined lattice have rows of spikes which take the material from feed lattice and carry it upwards.

• The evener roller present at the top of inclined lattice rotates in the opposite direction to the lattice and bigger tufts of cotton are bounced back on inclined lattice. The distance between the evener roller and inclined lattice can be adjusted. More distance means less opening and more production and vice versa. Due to this kind of opening, mixing also takes place automatically.

• The stripping roller moves in the same direction as the inclined lattice. It removes the material entangled in the spikes of inclined lattice and guide it to the outlet.

• The cleaning roller removes the material from evener roller which fall back in the chamber for re-opening.

• Microdust is removed from the cotton by suction from the suction fan at the top of the machine.

• The swing door works to keep the chamber 75% filled. When the volume of the material increases beyond this limit, the swing door operates a limit switch to stop the creeper lattice and consequently the machine feeding is stopped. It is connected to the creeper lattice.

• Cleaning efficiency of bale breaker is 30—40%.

• Production of the bale breaker is about 1000—1200 lb/hr.

• Advantage: Bale breaker produces a very less loss of lint (short fibres) along with waste e-g, if a total of 40% impurities are dropped, then out of this amount, lint loss is only 20% and the remaining waste is 80%.

Step cleaner

Parts of step cleaner • Beaters • There are six beaters in the step cleaner designed to rotate in the same

direction. These beaters are arranged in a row at an angle of 45°. Each beater consists of a tabular body with 4 spikes of elliptical cross section welded on each. The speed of the first beater is 500—600 rpm and the speed of every other beater increases about 25—30 rpm from its previous beater.

• Grid Bars • A grid bar system is fitted under each beater for the waste removal. The

grid bars can be adjusted by altering the bar angle or bar spacing according to the trash contents of the material being processed. Less spacing and small angle of bars is required when the material has less waste and vice versa.

• Baffle Plate • A baffle plate is arranged b/w every two consecutive beaters. This plate

prevents recycling of material by breaking the circle of air currents. • Trash Box • A trash box is located below the grid bars. The heavy impurities from the

material are dropped into the trash box via grid bars.

Working of step cleaner • In step cleaner, material transfer occurs by the rotating action of consecutive

beaters. • The step cleaner is a very effective m/c for opening and cleaning of material. • The material is fed to the m/c at a regular rate with the help of feeding trunk. After

entering, it immediately comes under the action of six beaters each having 4 spikes.

• Entangled in the beater spikes, the material rotates with the rotating beater. After covering almost half a revolution, it is transferred to the next beater through its spikes

• A baffle plate located b/w two consecutive beaters stops the recycling of material by breaking the circle of air currents.

• The process goes on similarly till the material after passing upwards from one beater cylinder to the next and over each individual cleaning grid reaches the last beater.

• The heavy impurities are collected in the trash box after dropping from the grid bars.

• The outlet or delivery end is followed by the last beater. • The m/c has a good cleaning efficiency i-e, 30—45 %. • Disadvantage: It adds 30% more neps and consumes a very large amount of energy

as compared to waste extraction.