Blow Room line by Rieter

INTRODUCTION

When the bales of cotton arrive at a spinning mill, these are subjected to the very first process, which is definitely Blow Room.

Basic operations in the blow room: 

Ø  Opening 

Ø  Cleaning 

Ø  Mixing or blending 

Ø  Dust removal 

Ø  Uniform feed to the carding machine 

INPUT OF BLOWROOM

The material input to the blow room was in the compressed form and full of trashes or impurities i.e. leaves, seed, chaff, metallic particle and dusts etc.

OUTPUT OF BLOWROOM

After going through the processes of the blow room, the output in the form of small tufts and it is cleaned and opened.

PRINCIPLE OF ACTION OF MACHINES IN BLOW ROOM:

·         Action of opposite spike:

o   This action reduces the large tufts of cotton into small ones.

·         Action of air current

o   The movement of cotton fibers from machine to machine is done by the effect of continuous air current,

o   This air current also helps in separation of trashes

·         Action of beaters:

o   Beaters are resposible for removal of all types of impurities

o   Helps in opening of cotton

·         Action of regulation motion

o   Gives uniform output of cotton fiber by help of  swing doors and swing paddels.

A blow room installed by rieter company is shown in the figure

A blow room installed by Rieter company is shown in the figure

DETAILS OF PROCESSES IN BLOW ROOM:

Blow room installations consists of a sequence of different machines to carry out the above mentioned operations. Moreover Since the tuft size of cotton becomes smaller and smaller, the required intensities of processing necessitates different machine configuration.

Opening:

Opening in blow room means opening into small flocks. Technological operation of opening means the volume of the flock is increased while the number of fibres remains constant. i.e. the specific density of the material is reduced.

·         Many types of opener and beaters are used to open and clean the tufts some of them are given here

MACHINE USED: (BALE BREAKER)

The opening  process is being done now a days in the spinning lab of University College of Textile Engineering BZU using Reiter unifloc machine shown in the figure below

CLEANING:

The process to remove dirt, dust, broken seeds, broken leafs and other trashes is called cleaning.

OBJECTIVES OF OPENING AND CLEANING:

·         To reduce the density of raw cotton mass

·         To reduce the tuft size exposing new fiber surfaces, that allows impurities to be removed

·         To reduce the tuft size in order to improve the mixing of cotton and regularity of the feedstock delivered to the next process.

·         To achieve these objectives with a minimum damage to the fibers

FACTORS INFLUENCING CLEANING:

·         The larger the dirt particle , the better they can be removed. Since almost every blowcroom machine can shatter particles, as far as possible a lot of impurities should be eliminated at the start of the process.

·         The higher the degree of opening, the higher the degree of cleaning. A very high cleaning effect is almost always purchased at the cost of a high fibre loss. Higher roller speeds give a better cleaning effect but also more stress on the fibre. If cotton is opened well in the opening process, cleaning becomes easier because opened cotton  has more surface area, therefore cleaning is more efficient. 

·         The cleaning efficiency is strongly dependent on the TRASH %. It is also affected by the size of the particle and stickiness of cotton. Therefore cleaning efficiency can be different for different cottons with the same trash %. There is a new concept called CLEANING RESISTANCE. Different cottons have different cleaning resistance.

Cleaning efficiency may b calculated using formula

·         Due to machine harvesting , cotton contains more and more impurities, which furthermore are shattered by hard ginning. Therefore cleaning is always an important basic operation. 

·         In cleaning, it is necessary to release the adhesion of the impurities to the fibres and to give the particles an opportunity to separate from the stock. The former is achieved mostly by picking of flocks, the latter is achieved by leading the flocks over a grid.

·         In a beating operation, the flocks are subjected to a sudden strong blow. The inertia of the impuritiesaccelerated to a high speed, is substantially greater than that of the opened flocks due to the low air resistance of the impurities. The latter are hurled against the grid and because of their small size, pass between the grid bars into the waste box, while the flocks continue around the periphery of the rotating beater. 

·         Air streams are often used in the latest machine sequence, to separate fibres from trash particles by buoyancy differences rather than beating the material against a series of grid bars.

MACHINE USED FOR CLEANING:

Many different types of cleaning machines with different type of beaters are being used in textile industry, But in blow room installed in Spinning lab of UCTE BZU uniclean of Rieter is being used the short description about uniclean is given below

CONSTRUCTION PARTS:

1.      Cleaning cylinder

2.      Cleaning Grid

3.      Air lock cylinder

4.      Material feed

5.      Material outlet

6.      Exhaust air to filter

7.      Waste removal

But instead of the material rotating three times inside the machine, it is forced to pass over the grid five times, always presenting new surface areas to it. The tufts not only pass over the grid five times, they also pass over a specially arranged perforated sheet five times. The chamber behind this sheet is a low-pressure chamber. The air suction through this sheet provides very efficient dedusting. The waste is collected inside the machine and fed to the waste transport via an airlock cylinder. Intermittent suction and connection to continuous suction is possible.

MIXING COTTON

To have produced high quality and uniform yarn, we interweave material very well. This concerns not only the production of cotton blends with other textile materials, but also 100% cotton, because cotton quality and characteristics in different packages may vary. Our task is to create high-quality homogeneous mixture. Such a mixture will ensure that the properties at any point will be the same yarn. Perfect mixing to remove the differences in length, fineness, strength,color and fiber contamination.

MULTI MIX:

The machine is made up of three parts:

·         a storage section,

·         an intermediate chamber

·         a delivery section.

Flocks are feed simultaneously into 6 J-shaped chambers (2) arranged one behind other in storage section. A conveyor belt (3)  leads the stock through the intermediate chamber to the take-off unit. The material columns are diverted out of vertical to horizontal. In addition to a condensing effect, this 90º bend in the material flow also produces a shift in timing and special distribution of transport of flocks from first chamber to last chamber. This in turn results in good long term blending. Therefore as in blending opener, material is extracted from the middle chamber and subjected to further opening step between an inclined spiked lattice (5) and an evener roller (7), giving an additional good short term blending. An optical sensor (6) controls the quantity of material in the mixing chamber. Behind the spiked lattice there is a take-off roller and a simple pneumatic suction feed to the next machine.

DUST REMOVAL:

An often underestimated task of the blow room line is the removal of dust. However, it is as important as the removal of impurities. Dedusting in the blow room happens by air suctioning only, either between the machines, e.g. by dust cages, dust extractors , etc., or within the machine by normal air separation. Every blow room machine must be capable of extracting dust, so that special dedusting machines should be needed. The efficiency depends not only on the devices but also on the size of the flocks. The smaller the flocks, the higher is the efficiency.

USING UNIFLEX:

Uniflex is used for further opening, cleaning, and dedusting of cotton of staple fibers.

A fan in the feeding duct helps  to supply the machine with raw material. A specialy designed flip flop feeding device (1) forms a homogeneous wadding in the lamina chute (2) over the whole length and width. The dust laden transport air is extraced through the lamina chute. The adjustable depth of the chute allows for homogeneous filling operation to take place according to the production requirment. Two drums (3) positioned at the bottom of the chute extract the material. One of them (4) is perforated and allow additional dedusting. Feeding roller (5) and the servo motor controlled adjustable feeding plate passes the fiber onto the opening and cleaning unit where final cleaning takes place. After the operation of this machine the material is then feed to carding machine.

TRANSPORTATION OF MATERIAL FROM BLOW ROOM TO CARD

For the transportation of the fibers from the blow room to the card the chute feed system is used Spinning Mills. In chute feed system the ducting pipes and the chute is used. The fibers are taken from the last roller through the condenser, which creates the suction and then feed them to the card machine.

The condenser is very important part of the blow room. Its main function is to take the fibers from the back part and supply them to the next part. All this operation is down on the bases of the sucking function of the condenser.

Basically the condenser consists on a fan, stripping roller and a perforated roller. The fan is connected with a high-speed motor, which rotates it at a high speed. The grid roller has holes on its surface, which helps it to suck the fibers from the back machine.

When the fan and the grid roller rotates with the help of the motor, an air vacuum is generated which sucks the fibers from the back rollers through the holes of the grid roller. The stripper roller removes the fibers from the perforated roller and through them into the chute.

General factors which affect the degree of opening , cleaning and fibre loss are, 

·         thickness of the feed web 

·         density of the feed web 

·         fibre coherence 

·         fibre alignment 

·         size of the flocks in the feed (flock size may be same but density is different) 

·         the type of opening device 

·         speed of the opening device 

·         degree of penetration 

·         type of feed (loose or clamped) 

·         distance between feed and opening device 

·         type of opening device 

·         type of clothing 

·         point density of clothing 

·         arrangement of pins, needles, teeth 

·         speeds of the opening devices 

·         throughput speed of material 

·         type of grid bars 

·         area of the grid surface 

·         grid settings                               

·         airflow through the grid 

·         condition of pre-opening 

·         quantity of material processed, 

·         position of the machine in the machine sequence 

·         feeding quantity variation to the beater